A control circuit and control method for a valve motor

Abstract

The present invention discloses a control circuit for a valve motor, wherein the control circuit includes a first relay 004XR, whose normally closed contact is connected in parallel with the normally closed contact of a thermal relay 001XS of a power circuit, and whose coil is connected in series with a first conductor of a detachable test button box. When the detachable test button box is inserted into the circuit, the coil of the first relay 004XR is energized, and its normally closed contact is disconnected, so as to activate the thermal overload protection of the valve motor. After the detachable test button box is pulled out of the circuit, the coil of the first relay 004XR loses power, and its normally closed contact is closed, so as to bypass the thermal overload protection of the valve motor. Accordingly, a control method for a valve motor is also provided. The control circuit can activate thermal overload protection for safety-level valves during regular or maintenance tests, thereby avoiding economic losses caused by overheating and burning, and ensuring that the safety function of the safety-level valve is prioritized during normal operation.

Description

Technical Field

[0001] The invention belongs to the field of nuclear power, and in particular relates to a control circuit and a control method for a valve motor. Background Art

[0002] High torque and high current may occur at one or some stages of the opening or closing stroke of the electric valve, which may cause the thermal overload protection of the valve motor to operate at an inappropriate time to protect the insulation of the motor or prevent overheating and burning. However, while protecting the motor, it may hinder the execution of the valve safety function (such as closing or opening the valve). For example, the motor of a safety-grade valve is cut off from power supply due to the overload protection action, making it impossible to perform the required safety function.

[0003] For safety-level valves that need to perform safety functions immediately after a baseline accident, the execution of safety functions is of primary importance. Therefore, the current design of valve motors includes: thermal overload protection is not designed for safety-level valves to ensure the execution of their safety functions, and thermal overload protection is designed for non-safety-level valves. However, valves are prone to thermal overload problems during regular or maintenance tests. There is an urgent need for a control circuit that can enable thermal overload protection when safety-level valves are in regular or maintenance tests to prevent the motor from overheating and burning when opening or closing the valve, causing economic losses, and exit thermal overload protection during normal operation to ensure that safety functions take priority. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a control circuit and control method for a valve motor in view of the above-mentioned deficiencies in the prior art, which can provide thermal overload protection for safety-grade valves during regular or maintenance tests, thereby avoiding economic losses caused by overheating and burning, and ensuring that the safety function of safety-grade valves is prioritized during normal operation.

[0005] In a first aspect, an embodiment of the present invention provides a control circuit of a valve motor, including a power circuit and a control circuit.

[0006] The control circuit includes a control power supply, a first relay 004XR, a detachable test button box, a first control unit, a remote control valve opening unit, a remote control valve closing unit, a valve stroke and / or torque switch, and a valve opening auxiliary relay 001XO and a valve closing auxiliary relay 001XF. The detachable test button box includes a first conductor, a valve opening button, and a valve closing button. The normally closed contact of the first relay 004XR is connected in parallel with the normally closed contact of the thermal relay 001XS of the power circuit, and then connected in series with the first control unit to form a first branch. The coil of the first relay 004XR is connected in series with the first conductor of the detachable test button box to form a second branch. The valve opening button of the detachable test button box is connected in parallel with the remote control valve opening unit, and then connected in series with the valve stroke and / or torque switch and the coil of the valve opening auxiliary relay 001XO to form a third branch. After the valve closing button of the detachable test button box is connected in parallel with the remote control valve closing unit, it is connected in series with the valve travel and / or torque switch and the coil of the valve closing auxiliary relay 001XF to form the fourth branch. Among them, the first branch, the second branch, the third branch, and the fourth branch are connected in parallel and then connected to the control power supply.

[0007] When the detachable test button box is inserted into the circuit, the coil of the first relay 004XR is energized and the normally closed contacts of the first relay 004XR are opened to activate the thermal overload protection of the valve motor. After the detachable test button box is unplugged from the circuit, the coil of the first relay 004XR is de-energized and the normally closed contacts of the first relay 004XR are closed to bypass the thermal overload protection of the valve motor.

