Automatic online backwashing system of plate heat exchanger

Abstract

The utility model discloses an automatic online backwashing system of a plate heat exchanger, and belongs to the technical field of heat supply. The system comprises a first-level network water supply main pipe, a first-level network water return main pipe, a second-level network water supply main pipe, a second-level network water return main pipe, a plate heat exchanger first-level network water supply pipeline, a plate heat exchanger first-level network water return pipeline, a plate heat exchanger second-level network water supply pipeline, a plate heat exchanger second-level network water return pipeline, a plate heat exchanger and a logic control system. The utility model aims to solve the problems that a water flow pulse effect can be realized by utilizing the quick-opening and quick-closing functions of the pulse backwashing device by inputting a large amount of manpower, and the dirt washing effect can be greatly improved by continuously vibrating and impacting high and low pressure. An inlet door and a blow-down door of the plate heat exchanger are changed into electric valves, and pressure difference or logarithmic average temperature difference monitoring is set, so that the dynamic online backwashing function can be realized, the manufacturing cost is low, and the transformation is convenient.

Description

Technical Field

[0001] The utility model relates to an automatic online backwashing system for a plate heat exchanger, belonging to the technical field of heating. Background Art

[0002] At present, plate heat exchangers are very easy to get clogged as they run for a long time and need to be backwashed regularly. The conventional backwashing method is to close the inlet door of the plate heat exchanger and use reverse water flow to flush it, which requires regular manual operation. At the same time, since the dirt is sticky, it is often difficult to flush it clean by relying on the static pressure of the pipe. As the heating area increases year by year, the number of equipment is increasing, and the demand for staff with operational capabilities is increasing. At present, the match between the number of staff and the number of equipment is close to saturation. If we consider increasing manpower from the perspective of ensuring the quality of heating, not only is it difficult to recruit qualified staff, but the operation cycle is long and the cost is high.

[0003] Therefore, it is urgent to propose a new type of unpowered automatic drug delivery device for water treatment of heating system to solve the above technical problems. Utility Model Content

[0004] The purpose of developing the utility model is to solve the problem of investing a lot of manpower, that is, to utilize the fast opening and closing function of the pulse backwashing device to achieve the water flow pulse effect, and to greatly improve the dirt washing effect through continuous oscillation and impact of high and low pressures. By installing a pulse backwashing device in the main pipeline, the inlet door and the sewage door of the plate heat exchanger are changed to electric valves, and the dynamic online backwashing function can be realized by setting the pressure difference or logarithmic mean temperature difference monitoring.

[0005] A brief summary of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this summary is not an exhaustive summary of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0006] The technical solution of this utility model:

[0007] An automatic online backwashing system for a plate heat exchanger, comprising a primary network water supply main pipe, a primary network return water main pipe, a secondary network water supply main pipe, a secondary network return water main pipe, a plate heat exchanger primary network water supply pipe, a plate heat exchanger primary network return water pipe, a plate heat exchanger secondary network water supply pipe, a plate heat exchanger secondary network return water pipe, a plate heat exchanger and a logic control system;

[0008] The primary network water supply main is connected to the primary network water supply pipeline of the plate heat exchanger, the plate heat exchanger is connected to the primary network return water main through the primary network return water pipeline of the plate heat exchanger, the plate heat exchanger is connected to the secondary network water supply main through the secondary network water supply pipeline of the plate heat exchanger, and the plate heat exchanger is connected to the secondary network return water main through the secondary network return water pipeline of the plate heat exchanger. The connection between the plate heat exchanger and the primary network water supply pipeline of the plate heat exchanger and the secondary network water supply pipeline of the plate heat exchanger is provided with a newly added water supply pressure transmitter, and the connection between the plate heat exchanger and the primary network return water pipeline of the plate heat exchanger and the secondary network return water pipeline of the plate heat exchanger is provided with a newly added return water pressure transmitter;

[0009] The plate heat exchanger primary network water supply pipeline is also provided with a plate heat exchanger primary network inlet electric shut-off valve and a plate heat exchanger primary network backwash electric shut-off valve;

