EA044471B1 - CHECK VALVE - Google Patents

Description

Field of technology

The present invention relates to check valves.

State of the art

Check valves (also known as non-return valves, butterfly valves, check valves, one-way valves, and one-way valves) are commonly used on the outlet (pipe) of pumps/compressors to prevent backflow from the pressure piping network back through the compressor. the time it stops (or when a malfunction occurs that causes it to stop). Backflow can cause pressurized fluid to leak into the atmosphere through the compressor, potentially in an unexpected manner, with potential damage to the compressor and/or electrical system.

Conventional check valves for large air/water applications are designed with a valve-like valve, wherein the weight of the valve and/or a spring or resilient component provides a bias that tends to close the valve and, in the presence of higher pressure on the compressor side, greater than the pressure on the discharge side , will strive to open the damper. Such known valves may also be of the butterfly valve design/type or of S-shaped valves, ball valves and plug valves.

Since such valves depend on fluid flow to keep them open, they are usually never fully open (since in such a scenario there is no force opposing the weight/spring force to keep them open). This means that even in the case of optimal constant flow, they create some pressure drop across the (partially) open damper element. Even with constant flow, traditional dampers can oscillate due to vortex formation.

Conventional positive displacement compressors/devices typically create a pulsating flow at their outlet as each successive chamber containing pressurized fluid opens into an outlet pipe.

It has been recognized that such flow pulsations can be a problem for check valves because they tend to oscillate between open and partially open states (ie states in which the valve flapper element provides more opening than in the other state).

This results in an even greater pressure drop, since when a high pulse occurs, the valve is still partially closed compared to the previous low pressure phase. The resulting vibration of the damper element is noisy and can lead to earlier failure of the valve due to fatigue.

The inventors of the present invention seek to solve the problem of steady pressure drop and jitter in pulsating flow. An advanced check valve has been developed for this purpose, which may include an electrical control input and a secondary trigger mechanism. The improved check valve may be configured to be used with compressed air as the primary medium, but may also be used for other fluids or incompressible fluids or at the inlet of a fluid transfer device (eg, a pump or compressor).

Disclosure of the invention

According to a first aspect of the present invention, there is provided a check valve that includes a shutter and a biasing mechanism, wherein the biasing mechanism is configured to move the shutter to a closed state, wherein the check valve further includes an actuator assembly configured to selectively trigger to drive the shutter to an open state, wherein the check valve includes a controller having a control input signal through which the controller causes the actuator assembly to be selectively started and the actuator assembly to be selectively turned off.

The check valve may be any type of check valve.

The present invention can be considered as an improved check valve.

The controller can be considered as a device for controlling the operating mode of the check valve.

Upon startup, the actuator assembly may preferably be used to lock the bias mechanism.

The present invention may include a passive valve that is typically opened by fluid flow, but which inherently still results in a pressure drop across it.

In general, the present invention includes an actuator that moves the valve to a more open position than would be achieved by fluid flow alone, thereby reducing pressure drop (and reducing vibration/wear, etc. .). When receiving a certain type of signal, the actuator preferentially moves the gate further so that it does not impede the flow (relative to the surface area presented to the flow), compared to how the flow itself would move it under the influence of the flow and

- 1 044471 associated pressure drop. The actuator assembly can be thought of as a device that allows fluid flow to cause the valve to open to a greater extent. The actuator assembly can be thought of as a device configured to move the valve to open it more so that it can move under the influence of flow, thereby reducing the pressure drop across the valve.

The actuator assembly may be configured to cause the gate to open from a less open state to a more fully open state. The actuator assembly may be configured to be triggered only when the valve is in a partially open state (eg, due to fluid flow). The actuator assembly may be configured to open the shutter to a fully or substantially fully open state.

