Safety protection circuit and intermittent working equipment
By designing a safety protection circuit including automatic start-stop, abnormal flow cut-off control and other units, the problem of continuous operation of the equipment under air suction and interruption, abnormal stagnation, etc., is solved, and the safety protection and operation reliability of the equipment are achieved.
Patent Information
- Application Number
- CN202421681913.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-16
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-07-16
AI Technical Summary
When existing equipment encounters air suction and discharging, abnormal stagnation, etc., it will continue to operate, resulting in heat generation of the pump body, leakage of mechanical seals, reduced working efficiency, and may even cause fires, increasing maintenance costs and affecting the normal operation of related equipment.
A safety protection circuit is designed, including an automatic start-stop and flow abnormal shutdown control unit, a start-stop contactor and an operation indicator circuit unit, a flow switch and a delay control unit, a flow abnormal delay shutdown control unit and a flow abnormal reset control unit. Through the coordinated work of these units, the power supply can be cut off in time when abnormalities occur in the equipment to prevent overheating and damage from the equipment.
Effectively prevent equipment from overheating and damage in abnormal situations, reduce maintenance costs, improve equipment operation safety and reliability, and ensure the normal operation of related equipment.
Smart Images
Figure CN222981233U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the technical field of circuit design, and relates to a protection circuit, in particular to a safety protection circuit and an intermittent working device. Background Art
[0002] Many devices need to work intermittently in daily work. If abnormal device conditions, conventional security failures, or abnormal working environments occur, the device operation time may exceed the designed working conditions, causing device damage, increasing device maintenance costs, and affecting the normal operation of associated devices. Although many current devices are equipped with some safety protection devices such as overload and high-temperature protection measures, there are still situations where protection is not timely for some emergencies, and the device works "with problems" beyond the normal working conditions. Taking the marine domestic fresh water pump device as an example, the domestic fresh water pump is powered by connecting to the power supply through the switch of the operation control contactor. The operation control contactor forms a series circuit with the normally closed high-voltage switch of the operation control pressure relay, the normally open low-voltage switch of the operation control pressure relay, and the parallel circuit of the normally open switch of the operation control contactor, and is connected to the positive and negative poles of the power supply. The power supply of the domestic fresh water pump is controlled by the on-off of the operation controller, thereby controlling the automatic start and stop.
[0003] When the domestic fresh water pump has situations such as suction air break and abnormal stagnant flow, the pump will continue to operate. These abnormal working conditions will cause the pump body to heat up, mechanical seal leakage, and reduced working efficiency. In severe cases, it will cause the pump to overheat and damage or even cause a fire. Many ships use domestic fresh water pumps to supply domestic water and boiler feed water. Once the pump is damaged, it will also affect the domestic water supply of the crew and the operation safety of the ship's boiler. Summary of the Utility Model
[0004] This application provides a safety protection circuit and an intermittent working device, which are used to solve the safety protection problem of intermittent working devices.
[0005] In a first aspect, this application provides a safety protection circuit, which includes: an automatic start-stop and flow anomaly cut-off control unit; a start-stop contactor and an operation indication circuit unit, which are connected to the automatic start-stop and flow anomaly cut-off control unit through a thermal protection relay to form a start-stop operation branch; a flow switch and its delay control unit, which is connected in parallel with the start-stop operation branch; a flow anomaly delay cut-off control unit, which is connected in parallel with the start-stop operation branch; a flow anomaly reset control unit, which is connected in parallel with the start-stop operation branch.
[0006] In an implementation of the first aspect, the automatic start-stop and abnormal flow cut-off control unit includes: a normally closed switch of a double-coil intermediate relay, a normally closed high-pressure switch of an operation control pressure relay, a normally open low-pressure switch of the operation control pressure relay, and a normally open switch of an operation control contactor; the normally closed switch of the double-coil intermediate relay, the normally closed high-pressure switch of the operation control pressure relay, and the normally open low-pressure switch of the operation control pressure relay are connected in series in sequence, and the normally open switch of the operation control contactor is connected in parallel with the normally open low-pressure switch of the operation control pressure relay.
[0007] In an implementation of the first aspect, the start-stop contactor and operation indication circuit unit includes: an operation control contactor and an operation indicator light; the operation control contactor and the operation indicator light are connected in parallel.
[0008] In an implementation of the first aspect, the flow switch and its delay control unit includes: a flow switch, a normally open switch of an operation control contactor, and a delay relay; the flow switch is connected in series with the normally open switch of the operation control contactor and the delay relay.
[0009] In an implementation of the first aspect, the abnormal flow delay cut-off control unit includes: a delay closing switch of the delay relay and a working coil of the double-coil intermediate relay; the delay closing switch of the delay relay is connected in series with the working coil of the double-coil intermediate relay.
