Integrated double check valve

Abstract

The invention relates to the technical field of double check valves, in particular to an integrated double check valve which comprises a series connection pipe and a connecting sleeve, a plurality of fixing plates are connected to the inner wall of the series connection pipe, the connecting sleeve is connected to the bottom ends of the fixing plates, a partition plate is connected into the connecting sleeve, and a front reset spring and a rear reset spring are installed on the front side and the rear side of the partition plate respectively. According to the invention, the rear diaphragm is pushed to extrude the front and rear reset springs through the thrust of water flow during downstream, so that the impact force during downstream is buffered, meanwhile, the ejector rod is driven to be connected with the fixing assembly, the fixation of the front push rod is relieved, and at the moment, the front and rear reset springs push the front push rod to separate the front diaphragm from the front sealing edge; the rear membrane is attached to the rear sealing edge under the thrust of the front reset spring and the rear reset spring, and the front membrane is attached to the front sealing edge under the thrust of water flow in the countercurrent process and extrudes the front reset spring and the rear reset spring to buffer a water hammer in the countercurrent process.

Description

Technical Field

[0001] The invention relates to the technical field of double check valves, in particular to an integrated double check valve. Background Art

[0002] A double check valve is a check valve composed of two check valves connected in series. When a double check valve is in use, if one of the valves cannot be closed due to blockage, the other valve will still work. Secondly, closing one valve will reduce the pressure difference on both sides of the other valve, thereby achieving a more reliable seal and avoiding minor leaks. Therefore, it is used in drainage systems, fire protection systems and drinking water systems.

[0003] For example, in order to prevent the reverse flow of water in the pipeline in the mine drainage system, which may cause the pump unit to reverse and escape and cause damage to the unit, a check valve is installed in the pipeline to prevent the water in the pipeline from flowing back. However, when the check valve closes quickly to seal the pipeline, the impact of the reverse flow of water on the check valve diaphragm will cause a large water hammer pressure increase, resulting in the rupture of the pipeline due to local overpressure. In the prior art, a slow-closing check valve is used to reduce water hammer. The slow-closing check valve reduces the water hammer during reverse flow by slowly closing the diaphragm. However, during the slow closing process of the slow-closing check valve, part of the water will still flow back. In addition, the water discharged from the mine contains more sediment. The reverse flow of water will form a water column with sediment. During reverse flow, not only the reverse flow of water column will impact the pump unit, but also the sediment particles in the water flow will impact the pump unit, causing damage to the unit.

[0004] To this end, an integrated double check valve is proposed. Summary of the invention

[0005] The object of the present invention is to provide an integrated double check valve. In order to solve the large water hammer phenomenon when the check valve is quickly closed in a drainage system, the rear diaphragm of the double check valve can be opened slowly and closed quickly, and the front diaphragm can be opened quickly and closed slowly during operation.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An integrated double check valve comprises a series pipe and a connecting sleeve, wherein the inner wall of the series pipe is connected to a plurality of fixed plates, the connecting sleeve is connected to the bottom end of the fixed plate, the connecting sleeve is connected to a partition plate inside, a front return spring and a rear return spring are respectively installed on the front and rear sides of the partition plate, a rear push rod is arranged on the rear side of the partition plate, a rear diaphragm is connected to the rear end of the rear push rod, a piston plate is connected to the front end of the rear push rod, the front side of the piston plate is connected to the rear return spring, the front side of the partition plate is connected to the front push rod, and the rear end of the front push rod is connected to the front return spring. The front push rod is connected with a spring, the front side of the front push rod is connected with a front diaphragm, the inner wall of the series tube is connected with a rear sealing edge and a front sealing edge, the rear sealing edge is in contact with the rear side of the rear diaphragm, the front sealing edge is in contact with the rear side of the front diaphragm, the inner wall of the front push rod is connected with a fixing assembly, and the front side of the piston plate is connected with a push rod. When the front diaphragm is in contact with the front sealing edge, the front push rod compresses the front return spring to store energy, and fixes the front push rod through the fixing assembly. When the rear diaphragm is separated from the rear sealing edge, the push rod moves forward and releases the fixation of the fixing assembly.

