A backflush prefilter

Abstract

The application discloses a back-flushing pre-filter, which comprises a filter core assembly, a water distributor, a flow channel switching part, a power assembly and a filter body with a fluid inlet, a fluid outlet and a blowdown port, and the inner and outer sides of the filter core assembly form a clean water cavity and a raw water cavity respectively; the water distributor divides the raw water cavity into upper and lower cavities; in the filtering state, the flow channel switching part moves upward, the upper and lower cavities are communicated with each other; fluid flows into the upper and lower cavities from the fluid inlet, then enters the clean water cavity from the upper and lower cavities, and finally flows out from the fluid outlet through the clean water cavity; in the back-flushing state, the flow channel switching part moves downward, the upper and lower cavities are separated from each other; fluid enters the upper cavity from the fluid inlet, then flows into the clean water cavity from the upper cavity, then enters the lower cavity from the clean water cavity, and finally is discharged from the blowdown port through the lower cavity. The filter is filtered when the flow channel switching part rises, and back-flushed when the flow channel switching part falls; the movement mode is completely opposite to that of the prior art, and a brand-new design idea is provided.

Description

Technical Field

[0001] This invention relates to a pre-filter, and more particularly to a backwashing pre-filter. Background Technology

[0002] In existing technologies, pre-filters primarily achieve backwashing by raising and lowering the filter element assembly to switch the flow path. Of course, some pre-filters also use a scraper sleeve to switch the flow path. Currently, products on the market that use a scraper sleeve to change the flow path operate as follows: the scraper sleeve rises to enter backwashing mode; the scraper sleeve descends to enter normal filtration mode.

[0003] For example, patent CN210229284U discloses a backwashing pre-filter, including a valve body with an inlet, an outlet, and a lower port. A filter bottle is connected to the lower port of the valve body, and a filter element assembly is installed inside the filter bottle. A transmission knob is fitted below the filter bottle, and a drain valve is located below the transmission knob. The filter element assembly includes a filter element assembly, a backwashing brush sleeve, a lifting screw, and a transmission component. The lifting screw is threaded to the bottom of the filter element assembly. The filter element assembly has several water inlet and distribution holes, and a sealing element for sealing the water inlet and distribution holes is provided between the filter element assembly and the backwashing brush sleeve.

[0004] In patent CN210229284U, when the backwashing brush sleeve (scraper sleeve) rises, the water inlet distribution hole is blocked, and the backwashing operation is performed at this time; when the backwashing scraper sleeve descends, the water inlet distribution hole is opened, and normal filtration is performed at this time.

[0005] Based on this, the present invention provides a backwashing pre-filter with completely opposite movement modes, namely, normal filtration is performed when the scraper sleeve rises and backwashing is performed when the scraper sleeve falls.

[0006] In addition, patent CN210229284U requires two steps to be completed when performing backwashing.

[0007] First, the user needs to turn the transmission knob, which drives the "screw structure" to move the backwash brush sleeve upward and block the water inlet distribution hole, thereby changing the water flow path.

[0008] Then, open the ball valve;

[0009] Finally, the filter element assembly is backwashed, and the wastewater is discharged from the opened ball valve.

[0010] This two-step backwashing operation, while relatively simple, does not meet consumers' "foolproof" usage needs—"one-button backwashing." Summary of the Invention

[0011] This invention provides a backwashing pre-filter with a novel design concept. Its purpose is to provide a backwashing pre-filter with completely opposite movement modes, namely, normal filtration is performed when the flow channel switching section rises, and backwashing is performed when the flow channel switching section falls.

[0012] To achieve the objective, the technical solution provided by this invention is as follows:

[0013] A backwashing pre-filter includes a filter element assembly, a water distributor with water distribution holes, and a filter body having a fluid inlet, a fluid outlet, and a drain outlet. The filter element assembly is installed inside the filter body, with a raw water chamber formed on the outer side of the filter element assembly and a clean water chamber formed on the inner side of the filter element assembly. The water distributor is installed between the filter element assembly and the filter body, and divides the raw water chamber into an upper chamber and a lower chamber. The backwashing pre-filter further includes a flow channel switching part installed inside the filter body and a power component for moving the flow channel switching part.