[0010] In an implementation of the first aspect, the abnormal flow reset control unit includes: a reset button and a reset coil of the double-coil intermediate relay; the reset button and the reset coil of the double-coil intermediate relay are connected in series.
[0011] In an implementation of the first aspect, the normally open switch of the double-coil intermediate relay is connected to the engine room alarm circuit.
[0012] In a second aspect, the present application provides an intermittent working device, and the intermittent working device includes: an operation control circuit and the safety protection circuit connected to the operation control circuit.
[0013] In an implementation of the second aspect, the intermittent working device includes an engine room alarm circuit, and the normally open switch of the double-coil intermediate relay is connected to the engine room alarm circuit.
[0014] In an implementation of the second aspect, the intermittent working device includes a liquid delivery intermittent working device.
[0015] As described above, the safety protection circuit and the intermittent working device of the present application have the following beneficial effects:
[0016] By adding a double-coil intermediate relay K1, a flow switch S4, and a time-delay relay KT1 to the original operation control circuit, when the intermittent working device is in the automatic working mode and the input liquid is sucked empty or stagnant, the flow switch S4 remains closed, the protection delay relay KT1 acts, its delay-closed switch KT1 closes, the working coil of the double-coil intermediate relay K1 is energized, and the normally closed switch K1-1 of the double-coil intermediate relay K1 disconnects and locks, so that the operation control contactor KM1 is de-energized and the intermittent working device stops running. After troubleshooting, press the S5 reset button, the reset coil of the double-coil intermediate relay K1 is energized, the double-coil intermediate relay K1 resets, its normally closed switch K1-1 closes, and the device resumes normal use. The safety protection circuit of the present application has a simple structure. When the device sucks empty or stagnates the transported liquid, it will be protected and stopped. The work is effective and reliable, and it can protect the safe operation of the device more efficiently with a low-cost investment. Description of the Drawings
[0017] Figure 1 It shows a schematic structural diagram of the safety protection circuit described in the embodiment of the present application.
[0018] Figure 2 It shows a circuit diagram of the automatic start-stop and flow anomaly cut-off control unit of the safety protection circuit described in the embodiment of the present application.
[0019] Figure 3 It shows a circuit diagram of the start-stop contactor and operation indication circuit unit of the safety protection circuit described in the embodiment of the present application.
[0020] Figure 4 It shows a circuit diagram of the flow switch and its time-delay control unit of the safety protection circuit described in the embodiment of the present application.
[0021] Figure 5 It shows a circuit diagram of the flow anomaly time-delay cut-off control unit of the safety protection circuit described in the embodiment of the present application.
[0022] Figure 6 It shows a circuit diagram of the flow anomaly reset control unit of the safety protection circuit described in the embodiment of the present application.
[0023] Figure 7 It shows a circuit structure diagram of the safety protection circuit described in the embodiment of the present application.
[0024] Description of Component Labels
[0025] 1 Automatic start-stop and flow anomaly cut-off control unit
[0026] 2 Start-stop contactor and operation indication circuit unit
[0027] 3 Flow switch and its time-delay control unit
[0028] 4 Flow Abnormality Delay Cut-off Control Unit
[0029] 5 Flow Abnormality Reset Control Unit Detailed Implementation Manner
[0030] The following uses specific specific examples to illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.
[0031] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. Therefore, only the components related to the present application are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.
[0032] Next, the technical solutions in the embodiments of the present application will be described in detail with reference to the accompanying drawings in the embodiments of the present application.
[0033] Please refer to Figure 1 , which shows a schematic structural diagram of the safety protection circuit described in the embodiment of the present application. As Figure 1 shown, this embodiment provides a safety protection circuit, which can be set in the operation control circuit of an intermittent liquid delivery device, and specifically includes: an automatic start-stop and flow abnormality cut-off control unit 1, a start-stop contactor and operation indication circuit unit 2, a flow switch and its delay control unit 3, a flow abnormality delay cut-off control unit 4, and a flow abnormality reset control unit 5.
[0034] The start-stop contactor and operation indication circuit unit 2 is connected to the automatic start-stop and flow abnormality cut-off control unit 1 through a thermal protection relay to form a start-stop operation branch.
[0035] The flow switch and its delay control unit 3 are connected in parallel with the start-stop operation branch.
[0036] The flow abnormality delay cut-off control unit 4 is connected in parallel with the start-stop operation branch.
[0037] The flow abnormality reset control unit 5 is connected in parallel with the start-stop operation branch.