[0008] In the above scheme, when the water flows downstream, the rear diaphragm moves the rear push rod under the thrust of the water flow, and squeezes the rear return spring on the rear side of the partition, thereby buffering the impact force when the water flow pushes the rear diaphragm. At the same time, it will drive the top rod to connect with the fixing assembly, so that the fixing assembly releases the fixation of the front push rod, and the front push rod moves to the front side under the thrust of the front return spring, and drives the front diaphragm to separate from the front sealing edge. When the water flows upstream, the rear diaphragm quickly fits with the rear sealing edge under the thrust of the rear return spring, thereby achieving sealing, and the front diaphragm is pushed to fit with the front sealing edge by the reverse water flow. When the reverse water flow pushes the front diaphragm, the front return spring will be compressed, thereby buffering the water hammer during the reverse flow.

[0009] Preferably, the rear sealing edge includes a base layer and a rubber membrane, the base layer is connected to the inner wall of the series tube and is located on the rear side of the rear diaphragm, the rubber membrane is connected to the outer wall of the base layer, there is a cavity between the rubber membrane and the base layer, a connecting hole is opened on the inner wall of the fixed plate, one end of the connecting hole is connected to the connecting sleeve, and the connecting point is located on the rear side of the piston plate, and the other end of the connecting hole is connected to the cavity.

[0010] In the above scheme, when the water flows downstream, the gas in the cavity enters the interior of the connecting sleeve, increasing the inner circle diameter of the rear sealing edge, thereby increasing the diameter of the water flow; when the water flows upstream, the gas inside the connecting sleeve enters the cavity, causing the rubber membrane to expand, thereby buffering the impact force when the rear diaphragm and the rubber membrane are fitted together.

[0011] Preferably, a mounting groove is opened on the front side of the rear diaphragm, an inner wall of the mounting groove is connected to an arc-shaped top block, and a sealing film is connected to the front side of the rear diaphragm, and the sealing film covers the mounting groove and the arc-shaped top block.

[0012] In the above scheme, when the rear sealing membrane is in contact with the rear sealing edge, the sealing membrane on the rear side of the rear diaphragm forms a concave surface to increase the thrust when it just contacts the water flow. When the rear diaphragm is separated from the rear sealing edge, the rear side is an arc-shaped convex surface to reduce the head loss of the water flow during flow.

[0013] Preferably, the fixing assembly includes a trapezoidal block, a connecting rod, and a telescopic rod. A groove is provided on the inner wall of the front push rod, and sliding grooves are provided on both sides of the outer wall of the front push rod. The sliding grooves are connected to the grooves, and the trapezoidal block is connected to the inside of the sliding groove. A baffle is connected to the inner wall of the series tube, and the baffle is located at the rear side of the trapezoidal block when the front diaphragm is separated from the front sealing edge. The connecting rod is hinged to the right-angled side of the trapezoidal block, and the telescopic rod is connected to the front side of the inner wall of the groove. The rear end of the telescopic rod is hinged to the connecting rod, and a compression spring is provided on the outer wall of the telescopic rod. The front end of the compression spring is connected to the front side of the inner wall of the groove, and the rear end is connected to the telescopic rod. The telescopic rod has the same axis as the push rod and cooperates with the rear end of the push rod.

[0014] In the above scheme, when the top rod pushes the telescopic rod to shorten, the telescopic rod pulls the connecting rod to retract the trapezoidal block into the slide groove, so that the trapezoidal block is separated from the baffle, thereby releasing the fixation of the front push rod. When the water flows backward, the front push rod is pushed to move by pushing the front diaphragm, so that the trapezoidal block moves to the back side of the baffle and engages with the baffle to fix the front push rod.

[0015] Preferably, a buffer hole is opened inside the tube wall of the series tube, and both ends are connected to the inside of the series tube, one end of the buffer hole is located between the front and rear fixed plates on the inner wall of the series tube, and the other end is located on the front side of the front sealing edge, the inner wall of the buffer hole is connected to a slider, one end of the slider is connected to a fixing rod, and the fixing rod is connected to the front diaphragm.

[0016] In the above scheme, when the water flows backward, part of the water flows into the buffer hole, pushing the slider to move toward the rear end of the buffer hole, thereby further reducing the water hammer.

[0017] Preferably, a reflux hole is opened inside the tube wall of the series tube, one end of the reflux hole is connected to a rotating cover plate, the rotating cover plate is arc-shaped, the cross-section of the rotating cover plate is set to be arc-shaped, and is hinged to the inner wall of the series tube near the rear diaphragm side, the rotating cover plate is opened with an arc groove near the front diaphragm side, and the other end of the reflux hole is connected to a duckbill tube.