[0010] The plate heat exchanger primary network return water pipeline is also provided with a plate heat exchanger primary network outlet electric shut-off valve and a plate heat exchanger primary network automatic pulse backwashing device;

[0011] The plate heat exchanger secondary network water supply pipeline is also provided with a plate heat exchanger secondary network outlet electric shut-off valve and a plate heat exchanger secondary network automatic pulse backwashing device;

[0012] The plate heat exchanger secondary network return water pipeline is also provided with a plate heat exchanger secondary network inlet electric shut-off valve 20 and a plate heat exchanger secondary network backwash electric shut-off valve;

[0013] The logic control system obtains the average pressure difference monitoring result through the newly added return water pressure transmitter and the newly added water supply pressure transmitter. When the average pressure difference monitoring result exceeds the design value, the electric shut-off valve at the inlet of the first-level network of the plate heat exchanger and the electric shut-off valve at the outlet of the second-level network of the plate heat exchanger are automatically closed, and the electric shut-off valve for backwashing of the first-level network of the plate heat exchanger and the electric shut-off valve for backwashing of the second-level network of the plate heat exchanger are opened. The automatic pulse backwashing device of the first-level network of the plate heat exchanger and the automatic pulse backwashing device of the second-level network of the plate heat exchanger are periodically switched on and off to backwash the plate heat exchanger.

[0014] Preferably: the primary network water supply main is provided with a primary network water supply main quick dirt remover and a primary network return water main Y-type filter, the primary network water supply main quick dirt remover is installed with a primary network water supply main quick dirt remover sewage electric shut-off valve, and the primary network return water main Y-type filter is installed with a primary network return water main Y-type filter sewage electric shut-off valve.

[0015] Preferably: a primary network return water main is provided with a primary network return water main temperature sensor, and a secondary network water supply main is provided with a secondary network water supply main temperature sensor. The logic control system obtains the average temperature difference monitoring result through the primary network return water main temperature sensor and the secondary network water supply main temperature sensor. When the average temperature difference monitoring result exceeds the design value, the primary network inlet electric shut-off valve and the secondary network outlet electric shut-off valve of the plate heat exchanger are automatically closed, the primary network backwash electric shut-off valve and the secondary network backwash electric shut-off valve of the plate heat exchanger are opened, and the primary network automatic pulse backwash device and the secondary network automatic pulse backwash device of the plate heat exchanger are periodically switched on and off to backwash the plate heat exchanger.

[0016] Preferably: the secondary network return water main is provided with a secondary network return water main Y-type filter and a secondary network return water main quick dirt remover, the secondary network return water main Y-type filter is provided with a secondary network return water main Y-type filter sewage electric shut-off valve, and the secondary network return water main quick dirt remover is provided with a secondary network return water main quick dirt remover sewage electric shut-off valve.

[0017] The utility model has the following beneficial effects:

[0018] 1. The utility model is an automatic online backwashing system for a plate heat exchanger, which can be equipped with a pulse backwashing device through the main pipeline, and the inlet door and the sewage door of the plate heat exchanger can be changed to electric valves. By setting the pressure difference or logarithmic mean temperature difference monitoring, the dynamic online backwashing function can be realized;

[0019] 2. The utility model is not only low in cost and easy to transform, but also can alleviate the problem of insufficient staff to a certain extent and can effectively improve the problem of long service life and poor heat exchange efficiency of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an automatic online backwashing system for a plate heat exchanger;