The controller may be configured to cause the actuator assembly to be activated to hold the valve open during operation of the fluid displacement device to force fluid through a fluid opening of said device, wherein a check valve is connected to said fluid opening. Reference to the check valve being connected to a fluid opening (eg, an inlet or an outlet) of a fluid displacement device includes a direct/direct connection thereto, and also includes an indirect connection, for example, in which between one or more intermediate components or assemblies (for example, a filter, muffler or oil separator) are provided with a fluid opening and a check valve. The operating state of the check valve may be at least partially dependent on the operating state of the fluid displacement device (as indicated by a control input signal).

The controller may be configured to disable the actuator assembly in response to receiving a control input signal that indicates either disabling the fluid displacement device or indicating a change in the operating state of the fluid displacement device from an operating state to an inoperative state. This can be achieved either by the absence or interruption of a signal that indicates operation of the fluid displacement device, or by a signal that (positively) indicates a change in operating state. The controller may be configured to disable the actuator assembly (to stop holding the valve open) in response to the absence of a signal to the controller indicating operation of the fluid displacement device, the check valve being connected to said fluid opening.

The check valve can be thought of as a device having a default operating state of a bias mechanism, which is preferably a passive device/object. This may be due to a missing or interrupted control input signal.

The control signal input may comprise a terminal or port configured to receive an electrical signal.

The signal to open the valve can be a flow measurement (using one or various known flow measurement devices from mechanical (damper, etc.) to electrical (thermal, surface acoustic waves, vortex with bluff body (vibration measuring), etc.) to pressure meters (Pitot tube, etc.).

It is assumed that the valve is already partially open (in passive mode), after which the metering device detects the flow and actuates the valve to open more fully.

The actuator assembly may include a pressure actuated actuator.

The controller may be configured to cause one of two fluid pressure sources to act at least partially on the actuator assembly.

The connection of the actuator to one pressure source allows the displacement mechanism to function, and the connection to another pressure source allows the valve to move to the open state. It should be understood that this involves connection to a vacuum and not to a (positive) pressure source, in which when connected/switched to a vacuum source the valve is forced open.

The controller may include a switch configured to control which pressure source the actuator assembly is connected to.

The actuator assembly may include a movable component, opposite sides or ends of which are configured to be subjected to a corresponding pressure source, wherein the fluid pressure exerted on at least one of the sides/ends of the components is controlled by a controller. The movable component may include a piston movably mounted within the cylinder, or a diaphragm, or bellows, or diaphragm assembly.

The controller may be configured to selectively apply a differential pressure to the movable component, with one side/end of the movable component being subjected to a higher fluid pressure than the other side/end of the movable component.

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Any pressure difference may be applied within the fluid system (in which the check valve operates) or between the fluid system and the atmosphere or other pressure reference or source. For example, a vacuum system in which the difference between a pipeline (always under partial vacuum) and the atmosphere or other pressure source can be used to actuate a valve.

While the method of driving the actuator assembly may use pressure from a piping/fluid system for actuation, it is also possible to use other driving forces, including an electromagnetic actuator (a cylinder replacement electromagnet, or a motor and rack, replacing the cylinder), actuator based on shape memory metal, or some other type.

The controller may further provide the ability to selectively subject both ends/sides of the movable component to substantially the same fluid pressure.

The check valve may be configured such that the fluid pressure that is applied to one side/end of the movable component cannot be changed to another pressure by the controller. Said side/end of the movable component may be configured to be substantially permanently connected to a single source of fluid pressure.

The controller may include a switch valve. The switch valve may have a fluid outlet and a first fluid inlet and a second fluid inlet, the controller being configured to be used to selectively connect the fluid outlet to either the first fluid inlet or a second fluid inlet.

The actuator assembly may include a piston movably mounted within the piston chamber, the piston defining two subchambers, the first subchamber being selectively coupled to the first pressure and the second pressure, and the second subchamber being coupled to the first pressure. The actuator assembly may comprise a single piston operating in a cylinder. The piston may be configured to move/operate within a portion of the valve's range/stroke.

The switching valve may be configured to control which of the first fluid pressure and the second fluid pressure is connected to the second subchamber.

The actuator assembly may include a first passage connecting the controller to the first fluid pressure and a second passage connecting the controller to the second fluid pressure.

