Water tank type low-pressure reverse osmosis water purifier

Abstract

The utility model provides a water tank type low pressure reverse osmosis water purifier which comprises a base, a machine barrel, a water storage tank and a water outlet faucet, the machine barrel, the water storage tank and the water outlet faucet are fixed on the base, a filter element assembly is detachably installed in the machine barrel, the water storage tank is communicated with the machine barrel, and pure water filtered by the filter element assembly is stored in the water storage tank; a water suction pump is installed in the base, the water storage tank, the water suction pump and the water outlet faucet are sequentially communicated, a control switch is arranged on the water outlet faucet, and the control switch is electrically connected with the water suction pump and used for controlling opening and closing of the water suction pump; when the water purifier is used, the control switch is turned on, the water suction pump is started to pump out pure water stored in the water storage tank, and the pure water flows out of the water outlet faucet; the water tank type low-pressure reverse osmosis water purifier provided by the utility model overcomes the defect that the water yield of the existing low-pressure reverse osmosis water purifier is small.

Description

Technical Field

[0001] This utility model relates to the field of low-pressure reverse osmosis water purifiers, and in particular to a water tank type low-pressure reverse osmosis water purifier. Background Technology

[0002] With water resources receiving increasing attention, water purifiers have become essential devices for ensuring the safety of household and industrial water use. Reverse osmosis water purifiers are particularly popular due to their ability to effectively remove impurities, bacteria, viruses, heavy metals, and other pollutants from water. However, traditional reverse osmosis water purifiers typically require electricity, which presents limitations in areas with unstable or unavailable power supplies, as well as in scenarios where energy conservation and environmental protection are prioritized.

[0003] To overcome the aforementioned problems, low-pressure (electricity-free) reverse osmosis water purifiers have emerged, aiming to achieve efficient water purification without excessive reliance on external power sources, providing users with a wider range of, more reliable, and more energy-efficient water purification solutions. While existing low-pressure reverse osmosis water purifiers can adapt to low-pressure environments, in actual use, their slow real-time filtration speed results in a small amount of pure water produced, and the low outlet pressure and small water flow from the faucet make water use inconvenient and impractical. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] The problem to be solved by this utility model is to provide a water tank type low-pressure reverse osmosis water purifier to overcome the defect of small water output of existing low-pressure reverse osmosis water purifiers.

[0006] (II) Technical Solution

[0007] To solve the aforementioned technical problem, this utility model provides a water tank type low-pressure reverse osmosis water purifier, including a base, a barrel fixed on the base, a water storage tank, and a water outlet. A filter element assembly is detachably installed inside the barrel. The water storage tank is connected to the barrel, and the purified water filtered by the filter element assembly is stored in the water storage tank. A water pump is installed inside the base. The water storage tank, the water pump, and the water outlet are connected in sequence. A control switch is provided on the water outlet, and the control switch is electrically connected to the water pump to control its opening and closing. In use, when the control switch is turned on, the water pump starts to draw out the purified water stored in the water storage tank and it flows out from the water outlet.

[0008] In some embodiments, the bottom of the barrel is provided with a pure water pipe, a raw water pipe and a wastewater pipe extending downwards, and a four-way valve is installed in the base. The pure water pipe and the raw water pipe are respectively connected to the four-way valve. The top of the water storage tank is provided with a water tank inlet and the bottom of the tank is provided with a water tank outlet. The water tank inlet is connected to the four-way valve and the water tank outlet is connected to the water pump.

[0009] In some embodiments, the water tank includes a water tank body fixed to the base and a water tank cover fixed to the top of the water tank body. The water tank inlet is disposed on the water tank cover, and a mechanical float level switch is installed at the water tank inlet. The bottom of the water tank body is recessed to form a water collection trough, and the water tank outlet is disposed in the water collection trough.

[0010] In some embodiments, the faucet includes a mounting base, a straight pipe fixed on the mounting base, and a control switch mounted on the mounting base, the straight pipe being connected to the water pump; the water tank type low-pressure reverse osmosis water purifier also includes a top cover located at the top, the top cover covering the barrel and the water storage tank.

