Membrane elements, filter elements and water purification devices

Abstract

The present invention discloses a membrane element, a filter element, and a water purification device, relating to the field of water treatment technology. The membrane element may include: a water collection pipe; a first membrane unit, a second membrane unit, and a third membrane unit wound around the water collection pipe; the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; when the first, second, and third membrane units are in an unfolded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the same side, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the same side; etc. This application can further increase the flow rate on the raw water side of the membrane element, thereby increasing the contamination resistance of the membrane element and thereby extending the service life of the membrane element.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a membrane element, a filter element and a water purification device. Background Art

[0002] At present, water purification devices usually use filter elements to treat tap water to obtain drinking water for people. The filter elements used in existing water purification devices can be of different forms and types. One type of filter element uses a rolled membrane element to filter and treat raw water. The front interlayer of the membrane unit in the membrane element forms the raw water flow channel, and the back interlayer forms the filtered water flow channel. Under the premise of the same membrane area, the longer the membrane page of the membrane unit, the longer the raw water flow channel, and the fewer the membrane pages of the membrane unit, the faster the membrane surface flow rate. However, when the length of the raw water flow channel of a single membrane element is too long, the length of the corresponding filtered water flow channel is also too long, resulting in a larger back pressure on the filtered water side of the membrane element, resulting in a decrease in the water production of the filtered water of the membrane unit under the same water production pressure. In the membrane element of the prior art, a membrane element is formed by winding two membrane units connected in series and stacked in sequence on a water collection pipe. Under the same membrane area, the length of the raw water flow channel of the membrane element can be increased, and its filtered water flow channel is divided into multiple channels. Therefore, the length of each filtered water flow channel connected to the water collection pipe can be greatly reduced, and the flow rate of raw water in the raw water flow channel will be increased. Through this design, the water production of the filtered water of the membrane unit can be improved to a certain extent, and the scouring intensity of the raw water on the pollutants attached to the surface of the membrane page is increased, thereby improving the pollution resistance of the membrane element and extending its service life.

[0003] Under normal use, the service life of the membrane element under the above structure is short and needs to be replaced after a period of time, which is not economical and environmentally friendly. Therefore, a new membrane element is urgently needed. While ensuring the filtered water production, it can further increase the overall anti-pollution ability of the membrane element, thereby better improving the service life of the membrane element. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a membrane element, a filter element and a water purification device, which can further increase the flow rate on the raw water side of the membrane element to increase the pollution resistance of the membrane element, thereby improving the service life of the membrane element.

[0005] The specific technical solution of the embodiment of the present invention is:

[0006] A membrane element, comprising:

[0007] water collection pipes;

[0008] A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit;

[0009] When the first membrane unit, the second membrane unit and the third membrane unit are in the expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; the membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the expanded state, and the second side has at least one of the connection points between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and the connection points between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit.

[0010] In a preferred embodiment, the raw water inlet and the waste water outlet of each membrane unit are not located on the same side.

[0011] In a preferred embodiment, the membrane element further has a third side and a fourth side facing each other in the unfolded state, and the third side and the fourth side are connected to the first side and the second side respectively;

[0012] The second side, third side and fourth side of the membrane element are formed with the connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit, the connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit, the raw water inlet of the first membrane unit and the wastewater outlet of the third membrane unit.

[0013] In a preferred embodiment, the first membrane unit, the second membrane unit and the third membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the second membrane unit and the third membrane unit are stacked in sequence and wound together on the water collecting pipe.

[0014] In a preferred embodiment, the membrane element further has a third side and a fourth side opposite to each other in the unfolded state, the third side and the fourth side being connected to the first side and the second side respectively, and when the membrane element is in the rolled state, the third membrane unit is located on the outside;

[0015] The raw water inlet of the first membrane unit and the waste water outlet of the third membrane unit are located on the third side when deployed;

[0016] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed;

[0017] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the fourth side when deployed;

[0018] The raw water inlet of the first membrane unit is arranged on the third side close to the first side;

[0019] The wastewater outlet of the second membrane unit is arranged on the fourth side close to the first side;

[0020] The raw water inlet of the third membrane unit is arranged on the fourth side close to the first side;

[0021] The wastewater outlet of the third membrane unit is arranged on the third side close to the second side.

[0022] In a preferred embodiment, the membrane element further has a third side and a fourth side facing each other when in the unfolded state, the third side and the fourth side being connected to the first side and the second side, respectively, and the first membrane unit is located on the outside when the membrane element is in the rolled state;

[0023] The raw water inlet of the first membrane unit and the waste water outlet of the third membrane unit are located on the third side when deployed;

[0024] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the fourth side when deployed;

[0025] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed;

[0026] The raw water inlet of the first membrane unit is arranged on the third side close to the second side;

[0027] The wastewater outlet of the first membrane unit is arranged at the fourth side close to the first side;

[0028] The raw water inlet of the second membrane unit is arranged on the fourth side close to the first side;

[0029] The wastewater outlet of the third membrane unit is arranged on the third side close to the first side.

[0030] In a preferred embodiment, the membrane element further comprises a water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit and / or the third membrane unit, and the membrane element is in an unfolded state, and the water-blocking layer is stacked together with the first membrane unit, the second membrane unit and part of the membrane units in the third membrane unit;

[0031] The second side also has one of a raw water inlet of the first membrane unit and a waste water outlet of the third membrane unit.

[0032] In a preferred embodiment, the first membrane unit, the second membrane unit, the water-blocking layer and the third membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the second membrane unit, the water-blocking layer and the third membrane unit are stacked in sequence and wound together on the water collecting pipe.

[0033] In a preferred embodiment, the membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, wherein the third side and the fourth side are connected to the first side and the second side respectively; when the membrane element is in the rolled state, the third membrane unit is located on the outside;

[0034] The first side of the waterproof layer is sealed with the side of the second side of the second membrane unit close to the third membrane unit and the side of the second side of the third membrane unit close to the second membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the third membrane unit close to the first membrane unit and the side of the second side of the first membrane unit close to the third membrane unit; the side of the second side of the first membrane unit close to the second membrane unit is sealed with the side of the second side of the second membrane unit close to the first membrane unit;

[0035] The raw water inlet of the first membrane unit is located on the third side when it is deployed;

[0036] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed;

[0037] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the fourth side when deployed;

[0038] The wastewater outlet of the third membrane unit is located at the second side when deployed;

[0039] The raw water inlet of the first membrane unit is arranged on the third side close to the first side;

[0040] The wastewater outlet of the second membrane unit is arranged on the fourth side close to the first side;

[0041] The raw water inlet of the third membrane unit is arranged on the fourth side close to the first side.

[0042] In a preferred embodiment, the first membrane unit, the water-blocking layer, the second membrane unit and the third membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the water-blocking layer, the second membrane unit and the third membrane unit are stacked in sequence and wound together on the water collecting pipe.

[0043] In a preferred embodiment, the membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, wherein the third side and the fourth side are connected to the first side and the second side respectively; when the membrane element is in the rolled state, the first membrane unit is located on the outside;

[0044] The first side of the waterproof layer is sealed with the side of the second side of the second membrane unit close to the first membrane unit and the side of the second side of the first membrane unit close to the second membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the first membrane unit close to the third membrane unit and the side of the second side of the third membrane unit close to the first membrane unit; the side of the second side of the third membrane unit close to the second membrane unit is sealed with the side of the second side of the second membrane unit close to the third membrane unit;

[0045] The raw water inlet of the first membrane unit is located at the second side when deployed;

[0046] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the fourth side when deployed;

[0047] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed;

[0048] The wastewater outlet of the third membrane unit is located on the third side when deployed;

[0049] The wastewater outlet of the first membrane unit is arranged at the fourth side close to the first side;

[0050] The raw water inlet of the second membrane unit is arranged on the fourth side close to the first side;

[0051] The wastewater outlet of the third membrane unit is arranged on the third side close to the first side.

[0052] In a preferred embodiment, two of the first membrane unit, the second membrane unit and the third membrane unit are stacked in the unfolded state of the membrane element, and the other membrane unit is arranged along the extension direction of the water collecting pipe with the two stacked membrane units. When the two stacked membrane units are wound in the water collecting pipe, a water barrier is provided between the side surfaces of the two membrane units and the side surface of the other membrane unit to isolate the connection between the side surfaces of the two membrane units from the side surface of the other membrane unit.

[0053] In a preferred embodiment, the first membrane unit and the second membrane unit are stacked when the membrane element is unfolded, the third membrane unit and the stacked first membrane unit and the second membrane unit are arranged along the extension direction of the water collecting pipe, and the water barrier isolates the wastewater outlet of the first membrane unit, the second membrane unit and the third membrane unit.

[0054] In a preferred embodiment, the first membrane unit and the second membrane unit have a first end and a second end opposite to the first end in the unfolded state, and the third membrane unit has a third end and a fourth end opposite to the third end in the unfolded state, and the first end and the fourth end are in opposite directions;

[0055] The raw water inlet of the first membrane unit is located at the first end when deployed;

[0056] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed;

[0057] The wastewater outlet of the second membrane unit is located at the second end when deployed;

[0058] The raw water inlet of the third membrane unit is located at the third end when deployed; the waste water outlet of the third membrane unit is located at the second side when deployed;

[0059] The raw water inlet of the first membrane unit is arranged at the first end close to the first side;

[0060] The wastewater outlet of the second membrane unit is arranged at the second end close to the first side;

[0061] The raw water inlet of the third membrane unit is arranged at the third end close to the first side.

[0062] In a preferred embodiment, the second membrane unit and the third membrane unit are stacked when the membrane element is unfolded, the first membrane unit and the stacked second membrane unit and the third membrane unit are arranged along the extension direction of the water collecting pipe, and the water barrier isolates the filtered water side of the second membrane unit and the third membrane unit from the raw water inlet of the first membrane unit.

[0063] In a preferred embodiment, the first membrane unit has a first end and a second end opposite to the first end in the unfolded state, and the second membrane unit and the third membrane unit have a third end and a fourth end opposite to the third end in the unfolded state, and the first end and the fourth end are in opposite directions;

[0064] The raw water inlet of the first membrane unit is located at the second side when deployed;

[0065] The wastewater outlet of the first membrane unit is located at the second end when deployed;

[0066] The raw water inlet of the second membrane unit is located at the third end when deployed;

[0067] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed;

[0068] The wastewater outlet of the third membrane unit is located at the fourth end when deployed;

[0069] The wastewater outlet of the first membrane unit is arranged at the second end close to the first side;

[0070] The raw water inlet of the second membrane unit is arranged at the third end close to the first side;

[0071] The wastewater outlet of the third membrane unit is arranged at the fourth end close to the first side.

[0072] In a preferred embodiment, it also includes: a fourth membrane unit wound on the water collecting pipe, the wastewater outlet of the third membrane unit is connected to the raw water inlet of the fourth membrane unit, and when the fourth membrane unit is in the unfolded state, the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the same corresponding side.

[0073] In a preferred embodiment, the first membrane unit and the second membrane unit are stacked when the membrane element is expanded, and the third membrane unit and the fourth membrane unit are stacked when the membrane element is expanded. The stacked first membrane unit and the second membrane unit and the stacked third membrane unit and the fourth membrane unit are arranged along the extension direction of the water collecting pipe, and the connection between the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit is located on the second side, and the first membrane unit, the second membrane unit and the third membrane unit and the fourth membrane unit are isolated by an isolation mechanism.