[0014] Filtration state: The flow channel switching part moves upward relative to the water distributor, so that the upper and lower chambers are connected to each other; the fluid flows into the upper and lower chambers from the fluid inlet, then enters the clean water chamber from the upper and lower chambers, and finally flows out from the fluid outlet through the clean water chamber;

[0015] Backwashing state: The flow channel switching part moves downward relative to the water distributor, so that the upper and lower chambers are separated from each other; the fluid enters the upper chamber from the fluid inlet, then flows into the clean water chamber from the upper chamber, then enters the lower chamber from the clean water chamber, and finally exits from the drain outlet through the lower chamber.

[0016] In the recommended embodiment, the power assembly includes a reset assembly with restoring force and a lower partition, which divides the lower cavity into an upper water pressure chamber and a lower drain chamber, the drain chamber being connected to a drain outlet; and the drain outlet is often connected to a ball valve, which controls the opening or closing state of the drain outlet.

[0017] When the drain outlet (ball valve) is closed, the reset assembly simultaneously pushes up the flow channel switching section and the lower partition section, separating the water pressure chamber and the drain chamber, while the upper and lower chambers are connected to each other. At this time, water flows from the fluid inlet into the upper chamber and the lower chamber in sequence, and then enters the clean water chamber from the upper and lower chambers respectively, and finally flows out from the fluid outlet through the clean water chamber; thus, the filtration process is completed.

[0018] When the drain outlet is opened, the pressure difference between the water pressure chamber and the drain chamber is greater than the restoring force of the reset component. The pressure difference presses down the lower partition and connects the water pressure chamber and the drain chamber. At the same time, the lower partition drives the flow channel switching part to move down, separating the upper and lower chambers. At this time, the water flows into the upper chamber from the fluid inlet, then flows into the clean water chamber from the upper chamber, then into the lower chamber from the clean water chamber, and finally exits from the drain outlet through the lower chamber, thus completing the backwashing process.

[0019] This implementation fully utilizes the pressure difference between the upper and lower parts of the lower partition. During use, simply controlling the opening / closing of the drain port, typically just the opening / closing of the ball valve, is sufficient to switch between filtration and backwashing modes, achieving a "one-button backwashing" effect.

[0020] In the recommended embodiment, the power assembly further includes a cylindrical scraper sleeve, the upper end of which is rotatably connected to the flow channel switching part, and the lower end of which is fixedly connected to the lower partition part. The scraper sleeve moves up and down with the lower partition part, and simultaneously, under the action of an external force, it can rotate relative to the flow channel switching part. During operation, the scraper sleeve typically moves up and down first, and then rotates as needed once it reaches the designated position. These two actions are usually performed independently and do not interfere with each other.

[0021] In the recommended embodiment, the filter body includes a valve head and a filter bottle connected to each other. The scraper sleeve includes a cylindrical scraper frame and a scraper part capable of simultaneously scraping the filter bottle and filter element assembly. The scraper part is fixedly installed on the scraper frame. The scraper part is usually provided with protrusions for scraping and cleaning. The shape of the protrusions is not limited; they can be sheet-like or toothed, depending on the specific needs. This embodiment adopts a "double-sided scraper" structure. When the scraper sleeve rotates, it can clean the filter bottle and filter element assembly simultaneously, achieving an ideal cleaning effect.

[0022] Although the "double-sided scraper" increases the friction of the scraper sleeve's up-and-down movement compared to the "single-sided scraper (scraping only the filter element or only the filter bottle)," and inevitably leads to higher water pressure requirements, the all-plastic scraper sleeve is lightweight. Therefore, even in situations with low water pressure (0.5 kg to 1 kg), it is still possible to switch between filtration and backwashing states by opening / closing the drain outlet, thus achieving the goal of "one-button backwashing."

[0023] In the recommended embodiment, the flow channel switching part includes a sealing ring and a lower hook part connected to each other. The sealing ring is located directly above the water distributor and can seal the water distribution hole. The lower hook part passes through the water distribution hole of the corresponding water distributor from top to bottom. The upper end of the scraper sleeve is provided with an upper annular groove, the lower hook part is engaged in the upper annular groove, and the scraper sleeve can rotate relative to the lower hook part.