[0011] In some embodiments, an annular protrusion is provided inside the lower end of the barrel, the pure water pipe is provided at the center of the annular protrusion, the wastewater pipe is connected inside the annular protrusion, and the raw water pipe is connected outside the annular protrusion.

[0012] In some embodiments, the filter element assembly includes a cylindrical double-layer composite filter element, an upper end cap and a lower end cap respectively fixed to the upper and lower ends of the double-layer composite filter element, and a reverse osmosis membrane filter element detachably installed inside the double-layer composite filter element. The lower end cap is inserted into the annular protrusion. An installation cavity is formed inside the double-layer composite filter element, and the reverse osmosis membrane filter element is concentrically arranged in the installation cavity. An insertion port is provided on the upper end cap, through which the reverse osmosis membrane filter element can be inserted from top to bottom into the installation cavity. A filter element cover for covering the insertion port is detachably installed on the upper end cap. A positioning post is provided on the filter element cover extending toward the reverse osmosis membrane filter element, and a positioning groove matching the positioning post is provided on the reverse osmosis membrane filter element.

[0013] In some embodiments, the filter element cover is detachably connected to the upper end cover by a rotating snap-fit ​​mechanism. The outer circumferential wall of the upper end cover is provided with a plurality of rotating buckles at equal intervals in a ring. The filter element cover is provided with a plurality of rotating slots that can engage with the rotating buckles. One end of the rotating buckle is provided with an arc-shaped anti-detachment protrusion. One side of the rotating slot is provided with an anti-detachment groove that matches the anti-detachment protrusion. One side of the anti-detachment groove is provided with a stop block. The side of the stop block facing away from the anti-detachment groove is provided with an inclined guide wall.

[0014] In some embodiments, the upper end of the filter cartridge cover is provided with a petal-shaped screw-on part; a first sealing ring is fitted on the upper end cover, and the first sealing ring can be pressed tightly after the filter cartridge cover is tightened; the double-layer composite filter cartridge includes an outer PP cotton filter layer and an inner activated carbon filter layer, and the activated carbon filter layer is fixed inside the PP cotton filter layer; the reverse osmosis membrane filter cartridge includes a product water pipe located in the center, the positioning groove is provided on the upper part of the product water pipe, and the product water pipe is connected to the pure water pipe.

[0015] In some embodiments, the lower end cap extends upward and is provided with a limiting post, and the double-layer composite filter element is located outside the limiting post; the bottom of the reverse osmosis membrane filter element has a conical pad, and the conical pad is located inside the limiting post; a plurality of limiting plates are provided at equal intervals in an annular shape on the lower side of the lower end cap, and the limiting plates are used to limit the reverse osmosis membrane filter element to prevent it from falling out of the double-layer composite filter element.

[0016] In some embodiments, a cylinder cover is threadedly connected to the top of the barrel, and an external thread is provided at the opening at the upper end of the barrel, with the cylinder cover threadedly connected to the external thread; a pressure post is provided at the center of the cylinder cover, and the pressure post is used to press down the filter element assembly; a second sealing ring is installed between the cylinder cover and the barrel.

[0017] (III) Beneficial Effects

[0018] The water tank type low-pressure reverse osmosis water purifier provided by this utility model has the following advantages compared with the prior art:

[0019] 1) A water storage tank, a water pump, and a control switch are added. The pure water filtered by the filter element is stored in the water storage tank. When water is needed, the control switch is turned on, the water pump starts to draw out the pure water stored in the water storage tank and it flows out from the faucet. Since the water storage tank can store a large amount of pure water, and with the water pump pressurization, and since there is no switch valve in the straight pipe of the faucet, the water flow of the faucet is large, making it very convenient to use water.