[0074] In a preferred embodiment, the first membrane unit and the second membrane unit have a first end and a second end opposite to the first end in the unfolded state, and the third membrane unit and the fourth membrane unit have a third end and a fourth end opposite to the third end in the unfolded state, and the first end and the fourth end are in opposite directions;

[0075] The raw water inlet of the first membrane unit is located at the first end when deployed;

[0076] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed;

[0077] The wastewater outlet of the second membrane unit is located at the second end when deployed;

[0078] The raw water inlet of the third membrane unit is located at the third end when deployed; the waste water outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located at the second side when deployed;

[0079] The wastewater outlet of the fourth membrane unit is located at the fourth end when deployed;

[0080] The raw water inlet of the first membrane unit is arranged at the first end close to the first side;

[0081] The wastewater outlet of the second membrane unit is arranged at the second end close to the first side;

[0082] The raw water inlet of the third membrane unit is arranged at the third end close to the first side;

[0083] The wastewater outlet of the fourth membrane unit is arranged at the fourth end close to the first side.

[0084] In a preferred embodiment, the membrane element further includes a water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit. When the membrane element is in an unfolded state, the water-blocking layer is stacked together with the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit.

[0085] In a preferred embodiment, the first membrane unit, the water-blocking layer, the second membrane unit, the third membrane unit and the fourth membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the water-blocking layer, the second membrane unit, the third membrane unit and the fourth membrane unit are stacked in sequence and wound together on the water collecting pipe.

[0086] In a preferred embodiment, the membrane element further has a third side and a fourth side facing each other when in the unfolded state, the third side and the fourth side being connected to the first side and the second side, respectively, and the first membrane unit is located on the outside when the membrane element is in the rolled state;

[0087] The first side of the waterproof layer is sealed with the side of the second side of the first membrane unit close to the second membrane unit, and the side of the second side of the second membrane unit close to the first membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the first membrane unit close to the fourth membrane unit, and the side of the second side of the fourth membrane unit close to the first membrane unit; the second side of the fourth membrane unit is in a sealed state; the side of the second side of the second membrane unit close to the third membrane unit is sealed with the side of the second side of the third membrane unit close to the second membrane unit;

[0088] The raw water inlet of the first membrane unit is located at the second side when deployed;

[0089] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the third side when unfolded;

[0090] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed;

[0091] The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the fourth side when deployed;

[0092] The wastewater outlet of the fourth membrane unit is located on the third side when deployed;

[0093] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are arranged on the third side close to the first side;

[0094] The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are arranged on the fourth side close to the first side;

[0095] The wastewater outlet of the fourth membrane unit is arranged on the third side close to the second side.

[0096] In a preferred embodiment, the first membrane unit, the second membrane unit, the third membrane unit, the water-blocking layer, and the fourth membrane unit are sequentially stacked in the unfolded state of the membrane element, and the first membrane unit, the second membrane unit, the water-blocking layer of the third membrane unit, and the fourth membrane unit are sequentially stacked and wound together on the water collecting pipe;

[0097] The membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, the third side and the fourth side being connected to the first side and the second side respectively, and the fourth membrane unit is located on the outside when the membrane element is in the rolled state;

[0098] The first side of the waterproof layer is sealed with the side of the second side of the fourth membrane unit close to the third membrane unit, and the side of the second side of the third membrane unit close to the fourth membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the fourth membrane unit close to the first membrane unit, and the side of the second side of the first membrane unit close to the fourth membrane unit; the second side of the first membrane unit is in a sealed state; the side of the second side of the second membrane unit close to the third membrane unit is sealed with the side of the second side of the third membrane unit close to the second membrane unit;

[0099] The raw water inlet of the first membrane unit is located on the third side when it is deployed;

[0100] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the fourth side when deployed;

[0101] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed;

[0102] The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the third side when deployed;

[0103] The wastewater outlet of the fourth membrane unit is located at the second side when deployed;

[0104] The raw water inlet of the first membrane unit is arranged on the third side close to the second side;

[0105] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are arranged on the fourth side close to the first side;

[0106] The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are arranged on the third side close to the first side.

[0107] In a preferred embodiment, the first membrane unit, the second membrane unit, the water-blocking layer, the third membrane unit and the fourth membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the second membrane unit, the water-blocking layer, the third membrane unit and the fourth membrane unit are stacked in sequence and wound together on the water collecting pipe.

[0108] In a preferred embodiment, the membrane element further has a third side and a fourth side opposite to each other in the unfolded state, the third side and the fourth side being connected to the first side and the second side respectively, and the fourth membrane unit is located on the outside when the membrane element is in the rolled-up state;

[0109] The first side of the water-proof layer is sealed with a side of the second side of the second membrane unit close to the third membrane unit and a side of the second side of the third membrane unit close to the second membrane unit;

[0110] The second side of the waterproof layer is sealed with a side of the second side of the fourth membrane unit close to the first membrane unit and a side of the second side of the first membrane unit close to the fourth membrane unit;

[0111] The side of the second side of the third membrane unit close to the fourth membrane unit is sealed with the side of the second side of the fourth membrane unit close to the third membrane unit; the side of the second side of the first membrane unit close to the second membrane unit is sealed with the side of the second side of the second membrane unit close to the first membrane unit;

[0112] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed;

[0113] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the fourth side when deployed;

[0114] The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the second side when unfolded.

[0115] In a preferred embodiment, a guide pipe capable of draining wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit; the raw water inlet of the first membrane unit is located on the third side when deployed;

[0116] The raw water inlet of the first membrane unit is arranged on the third side close to the first side;

[0117] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side;

[0118] The flow guide pipe is close to the first side.

[0119] In a preferred embodiment, a flow guide pipe capable of introducing raw water is inserted into the raw water side of the first membrane unit; the wastewater outlet of the fourth membrane unit is located on the third side when deployed;

[0120] The guide pipe is close to the first side;

[0121] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side;

[0122] The wastewater outlet of the fourth membrane unit is arranged on the third side close to the first side.

[0123] In a preferred embodiment, a guide pipe capable of introducing raw water is inserted into the raw water side of the first membrane unit, and a guide pipe capable of discharging waste water from the raw water side is inserted into the raw water side of the fourth membrane unit.

[0124] The flow guide tube in the first membrane unit is close to the first side;

[0125] The flow guide tube in the fourth membrane unit is close to the first side;

[0126] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side.

[0127] In a preferred embodiment, the membrane element further has a third side and a fourth side facing each other when in the unfolded state, the third side and the fourth side being connected to the first side and the second side, respectively, and the first membrane unit is located on the outside when the membrane element is in the rolled state;

[0128] The first side of the water-proof layer is sealed with a side of the second side of the second membrane unit close to the third membrane unit and a side of the second side of the third membrane unit close to the second membrane unit;

[0129] The second side of the waterproof layer is sealed with a side of the second side of the first membrane unit close to the fourth membrane unit and a side of the second side of the fourth membrane unit close to the first membrane unit;

[0130] The side of the second side of the second membrane unit close to the first membrane unit is sealed with the side of the second side of the first membrane unit close to the second membrane unit; the side of the second side of the fourth membrane unit close to the third membrane unit is sealed with the side of the second side of the third membrane unit close to the fourth membrane unit;

[0131] The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed;

[0132] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the fourth side when deployed;

[0133] The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the second side when unfolded.

[0134] In a preferred embodiment, a flow guide pipe capable of introducing raw water is inserted into the raw water side of the first membrane unit; the wastewater outlet of the fourth membrane unit is located on the third side when deployed;

[0135] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side;

[0136] The wastewater outlet of the fourth membrane unit is arranged on the third side close to the first side;

[0137] The flow guide pipe is close to the first side.

[0138] In a preferred embodiment, a guide pipe capable of draining wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit; the raw water inlet of the first membrane unit is located on the third side when deployed;

[0139] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side;

[0140] The wastewater outlet of the fourth membrane unit is arranged on the third side close to the first side;

[0141] The flow guide pipe is close to the first side.

[0142] In a preferred embodiment, a guide pipe capable of introducing raw water is inserted into the raw water side of the first membrane unit, and a guide pipe capable of discharging waste water from the raw water side is inserted into the raw water side of the fourth membrane unit.

[0143] The flow guide tube in the first membrane unit is close to the first side;

[0144] The flow guide tube in the fourth membrane unit is close to the first side;

[0145] The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side.

[0146] In a preferred embodiment, the first membrane unit, the second membrane unit, and the third membrane unit are made of the same or different filter membrane materials.

[0147] In a preferred embodiment, the first membrane unit, the second membrane unit and the third membrane unit are reverse osmosis membranes or nanofiltration membranes.

[0148] In a preferred embodiment, the fourth membrane unit is made of the same or different filter membrane materials.

[0149] In a preferred embodiment, the fourth membrane unit is a reverse osmosis membrane or a nanofiltration membrane.

[0150] In a preferred embodiment, the raw water flow channels of the first membrane unit, the second membrane unit, and the third membrane unit all extend spirally along the circumferential direction of the water collecting pipe.

[0151] In a preferred embodiment, the number of membrane pages in each of the first membrane unit, the second membrane unit and the third membrane unit is different.

[0152] In a preferred embodiment, the number of membrane pages in each of the first membrane unit, the second membrane unit and the third membrane unit decreases in sequence.

[0153] A filter element comprises the membrane element as described in any one of the above items.

[0154] A water purification device comprises the filter element as described above.

[0155] The technical solution of the present invention has the following significant beneficial effects:

[0156] The filtered water flow channel of the membrane element in the present application is divided into more channels, so that the length of each filtered water flow channel formed by the membrane unit and connected to the water collection pipe is further shortened, resulting in a reduction in the back pressure of the membrane unit. Therefore, the water production of the filtered water of the membrane element is further improved to a certain extent. At the same time, under the premise of the same membrane area, due to the reduction in the back pressure of the membrane unit, the length of the raw water flow channel formed in series by the first membrane unit, the second membrane unit, and the third membrane unit in the membrane element can be further increased, and the flow rate of the raw water in the raw water flow channel will be further increased, thereby further increasing the scouring intensity of the raw water on the pollutants attached to the membrane page surface. Therefore, the pollution resistance of the membrane element is further improved and the service life is further extended. Under normal use in ordinary households, the service life of the membrane element under the above structure can reach about five years.

[0157] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope thereby. Within the spirit and scope of the appended claims, the embodiments of the present invention include many variations, modifications, and equivalents. Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0158] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the drawings are merely illustrative and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to specific circumstances under the guidance of the present invention.

[0159] Figure 1 Schematic diagram of the three-dimensional structure of the membrane element in the first embodiment of the present invention in the unfolded state;

[0160] Figure 2 This is a schematic diagram of the flow path principle of the membrane element in the embodiment of the present invention under the first embodiment;

[0161] Figure 3 This is a schematic diagram of the flow path principle of the membrane element in the second embodiment of the present invention;

[0162] Figure 4 Schematic diagram of the three-dimensional structure of the membrane element in the embodiment of the present invention in the unfolded state under the third embodiment;

[0163] Figure 5Schematic diagram of the flow path principle of the membrane element in the third embodiment of the present invention;

[0164] Figure 6 Schematic diagram of the cross section of the membrane element in the third embodiment of the present invention;

[0165] Figure 7 Schematic diagram of the flow path principle of the membrane element in the fourth embodiment of the present invention;

[0166] Figure 8 Schematic diagram of the cross section of a membrane element in a fourth embodiment of the present invention;

[0167] Figure 9 Schematic diagram of the flow path principle of the membrane element in the fifth embodiment of the present invention;

[0168] Figure 10 Schematic diagram of the flow path principle of the membrane element in the sixth embodiment of the present invention;

[0169] Figure 11 Schematic diagram of the flow path principle of the membrane element in the seventh embodiment of the present invention;

[0170] Figure 12 Schematic diagram of the flow path principle of the membrane element in the eighth embodiment of the present invention;

[0171] Figure 13 Schematic diagram of the cross section of the membrane element in the eighth embodiment of the present invention;

[0172] Figure 14 Schematic diagram of the flow path principle of the membrane element in the ninth embodiment of the present invention;

[0173] Figure 15 Schematic diagram of a cross section of a membrane element in a ninth embodiment of the present invention;

[0174] Figure 16 Schematic diagram of the flow path principle of the membrane element in the tenth embodiment of the present invention;

[0175] Figure 17 Schematic diagram of a cross section of a membrane element in a tenth embodiment of the present invention;

[0176] Figure 18 Schematic diagram of the flow path principle of the membrane element in the embodiment of the present invention under the eleventh embodiment;

[0177] Figure 19This is a schematic diagram of the cross section of the membrane element in the eleventh embodiment of the present invention.

