Pre-pump foot valve and system, method of connecting a pump to draw a liquid

Abstract

The application discloses a pump front bottom valve, a system and a method for connecting a pump to extract liquid, and the pump front bottom valve comprises a valve cover, a valve body, a piston rod and a pressing plate; the valve body is provided with a bottom valve inlet and a bottom valve outlet, and a cut-off port is arranged between the bottom valve inlet and the bottom valve outlet; a top inner space is formed at the position of the valve cavity relative to the valve cover; the bottom valve inlet is connected to the top inner space through a connecting pipeline, and a check valve is arranged on the connecting pipeline, and fluid can enter the top inner space from the bottom valve inlet along the connecting pipeline through the check valve. The application solves the problem of the limitation of the prior art on the position of the centrifugal pump above the liquid surface.

Description

Technical Field

[0001] This invention relates to a bottom valve before a liquid pump and a system and method for connecting a pump to draw liquid using the same valve, belonging to the field of liquid valves. Background Technology

[0002] In the existing technology, there are several ways to achieve liquid delivery by centrifugal pumps positioned above the liquid surface: installing a foot valve, installing a circulating pump, using a vacuum pump to create a vacuum, or installing a water-based foot valve. However, these solutions all have limitations in their application.

[0003] I. Defects of installing a foot valve:

[0004] 1. When used in high-lift applications, water hammer may occur in the pipeline, which can easily damage the seal of the foot valve, preventing the water pump from drawing water and affecting the safety of the pipeline.

[0005] 2. The foot valve needs to be installed at the suction port of the pipeline, and the outlet of the foot valve needs to be parallel to the horizontal plane. Therefore, the resistance coefficient of the foot valve is large. Also, because the outlet of the foot valve needs to be parallel to the horizontal plane, debris can easily remain at the seal, which can easily cause poor sealing of the foot valve and prevent the pump from drawing water.

[0006] 3. Once the underwater bottom valve malfunctions, repair or replacement is quite troublesome. For small pools, the water can be pumped out with a submersible pump before repair or replacement. However, for large pools, lakes, or rivers, repair or replacement becomes extremely difficult.

[0007] II. Disadvantages of installing a circulating pump:

[0008] 1. Installing a circulating pump for water intake requires installing a pump, water tank, etc., which is not typically considered in normal use.

[0009] 2. Use a vacuum pump to create a vacuum: Small vacuum pumps cannot create the necessary negative pressure for water intake, while large vacuum pumps are not practical in many places.

[0010] III. Disadvantages of installing surface-mounted foot valves:

[0011] 1. When used in high-lift applications, water hammer may occur in the pipeline, which can easily damage the sealing port of the water-mounted foot valve, causing the water pump to be unable to draw water; and also affecting the safety of the pipeline.

[0012] 2. The above-water foot valve solves the limitations of traditional foot valves, circulation pumps, and vacuum pumps. However, the above-water foot valve must be installed directly above the liquid surface (e.g., ...). Figure 8 As shown in the figure, it is inconvenient to install and maintain.

[0013] 3. The sealing port of the floating foot valve needs to be parallel to the horizontal plane. Therefore, the resistance coefficient of the floating foot valve is large. Also, because the sealing port needs to be parallel to the horizontal plane, debris is easily left at the sealing point, which can easily cause the floating foot valve to not seal well and prevent the pump from drawing water.

[0014] 4. There are technical requirements for connecting the pipeline when installing the water-based foot valve. The pipeline from the outlet of the water-based foot valve to the inlet of the pump must be longer than the distance from the inlet of the water-based foot valve to the liquid surface. If the above conditions are not met, the pump will have difficulty or be unable to draw water. Summary of the Invention

[0015] The present invention aims to provide a pre-pump bottom valve and a system and method for connecting a pump to draw liquid using the same valve. The pre-pump bottom valve, in conjunction with the pump, enables the centrifugal pump to effectively deliver liquid above the liquid surface, thereby solving the limitation of the prior art in the centrifugal pump's ability to draw liquid above the liquid surface.