[0021] In the figure, 1, primary network water supply main, 2, primary network return main, 3, secondary network water supply main, 4, secondary network return main, 5, plate heat exchanger primary network water supply pipe, 6, plate heat exchanger primary network return pipe, 7, plate heat exchanger secondary network water supply pipe, 8, plate heat exchanger secondary network return pipe, 9, plate heat exchanger, 10, primary network water supply main quick dirt remover, 11, primary network return water main Y-type filter, 12, secondary network return water main Y-type filter, 13, secondary network return water main quick dirt remover, 14, primary network return water main temperature sensor, 15, secondary network supply water main temperature sensor, 16, newly added return water pressure transmitter, 17, newly added water supply pressure transmitter, 18, plate heat exchanger primary network inlet electric 1. Electric shut-off valve, 2. Plate heat exchanger primary network outlet electric shut-off valve, 3. Plate heat exchanger secondary network inlet electric shut-off valve, 4. Plate heat exchanger secondary network outlet electric shut-off valve, 5. Plate heat exchanger primary network automatic pulse backwashing device, 6. Plate heat exchanger primary network backwashing electric shut-off valve, 7. Plate heat exchanger secondary network backwashing electric shut-off valve, 8. Plate heat exchanger primary network return water main pipe quick dirt remover drain electric shut-off valve, 9. Secondary network return water main pipe quick dirt remover drain electric shut-off valve, 10. Logic control system. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is described below by specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the utility model. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.

[0023] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection is a non-detachable connection, including but not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but is not limited to conventional detachable methods such as threaded connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can always be found in the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example: choose welding connection for fixed connection and hinge connection for detachable connection.

[0024] Specific implementation method 1: Combination Figure 1The present embodiment is described. The present embodiment is an automatic online backwashing system for a plate heat exchanger, comprising a primary network water supply main pipe 1, a primary network return water main pipe 2, a secondary network water supply main pipe 3, a secondary network return water main pipe 4, a plate heat exchanger primary network water supply pipe 5, a plate heat exchanger primary network return water pipe 6, a plate heat exchanger secondary network water supply pipe 7, a plate heat exchanger secondary network return water pipe 8, a plate heat exchanger 9 and a logic control system 30;

[0025] The primary network water supply main (1) is connected to the primary network water supply pipeline (5) of the plate heat exchanger, the plate heat exchanger 9 is connected to the primary network return water main 2 through the plate heat exchanger primary network return water pipeline 6, the plate heat exchanger 9 is connected to the secondary network water supply main 3 through the plate heat exchanger secondary network water supply pipeline 7, the plate heat exchanger 9 is connected to the secondary network return water main 4 through the plate heat exchanger secondary network return water pipeline 8, the connection between the plate heat exchanger 9 and the plate heat exchanger primary network water supply pipeline 5 and the plate heat exchanger secondary network water supply pipeline 7 is provided with a newly added water supply pressure transmitter 17, and the connection between the plate heat exchanger 9 and the plate heat exchanger primary network return water pipeline 6 and the plate heat exchanger secondary network return water pipeline 8 is provided with a newly added return water pressure transmitter 16;

[0026] The plate heat exchanger primary network water supply pipeline 5 is also provided with a plate heat exchanger primary network inlet electric shut-off valve 18 and a plate heat exchanger primary network backwash electric shut-off valve 24;

[0027] The plate heat exchanger primary network return water pipe 6 is also provided with a plate heat exchanger primary network outlet electric shut-off valve 19 and a plate heat exchanger primary network automatic pulse backwashing device 22;

[0028] The plate heat exchanger secondary network water supply pipeline 7 is also provided with a plate heat exchanger secondary network outlet electric shut-off valve 21 and a plate heat exchanger secondary network automatic pulse backwashing device 23;

[0029] The plate heat exchanger secondary network return water pipe 8 is also provided with a plate heat exchanger secondary network inlet electric shut-off valve 20 and a plate heat exchanger secondary network backwash electric shut-off valve 25;

[0030] The logic control system 30 obtains the average pressure difference monitoring result through the newly added return water pressure transmitter 16 and the newly added water supply pressure transmitter 17. When the average pressure difference monitoring result of the inlet and outlet pressure difference on one side of the plate heat exchanger 9 exceeds the design value, the plate heat exchanger primary network inlet electric shut-off valve 18 and the plate heat exchanger secondary network outlet electric shut-off valve 21 are automatically closed, the plate heat exchanger primary network backwash electric shut-off valve 24 and the plate heat exchanger secondary network backwash electric shut-off valve 25 are opened, and the plate heat exchanger primary network automatic pulse backwash device 22 and the plate heat exchanger secondary network automatic pulse backwash device 23 are periodically switched on and off to backwash the plate heat exchanger 9.