[0024] In the recommended embodiment, the bottom surface of the lower partition is provided with a blind insertion hole; the backwash pre-filter also includes a rotatable fork, which includes an inner pipe sleeve and a rod fixedly connected to each other. The inner pipe sleeve is sealed and installed inside the drain port, and the rod is inserted into the corresponding blind insertion hole. In this embodiment, the scraper sleeve moves up and down with the lower partition. Simultaneously, when the fork is rotated by an external force, the lower partition and the scraper sleeve fixed to it will rotate together. During operation, the scraper sleeve typically moves up and down first, and then rotates as needed when it reaches the designated position. These two actions are usually performed independently and do not interfere with each other. Theoretically, to achieve an ideal cleaning effect during backwashing, the scraper sleeve can rotate as many times as possible.

[0025] In the recommended embodiment, the filter body includes a valve head and a filter bottle connected to each other, and the backwash filter also includes an inner liner installed at the bottom of the filter bottle, the inner liner being sealed and fitted to the inner wall of the filter bottle; the inner wall of the inner liner has an upper sealing section and a drain section located below the sealing section; the lower partition can be sealed and fitted with the sealing section, and the drain section is provided with a drain hole;

[0026] When the lower partition is located in the sealed section, the water pressure chamber and the sewage discharge chamber are separated;

[0027] When the lower partition is located in the sewage discharge section, the water pressure chamber and the sewage discharge chamber are connected through the sewage discharge hole.

[0028] Without considering the addition of an inner liner, the lower partition of the present invention can also be directly sealed to the inner wall of the filter bottle, and the same technical effect as this embodiment can be achieved by opening a drain groove (equivalent to a drain hole) on the inner wall of the filter bottle.

[0029] The reason for adding an inner liner is mainly based on the compatibility with existing filter bottles. That is, without changing the existing filter bottles, adding an inner liner is the most cost-effective way to save on production and processing costs.

[0030] In the recommended embodiment, the inner bushing and the shift fork are integrally formed, with the lower end of the inner bushing connected to the inner tube sleeve. This integral forming helps save on mold and production costs.

[0031] In the recommended implementation, the reset component is a reset spring or two repulsive magnets.

[0032] In the recommended embodiment, the upper part of the wall of the sewage discharge chamber is provided with an antifreeze vent. The diameter of the antifreeze vent is approximately 0.5 mm, typically less than or equal to 0.5 mm, through which the sewage discharge chamber communicates with the outside air.

[0033] During normal backflushing process:

[0034] When the drain outlet (ball valve) is opened, sewage enters the drain chamber from the water pressure chamber and is discharged from the drain outlet. During this process, although the sewage flows through the antifreeze vent, a water film forms on the inner side of the antifreeze vent due to its small diameter, preventing the sewage from flowing out of the vent.

[0035] When the drain outlet (ball valve) is closed, some sewage will remain in the drain chamber. At this time, the upper part of the drain chamber is air and the lower part is sewage. Since the antifreeze vent is located in the upper part of the drain chamber, under normal storage conditions, the antifreeze vent is separated from the sewage.

[0036] Therefore, it can be concluded that during the backwashing process (when the drain outlet is open) and after the backwashing is completed (when the drain outlet is closed), sewage will not flow out from the antifreeze vent.

[0037] When the pre-filter freezes with the drain outlet closed:

[0038] The volume of the medium (water) inside the filter body will inevitably expand, causing the lower partition to move downward, which in turn compresses the air in the drain chamber.

[0039] When the drain chamber is not equipped with antifreeze vents, although the lower partition will also move downward and increase the volume above the lower partition, thus achieving a certain antifreeze effect, the drain chamber is a closed space at this time, and the air inside can only be partially compressed. The distance the lower partition moves downward is small, so the antifreeze effect is poor under these circumstances.

[0040] When antifreeze vents are installed on the drain chamber, the air inside can theoretically be completely discharged because the drain chamber is connected to the outside. This allows the lower partition to move down a sufficient distance, thereby maximizing the volume above the lower partition and achieving the desired antifreeze effect.

[0041] Compared with the prior art, the technical solution provided by this invention has the following advantages: when the flow channel switching part of this invention rises, it forms a filtration state; when the flow channel switching part falls, it enters a backwashing state; it is completely opposite to the movement mode of the prior art and provides a brand-new design concept. Attached Figure Description

[0042] Figure 1 This is a cross-sectional structural diagram of a preferred embodiment in the filtering state.

[0043] Figure 2 This is a cross-sectional structural diagram of a preferred embodiment in the backwashing state.