[0016] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0017] Includes a valve cover, a valve body with a valve cavity, and a pressure plate installed inside the valve cavity;

[0018] The valve body has a bottom valve inlet and a bottom valve outlet, and a shut-off port is provided between the bottom valve inlet and the bottom valve outlet; characterized in that: the pressure plate is driven by a driving mechanism to close or open the shut-off port;

[0019] The valve chamber near the valve cover forms a top inner cavity, and a valve II is installed in the top inner cavity or on the first pipe connected to the bottom valve outlet; the bottom valve inlet is connected to the top inner cavity through a connecting pipe, and a check valve is provided on the connecting pipe, so that fluid can enter the top inner cavity from the bottom valve inlet through the check valve along the connecting pipe.

[0020] Valve I is installed at the outlet of the bottom valve or on the first pipe connected to the outlet of the bottom valve.

[0021] According to embodiments of the present invention, the present invention can be further optimized, and the optimized technical solution is as follows:

[0022] In one preferred embodiment, the connecting pipes are one or more sets.

[0023] In one preferred embodiment, valve III is installed on the connecting pipe at the inlet of the check valve; and / or valve IV is installed on the connecting pipe at the outlet of the check valve.

[0024] In one preferred embodiment, the outlet of valve IV is divided into two branches: one branch is connected to the top cavity through valve V, and the other branch is connected to the bottom valve outlet through a connecting branch pipe.

[0025] In one preferred embodiment, the pressure plate is connected to one end of the piston rod, and the other end of the piston rod contacts a flow-limiting rod extending through the valve cover; the flow-limiting rod is axially movable relative to the valve cover and seals at the contact point, and the flow-limiting rod drives the piston rod to close the shut-off port with the pressure plate.

[0026] In one preferred embodiment, the valve chamber is provided with a piston cylinder, and the piston cylinder contains a piston ring mounted on a piston rod. The outer ring of the piston ring has a sealing ring, and the sealing ring and the piston cylinder are in static contact and sliding contact.

[0027] In one preferred embodiment, the cut-off port is arranged at an angle to the horizontal plane.

[0028] In one preferred embodiment, the piston rod is mounted on a bracket, which is disposed within the valve cavity and fixed to the valve body, and the piston rod can slide vertically relative to the bracket.

[0029] Based on the same inventive concept, the present invention also provides a system for pumping liquid by connecting a pump to a pre-pump bottom valve, wherein the pre-pump bottom valve is located above the liquid surface, the bottom valve inlet of the pre-pump bottom valve is connected to one end of a second pipe, the other end of the second pipe extends into the liquid, and the bottom valve outlet of the pre-pump bottom valve is connected to the inlet end of the pump through a first pipe.

[0030] In one preferred embodiment, a gate valve is provided on the post-pump pipe at the outlet end of the pump.

[0031] Based on the same inventive concept, the present invention also provides a method for pumping liquid using the aforementioned system of connecting a pump to a pump via a pre-pump foot valve, comprising the following steps:

[0032] S1. The pressure plate is closed by the drive mechanism.

[0033] S2. Open the exhaust valves of valve II and pump, and pour liquid into valve I to allow the air in the space above the pressure plate, the first pipe, and the top inner space to be discharged from the exhaust valves of valve II and pump until liquid flows out of the outlet of the exhaust valves of valve II and pump. Then close the exhaust valves of valve II and pump.

[0034] S3. Close valve I to fill the space above the pressure plate, the first pipe, and the top inner space of the pump with liquid;

[0035] S4. When the pump is started, during the process of the liquid being pumped from the space above the pressure plate, the first pipe, and the top inner space to the pump, the air in the second pipe will enter the space above the pressure plate, the first pipe, the pump's inner space, and the top inner space through the check valve and connecting pipe, thereby creating a negative pressure in the second pipe.

[0036] S5. Stop the pump, reopen valve II and the pump's exhaust valve, and pour liquid into valve I to allow the air in the space above the pressure plate, the first pipe, and the top inner space to be discharged from valve II and the pump's exhaust valve until liquid flows out of valve II and the pump's exhaust valve. Then close valve II and the pump's exhaust valve.

