RU2546884C1 - Check rotary valve - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: check rotary valve contains a body with bonnet, and installed in the body rotary poppet with seat, and stock passing through the bonnet. The stock is hingedly connected with the poppet. The valve is equipped with the pneumatic drive of the stock for the poppet closing, and with spring drive of the stock for its passive opening. The valve is equipped with control system activating the pneumatic drive when the medium pressure inside the valve achieves the specified value of closing, and deactivating the pneumatic drive when the medium pressure inside the valve achieves the specified value of opening.

EFFECT: widening of range of possible use of check rotary valve, improved technical and economic characteristics due to increased safety, reliability, and increased service life.

7 cl, 5 dwg

Description

The invention relates to reinforcing means for the safety of power plants, and in particular to reverse gates. These devices are installed in piping systems in order to prevent abnormal situations associated with an emergency change in the direction of flow of the working medium.

Swing check valves have a swivel plate inside the casing, which overlaps the flow area by pressing the shutter against the valve seat, and the plate is placed in the position to open the shutter with the flow of the working medium during normal operation and closing it with the back flow of the working medium in an emergency.

Devices of this type are used both in normal operation systems of power plants and as elements of safety systems, for example, to protect nuclear power plant steam generators along the secondary side.

When using reverse gates in normal operation systems, the rotary disc is normally open to allow the medium to pass through. In the event of an accident, the plate closes the shutter, preventing the reverse flow of the medium.

When using reverse gates as elements of safety systems, they separate circuits with different pressures during normal operation of the installation and report them when the differential pressure across the valve is equalized or specified. That is, in this case, the shutter plate is in the normally closed position.

Numerous improvements have been proposed for the currently known reverse gate designs, but some technical problems regarding their reliability, speed of operation, modes and duration of operation have remained unresolved.

This invention is directed to solving these problems.

As a prototype of the claimed invention, a reverse rotary valve OAO “ChZEM” is used in pipeline systems of nuclear power plants with VVER reactors [catalog of OAO ′ ′ CHZEM ”, TsNIITEITYAZHMASH, 1997, pp. 121-122]. This shutter has a housing with a lid and a rotary plate with a saddle mounted inside the housing, as well as a rod passing through the cover, pivotally connected to the plate.

This device has a number of disadvantages, in particular, passive triggering of the operation is possible with it only in one single case, when the direction of flow of the working medium changes. The device is not equipped with a system of autonomous operation of the plate for a given value of the pressure of the medium in the pipeline system, which significantly narrows the scope of the device in emergency situations and requires the installation of additional equipment. Another drawback is that the plate stock does not have a forced drive, which reduces the speed and reliability of the shutter. The lack of active fixation of the plate in the extreme opening and closing positions increases the likelihood of incomplete overlap of the passage section, as well as vibrational rattling of structural elements and their premature wear.

One way to improve the reliability of the reverse valves in security systems could be their backup duplication, that is, installation in pipelines of blocks of two adjacent identical valves. However, in relation to the known device under consideration, such a solution seems to be ineffective, since there arises the problem of the dependence of the gate operation on each other, in particular, an indefinite algorithm for their joint operation under emergency operating environment parameters.

The objective of the present invention is to expand the scope of the possible application of the reverse shutter, as well as improving technical and economic characteristics due to the increased level of safety, reliability and duration of operation.

The technical result achieved in the invention is that in the proposed device it is possible to pre-configure the operation of the rotary plate according to two reference values of the working medium pressure, and during its operation passive movement of the plate to the extreme opening and closing positions and its fixation in these positions is provided. That is, in comparison with the prototype, the reverse gate acquires additional operational qualities, since it becomes possible to regulate its response to changes in the characteristics of the working environment, including an autonomous passive response to an emergency situation, and, at the same time, its response speed, the contact density of the rotary plate with a saddle in the closed position, jamming and vibrational wear of structural elements is excluded. In addition, when duplicating, that is, when installing a block of two reverse gates in the pipeline system, you can control the algorithm for their joint operation, which was not available in the known device.