[0044] Figure 3 This is a three-dimensional structural diagram of the filter cartridge assembly and water distributor.

[0045] Figure 4This is a three-dimensional structural diagram of the flow channel switching section.

[0046] Figure 5 This is a three-dimensional structural diagram of the scraper sleeve and the lower partition.

[0047] Figure 6 This is a schematic diagram of the three-dimensional structure of the base.

[0048] Figure 7 This is a three-dimensional structural diagram of the internal components of the filter body in the filtration state.

[0049] Figure 8 This is a three-dimensional structural diagram of the internal components of the filter body in the backwashing state.

[0050] Figure 9 This is a schematic diagram of the structure of Example 2.

[0051] Figure 10 This is a schematic diagram of the structure of Example 3.

[0052] Figure 11 This is a schematic diagram of the structure of Example 4. Detailed Implementation

[0053] To further understand the content of this invention, the invention will be described in detail with reference to the embodiments. The following embodiments are used to illustrate the invention, but are not intended to limit the scope of the invention.

[0054] Preferred embodiment

[0055] Simultaneously refer to Figure 1 , Figure 2 and Figure 6 A backwashing pre-filter includes a filter body, a water distributor 3 with water distribution holes 31, a filter element assembly 4, a flow channel switching part 7, a power component, a base 6, a rotating housing 101, and a ball valve 102.

[0056] The filter body includes a valve head 1 and a filter bottle 2. The valve head 1 includes a fluid inlet 11 on the left, a fluid outlet 12 on the right, a lower port with internal threads (not shown in the figure), and a flow-blocking sleeve with an opening facing downwards (not shown in the figure). The upper end of the filter bottle 2 is threaded to the lower port of the valve head 1, and the lower end of the filter bottle 2 forms a drain port 13.

[0057] Reference Figure 3The filter element assembly 4 is fixedly installed in the filter body via a water distributor 3. The water distributor 3 is annular and surrounds the upper periphery of the filter element assembly 4. The inner end of the water distributor 3 is fixedly connected to the upper part of the filter element assembly 4, and the outer end of the water distributor 3 is fixedly connected to the inner wall of the filter body. The water distributor 3 is positioned between the filter element assembly 4 and the filter body, and has spaced water distribution holes 31. The filter element assembly 4 includes an upper frame and a lower frame that interlock with each other. In this embodiment, the water distributor 3 is integrally formed with the upper frame. The outer end of the water distributor 3 is fixed to the filter body by engaging the groove of the filter bottle 2 (not shown in the figure) with an outer protrusion 32, ensuring that the filter element assembly 4 and the water distributor 3 do not rotate in the circumferential direction. After assembly, the upper port of the filter element assembly 4 is sealed against the flow-blocking sleeve of the valve head 1, thereby ensuring that, in the filtration state, the water flowing into the filter body from the fluid inlet must be filtered by the filter element assembly 4 before flowing out from the fluid outlet 12.

[0058] The valve head 1, filter bottle 2, filter element assembly 4, and water distributor 3, and their assembly methods are conventional technologies in this field, and their specific structures will not be described in detail here.

[0059] The outer side of the filter element assembly 4 forms the raw water chamber (not shown in the figure); the inner side of the filter element assembly forms the purified water chamber (not shown in the figure), and the water distributor 3 further divides the raw water chamber into an upper chamber 51 and a lower chamber 52.

[0060] Simultaneously refer to Figure 1 , Figure 2 and Figure 5 The power assembly is installed inside the filter body and includes a scraper sleeve 8, a lower partition 9, and a return spring 100 connected to each other. The upper end of the scraper sleeve 8 is connected to the flow channel switching part 7, and the lower end of the scraper sleeve 8 is fixedly connected to the lower partition 9. In this embodiment, the scraper sleeve 8 and the lower partition 9 are integrally formed. The lower partition 9 has a recessed spring mounting groove 91 in the middle of its bottom surface, and a blind insertion hole 92 near the periphery on its bottom surface. The lower partition 9 is located below the filter element assembly 4 and can seal and divide the lower cavity 52 into an upper water pressure chamber 53 and a lower sewage discharge chamber 54, which communicates with the sewage discharge port 13.