[0008] Preferably, the first branch further includes a connecting piece 004JS. The connecting piece 004JS is connected in series with the normally closed contact of the first relay 004XR, and then connected in parallel with the normally closed contact of the thermal relay 001XS.

[0009] Preferably, the first control unit includes a fifth branch and a sixth branch connected in parallel. The fifth branch includes the normally open contact of the valve opening auxiliary relay 001XO, the normally closed contact of the valve closing contactor 002JA, and the coil of the valve opening contactor 001JA, which are connected in series in sequence. The sixth branch includes the normally open contact of the valve closing auxiliary relay 001XF, the normally closed contact of the valve opening contactor 001JA, and the coil of the valve closing contactor 002JA, which are connected in series in sequence.

[0010] Preferably, the remote control valve opening unit includes the normally open contact of the remote control valve opening relay 001XR, the normally closed contact of the remote control valve closing relay 002XR, and the normally open contact of the valve opening contactor 001JA. The normally open contact of the remote control valve opening relay 001XR is connected in parallel with the normally open contact of the valve opening contactor 001JA, and then connected in series with the normally closed contact of the remote control valve closing relay 002XR.

[0011] The remote control valve closing unit includes the normally closed contact of the remote control valve opening relay 001XR, the normally open contact of the remote control valve closing relay 002XR, and the normally open contact of the valve closing contactor 002JA. The normally open contact of the remote control valve closing relay 002XR is connected in parallel with the normally open contact of the valve closing contactor 002JA, and then connected in series with the normally closed contact of the remote control valve opening relay 001XR.

[0012] Preferably, the power circuit includes a power supply, a valve opening contactor 001JA, a valve closing contactor 002JA, and a thermal relay 001XS. After the main contact of the valve opening contactor 001JA is connected in parallel with the main contact of the valve closing contactor 002JA, its inlet end is connected to the power supply, and its outlet end is connected in series with the coil of the thermal relay 001XS and the valve motor.

[0013] In a second aspect, an embodiment of the present invention further provides a method for controlling a valve motor, wherein the valve motor adopts the control circuit of the valve motor described in the first aspect; the method comprises: inserting a removable test button box into the control circuit to activate the thermal overload protection of the valve motor, or removing the removable test button box from the control circuit to bypass the thermal overload protection of the valve motor.

[0014] Preferably, using the control circuit of the valve motor described in the first aspect, after pulling out the detachable test button box, the method also includes: controlling the connecting piece 004JS to be in an on state to bypass the thermal overload protection of the valve motor; or controlling the connecting piece 004JS to be in an off state to activate the thermal overload protection of the valve motor.

[0015] The control circuit and control method of the valve motor of the present invention are that the normally closed contact of the first relay 004XR is connected in parallel with the normally closed contact of the thermal relay, and its coil is connected to the detachable test button box. After the detachable test button box is inserted, the coil of the first relay 004XR is energized, and the normally closed contact is disconnected, so as to be used for the thermal overload protection of the valve motor, and after the detachable test button box is pulled out, the coil of the first relay 004XR is de-energized, and the normally closed contact is closed, so as to bypass the thermal overload protection of the valve motor. Thus, the safety-level valve has the thermal overload protection function during the test, and during normal operation, the thermal overload protection function is bypassed (exited) to ensure that the safety function takes priority. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : is a schematic diagram of the control circuit of the valve motor of Example 1 of the present invention.

[0017] In the figure: 001JA-valve opening contactor; 002JA-valve closing contactor; 001XS-thermal relay; 001XO-valve opening auxiliary relay; 001XF-valve closing auxiliary relay; 001XR-auxiliary contact of remote control valve opening relay; 002XR-auxiliary contact of remote control valve closing relay;

[0018] 002PJ-detachable test button box; 001JS-isolator; MOV-valve motor;

[0019] 004XR-first relay; 004JS-connecting piece. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0021] Embodiment 1:

[0022] The electric valves in nuclear power plants are equipped with local control and remote control. During normal operation, the valves work in remote control mode. During maintenance, commissioning, testing or certain extreme conditions, local control can be achieved by inserting a detachable test button box 002PJ into the control circuit.