[0018] In the above scheme, when the water flow inside the series pipe flows backward, the rotating cover is opened to allow the reversed water to enter the reflux hole, and finally the water flows out from the duckbill tube, directing the water flow to the front side of the front diaphragm to form convection with the reversed water flow, thereby further reducing water hammer.

[0019] Preferably, the front sealing edge forms a circle around the inner wall of the series pipe, and the diameter of the series pipe gradually decreases from the back to the front, and the minimum diameter is the same as the inner diameter of the front sealing edge.

[0020] In the above scheme, the inner diameter of the series pipes is reduced from the back to the front, thereby reducing the water pressure inside the series pipes during backflow, thereby protecting the series pipes.

[0021] Preferably, a plurality of fan blades are connected to the top of the rear diaphragm, the cross-section of the fan blades is set to be L-shaped, and the fan blades are connected to a movable plate in a clockwise direction.

[0022] In the above scheme, the movable plate is connected to the fan blades through a torsion spring and has an angle with the fan blades. When the water flows downstream, it passes through the fan blades to drive the rear diaphragm to rotate, thereby cleaning the mud and sand on the inner wall of the series tube. When the water flows upstream, the water flow impacts the movable plate, causing the movable plate to deflect, thereby reducing the impact on the front side of the rear diaphragm during upstream flow.

[0023] Preferably, the front side of the front diaphragm is configured to be arc-shaped, an annular groove is provided on the front side of the front diaphragm, a moving block is connected to the inside of the annular groove, and the moving block is connected to the front push rod.

[0024] In the above scheme, when the front diaphragm is separated from the front sealing edge, the moving block and the front side of the front diaphragm form a concave surface, thereby increasing the thrust during backflow. When the front diaphragm is in contact with the front rotating cover plate, the moving block and the front side of the front diaphragm form an arc during movement, thereby reducing the backflow thrust after sealing.

[0025] Preferably, the cross section of the base layer is set to be a right-angled trapezoid, and the rear side is a hypotenuse.

[0026] In the above scheme, the rear side is set as a beveled edge, so that the impact on the rear sealing edge is reduced when flowing downstream, and the accumulation of mud and sand on the rear side of the rear sealing edge is also avoided.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. By installing a front return spring and a rear return spring on the front and rear sides of the partition respectively, when the water flows downstream, the rear diaphragm is pushed to squeeze the rear return spring on the rear side of the partition, thereby buffering the impact force during downstream flow, and at the same time, it will drive the push rod to connect with the fixing assembly, so that the fixing assembly releases the fixation of the front push rod, and the front push rod drives the front diaphragm and the front sealing edge to separate quickly under the thrust of the front return spring, so that the front diaphragm is not pushed to open by the impact force of the water during downstream flow, so that the head loss of the water flow during downstream flow is reduced, and when the water flows reversely, the rear diaphragm quickly fits with the rear sealing edge under the thrust of the rear return spring to perform sealing, and the front diaphragm fits with the front sealing edge under the thrust of the water flow during reverse flow, and presses the front return spring on the front side of the partition, thereby buffering the water hammer during reverse flow.

[0029] 2. The rear sealing edge is formed by the base layer and the rubber membrane. When the water flows downstream, the piston plate moves forward and draws the gas in the cavity into the connecting sleeve, so that the inner circle diameter of the rear sealing edge increases, thereby increasing the diameter of the water flow. When the water flows upstream, the piston plate moves backward and pushes the gas inside the connecting sleeve into the cavity, causing the rubber membrane to expand, buffering the impact force when the rear diaphragm and the rubber membrane are attached, reducing the damage to the rear diaphragm during impact.

[0030] 3. By setting the installation groove, the arc-shaped top block and the sealing film, when the rear sealing film is fitted with the rear sealing edge, the arc-shaped top block is squeezed into the groove, so that the sealing film on the rear side of the rear diaphragm forms a concave surface, thereby increasing the thrust when the rear diaphragm just contacts the water flow, making it easier for the water flow to push the rear diaphragm open and pass quickly. When the rear diaphragm is separated from the rear sealing edge, the arc-shaped top block pushes the sealing film out under the push of the internal gas, so that the rear side of the rear diaphragm is an arc-shaped convex surface, reducing the head loss when the water flow is smooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 It is a schematic diagram of the cross-sectional structure of the present invention;

[0033] Figure 3 It is a schematic diagram of the rear diaphragm structure of the present invention;

[0034] Figure 4 For the present invention Figure 2 A schematic diagram of the enlarged structure of part A;

[0035] Figure 5 For the present invention Figure 2 A schematic diagram of the enlarged structure of part B;

[0036] Figure 6 For the present invention Figure 2 A schematic diagram of the enlarged structure of the middle C part;

[0037] Figure 7 It is a schematic diagram of the fan blade structure of the present invention;

[0038] Figure 8 It is a schematic diagram of the closed state structure of the present invention.