[0178] Reference numerals in the above drawings:

[0179] 1. Water collecting pipe; 2. First membrane unit; 3. Second membrane unit; 4. Third membrane unit; 5. Fourth membrane unit; 6. First side; 7. Second side; 8. Third side; 9. Fourth side; 10. Waterproof layer; 11. Isolation mechanism; 12. Waterproof member; 13. First end; 14. Second end; 15. Third end; 16. Fourth end; 17. Flow guide pipe. DETAILED DESCRIPTION

[0180] The details of the present invention can be more clearly understood in conjunction with the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are for illustrative purposes only and are not to be construed as limiting the present invention in any way. Based on the teachings of the present invention, skilled artisans can conceive of any possible variations based on the present invention, all of which should be considered within the scope of the present invention. It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there can be an intermediate element. The terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, internal communication between two elements, direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms based on the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0181] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0182] In order to further improve the flow rate on the raw water side of the membrane element, so as to increase the pollution resistance of the membrane element and thus improve the service life of the membrane element, a membrane element is proposed in the present application. The membrane element may include: a water collecting pipe 1; a first membrane unit 2, a second membrane unit 3 and a third membrane unit 4 wound on the water collecting pipe 1, the wastewater outlet of the first membrane unit 2 is connected to the raw water inlet of the second membrane unit 3, and the wastewater outlet of the second membrane unit 3 is connected to the raw water inlet of the third membrane unit 4; when the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 are in an unfolded state The wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the side at the same position and / or the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the side at the same position; the membrane element has a first side 6 connected to the water collecting pipe 1 and a second side 7 opposite to the first side 6 in the unfolded state, and the second side 7 has at least one of the connecting point between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 and the connecting point between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4.

[0183] When the membrane element in the present application is in the unfolded state, the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 are stacked in sequence, and the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 are wound together on the water collecting pipe 1. The first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 are connected in series through the side edges at the same position of the membrane unit. In particular, after there is at least one of the connection points between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 and the connection points between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 on the second side 7, it can be ensured that the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 have sufficient sides to meet the number of series connections between the three membrane units, the wastewater outlet of the third membrane unit 4, and the raw water inlet of the first membrane unit 2, thereby achieving the series connection requirements of the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4.

[0184] Through the above structure, the filtered water flow path in the membrane element is divided into more channels. The length of each filtered water flow path formed by the membrane unit and connected to the water collection pipe 1 is further shortened, resulting in a reduction in the back pressure of the membrane unit. Therefore, the water output of the membrane element is further increased to a certain extent. At the same time, under the premise of the same membrane area, due to the reduction in the back pressure of the membrane unit, the length of the raw water flow path formed by the first membrane unit 2, the second membrane unit 3, and the third membrane unit 4 in the membrane element in series is further increased. The flow rate of the raw water in the raw water flow path will be further increased, thereby further increasing the intensity of the raw water's scouring of pollutants attached to the membrane surface. Therefore, the pollution resistance of the membrane element is further improved and the service life is further extended. Under normal use in an ordinary household, the service life of the membrane element with the above structure can reach about five years.

[0185] In the above structure, as a preference, the raw water inlet and wastewater outlet of each membrane unit may not be located on the same side. In this structure, water flowing in from the raw water inlet cannot flow along this side to the wastewater outlet. This can fully utilize the raw water side of the membrane unit, thereby maximizing the length of the raw water flow channel and effectively avoiding a decrease in the water production on the filtered water side of the membrane unit. Secondly, the membrane element also has a third side 8 and a fourth side 9 relative to each other in the unfolded state. The third side 8 and the fourth side 9 are connected to the first side 6 and the second side 7 respectively. Since the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 need to be connected in series, the raw water inlet of the first membrane unit 2, the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4, and the wastewater outlet of the third membrane unit 4 need to be provided on the second side 7, the third side 8 and the fourth side 9 of the entire membrane element. At the same time, it is also necessary to make the raw water on the same membrane unit The inlet and the wastewater outlet are not located on the same side. On the basis of the above requirements, the second side 7 of the membrane element in the unfolded state has at least one of the connection points between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, and the connection points between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4. In addition, the wastewater outlets and raw water inlets of the remaining corresponding membrane units are opened on the third side 8 and the fourth side 9 of the membrane element. In this way, while making full use of the raw water side of the membrane unit to maximize the length of the raw water flow channel, it can also ensure that the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 are connected in series.

[0186] In order to better understand the membrane element in this application, it will be further explained and illustrated below. Figure 1 Schematic diagram of the three-dimensional structure of the membrane element in the first embodiment of the present invention in the unfolded state, Figure 2FIG. 1 is a schematic diagram of the flow path principle of the membrane element in the first embodiment of the present invention, as shown in FIG. Figure 1 and Figure 2 As shown, in this embodiment, when the membrane element is in the wound state, the third membrane unit 4 is located on the outside. When in the unfolded state, the membrane element further comprises opposing third and fourth sides 8 and 9, which are connected to the first and second sides 6 and 7, respectively. The raw water inlet of the first membrane unit 2 and the wastewater outlet of the third membrane unit 4 are located on the third side 8 when unfolded; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the second side 7 when unfolded; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the fourth side 9 when unfolded. The raw water inlet of the first membrane unit 2 is located on the third side 8, close to the first side 6; the wastewater outlet of the second membrane unit 3 is located on the fourth side 9, close to the first side 6; the raw water inlet of the third membrane unit 4 is located on the fourth side 9, close to the first side 6; and the wastewater outlet of the third membrane unit 4 is located on the third side 8, close to the second side 7.

[0187] like Figure 1 and Figure 2As shown, the third side 8 of the membrane element, except for the raw water inlet of the first membrane unit 2 and the wastewater outlet of the third membrane unit 4, is sealed by gluing or other methods. The fourth side 9 of the membrane element, except for the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4, is sealed by gluing or other methods. The second side 7 of the first membrane unit 2 in the membrane element, which is adjacent to the second membrane unit 3, is sealed to the second side 7 of the second membrane unit 3, which is adjacent to the first membrane unit 2. The second side 7 of the second membrane unit 3 in the membrane element, which is adjacent to the third membrane unit 4, is sealed to the second side 7 of the third membrane unit 4, which is adjacent to the second membrane unit 3. The second side 7 of the third membrane unit 4 in the membrane element is sealed by gluing or other methods. When the membrane element is wound on the water collection pipe 1, the second side 7 of the first membrane unit 2 in the membrane element, which is adjacent to the third membrane unit 4, is sealed to the second side 7 of the third membrane unit 4. This isolates the filtered water side of the membrane element from the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3. Raw water flows from the raw water inlet of the first membrane unit 2 on the third side 8 near the first side 6 into the raw water side of the first membrane unit 2, passes through the wastewater outlet of the first membrane unit 2 on the second side 7, flows into the raw water inlet of the second membrane unit 3 on the second side 7, passes through the raw water side of the second membrane unit 3, and then flows out from the wastewater outlet of the second membrane unit 3 on the fourth side 9. Then, it flows into the raw water inlet of the third membrane unit 4 on the fourth side 9. After passing through the raw water side of the third membrane unit 4, because the second side 7 of the third membrane unit 4 is in a sealed state, it finally flows out from the wastewater outlet of the third membrane unit 4 on the third side 8 near the second side 7. The filtered water on the filtered water side of the membrane unit flows into the water collection pipe 1 through the various channels in the filtered water flow channel.

[0188] In the above embodiment, when an end cover is provided at the third side 8 of the membrane element, the end cover has two ports, one of which is located on the inner side of the end cover and is connected to the raw water inlet of the first membrane unit 2, and the other port is located on the outer side of the end cover and is connected to the wastewater outlet of the third membrane unit 4.

[0189] Figure 3 FIG. 1 is a schematic diagram of the flow path principle of the membrane element in the second embodiment of the present invention, as shown in FIG. Figure 3As shown, in this embodiment, when the membrane element is in a wound state, the first membrane unit 2 is located on the outside; the raw water inlet of the first membrane unit 2 and the wastewater outlet of the third membrane unit 4 are located on the third side 8 when unfolded; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the fourth side 9 when unfolded; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the second side 7 when unfolded; the raw water inlet of the first membrane unit 2 is arranged on the third side 8 close to the second side 7; the wastewater outlet of the first membrane unit 2 is arranged on the fourth side 9 close to the first side 6; the raw water inlet of the second membrane unit 3 is arranged on the fourth side 9 close to the first side 6; the wastewater outlet of the third membrane unit 4 is arranged on the third side 8 close to the first side 6.

[0190] like Figure 3 As shown, the third side 8 of the membrane element is sealed by gluing or other methods, except for the wastewater outlet of the third membrane unit 4 and the raw water inlet of the first membrane unit 2. The fourth side 9 of the membrane element is sealed by gluing or other methods, except for the raw water inlet of the second membrane unit 3 and the wastewater outlet of the first membrane unit 2. The second side 7 of the third membrane unit 4 in the membrane element, which is adjacent to the second membrane unit 3, is sealed to the second side 7 of the second membrane unit 3, which is adjacent to the first membrane unit 2. The second side 7 of the second membrane unit 3 in the membrane element, which is adjacent to the first membrane unit 2, is sealed to the second side 7 of the first membrane unit 2, which is adjacent to the second membrane unit 3. The second side 7 of the first membrane unit 2 in the membrane element is sealed by gluing or other methods. When the membrane element is wound on the water collection pipe 1, the second side 7 of the third membrane unit 4, which is adjacent to the first membrane unit 2, is sealed to the second side 7 of the first membrane unit 2. This isolates the filtered water side of the membrane element from the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4. Because the second side 7 of the first membrane unit 2 is sealed, raw water flows from the raw water inlet of the first membrane unit 2, located on the third side 8 near the second side 7, into the raw water side of the first membrane unit 2, passes through the wastewater outlet of the first membrane unit 2, located on the fourth side 9 near the first side 6, flows into the raw water inlet of the second membrane unit 3, located on the fourth side 9 near the first side 6, passes through the raw water side of the second membrane unit 3, and then flows out of the wastewater outlet of the second membrane unit 3 located on the second side 7. It then flows into the raw water inlet of the third membrane unit 4 located on the second side 7, passes through the raw water side of the third membrane unit 4, and finally flows out of the wastewater outlet of the third membrane unit 4 located on the third side 8 near the first side 6. The filtered water on the filtered water side of the membrane units then flows into the water collection pipe 1 through the various channels in the filtered water flow channel.

[0191] In the above embodiment, when an end cover is provided at the third side 8 of the membrane element, the end cover has two ports, one of which is located on the outside of the end cover and is connected to the raw water inlet of the first membrane unit 2, and the other port is located on the inside of the end cover and is connected to the wastewater outlet of the third membrane unit 4.