[0023] like Figure 1 As shown, this embodiment provides a control circuit of a valve motor, including a power circuit and a control circuit. It should be noted that since the control circuit of this embodiment is mainly used in the local control mode, Figure 1 The remote control loop structure is not shown completely.

[0024] The control circuit includes a control power supply, a first relay 004XR, a detachable test button box, a first control unit, a remote valve opening unit, a remote valve closing unit, a valve travel and / or torque switch, and a valve opening auxiliary relay 001XO and a valve closing auxiliary relay 001XF.

[0025] Wherein, the detachable test button box 002PJ includes a first conductor, a valve opening button, and a valve closing button. After the normally closed contact of the first relay 004XR is connected in parallel with the normally closed contact of the thermal relay 001XS of the power circuit, it is connected in series with the first control unit to form a first branch. The coil of the first relay 004XR is connected in series with the first conductor of the detachable test button box 002PJ to form a second branch. After the valve opening button of the detachable test button box 002PJ is connected in parallel with the remote control valve opening unit, it is connected in series with the valve stroke and / or torque switch and the coil of the valve opening auxiliary relay 001XO to form a third branch. After the valve closing button of the detachable test button box 002PJ is connected in parallel with the remote control valve closing unit, it is connected in series with the valve stroke and / or torque switch and the coil of the valve closing auxiliary relay 001XF to form a fourth branch. Wherein, the first branch, the second branch, the third branch, and the fourth branch are connected in parallel and then connected to the control power supply. The first relay 004XR can use a conventional auxiliary relay, such as Izumi's RH3B series relay.

[0026] When the detachable test button box 002PJ is inserted into the control circuit, the coil of the first relay 004XR is energized and the normally closed contact of the first relay 004XR is disconnected, so as to activate the thermal overload protection of the valve motor. That is, when the valve motor is thermally overloaded during operation, the normally closed contact of the thermal overload relay 001XS is disconnected, the coil of the valve opening contactor or the coil of the valve closing contactor loses power, and the main contacts of the valve opening contactor or the main contacts of the valve closing contactor are disconnected, so that the valve motor stops running due to power loss, and the valve motor is protected from thermal overload. After the detachable test button box 002PJ is pulled out from the control circuit, the coil of the first relay 004XR loses power, and the normally closed contact of the first relay 004XR is closed, so as to bypass (exit) the thermal overload protection of the valve motor, that is, when the valve motor is thermally overloaded during operation, the normally closed contact of the thermal overload relay 001XS is disconnected. Since the normally closed contact of the first relay 004XR is closed, the normally closed contact of the thermal overload relay 001XS is in a closed or disconnected state, and cannot act on the main contact of the valve opening contactor or the main contact of the valve closing contactor, so the valve motor has no thermal overload protection. Therefore, by setting the first relay 004XR and connecting it in parallel with the normally closed contact of the thermal relay, the bypass control of the thermal overload protection of the valve motor is realized, and the thermal overload protection can be put into use for the safety-level valves of the nuclear power plant during regular or maintenance tests, thereby avoiding economic losses caused by overheating and burning, and ensuring that the safety function of the safety-level valves is prioritized during normal operation, thereby ensuring the safety of the nuclear power plant.

[0027] Optionally, the first branch further includes a connecting piece 004JS. The connecting piece 004JS is connected in series with the normally closed contact of the first relay 004XR, and then connected in parallel with the normally closed contact of the thermal relay 001XS.

[0028] In this embodiment, a connecting piece 004JS is set in the first branch to be connected in series with the normally closed contact of the first relay 004XR to realize the standardized design of the control circuit of the safety-level valve and the non-safety-level valve. For example, after the detachable test button box 002PJ is inserted, no matter whether the connecting piece 004JS is in the on or off state, the thermal overload protection is put into use, so that the safety-level valve and the non-safety-level valve have the thermal overload protection function during regular or maintenance tests. After the detachable test button box 002PJ is pulled out, for the safety-level valve, the connecting piece 004JS needs to be set in the on state so that the safety-level valve bypasses the thermal overload protection during normal operation to ensure the primary position of the safety function; for the non-safety-level valve, since there is no immediate safety function requirement after an accident, the connecting piece 004JS needs to be set in the off state so that the non-safety-level valve has the thermal overload protection function during normal operation. The connecting piece 004JS can adopt the STL5 series control terminal of Weidmuller. Since there are a large number of electric valves in nuclear power plants, the control circuit of the valve motor in this embodiment is promoted and applied, which has the promotion value of simple structure, small scope of modification and controllable cost.