When the controller may use connection control with the first fluid pressure and the second fluid pressure, the first fluid pressure is lower than the second fluid pressure, or vice versa. In addition, the controller may use the first and second pressures to provide either a differential pressure to the actuator assembly or substantially equalize the pressures to the actuator assembly.

The first fluid pressure may be atmospheric pressure, and the second fluid pressure may be the pressure of a fluid in a fluid-containing channel to which the check valve is operably connected.

The check valve may include a link connecting the actuator assembly to the valve.

It should be understood that the controller may alternatively or additionally include a pneumatic assembly or a manually operated switch (to control the actuator assembly).

In use, the check valve may be connected downstream (i.e., to a fluid outlet) of a fluid displacement device (e.g., a compressor) or upstream of a fluid inlet of a fluid displacement device (e.g., a suction pump).

The bias mechanism is preferably a passive (rather than active) mechanism for moving the shutter to a closed state. The actuator assembly can be thought of as a device configured to actively open the shutter and not designed or configured to (actively) close the shutter, i.e. the activation of the actuator serves solely to move the shutter to the open state. However, the actuator assembly may be configured to (actively) close the shutter in addition to being able to move the shutter to an open state. The actuator assembly may be referred to as a gate opening actuator.

The expression bias mechanism may be interpreted to include any device or arrangement that causes the breech to move toward a closed state, and may include a spring or other resilient component and/or may include a breech weight or a weighted portion provided with the breech to achieve this result. . The bias mechanism may be configured to apply a high or very high/significant force to the bolt. This results in the shutter closing very quickly. More generally, the bias mechanism may be referred to as a gate bias or bias arrangement.

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The actuator assembly can be thought of as a locking mechanism for the bias mechanism.

By movable component is meant a component configured to move (translationally or angularly) in response to applied differential pressure.

The controller can be thought of as being configured to receive a control signal and selectively trigger when the actuator assembly causes the gate to open.

The switching valve may include an electromagnet. The switch valve may comprise a three-way, two-way switch valve (which can be controlled by one or more solenoids). The switch valve can control the connection of the actuator assembly to one of two pressure sources.

The fluid that the check valve is designed to regulate is preferably a fluid in the gaseous state.

The piston may be connected to a lever that is connected to the bolt. The lever may comprise an articulated lever or linkage.

The piston chamber may include a cylinder.

By open state it is meant that the shutter is in a partially open, or fully open, or substantially fully open state.

It should be understood that the actuator assembly does not necessarily have to move through its entire range of motion to move the bolt to the open state, but instead can be configured to have only an active stroke, or so that the bolt can be moved over a limited range of partially open until fully open.

The actuator assembly may be configured to lock the shutter in the open state. The actuator assembly may include a latch that, when the actuator assembly is activated, locks or holds the shutter open, with the shutter in the open state being released when the actuator assembly is subsequently activated or disabled. This may include a first trigger to force the gate open and a second trigger to release the gate from the open state.

The controller may include a damper, a time lag/start delay for response, or hysteresis to prevent the pulsation or pressure wave from affecting the actuator/system.

According to a second aspect of the present invention, there is provided a fluid displacement system that includes a check valve according to the first aspect of the present invention and a fluid displacement device.

According to a third aspect of the present invention, there is provided a fluid displacement device, the fluid opening of which is provided with a check valve according to the first aspect of the present invention.

The check valve may preferably be used with any type of fluid displacement device, including a rotating piston and cylinder device that includes a rotor and a stator, wherein the stator at least partially defines an annular cylindrical space and the rotor may be shaped like an annular cylinder. wherein the rotor comprises at least one piston that extends from the rotor ring into an annular cylindrical space or working chamber, and in use, the at least one piston moves circumferentially through the cylindrical space as the rotor rotates relative to the stator, wherein the rotor housing is sealed relative to the stator, wherein said device further comprises a flap of the cylindrical space, mounted for movement relative to the stator in a closed position, in which said means with the flap divides the annular cylindrical space, and in an open position, in which the means with the flap allows passage of at least one piston, and the flap of the cylindrical space may comprise a rotatably mounted flap (disk). An example of such a device is disclosed in EP 2334908. The check valve can also be used with a dynamic or positive displacement pump or device, including: rotary pumps (eg gear pumps, screw pumps and centrifugal vane pumps), reciprocating pumps (eg , plunger pumps, piston pumps, diaphragm pumps and rotary piston pumps), linear pumps (such as rope pumps, chain pumps and cavitation screw pumps), linear, rotary and piston compressors.