[0039] In the figure: 1, series pipe; 101, fixed plate; 102, rear sealing edge; 1021, base layer; 1022, rubber membrane; 1023, cavity; 103, front sealing edge; 104, connecting hole; 105, baffle; 106, buffer hole; 107, reflux hole; 2, connecting sleeve; 3, partition; 4, rear return spring; 5, front return spring; 6, rear push rod; 601, piston plate; 602, push rod; 7, rear diaphragm; 701, mounting groove; 7 02, arc-shaped top block; 703, sealing membrane; 8, front push rod; 801, groove; 802, slide groove; 9, front diaphragm; 901, annular groove; 902, moving block; 10, fixed assembly; 1001, trapezoidal block; 1002, connecting rod; 1003, telescopic rod; 1004, compression spring; 11, slider; 12, fixed rod; 13, rotating cover plate; 1301, arc-shaped groove; 14, duckbill tube; 15, fan blade; 1501, movable plate. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figures 1 to 8 The present invention provides an integrated double check valve, and the technical solution is as follows:

[0042] An integrated double check valve, referring to Figure 1 and Figure 2 , including a series tube 1 and a connecting sleeve 2, the inner wall of the series tube 1 is connected to a plurality of fixed plates 101, the connecting sleeve 2 is connected to the bottom end of the fixed plate 101, the connecting sleeve 2 is connected to a partition 3 inside, the front and rear sides of the partition 3 are respectively installed with a front return spring 5 and a rear return spring 4, the two thrust directions of the front and rear return springs 4 are opposite, the rear side of the partition 3 is provided with a rear push rod 6, the rear end of the rear push rod 6 is connected to a rear diaphragm 7, the front end of the rear push rod 6 is connected to a piston plate 601, the front side of the piston plate 601 is connected to the rear return spring 4, the rear return spring 4 on the rear side of the partition 3 pushes the piston plate 601 to make the rear diaphragm 7 fit with the rear sealing edge 102, the right side of the partition 3 is connected to a front push rod 8, the rear end of the front push rod 8 is connected to the front return spring 5, the front side of the front push rod 8 is connected to a front diaphragm 9, the front diaphragm 9 is separated from the front sealing edge 103 by the front return spring 5 on the front side of the partition 3.

[0043] The inner wall of the series pipe 1 is connected with a rear sealing edge 102 and a front sealing edge 103, and the rear sealing edge 102 is fitted with the rear side of the rear diaphragm 7. When the water flows downstream, the rear diaphragm 7 is separated from the rear sealing edge 102 under the thrust of the water flow, thereby opening the channel of the rear sealing edge 102, and the water flow will also push the rear push rod 6 to move when pushing the rear diaphragm 7 to move. When the rear push rod 6 moves, it will squeeze the rear return spring 4 on the rear side of the partition 3, thereby buffering the impact force when the water flow pushes the rear diaphragm 7. When the water flows countercurrently, the rear diaphragm 7 quickly fits with the rear sealing edge 102 under the thrust of the rear return spring 4, thereby achieving sealing. The front sealing edge 103 is fitted with the rear side of the front diaphragm 9, the inner wall of the front push rod 8 is connected with a fixing assembly 10, and the front side of the piston plate 601 is connected with a push rod 602. When the sheet 9 is in contact with the front sealing edge 103, the front push rod 8 compresses the front return spring 5 to store energy, and fixes the front push rod 8 through the fixing assembly 10. When the rear diaphragm 7 is separated from the rear sealing edge 102, the top rod 602 moves forward and releases the fixation of the fixing assembly 10. When the water flows downstream, the rear push rod 6 moves and drives the top rod 602 to connect with the fixing assembly 10, so that the fixing assembly 10 releases the fixation of the front push rod 8. At this time, the front push rod 8 moves forward under the thrust of the front return spring 5 on the front side of the partition 3, driving the front diaphragm 9 to separate from the front sealing edge 103. When the water flows backward, the front diaphragm 9 is pushed by the reverse water flow to fit the front sealing edge 103. When the reverse water flow pushes the front diaphragm 9, the front return spring 5 is compressed by the front push rod 8, thereby buffering the water hammer during the reverse flow, and at the same time the fixing assembly 10 fixes the front push rod 8.