[0037] S6. Here, close valve I to fill the space above the pressure plate, the first pipe, and the top inner space of the pump's exhaust valve with liquid, and drive the pressure plate to open the shut-off port through the drive mechanism;

[0038] S7. Restart the pump. The liquid in the liquid pool enters the pump through the shut-off port to achieve liquid delivery.

[0039] In one preferred embodiment, after step S7 and pump shutdown, the pump is started and stopped normally the next time it is used. Therefore, no further operation is required.

[0040] In one preferred embodiment, the pressure plate is connected to one end of the piston rod, and the other end of the piston rod is in contact with a flow-limiting rod extending through the valve cover; the flow-limiting rod is axially movable relative to the valve cover and seals at the contact point, and the flow-limiting rod drives the piston rod to close the pressure plate at the shut-off port; in step S1, the flow-limiting rod is driven to move downward to close the shut-off port at the pressure plate; in step S6, the flow-limiting rod moves upward and no longer presses down on the pressure plate until the pressure plate can be fully opened.

[0041] The liquid in this invention can be water, oil, etc.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] 1. The foot valve before the water pump is installed horizontally with the pump. There are no specified requirements for the length of the first pipe of the pump and the second pipe to the liquid surface. The foot valve before the water pump can be connected and installed close to the pump. Therefore, the foot valve before the pump can be installed in the pump house.

[0044] 2. The foot valve before the water pump can be installed horizontally. The shut-off port of the foot valve before the water pump can be designed to be inclined at a certain angle to the horizontal plane. Therefore, mud and debris are not easy to remain in the shut-off port. This structure can also minimize the flow resistance coefficient of the foot valve before the water pump. With low flow resistance, energy can be saved. Without mud and debris remaining in the shut-off port, the maintenance cycle of the foot valve before the water pump can be extended.

[0045] 3. The foot valve before the water pump can be connected and installed close to the pump, so it can be installed in the pump room, which greatly facilitates the installation and management of the foot valve before the water pump.

[0046] 4. After the foot valve before the water pump is officially put into operation, if water hammer occurs in the pipeline when the pump is stopped, adjusting the opening of valve V can eliminate the water hammer in the pipeline when the pump is stopped. After adjustment, water hammer will not occur in the pipeline when the pump is stopped in subsequent instances. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the bottom valve before the pump on the liquid surface in Embodiment 1 of the present invention;

[0048] Figure 2 This is a schematic diagram of the structure of the bottom valve before the pump on the liquid surface in Embodiment 2 of the present invention (valve III and valve IV are installed);

[0049] Figure 3 This is a schematic diagram of the structure of the pump front bottom valve on the liquid surface in Embodiment 3 of the present invention (piston cylinder, piston ring, sealing ring, valve V, connecting branch pipe, valve III, valve IV are installed);

[0050] Figure 4 This is an assembly diagram of the pump connecting to the liquid in Example 1;

[0051] Figure 5 This is an assembly diagram of the pump connecting to draw liquid in Example 2;

[0052] Figure 6 This is an assembly diagram of the pump connecting to the liquid in Example 3;

[0053] Figure 7 This is an assembly diagram of the pump connecting to the liquid in Example 1 (valve II 15 is installed on the first pipe 1);

[0054] Figure 8 This is an installation diagram of an existing surface-mounted bottom valve.

[0055] In the diagram:

[0056] First Pipeline 1, Bottom Valve Outlet 2, Bottom Valve Inlet 3, Second Pipeline 4, Liquid 5, Pressure Plate 6, Shut-off Port 7, Check Valve 8, Connecting Pipeline 9, Flow Limiting Rod 11, Valve I 12, Upper Space 13, Top Inner Space 14, Valve II 15, Valve III 16, Valve IV 17, Post-Pump Pipeline 18, Support 19, Piston Rod 20, Valve Cover 21, Valve Body 22, Piston Cylinder 23, Piston Ring 24, Sealing Ring 25, Valve V 26, Connecting Branch Pipe 27, Pump 28, Gate Valve 29, Water Bottom Valve 30. Detailed Implementation

[0057] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" used below only indicate that they correspond to the upper, lower, left, and right directions in the accompanying drawings and do not limit the structure.