The technical result in the claimed invention is achieved due to the fact that there are two rod actuators in the backward swing shutter, comprising a body with a cover and a rotary plate with a seat installed inside the body, as well as a rod pivotally connected to the plate through the cover. Activation of the first of them - pneumatic - causes the plate to close. The second drive - spring - is installed for passive opening of the plate with an inactive pneumatic drive. In addition, a control system is connected to the pneumatic actuator, which activates it by supplying gas to it when the medium pressure inside the valve reaches the set closing value, and deactivates it by releasing gas from it when the medium pressure inside the valve reaches the set opening pressure.

According to the invention, a control system comprising a module for supplying gas to the pneumatic drive and a module for discharging gas from the drive can be used to activate the pneumatic drive. The gas supply module consists of a closing initiator and a two-position valve switched by it, connected to an autonomous high-pressure gas source on one side and to a pneumatic shutter drive on the other side. In this case, the closing initiator is adjusted to operate when the pressure of the medium in the shutter reaches a value equal to the closing pressure.

The gas release module also contains two elements - the initiator of the opening and the on-off valve switched by it, which is connected to the pneumatic actuator on one side and to the drainage (discharge of the high pressure control gas) on the other side. In this case, the opening initiator response is adjusted to the opening pressure value.

The initiators of opening and closing can be made pneumatic and have a message with the internal cavity of the shutter through the channels in its cover.

In accordance with the invention, initiators can be adjusted in various ways. In the embodiment, when the opening pressure is set lower than the closing pressure, when the pressure of the medium inside the valve increases, the actuation of the initiator of the opening closes the gas outlet, and the actuation of the initiator of closure opens the gas supply. In the embodiment, when the opening pressure is set higher than the closing pressure, when the pressure of the medium inside the valve increases, the actuation of the initiator of opening opens the gas outlet, and the actuation of the initiator of closure closes the gas supply.

In the case when a block of two reverse valves is used, at the valve located closer to the protected object, the reference values of the opening pressure are set higher and the closing pressure is lower than that of the second valve of this pair.

In addition, the shutter can be equipped with an additional manual actuator stem.

The invention is illustrated by drawings, where in FIG. 1 shows two options for its use - as part of the safety system of a power plant (A) and as an element of its normal operation (B). In FIG. 2 and FIG. 3, the butterfly valve is shown in the open and closed positions when it is used as part of a security system. In FIG. 4 and FIG. 5, a reversible butterfly valve is shown in the open and closed positions when it is used as part of a normal operation system.

The shutter comprises a housing 1 with a cover 2, a rotary plate 3 and a saddle 4 mounted inside the housing 1 (Fig. 2).

When the shutter is closed, the plate 3 completely covers the bore by tightly pressing against the seat 4, and when the shutter is open, it occupies its highest position, as shown in FIG. 2, to minimize hydraulic losses. The shutter itself is installed in such a way that the plate opens under the action of the flow of the working medium during normal operation of the installation and closes when the flow is reversed.

The shutter also has a rod 5 passing through the cover 2 and pivotally connected to the plate 3. The hinge can be made of a rotating shaft 6, a lever 7 and a connecting link 8.

The shutter is equipped with a spring actuator of the rod 9 and a pneumatic actuator 10. When the pneumatic actuator is activated, its pneumatic cylinder is filled with high pressure gas and the rod 5 under the action of the piston 11 forcibly fixes the plate 3 in the closed position (Fig. 3). When the pneumatic drive is inactive, the plate is passively transferred to the opening position and is forcedly fixed in this position under the influence of the spring drive 9 (Fig. 2).

The use of actuators of the spring and pneumatic type is dictated by considerations of safe and reliable operation of the shutter in harsh operating conditions of power plants, in particular nuclear power plants, and the need for autonomous passive shutter operation in an emergency. The same considerations determine the choice of the spring type of actuator specifically for passively initiating the opening of the shutter.

In the claimed invention, the activation and deactivation of a pneumatic actuator is carried out using a control system configured to two benchmark values of the pressure of the working medium inside the shutter. When the medium pressure reaches the preset closing value, the control system delivers gas to the pneumatic actuator, causing it to be activated. When the medium pressure reaches a predetermined opening value, the control system releases gas from the pneumatic actuator, causing it to deactivate. In this case, the closing pressure can be selected both large and lower than the opening pressure, thereby providing the necessary algorithm of operation for various versions of the use of the shutter.