[0029] Preferably, the first control unit includes a fifth branch and a sixth branch connected in parallel. The fifth branch includes the normally open contact of the valve opening auxiliary relay 001XO, the normally closed contact of the valve closing contactor 002JA, and the coil of the valve opening contactor 001JA, which are connected in series in sequence. The sixth branch includes the normally open contact of the valve closing auxiliary relay 001XF, the normally closed contact of the valve opening contactor 001JA, and the coil of the valve closing contactor 002JA, which are connected in series in sequence.

[0030] Preferably, the remote control valve opening unit includes the normally open contact of the remote control valve opening relay 001XR, the normally closed contact of the remote control valve closing relay 002XR, and the normally open contact of the valve opening contactor 001JA. The remote control valve opening unit is used to perform corresponding actions according to the valve opening command of the remote control, wherein the normally open contact of the remote control valve opening relay 001XR is connected in parallel with the normally open contact of the valve opening contactor 001JA, and then connected in series with the normally closed contact of the remote control valve closing relay 002XR.

[0031] The remote control valve closing unit includes the normally closed contact of the remote control valve opening relay 001XR, the normally open contact of the remote control valve closing relay 002XR, and the normally open contact of the valve closing contactor 002JA. The remote control valve closing unit is used to perform corresponding actions according to the valve closing command of the remote control, wherein the normally open contact of the remote control valve closing relay 002XR is connected in parallel with the normally open contact of the valve closing contactor 002JA, and then connected in series with the normally closed contact of the remote control valve opening relay 001XR.

[0032] Preferably, the power circuit includes a power supply, a valve opening contactor 001JA, a valve closing contactor 002JA, and a thermal relay 001XS. After the main contact of the valve opening contactor 001JA is connected in parallel with the main contact of the valve closing contactor 002JA, its inlet end is connected to the power supply, and its outlet end is connected in series with the coil of the thermal relay 001XS and the valve motor. The valve motor is driven by an AC power supply or a DC power supply.

[0033] Working principle of the control circuit of the valve motor:

[0034] (1) Insert the detachable test button box 002PJ and press the valve opening button: the coil of the first relay 004XR connected in series with the first conductor is energized, and the normally closed contact of the first relay 004XR in the first branch is disconnected. The valve travel and / or torque switch connected in series with the valve opening button is turned on, the coil of the valve opening auxiliary relay 001XO in the third branch is energized, the normally open contact of the valve opening auxiliary relay 001XO in the fifth branch is closed, the coil of the valve opening contactor 001JA is energized, the main contact of the valve opening contactor 001JA in the power circuit is closed, and the valve motor runs to realize the valve opening action. When the valve motor is running and thermal overload occurs, the thermal overload relay 001XS is activated, and the normally closed contact of the thermal overload relay 001XS in the first branch is disconnected. Since the normally closed contact of the first relay 004XR connected in parallel is also in the disconnected state, the coil of the valve opening contactor 001JA in the fifth branch loses power, and the main contact of the valve opening contactor 001JA in the power circuit is disconnected, and the valve motor loses power and stops running, so the valve motor is protected from thermal overload. When the detachable test button box 002PJ is inserted and the valve closing button is pressed, the working principle of the control circuit is similar and will not be repeated here. Therefore, when the valve is regularly or undergoing maintenance tests and debugging, the detachable test button box 002PJ is inserted to activate thermal overload protection. It should be noted that after the detachable test button box 002PJ is inserted, for safety-grade valves or non-safety-grade valves, the state of the connecting piece 004JS will not affect the activation of thermal overload protection.

