A back pressure strong opening check valve

Abstract

The present invention relates to a check valve with forced opening with back pressure. The check valve comprises a valve body and a valve seat. The valve seat has a flow channel. A first valve flap is provided for rotation inside the valve body. A medium channel is provided on the first valve flap. A shaft is provided for rotation inside the valve body. The first valve flap is freely rotatably mounted on the shaft. A rocker is provided for synchronous rotation on the shaft. A second valve flap is provided on the rocker to realize forced opening and closing of the medium channel. A first sealing surface is provided on the second valve flap. A second sealing surface that seals with the first sealing surface is provided on the first valve flap. A driving mechanism for driving the shaft to rotate is provided on the valve body. The check valve with this structure can not only realize the requirement of forcibly opening the second valve flap under back pressure to allow the downstream medium to flow into the upstream; it can also meet the normal forward operation of the system. When the medium comes from the upstream of the pipeline, the driving mechanism drives the second valve flap to open. The positive medium pressure can directly push open the first valve flap, open the medium flow channel, and meet the requirements of normal operation.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and in particular to a back-pressure forced-opening check valve. Background Art

[0002] A check valve is an automatic valve that automatically opens and closes its disc based on the flow of the medium. It prevents backflow of the medium. Also known as a non-return valve, one-way valve, reverse flow valve, or back-pressure valve, its primary functions are to prevent backflow of the medium, reverse rotation of pumps and drive motors, and release of the medium from the container.

[0003] A check valve consists of a valve body, a valve seat, and a disc. The disc is pivotally mounted within the valve body via a pin. It allows the medium to flow in one direction only, preventing reverse flow. This valve operates automatically. The disc opens under the pressure of fluid flowing in one direction. When the fluid flows in the opposite direction, the fluid pressure and the weight of the disc cause the disc to seal against the sealing surface of the seat and close, thereby preventing reverse flow.

[0004] The check valve structure described above is currently a common structure, but it can only be used in ordinary situations, that is, in conditions with forward flow and reverse check. However, for some situations with multiple operating conditions, the check valve structure described above is not applicable. For example, in the HVAC field, the medium downstream of the check valve must be able to flow upstream of the check valve so that the medium of the operating unit can warm the turbine blades of the shut-down unit. In other words, the operating condition requires the valve disc to open under back pressure to allow the downstream medium to flow upstream. At the same time, it is required to have the functions of a normal check valve, that is, the operating condition requires normal forward operation and reverse check. For situations with such special operating conditions, the check valve structure of the conventional structure is not applicable. Summary of the Invention

[0005] The purpose of the present invention is to provide a back-pressure forced-opening check valve to solve the problem in the prior art that when the upstream pressure of the check valve is lower than the downstream pressure, that is, when there is back pressure, the check valve cannot open to allow the downstream medium to flow into the upstream medium, resulting in limited use of the existing check valve.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a back-pressure forced-opening check valve, comprising a valve body and a valve seat, the valve seat having a flow channel, a first valve disc being provided for rotation inside the valve body, the first valve disc being used to cooperate with the valve seat to realize the opening and closing of the flow channel, a medium channel being provided on the first valve disc, a shaft being provided for rotation inside the valve body, the first valve disc being freely rotatably installed on the shaft rod to realize its free rotation, a rocker being provided for synchronous rotation on the shaft rod, a second valve disc being provided on the rocker for cooperating with the medium channel to realize the opening and closing of the medium channel, a first sealing surface being provided on the second valve disc, and a second sealing surface being provided on the first valve disc for sealing cooperation with the first sealing surface; a driving mechanism for driving the shaft rod to rotate to drive the second valve disc to rotate to realize the forced opening of the medium channel is provided on the valve body.

[0007] The shaft is connected to the valve stem through a tooth-embedded structure, and the driving mechanism drives the shaft to rotate through the valve stem and the tooth-embedded structure. The tooth-embedded structure includes a central groove arranged at the end of the shaft, and a mounting groove is arranged on the groove wall of the central groove. The end of the valve stem has a loading portion that is inserted into the central groove, and the loading portion is provided with a force-applying protrusion that is inserted into the mounting groove and is used to contact the groove wall of the mounting groove to transmit power; the width of the force-applying protrusion is smaller than the groove width of the mounting groove so that there is an idle stroke between the valve stem and the shaft during the rotation process, so that the second valve disc can freely close the medium channel under the action of the medium backflow thrust and / or its own gravity.

[0008] The first valve disc is provided with a first limiting rib plate, which contacts the inner wall of the valve body to limit the opening angle of the first valve disc.

[0009] The second valve disc is provided with a second limiting rib plate, which contacts the inner wall of the valve body to limit the opening angle of the second valve disc.

[0010] A valve disc mounting hole is provided on the rocker arm, and the second valve disc includes a valve disc plate and a mounting column for being installed in the valve disc mounting hole. A mounting step is formed at the connection between the mounting column and the valve disc plate, and an adjusting gasket is provided on the mounting step. One side of the adjusting gasket contacts the step surface of the mounting step, and the other side contacts one end face of the valve disc mounting hole. The upper limit position of the other end face of the valve disc mounting hole is matched with a valve disc cover, and the valve disc cover is connected to the mounting column by screws.