[0192] In the present application, the membrane element may also include a waterproof layer 10 wound on the water collecting pipe 1 together with the first membrane unit 2, the second membrane unit 3 and / or the third membrane unit 4. The membrane element is in an unfolded state, and the waterproof layer 10 is stacked together with the first membrane unit 2, the second membrane unit 3 and part of the membrane units in the third membrane unit 4; the second side 7 also has one of the raw water inlet of the first membrane unit 2 and the wastewater outlet of the third membrane unit 4.

[0193] For example, Figure 4 FIG. 1 is a schematic diagram of a three-dimensional structure of a membrane element in an embodiment of the present invention in a third embodiment in an unfolded state, as shown in FIG. Figure 4 As shown, in this embodiment, the first membrane unit 2, the second membrane unit 3, the water-proof layer 10 and the third membrane unit 4 are stacked in sequence when the membrane element is unfolded, and the first membrane unit 2, the second membrane unit 3, the water-proof layer 10 and the third membrane unit 4 are stacked in sequence and wound together on the water collecting pipe 1. Figure 5 This is a schematic diagram of the flow path principle of the membrane element in the third embodiment of the present invention. Figure 6 FIG. 1 is a schematic diagram of a cross section of a membrane element in an embodiment of the present invention in a third embodiment. Figure 5 and Figure 6 As shown, when the membrane element is in a wound state, the third membrane unit 4 is located on the outside; the first side 6 of the water-proof layer 10 is sealed with the side of the second side 7 of the second membrane unit 3 close to the third membrane unit 4 and the side of the second side 7 of the third membrane unit 4 close to the second membrane unit 3, and the second side 7 of the water-proof layer 10 is sealed with the side of the second side 7 of the third membrane unit 4 close to the first membrane unit 2 and the side of the second side 7 of the first membrane unit 2 close to the third membrane unit 4; the side of the second side 7 of the first membrane unit 2 close to the second membrane unit 3 is sealed with the side of the second side 7 of the second membrane unit 3 close to the first membrane unit 2; at the same time, the third side 8 of the membrane element is sealed by gluing or the like except for the raw water inlet of the first membrane unit 2; the fourth side 9 of the membrane element is sealed by gluing or the like except for the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4. The above method realizes the mutual isolation of the wastewater outlet of the third membrane unit 4, the filtered water side of the membrane element, the connection point between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3.

[0194] like Figure 5As shown, the raw water inlet of the first membrane unit 2 is located on the third side 8 when deployed; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the second side 7 when deployed; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the fourth side 9 when deployed; and the wastewater outlet of the third membrane unit 4 is located on the second side 7 when deployed. The raw water inlet of the first membrane unit 2 is arranged on the third side 8 close to the first side 6; the wastewater outlet of the second membrane unit 3 is arranged on the fourth side 9 close to the first side 6; and the raw water inlet of the third membrane unit 4 is arranged on the fourth side 9 close to the first side 6. Preferably, the wastewater outlet of the third membrane unit 4 is arranged on the second side 7. This approach maximizes the raw water flow path length of the membrane element. The operating principle of the membrane element in this embodiment is as follows: raw water flows in from the raw water inlet of the first membrane unit 2 located on the third side 8 near the first side 6, passes through the raw water side of the first membrane unit 2, and due to the presence of the water barrier 10, flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 located on the second side 7. Then, it flows out of the second membrane unit 3 through the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 located on the third side 8 near the first side 6, flows into the third membrane unit 4, and is finally discharged from the wastewater outlet of the third membrane unit 4 located on the second side 7. The filtered water on the filtered water side of the membrane unit flows into the water collection pipe 1 through various channels in the filtered water flow channel.

[0195] Figure 7 This is a schematic diagram of the flow path principle of the membrane element in the fourth embodiment of the present invention.

[0196] Figure 8 FIG. 1 is a schematic diagram of a cross section of a membrane element in an embodiment of the present invention in a fourth embodiment. Figure 7 、 Figure 8 As shown, in this embodiment, the first membrane unit 2, the water-proof layer 10, the second membrane unit 3 and the third membrane unit 4 are stacked in sequence when the membrane element is unfolded, and the first membrane unit 2, the water-proof layer 10, the second membrane unit 3 and the third membrane unit 4 are stacked in sequence and wound together on the water collecting pipe 1.

[0197] In the above embodiment, if Figure 8As shown, when the membrane element is in the wound state, the first membrane unit 2 is located on the outside. It should be noted that the sponge-like ring in all figures represents a seal by gluing or other means. The sponge-like ring seal of the membrane unit in the figure is only for illustration. The seal can be at the side of the membrane unit, in which case the utilization rate of the membrane unit is higher, or it can be at other locations near the side of the membrane unit, in which case the utilization rate of the membrane unit is slightly lower than that of the previous case. The first side 6 of the water-blocking layer 10 is sealed with the side of the second side 7 of the second membrane unit 3 that is adjacent to the first membrane unit 2, and the side of the second side 7 of the first membrane unit 2 that is adjacent to the second membrane unit 3. The second side 7 of the water-blocking layer 10 is sealed with the side of the second side 7 of the first membrane unit 2 that is adjacent to the third membrane unit 4, and the side of the second side 7 of the third membrane unit 4 that is adjacent to the first membrane unit 2. The side of the second side 7 of the third membrane unit 4 that is adjacent to the second membrane unit 3 is sealed with the side of the second side 7 of the second membrane unit 3 that is adjacent to the third membrane unit 4. Simultaneously, the third side 8 of the membrane element, except for the wastewater outlet of the third membrane unit 4, is sealed by gluing or other means. The fourth side 9 of the membrane element, except for the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, is sealed by gluing or other means. This method achieves mutual isolation between the raw water inlet of the first membrane unit 2, the filtered water side of the membrane element, and the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4.

[0198] like Figure 7 As shown, the raw water inlet of the first membrane unit 2 is located at the second side 7 when deployed; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located at the fourth side 9 when deployed; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located at the second side 7 when deployed; the wastewater outlet of the third membrane unit 4 is located at the third side 8 when deployed; the wastewater outlet of the first membrane unit 2 is set at the fourth side 9 close to the first side 6; the raw water inlet of the second membrane unit 3 is set at the fourth side 9 close to the first side 6; and the wastewater outlet of the third membrane unit 4 is set at the third side 8 close to the first side 6. This method can maximize the raw water flow path length of the membrane element.

[0199] The operating principle of the membrane element in this embodiment is as follows: raw water flows into the raw water inlet of the first membrane unit 2 on the second side 7, passes through the raw water side of the first membrane unit 2, and then flows out of the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 on the third side 8 near the first side 6. Then, due to the presence of the water barrier 10, it flows into the second membrane unit 3 through the connection between the wastewater outlet of the second membrane unit 3 on the second side 7 and the raw water inlet of the third membrane unit 4, and finally is discharged through the wastewater outlet of the third membrane unit 4 on the third side 8 near the first side 6. The filtered water on the filtered water side of the membrane unit flows into the water collection pipe 1 through various channels in the filtered water flow channel.

[0200] In another feasible solution, two membrane units among the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 are stacked in the expanded state of the membrane elements, and another membrane unit is arranged along the extension direction of the water collecting pipe 1 with the two stacked membrane units. When the two stacked membrane units are wound in the water collecting pipe 1, a water barrier 12 is provided between the side surfaces of the two membrane units and the side surfaces of the other membrane unit, so as to isolate the connection between the side surfaces of the two membrane units from the side surfaces of the other membrane unit. The water barrier 12 can be a physical structural member provided between the side surfaces of the two membrane units and the side surfaces of the other membrane unit; or it can be a waterproof tape, which can be used to wrap the side surfaces of the two membrane units and the side surfaces of the other membrane unit, thereby achieving the purpose of isolation. The following are two implementation methods of the above solution:

[0201] For example, Figure 9 FIG. 1 is a schematic diagram of the flow path principle of the membrane element in the fifth embodiment of the present invention, as shown in FIG. Figure 9As shown, in this embodiment, the first membrane unit 2 and the second membrane unit 3 are stacked in the expanded state of the membrane elements, and the third membrane unit 4 is arranged along the extension direction of the water collecting pipe 1 with the stacked first membrane unit 2 and the second membrane unit 3, and the water barrier 12 isolates the first membrane unit 2, the second membrane unit 3 and the wastewater outlet of the third membrane unit 4. Specifically, the first membrane unit 2 and the second membrane unit 3 have a first end 13 and a second end 14 opposite to the first end 13 in the expanded state, and the third membrane unit 4 has a third end 15 and a fourth end 16 opposite to the third end 15 in the expanded state, and the first end 13 and the fourth end 16 are in opposite directions; the raw water inlet of the first membrane unit 2 is located at the first end 13 when expanded; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located at the second side 7 when expanded; the wastewater outlet of the second membrane unit 3 is located at the second end 14 when expanded. The raw water inlet of the third membrane unit 4 is located at the third end 15 when deployed. The second end 14 of the second membrane unit 3 and the third end of the third membrane unit 4 are approximately on the same side, and are considered to be the same side here. The wastewater outlet of the third membrane unit 4 is located at the second side 7 when deployed. The raw water inlet of the first membrane unit 2 is located at the first end 13 near the first side 6. The wastewater outlet of the second membrane unit 3 is located at the second end 14 near the first side 6. The raw water inlet of the third membrane unit 4 is located at the third end 15 near the first side 6. This method maximizes the raw water flow path length of the membrane element. The first ends 13 of the first and second membrane units 2, 3, except for the raw water inlet of the first membrane unit 2, are sealed by adhesive. The second ends 14 of the first and second membrane units 2, 3, except for the wastewater outlet of the second membrane unit 3, are sealed by adhesive. The third end 15 of the third membrane unit 4, except for the raw water inlet of the third membrane unit 4, is sealed by adhesive. The fourth end 16 of the third membrane unit 4 is also sealed by adhesive.

[0202] The operating principle of the membrane element in this embodiment is as follows: raw water flows into the first membrane unit 2 from the raw water inlet of the first membrane unit 2, located near the first end 13 of the first side 6, passes through the raw water side of the first membrane unit 2, and then flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, located near the second side 7. Water flowing out of the wastewater outlet of the first membrane unit 2 flows into the raw water inlet of the second membrane unit 3. Water flowing into the raw water inlet of the second membrane unit 3 passes through the raw water side of the second membrane unit 3 and then flows out of the wastewater outlet of the second membrane unit 3, located near the second end 14 of the first side 6. Because the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located at the same position but on different sides, water flowing out of the wastewater outlet of the second membrane unit 3 can flow into the raw water inlet of the third membrane unit 4, pass through the raw water side of the third membrane unit 4, and ultimately be discharged through the wastewater outlet of the third membrane unit 4, located on the second side 7. The filtered water on the filtered water side of the membrane unit flows into the water collecting pipe 1 through different filtered water flow channels.

[0203] In another embodiment, Figure 10 FIG. 1 is a schematic diagram of the flow path principle of the membrane element in the sixth embodiment of the present invention, as shown in FIG. Figure 10As shown, the second membrane unit 3 and the third membrane unit 4 are stacked in the expanded state of the membrane elements, and the first membrane unit 2 and the stacked second membrane unit 3 and third membrane unit 4 are arranged along the extension direction of the water collecting pipe 1. The water barrier 12 isolates the second membrane unit 3 and the third membrane unit 4 from the raw water inlet of the first membrane unit 2. The first membrane unit 2 has a first end 13 and a second end 14 opposite to the first end 13 in the expanded state. The second membrane unit 3 and the third membrane unit 4 have a third end 15 and a fourth end 16 opposite to the third end 15 in the expanded state. The first end 13 and the fourth end 16 are in opposite directions. The raw water inlet of the first membrane unit 2 is located at the second side 7 when expanded. The wastewater outlet of the first membrane unit 2 is located at the second end 14 when expanded. The raw water inlet of the second membrane unit 3 is located at the third end 15 when expanded. Here, the second end of the first membrane unit 2 14 is adjacent to the third end 15 of the second membrane unit 3 and is therefore considered to be at the same side. The wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located at the second side 7 when deployed. The wastewater outlet of the third membrane unit 4 is located at the fourth end 16 when deployed. The wastewater outlet of the first membrane unit 2 is located at the second end 14 close to the first side 6. The raw water inlet of the second membrane unit 3 is located at the third end 15 close to the first side 6. The wastewater outlet of the third membrane unit 4 is located at the fourth end 16 close to the first side 6. This approach maximizes the raw water flow path length of the membrane element. The third ends 15 of the second membrane unit 3 and the third membrane unit 4 are sealed by gluing except for the raw water inlet of the second membrane unit 3, and the fourth ends 16 of the second membrane unit 3 and the third membrane unit 4 are sealed by gluing except for the wastewater outlet of the third membrane unit 4; the second end 14 of the first membrane unit 2 is sealed by gluing except for the wastewater outlet of the first membrane unit 2; the first end 13 of the first membrane unit 2 is sealed by gluing.

