Pre-filter

Abstract

The utility model discloses a prefilter which comprises a shell part and a filter element, the shell part is provided with a water inlet, a water outlet and a drain outlet, the filter element is arranged in the shell part and is matched with the shell part to form a raw water cavity communicated with the drain outlet and a purified water cavity communicated with the water outlet, a water inlet channel is arranged between the water inlet and the raw water cavity, and a water outlet channel is arranged between the water inlet and the purified water cavity. A backwashing channel is arranged between the water inlet and the water purification cavity, and a plugging piece for opening and closing the sewage draining exit is arranged at the sewage draining exit; and the water path switching mechanism is arranged on the shell part and is used for controlling the switching opening of the water inlet channel and the backwashing channel. When the pre-filter disclosed by the utility model is in a filtering state, the backwashing channel is in a closed state, so that if a backwashing filter screen is arranged on the backwashing channel, the backwashing filter screen cannot filter water flow in the filtering state, so that dirt on the backwashing filter screen can be reduced, and normal filtering of the backwashing filter screen in the backwashing state is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of filters, in particular to a pre-filter. Background Art

[0002] The secondary pollution such as pipeline corrosion and sediment in municipal tap water causes the deterioration of the domestic water quality. Usually, a pre-filter is installed on the household pipeline to improve the water quality. After the filter element of the pre-filter is used for a period of time, backwashing is required to clean the filter element and improve the service life of the filter element. Therefore, in addition to an inlet channel provided between the water inlet and the raw water chamber, a backwashing channel is also provided between the water inlet and the purified water chamber of the pre-filter, so that when backwashing is started, the water flow enters the purified water chamber through the backwashing channel, flows to the raw water chamber after reverse flushing of the filter element, and is discharged through the sewage outlet. Since the pre-filter of the prior art usually only sets a switch assembly at the inlet channel to control the opening and closing of the inlet channel, and the backwashing channel is always kept open, in order to prevent the water flow passing through the backwashing channel from directly discharging from the water outlet without filtration, a backwashing filter screen is usually set on the backwashing channel. However, the backwashing filter screen will be soiled by the filtered water flow during the filtering state and even blocked by the dirt, resulting in a decrease in the water volume of the backwashing filter screen and a poor backwashing effect when backwashing is realized again. Summary of the Utility Model

[0003] Aiming at the technical problems existing in the prior art, the utility model provides a pre-filter, which can control the switching opening of the inlet channel and the backwashing channel to avoid the influence of the overwater volume of the backwashing filter screen caused by the opening of the backwashing channel during the filtering state.

[0004] The technical solution adopted by the utility model to solve its technical problems is: a pre-filter, including a housing part and a filter element. The housing part is provided with a water inlet, a water outlet and a sewage outlet. The filter element is installed in the housing part and cooperates with the housing part to form a raw water chamber communicating with the sewage outlet and a purified water chamber communicating with the water outlet. An inlet channel for connecting the two is provided between the water inlet and the raw water chamber, and a backwashing channel for connecting the two is provided between the water inlet and the purified water chamber. A plugging member for opening and closing the sewage outlet is arranged at the sewage outlet; a water path switching mechanism is further included, and the water path switching mechanism is installed on the housing part and controls the switching opening of the inlet channel and the backwashing channel.

[0005] Further, the waterway switching mechanism includes a waterway bracket and a waterway switch. The waterway bracket includes a first water passing part located on the water inlet passage and a second water passing part located on the backwashing passage. The first water passing part is provided with a first water passing hole, and the second water passing part is provided with a second water passing hole. The waterway switch cooperates with the waterway bracket, and the waterway switch is driven by a driving member to rotate, so that the waterway switch controls the switching and opening of the first water passing hole and the second water passing hole through rotation.

[0006] Further, the filter element is cylindrical, the waterway bracket is coaxially arranged with the filter element, the first water passing part is annular and is provided with a plurality of the first water passing holes distributed along its circumferential direction; the second water passing part is cylindrical and is provided with a plurality of the second water passing holes distributed along its circumferential direction.