[0058] like Figure 1 , Figure 2 As shown, a bottom valve for a water pump in this embodiment includes a valve cover 21, a valve body 22, a bracket 19, a pressure plate 6, a piston rod 20, a flow-limiting rod 11, a shut-off port 7, a check valve 8, and a connecting pipe 9. The valve body 22 has a bottom valve inlet 3 and a bottom valve outlet 2, with a shut-off port 7 located between them. The bracket 19 is fixedly mounted on the valve body 22, parallel to the shut-off port 7. The piston rod 20 is vertically fixed and sealed to the pressure plate 6, passing vertically through the bracket 19, and can slide vertically within the bracket 19. The flow-limiting rod 11 is mounted on the valve cover 21, and the contact point between the flow-limiting rod 11 and the valve cover 21 is sealed. The flow-limiting rod 11 can move axially relative to the valve cover 21, and driving the flow-limiting rod 11 to move downwards to contact the piston rod 20 and press the pressure plate 6. The valve cover 21 and the valve body 22 are sealed together.

[0059] The foot valve inlet 3 is connected to the foot valve outlet 2 via check valve 8 and connecting pipe 9. This allows fluid to flow from the foot valve inlet 3 through check valve 8 and connecting pipe 9 to the foot valve outlet 2, preventing the fluid from flowing back from the foot valve outlet 2 to the foot valve inlet 3. The installed check valve 8 and connecting pipe 9 can be one or more sets.

[0060] like Figure 1-7 As shown, valve I12 is installed at the bottom valve outlet 2 or on the first pipe 1 of pump 28.

[0061] Install valve II15 at the top of the bottom valve of the water pump, in the cavity 14, or on the first pipe of pump 28.

[0062] In these embodiments, a valve III16 is installed at the inlet of the check valve 8, and a valve IV17 is installed on the connecting pipe 9 for use when maintaining the check valve 8; after the pump 28 is normally delivering liquid, valves III16 and IV17 may be closed or not closed.

[0063] like Figure 3As shown, a piston cylinder 23 is installed between the valve cover 21 and the valve body 22. The piston cylinder 23 is spaced parallel to the stop port 7. The piston cylinder 23 contains a piston ring 24. The outer ring of the piston ring 24 has a sealing ring 25. The sealing ring 25 and the piston cylinder 24 are in static contact and sliding contact. The piston ring 24 is installed on the piston rod 20. The piston ring 24 and the piston rod 20 are vertically fixed and sealed. The valve cover 21, valve body 22 and piston cylinder 23 are fixedly sealed. A valve V 26 is installed at the top of the bottom valve of the water pump, and the connecting branch pipe 27 is connected to the bottom valve outlet 2.

[0064] After the foot valve of the water pump is put into operation, if water hammer occurs in the pipeline when the pump is stopped, adjusting the opening of valve V26 can eliminate the water hammer in the pipeline when the pump is stopped; after adjustment, no water hammer will occur in the pipeline when the pump is stopped in the future.

[0065] like Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown, due to the routing of the post-pump pipeline 18 at the pump outlet, if the liquid entering through valve I12 is insufficient, the gate valve 29 at the pump outlet must be closed, and then slowly opened again when starting the pump. A check valve may not be installed at the outlet of pump 28.

[0066] When it is inconvenient to install valve I12 at the outlet 2 of the foot valve, valve I12 can be installed on the first pipe 1 of pump 28. When it is inconvenient to install valve II15 at the top inner cavity 14 of the foot valve before the water pump, valve II15 can be installed on the first pipe 1 of pump 28.

[0067] The first pipe 1 of pump 28 is sealed to the outlet 2 of the bottom valve, and the inlet 3 of the bottom valve is sealed to the second pipe 4 into the liquid 5.

[0068] The flow-limiting rod moves downward to contact the piston rod 20, pressing down the pressure plate 6. The exhaust valves of valve II 15 and pump 28 are opened, and liquid is poured in through valve I 12, causing the air in the space above the pressure plate 6, the first pipe 1, and the top inner space 14 to be discharged through the exhaust valves of valve II 15 and pump 28 until liquid comes out of the exhaust valves of valve II 15 and pump 28. Then, the exhaust valves of valve II 15 and pump 28 are closed, and then valve I 12 is closed again, so that the space above the pressure plate 6, the first pipe 1, and the top inner space 14 are filled with liquid through the exhaust valve of pump 28.