The check valve may include a valve position sensor or operating status sensor that may monitor valve position, pressure drop across the valve, and/or flow through the valve.

Check valves are often used when multiple gases are mixed into one gas stream. A check valve can be installed on each of the individual gas streams to prevent mixing of gases in the original source.

Check valves are also used in many fluid systems, such as chemical

- 4 044471 industrial factories and power plants. Applications in the nuclear industry include water control systems, vent lines, makeup waters, miscellaneous process systems, N2 systems, and monitoring and sampling systems. In the aerospace industry, check valves are used where high vibration, large temperature differences and corrosive fluids are present.

The check valve may be a stand-alone device and therefore may be installed in the pipeline, not necessarily near the compressor.

Any of the foregoing aspects or additional aspects of the present invention may include one or more features, alone or in combination, shown in the drawings and/or disclosed in the description.

Brief description of drawings

Various embodiments of the present invention are now disclosed, by way of example only, with the drawings showing the following:

in fig. 1 shows the axonometric appearance of the check valve;

in fig. 2 is a perspective view illustrating various internal components of the check valve;

in fig. 3 shows a check valve in a longitudinal section;

in fig. 4 shows the check valve solenoid control unit on an enlarged scale;

in fig. 5 shows a schematic diagram of a check valve;

in fig. 6 shows a check valve connected to the fluid outlet of the compressor.

Carrying out the invention

Further disclosed is a check valve comprising a gate (or flapper) movable from an open state to a closed state and vice versa, and a pressure actuated actuator (which may be referred to as a secondary actuation mechanism) to selectively hold the valve open. and, when in use, the interlocking bias mechanism and its tendency to push or move the valve to a closed state. The embodiment described below relates to a check valve provided at or connected to an outlet of an air compressor.

Next, FIGS. 1 and fig. 2. The main body or frame of the check valve 1 is similar to a traditional check valve: it contains a flapper 2 that closes under its own weight (or by/in addition to the compression force of a spring, which may be a coil spring or a pneumatic spring). The check valve may also be a butterfly valve. The check valve 1 has a fluid inlet 1a and a fluid outlet 1b.

The damper 2 is mounted on a rotary shaft 3. The rotary shaft 3 allows the damper to rotate around its axis from an open state to a closed state and vice versa.

In the illustrated example, the above-mentioned secondary firing mechanism comprises a piston 5 movably mounted in a cylinder 6. The piston is connected to an articulation linkage which includes a piston rod 7a and a lever 7b, the parts 7a and 7b being rotatably connected. The lever 7b is rigidly connected to the shaft 3 so that the activation of the actuator assembly actuates/causes the movement of the piston to cause the valve 2 to open.

Piston 5 divides the cylinder space into two subchambers. One side of the piston 5 (shown as the top in the drawings, although the orientation is not important) is always connected to the atmosphere or atmospheric pressure through the vent 10. The other side of the piston 5, that is, the lower subchamber, as shown in the drawings, can be selectively connected to either atmospheric pressure or a pressurized fluid (ie compressed air) in a pipe to which valve 1 is connected. Said pipe is connected to a fluid outlet of the compressor and a valve located downstream of the compressor. Piston 5 is hermetically connected to cylinder 6 to prevent leakage of compressed air into the atmosphere. A pipe connection is provided on the inlet side of the valve 2 to allow the valve to function initially if the pipeline starts at atmospheric pressure.