[0007] Further, the waterway switch includes a third water passing part adapted to the first water passing part and a fourth water passing part adapted to the second water passing part. The third water passing part is provided with a third water passing hole, and the fourth water passing part is provided with a fourth water passing hole. The waterway switch rotates around the axis of the filter element, so that the third water passing hole corresponds to or is staggered from the first water passing hole one by one, and the fourth water passing hole corresponds to or is staggered from the second water passing hole one by one.

[0008] Further, a backwashing filter screen is arranged on the backwashing passage, and the backwashing filter screen is located on the water inlet side of the second water passing part.

[0009] Further, it further includes a swirl member. The swirl member is connected to the water outlet side of the first water passing part. The third water passing part is located between the first water passing part and the swirl member. The swirl member is provided with a plurality of swirl water channels distributed along the same swirl direction. The swirl water channels are inclined water channels or spiral water channels. One end of the swirl water channel corresponds to the first water passing hole one by one, and the other end of the swirl water channel forms a water outlet hole capable of laterally discharging water.

[0010] Further, the driving member is a valve rod. The valve rod is rotatably connected to the housing part around its axis and is relatively fixed to the waterway switch. One end of the valve rod extends out of the housing part, and a flushing knob is arranged. The other end of the valve rod passes through the purified water cavity and is connected to the plugging member, so that the valve rod drives the plugging member to open or close the sewage outlet through rotation.

[0011] Further, the plugging member is sleeved outside the other end of the valve rod and can rotate with the valve rod and axially move relative to the valve rod. The plugging member is provided with an external thread, and the external thread is threadedly connected to an internal thread arranged on a fixed sleeve fixed in the purified water cavity.

[0012] Further, the filter element includes a laminated filter screen, which includes a plurality of superimposed and fitted laminations, and a movable limit seat is provided at one end of the laminated filter screen close to the sewage discharge port. The movable limit seat is pressed by an elastic member so that the plurality of laminations are in a mutually pressed state.

[0013] Further, the filter element further includes a main filter screen, which is located inside the laminated filter screen, and the filtration accuracy of the main filter screen is higher than that of the laminated filter screen. The main filter screen is sleeved outside a filter element support.

[0014] Compared with the prior art, the present utility model has the following beneficial effects:

[0015] 1. Since the present utility model uses a water path switching mechanism to control the switching and opening of the water inlet channel and the backwashing channel, the backwashing channel of the pre-filter of the present utility model is in a closed state during the filtering state. Therefore, if a backwashing filter screen is provided on the backwashing channel, the backwashing filter screen will not filter the water flow during the filtering state, thereby reducing the fouling of the backwashing filter screen and ensuring that the backwashing filter screen can filter normally during the backwashing state and meet the requirements of backwashing.

[0016] 2. The water path switching mechanism preferably includes the water channel support and the water channel switch, so that the present utility model only needs these two parts as the switching main body to realize the water path switching, and has the characteristics of simple structure and convenient installation. In particular, the water channel support is coaxially arranged with the filter element, its first water passing part is annular, and a plurality of the first water passing holes are arranged along its circumferential direction. Its second water passing part is cylindrical, and a plurality of the second water passing holes are arranged along its circumferential direction. The water channel switch includes the third water passing part and the fourth water passing part, so that the water channel support and the water channel switch cooperate with each other, which can not only meet the requirements of water path switching, but also make the overall structure simpler, and the water passing capacity requirements can be met without adding additional components.

[0017] 3. The backwashing filter screen is located on the water inlet side of the second water passing part, so that the backwashing filter screen not only does not filter the water flow during the filtering state, but also enables the surface of the backwashing filter screen to be flushed by the water flow, so that the backwashing filter screen can be flushed, and the fouling of the backwashing filter screen can be further reduced.

[0018] 4. The driving member is a valve rod, and the other end of the valve rod is connected to the blocking member, so that the present utility model only needs one operation action to simultaneously realize the functions of water path switching and opening / closing the sewage discharge port, thereby making the operation of the present utility model more convenient.