[0020] 2) The filter element is a split type. The reverse osmosis membrane filter element can be detachably installed inside the double-layer composite filter element. In actual use, the double-layer composite filter element or the reverse osmosis membrane filter element can be selectively replaced according to the degree of dirt or service life. The filter element components can be flexibly replaced without the need for complete scrapping, making it more environmentally friendly. The filter element cover is connected to the upper cover by a snap-fit ​​method. When disassembling, simply rotate the filter element cover, which is convenient for disassembly and assembly. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a perspective view of a water tank type low-pressure reverse osmosis water purifier in use according to this utility model;

[0023] Figure 2 This is a three-dimensional view of the interior of the base of a water tank type low-pressure reverse osmosis water purifier according to the present invention;

[0024] Figure 3 This is an exploded view of a water tank type low-pressure reverse osmosis water purifier according to this utility model;

[0025] Figure 4 This is a cross-sectional view of a water tank type low-pressure reverse osmosis water purifier according to the present invention;

[0026] Figure 5 This is a perspective view of the water tank of a water tank type low-pressure reverse osmosis water purifier according to the present invention;

[0027] Figure 6 This is a perspective view of the water outlet faucet of a water tank type low-pressure reverse osmosis water purifier according to this utility model;

[0028] Figure 7 This is a perspective view of the bottom of the barrel of a water tank type low-pressure reverse osmosis water purifier according to this utility model;

[0029] Figure 8 This is a schematic diagram of the structure of the barrel of a water tank type low-pressure reverse osmosis water purifier according to the present invention;

[0030] Figure 9 for Figure 8 A sectional view taken along section AA;

[0031] Figure 10 This is a perspective view of a water tank type low-pressure reverse osmosis water purifier filter element assembly according to the present invention;

[0032] Figure 11 This is an exploded view of a water tank type low-pressure reverse osmosis water purifier filter element assembly according to the present invention;

[0033] Figure 12 This is a cross-sectional view of a water tank type low-pressure reverse osmosis water purifier filter element assembly according to the present invention;

[0034] Figure 13 This is a perspective view of a water tank type low-pressure reverse osmosis water purifier filter cartridge cover according to the present invention;

[0035] Figure 14 This is a perspective view of the upper cover of a water tank type low-pressure reverse osmosis water purifier according to the present invention.

[0036] The component names corresponding to the various labels in the diagram are as follows: 1. Base; 2. Machine barrel; 201. Pure water pipe; 202. Raw water pipe; 203. Wastewater pipe; 204. Annular boss; 205. External thread; 3. Water storage tank; 31. Water tank body; 32. Water tank cover; 301. Water tank inlet; 302. Water tank outlet; 303. Water collection trough; 4. Water tap; 41. Control switch; 42. Mounting base; 43. Straight pipe; 5. Filter element assembly; 51. Double-layer composite filter element; 52. Upper end cover; 53. Lower end cover; 54. Reverse osmosis membrane filter element; 55. Filter... 56. Core cover; 511. First sealing ring; 512. Installation cavity; 513. PP cotton filter layer; 524. Activated carbon filter layer; 525. Insertion port; 526. Rotary buckle; 527. Anti-detachment protrusion; 538. Limiting post; 539. Limiting plate; 540. Positioning groove; 541. Water production pipe; 552. Rotary slot; 553. Anti-detachment groove; 554. Stop block; 555. Inclined guide wall; 556. Tightening part; 6. Water pump; 7. Four-way valve; 8. Top cover; 9. Cylinder cover; 901. Pressure post; 10. Second sealing ring. Detailed Implementation

[0037] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0038] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0040] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0041] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0042] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0043] See Figures 1 to 14 This utility model provides a water tank type low-pressure reverse osmosis water purifier, including a base 1, a barrel 2 fixed on the base 1, a water storage tank 3, and a water outlet 4. The barrel 2 is located on one side of the water storage tank 3, and a filter element assembly 5 is detachably installed inside the barrel 2. The filter element assembly 5 is replaceable. The water storage tank 3 is connected to the barrel 2, and the pure water filtered by the filter element assembly 5 is stored in the water storage tank 3. A water pump 6 is installed inside the base 1. The water storage tank 3, the water pump 6, and the water outlet 4 are connected in sequence through pipelines. A control switch 41 is provided on the water outlet 4, and the control switch 41 is electrically connected to the water pump 6 to control the opening and closing of the water pump 6. In use, the control switch 41 is turned on, the water pump 6 starts to draw out the pure water stored in the water storage tank 3, and the water flows out from the water outlet 4.