[0031] The logarithmic mean temperature difference can also be calculated as a monitoring or judgment basis through the primary network return water main temperature sensor 14 and the secondary network water supply main temperature sensor 15, that is, the primary network return water main 2 is provided with a primary network return water main temperature sensor 14, and the secondary network water supply main 3 is provided with a secondary network water supply main temperature sensor 15. The logic control system 30 obtains the average temperature difference monitoring result through the primary network return water main temperature sensor 14 and the secondary network water supply main temperature sensor 15. When the average temperature difference monitoring result exceeds the design value, the electric shut-off valve 18 of the primary network inlet of the plate heat exchanger and the secondary network outlet of the plate heat exchanger are automatically closed. The electric shut-off valve 21 opens the electric shut-off valve 24 for backwashing the primary network of the plate heat exchanger and the electric shut-off valve 25 for backwashing the secondary network of the plate heat exchanger. The automatic pulse backwashing device 22 for the primary network of the plate heat exchanger and the automatic pulse backwashing device 23 for the secondary network of the plate heat exchanger are periodically switched on and off to backwash the plate heat exchanger 9. The periodic switch is a fast periodic rapid opening and closing device, which is used to form a strong pulse water flow through the rapid opening and closing of the automatic pulse backwashing device 22 for the primary network of the plate heat exchanger and the automatic pulse backwashing device 23 for the secondary network of the plate heat exchanger. Through continuous oscillation and impact of high and low pressures, the dirt washing effect can be greatly improved.

[0032] By replacing the electric shut-off valve 18 at the inlet of the plate heat exchanger primary network and the electric shut-off valve 19 at the outlet of the plate heat exchanger primary network, the electric shut-off valve 20 at the inlet of the plate heat exchanger secondary network and the electric shut-off valve 21 at the outlet of the plate heat exchanger secondary network, the electric shut-off valve 24 for backwashing of the plate heat exchanger primary network and the electric shut-off valve 25 for backwashing of the plate heat exchanger secondary network, the remote or automatic switching function is realized, providing the basic conditions for automatic backwashing

[0033] The primary network water supply main pipe 1 is provided with a primary network water supply main pipe quick dirt remover 10 and a primary network return water main pipe Y-type filter 11. The primary network water supply main pipe quick dirt remover 10 is installed with a primary network water supply main pipe quick dirt remover sewage electric shut-off valve 27, and the primary network return water main pipe Y-type filter 11 is installed with a primary network return water main pipe Y-type filter sewage electric shut-off valve 26.

[0034] The secondary network return water main pipe 4 is provided with a secondary network return water main pipe Y-type filter 12 and a secondary network return water main pipe quick dirt remover 13, the secondary network return water main pipe Y-type filter 12 is provided with a secondary network return water main pipe Y-type filter sewage electric shut-off valve 28, and the secondary network return water main pipe quick dirt remover 13 is provided with a secondary network return water main pipe quick dirt remover sewage electric shut-off valve 29.

[0035] By replacing the electric shut-off valve 27 for the quick dirt collector of the primary network water supply main, the electric shut-off valve 26 for the Y-type filter of the primary network return water main, the electric shut-off valve 29 for the quick dirt collector of the secondary network return water main, and the electric shut-off valve 28 for the Y-type filter of the secondary network return water main, the purpose of reducing the blockage rate of the plate heat exchanger by remotely or automatically switching on and off the dirt discharge can be achieved.