[0019] 5. The setting of the swirling water channel enables the water flow to rotate into the raw water cavity when the water inlet channel of the present utility model is opened, so that the surface of the filter element is continuously washed by rotation, and the water flow is always in a disturbed state, making it not easy for the surface of the filter element to be fouled.

[0020] 6. The filter element further includes the main filter screen, enabling the present utility model to adopt a double-layer filter screen for progressive filtration, which can not only greatly improve the filtration effect but also effectively protect the main filter screen, thereby extending the service life of the filter.

[0021] The following further elaborates on the present utility model in conjunction with the accompanying drawings and embodiments; however, a pre-filter of the present utility model is not limited to the embodiments. Description of the Drawings

[0022] Figure 1 is an exploded schematic view of the present utility model;

[0023] Figure 2 is an exploded schematic view of the water path switching mechanism of the present utility model (including the swirl element, excluding the valve stem);

[0024] Figure 3 is a schematic diagram of the cooperation between the filter element and the water path switching mechanism of the present utility model when the water inlet channel is open;

[0025] Figure 4 is a cross-sectional view of the filter element and the water path switching mechanism of the present utility model when the water inlet channel is open;

[0026] Figure 5 is a schematic diagram of the cooperation between the filter element and the water path switching mechanism of the present utility model when the water inlet channel is closed;

[0027] Figure 6 is a cross-sectional view of the filter element and the water path switching mechanism of the present utility model when the water inlet channel is closed;

[0028] Figure 7 is the front view of the present utility model;

[0029] Figure 8 is the cross-sectional view of the present utility model;

[0030] Figure 9 is the cross-sectional view of the present utility model in the filtering state;

[0031] Figure 10 is the cross-sectional view of the present utility model in the backwashing state;

[0032] In the figure, 1 is the housing part; 11 is the inlet and outlet head; 111 is the water inlet; 112 is the water outlet; 12 is the filter housing; 121 is the sewage outlet; 122 is the raw water chamber; 2 is the filter element; 21 is the stacked disc filter screen; 211 are the stacked discs; 22 is the movable limit seat; 23 is the swirl element; 231 is the swirl water channel; 232 is the water outlet hole; 24 is the main filter screen; 25 is the filter element support; 26 is the purified water chamber; 3 is the water channel support; 31 is the first water passing part; 311 is the first water passing hole; 32 is the second water passing part; 321 is the second water passing hole; 4 is the water channel switch; 41 is the third water passing part; 411 is the third water passing hole; 42 is the fourth water passing part; 421 is the fourth water passing hole; 43 is the first tooth; 5 is the spring; 6 is the backwash filter screen; 7 is the plugging member; 8 is the valve rod; 81 is the flushing knob; 82 is the second tooth; 9 is the fixing sleeve. Detailed implementation mode

[0033] In the present utility model, for terms such as "first" and "second", they are only used to distinguish similar objects, rather than to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. In the description, the orientation or positional relationship indicated by "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection scope of the present utility model. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0034] In addition, in the description of the present utility model, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, both A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. In the description of the present utility model, unless otherwise clearly specified and limited, terms such as "installation", "setting", "connection", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection, can be a mechanical connection, can be an electrical connection, can be directly connected, or can be indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0035] Please refer to Figures 1-10As shown, a pre-filter of the utility model comprises a housing part 1 and a filter element 2. The housing part 1 is provided with a water inlet 111, a water outlet 112 and a sewage outlet 121. The filter element 2 is installed in the housing part 1 and cooperates with the housing part 1 to form a raw water chamber 122 connected to the sewage outlet 121 and a clean water chamber 26 connected to the water outlet 112. Specifically, in this embodiment, the filter element 2 is cylindrical, the clean water chamber 26 is located on the inner side of the filter element 2, and the raw water chamber 122 is formed between the outer side of the filter element 2 and the housing part 1. A water inlet channel is provided between the water inlet 111 and the raw water chamber 122 to connect the two, a backwash channel is provided between the clean water chamber 26 and the water inlet 111 to connect the two, and a plugging member 7 for opening and closing the sewage outlet 121 is provided at the sewage outlet 121. The utility model also includes a water channel switching mechanism, which is installed on the shell part and controls the water inlet channel and the backwash channel to switch on and off. Therefore, the backwash channel does not take in water when the utility model is in the filtering state, and does not take in water when the water inlet channel is in the backwash state.