[0044] This structure adds a water storage tank, a water pump, and a control switch. The pure water filtered by the filter element is stored in the water storage tank. When water is needed, the control switch is turned on, and the water pump starts to draw out the pure water stored in the water storage tank and let it flow out from the faucet. Since the water storage tank can store a large amount of pure water, and with the water pump pressurizing it, and since there are no switch valves in the straight pipe of the faucet, the water flow of the faucet is large, ensuring the water flow rate and making it very convenient to use water.

[0045] In some embodiments, such as Figure 2 , Figure 4 and Figure 5 As shown, the bottom of the barrel 2 extends downwards and is equipped with a pure water pipe 201, a raw water pipe 202, and a wastewater pipe 203. The raw water pipe 202 is used for raw water (tap water) to enter the barrel 2, the pure water pipe 201 is used for the discharge of filtered pure water, and the wastewater pipe 203 is used for the discharge of generated wastewater. A four-way valve 7 is installed inside the base 1. The pure water pipe 201 and the raw water pipe 202 are respectively connected to the four-way valve 7 through pipes. The top of the water storage tank 3 is equipped with a water tank inlet 301, and the bottom of the water storage tank 3 is equipped with a water tank outlet 302. The water tank inlet 301 is connected to the four-way valve 7 through a pipe, and the water tank outlet 302 is connected to the water pump 6 through a pipe. The four-way valve is existing technology and will not be described in detail in this embodiment. When in use, the pure water filtered by the filter element assembly 5 passes through the pure water pipe 201, the four-way valve 7 and the water tank inlet 301 and is stored in the water storage tank 3; when the control switch 41 is turned on, the water pump 6 starts, and the pure water in the water storage tank 3 flows out through the water tank outlet 302, the water pump 6 and the water tap 4.

[0046] In some embodiments, such as Figures 3 to 5 As shown, the water storage tank 3 includes a tank body 31 fixed to the base 1 and a tank cover 32 fixed to the top of the tank body 31. A water tank inlet 301 is located on the tank cover 32, and a mechanical float level switch (not shown in the figure) is installed at the water tank inlet 301. The mechanical float level switch is existing technology and will not be described further in this embodiment. With the mechanical float level switch, when the water level in the storage tank 3 reaches a set height, the mechanical float level switch will close the water tank inlet 301, achieving automatic control of the water level and improving performance. A water accumulation trough 303 is formed by a recess at the bottom of the tank body 31, and the water tank outlet 302 is located within the water accumulation trough 303. The water accumulation trough 303 allows water to accumulate in the storage tank 3 when the amount of pure water in the storage tank 3 is low, thus ensuring that the water in the storage tank 3 is completely used up.

[0047] In some embodiments, such as Figure 1 and Figure 6 As shown, the water faucet 4 includes a mounting base 42, a straight pipe 43 fixed on the mounting base 42, and a control switch 41 mounted on the mounting base 42. The straight pipe 43 is connected to the water pump 6. Since this product uses the control switch 41 to turn the water pump 6 on and off to control the water output, there is no need to install valve cores or other components such as a switch valve in the straight pipe 43 of this water faucet 4, resulting in a larger outlet diameter and ensuring a larger water output. The tank-type low-pressure reverse osmosis water purifier also includes a top cover 8, which covers the casing 2 and the water storage tank 3.