The check valve 1 further includes a control signal port or terminal 12 configured to receive a signal (directly or indirectly) from the compressor. Input to port 12 controls the operation of an electromagnetic switching valve, schematically illustrated by reference number 13. The valve includes an electromagnet configured to switch a pressure source to which the lower subchamber of chamber 6 is connected. Switching valve 13 is connected to atmospheric pressure through a channel or inlet 13a , and it is also connected to the air pressure inside the pipe, which was released by the compressor through channel 13b. Channel 13b connects an opening in the check valve body located upstream of flapper 2, as best seen in FIG. 3, with a switching valve 13. The switching valve 13 additionally has an outlet 13c, which is fluidly connected to the lower subchamber of the cylinder 6.

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Vent 10 and inlet 13a connected to atmospheric pressure can be considered, more generally, to be connected to a reference pressure, allowing differential pressure to be achieved, as described in more detail below. In addition, the vents 10 and 13a may be connected to a compressor inlet. This arrangement is advantageous when a toxic gas is used that would otherwise be released into the atmosphere, but instead may be present in a fluid system.

In particular, terminal 12 is configured to receive a signal that indicates whether the power supply to the compressor changes from an on state to an off state, or the compressor otherwise stops operating (at least as regards the supply of compressed air). Reception of a signal indicating a state transition activates the secondary trigger mechanism. In practice, this control of the check valve 1 can be achieved by the actuator causing the damper 3 to remain open until a signal is received indicating that the compressor compression function is in operation/engaged to supply/ release of compressed air. In the absence of receiving such a signal at the terminal 12, the switching valve solenoid is configured to connect a pressure source for the lower subchamber to atmospheric pressure. Alternatively, a predetermined signal may be provided to the terminal 12 that indicates a change in the operating state of the compressor to an off state or an off state with respect to its compression functionality. Therefore, the input terminal 12 is connected, directly or indirectly, to the compressor to control the actuator. Thus, the operating mode of the valve depends on the operating condition of the compressor.

The switching valve 13 contains a single triggered three-way solenoid valve. It should be understood that the switching valve may also be a valve (or valves) actuated by means other than electrical actuation, such as mechanical, hydraulic, or pneumatic means. For example, a corresponding subchamber of the actuator assembly may be coupled via a conduit to a fluid displacement device and then to a pressure sensor that provides a signal to the controller.

Alternatively, the switching valve 13 may comprise two solenoid-controlled air control valves that change the environment to which the underside of the cylinder 6 is connected. One of the valves is typically open; the other is (usually) closed. In the absence of an electrical signal being applied, the valves default to these positions. When an electrical signal is applied, they go into the opposite state.

When no electrical signal is supplied through the input terminal 12, the check valve 1 operates like a conventional check valve: it opens when the pressure at the inlet port is greater than that at the outlet port, and closes when the opposite is true. The movement is provided by line pressure acting on the valve, causing it to rise and open when the pump starts, and to fall under its own weight and/or under the action of a spring when the flow is reversed, and to close completely due to the reversal of pressure through it. Since the lower part of the cylinder 6 is connected to the atmosphere by means of a valve 13 (the upper subchamber is always connected to the atmosphere), there is no significant force acting on the piston 5, except for some damping due to small air passages in the secondary firing system. Piston 5 (which is mechanically connected to the check valve flap) is moved by the flap and applies only a small damping force to flapper 2.

When an electrical signal is applied in response to the signal received at terminal 12, the electromagnet causes the air valves to disconnect the air under the piston 5 from the atmosphere and instead connect it to the air in the pipe that is immediately upstream of the damper in the main pipe. This means that as long as the pressure in the pipe exceeds atmospheric pressure, an upward force will act on the piston in all positions of damper 2, causing the damper to open (and remain open). The piston 5 and its connections 7a and 7b with the valve are of such dimensions (through their respective surface areas) that the expected pressure in the pipeline under all operating conditions is sufficient to hold the valve fully open (to counteract the closing force of its weight and/or any attached spring). Since the shutter 2 is fully open, it does not cause a drop in the pressure of the fluid flowing in the main pipe. Conversely, the flow in the pipe applies very little force to the flapper, and its position is controlled mainly by the piston 5. The area of the piston can be smaller than the area of the flapper 2.