[0036] In this embodiment, the housing part 1 specifically includes an inlet and outlet head 11 and a filter housing 12. The inlet and outlet head 11 is made of copper, but is not limited thereto. The inlet and outlet head 11 is provided with the water inlet 111 and the water outlet 112, and the water inlet 111 and the water outlet 112 are distributed left and right. The inlet and outlet head 11 is sealed and connected to the upper end of the filter housing 12. The lower end of the filter housing 12 is provided with a sewage outlet 121. Specifically, the lower end of the filter housing 12 is provided with a sewage outlet seat 13, and the sewage outlet seat 13 is provided with a sewage outlet 121. The filter element 2 is installed in the filter housing 12. The filter element 2 includes a laminated filter screen 21, which includes a plurality of laminated sheets 211 stacked and matched together, and a movable stop seat 22 is provided at one end of the laminated filter screen 21 close to the sewage outlet 121 (i.e., the lower end of the laminated filter screen 21), and the movable stop seat 22 is supported by an elastic member so that the plurality of laminated sheets 211 are in a mutually compressed state. Each laminated sheet is a disc structure with a texture structure on both sides, and solids in the water can be intercepted when water flows through the texture structure of the laminated sheet.

[0037] As a preferred embodiment, the water channel switching mechanism includes a water channel bracket 3 and a water channel switch 4. The water channel bracket 3 includes a first water flow portion 31 located on the water inlet channel and a second water flow portion 32 located on the backwash channel. The first water flow portion 31 is provided with a first water flow hole 311, and the second water flow portion 32 is provided with a second water flow hole 321. The water channel switch 4 cooperates with the water channel bracket 3, and the water channel switch 4 is driven to rotate by a driving member, so that the water channel switch 4 controls the first water flow hole 311 and the second water flow hole 321 to switch on by rotation.

[0038] In this embodiment, the water channel bracket 3 is coaxially arranged with the filter element, and the first water passing part 31 is annular and is provided with a plurality of first water passing holes 311 distributed along its circumferential direction; the second water passing part 32 is cylindrical and is provided with a plurality of second water passing holes 321 distributed along its circumferential direction; the first water passing part 31 is fixed at one end of the second water passing part 32 close to the purified water cavity 26. The water channel switch 4 includes a third water passing part 41 adapted to the first water passing part 31 and a fourth water passing part 42 adapted to the second water passing part 32. Therefore, the second water passing part 32 is also annular and the fourth water passing part 42 is cylindrical. The third water passing part 41 is provided with a plurality of third water passing holes 411 distributed along its circumferential direction, and the fourth water passing part 42 is provided with a plurality of fourth water passing holes 421 distributed along its circumferential direction. The water channel switch 4 rotates around the axis of the filter element to make the third water passing holes 411 correspond to or stagger from the first water passing holes 311 one by one, and make the fourth water passing holes 421 correspond to or stagger from the second water passing holes 321 one by one. When the third water passing holes 411 correspond to the first water passing holes 311 one by one, the fourth water passing holes 421 are staggered from the second water passing holes 321 one by one, so that the water inlet channel is opened and the backwashing channel is closed. When the third water passing holes 411 are staggered from the first water passing holes 311 one by one, the fourth water passing holes 421 correspond to the second water passing holes 321 one by one, so that the water inlet channel is closed and the backwashing channel is opened, thereby realizing the switching and opening of the water inlet channel and the backwashing channel.

[0039] In this embodiment, a backwashing filter screen 6 is arranged on the backwashing channel, and the backwashing filter screen 6 is located on the water inlet side of the second water passing part 32.