[0036] Under normal working conditions, the pressure difference between the front and rear of the plate heat exchanger 9 is below 0.03MPa. The plate heat exchanger 9 is very easy to be blocked as the operation time increases, and needs to be backwashed regularly. The conventional backwashing method is to close the electric shut-off valve 18 at the inlet of the plate heat exchanger primary network and the electric shut-off valve 20 at the inlet of the plate heat exchanger secondary network, and use reverse water flow for flushing, which requires manual regular operation. At the same time, since the dirt is sticky, it is difficult to flush it clean by pipeline static pressure in most cases. Through the automatic pulse backwashing device 22 of the plate heat exchanger primary network and the automatic pulse backwashing device 20 of the plate heat exchanger secondary network, the plate heat exchanger primary network is automatically backwashed. The rapid opening and closing of the washing device 23 forms a strong pulse water flow, which can greatly improve the dirt washing effect through continuous oscillation and impact of high and low pressures. It can be seen that pulse washing has better descaling and dirt removal capabilities than conventional backwashing. From a mechanical point of view, pulse backwashing is fully capable of cleaning the plate heat exchanger 9. Therefore, this embodiment can not only meet the cleaning needs of the plate heat exchanger based on the rapid opening and closing function and remote automatic control function of the pulse backwashing device, but also reduce labor, reduce heat waste and human resource waste, and improve energy utilization.

[0037] This embodiment can also be modified based on the existing operating units. During the modification, in view of the large difference between the blockage of some units and the heat exchange efficiency, from the aspects of economy, aspect, and modification difficulty, the plate heat exchanger 9 can be selected according to the actual logarithmic temperature difference and front-to-back pressure difference of each heat exchange station. The unit with a pressure difference of one side of the inlet and outlet of the plate heat exchanger 9 is greater than 0.05Mpa under normal conditions, or the logarithmic mean temperature difference exceeds the design value for modification. If the unit with more water loss is modified, there is a certain probability of instantaneous pressure loss during backwashing due to frequent pressure drop and other related problems, resulting in a large area of ​​users not being heated, causing great public opinion risks. Therefore, this modification plan is suitable for units with frequent blockage of plate heat exchangers and relatively stable unit pressure;

[0038] Taking the geothermal unit in the central area of ​​a heat exchange station of a heating company as an example, after the transformation, the inlet pressure of the first-level network of the plate heat exchanger 9 is 0.78Mpa, the outlet pressure of the first-level network of the plate heat exchanger 9 is 0.76Mpa, the outlet pressure of the second-level network of the plate heat exchanger 9 is 0.87Mpa, the inlet pressure of the second-level network of the plate heat exchanger 9 is 0.85Mpa, the return water temperature of the first-level network is 45℃, and the water supply temperature of the second-level network is 50℃, which meets the requirements of negative logarithmic temperature difference and front and rear pressure difference <0.05Mpa. After the implementation of this project, on the one hand, the backwashing effect of the plate heat exchanger can be greatly improved through the pulse oscillation effect, and the efficiency of the heat exchanger can be improved. At the same time, the frequency of mechanical disassembly of the plate heat exchanger is reduced, the risk of damage to the plates and rubber strips is reduced, and the reliability of the equipment is improved. On the other hand, the status of the plate heat exchanger 9 can be monitored, and the heat exchange effect of the plate heat exchanger 9 can be dynamically judged. At the same time, remote automatic backwashing can be achieved through automatic control, which greatly reduces labor costs and solves the problem that the heating company has too many plate heat exchangers 9 and untimely cleaning.

[0039] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present utility model will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present utility model.