[0044] As an embodiment of the present invention, refer to Figure 3 and Figure 8 The rear sealing edge 102 includes a base layer 1021 and a rubber film 1022. The base layer 1021 is connected to the inner wall of the series pipe 1 and is located at the rear side of the rear diaphragm 7. The rubber film 1022 is connected to the outer wall of the base layer 1021. There is a cavity 1023 between the rubber film 1022 and the base layer 1021. Initially, the rear diaphragm 7 and the rubber film 1022 are in contact with each other, and the cavity 1023 is filled with gas. A connecting hole 104 is opened on the inner wall of the fixing plate 101. One end of the connecting hole 104 is connected to the connecting sleeve 2, and the connecting point is located at the rear side of the piston plate 601. The connecting hole The other end of 104 is connected with the cavity 1023. When the water flow pushes the rear diaphragm 7 to drive the piston plate 601 to move, the gas on the inner wall of the cavity 1023 enters the interior of the connecting sleeve 2 through the connecting hole 104, so that the inner circle diameter of the rear sealing edge 102 increases, thereby increasing the diameter of the water flow to increase the water flow. When the water flow is reversed, the piston plate 601 is reset under the push of the rear reset spring 4. When the piston plate 601 is reset, it pushes the gas inside the connecting sleeve 2 into the cavity 1023, causing the rubber membrane 1022 to expand, and when the rear diaphragm 7 and the rubber membrane 1022 are quickly fitted, it plays a buffering role.

[0045] As an embodiment of the present invention, refer to Figure 3 and Figure 8 The front side of the rear diaphragm 7 is provided with a mounting groove 701, the inner wall of the mounting groove 701 is connected with an arc-shaped top block 702, the mounting groove 701 and the arc-shaped top block 702 are filled with gas, and the front side of the rear diaphragm 7 is connected with a sealing film 703, and the sealing film 703 covers the mounting groove 701 and the arc-shaped top block 702. When the rear diaphragm 7 is attached to the rear sealing edge 102, the arc-shaped top block 702 is retracted into the mounting groove 701 under the pressure of the rear sealing edge 102, and the gas inside is compressed, so that the sealing film 703 on the rear side of the rear diaphragm 7 forms a concave surface, thereby increasing the thrust when the rear diaphragm 7 just contacts the water flow, making the rear diaphragm 7 easier to separate from the rear sealing edge 102. When the rear diaphragm 7 is separated from the rear sealing edge 102, the arc-shaped top block 702 protrudes under the push of the internal gas, so that the rear side of the rear diaphragm 7 is an arc-shaped convex surface, thereby reducing the head loss of the water flow when it flows.

[0046] As an embodiment of the present invention, refer to Figure 4 The fixing assembly 10 includes a trapezoidal block 1001, a connecting rod 1002, and a telescopic rod 1003. A groove 801 is provided on the inner wall of the front push rod 8, and slide grooves 802 are provided on both sides of the outer wall of the front push rod 8. The slide grooves 802 are communicated with the grooves 801. The trapezoidal block 1001 is connected to the inside of the slide groove 802. A baffle 105 is connected to the inner wall of the series tube 1. When the front diaphragm 9 is separated from the front sealing edge 103, the baffle 105 is located at the rear side of the trapezoidal block 1001. In the initial state, the trapezoidal block 1001 is engaged with the baffle 105 to fix the front push rod 8. The connecting rod 1002 is hinged to the right-angled side of the trapezoidal block 1001. The telescopic rod 1003 is connected to the front side of the inner wall of the groove 801. The rear end of the telescopic rod 1003 is hinged to the connecting rod 1002. A compression spring 1004 is provided on the outer wall of the telescopic rod 1003. The compression spring 1004 The front end is connected to the front side of the inner wall of the groove 801, and the rear end is connected to the telescopic rod 1003. The telescopic rod 1003 has the same axis as the top rod 602 and cooperates with the rear end of the top rod 602. When the top rod 602 pushes the telescopic rod 1003 to shorten, the telescopic rod 1003 pulls the connecting rod 1002 to retract the trapezoidal block 1001 into the slide groove 802, so that the trapezoidal block 1001 is separated from the baffle 105, thereby releasing the front push rod 8. The front return spring 5 is fixed so that the front push rod 8 can move. When the water flows backward, the front diaphragm 9 is pushed to push the front push rod 8 to move, so that the trapezoidal block 1001 contacts the baffle 105. When the baffle 105 contacts the hypotenuse of the trapezoidal block 1001, it will push the trapezoidal block 1001 to shrink into the slide groove 802. When the trapezoidal block 1001 moves to the rear side of the baffle 105, it pops out and engages with the baffle 105 to fix the front push rod 8.