[0069] When the pump is started, the liquid in the space above the pressure plate 6, the first pipe 1, the top inner space 14 and the pump is pumped away. During the process of the liquid being pumped away, the air in the pipe that seals the bottom valve inlet 3 to the second pipe 4 to the liquid 5 will enter the space above the pressure plate 6, the first pipe 1 and the inner space of the pump 28, and the top inner space 14 through the check valve 8 and the connecting pipe 9, so that a negative pressure is formed in the second pipe 4 that seals the bottom valve inlet 3 to the liquid 5. After stopping the pump, open the exhaust valves of valve II15 and pump 28, and pour liquid into valve I12 to allow the air in the space above the pressure plate 6, the first pipe 1, and the top inner space 14 to be discharged from the exhaust valves of valve II15 and pump 28 until liquid comes out of the exhaust valves of valve II15 and pump 28. Then close the exhaust valves of valve II15 and pump 28, and then close valve I12 to fill the space above the pressure plate 6, the first pipe 1, and the top inner space 14 with liquid. Drive the flow limiting rod 11 to stop pressing the pressure plate 6 of the bottom valve on the water surface, and return the flow limiting rod 11 to a position that allows the pressure plate 6 to be fully opened.

[0070] When the pump is restarted, the liquid 5 in the liquid pool, pressurized by atmospheric pressure, can enter the centrifugal chamber of pump 28 through the shut-off port 7 of the bottom valve before the water pump, thus realizing the liquid transfer. After stopping the pump, it can be started and stopped normally the next time it is needed. No other operations are required.

[0071] Working principle: After liquid is injected through valve I12 to fill the space 13 above the pressure plate 6 of the bottom valve of the water pump 28, the first pipeline 1, and the top inner space 14 of the bottom valve of the water pump, the working principle is explained as follows when the pump is started for the first time if the bottom valve of the water pump is not equipped with the flow limiting rod 11 and the check valve 8:

[0072] When the pump is started for the first time, as the liquid is pumped away from the space 13 above the pressure plate 6 of the bottom valve of the water pump, the first pipe 1, the top inner space 14 of the bottom valve of the water pump, and the pump itself, air in the pipe from the sealing connection between the bottom valve inlet 3 and the second pipe 4 to the liquid 5 will enter the pump through the shut-off port 7 into the space 13 above the pressure plate 6, the first pipe 1, the top inner space 14 of the bottom valve of the water pump, and the pump itself. After the liquid in the space 13 above the pressure plate 6 of the bottom valve of the water pump, the first pipe 1, the top inner space 14 of the bottom valve of the water pump, and the pump itself is pumped away, the pump is stopped. At this time, the pressure... The reset of plate 6 takes a certain amount of time. There is little liquid around the stop port 7 and the perimeter is long, so the sealing performance of pressure plate 6 will be poor. The air in the space 13 above pressure plate 6 of the bottom valve of the water pump, the first pipe 1, the top inner space 14 of the bottom valve of the water pump and the pump will flow back into the second pipe 4. After that, every time the pump is stopped and restarted according to the procedure, the air flowing back in the second pipe 4 will always cause the negative pressure value formed to be unable to push pressure plate 6 to the required opening. As a result, the negative pressure value generated in the second pipe 4 cannot reach the bottom valve outlet 2 to deliver liquid 5, so the pump cannot deliver liquid.

[0073] It should be noted that to solve the problem of less air flowing back into the second pipe 4, the first solution is to increase the weight of the pressure plate 6 or use a spring to speed up the reset of the pressure plate 6 and increase the pressure applied by the pressure plate 6 to the shut-off port 7, thereby enhancing the sealing of the pressure plate 6 and reducing the amount of air flowing back into the second pipe 4. However, after the weight of the pressure plate 6 is increased, the relative opening of the pressure plate 6 will create a negative pressure value in the second pipe 4 that is insufficient to push open the pressure plate 6 to deliver liquid to the bottom valve outlet 2, causing the outlet 2 of the bottom valve before the water pump to always remain open. One solution is to adjust the weight of the pressure plate 6 to a suitable level. This reduces air backflow into the second pipe 4, ensuring the negative pressure created by the small amount of air flowing back into the second pipe 4 is sufficient to push the pressure plate 6 open. Additionally, the length of the first pipe 1 should be longer than the length of the second pipe 4 to the liquid surface. This design minimizes air backflow into the second pipe 4, allowing the negative pressure to push the pressure plate 6 open and thus enabling liquid delivery. Figure 8 (As shown).