[0035] (2) Pull out the detachable test button box 002PJ (i.e., in remote control mode), and remotely control the valve opening: the first conductor is pulled out, the coil of the first relay 004XR connected in series with it loses power, and the normally closed contact of the first relay 004XR in the first branch is closed. The normally open contact of the remote valve opening relay 001XR in the remote valve opening unit is closed, and the normally closed contact of the remote valve opening relay 001XR in the remote valve closing unit is disconnected. Since the normally closed contact of the remote valve closing relay 002XR is in a closed state, the valve travel and / or torque switch connected to the remote valve opening unit is turned on, the coil of the valve opening auxiliary relay 001XO in the third branch is energized, the normally open contact of the valve opening auxiliary relay 001XO in the fifth branch is closed, the coil of the valve opening contactor 001JA is energized, the main contact of the valve opening contactor 001JA in the power circuit is closed, and the valve motor runs to realize the valve opening action. Since the normally closed contact of the first relay 004XR is in the closed state, the state (closed or open) of the normally closed contact of the thermal relay 001XS cannot act on the main contact of the valve opening contactor 001JA or the main contact of the valve closing contactor 002JA, thereby bypassing (exiting) the thermal overload protection. Pulling out the detachable test button box 002PJ and remotely controlling the valve closing is similar in principle and will not be repeated here.

[0036] (3) For safety-level valves, after the detachable test button box 002PJ is pulled out (i.e., in remote control mode), the connecting piece 004JS should be in the on state to bypass the thermal overload protection of the valve motor, so that the safety-level valve can ensure the safety function first during normal operation. Its working principle will not be described in detail here; for non-safety-level valves, since they do not need to perform safety functions, the connecting piece 004JS should be in the off state to activate the thermal overload protection of the valve motor. Its working principle will not be described in detail here.

[0037] The control circuit of the valve motor of this embodiment introduces the first relay 004XR normally closed contact in parallel with the normally closed contact of the thermal relay 001XS, and sets the first conductor in the detachable test button box 002PJ, so that when the detachable test button box 002PJ is inserted into the control circuit, its first conductor is connected in series with the coil of the first relay 004XR, thereby realizing the automatic bypass thermal overload protection of the safety-level valve, solving the requirement of the safety-level valve motor MOV for automatic bypass thermal overload protection in the event of an accident, and meeting the nuclear safety requirements for the valve motor MOV thermal overload protection configuration. Secondly, by introducing the connecting piece 004JS in series with the normally closed contact of the first relay 004XR, the function of automatically bypassing the thermal overload can be selected to be put into and out of the automatic bypass thermal overload function, and the control circuit of the non-safety-level valve can also be adopted, which is used for the standardization of the control circuit of the valve motor. In addition, the changes to the control circuit of the existing valve motor MOV are very small, only two sets of simple components are added (the first relay 004XR and the connecting piece 004JS). The design is simple and the investment cost is low. Since there are a large number of valves in nuclear power plants, the control circuit can be widely promoted in nuclear power plants and has high economic value.

[0038] Embodiment 2:

[0039] This embodiment provides a control method for a valve motor, wherein the valve motor adopts the control circuit of the valve motor described in Embodiment 1; the method comprises:

[0040] Insert a detachable test button box 002PJ into the control circuit to activate the thermal overload protection of the valve motor, or remove the detachable test button box 002PJ from the control circuit to bypass the thermal overload protection of the valve motor.

[0041] Optionally, using the control circuit of the valve motor including the connecting piece 004JS in Example 1, after the detachable test button box is pulled out, the method further includes:

[0042] The control connecting piece 004JS is in the on state to bypass the thermal overload protection of the valve motor; or the control connecting piece 004JS is in the off state to activate the thermal overload protection of the valve motor.