[0047] As an embodiment of the present invention, refer to Figure 5 A buffer hole 106 is provided inside the wall of the series pipe 1, and both ends are connected to the inside of the series pipe 1. One end of the buffer hole 106 is located between the fixing plates 101 on the front and rear sides of the inner wall of the series pipe 1, and the other end is located in front of the front sealing edge 103. The inner wall of the buffer hole 106 is connected to a slider 11. The outlet diameter of the buffer hole 106 is smaller than the diameter of the slider 11, thereby limiting the separation distance between the front diaphragm 9 and the front sealing edge 103. One end of the slider 11 is connected to a fixing rod 12, and the fixing rod 12 is connected to the front diaphragm 9. When the water flows downstream, Part of the water flows into the buffer hole 106 from the rear end of the buffer hole 106. When the water flows backward, part of the water flows into the buffer hole 106 from the front end of the buffer hole 106 to guide the reverse flow of water, thereby further reducing the water hammer. At the same time, it will also push the slider 11 to move toward the rear end of the buffer hole 106 to squeeze out the water column on the rear side of the slider 11. Since the inside of the series tube 1 is full of water and the front end of the front series tube 1 is sealed by the rear diaphragm 7 to form a piston structure, there is a certain resistance to squeezing out the water column. The resistance when squeezing out the water column is used to further reduce the water hammer during reverse flow.

[0048] As an embodiment of the present invention, refer to Figure 5 and Figure 6 A reflux hole 107 is provided inside the tube wall of the series tube 1, and a rotating cover plate 13 is connected to one end of the reflux hole 107. The rotating cover plate 13 is arc-shaped, and the cross section of the rotating cover plate 13 is set to be arc-shaped, and is hinged to the inner wall of the series tube 1 near the rear diaphragm 7 side. The rotating cover plate 13 is provided with an arc groove 1301 near the front diaphragm 9 side. When the water flow inside the series tube 1 flows back, the rotating cover plate 13 opens under the thrust of the backflow, so that the backflow water inside the series tube 1 enters the reflux hole 107. The other end of the reflux hole 107 is connected to a duckbill tube 14, and finally the water flows out from the duckbill tube 14, and the water flow is directed to the front side of the front diaphragm 9, forming convection with the backflow water flow, thereby further reducing the convection, and the duckbill tube 14 allows the water flow to flow in one direction, avoiding the backflow, and the water flow flows into the reflux hole 107 from the end of the duckbill tube 14.

[0049] As an embodiment of the present invention, refer to Figure 8 The front sealing edge 103 forms a circle around the inner wall of the series pipe 1. The diameter of the series pipe 1 gradually decreases from the back to the front. When the water flows from a pipe with a large diameter to a pipe with a small diameter, the water pressure will decrease. Therefore, when the water flows backward, the water pressure during the backward flow is reduced, and the series pipe 1 is further protected. The minimum diameter is the same as the inner diameter of the front sealing edge 103. When the water flows downstream, the impact on the front sealing edge 103 is reduced, thereby reducing the head loss during the downstream flow.

[0050] As an embodiment of the present invention, refer to Figure 7A plurality of blades 15 are connected to the top of the rear diaphragm 7, and the cross section of the blades 15 is set to be L-shaped. The blades 15 are connected to a movable plate 1501 in a clockwise direction. The movable plate 1501 is connected to the blades 15 through a torsion spring, and there is an angle between the movable plate 1501 and the blades 15. When the water flows downstream, it passes through the blades 15 to drive the rear diaphragm 7 to rotate counterclockwise, so as to clean the mud and sand on the inner wall of the series pipe 1 and prevent the mud and sand from accumulating inside the pipe. When the water flows upstream, the water impacts the movable plate 1501, causing the movable plate 1501 to deflect, thereby buffering the impact force on the front side of the rear diaphragm 7 during the upstream flow.