[0061] Continue to refer to Figure 4 and Figure 5The flow channel switching part 7 includes a sealing ring 71 and four mutually spaced lower hook parts 72, which are integrally formed. The sealing ring 71 is located above the water distributor 3 and surrounds the filter element assembly 4. The width of the sealing ring 71 is greater than the width of the water distribution holes 31, and it can seal all the water distribution holes 31 when it moves downward. The upper end of each lower hook part 72 is fixedly connected to the bottom surface of the sealing ring 71. The lower hook part 72 includes an arc-shaped connecting piece 721 and a hook 722 that are connected to each other. The thickness of the arc-shaped connecting piece 721 is less than the width of the water distribution hole 31. The upper end of the scraper sleeve 8 is provided with an upper annular groove 80. During installation, the sealing ring 71 is located directly above the water distributor 3, and each lower hook part 72 passes through the corresponding water distribution hole 31 of the water distributor 3 from top to bottom. The number of lower hook parts 72 is less than or equal to the number of water distribution holes 31, for example: refer to Figure 3 and Figure 4 This embodiment has eight water distribution holes 31, but only four lower hook portions 72. The lower hook portions 72 are engaged with the upper annular groove 80, the scraper sleeve 8 is hung on the lower hook portions 72, and the integrally formed scraper sleeve 8 and the lower partition 9 can rotate relative to the lower hook portions 72.

[0062] Reference Figure 6 In this embodiment, the base 6 is integrally formed from a fork and an inner sleeve 61. The fork includes an inner tube sleeve 62 and a rod 63. The upper part of the inner tube sleeve 62 is sealed and installed inside the drain port 13 at the lower end of the filter bottle 2. The lower part of the inner tube sleeve 62 extends out of the drain port 13, and its outer side is provided with several vertical protrusions 64. The rotating sleeve 101 is fitted onto the lower part of the inner tube sleeve 62 and can cooperate with the protrusions 64 to drive the base 6 to rotate as a whole. The top surface of the inner tube sleeve 62 is provided with four limiting protrusions 65. The lower end of the return spring 100 is engaged with the limiting protrusions 65. The upper end of the return spring 100 extends into the spring assembly groove 91 and abuts against the bottom surface of the lower partition 9. During operation, the ball valve 102 is opened, and sewage is discharged from the inner channel of the inner pipe sleeve 62. In addition, the insertion rod 63 protrudes from the top surface of the inner pipe sleeve 62 and is inserted into the insertion blind hole 92 of the corresponding lower partition 9.

[0063] Continue to refer to Figure 6 The inner liner 61 is bowl-shaped and fits snugly against the inner wall of the filter bottle 2. The lower partition 9 always moves within the inner liner 61. The inner wall of the inner liner 61 has an upper sealing section 611 and a drain section 612 located below the sealing section (the sealing section 611 and the drain section 612 are separated by the dotted line in the figure). The sealing section 611 is a straight sidewall, and the lower partition 9 can be sealed with the sealing section 611 by a sealing ring 90. The drain section 612 can be an arc-shaped sidewall, and the drain section 612 is provided with drain holes 610. In this embodiment, there are two symmetrical drain holes 610, which can be set according to actual needs.

[0064] When the lower partition 9 is located in the sealing section 611, the water pressure chamber 53 and the sewage discharge chamber 54 are separated;

[0065] When the lower partition 9 is located in the sewage discharge section 612, the water pressure chamber 53 and the sewage discharge chamber 54 are connected through the sewage discharge hole 610.

[0066] The specific operation process of this invention is as follows:

[0067] Simultaneously refer to Figure 7 When the ball valve 102, which is connected to the drain outlet 13, is closed, the return spring 100 simultaneously pushes the lower partition 9 and the scraper sleeve 8 upwards. The scraper sleeve 8 then drives the flow channel switching part 7 upwards. At this time, the sealing ring 71 moves upwards to directly above the water distribution hole 31, making the upper cavity 51 and the lower cavity 52 interconnected. Meanwhile, the lower partition 9 is located inside the sealing section 611, separating the water pressure chamber 53 and the drain chamber 54. At this time, water flows from the fluid inlet 11 into the upper cavity 51 and the lower cavity 52, then enters the clean water chamber from the upper cavity 51 and the lower cavity 52 respectively, and finally flows out from the fluid outlet 12 through the clean water chamber; thus, the filtration process is completed.