To achieve greater autonomy and reliability of the shutter, it is preferable to use a pneumatic type control system. It has an autonomous source of high pressure gas 12, a module for supplying gas to the pneumatic actuator 13, a module for discharging gas from the actuator 14 to the drainage 15 (Fig. 2). Each module consists of two elements - a two-position valve and a trigger initiator, adjusted to switch the corresponding valve at a given value of the pressure of the medium in the gate.

The listed nodes communicate with each other through pipelines or channels, one of which connects the gas source 12 to the valve of the supply module 13, the other pipe connects the valve of the supply module 13 to the pneumatic actuator 10, the third pipeline connects the pneumatic actuator 10 to the valve of the gas exhaust module 14, and the fourth connects the valve of the gas discharge module 14 with drainage 15. In this case, the on-off valve of the supply module 13 is switched by the closing initiator 16 adjusted to the closing pressure, and the on-off valve of the exhaust module 14 switches initiated the opening 17 by adjusting the opening pressure.

In the embodiment of FIG. In an embodiment of the invention, the initiators of closing 16 and opening 17 are pneumatic and the shutter cover 2 has channels 18 communicating the inner cavity of the shutter with initiators. This solution is distinguished by the autonomy and reliability of the shutter and the simplicity of its assembly.

Pneumatic initiators and on-off valves used in the inventive valve are known devices commercially available from the industry. The ability to switch the valve inlet, that is, to interchange the pipelines connected to them, and to pre-configure the initiators for different pressure values significantly expands the scope of the valve. In FIG. 1 shows two possible uses.

When protecting the object 20 as part of the normal operation of the power plant (B), the shutter is in the normally open position and passively closes in an emergency when the pressure in the circuit drops to a predetermined closing reference value.

If the shutter is used as an element of the security system, then in the standby mode of operation at power, its passage section is closed, that is, the shutter is in the normally closed position. In the event of an emergency, the shutter opens passively when the pressure in the circuit decreases to the set opening value, connecting the hydraulic reservoir 21 to object 20 (A).

As an element of the security system of a power plant, the reverse gate operates as follows.

Before starting operation, the control system of the pneumatic drive is adjusted to the specified reference values of the opening and closing pressures. In this case, the value of the opening pressure by which the response of the initiator of opening is controlled should be less than the value of the closing pressure by which the response of the initiator of closure is adjusted.

Before the installation reaches power, the valve of the gas supply module 13 shuts off the power of the pneumatic actuator 10 and the rotary plate 3 under the action of the spring actuator 9 is in the open position of the shutter (Fig. 2).

In the process of the output of the power plant to power, the pressure of the medium inside the shutter gradually increases and reaches a predetermined opening value. In this case, the initiator of opening 17 is activated and the valve of the gas exhaust module 14 blocks the drainage 15. However, the pneumatic actuator remains inactive due to the blocked gas supply. Thus, the turntable continues to be in the open position.

With a further increase in pressure in the circuit, when the reference value of the closing pressure is reached, the closing initiator 16 is activated. The valve of the supply module 13 is switched to the gas injection position in the pneumatic actuator. The actuator activates and closes the shutter. This ensures that the plate is pressed against the saddle to prevent leakage.

During the subsequent regular operation of the installation at power, the reverse shutter will remain in standby mode with the plate closed (Fig. 3).

In the event of an emergency, a pressure drop in the installation circuit causes the closure initiator to react back, which shuts off the gas supply to the pneumatic actuator. In this case, the drive remains activated due to blocked drainage 15.

However, a further emergency decrease in pressure to a predetermined opening value will trigger the opening initiator, moving the valve of the gas release module and opening the drainage. The gas will be vented from the pneumatic actuator and the reverse shutter will open due to the passive action of the spring actuator 9.

The operation of the inverse shutter as an element of the normal operation system of a power plant takes place according to a different algorithm, since when operating at power in normal mode it must remain in the open position.

Before starting operation, the control system of the pneumatic drive is adjusted to the specified reference values of the opening and closing pressures. In this case, the value of the opening pressure by which the response of the initiator of opening is controlled should exceed the value of the closing pressure by which the actuation of the initiator of closing is set.

Before the power plant reaches its capacity, the pneumatic actuator of the plate rod is in the activated state, and the plate blocks the passage section of the shutter. This is achieved due to the fact that the on-off valve of the supply module of the control system is in the position of pumping gas into the pneumatic cylinder of the actuator, and the valve of the gas release module blocks the drainage pipe (Fig. 4).