[0051] As an embodiment of the present invention, refer to Figure 1 , Figure 5 and Figure 8 The front side of the front diaphragm 9 is set to be arc-shaped, and an annular groove 901 is opened on the front side of the front diaphragm 9. A moving block 902 is connected inside the annular groove 901. The moving block 902 is connected to the front push rod 8. When the downstream front diaphragm 9 is separated from the front sealing edge 103, the front push rod 8 pushes the moving block 902 to move so that a concave surface is formed on the front side of the front diaphragm 9, thereby increasing the thrust during countercurrent. When the front diaphragm 9 is in contact with the front rotating cover plate 13, the moving block 902 moves under the push of the water flow to form an arc surface with the front side of the front diaphragm 9, thereby reducing the countercurrent impact force on the sealed front diaphragm 9.

[0052] As an embodiment of the present invention, refer to Figure 8 The cross section of the base layer 1021 is set to a right-angled trapezoid, and the rear side is a bevel, which reduces the impact on the rear sealing edge 102 when flowing downstream. When the water flows over the bevel, it scours the bevel, avoiding the accumulation of mud and sand on the rear side of the rear sealing edge 102.

[0053] Working principle: The integrated check valve is installed in the drainage system through a flange. In order to prevent the check valve from being impacted by water hammer when starting and closing during the drainage process, front and rear return springs 4 are installed on the front and rear sides of the partition 3. When the water flow operates normally, the rear diaphragm 7 is pushed open first. When the rear diaphragm 7 is pushed open, the rear push rod 6 is pushed to squeeze the rear return spring 4 on the rear side of the partition 3, thereby buffering the impact force of the water flow pushing the rear diaphragm 7. When the rear push rod 6 is pushed, it drives the push rod 602 to move, and the push rod 602 pushes the fixing assembly 10 inside the front push rod 8 to unlock the fixing assembly 10. Under the action of the front return spring 5, the front push rod 8 pushes the front diaphragm 9 to move and separate from the front sealing edge 103, thereby allowing the pipeline to flow.

[0054] When the water flows backward, the rear diaphragm 7 loses the thrust of the water flow and is pushed by the rear return spring 4 to fit with the rear sealing edge 102 to achieve sealing. The front diaphragm 9 is pushed by the water flow to fit with the front sealing edge 103 to achieve sealing. When the reverse water flow pushes the front diaphragm 9, the front return spring 5 will be compressed, thereby buffering the water hammer during the reverse flow. At the same time, the fixing assembly 10 fixes the front push rod 8.

[0055] The front push rod 8 is fixed by engaging the trapezoidal block 1001 in the fixing assembly 10 with the baffle 105. When the push rod 602 contacts the fixing assembly 10, the telescopic rod 1003 in the fixing assembly 10 contracts and pulls the trapezoidal block 1001 into the slide groove 802 to release the fixation of the front push rod 8.

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An integrated double check valve, comprising a series pipe (1), characterized in that: It also includes a connecting sleeve (2), the inner wall of the series tube (1) is connected to a plurality of fixing plates (101), the connecting sleeve (2) is connected to the bottom end of the fixing plate (101), the connecting sleeve (2) is connected to a partition plate (3) inside, the front and rear sides of the partition plate (3) are respectively installed with a front return spring (5) and a rear return spring (4), the rear side of the partition plate (3) is provided with a rear push rod (6), the rear end of the rear push rod (6) is connected to a rear diaphragm (7), the front end of the rear push rod (6) is connected to a piston plate (601), the front side of the piston plate (601) is connected to the rear return spring (4), the front side of the partition plate (3) is connected to a front push rod (8), the rear end of the front push rod (8) is connected to the front return spring (5), the front side of the front push rod (8) A front diaphragm (9) is connected, the inner wall of the series tube (1) is connected with a rear sealing edge (102) and a front sealing edge (103), the rear sealing edge (102) is in contact with the rear side of the rear diaphragm (7), the front sealing edge (103) is in contact with the rear side of the front diaphragm (9), the inner wall of the front push rod (8) is connected with a fixing assembly (10), the front side of the piston plate (601) is connected with a push rod (602), when the front diaphragm (9) is in contact with the front sealing edge (103), the front push rod (8) compresses the front return spring (5) to store energy, and fixes the front push rod (8) through the fixing assembly (10), when the rear diaphragm (7) is separated from the rear sealing edge (102), the push rod (602) moves forward and releases the fixation of the fixing assembly (10).