[0048] In some embodiments, such as Figure 4 as well as Figures 7 to 9As shown, an annular boss 204 is provided inside the lower end of the barrel 2. A pure water pipe 201 is provided at the center of the annular boss 204. A wastewater pipe 203 is connected inside the annular boss 204, and a raw water pipe 202 is connected outside the annular boss 204.

[0049] In some embodiments, such as Figure 4 as well as Figures 10 to 12 As shown, the filter element assembly 5 includes a cylindrical double-layer composite filter element 51, an upper end cap 52 and a lower end cap 53 fixed to the upper and lower ends of the double-layer composite filter element 51 respectively, and a reverse osmosis membrane filter element 54 detachably installed in the double-layer composite filter element 51. The lower end cap 53 is inserted into the annular protrusion 204. An installation cavity 511 is formed in the double-layer composite filter element 51, and the reverse osmosis membrane filter element 54 is concentrically arranged in the installation cavity 511. An insertion port 521 is provided on the upper end cap 52, and the reverse osmosis membrane filter element 54 can be inserted into the installation cavity 511 from top to bottom through the insertion port 521. A filter element cover 55 for covering the insertion port 521 is detachably installed on the upper end cap 52. A positioning post 551 is provided on the filter element cover 55 extending toward the reverse osmosis membrane filter element 54, and a positioning groove 541 matching the positioning post 551 is provided on the reverse osmosis membrane filter element 54.

[0050] Existing composite filter cartridges are generally one-piece structures, meaning three filter cartridges are combined into a single unit, requiring replacement of the entire cartridge. However, the outermost filter cartridge is most prone to contamination. Even if the outermost cartridge is dirty and has reached the end of its lifespan, the innermost reverse osmosis membrane cartridge may still be clean and not yet at the end of its lifespan. Replacing the entire cartridge can be wasteful and is not environmentally friendly. This new structure uses a split-type filter cartridge assembly. The reverse osmosis membrane cartridge can be detachably installed inside the double-layer composite filter cartridge. In actual use, the double-layer composite filter cartridge or the reverse osmosis membrane cartridge can be selectively replaced based on the level of contamination or the cartridge's lifespan. This flexible replacement of filter cartridge components eliminates the need for complete replacement, making it more environmentally friendly.

[0051] In some embodiments, such as Figures 10 to 14 As shown, the filter element cover 55 is detachably connected to the upper end cover 52 by a rotating snap-fit. The outer circumferential wall of the upper end cover 52 is provided with a plurality of rotating buckles 522 at equal intervals. The filter element cover 55 is provided with a plurality of rotating slots 552 that can engage with the rotating buckles 522. One end of the rotating buckle 522 is provided with an arc-shaped anti-detachment protrusion 523. One side of the rotating slot 552 is provided with an anti-detachment groove 553 that matches the anti-detachment protrusion 523. One side of the anti-detachment groove 553 is provided with a stop 554 protruding. The side of the stop 554 facing away from the anti-detachment groove 553 is provided with an inclined guide wall 555.

[0052] In this structure, during filter cover installation, as the rotating buckle engages with the rotating groove, the anti-detachment protrusion, guided by the inclined guide wall, can overcome the stop and enter the anti-detachment groove. The stop provides some resistance to the anti-detachment protrusion, preventing the filter cover from loosening during use and ensuring reliability. When removing the filter cover, if the force applied to rotating the cover exceeds the resistance of the stop, the anti-detachment protrusion can overcome the stop, allowing the rotating buckle to smoothly disengage from the rotating groove.

[0053] In some embodiments, such as Figures 10 to 14 As shown, the upper end of the filter element cover 55 is provided with a petal-shaped screw part 556; the screw part is easy for people to hold and easy to rotate. A first sealing ring 56 is fitted on the upper cover 52, and the first sealing ring 56 can be pressed tightly after the filter element cover 55 is tightened; the first sealing ring can ensure the airtightness of the connection between the filter element cover and the upper cover.