[0040] The utility model further includes a swirl member 23, which is connected to the water outlet side of the first water passing part 31. The third water passing part 41 is located between the first water passing part 31 and the swirl member 23, and the fourth water passing part 42 is located on the water outlet side of the second water inlet part. The swirl member 23 is provided with a plurality of swirl water channels 231 distributed along the same swirling direction. The swirl water channels 231 are inclined water channels or spiral water channels. One end of each swirl water channel 231 corresponds to a first water passing hole 311 one by one, and the other end of the swirl water channel 231 forms a water outlet hole 232 capable of laterally discharging water. Thus, when the water inlet channel is opened, each water outlet hole 232 laterally discharges water and forms a swirling water flow into the raw water cavity 122, so as to continuously wash the surface of the filter element 2 by rotation, and the water flow is always in a disturbed water flow state, making it not easy for dirt to adhere to the surface of the filter element 2. The swirl member 23 is located at the upper end of the laminated filter screen 21 and provides an upper limit for the top laminated sheet of the laminated filter screen 21, but is not limited thereto. In other embodiments, a fixing seat is arranged at the upper end of the laminated filter screen.

[0041] In this embodiment, the driving member is a valve stem 8, which is rotatably connected to the housing portion 1 around its axis and is relatively fixed to the waterway switch 4. Specifically, the inner ring of the waterway switch 4 is provided with a circle of first latch teeth 33, and the valve stem 8 is provided with a plurality of second latch teeth 82, and the first latch teeth 33 are meshed with the second latch teeth 82. One end of the valve stem 8 extends out of the housing portion 1, and the other end of the valve stem 8 passes through the clean water chamber 26 and is connected to the plugging member 7, so that the valve stem 8 drives the plugging member 7 to open or close the sewage outlet 121 by rotation. Specifically, one end of the valve stem 8 seals upward through the inlet and outlet water head 11, and a flushing knob 81 is provided. In other embodiments, the plugging member can be plugged in and out of the sewage outlet to control the opening or closing of the sewage outlet through plug-in and pull-out operations. In other embodiments, the driving member is electric, which includes a motor and a transmission assembly, and the motor is connected to the waterway switch through the transmission assembly, and the transmission assembly can be a gear transmission assembly, etc.

[0042] In this embodiment, the plugging member 7 can rotate with the valve stem 8 and can be axially moved relative to the valve stem 8 and is sleeved on the other end of the valve stem 8, and the plugging member 7 is provided with an external thread, which is threadedly connected with an internal thread of a fixed sleeve 9 fixed in the water purification chamber 26. In other embodiments, the plugging member 7 is relatively fixed to the valve stem 8, so that the valve stem 8 drives the plugging member 7 to rotate to open or close the sewage outlet 121. At this time, the plugging member 7 can adopt a mechanism similar to the third water-passing part of the waterway switch, that is, the plugging member 7 is eccentrically provided with a lower water outlet, and the sewage outlet 121 is opened or closed by corresponding to or staggered with the sewage outlet 121.

[0043] The filter element 2 of the present invention also includes a main filter screen 24, which is made of stainless steel, but is not limited thereto. It is located on the inner side of the laminated filter screen 21 to perform secondary filtration on the water passing through the laminated filter screen 21; the main filter screen 24 is mounted outside a filter element bracket 25. The filtering accuracy of the main filter screen 24 is higher than that of the laminated filter screen 21. Specifically, the filtering accuracy of the laminated filter screen 21 is 80-100 μm, and the filtering accuracy of the main filter screen 24 is 30-50 μm. Therefore, the laminated filter screen 21 is a coarse filter, and the main filter screen 24 is a fine filter. After the water flow is filtered by the laminated filter screen 21, it is further filtered by the main filter screen 24. The above-mentioned elastic member is specifically a spring 5, which is abutted and fitted between the movable seat 22 and the bottom of the filter element bracket 25.

[0044] In this embodiment, sealing rings or sealing gaskets are used to seal between various sealing parts. This is a conventional technology and will not be described in detail.

[0045] The utility model has two working states: a filtering state and a backwashing state. The two working states are respectively described below.