[0074] The first method, increasing the weight of the pressure plate 6, solves the problem of less air flowing back into the second pipe 4. However, this results in the negative pressure generated in the second pipe 4 being insufficient to push the pressure plate 6 open and deliver liquid to the bottom valve outlet 2. The second method, reducing the weight of the pressure plate 6, aims to reduce the amount of air flowing back into the second pipe 4 and ensure that the negative pressure generated by the small amount of air flowing back into the second pipe 4 can push the pressure plate 6 open. However, this requires the length of the first pipe 1 to be longer than the length of the second pipe 4 to the liquid surface. If the first pipe 1 is to be as short as possible, the pressure plate 6 must meet the required thickness for the operating conditions, and it must also have fast backflow prevention and good sealing. This presents a dilemma, leading to many unsolvable problems in the design, manufacturing, and installation of the bottom valve. Therefore, a good solution has not yet been found to enable the centrifugal pump to deliver liquid above the liquid surface.

[0075] The following example, using the method of connecting the front foot valve of a water pump to the pump to draw liquid, illustrates its working principle:

[0076] The drive flow limiting rod moves downward to press down the pressure plate 6, and liquid is poured in from valve I12 to fill the space 13 above the pressure plate 6 of the water pump 28's exhaust valve, the first pipeline 1, and the top inner space 14 of the water pump's front foot valve with liquid. When the pump is started for the first time, as the liquid in the space 13 above the pressure plate 6 of the water pump's front foot valve, the first pipeline 1, and the top inner space 14 of the water pump's front foot valve is pumped away, during the process of the liquid being pumped away, the space in the pipe connecting the bottom valve inlet 3 to the second pipeline 4 and the liquid 5 is sealed. Air can only enter the pump through the check valve 8, passing through the space 13 above the pressure plate 6, the first pipe 1, the top inner space 14 of the bottom valve of the water pump, and finally into the pump. Once the liquid in the pump has been transported away through these channels, the pump stops. At this point, the pressure plate 6 is pressed down by the flow-limiting rod 11, preventing the air in the pump from flowing back through the shut-off port 7 into the second pipe 4. If the liquid needs to flow back into the second pipe 4, it can only do so through the check valve 8. Because the check valve 8 has a small diameter, its sealing performance is good, and the return time is short. Therefore, very little air flows back into the second pipe 4. When the liquid is pumped away, the pump 28 has a large suction force, and the pressure plate of the check valve 8 is light. The air entering the outlet 2 of the foot valve of the water pump through the check valve 8 is fast. The air entering the outlet 2 of the foot valve is sufficient to fill the space 13 above the pressure plate 6 of the water pump, the top inner space 14, and the first pipe 1. The liquid can be transported to the centrifuge chamber of pump 28, and the liquid can be pumped out. The space above the liquid pressure plate 6, the space above the liquid pressure plate 6, the space above the liquid pressure plate 13, the space above the liquid pressure plate 14, and the space of the first pipe 1 will be occupied by the air coming in from the second pipe 4. After the air in the second pipe 4 becomes rarefied, the pressure plate of the check valve 8 can allow the rarefied air in the second pipe 4 to enter the outlet 2 of the bottom valve of the water pump to the maximum extent. When the negative pressure value formed in the second pipe 4 is restored to normal and the pump is started, it is sufficient to push the piston 6 to deliver the liquid 5 to the bottom valve outlet 2.