[0011] The valve flap mounting hole is a tapered hole, and the mounting column is a cylinder, so that the second valve flap can automatically align with the valve flap mounting hole to achieve sealing with the first valve flap.

[0012] A counterweight is provided on the first valve flap.

[0013] The first sealing surface and the second sealing surface are both sealing surfaces formed by hard metal surfacing.

[0014] The beneficial effects of the present invention are as follows: when back pressure exists downstream of the check valve in the pipeline and the valve needs to be forcibly opened, the drive mechanism rotates the shaft and the second valve disc thereon, opening the medium channel on the first valve disc. The second valve disc opens to connect the upstream and downstream of the check valve, allowing the medium to flow from the downstream of the check valve to the upstream. This achieves the forced opening of the second valve disc under back pressure to connect the upstream and downstream of the check valve, meeting the requirement of opening the valve with back pressure on site. When the system is operating normally in the forward direction, the medium flows from the upstream of the pipeline, and the drive mechanism can drive the second valve disc to open. The positive medium pressure can directly push the first valve disc open, opening the medium flow channel and achieving normal operation requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of an embodiment of a back pressure forced opening check valve of the present invention. Figure 1 ;

[0016] Figure 2 This is a schematic diagram of the structure of an embodiment of a back pressure forced opening check valve of the present invention. Figure 2 ;

[0017] Figure 3 yes Figure 2 A partial enlarged view of point A in the middle;

[0018] Figure 4 Schematic diagram of the installation structure between the second valve disc and the rocker;

[0019] Figure 5 It is a structural diagram of the first valve disc. DETAILED DESCRIPTION

[0020] An embodiment of a back pressure strong opening check valve of the present invention is as follows Figure 1-Figure 5 As shown, it includes a valve body 1 and a valve seat 2. The valve seat has a flow channel. A first valve flap 4 is rotatably provided inside the valve body. The first valve flap is used to cooperate with the valve seat to realize the opening and closing of the flow channel. A medium channel 22 is opened on the first valve flap. A shaft 3 is rotatably provided inside the valve body. The first valve flap 4 is freely rotatably mounted on the shaft to realize its free rotation. That is, the first valve flap can freely rotate relative to the shaft, and the first valve flap and the shaft do not interfere with each other. Specifically, as shown in FIG. Figure 5 As shown, the back of the first valve flap 4 is provided with a first mounting portion 21, which is provided with a first mounting hole that is sleeved onto the shaft. When the fluid medium flows in the forward direction, the first valve flap is pushed open by the force of the fluid medium, achieving normal operation. In the event of a field fault, such as a power outage or air loss, the first valve flap can automatically close due to gravity and the thrust of the fluid medium's backflow.

[0021] A rocker 13 is provided on the shaft for synchronous rotation, and a second valve flap 5 is provided on the rocker for cooperating with the medium channel to realize the opening and closing of the medium channel. Figure 4 As shown, the rocker includes a second mounting portion 19, the second mounting portion is provided with a second mounting hole sleeved on the shaft rod, the hole wall of the second mounting hole is provided with a first key groove 20, and the shaft rod is provided with a second key groove, and flat keys are installed in the first key groove and the second key groove to realize the synchronous rotation of the rocker with the shaft rod.

[0022] A valve flap mounting hole 14 is provided on the rocker 13. The second valve flap includes a valve flap plate and a mounting post 15 for mounting in the valve flap mounting hole. The connection between the mounting post and the valve flap plate forms a mounting step 18. An adjustment gasket is provided on the mounting step. One side of the adjustment gasket contacts the step surface of the mounting step, and the other side contacts one end face of the valve flap mounting hole. The upper limit position of the other end face of the valve flap mounting hole is matched with a valve flap cover 16. The valve flap cover is connected to the mounting post by screws 17. The complete sealing fit between the second valve flap and the second valve flap can be adjusted by changing the thickness or number of the adjustment gaskets. The valve flap mounting hole 14 is a conical hole, and the mounting post 15 is a cylinder, so that the second valve flap can automatically align with the valve flap mounting hole to achieve a seal with the first valve flap. A counterweight block 8 is provided on the first valve flap. The function of the counterweight block is to enable the first valve flap to close quickly when the fluid medium stops.

[0023] A first sealing surface 12 is provided on the second valve flap 5, and a second sealing surface 11 that seals with the first sealing surface is provided on the first valve flap 4. Both the first sealing surface and the second sealing surface are sealing surfaces formed by hard metal surfacing welding, and the hard metal can be a cobalt-chromium-tungsten alloy. A driving mechanism is provided on the valve body to drive the shaft to rotate so as to drive the second valve flap to rotate and thereby forcibly open the medium channel. The driving mechanism can be a pneumatic actuator or a driving motor that can drive the shaft to rotate. The shaft is connected to the valve stem 7 through a tooth-embedded structure 6, and the driving mechanism drives the shaft to rotate through the valve stem and the tooth-embedded structure. Specifically, the tooth-embedded structure includes a central groove provided at the end of the shaft, a mounting groove provided on the groove wall of the central groove, and a mounting portion provided on the end of the valve stem to be inserted into the central groove, and a force-applying protrusion provided on the mounting groove for contacting the groove wall of the mounting groove to transmit power. The width of the force-applying protrusion is smaller than the width of the mounting groove so that there is an idle stroke between the valve stem and the shaft during rotation, so that the second valve flap can freely close the medium channel under the action of medium backflow thrust and / or its own gravity.