[0043] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A control circuit of a valve motor, comprising a power circuit and a control circuit, characterized in that: The control circuit includes a control power supply, a first relay 004XR, a detachable test button box, a first control unit, a remote valve opening unit, a remote valve closing unit, a valve travel and / or torque switch, and a valve opening auxiliary relay 001XO and a valve closing auxiliary relay 001XF. The detachable test button box includes a first conductor, a valve opening button, and a valve closing button. The normally closed contact of the first relay 004XR is connected in parallel with the normally closed contact of the thermal relay 001XS of the power circuit, and then connected in series with the first control unit to form a first branch. The coil of the first relay 004XR is connected in series with the first conductor of the detachable test button box to form a second branch. After the valve opening button of the detachable test button box is connected in parallel with the remote control valve opening unit, it is then connected in series with the valve travel and / or torque switch and the coil of the valve opening auxiliary relay 001XO to form the third branch. After the valve closing button of the detachable test button box is connected in parallel with the remote control valve closing unit, it is then connected in series with the valve travel and / or torque switch and the coil of the valve closing auxiliary relay 001XF to form the fourth branch. Among them, the first branch, the second branch, the third branch, and the fourth branch are connected in parallel and then connected to the control power supply. When the detachable test button box is inserted into the circuit, the coil of the first relay 004XR is energized and the normally closed contacts of the first relay 004XR are opened to activate the thermal overload protection of the valve motor. After the detachable test button box is unplugged from the circuit, the coil of the first relay 004XR is de-energized and the normally closed contacts of the first relay 004XR are closed to bypass the thermal overload protection of the valve motor.

2. The control circuit of the valve motor according to claim 1, characterized in that: The first branch also includes a connecting piece 004JS, The connecting piece 004JS is connected in series with the normally closed contact of the first relay 004XR, and then connected in parallel with the normally closed contact of the thermal relay 001XS.

3. The control circuit of the valve motor according to claim 2, characterized in that: The first control unit includes a fifth branch and a sixth branch connected in parallel, The fifth branch includes the normally open contact of the valve opening auxiliary relay 001XO, the normally closed contact of the valve closing contactor 002JA, and the coil of the valve opening contactor 001JA, which are connected in series in sequence. The sixth branch includes the normally open contact of the valve closing auxiliary relay 001XF, the normally closed contact of the valve opening contactor 001JA, and the coil of the valve closing contactor 002JA, which are connected in series in sequence.

4. The control circuit of the valve motor according to claim 3, characterized in that: The remote control valve opening unit includes the normally open contact of the remote control valve opening relay 001XR, the normally closed contact of the remote control valve closing relay 002XR, and the normally open contact of the valve opening contactor 001JA. The normally open contact of the remote control valve opening relay 001XR is connected in parallel with the normally open contact of the valve opening contactor 001JA, and then connected in series with the normally closed contact of the remote control valve closing relay 002XR. The remote control valve closing unit includes the normally closed contact of the remote control valve opening relay 001XR, the normally open contact of the remote control valve closing relay 002XR, and the normally open contact of the valve closing contactor 002JA. The normally open contact of the remote control valve closing relay 002XR is connected in parallel with the normally open contact of the valve closing contactor 002JA, and then connected in series with the normally closed contact of the remote control valve opening relay 001XR.

5. The control circuit of the valve motor according to claim 4, characterized in that: The power circuit includes power supply, valve opening contactor 001JA, valve closing contactor 002JA, thermal relay 001XS, After the main contacts of the valve opening contactor 001JA and the valve closing contactor 002JA are connected in parallel, the incoming line end is connected to the power supply, and the outgoing line end is connected in series with the coil of the thermal relay 001XS and the valve motor.

6. A control method for a valve motor, characterized in that: The valve motor adopts the control circuit of the valve motor according to any one of claims 1 to 5; the method comprises: Insert a removable test button box into the control circuit to activate the thermal overload protection of the valve motor. Alternatively, a removable test button box is unplugged in the control circuit to bypass the thermal overload protection of the valve motor.

7. The control method of the valve motor according to claim 6, characterized in that: A control circuit for a valve motor according to any one of claims 2 to 5 is used, After pulling out the detachable test button box, the method further includes: The control connecting piece 004JS is in the conducting state to bypass the thermal overload protection of the valve motor; Or control the connecting piece 004JS to be in the disconnected state to activate the thermal overload protection of the valve motor.

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