[0068] Simultaneously refer to Figure 8 When the ball valve 102, which is connected to the drain outlet 13, is opened, the pressure difference between the water pressure chamber 53 and the drain chamber 54 is greater than the restoring force of the return spring 100. The pressure difference pushes the lower partition 9, together with the scraper sleeve 8, down to the drain section 612, thus connecting the water pressure chamber 53 and the drain chamber 54. At the same time, the scraper sleeve 8 and the lower partition 9 move down, causing the flow channel switching part 7 to move down simultaneously. The sealing ring 71 seals the water distribution hole 31 of the water distributor 3, thereby separating the upper chamber 51 and the lower chamber 52. At this time, water flows into the upper chamber 51 from the fluid inlet 11, then flows into the clean water chamber from the upper chamber 51, then into the lower chamber 52 from the clean water chamber, and finally exits from the drain outlet 13 through the lower chamber 52, thus completing the backwashing process.

[0069] This embodiment fully utilizes the pressure difference between the upper and lower parts of the lower partition 9. In use, only the opening / closing of the drain port 13 needs to be controlled, that is, usually only the opening / closing of the ball valve 102 needs to be controlled, to switch between the filtration state and the backwashing state. This achieves the effect of "one-button backwashing".

[0070] In addition, when the rotating sleeve 101 rotates, it can cooperate with the protrusion 64 of the inner tube sleeve to drive the bottom support 6 to rotate as a whole. The insertion rod 63 of the bottom support 6 is inserted into the insertion blind hole 92 of the lower partition 9. Therefore, when the rotating sleeve 101 rotates, the lower partition 9 and the scraper sleeve 8 integrally formed with the lower partition 9 will also rotate together (in this process, since the upper annular groove 80 of the scraper sleeve 8 is only attached to the lower hook part 72 of the flow channel switching part 7, the flow channel switching part 7 will not rotate with the scraper sleeve 8), thereby achieving the purpose of scraping and washing the filter bottle 2 and the filter element assembly 4.

[0071] In this embodiment, the scraper sleeve 8 moves up and down together with the lower partition 9. When an external force rotates the rotating housing 101, the lower partition 9 and the integral scraper sleeve 8 will also rotate together. During operation, the scraper sleeve 8 typically moves up and down first, and then rotates as needed when it reaches the designated position. These two actions are usually performed independently and do not interfere with each other. Theoretically, to achieve an ideal cleaning effect during backwashing, the scraper sleeve 8 can rotate as many times as possible.

[0072] Reference Figure 5 In the recommended embodiment, the scraper sleeve 8 includes a scraper frame 81 and multiple scraper rubber rings 82. The scraper frame 81 is a hollow cylindrical shape with multiple parallel mounting grooves 83. The scraper rubber rings 82 are respectively fitted onto the mounting grooves 83. As can be seen from the figure, the inner wall of the scraper rubber ring 82 is provided with scraper teeth 84 at intervals, and the outer wall of the scraper rubber ring 82 is provided with scraper blades 85 at intervals, thus enabling simultaneous scraping of the filter bottle 2 and the filter element assembly 4.

[0073] This embodiment adopts a "double-sided scraper" structure. When the scraper sleeve 8 rotates, it can clean the filter bottle 2 and the filter element assembly 4 at the same time, which has an ideal cleaning effect.

[0074] Although the "double-sided scraper" increases the friction of the scraper sleeve 8 moving up and down compared to the "single-sided scraper (scraping only the filter element or only the filter bottle)," and inevitably requires higher water pressure, the scraper sleeve 8 made of all-plastic material is relatively light. Therefore, even in the case of low water pressure (0.5 kg to 1 kg), it can still switch between filtration and backwashing states by opening / closing the drain port, thus achieving the purpose of "one-button backwashing."

[0075] Example 2

[0076] Reference Figure 9This embodiment has a structure that is basically the same as the preferred embodiment described above. The main difference is that this embodiment has an antifreeze vent 20 on the upper part of the wall of the drain chamber 54 (filter bottle 2). The diameter of the antifreeze vent 20 is about 0.5 mm, usually less than or equal to 0.5 mm. Through the antifreeze vent 20, the drain chamber 54 is connected to the outside air.

[0077] During normal backflushing process:

[0078] When ball valve 102 is opened, sewage enters drain chamber 54 from water pressure chamber 53 and is discharged from drain port 13. During this process, although sewage will flow through antifreeze vent 20, because the diameter of antifreeze vent 20 is very small, a water film will form on the inner port of antifreeze vent 20, so sewage will not flow out of antifreeze vent 20.