[0024] The first valve flap 4 is provided with a first limiting rib 10, which contacts the inner wall of the valve body to limit the opening angle of the first valve flap. The second valve flap 5 is provided with a second limiting rib 9, which contacts the inner wall of the valve body to limit the opening angle of the second valve flap. This prevents the first and second valve flaps from opening too wide, which could cause the first and second valve flaps to float on the fluid during backflow, preventing the valve from closing quickly.

[0025] When back pressure exists downstream of the check valve in the pipeline and the valve needs to be forced open, the drive mechanism rotates the shaft and the second valve disc on it. The second valve disc opens and opens the medium channel on the first valve disc, connecting the upstream and downstream of the check valve. Under the action of back pressure, the medium flows from the downstream of the valve disc to the upstream, thus forcing the second valve disc to open under back pressure to connect the upstream and downstream of the check valve. When the system is operating normally, the medium flows from the upstream of the pipeline, and the drive mechanism can drive the second valve disc to open. The first valve disc is pushed open by the force of the fluid medium, and the system operates normally. When the system fails or needs to be shut down, or when power or air is lost, the first and second valve discs quickly close by their own weight and the thrust of the medium backflow to prevent the fluid medium from flowing back. The drive mechanism plays an auxiliary closing role.

[0026] In other embodiments of the present invention, while ensuring that the first valve flap and the second valve flap can be closed smoothly, the first limiting rib may not be provided on the first valve flap, and the second limiting rib may not be provided on the second valve flap.

Claims

1. A back pressure forced opening check valve, comprising a valve body and a valve seat, wherein the valve seat has a flow passage, a first valve disc is rotatably provided inside the valve body, and the first valve disc is used to cooperate with the valve seat to realize opening and closing of the flow passage, characterized in that: The first valve disc is provided with a medium channel, and a shaft is provided for rotation inside the valve body. The first valve disc is freely rotatably mounted on the shaft to realize its free rotation, and a rocker is provided on the shaft for synchronous rotation, and a second valve disc for cooperating with the medium channel is provided on the rocker to realize opening and closing of the medium channel, and a first sealing surface is provided on the second valve disc, and a second sealing surface that seals with the first sealing surface is provided on the first valve disc; a driving mechanism is provided on the valve body to drive the shaft to rotate to drive the second valve disc to rotate to realize forced opening of the medium channel; the shaft is connected to the valve stem through a tooth structure, and the driving mechanism drives the shaft to rotate through the valve stem and the tooth structure, and the tooth structure includes a central groove provided at the end of the shaft stem, and a mounting groove is provided on the groove wall of the central groove, and the end of the valve stem has a mounting portion that is mounted in the central groove. The mounting portion is provided with a force-applying protrusion which is installed in the mounting groove and is used to contact the groove wall of the mounting groove to transmit power; the width of the force-applying protrusion is smaller than the groove width of the mounting groove so that there is an idle stroke between the valve stem and the shaft rod during the rotation process, so that the second valve disc can freely close the medium channel under the action of the medium backflow thrust and / or its own gravity; a counterweight block is provided on the first valve disc.

2. The back pressure forced opening check valve according to claim 1, characterized in that: The first valve disc is provided with a first limiting rib plate, which contacts the inner wall of the valve body to limit the opening angle of the first valve disc.

3. The back pressure forced opening check valve according to claim 2, characterized in that: The second valve disc is provided with a second limiting rib plate, which contacts the inner wall of the valve body to limit the opening angle of the second valve disc.

4. The back pressure forced opening check valve according to any one of claims 1 to 3, characterized in that: A valve disc mounting hole is provided on the rocker arm, and the second valve disc includes a valve disc plate and a mounting column for being installed in the valve disc mounting hole. A mounting step is formed at the connection between the mounting column and the valve disc plate, and an adjusting gasket is provided on the mounting step. One side of the adjusting gasket contacts the step surface of the mounting step, and the other side contacts one end face of the valve disc mounting hole. The upper limit position of the other end face of the valve disc mounting hole is matched with a valve disc cover, and the valve disc cover is connected to the mounting column by screws.

5. The back pressure forced opening check valve according to claim 4, characterized in that: The valve flap mounting hole is a tapered hole, and the mounting column is a cylinder, so that the second valve flap can automatically align with the valve flap mounting hole to achieve sealing with the first valve flap.

6. The back pressure forced opening check valve according to claim 1, characterized in that: The first sealing surface and the second sealing surface are both sealing surfaces formed by hard metal surfacing.

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