[0054] The dual-layer composite filter element 51 includes an outer PP cotton filter layer 512 and an inner activated carbon filter layer 513, with the activated carbon filter layer 513 fixed inside the PP cotton filter layer 512. The reverse osmosis membrane filter element 54 includes a central product water pipe 542, with a positioning groove 541 positioned above the product water pipe 542, which is connected to the pure water pipe 201. During filtration, raw water (tap water) enters the filter cylinder through the raw water pipe, then passes through the PP cotton filter layer, the activated carbon filter layer, and the reverse osmosis membrane filter element in sequence for filtration. Finally, the water flows out through the product water pipe from the pure water pipe, while the wastewater generated by the reverse osmosis membrane filter element flows out through the wastewater pipe.

[0055] In some embodiments, such as Figures 10 to 14 As shown, the lower end cover 53 extends upward and is provided with a limiting post 531, and the double-layer composite filter element 51 is located outside the limiting post 531; the bottom of the reverse osmosis membrane filter element 54 has a conical pad (not shown in the figure), and the conical pad is located inside the limiting post 531; multiple limiting plates 532 are provided at equal intervals in an annular shape on the lower side of the lower end cover 53, and the limiting plates 532 are used to limit the reverse osmosis membrane filter element 54 to prevent it from falling out of the double-layer composite filter element 51.

[0056] In some embodiments, such as Figure 4 and Figure 7 As shown, a cover 9 is threadedly connected to the top of the barrel 2, and an external thread 205 is provided at the opening at the upper end of the barrel 2. The cover 9 is threadedly connected to the external thread 205. A pressure post 901 is provided at the center of the cover 9, which is used to press down the filter element assembly 5. A second sealing ring 10 is installed between the cover 9 and the barrel 2.

[0057] The same or similar parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments.

[0058] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A tank-type low-pressure reverse osmosis water purifier, characterized in that: The device includes a base (1), a barrel (2) fixed on the base (1), a water tank (3), and a water tap (4). A filter element assembly (5) is detachably installed inside the barrel (2). The water tank (3) is connected to the barrel (2), and the pure water filtered by the filter element assembly (5) is stored in the water tank (3). A water pump (6) is installed inside the base (1). The water tank (3), the water pump (6), and the water tap (4) are connected in sequence. A control switch (41) is provided on the water tap (4). The control switch (41) is electrically connected to the water pump (6) to control its opening and closing. When in use, the control switch (41) is turned on, and the water pump (6) starts to draw out the pure water stored in the water tank (3) and flow out from the water tap (4).

2. The tank-type low-pressure reverse osmosis water purifier as described in claim 1, characterized in that: The bottom of the barrel (2) extends downward and is provided with a pure water pipe (201), a raw water pipe (202) and a wastewater pipe (203). A four-way valve (7) is installed in the base (1). The pure water pipe (201) and the raw water pipe (202) are respectively connected to the four-way valve (7). The top of the water storage tank (3) is provided with a water tank inlet (301) and the bottom is provided with a water tank outlet (302). The water tank inlet (301) is connected to the four-way valve (7) and the water tank outlet (302) is connected to the water pump (6).

3. The water tank type low-pressure reverse osmosis water purifier as described in claim 2, characterized in that: The water storage tank (3) includes a water tank body (31) fixed on the base (1) and a water tank cover (32) fixed on the top of the water tank body (31). The water tank inlet (301) is located on the water tank cover (32), and a mechanical float level switch is installed at the water tank inlet (301). The bottom of the water tank body (31) is recessed to form a water accumulation trough (303), and the water tank outlet (302) is located in the water accumulation trough (303).

4. The tank-type low-pressure reverse osmosis water purifier as described in claim 1, characterized in that: The water tap (4) includes a mounting base (42), a straight pipe (43) fixed on the mounting base (42), and a control switch (41) installed on the mounting base (42). The straight pipe (43) is connected to the water pump (6). The water tank type low-pressure reverse osmosis water purifier also includes a top cover (8) located at the top, which covers the barrel (2) and the water storage tank (3).