[0040] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. An automatic online backwashing system for a plate heat exchanger, characterized in that: It comprises a primary network water supply main pipe (1), a primary network return water main pipe (2), a secondary network water supply main pipe (3), a secondary network return water main pipe (4), a plate heat exchanger primary network water supply pipe (5), a plate heat exchanger primary network return water pipe (6), a plate heat exchanger secondary network water supply pipe (7), a plate heat exchanger secondary network return water pipe (8), a plate heat exchanger (9) and a logic control system (30); The primary network water supply main pipe (1) is connected to the primary network water supply pipe (5) of the plate heat exchanger, the plate heat exchanger (9) is connected to the primary network water return main pipe (2) through the primary network water return pipe (6) of the plate heat exchanger, the plate heat exchanger (9) is connected to the secondary network water supply main pipe (3) through the secondary network water supply pipe (7) of the plate heat exchanger, and the plate heat exchanger (9) is connected to the secondary network water return main pipe (4) through the secondary network water return pipe (8) of the plate heat exchanger. A newly added water supply pressure transmitter (17) is provided at the connection between the plate heat exchanger (9) and the primary network water supply pipe (5) of the plate heat exchanger and the secondary network water supply pipe (7) of the plate heat exchanger, and a newly added return water pressure transmitter (16) is provided at the connection between the plate heat exchanger (9) and the primary network water return pipe (6) of the plate heat exchanger and the secondary network water return pipe (8) of the plate heat exchanger; The plate heat exchanger primary network water supply pipeline (5) is also provided with a plate heat exchanger primary network inlet electric shut-off valve (18) and a plate heat exchanger primary network backwash electric shut-off valve (24); The plate heat exchanger primary network return water pipe (6) is also provided with a plate heat exchanger primary network outlet electric shut-off valve (19) and a plate heat exchanger primary network automatic pulse backwashing device (22); The plate heat exchanger secondary network water supply pipeline (7) is also provided with a plate heat exchanger secondary network outlet electric shut-off valve (21) and a plate heat exchanger secondary network automatic pulse backwashing device (23); The plate heat exchanger secondary network return water pipe (8) is also provided with a plate heat exchanger secondary network inlet electric shut-off valve (20) and a plate heat exchanger secondary network backwash electric shut-off valve (25); The logic control system (30) obtains the average pressure difference monitoring result through the newly added return water pressure transmitter (16) and the newly added water supply pressure transmitter (17). When the average pressure difference monitoring result exceeds the design value, the electric shut-off valve (18) at the inlet of the plate heat exchanger primary network and the electric shut-off valve (21) at the outlet of the plate heat exchanger secondary network are automatically closed, the electric shut-off valve (24) for backwashing of the plate heat exchanger primary network and the electric shut-off valve (25) for backwashing of the plate heat exchanger secondary network are opened, and the automatic pulse backwashing device (22) for the plate heat exchanger primary network and the automatic pulse backwashing device (23) for the plate heat exchanger secondary network are periodically turned on and off to backwash the plate heat exchanger (9).

2. The automatic online backwashing system for a plate heat exchanger according to claim 1, characterized in that: The primary network water supply main pipe (1) is provided with a primary network water supply main pipe quick dirt remover (10) and a primary network return water main pipe Y-type filter (11); the primary network water supply main pipe quick dirt remover (10) is installed with a primary network water supply main pipe quick dirt remover sewage discharge electric shut-off valve (27); the primary network return water main pipe Y-type filter (11) is installed with a primary network return water main pipe Y-type filter sewage discharge electric shut-off valve (26).

3. The automatic online backwashing system for a plate heat exchanger according to claim 2, characterized in that: The primary network return water main pipe (2) is provided with a primary network return water main pipe temperature sensor (14), and the secondary network water supply main pipe (3) is provided with a secondary network water supply main pipe temperature sensor (15). The logic control system (30) obtains the average temperature difference monitoring result through the primary network return water main pipe temperature sensor (14) and the secondary network water supply main pipe temperature sensor (15). When the average temperature difference monitoring result exceeds the design value, the plate heat exchanger primary network inlet electric shut-off valve (18) and the plate heat exchanger secondary network outlet electric shut-off valve (21) are automatically closed, the plate heat exchanger primary network backwashing electric shut-off valve (24) and the plate heat exchanger secondary network backwashing electric shut-off valve (25) are opened, and the plate heat exchanger primary network automatic pulse backwashing device (22) and the plate heat exchanger secondary network automatic pulse backwashing device (23) are periodically turned on and off to backwash the plate heat exchanger (9).

4. The automatic online backwashing system for a plate heat exchanger according to claim 3, characterized in that: The secondary network return water main pipe (4) is provided with a secondary network return water main pipe Y-type filter (12) and a secondary network return water main pipe quick dirt remover (13); the secondary network return water main pipe Y-type filter (12) is provided with a secondary network return water main pipe Y-type filter sewage electric shut-off valve (28); the secondary network return water main pipe quick dirt remover (13) is provided with a secondary network return water main pipe quick dirt remover sewage electric shut-off valve (29).

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