[0077] Before restarting the pump: Open the exhaust valves of valve II15 and pump 28, and pour liquid into valve I12 to allow the air in the space above the pressure plate 6, the first pipe 1, and the top inner space 14 to be discharged from the exhaust valves of valve II15 and pump 28 until liquid comes out of the exhaust valves of valve II15 and pump 28. Then close the exhaust valves of valve II15 and pump 28, and then close valve I12 to fill the space above the pressure plate 6, the first pipe 1, and the top inner space 14 with liquid. Drive the flow limiting rod 11 to stop pressing the pressure plate 6 of the bottom valve of the water pump, and return the flow limiting rod 11 to a position that allows the pressure plate 6 of the bottom valve of the water pump to be fully open.

[0078] After the space 13 above the pressure plate 6 of the bottom valve of the water pump 28, the first pipe 1, and the top inner space 14 of the bottom valve of the water pump are filled with liquid, the flow limiting rod 11 is finally driven to stop pressing the pressure plate 6 of the bottom valve of the water pump. This is to ensure that air will not flow back from the stop port 7 into the second pipe 4.

[0079] A check valve may not be installed at the outlet of pump 28. Without a check valve, before restarting the pump, open valve II 15 and the vent valve of pump 28 to vent until liquid is discharged. Then close valve II 15 and the vent valve of pump 28. Drive the flow limiting rod 11 to stop pressing the pressure plate 6 of the bottom valve of the water pump. Move the flow limiting rod 11 back to the position that allows the pressure plate 6 of the bottom valve of the water pump to be fully open.

[0080] When the pump is restarted, the liquid 5 in the liquid pool is pressurized by atmospheric pressure and can push open the pressure plate 6 and enter the bottom valve outlet 2 through the shut-off port 7, thus realizing the liquid transportation. After confirming that the pump is normally transporting liquid, the pump is stopped. The next time it is needed, the pump can be started and stopped normally without any other operations.

[0081] The method of connecting the foot valve before the water pump in this embodiment to the pump allows the centrifugal pump to be positioned above the liquid surface. The foot valve before the water pump can be installed horizontally, connected close to the pump, or installed in the pump house, and can effectively transport liquid. This method allows the design, manufacturing, and installation of the foot valve before the water pump to meet the requirements of the working conditions to the maximum extent, minimizes the flow resistance coefficient of the foot valve before the water pump, provides the pump with the maximum flow rate, and achieves energy savings. The foot valve before the water pump can slowly close to check back, eliminate water hammer in the pipeline, and ensure pipeline safety. Due to its convenient installation and simple operation, the foot valve before the water pump can be used in a wider range of applications.

[0082] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present embodiments by those skilled in the art will fall within the scope defined by the appended claims.

Claims

1. A method for pumping liquid using a system connected to a pump via a pre-pump foot valve, the pre-pump foot valve comprising a valve cover (21), a valve body (22) having a valve cavity, and a pressure plate (6) installed within the valve cavity; the valve body (22) having a foot valve inlet (3) and a foot valve outlet (2), with a shut-off port (7) provided between the foot valve inlet (3) and the foot valve outlet (2); characterized in that: The pressure plate (6) is driven by the drive mechanism to close or open the stop port (7); The valve chamber near the valve cover (21) forms a top inner cavity (14), and a valve II (15) is installed at the top inner cavity (14) or on the first pipe (1) connected to the bottom valve outlet (2); the bottom valve inlet (3) is connected to the top inner cavity (14) through a connecting pipe (9), and a check valve (8) is provided on the connecting pipe (9), so that fluid can enter the top inner cavity (14) from the bottom valve inlet (3) through the check valve (8) along the connecting pipe; The valve I (12) is installed at the location of the bottom valve outlet (2) or on the first pipe (1) connected to the bottom valve outlet (2). The bottom valve before the pump is set above the liquid surface. The bottom valve inlet (3) of the bottom valve before the pump is connected to one end of the second pipe (4). The other end of the second pipe (4) extends into the liquid (5). The bottom valve outlet (2) of the bottom valve before the pump is connected to the inlet end of the pump (28) through the first pipe (1). The method for pumping liquid includes the following steps: S1. Drive the pressure plate (6) to close the shut-off port through the drive mechanism; S2. Open the exhaust valves of valve II (15) and pump, and pour liquid into valve I (12) so that the air in the space above the pressure plate (6) (13), the first pipe (1), and the top inner space (14) is discharged from the exhaust valves of valve II (15) and pump (28) until liquid flows out from the outlet of the exhaust valves of valve II (15) and pump (28). Then close the exhaust valves of valve II (15) and pump (28). S3. Close valve I (12) to fill the space (13) above the pressure plate (6), the first pipe (1), and the top inner space (14) of the pump (28) with liquid; S4. When the pump (28) is started, during the process of the liquid being transported from the space above the pressure plate (6) (13), the first pipe (1), the top inner space (14) to the pump (28), the air in the second pipe (4) will enter the space above the pressure plate (6) (13), the first pipe (1), the inner space of the pump (28), and the top inner space (14) through the check valve (8) and the connecting pipe (9), thereby forming a negative pressure in the second pipe (4); S5. Stop pump (28), open valve II (15) and pump (28) exhaust valve again, pour liquid into valve I (12) so that the air in the space above the pressure plate (6) (13), the first pipe (1) and the top inner space (14) is discharged from the exhaust valve of valve II (15) and pump (28) until liquid flows out of the exhaust valve of valve II (15) and pump (28), then close the exhaust valve of valve II (15) and pump (28); S6. Here, close valve I (12) to fill the space (13) above the pressure plate (6), the first pipe (1), and the top inner space (14) of the pump (28) with liquid, and drive the pressure plate (6) to open the shut-off port through the drive mechanism; S7. Start the pump (28) again. The liquid (5) in the liquid pool enters the pump (28) through the shut-off port (7) to realize the liquid transportation.