5. The water tank type low-pressure reverse osmosis water purifier as described in claim 2, characterized in that: The lower end of the barrel (2) is provided with an annular boss (204), the pure water pipe (201) is provided at the center of the annular boss (204), the wastewater pipe (203) is connected to the inside of the annular boss (204), and the raw water pipe (202) is connected to the outside of the annular boss (204).

6. The tank-type low-pressure reverse osmosis water purifier as described in claim 5, characterized in that: The filter element assembly (5) includes a cylindrical double-layer composite filter element (51), an upper end cap (52) and a lower end cap (53) fixed at the upper and lower ends of the double-layer composite filter element (51) respectively, and a reverse osmosis membrane filter element (54) detachably installed inside the double-layer composite filter element (51). The lower end cap (53) is inserted into the annular protrusion (204). An installation cavity (511) is formed inside the double-layer composite filter element (51), and the reverse osmosis membrane filter elements (54) are concentrically arranged in the installation cavity (511). The upper end cover (52) is provided with an insertion port (521), through which the reverse osmosis membrane filter element (54) can be inserted from top to bottom into the mounting cavity (511); the upper end cover (52) is detachably installed with a filter element cover (55) for covering the insertion port (521), the filter element cover (55) extends toward the reverse osmosis membrane filter element (54) and is provided with a positioning post (551), and the reverse osmosis membrane filter element (54) is provided with a positioning groove (541) that matches the positioning post (551).

7. The tank-type low-pressure reverse osmosis water purifier as described in claim 6, characterized in that: The filter element cover (55) is detachably connected to the upper end cover (52) by a rotating snap-fit. The outer circumferential wall of the upper end cover (52) is provided with a plurality of rotating buckles (522) at equal intervals. The filter element cover (55) is provided with a plurality of rotating slots (552) that can engage with the rotating buckles (522). One end of the rotating buckle (522) is provided with an arc-shaped anti-detachment protrusion (523). One side of the rotating slot (552) is provided with an anti-detachment groove (553) that is adapted to the anti-detachment protrusion (523). One side of the anti-detachment groove (553) is provided with a stop (554) protruding out. The side of the stop (554) away from the anti-detachment groove (553) is provided with an inclined guide wall (555).

8. The water tank type low-pressure reverse osmosis water purifier as described in claim 6, characterized in that: The upper end of the filter element cover (55) is provided with a petal-shaped screw part (556); a first sealing ring (56) is fitted on the upper end cover (52), and the first sealing ring (56) can be pressed tightly after the filter element cover (55) is tightened. The dual-layer composite filter element (51) includes an outer PP cotton filter layer (512) and an inner activated carbon filter layer (513), the activated carbon filter layer (513) being fixed inside the PP cotton filter layer (512); the reverse osmosis membrane filter element (54) includes a central product water pipe (542), the positioning groove (541) being disposed on the upper part of the product water pipe (542), and the product water pipe (542) being connected to the pure water pipe (201).

9. The tank-type low-pressure reverse osmosis water purifier as described in claim 6, characterized in that: The lower end cap (53) extends upward and is provided with a limiting post (531), and the double-layer composite filter element (51) is located outside the limiting post (531); the bottom of the reverse osmosis membrane filter element (54) has a conical pad, and the conical pad is located inside the limiting post (531); a plurality of limiting plates (532) are provided at equal intervals in an annular shape on the lower side of the lower end cap (53), and the limiting plates (532) are used to limit the reverse osmosis membrane filter element (54) to prevent it from falling out of the double-layer composite filter element (51).

10. The tank-type low-pressure reverse osmosis water purifier as described in claim 1, characterized in that: The top of the barrel (2) is threaded with a cover (9), and the opening at the upper end of the barrel (2) is provided with an external thread (205). The cover (9) is threaded onto the external thread (205). A pressure post (901) is provided at the center of the cover (9), and the pressure post (901) is used to press down the filter element assembly (5). A second sealing ring (10) is installed between the cover (9) and the barrel (2).

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