[0038] In one embodiment, the automatic start-stop and flow anomaly cut-off control unit 1 includes: the normally-closed switch of a double-coil intermediate relay, the normally-closed high-pressure switch of an operation control pressure relay, the normally-open low-pressure switch of the operation control pressure relay, and the normally-open switch of an operation control contactor.
[0039] The normally-closed switch of the double-coil intermediate relay, the normally-closed high-pressure switch of the operation control pressure relay, and the normally-open low-pressure switch of the operation control pressure relay are connected in series in sequence, and the normally-open switch of the operation control contactor is connected in parallel with the normally-closed high-pressure switch of the operation control pressure relay.
[0040] Please refer to Figure 2 , which shows the circuit diagram of the automatic start-stop and flow anomaly cut-off control unit of the safety protection circuit described in the embodiment of the present application. As Figure 2 shown, the automatic start-stop and flow anomaly cut-off control unit 1 includes: the normally-closed switch K1-1 of a double-coil intermediate relay K1, the normally-closed high-pressure switch S3 of an operation control pressure relay, the normally-open low-pressure switch S2 of the operation control pressure relay, and the normally-open switch KM1-1 of an operation control contactor KM1.
[0041] The normally-closed switch K1-1 of the double-coil intermediate relay K1, the normally-closed high-pressure switch S3 of the operation control pressure relay, and the normally-open low-pressure switch S2 of the operation control pressure relay are connected in series in sequence, and the normally-open switch KM1-1 of the operation control contactor KM1 is connected in parallel with the normally-open low-pressure switch S2 of the operation control pressure relay.
[0042] In one embodiment, the start-stop contactor and operation indication circuit unit includes: an operation control contactor and an operation indicator light.
[0043] The operation control contactor and the operation indicator light are connected in parallel.
[0044] Please refer to Figure 3 , which shows the circuit diagram of the start-stop contactor and operation indication circuit unit of the safety protection circuit described in the embodiment of the present application. As Figure 3 shown, the start-stop contactor and operation indication circuit unit includes: an operation control contactor KM1 and an operation indicator light H2. The operation control contactor KM1 and the operation indicator light H2 are connected in parallel.
[0045] In one embodiment, the flow switch and its delay control unit includes: a flow switch, the normally-open switch of an operation control contactor, and a delay relay.
[0046] The flow switch is connected in series with the normally-open switch of the operation control contactor and the delay relay.
[0047] Please refer toFigure 4 , showing the circuit diagram of the flow switch and its delay control unit of the safety protection circuit described in the embodiment of the present application. As Figure 4 shown, the flow switch and its delay control unit include: a flow switch S4, a normally open switch KM1-2 of an operation control contactor KM1, and a time-delay relay KT1. The flow switch S4 is connected in series with the normally open switch KM1-2 of the operation control contactor KM1 and the time-delay relay KT1.
[0048] In one embodiment, the flow anomaly delay cut-off control unit includes: a delay closing switch of the time-delay relay and a working coil of the double-coil intermediate relay.
[0049] The delay closing switch of the time-delay relay is connected in series with the working coil of the double-coil intermediate relay.
[0050] Please refer to Figure 5 , showing the circuit diagram of the flow anomaly delay cut-off control unit of the safety protection circuit described in the embodiment of the present application. As Figure 5 shown, the flow anomaly delay cut-off control unit includes: a delay closing switch KT1 of the time-delay relay KT1 and a working coil of the double-coil intermediate relay K1. The delay closing switch KT1 of the time-delay relay KT1 is connected in series with the working coil of the double-coil intermediate relay K1.
[0051] In one embodiment, the flow anomaly reset control unit includes: a reset button and a reset coil of the double-coil intermediate relay.
[0052] The reset button and the reset coil of the double-coil intermediate relay are connected in series.
[0053] Please refer to Figure 6 , showing the circuit diagram of the flow anomaly reset control unit of the safety protection circuit described in the embodiment of the present application. As Figure 6 shown, the flow anomaly reset control unit includes: a reset button S5 and a reset coil of the double-coil intermediate relay K1. The reset button S5 and the reset coil of the double-coil intermediate relay K1 are connected in series.
[0054] In one embodiment, the normally open switch of the double-coil intermediate relay is connected to the engine room alarm circuit.