2. The method for pumping liquid according to claim 1, characterized in that, The connecting pipes (9) are one or more sets.

3. The method for pumping liquid according to claim 1, characterized in that, A valve III (16) is installed on the connecting pipe (9) at the inlet of the check valve (8); and / or a valve IV (17) is installed on the connecting pipe (9) at the outlet of the check valve (8).

4. The method for pumping liquid according to claim 3, characterized in that, The outlet of valve IV (17) is divided into two branches. One branch is connected to the top inner cavity (14) through valve V (26), and the other branch is connected to the bottom valve outlet (2) through connecting branch pipe (27).

5. The method for pumping liquid according to any one of claims 1-4, characterized in that, The pressure plate is connected to one end of the piston rod (20), and the other end of the piston rod (20) is in contact with the flow-limiting rod (11) extending through the valve cover (21); the flow-limiting rod (11) can move axially relative to the valve cover (21) and seal at the contact point, and the flow-limiting rod (11) drives the piston rod (20) to close the stop port (7) with the pressure plate (6).

6. The method for pumping liquid according to claim 5, characterized in that, The valve chamber is provided with a piston cylinder (23), and the piston cylinder (23) contains a piston ring (24) mounted on the piston rod (20). The outer ring of the piston ring (24) has a sealing ring (25), and the sealing ring (25) and the piston cylinder (24) are in static contact and sliding contact.

7. The method for pumping liquid according to claim 6, characterized in that, The piston rod (20) is mounted on the bracket (19), which is located in the valve cavity and fixed on the valve body (22). The piston rod (20) can slide up and down relative to the bracket (19).

8. The method for pumping liquid according to any one of claims 1-4, characterized in that, The cut-off port is arranged at an angle to the horizontal plane.

9. The method for pumping liquid according to any one of claims 1-4, characterized in that, A gate valve (29) is provided on the post-pump pipe (18) at the outlet end of the pump (28).

10. The method for pumping liquid according to any one of claims 1-4, characterized in that, After step S7, after stopping the pump (28), the pump will be started and stopped normally the next time it is used.

11. The method for pumping liquid according to any one of claims 1-4, characterized in that, The pressure plate is connected to one end of the piston rod (20), and the other end of the piston rod (20) is in contact with the flow-limiting rod (11) extending through the valve cover (21); the flow-limiting rod (11) can move axially relative to the valve cover (21) and seal at the contact point, and the flow-limiting rod (11) drives the piston rod (20) to close the stop port (7) with the pressure plate (6). In step S1, the drive flow limiting rod (11) moves downward to close the stop port with the pressure plate (6); In step S6, the flow-limiting rod (11) moves upward and no longer presses down on the pressure plate (6) until the pressure plate (6) can be fully opened.

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