[0079] When the ball valve 102 is closed, some sewage will remain in the drain chamber 54. At this time, the upper part of the drain chamber 54 is air and the lower part is sewage. Since the antifreeze vent 20 is located in the upper part of the drain chamber 54, under the above storage conditions, the antifreeze vent 20 is separated from the sewage.

[0080] Therefore, it can be seen that during the backwashing process (when ball valve 102 is open) and after the backwashing is completed (when ball valve 102 is closed), sewage will not flow out from the antifreeze vent 20.

[0081] When the pre-filter freezes with ball valve 102 closed:

[0082] The volume of the medium (water) inside the filter body will inevitably expand, causing the lower partition 9 to move downward, which compresses the air in the drain chamber 54.

[0083] When the drain chamber 54 is not equipped with antifreeze vents 20, although the lower partition 9 will also move down and increase the volume above the lower partition 9 to achieve a certain antifreeze effect, the drain chamber 54 is a closed space at this time, and the air inside can only be partially compressed. The lower partition 9 moves down a small distance, so the antifreeze effect is poor under these circumstances.

[0084] When the drain chamber 54 is equipped with an antifreeze vent 20, since the drain chamber 54 is connected to the outside, the air inside can theoretically be completely discharged, allowing the lower partition 9 to move down a sufficient distance, thereby maximizing the volume above the lower partition 9 and achieving an ideal antifreeze effect.

[0085] Example 3

[0086] Reference Figure 10The structure of this second embodiment is basically the same as that of the preferred embodiment above. The main difference is that the power assembly of this embodiment includes a scraper sleeve 8, a base plate 1a and a lead screw assembly. The upper end of the scraper sleeve 8 is rotatably connected to the flow channel switching part 7, and the lower end of the scraper sleeve 8 is integrally formed with the base plate 1a. The base plate 1a is provided with a plug-in through hole (not shown in the figure).

[0087] The lead screw assembly includes a lead screw 1b that protrudes from the upper surface of the base plate 1a and an internal threaded sleeve 1c that is recessed into the bottom of the filter element assembly 4. The lead screw 1b is threadedly connected to the internal threaded sleeve 1c.

[0088] The power assembly in this embodiment also includes a shift fork 1d and a rotating housing 101. The shift fork 1d includes an inner tube sleeve 1e and a rod 1f. The upper part of the inner tube sleeve 1e is sealed and installed inside the drain port 13 at the lower end of the filter bottle 2, and the lower part of the inner tube sleeve 1e extends out of the drain port 13. Several vertical protrusions are provided on its outer side. The rotating housing 101 is fitted onto the lower part of the inner tube sleeve 1e and can work with the protrusions to drive the base plate and the scraper sleeve 8 to rotate together. The rod 1f protrudes from the top surface of the inner tube sleeve and passes through the insertion through hole of the corresponding base plate 1a.

[0089] The operation process in this embodiment is as follows:

[0090] The rotating housing 101 rotates, causing the shift fork 1d to rotate. The shift fork 1d then drives the base plate 1a, the scraper sleeve 8, and the lead screw 1b on the base plate 1a to rotate. Since the filter element assembly 4 is fixed in the filter body, when the lead screw 1b rotates in the internal threaded sleeve 1c of the filter element assembly 4, the base plate 1a, the lead screw 1b, and the scraper sleeve 8 will move axially while rotating, thereby driving the flow channel switching part 7 to move up and down, thus realizing the switching of the flow channel.

[0091] In the filtration state, the ball valve 102 is closed, and the power unit drives the flow channel switching part 7 to move upward.

[0092] In the backwashing state, the ball valve 102 is opened, and the power unit drives the flow channel switching part 7 to move downward.

[0093] Example 4

[0094] Reference Figure 11 This embodiment is basically the same as the structure of the above embodiment 2. The main difference is that the brush sleeve is replaced by a simpler connector 2a in this embodiment 3. The connector 2a includes several connecting rods 2b and an annular connecting part 2c at the upper end. The annular connecting part 2c is provided with an upper annular groove (not shown in the figure) for cooperating with the flow channel switching part 7. The upper end of each connecting rod 2b is connected to the annular connecting part 2c, and the lower end of each connecting rod 2b is integrally connected to the base plate 1a.