[0204] The operating principle of the membrane element in this embodiment is as follows: raw water flows into the first membrane unit 2 from the raw water inlet located on the second side 7 , passes through the raw water side of the first membrane unit 2 , and then flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 near the first side 6 . Because the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located at the same position but on different sides, water flowing out of the wastewater outlet of the first membrane unit 2 can flow into the raw water inlet of the second membrane unit 3. Water flowing into the raw water inlet of the second membrane unit 3 passes through the raw water side of the second membrane unit 3 and then flows into the third membrane unit 4 through the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 located on the second side 7 . After passing through the raw water side of the third membrane unit 4 , the water is ultimately discharged through the wastewater outlet of the third membrane unit 4 located near the first side 6 .

[0205] In other feasible solutions, the membrane element may further include: a fourth membrane unit 5 wound on the water collecting pipe 1, wherein the wastewater outlet of the third membrane unit 4 is connected to the raw water inlet of the fourth membrane unit 5, and when the fourth membrane unit 5 is in the unfolded state, the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located on the same corresponding side. The following are various implementations of the above solution:

[0206] Figure 11 FIG. 1 is a schematic diagram of the flow path principle of the membrane element in the seventh embodiment of the present invention, as shown in FIG. Figure 11 As shown, in this embodiment, the first membrane unit 2 and the second membrane unit 3 are stacked in the expanded state of the membrane elements, and the third membrane unit 4 and the fourth membrane unit 5 are stacked in the expanded state of the membrane elements. The stacked first membrane unit 2 and the second membrane unit 3 and the stacked third membrane unit 4 and the fourth membrane unit 5 are arranged along the extension direction of the water collecting pipe 1, and the connection point between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 is located on the second side 7, and the first membrane unit 2, the second membrane unit 3 and the third membrane unit 4 and the fourth membrane unit 5 are isolated by the isolation mechanism 11. Specifically, the first membrane unit 2 and the second membrane unit 3 have a first end 13 and a second end 14 opposite to the first end 13 in the unfolded state, and the third membrane unit 4 and the fourth membrane unit 5 have a third end 15 and a fourth end 16 opposite to the third end 15 in the unfolded state, and the first end 13 and the fourth end 16 are in opposite directions; the raw water inlet of the first membrane unit 2 is located at the first end 13 when unfolded; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located at the second side 7 when unfolded; the wastewater outlet of the second membrane unit 3 is located at the second end 14 when unfolded; the third membrane unit 4 and the fourth membrane unit 5 are located at the second end 15 when unfolded. The raw water inlet of the membrane element 4 is located at the third end 15 when deployed; the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located at the second side 7 when deployed; the wastewater outlet of the fourth membrane unit 5 is located at the fourth end 16 when deployed; the raw water inlet of the first membrane unit 2 is located at the first end 13 close to the first side 6; the wastewater outlet of the second membrane unit 3 is located at the second end 14 close to the first side 6; the raw water inlet of the third membrane unit 4 is located at the third end 15 close to the first side 6; and the wastewater outlet of the fourth membrane unit 5 is located at the fourth end 16 close to the first side 6. This approach maximizes the raw water flow path length of the membrane element.

[0207] In the above embodiment, the first ends 13 of the first membrane unit 2 and the second membrane unit 3 are sealed by gluing or the like except for the raw water inlet of the first membrane unit 2; the second ends 14 of the first membrane unit 2 and the second membrane unit 3 are sealed by gluing or the like except for the waste water inlet of the second membrane unit 3; the third ends 15 of the third membrane unit 4 and the fourth membrane unit 5 are sealed by gluing or the like except for the raw water inlet of the third membrane unit 4; the fourth ends 16 of the third membrane unit 4 and the fourth membrane unit 5 are sealed by gluing or the like except for the waste water outlet of the fourth membrane unit 5; the second side edge 7 of the first membrane unit 2 close to the second membrane unit 3 is sealed with the second side edge 7 of the second membrane unit 3 close to the first membrane unit 2, and the second side edge 7 of the third membrane unit 4 close to the fourth membrane unit 5 is sealed with the second side edge 7 of the fourth membrane unit 5 close to the third membrane unit 4 Sealing; when the membrane unit is wound on the water collecting pipe 1, the second side 7 of the first membrane unit 2 is wound around one side of the water collecting pipe 1 for one more time to cover the second membrane unit 3 and then sealed with the side outside the second side 7 of the second membrane unit 3. Preferably, the side outside the second side 7 of the second membrane unit 3 can be sealed with the outside of the first membrane unit 2; the second side 7 of the third membrane unit 4 is wound around one side of the water collecting pipe 1 for one more time to cover the fourth membrane unit 5 and then sealed with the side outside the second side 7 of the fourth membrane unit 5. Preferably, the side outside the second side 7 of the fourth membrane unit 5 can be sealed with the outside of the third membrane unit 4. In this way, the filtered water side of the membrane element is isolated from the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, and the filtered water side of the membrane element is isolated from the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5.

[0208] The operating principle of the membrane element in this embodiment is as follows: raw water flows into the first membrane unit 2 from the raw water inlet of the first membrane unit 2, located at the first end 13 near the first side 6, passes through the raw water side of the first membrane unit 2, and then flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, located at the second side 7. Water flowing into the raw water inlet of the second membrane unit 3 passes through the raw water side of the second membrane unit 3, and then flows through the wastewater outlet of the second membrane unit 3, located at the second end 14 near the first side 6, into the raw water inlet of the third membrane unit 4, located at the third end 15 near the first side 6. After passing through the raw water side of the third membrane unit 4, the water flows into the fourth membrane unit 5 through the connection between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5, located at the second side 7. After passing through the raw water side of the fourth membrane unit 5, the water is ultimately discharged through the wastewater outlet of the fourth membrane unit 5, located at the fourth end 16 near the first side 6. The filtered water from the first membrane unit 2 and the second membrane unit 3 and the filtered water from the third membrane unit 4 and the fourth membrane unit 5 flow into the water collecting pipe 1 through their respective filtered water flow channels.

[0209] In a feasible embodiment, the membrane element may also include a waterproof layer 10 wound on the water collecting pipe 1 together with the first membrane unit 2, the second membrane unit 3, the third membrane unit 4 and the fourth membrane unit 5. When the membrane element is in an unfolded state, the waterproof layer 10 is stacked together with the first membrane unit 2, the second membrane unit 3, the third membrane unit 4 and the fourth membrane unit 5.

[0210] Figure 12 Schematic diagram of the flow path principle of the membrane element in the eighth embodiment of the present invention.

[0211] Figure 13 FIG. 1 is a schematic diagram of a cross section of a membrane element in an eighth embodiment of the present invention, as shown in FIG. Figure 12 、 Figure 13 As shown, the first membrane unit 2, the water-proof layer 10, the second membrane unit 3, the third membrane unit 4 and the fourth membrane unit 5 are stacked in sequence when the membrane element is unfolded, and the first membrane unit 2, the water-proof layer 10, the second membrane unit 3, the third membrane unit 4 and the fourth membrane unit 5 are stacked in sequence and wound together on the water collecting pipe 1.

[0212] like Figure 13 As shown, when the membrane element is in the wound state, the first membrane unit 2 is located on the outside. The first side 6 of the water-blocking layer 10 is sealed with the side of the second side 7 of the first membrane unit 2 near the second membrane unit 3, and the side of the second side 7 of the second membrane unit 3 near the first membrane unit 2. The second side 7 of the water-blocking layer 10 is sealed with the side of the second side 7 of the first membrane unit 2 near the fourth membrane unit 5, and the side of the second side 7 of the fourth membrane unit 5 near the first membrane unit 2. The second side 7 of the fourth membrane unit 5 is in a sealed state. The side of the second side 7 of the second membrane unit 3 near the third membrane unit 4 is sealed with the side of the second side 7 of the third membrane unit 4 near the second membrane unit 3. At the same time, the second side 7 of the second membrane unit 3 close to the third membrane unit 4 is sealed with the side of the second side 7 of the third membrane unit 4 close to the second membrane unit 3; the second side 7 of the third membrane unit 4 close to the fourth membrane unit 5 is sealed with the second side 7 of the fourth membrane unit 5; the third side 8 of the membrane element is sealed by gluing or other means except for the wastewater outlet of the first membrane unit 2, the raw water inlet of the second membrane unit 3, and the wastewater outlet of the fourth membrane unit 5; the fourth side 9 of the membrane element is sealed by gluing or other means except for the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5.

[0213] In this embodiment, the raw water inlet of the first membrane unit 2 is located on the second side 7 when deployed; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the third side 8 when deployed; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the second side 7 when deployed; the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located on the fourth side 9 when deployed; and the wastewater outlet of the fourth membrane unit 5 is located on the third side 8 when deployed. The wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the third side 8 near the first side 6; the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located on the fourth side 9 near the first side 6; and the wastewater outlet of the fourth membrane unit 5 is located on the third side 8 near the second side 7. This structure ensures that the raw water inlet and wastewater outlet of each membrane unit are not located on the same side, and that up to four membrane units are connected in series.

[0214] The operating principle of the membrane element in this embodiment is as follows: Raw water flows into the first membrane unit 2 from the raw water inlet of the first membrane unit 2 located on the second side 7, passes through the raw water side of the first membrane unit 2, and flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 located on the third side 8 near the first side 6. Water flowing in from the raw water inlet of the second membrane unit 3 passes through the raw water side of the second membrane unit 3 and then flows into the third membrane unit 4 from the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 located on the second side 7. Water then flows in from the raw water inlet of the third membrane unit 4 through the raw water side of the third membrane unit 4 and flows into the fourth membrane unit 5 from the connection between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 located on the fourth side 9 near the first side 6. After passing through the raw water side of the fourth membrane unit 5, the water is ultimately discharged through the wastewater outlet of the fourth membrane unit 5 located on the third side 8 near the second side 7. The filtered water from the membrane unit's filtered water side flows into the water collection pipe 1 through different filtered water flow channels. Due to the properly arranged water-blocking layer 10 in the membrane element and the sealed second side 7 of the fourth membrane unit 5, the raw water inlet of the first membrane unit 2, the wastewater outlet of the second membrane unit 3, and the raw water inlet of the third membrane unit 4, as well as the filtered water sides of the membrane units, are all unable to communicate with each other.

[0215] Figure 14 Schematic diagram of the flow path principle of the membrane element in the ninth embodiment of the present invention. Figure 15 FIG. 1 is a schematic diagram of a cross section of a membrane element in a ninth embodiment of the present invention. Figure 14 and Figure 15As shown, the first membrane unit 2, the second membrane unit 3, the third membrane unit 4, the water-proof layer 10 and the fourth membrane unit 5 are stacked in sequence when the membrane element is unfolded, and the first membrane unit 2, the second membrane unit 3, the third membrane unit 4 water-proof layer 10 and the fourth membrane unit 5 are stacked in sequence and wound together on the water collecting pipe 1.