In the process of the power plant reaching power, the pressure of the medium inside the shutter gradually increases and reaches a predetermined closing value. In this case, the closing initiator is triggered and the valve of the gas supply module shuts off the gas supply to the pneumatic actuator. However, the drive remains activated due to blocked drainage in the gas discharge module. Thus, the turntable continues to close the shutter.

With a further increase in pressure in the circuit, the set value of the opening pressure is reached and the opening initiator is triggered, causing the drainage to open in the gas discharge module. The gas is vented and the pneumatic actuator is deactivated, and the spring actuator opens the shutter and forcibly fixes the rotary disc in its highest position.

With further normal operation of the installation at power, the reverse shutter is in standby mode with an open plate and an inactive pneumatic actuator.

In the event of an emergency, a drop in pressure in the installation circuit will cause the initiator of the opening to react back, which will put the valve of the gas discharge module into the shut-off position of the drain. Further emergency pressure reduction will trigger the closing initiator and move the valve of the gas supply module. The pneumatic actuator is activated, and the shutter closes, forcing the plate against the seat.

As mentioned above, the reliability of the reverse valves in safety systems can be improved by duplicating them, that is, by installing blocks of two adjacent identical valves. In some cases, such backup duplication is a mandatory regulatory requirement, for example, in nuclear energy. An advantage of the claimed device is that it satisfies this requirement. The corresponding initiators of opening and closing the gates in the block can be adjusted to close, but not the same values of the pressure of the medium, as a result of which it becomes possible to pre-determine the sequence of operation of the gates in an emergency. For the proposed valves, their joint work in the block is a deterministic and controlled process, which is not achieved in the known solutions.

With reference to the two system variants shown in FIG. 1, the greatest positive effect from the use of shutter blocks is achieved if, when closing, the shutter of the block that is farthest in the direction of movement of the working medium is first closed, and after that the close shutter is triggered. And when opening, on the contrary, the closure of the block closest to the direction of movement of the working medium must first open. To do this, the shutter located closer to the protected object, the opening pressure must be set higher, and the closing pressure is lower than the second shutter of this pair.

The proposed reverse rotary valve can also be equipped with an additional manual actuator of the plate stem as a backup control.

Claims (7)

1. The backward swing valve, comprising a housing with a lid and a rotary disk with a saddle mounted inside the housing, as well as a rod passing through the lid, pivotally connected to the plate, characterized in that the valve is equipped with a pneumatic rod actuator for closing the plate and a spring rod actuator for it passive opening, and the pneumatic actuator is connected to a control system that activates it when the medium pressure inside the valve reaches the set closing value, and deactivates the pneumatic actuator when the pressure of the fluid within the valve reaches a predetermined opening pressure. 2. The shutter according to claim 1, characterized in that the control system comprises a module for supplying gas to the pneumatic actuator and a module for discharging gas from the actuator, the gas supply module consists of a closing initiator and a two-position valve switched by it connected to an autonomous gas source and a pneumatic actuator, and the gas release module consists of an initiator of opening and a two-position valve switched by it connected to a pneumatic actuator and drainage, and the initiator of closure is adjusted to the closing pressure, and the initiator is open tions adjusted to the opening pressure. 3. The shutter according to claim 2, characterized in that the actuation of the initiator of the opening is adjusted to close the gas outlet, and the actuation of the initiator of closure is adjusted to open the gas supply when the pressure of the medium inside the valve increases, if the opening pressure is set lower than the closing pressure. 4. The shutter according to claim 2, characterized in that the actuation of the initiator of the opening is adjusted to open the gas outlet, and the actuation of the initiator of closure is adjusted to shut off the gas supply when the pressure of the medium inside the valve increases, if the opening pressure is set higher than the closing pressure. 5. The shutter according to claim 3 or 4, characterized in that it is mounted in a pair, wherein the shutter located closer to the protected object has an opening pressure higher and a closing pressure lower than that of the other shutter of this pair. 6. The shutter according to claim 2, characterized in that the initiators of opening and closing are made pneumatic and connected to the inner cavity of the shutter through channels in its cover. 7. The shutter according to claim 1, characterized in that it is equipped with a manual rod actuator.

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