[0095] The operation process in this embodiment is similar to that in Embodiment 2 above, and will not be described again here.

[0096] The present invention has been described in detail above with reference to the embodiments, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made in accordance with the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A backwashing pre-filter, comprising a filter element assembly, a water distributor with water distribution holes, and a filter body having a fluid inlet, a fluid outlet, and a drain outlet, wherein the filter element assembly is installed within the filter body, a raw water chamber is formed on the outer side of the filter element assembly, and a clean water chamber is formed on the inner side of the filter element assembly; the water distributor is positioned between the filter element assembly and the filter body, and the water distributor divides the raw water chamber into an upper chamber and a lower chamber, characterized in that: The backwash pre-filter also includes a flow channel switching part installed in the filter body and a power component for moving the flow channel switching part. Filtration state: The flow channel switching part moves upward relative to the water distributor, so that the upper and lower chambers are connected to each other; the fluid flows into the upper and lower chambers from the fluid inlet, then enters the clean water chamber from the upper and lower chambers, and finally flows out from the fluid outlet through the clean water chamber; Backwashing state: The flow channel switching part moves downward relative to the water distributor, so that the upper and lower chambers are separated from each other; the fluid enters the upper chamber from the fluid inlet, then flows into the clean water chamber from the upper chamber, then enters the lower chamber from the clean water chamber, and finally exits from the drain outlet through the lower chamber. The power assembly includes a reset assembly with restoring force and a lower partition, which can divide the lower cavity into an upper water pressure chamber and a lower sewage discharge chamber, and the sewage discharge chamber is connected to the sewage discharge port. The power assembly also includes a cylindrical scraper sleeve, the upper end of which is rotatably connected to the flow channel switching part, and the lower end of which is fixedly connected to the lower partition part. The filter body includes a valve head and a filter bottle connected to each other. The scraper sleeve includes a cylindrical scraper frame and a scraper part that can scrape the filter bottle and the filter element assembly at the same time. The scraper part is fixedly installed on the scraper frame. The flow channel switching part includes a sealing ring and a lower hook part that are connected to each other. The sealing ring is located directly above the water distributor and can seal the water distribution hole. The lower hook part passes through the water distribution hole of the corresponding water distributor from top to bottom. The upper end of the scraper sleeve is provided with an upper annular groove. The lower hook part is inserted into the upper annular groove and can rotate relative to the lower hook part. The bottom surface of the lower partition is provided with a blind insertion hole; the backwash pre-filter also includes a rotatable fork, the fork including an inner pipe sleeve and a plug rod that are fixedly connected to each other, the inner pipe sleeve is sealed and installed in the drain port, and the plug rod is inserted into the corresponding blind insertion hole; The filter body includes a valve head and a filter bottle connected to each other. The backwash filter also includes an inner liner installed at the bottom of the filter bottle. The inner liner is sealed and fitted to the inner wall of the filter bottle. The inner wall of the inner liner has an upper sealing section and a drain section located below the sealing section. The lower partition can be sealed and fitted with the sealing section. The drain section is provided with a drain hole. When the lower partition is located in the sealed section, the water pressure chamber and the sewage discharge chamber are separated; When the lower partition is located in the sewage discharge section, the water pressure chamber and the sewage discharge chamber are connected through the sewage discharge hole; The upper part of the wall of the sewage discharge chamber is provided with antifreeze vents.

2. The backwash pre-filter according to claim 1, characterized in that: When the drain outlet is closed, the reset assembly pushes the lower partition upward, separating the water pressure chamber and the drain chamber; at the same time, the lower partition drives the flow channel switching part to move upward, so that the upper and lower chambers are connected to each other; When the drain outlet is opened, the pressure difference between the water pressure chamber and the drain chamber is greater than the restoring force of the reset component. The pressure difference presses down the lower partition and connects the water pressure chamber and the drain chamber. At the same time, the lower partition drives the flow channel switching part to move downward, thus separating the upper and lower cavities.

3. The backwash pre-filter according to claim 2, characterized in that: The inner liner and the shift fork are integrally formed, and the lower end of the inner liner is connected to the inner tube sleeve.

4. The backwash pre-filter according to claim 2, characterized in that: The reset component is a reset spring or two repulsive magnets.

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