[0216] like Figure 15 As shown, when the membrane element is in a wound state, the fourth membrane unit 5 is located on the outside. The first side 6 of the water-proof layer 10 is sealed with the side of the second side 7 of the fourth membrane unit 5 close to the third membrane unit 4, and the side of the second side 7 of the third membrane unit 4 close to the fourth membrane unit 5; the second side 7 of the water-proof layer 10 is sealed with the side of the second side 7 of the fourth membrane unit 5 close to the first membrane unit 2, and the side of the second side 7 of the first membrane unit 2 close to the fourth membrane unit 5; the second side 7 of the first membrane unit 2 is in a sealed state; the side of the second side 7 of the second membrane unit 3 close to the third membrane unit 4 is sealed with the side of the second side 7 of the third membrane unit 4 close to the second membrane unit 3 ; At the same time, the second side 7 of the third membrane unit 4 close to the second membrane unit 3 is sealed with the second side 7 of the second membrane unit 3 close to the third membrane unit 4; the second side 7 of the second membrane unit 3 close to the first membrane unit 2 is sealed with the second side 7 of the first membrane unit 2; the third side 8 of the membrane element is sealed by gluing or other means except for the raw water inlet of the first membrane unit 2, the wastewater outlet of the third membrane unit 4, and the raw water inlet of the fourth membrane unit 5; the fourth side 9 of the membrane element is sealed by gluing or other means except for the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3.

[0217] In this embodiment, if Figure 14 As shown, the raw water inlet of the first membrane unit 2 is located on the third side 8 when deployed; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the fourth side 9 when deployed; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the second side 7 when deployed; the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located on the third side 8 when deployed; and the wastewater outlet of the fourth membrane unit 5 is located on the second side 7 when deployed. The raw water inlet of the first membrane unit 2 is located on the third side 8 close to the second side 7; the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the fourth side 9 close to the first side 6; and the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located on the third side 8 close to the first side 6. This method can maximize the raw water flow path length of the membrane element.

[0218] The operating principle of the membrane elements in this embodiment is as follows: Raw water flows into the first membrane unit 2 from the raw water inlet of the first membrane unit 2 located on the third side 8, passes through the raw water side of the first membrane unit 2, and flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 located on the fourth side 9 near the first side 6. Water flowing in from the raw water inlet of the second membrane unit 3 passes through the raw water side of the second membrane unit 3 and then flows into the third membrane unit 4 from the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 located on the second side 7. Water then flows in from the raw water inlet of the third membrane unit 4 through the raw water side of the third membrane unit 4 and flows into the fourth membrane unit 5 from the connection between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 located on the third side 8 near the first side 6. After passing through the raw water side of the fourth membrane unit 5, the water is ultimately discharged through the wastewater outlet of the fourth membrane unit 5 located on the second side 7. The filtered water on the filtered water side of the membrane unit flows into the water collection pipe 1 through different filtered water flow channels. Similarly, due to the rational arrangement of the water barrier 10 in the membrane element and the sealed second side 7 of the first membrane unit 2, the wastewater outlet of the fourth membrane unit 5, the connection points between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4, and the filtered water sides of the membrane units are all unable to communicate with each other.

[0219] Figure 16 Schematic diagram of the flow path principle of the membrane element in the tenth embodiment of the present invention. Figure 17 FIG. 1 is a schematic diagram of a cross section of a membrane element in a tenth embodiment of the present invention, as shown in FIG. Figure 16 and Figure 17 As shown, the first membrane unit 2, the second membrane unit 3, the water-proof layer 10, the third membrane unit 4 and the fourth membrane unit 5 are stacked in sequence when the membrane element is unfolded, and the first membrane unit 2, the second membrane unit 3, the water-proof layer 10, the third membrane unit 4 and the fourth membrane unit 5 are stacked in sequence and wound together on the water collecting pipe 1.

[0220] In the above embodiment, when the membrane element is in the wound state, the fourth membrane unit 5 is located on the outside. Figure 17As shown, the first side 6 of the waterproof layer 10 is sealed with the side of the second side 7 of the second membrane unit 3 close to the third membrane unit 4, and the side of the second side 7 of the third membrane unit 4 close to the second membrane unit 3; the second side 7 of the waterproof layer 10 is sealed with the side of the second side 7 of the fourth membrane unit 5 close to the first membrane unit 2, and the side of the second side 7 of the first membrane unit 2 close to the fourth membrane unit 5; the side of the second side 7 of the third membrane unit 4 close to the fourth membrane unit 5 is sealed with the side of the second side 7 of the fourth membrane unit 5 close to the third membrane unit 4; the side of the second side 7 of the first membrane unit 2 close to the second membrane unit 3 is sealed with the side of the second side 7 of the second membrane unit 3 close to the first membrane unit 2.

[0221] like Figure 16 As shown, the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the second side 7 when unfolded; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the fourth side 9 when unfolded; the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located on the second side 7 when unfolded.

[0222] In an optional embodiment, as Figure 16 As shown, when a guide tube 17 capable of discharging wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit 5, the raw water inlet of the first membrane unit 2 is located on the third side 8 when unfolded; the raw water inlet of the first membrane unit 2 is arranged on the third side 8 close to the first side 6; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are arranged on the fourth side 9 close to the first side 6; the guide tube 17 is close to the first side 6. Raw water flows into the raw water inlet of the first membrane unit 2 at the third side 8 near the first side 6, flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 at the second side 7, then enters the third membrane unit 4 through the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 at the fourth side 9 near the first side 6, and then flows into the fourth membrane unit 5 through the connection between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 at the second side 7, and finally exits the fourth membrane unit 5 through the flow guide 17 near the first side 6. Due to the rational arrangement of the water barrier 10, the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, the connection between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5, the filtered water side of the membrane unit, and the raw water side of the membrane unit are isolated from each other.

[0223] In an optional embodiment, when a flow guide 17 for introducing raw water is inserted into the raw water side of the first membrane unit 2, the wastewater outlet of the fourth membrane unit 5 is located on the third side 8 when deployed; the flow guide 17 is close to the first side 6; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the fourth side 9 close to the first side 6; and the wastewater outlet of the fourth membrane unit 5 is located on the third side 8 close to the first side 6. In this embodiment, the flow path of the membrane element is basically the same as the previous embodiment, the difference being that raw water is introduced into the first membrane unit 2 through the flow guide 17 inserted into the raw water side of the first membrane unit 2, and the wastewater ultimately flows out through the wastewater outlet of the fourth membrane unit 5, which is close to the third side 8 close to the first side 6.

[0224] In an optional embodiment, when a flow guide 17 capable of introducing raw water is inserted into the raw water side of the first membrane unit 2, and a flow guide 17 capable of discharging wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit 5, the flow guide 17 in the first membrane unit 2 is close to the first side 6; the flow guide 17 in the fourth membrane unit 5 is close to the first side 6; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are arranged at the fourth side 9 close to the first side 6. In this embodiment, the flow path of the membrane element is basically the same as that of the previous embodiment, the difference being that raw water is introduced into the first membrane unit 2 by the flow guide 17 inserted into the raw water side of the first membrane unit 2, and wastewater is ultimately discharged by the flow guide 17 inserted into the fourth membrane unit 5 close to the first side 6.

[0225] In the above embodiment, when the membrane element is in the wound state, the first membrane unit 2 is located on the outside. Figure 19 As shown, the first side 6 of the waterproof layer 10 is sealed with the side of the second side 7 of the second membrane unit 3 close to the third membrane unit 4, and the side of the second side 7 of the third membrane unit 4 close to the second membrane unit 3; the second side 7 of the waterproof layer 10 is sealed with the side of the second side 7 of the first membrane unit 2 close to the fourth membrane unit 5, and the side of the second side 7 of the fourth membrane unit 5 close to the first membrane unit 2; the side of the second side 7 of the second membrane unit 3 close to the first membrane unit 2 is sealed with the side of the second side 7 of the first membrane unit 2 close to the second membrane unit 3; the side of the second side 7 of the fourth membrane unit 5 close to the third membrane unit 4 is sealed with the side of the second side 7 of the third membrane unit 4 close to the fourth membrane unit 5.

[0226] like Figure 18 As shown, the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 are located on the second side 7 when unfolded; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the fourth side 9 when unfolded; the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 are located on the second side 7 when unfolded.

[0227] In an optional embodiment, as Figure 18 As shown, when a guide tube 17 for introducing raw water is inserted into the raw water side of the first membrane unit 2, the wastewater outlet of the fourth membrane unit 5 is located on the third side 8 when unfolded; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are arranged on the fourth side 9 close to the first side 6; the wastewater outlet of the fourth membrane unit 5 is arranged on the third side 8 close to the first side 6; the guide tube 17 is close to the first side 6. Raw water is introduced into the raw water side of the first membrane unit 2 from the flow guide 17 near the first side 6, flows into the second membrane unit 3 through the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3 on the second side 7, then enters the third membrane unit 4 through the connection between the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 on the fourth side 9 near the first side 6, and then flows into the fourth membrane unit 5 through the connection between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5 on the second side 7, and finally flows out through the wastewater outlet of the fourth membrane unit 5 on the third side 8 near the first side 6. Due to the rational arrangement of the water barrier 10, the connection between the wastewater outlet of the first membrane unit 2 and the raw water inlet of the second membrane unit 3, the connection between the wastewater outlet of the third membrane unit 4 and the raw water inlet of the fourth membrane unit 5, the filtered water side of the membrane unit, and the raw water side of the membrane unit are isolated from each other.

[0228] In an optional embodiment, when a flow guide 17 capable of discharging wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit 5, the raw water inlet of the first membrane unit 2 is located on the third side 8 when deployed; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are located on the fourth side 9 near the first side 6; the wastewater outlet of the fourth membrane unit 5 is located on the third side 8 near the first side 6; and the flow guide 17 is located near the first side 6. In this embodiment, the flow path of the membrane element is essentially the same as that of the previous embodiment, except that raw water is introduced into the raw water inlet of the first membrane unit 2 near the third side 8 near the first side 6, and wastewater is ultimately discharged through the flow guide 17 inserted into the raw water side of the fourth membrane unit 5.

[0229] In an optional embodiment, when a flow guide 17 capable of introducing raw water is inserted into the raw water side of the first membrane unit 2, and a flow guide 17 capable of discharging wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit 5, the flow guide 17 in the first membrane unit 2 is close to the first side 6; the flow guide 17 in the fourth membrane unit 5 is close to the first side 6; the wastewater outlet of the second membrane unit 3 and the raw water inlet of the third membrane unit 4 are arranged at the fourth side 9 close to the first side 6. In this embodiment, the flow path of the membrane element is basically the same as that of the previous embodiment, the difference being that raw water is introduced into the first membrane unit 2 by the flow guide 17 inserted into the raw water side of the first membrane unit 2 close to the first side 6, and the wastewater is ultimately discharged by the flow guide 17 inserted into the fourth membrane unit 5 close to the first side 6.

[0230] Through the above structure, compared with the membrane element formed by three membrane units in series, the membrane element formed by four membrane units in series has a larger number of filtered water flow channels divided into, and each filtered water flow channel connected to the water collecting pipe 1 is shorter, resulting in a smaller back pressure of the membrane unit. Therefore, the water production of the filtered water of the membrane element is improved to a certain extent; at the same time, under the premise of the same membrane area, the length of the raw water flow channel formed by four membrane units in series is longer, and the flow rate of the raw water in the raw water flow channel will be faster, which will make the membrane element more resistant to pollution.