[0046] When the utility model is in the filtering state, the sewage outlet 121 is blocked by the blocking member 7. Each third water passing hole 411 of the water channel switch 4 corresponds to the corresponding first water passing hole 311 of the water channel bracket 3 respectively, and each fourth water passing hole 421 of the water channel switch 4 is staggered from the corresponding second water passing hole 321 of the water channel bracket 3, so that the water inlet channel is opened and the backwashing channel is in the closed state. At this time, the spring 5 is in the compressed state, and the adjacent laminations 211 of the laminated filter screen 21 are pressed against each other. When water enters from the water inlet 111, the water flow successively passes through each first water passing hole 311 and each third water passing hole 411 and flows to the swirl member 23, rotates through each swirl channel of the swirl member 23 and enters the raw water chamber 122, and successively passes through the laminated filter screen 21 and the main filter screen 24 and then enters the purified water chamber 26, and finally is output from the water outlet 112, as Figure 9 shown. The arrows in the figure indicate the water flow direction. During this process, since the backwashing channel is in the closed state, the backwashing filter screen 6 does not filter, but the water flow from the water inlet will scour the surface of the backwashing filter screen 6 downward, which is equivalent to flushing the backwashing filter screen 6, thereby reducing the dirt hanging on the surface of the backwashing filter screen 6.

[0047] When it is necessary to wash the filter element 2, rotate the washing knob 81 counterclockwise (the angle of each rotation of the washing knob 81 is 180°), so that the washing knob 81 drives the valve rod 8 to rotate, and the valve rod 8 drives the water channel switch 4 to rotate, so that each third water passing hole 411 of the water channel switch 4 is staggered from the corresponding first water passing hole 311 on the water channel bracket 3 respectively, and each fourth water passing hole 421 of the water channel switch 4 corresponds to the corresponding second water passing hole 321 of the water channel bracket 3, then the water inlet channel is closed and the backwashing channel is opened; when the valve rod 8 rotates, the valve rod 8 also drives the blocking member 7 to rotate, and at the same time the blocking member 7 moves upward to open the sewage outlet 121. When water enters from the water inlet 111, since the water inlet channel is closed, the water flow can only flow to the backwashing channel, and after being filtered by the backwashing filter screen 6, it flows into the purified water chamber 26, and then successively washes the main filter screen 24 and the laminated filter screen 21 and then is discharged from the sewage outlet 121, as Figure 10 shown. The arrows in the figure indicate the water flow direction. When the water flow is in the backwashing state and the sewage outlet 13 is opened, negative pressure is generated, and at the same time the water pressure acts downward on the movable seat 22, so that the movable seat 22 moves downward and compresses the spring 5. At this time, the laminations 211 of the laminated filter screen 21 are in the loose state and vibrate loosely under the action of the water flow, so that the intercepted objects sandwiched between the laminations 211 fall off and are immediately discharged, achieving the effect of flushing and discharging sewage.

[0048] After flushing the filter element 2, rotate the flushing knob 81 clockwise to reverse the rotation of the valve stem 8 by 180°, and drive the water channel switch 4 to return to the state where the water inlet channel is opened and the backwashing channel is closed. At the same time, the valve cover 8 drives the plugging member 7 to reset and close the sewage outlet 121. At this time, the pre-filter of the present invention returns to the filtering state again.

[0049] Therefore, for a pre-filter of the present invention, a water path switching mechanism is adopted to control the switching and opening of the water inlet channel and the backwashing channel, so that the backwashing channel is in a closed state during the filtering state, so that the backwashing filter screen 6 on the backwashing channel does not filter the water flow during the filtering state, and thus the fouling of the backwashing filter screen 6 can be reduced, ensuring that the backwashing filter screen 6 can filter normally during the backwashing state and meeting the requirements of backwashing. In particular, the backwashing filter screen 6 is located on the water inlet side of the second water passing part 32, so that the backwashing filter screen 6 not only does not filter the water flow during the filtering state, but also enables its surface to be flushed by the water flow, so that the backwashing filter screen 6 is flushed and the fouling of the backwashing filter screen 6 can be further reduced. In addition, the present invention adopts a double-layer filter screen for progressive filtration, which can not only greatly improve the filtration effect, but also effectively protect the main filter screen 24, thereby prolonging the service life of the filter.

[0050] For a pre-filter of the present invention, the parts not involved are the same as or can be implemented by the prior art.