2. An integrated double check valve according to claim 1, characterized in that: The rear sealing edge (102) comprises a base layer (1021) and a rubber membrane (1022); the base layer (1021) is connected to the inner wall of the series tube (1) and is located at the rear side of the rear diaphragm (7); the rubber membrane (1022) is connected to the outer wall of the base layer (1021); a cavity (1023) exists between the rubber membrane (1022) and the base layer (1021); a connecting hole (104) is opened on the inner wall of the fixing plate (101); one end of the connecting hole (104) is connected to the connecting sleeve (2), and the connecting point is located at the rear side of the piston plate (601); the other end of the connecting hole (104) is connected to the cavity (1023).

3. An integrated double check valve according to claim 2, characterized in that: The front side of the rear diaphragm (7) is provided with a mounting groove (701), the inner wall of the mounting groove (701) is connected to an arc-shaped top block (702), the front side of the rear diaphragm (7) is connected to a sealing film (703), and the sealing film (703) covers the mounting groove (701) and the arc-shaped top block (702).

4. The integrated double check valve according to claim 1, characterized in that: The fixing assembly (10) comprises a trapezoidal block (1001), a connecting rod (1002), and a telescopic rod (1003); a groove (801) is provided on the inner wall of the front push rod (8); slide grooves (802) are provided on both sides of the outer wall of the front push rod (8); the slide grooves (802) are connected to the grooves (801); the trapezoidal block (1001) is connected to the inside of the slide grooves (802); a baffle (105) is connected to the inner wall of the series tube (1); when the front diaphragm (9) is separated from the front sealing edge (103), the baffle (105) is located behind the trapezoidal block (1001). The connecting rod (1002) is hinged to the right-angled side of the trapezoidal block (1001); the telescopic rod (1003) is connected to the front side of the inner wall of the groove (801); the rear end of the telescopic rod (1003) is hinged to the connecting rod (1002); a compression spring (1004) is provided on the outer wall of the telescopic rod (1003); the front end of the compression spring (1004) is connected to the front side of the inner wall of the groove (801), and the rear end is connected to the telescopic rod (1003); the telescopic rod (1003) has the same axis as the top rod (602), and cooperates with the rear end of the top rod (602).

5. An integrated double check valve according to claim 4, characterized in that: A buffer hole (106) is provided inside the wall of the series tube (1), and both ends are connected to the inside of the series tube (1). One end of the buffer hole (106) is located between the fixed plates (101) on the front and rear sides of the inner wall of the series tube (1), and the other end is located in front of the front sealing edge (103). The inner wall of the buffer hole (106) is connected to a slider (11), and one end of the slider (11) is connected to a fixed rod (12), and the fixed rod (12) is connected to the front diaphragm (9).

6. An integrated double check valve according to claim 5, characterized in that: A reflux hole (107) is provided inside the wall of the series tube (1), one end of the reflux hole (107) is connected to a rotating cover plate (13), the rotating cover plate (13) is arc-shaped, the cross section of the rotating cover plate (13) is arranged to be arc-shaped, and the rotating cover plate (13) is hinged to the inner wall of the series tube (1) near the rear diaphragm (7), the rotating cover plate (13) is provided with an arc groove (1301) near the front diaphragm (9), and the other end of the reflux hole (107) is connected to a duckbill tube (14).

7. The integrated double check valve according to claim 1, characterized in that: The front sealing edge (103) forms a circle around the inner wall of the series pipe (1), and the diameter of the series pipe (1) gradually decreases from the back to the front, and the minimum diameter is the same as the inner diameter of the front sealing edge (103).

8. The integrated double check valve according to claim 3, characterized in that: A plurality of fan blades (15) are connected to the top of the rear diaphragm (7), the cross section of the fan blade (15) is set to be L-shaped, and the fan blade (15) is connected to a movable plate (1501) in a clockwise direction.

9. The integrated double check valve according to claim 5, characterized in that: The front side of the front diaphragm (9) is designed to be arc-shaped, and an annular groove (901) is provided on the front side of the front diaphragm (9). A moving block (902) is connected inside the annular groove (901), and the moving block (902) is connected to the front push rod (8).

10. An integrated double check valve according to claim 2, characterized in that: The cross section of the base layer (1021) is set to be a right-angled trapezoid, and the rear side is a hypotenuse.

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