[0231] In all of the above embodiments, when the membrane element is in a wound state, the raw water flow channels of the first membrane unit 2, the second membrane unit 3, and the third membrane unit 4 all spirally extend along the circumference of the water collection pipe 1. When the membrane element is in an unwound state, a first flow channel is formed on the raw water side of the first membrane unit 2, a second flow channel is formed on the raw water side of the second membrane unit 3, and a third flow channel is formed on the raw water side of the third membrane unit 4. The flow direction of the fluid in the first flow channel is opposite to that of the fluid in the second flow channel, and the flow direction of the fluid in the second flow channel is opposite to that of the fluid in the third flow channel. If the membrane element includes a fourth membrane unit 5, a fourth flow channel is formed on the raw water side of the fourth membrane unit 5, and the flow direction of the fluid in the fourth flow channel is opposite to that of the fluid in the third flow channel.

[0232] The first membrane unit 2, the second membrane unit 3, the third membrane unit 4, and the fourth membrane unit 5 can be made of the same or different filter membrane materials. For example, the first membrane unit 2, the second membrane unit 3, the third membrane unit 4, and the fourth membrane unit 5 can be made of reverse osmosis membranes or nanofiltration membranes. When a nanofiltration membrane is used, the filtered water mentioned above is drinking water containing minerals, the filtered water flow path is the drinking water flow path, and the filtered water side is the drinking water side. When a reverse osmosis membrane is used, the filtered water mentioned above is pure water, the filtered water flow path is the pure water flow path, and the filtered water side is the pure water side. Of course, the materials and quantities of the first membrane unit 2, the second membrane unit 3, the third membrane unit 4, and the fourth membrane unit 5 can be selected according to actual needs and will not be repeated here.

[0233] The number of pages of each membrane unit in the first membrane unit 2, the second membrane unit 3, the third membrane unit 4 and the fourth membrane unit 5 can be two pages, or four pages or more pages. Different pages in the same membrane unit can use different materials or the same material. The specific selection can be made according to actual needs and will not be repeated here.

[0234] In a feasible embodiment, the number of membrane pages in each of the first membrane unit 2, the second membrane unit 3, and the third membrane unit 4 is different. Preferably, the number of membrane pages in each of the first membrane unit 2, the second membrane unit 3, and the third membrane unit 4 decreases in sequence. Considering that the wastewater from the first membrane unit 2 enters the second membrane unit 3, and the wastewater from the second membrane unit 3 enters the third membrane unit 4, and since the first membrane unit 2 produces a portion of drinking water and the second membrane unit 3 produces a portion of drinking water, the amount of water entering the second membrane unit 3 is less than that of the first membrane unit 2, and the amount of water entering the third membrane unit 4 is less than that of the second membrane unit 3. In order to maintain the surface flow rate of the second membrane unit 3 and the third membrane unit 4, the membrane surface area of the first membrane unit 2 is greater than the membrane surface area of the second membrane unit 3, and the membrane surface area of the second membrane unit 3 is greater than the membrane surface area of the third membrane unit 4. That is, the number of membrane pages of the first membrane unit 2 is greater than the number of membrane pages of the second membrane unit 3, and the number of membrane pages of the second membrane unit 3 is greater than the number of membrane pages of the third membrane unit 4.

[0235] In addition, the present application also proposes a filter element and a water purification device, wherein the filter element includes any of the membrane elements described above, and the water purification device includes any of the filter elements described above.

[0236] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for all purposes. The term "essentially consisting of..." describing a combination should include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel features of the combination. The use of the terms "comprising" or "including" to describe the combination of elements, ingredients, parts or steps herein also contemplates an embodiment that is essentially composed of these elements, ingredients, parts or steps. By using the term "may", it is intended to illustrate that any attribute described that "may" include is optional. Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0237] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A membrane element, characterized in that: include: water collection pipes; A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; When the first membrane unit, the second membrane unit and the third membrane unit are in an expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; The membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the unfolded state, and the second side has at least one of a connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and a connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit; A water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit and / or the third membrane unit, the membrane element is in an unfolded state, and the water-blocking layer is stacked together with some membrane units among the first membrane unit, the second membrane unit and the third membrane unit; The second side also has a wastewater outlet of the third membrane unit; the first membrane unit, the second membrane unit, the water-proof layer and the third membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the second membrane unit, the water-proof layer and the third membrane unit are stacked in sequence and wound together on the water collecting pipe; the raw water inlet and wastewater outlet of each membrane unit are not located on the same side; the water-proof layer isolates the wastewater outlet of the third membrane unit, the filtered water side of the membrane element, and the connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit from each other.

2. The membrane element according to claim 1, characterized in that The membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, wherein the third side and the fourth side are connected to the first side and the second side respectively; when the membrane element is in the rolled state, the third membrane unit is located on the outside; The first side of the waterproof layer is sealed with the side of the second side of the second membrane unit close to the third membrane unit and the side of the second side of the third membrane unit close to the second membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the third membrane unit close to the first membrane unit and the side of the second side of the first membrane unit close to the third membrane unit; the side of the second side of the first membrane unit close to the second membrane unit is sealed with the side of the second side of the second membrane unit close to the first membrane unit; The raw water inlet of the first membrane unit is located on the third side when it is deployed; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the fourth side when deployed; The wastewater outlet of the third membrane unit is located at the second side when deployed; The raw water inlet of the first membrane unit is arranged on the third side close to the first side; The wastewater outlet of the second membrane unit is arranged on the fourth side close to the first side; The raw water inlet of the third membrane unit is arranged on the fourth side close to the first side.

3. A membrane element, characterized in that: include: water collection pipes; A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; When the first membrane unit, the second membrane unit and the third membrane unit are in an expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; The membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the unfolded state, and the second side has at least one of a connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and a connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit; A water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit and / or the third membrane unit, the membrane element is in an unfolded state, and the water-blocking layer is stacked together with some membrane units among the first membrane unit, the second membrane unit and the third membrane unit; The second side has a raw water inlet of the first membrane unit; the first membrane unit, the water-blocking layer, the second membrane unit and the third membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the water-blocking layer, the second membrane unit and the third membrane unit are stacked in sequence and wound together on the water collecting pipe; the raw water inlet and the wastewater outlet of each membrane unit are not located on the same side; the water-blocking layer isolates the raw water inlet of the first membrane unit, the filtered water side of the membrane element, the wastewater outlet of the second membrane unit and the connecting point of the raw water inlet of the third membrane unit from each other.

4. The membrane element according to claim 3, characterized in that The membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, wherein the third side and the fourth side are connected to the first side and the second side respectively; when the membrane element is in the rolled state, the first membrane unit is located on the outside; The first side of the waterproof layer is sealed with the side of the second side of the second membrane unit close to the first membrane unit and the side of the second side of the first membrane unit close to the second membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the first membrane unit close to the third membrane unit and the side of the second side of the third membrane unit close to the first membrane unit; the side of the second side of the third membrane unit close to the second membrane unit is sealed with the side of the second side of the second membrane unit close to the third membrane unit; The raw water inlet of the first membrane unit is located at the second side when deployed; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the fourth side when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed; The wastewater outlet of the third membrane unit is located on the third side when deployed; The wastewater outlet of the first membrane unit is arranged at the fourth side close to the first side; The raw water inlet of the second membrane unit is arranged on the fourth side close to the first side; The wastewater outlet of the third membrane unit is arranged on the third side close to the first side.

5. A membrane element, characterized in that: include: water collection pipes; A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; When the first membrane unit, the second membrane unit and the third membrane unit are in an expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; The membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the unfolded state, and the second side has at least one of a connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and a connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit; A water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit and / or the third membrane unit, the membrane element is in an unfolded state, and the water-blocking layer is stacked together with some membrane units among the first membrane unit, the second membrane unit and the third membrane unit; Two of the first membrane unit, the second membrane unit and the third membrane unit are stacked in the unfolded state of the membrane element, and the other membrane unit is arranged along the extension direction of the water collecting pipe with the two stacked membrane units. When the two stacked membrane units are wound in the water collecting pipe, water barriers are provided between the sides of the two membrane units and the side of another membrane unit to isolate the connecting point of the sides of the two membrane units from the side of another membrane unit; the raw water inlet and waste water outlet of each membrane unit are not located on the same side.

6. The membrane element according to claim 5, characterized in that The first membrane unit and the second membrane unit are stacked when the membrane element is unfolded, and the third membrane unit and the stacked first membrane unit and the second membrane unit are arranged along the extension direction of the water collecting pipe, and the water barrier isolates the wastewater outlet of the first membrane unit, the second membrane unit and the third membrane unit.

7. The membrane element according to claim 6, characterized in that The first membrane unit and the second membrane unit have a first end and a second end opposite to the first end in the unfolded state, and the third membrane unit has a third end and a fourth end opposite to the third end in the unfolded state, and the first end and the fourth end are in opposite directions; The raw water inlet of the first membrane unit is located at the first end when deployed; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed; The wastewater outlet of the second membrane unit is located at the second end when deployed; The raw water inlet of the third membrane unit is located at the third end when deployed; the waste water outlet of the third membrane unit is located at the second side when deployed; The raw water inlet of the first membrane unit is arranged at the first end close to the first side; The wastewater outlet of the second membrane unit is arranged at the second end close to the first side; The raw water inlet of the third membrane unit is arranged at the third end close to the first side.

8. The membrane element according to claim 5, characterized in that The second membrane unit and the third membrane unit are stacked when the membrane element is unfolded, and the first membrane unit and the stacked second and third membrane units are arranged along the extension direction of the water collecting pipe, and the water barrier isolates the filtered water side of the second and third membrane units from the raw water inlet of the first membrane unit.

9. The membrane element according to claim 8, characterized in that The first membrane unit has a first end and a second end opposite to the first end in the unfolded state, and the second membrane unit and the third membrane unit have a third end and a fourth end opposite to the third end in the unfolded state, and the first end and the fourth end are in opposite directions; The raw water inlet of the first membrane unit is located at the second side when deployed; The wastewater outlet of the first membrane unit is located at the second end when deployed; The raw water inlet of the second membrane unit is located at the third end when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed; The wastewater outlet of the third membrane unit is located at the fourth end when deployed; The wastewater outlet of the first membrane unit is arranged at the second end close to the first side; The raw water inlet of the second membrane unit is arranged at the third end close to the first side; The wastewater outlet of the third membrane unit is arranged at the fourth end close to the first side.

10. A membrane element, characterized in that: include: water collection pipes; A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; When the first membrane unit, the second membrane unit and the third membrane unit are in an expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; The membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the unfolded state, and the second side has at least one of a connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and a connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit; a fourth membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the third membrane unit is connected to the raw water inlet of the fourth membrane unit, and when the fourth membrane unit is in an unfolded state, the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the same corresponding side; The first membrane unit and the second membrane unit are stacked when the membrane element is unfolded, and the third membrane unit and the fourth membrane unit are stacked when the membrane element is unfolded. The stacked first membrane unit and the second membrane unit and the stacked third membrane unit and the fourth membrane unit are arranged along the extension direction of the water collecting pipe. The connection between the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit is located on the second side. The first membrane unit, the second membrane unit and the third membrane unit and the fourth membrane unit are isolated by an isolation mechanism; the raw water inlet and the wastewater outlet of each membrane unit are not located on the same side.