[0051] The above embodiments are only used to further illustrate a pre-filter of the present invention, but the present invention is not limited to the embodiments. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A pre-filter, characterized in that: It includes a shell part and a filter element. The shell part is provided with a water inlet, a water outlet and a sewage outlet. The filter element is installed in the shell part and cooperates with the shell part to form a raw water chamber connected to the sewage outlet and a clean water chamber connected to the water outlet. A water inlet channel is provided between the water inlet and the raw water chamber to connect the two. A backwash channel is provided between the water inlet and the clean water chamber to connect the two. A plugging piece for opening and closing the sewage outlet is provided at the sewage outlet. It also includes a water channel switching mechanism, which is installed on the shell part and controls the switching and opening of the water inlet channel and the backwash channel.

2. The pre-filter according to claim 1, characterized in that: The water channel switching mechanism includes a water channel bracket and a water channel switch, the water channel bracket includes a first water flow portion located on the water inlet channel and a second water flow portion located on the backwash channel, the first water flow portion is provided with a first water flow hole, and the second water flow portion is provided with a second water flow hole; the water channel switch cooperates with the water channel bracket, and the water channel switch is driven to rotate by a driving member, so that the water channel switch controls the first water flow hole and the second water flow hole to switch on and off through rotation.

3. The pre-filter according to claim 2, characterized in that: The filter element is cylindrical, the water channel support is coaxially arranged with the filter element, the first water passing portion is annular and has a plurality of the first water passing holes distributed along its circumference; the second water passing portion is cylindrical and has a plurality of the second water passing holes distributed along its circumference.

4. The pre-filter according to claim 2 or 3, characterized in that: The water channel switch includes a third water flow portion adapted to the first water flow portion and a fourth water flow portion adapted to the second water flow portion, the third water flow portion is provided with a third water flow hole, and the fourth water flow portion is provided with a fourth water flow hole. The water channel switch is rotated around the axis of the filter element so that the third water flow hole corresponds to or is staggered with the first water flow hole one by one, and the fourth water flow hole corresponds to or is staggered with the second water flow hole one by one.

5. The pre-filter according to claim 2 or 3, characterized in that: A backwash filter is provided on the backwash channel and is located at the water inlet side of the second water passing portion.

6. The pre-filter according to claim 4, characterized in that: It also includes a swirl component, which is connected to the water outlet side of the first water pass portion, the third water pass portion is located between the first water pass portion and the swirl component, the swirl component is provided with a plurality of swirl water channels distributed along the same rotation direction, the swirl water channels are oblique water channels or spiral water channels, one end of the swirl water channel corresponds one-to-one with the first water pass hole, and the other end of the swirl water channel forms a water outlet hole that can discharge water laterally.

7. The pre-filter according to claim 2 or 3, characterized in that: The driving member is a valve stem, which is rotatably connected to the shell part around its axis and is relatively fixed to the water channel switch. One end of the valve stem extends out of the shell part and is provided with a flushing knob. The other end of the valve stem passes through the clean water chamber and is connected to the blocking member so that the valve stem drives the blocking member to open or close the sewage outlet by rotating.

8. The pre-filter according to claim 7, characterized in that: The plugging piece can rotate with the valve stem and can be axially moved relative to the valve stem so as to be sleeved on the other end of the valve stem. The plugging piece is provided with an external thread which is threadedly connected with an internal thread provided on a fixed sleeve fixed in the water purification chamber.

9. The pre-filter according to claim 1, characterized in that: The filter element includes a laminated filter screen, which includes a plurality of laminated sheets that are stacked and matched together, and a movable limit seat is provided at one end of the laminated filter screen close to the sewage outlet, and the movable limit seat is supported by an elastic member so that the plurality of laminated sheets are in a state of being pressed against each other.

10. The pre-filter according to claim 9, wherein: The filter element further comprises a main filter screen, which is located at the inner side of the laminated filter screen, and the filtering accuracy of the main filter screen is higher than the filtering accuracy of the laminated filter screen, and the main filter screen is sleeved outside a filter element bracket.

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