Thus, when an electrical signal is applied, check valve 1 will not operate as a normal or ordinary check valve, since it does not partially close when a low pressure vacuum passes through it (assuming that the lowest pressure in the pulse is still above atmospheric pressure and is sufficient to hold the piston at the top of its stroke due to resistance to the closing force of the valve). The valve will also not close if the flow is reversed, since the pressure in the pipe will likely still be above atmospheric pressure even if the flow is reversed.

Claims (12)

changes to the opposite (this will happen until the pipeline network is completely drained and the pressure in it drops to atmospheric pressure). This means that when an electrical signal is applied, the non-return valve is blocked or bypassed, and in almost all circumstances (when an electrical signal is applied) it becomes a manual or positive-open valve (without the ability to manually close it). In order to satisfy the non-return criterion of the check valve to protect the pipeline and compressor, the electrical signal is interrupted when any problem occurs. This can be achieved by using a series of sensors on the compressor and/or piping, and by connecting the valve to the same electrical network as the compressor. Such measures are protective measures (which cause the check valve to go into passive mode) and may involve detecting this, for example, when there is a loss of power. Next, FIG. 6, which shows a check valve 1 connected to the fluid outlet of the rotating piston and cylinder device 50. It should be understood that the shutter 2 in FIG. 2, 3 and 4 are in the closed state. In fig. 5, valve 2 is shown in a partially open state as a result of the pressure applied by the fluid flow, but without the assistance of an actuator. CLAIM 1. A check valve comprising a gate (2) and a bias mechanism, the bias mechanism being configured to apply a load to the gate towards a closed state, the check valve further comprising an actuator assembly configured to be selectively triggered to drive the gate more fully open state from a less open state, the check valve includes a controller having a control input signal through which the controller causes selective activation of the actuator assembly, the signal indicating that the valve is in a less open state provided by fluid flow or indicating the presence of fluid flow to the shutter. 2. The check valve of claim 1, wherein the actuator assembly is configured to, in use, block the bias mechanism when the actuator assembly is activated. 3. The check valve according to claim 2, wherein the controller is configured to maintain an operating mechanism assembly for holding the valve (2) in an open state during operation of the fluid displacement device for displacing fluid through the fluid opening of the said device, wherein a check valve is connected to said fluid opening. 4. The check valve of claim 3, wherein the controller is configured to disable the actuator assembly in response to receiving a control input signal that indicates either a disabling of the fluid displacement device or a change in the operating state of the fluid displacement device from an operational state to an inoperative state state. 5. A check valve according to any of the previous claims, wherein the actuator assembly is configured to open the valve (2) to a greater extent compared to a partially open state when activated. 6. A check valve as claimed in any one of the preceding claims, wherein the controller comprises a terminal or port configured to receive an electrical signal, a pneumatic signal, or a mechanical signal. 7. A check valve as claimed in any one of the preceding claims, wherein the actuator assembly comprises a pressure actuated actuator. 8. A check valve as claimed in any one of the preceding claims, wherein the controller is configured to cause one of two fluid pressure sources to act at least partially on the actuator assembly. 9. The check valve according to claim 8, wherein the connection of the actuator to one pressure source allows the displacement mechanism to function, and the connection to another pressure source allows the application of a load to the valve to move it to the open state. 10. The check valve according to any one of claims 8 or 9, wherein the controller includes a switch configured to control which pressure source the actuator assembly is connected to. 11. A check valve as claimed in any one of the preceding claims, wherein the actuator assembly comprises a movable component, opposite sides or ends of which are configured to be subjected to a corresponding source of pressure, the fluid pressure acting on at least one of the sides/ends components, controlled by a controller. 12. The check valve of claim 11, wherein the controller is configured to selectively apply differential pressure to the movable component, wherein one side/one -