11. The membrane element according to claim 10, characterized in that The first membrane unit and the second membrane unit have a first end and a second end opposite to the first end in the unfolded state, and the third membrane unit and the fourth membrane unit have a third end and a fourth end opposite to the third end in the unfolded state, and the first end and the fourth end are in opposite directions; The raw water inlet of the first membrane unit is located at the first end when deployed; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed; The wastewater outlet of the second membrane unit is located at the second end when deployed; The raw water inlet of the third membrane unit is located at the third end when deployed; the waste water outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located at the second side when deployed; The wastewater outlet of the fourth membrane unit is located at the fourth end when deployed; The raw water inlet of the first membrane unit is arranged at the first end close to the first side; The wastewater outlet of the second membrane unit is arranged at the second end close to the first side; The raw water inlet of the third membrane unit is arranged at the third end close to the first side; The wastewater outlet of the fourth membrane unit is arranged at the fourth end close to the first side.

12. A membrane element, characterized in that: include: water collection pipes; A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; When the first membrane unit, the second membrane unit and the third membrane unit are in an expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; The membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the unfolded state, and the second side has at least one of a connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and a connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit; a fourth membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the third membrane unit is connected to the raw water inlet of the fourth membrane unit, and when the fourth membrane unit is in an unfolded state, the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the same corresponding side; a water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit, wherein when the membrane element is in an unfolded state, the water-blocking layer and the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit are stacked together; The first membrane unit, the water-proof layer, the second membrane unit, the third membrane unit and the fourth membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the water-proof layer, the second membrane unit, the third membrane unit and the fourth membrane unit are stacked in sequence and wound together on the water collecting pipe; the raw water inlet and the wastewater outlet of each membrane unit are not located on the same side; the water-proof layer makes it impossible for the raw water inlet of the first membrane unit, the wastewater outlet of the second membrane unit and the connecting point of the raw water inlet of the third membrane unit, and the filtered water side of the membrane unit to be connected to each other; the raw water inlet of the first membrane unit and the wastewater outlet of the fourth membrane unit are not located on the same side.

13. The membrane element according to claim 12, characterized in that The membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, wherein the third side and the fourth side are connected to the first side and the second side respectively, and when the membrane element is in the rolled state, the first membrane unit is located on the outside; The first side of the waterproof layer is sealed with the side of the second side of the first membrane unit close to the second membrane unit, and the side of the second side of the second membrane unit close to the first membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the first membrane unit close to the fourth membrane unit, and the side of the second side of the fourth membrane unit close to the first membrane unit; the second side of the fourth membrane unit is in a sealed state; the side of the second side of the second membrane unit close to the third membrane unit is sealed with the side of the second side of the third membrane unit close to the second membrane unit; The raw water inlet of the first membrane unit is located at the second side when deployed; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the third side when unfolded; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed; The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the fourth side when deployed; The wastewater outlet of the fourth membrane unit is located on the third side when deployed; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are arranged on the third side close to the first side; The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are arranged on the fourth side close to the first side; The wastewater outlet of the fourth membrane unit is arranged on the third side close to the second side.

14. A membrane element, characterized in that: include: water collection pipes; A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; When the first membrane unit, the second membrane unit and the third membrane unit are in an expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; The membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the unfolded state, and the second side has at least one of a connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and a connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit; a fourth membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the third membrane unit is connected to the raw water inlet of the fourth membrane unit, and when the fourth membrane unit is in an unfolded state, the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the same corresponding side; a water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit, wherein when the membrane element is in an unfolded state, the water-blocking layer and the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit are stacked together; The first membrane unit, the second membrane unit, the third membrane unit, the water-proof layer and the fourth membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the second membrane unit, the third membrane unit, the water-proof layer and the fourth membrane unit are stacked in sequence and wound together on the water collecting pipe; the raw water inlet and the wastewater outlet of each membrane unit are not located on the same side; the water-proof layer prevents the wastewater outlet of the fourth membrane unit, the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit, and the filtered water side of the membrane unit from being connected to each other; the raw water inlet of the first membrane unit and the wastewater outlet of the fourth membrane unit are not located on the same side.

15. The membrane element according to claim 14, characterized in that The membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, the third side and the fourth side being connected to the first side and the second side respectively, and the fourth membrane unit is located on the outside when the membrane element is in the rolled state; The first side of the waterproof layer is sealed with the side of the second side of the fourth membrane unit close to the third membrane unit, and the side of the second side of the third membrane unit close to the fourth membrane unit; the second side of the waterproof layer is sealed with the side of the second side of the fourth membrane unit close to the first membrane unit, and the side of the second side of the first membrane unit close to the fourth membrane unit; the second side of the first membrane unit is in a sealed state; the side of the second side of the second membrane unit close to the third membrane unit is sealed with the side of the second side of the third membrane unit close to the second membrane unit; The raw water inlet of the first membrane unit is located on the third side when it is deployed; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the fourth side when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the second side when deployed; The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the third side when deployed; The wastewater outlet of the fourth membrane unit is located at the second side when deployed; The raw water inlet of the first membrane unit is arranged on the third side close to the second side; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are arranged on the fourth side close to the first side; The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are arranged on the third side close to the first side.

16. A membrane element, characterized in that: include: water collection pipes; A first membrane unit, a second membrane unit, and a third membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the first membrane unit is connected to the raw water inlet of the second membrane unit, and the wastewater outlet of the second membrane unit is connected to the raw water inlet of the third membrane unit; When the first membrane unit, the second membrane unit and the third membrane unit are in an expanded state, the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the side at the same position, or the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the side at the same position; The membrane element has a first side connected to the water collecting pipe and a second side opposite to the first side in the unfolded state, and the second side has at least one of a connection point between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit and a connection point between the wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit; a fourth membrane unit wound on the water collecting pipe, wherein the wastewater outlet of the third membrane unit is connected to the raw water inlet of the fourth membrane unit, and when the fourth membrane unit is in an unfolded state, the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the same corresponding side; a water-blocking layer wound on the water collecting pipe together with the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit, wherein when the membrane element is in an unfolded state, the water-blocking layer and the first membrane unit, the second membrane unit, the third membrane unit and the fourth membrane unit are stacked together; The first membrane unit, the second membrane unit, the water-proof layer, the third membrane unit and the fourth membrane unit are stacked in sequence when the membrane element is unfolded, and the first membrane unit, the second membrane unit, the water-proof layer, the third membrane unit and the fourth membrane unit are stacked in sequence and wound together on the water collecting pipe; the raw water inlet and the wastewater outlet of each membrane unit are not located on the same side; the water-proof layer isolates the connection between the wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit, the connection between the wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit, the filtered water side of the membrane unit and the raw water side of the membrane unit from each other.

17. The membrane element according to claim 16, characterized in that The membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, the third side and the fourth side being connected to the first side and the second side respectively, and the fourth membrane unit is located on the outside when the membrane element is in the rolled state; The first side of the water-proof layer is sealed with a side of the second side of the second membrane unit close to the third membrane unit and a side of the second side of the third membrane unit close to the second membrane unit; The second side of the waterproof layer is sealed with a side of the second side of the fourth membrane unit close to the first membrane unit and a side of the second side of the first membrane unit close to the fourth membrane unit; The side of the second side of the third membrane unit close to the fourth membrane unit is sealed with the side of the second side of the fourth membrane unit close to the third membrane unit; the side of the second side of the first membrane unit close to the second membrane unit is sealed with the side of the second side of the second membrane unit close to the first membrane unit; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the fourth side when deployed; The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the second side when unfolded.

18. The membrane element according to claim 17, characterized in that A guide pipe capable of guiding wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit; the raw water inlet of the first membrane unit is located on the third side when deployed; The raw water inlet of the first membrane unit is arranged on the third side close to the first side; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side; The flow guide pipe is close to the first side.

19. The membrane element according to claim 17, characterized in that A guide pipe for introducing raw water is inserted into the raw water side of the first membrane unit; the wastewater outlet of the fourth membrane unit is located on the third side when deployed; The guide pipe is close to the first side; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side; The wastewater outlet of the fourth membrane unit is arranged on the third side close to the first side.

20. The membrane element according to claim 17, characterized in that A guide pipe capable of introducing raw water is inserted into the raw water side of the first membrane unit, and a guide pipe capable of discharging waste water from the raw water side is inserted into the raw water side of the fourth membrane unit; The flow guide tube in the first membrane unit is close to the first side; The flow guide tube in the fourth membrane unit is close to the first side; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side.

21. The membrane element according to claim 16, characterized in that The membrane element further comprises a third side and a fourth side opposite to each other in the unfolded state, wherein the third side and the fourth side are connected to the first side and the second side respectively, and when the membrane element is in the rolled state, the first membrane unit is located on the outside; The first side of the water-proof layer is sealed with a side of the second side of the second membrane unit close to the third membrane unit and a side of the second side of the third membrane unit close to the second membrane unit; The second side of the waterproof layer is sealed with a side of the second side of the first membrane unit close to the fourth membrane unit and a side of the second side of the fourth membrane unit close to the first membrane unit; The side of the second side of the second membrane unit close to the first membrane unit is sealed with the side of the second side of the first membrane unit close to the second membrane unit; the side of the second side of the fourth membrane unit close to the third membrane unit is sealed with the side of the second side of the third membrane unit close to the fourth membrane unit; The wastewater outlet of the first membrane unit and the raw water inlet of the second membrane unit are located on the second side when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are located on the fourth side when deployed; The wastewater outlet of the third membrane unit and the raw water inlet of the fourth membrane unit are located on the second side when unfolded.

22. The membrane element according to claim 21, characterized in that A guide pipe for introducing raw water is inserted into the raw water side of the first membrane unit; the wastewater outlet of the fourth membrane unit is located on the third side when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side; The wastewater outlet of the fourth membrane unit is arranged on the third side close to the first side; The flow guide pipe is close to the first side.

23. The membrane element according to claim 21, characterized in that A guide pipe capable of guiding wastewater from the raw water side is inserted into the raw water side of the fourth membrane unit; the raw water inlet of the first membrane unit is located on the third side when deployed; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side; The wastewater outlet of the fourth membrane unit is arranged on the third side close to the first side; The flow guide pipe is close to the first side.

24. The membrane element according to claim 21, characterized in that A guide pipe capable of introducing raw water is inserted into the raw water side of the first membrane unit, and a guide pipe capable of discharging waste water from the raw water side is inserted into the raw water side of the fourth membrane unit; The flow guide tube in the first membrane unit is close to the first side; The flow guide tube in the fourth membrane unit is close to the first side; The wastewater outlet of the second membrane unit and the raw water inlet of the third membrane unit are arranged on the fourth side close to the first side.

25. The membrane element according to any one of claims 1 to 24, characterized in that The first membrane unit, the second membrane unit and the third membrane unit are made of the same or different filter membrane materials.

26. The membrane element according to any one of claims 1 to 24, characterized in that The first membrane unit, the second membrane unit and the third membrane unit are reverse osmosis membranes or nanofiltration membranes.

27. The membrane element according to any one of claims 10 to 24, characterized in that The fourth membrane unit is made of the same or different filter membrane materials.

28. The membrane element according to any one of claims 10 to 24, characterized in that The fourth membrane unit is a reverse osmosis membrane or a nanofiltration membrane.

29. The membrane element according to any one of claims 1 to 24, characterized in that The raw water flow channels of the first membrane unit, the second membrane unit, and the third membrane unit all extend spirally along the circumferential direction of the water collecting pipe.

30. The membrane element according to any one of claims 1 to 24, characterized in that The number of membrane pages in each of the first membrane unit, the second membrane unit and the third membrane unit is different.

31. The membrane element according to any one of claims 1 to 24, characterized in that The number of membrane pages in each of the first membrane unit, the second membrane unit and the third membrane unit decreases in sequence.

32. A filter element, characterized in that: Comprising the membrane element according to any one of claims 1 to 31.

33. A water purification device, characterized in that: Comprising a filter element as described in claim 32.

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