[0055] Combined with Figures 1 to 6, the working principle of the safety protection circuit of this application is as follows: Taking the daily fresh water pump M, which is an intermittent working device where the safety protection circuit is located, as an example, when the liquid being transported is sucked empty or stagnant during the automatic operation of the daily fresh water pump M, the flow switch S4 at the pump outlet is in a closed state, and the time-delay relay KT1 is energized. When the set time of the time-delay relay KT1 is exceeded, the time-delay closed switch KT1 of the time-delay relay KT1 closes, and the double-coil intermediate relay K1 operates. Its normally closed switch K1-1 disconnects, thereby de-energizing the operation control contactor KM1, its switch KM1 disconnects, and the motor M stops running, playing a safety protection role. For the safety protection circuit of this application, only a protection double-coil intermediate contactor K1, a flow switch S4, a time-delay relay KT1, and some connecting wires need to be added to the original operation control circuit. The structure is simple. When the equipment stops flowing or stagnates during liquid transportation and operates for more than the set operation time, it is protected and stopped. The work is effective and reliable, and it can protect the safe operation of the equipment more efficiently with a low-cost investment.
[0056] In this embodiment, a double-coil intermediate relay K1 is used. When the time-delay closed switch of the time-delay relay KT1 closes, the double-coil intermediate relay K1 is energized, its normally closed switch K1-1 disconnects and locks, and the operation control contactor KM1 remains de-energized. To make the motor M run again, the reset button S5 needs to be pressed to energize and reset the reset coil of the double-coil intermediate relay K1, so as to keep the double-coil intermediate relay K1 locked.
[0057] When the operation control circuit of the intermittent working device further includes an engine room alarm circuit, the normally open switch K1-2 of the double-coil intermediate relay K1 is also connected to the engine room alarm circuit, and the action of the protection contactor triggers an alarm signal to remind the duty personnel to pay attention.
[0058] As Figure 3 shown, the operation control circuit of the daily fresh water pump M further includes an operation indicator light H2 connected in parallel with the operation control contactor KM1, and the normally closed contact K1-1 of the double-coil intermediate relay K1 is connected in series with it, thereby controlling its automatic start and stop. The control power indicator light H1 is independently connected in parallel in the circuit to indicate the working state of the control circuit being energized or de-energized.
[0059] As can be seen from the above, the safety protection circuit in this embodiment has a simple structure, can achieve protection against interruption of flow or stagnation of the operation of intermittent working devices such as daily fresh water pumps for transporting liquids, and at the same time has a self-locking function. The work is safe and reliable, can effectively reduce the failure rate, and also improves the operation reliability of related equipment.
[0060] This application also provides an intermittent working device, which includes: an operation control circuit and the above-mentioned safety protection circuit connected to the operation control circuit.
[0061] As Figure 1As shown, the safety protection circuit can be set in the operation control circuit of the intermittent liquid delivery equipment, and specifically includes: an automatic start-stop and flow anomaly cut-off control unit 1, a start-stop contactor and operation indication circuit unit 2, a flow switch and its delay control unit 3, a flow anomaly delay cut-off control unit 4, and a flow anomaly reset control unit 5.
[0062] The start-stop contactor and operation indication circuit unit 2 is connected to the automatic start-stop and flow anomaly cut-off control unit 1 through a thermal protection relay to form a start-stop operation branch.
[0063] The flow switch and its delay control unit 3 is connected in parallel with the start-stop operation branch.
[0064] The flow anomaly delay cut-off control unit 4 is connected in parallel with the start-stop operation branch.
[0065] The flow anomaly reset control unit 5 is connected in parallel with the start-stop operation branch.
[0066] As Figure 2 shown, the automatic start-stop and flow anomaly cut-off control unit 1 includes: a normally closed switch K1-1 of a double-coil intermediate relay K1, a normally closed high-pressure switch S3 of an operation control pressure relay, a normally open low-pressure switch S2 of the operation control pressure relay, and a normally open switch KM1-1 of an operation control contactor KM1.
[0067] The normally closed switch K1-1 of the double-coil intermediate relay K1, the normally closed high-pressure switch S3 of the operation control pressure relay, and the normally open low-pressure switch S2 of the operation control pressure relay are connected in series in sequence, and the normally open switch KM1-1 of the operation control contactor KM1 is connected in parallel with the normally open low-pressure switch S2 of the operation control pressure relay.
[0068] As Figure 3 shown, the start-stop contactor and operation indication circuit unit includes: an operation control contactor KM1 and an operation indicator light H2. The operation control contactor KM1 and the operation indicator light H2 are connected in parallel.
[0069] As Figure 4 shown, the flow switch and its delay control unit includes: a flow switch S4, a normally open switch KM1-2 of an operation control contactor KM1, and a time-delay relay KT1. The flow switch S4 is connected in series with the normally open switch KM1 of the operation control contactor KM1 and the time-delay relay KT1.
[0070] As Figure 5As shown, the flow anomaly delay cut-off control unit includes: the delay closing switch KT1 of the delay relay KT1 and the working coil of the double-coil intermediate relay K1. The delay closing switch KT1 of the delay relay KT1 is connected in series with the working coil of the double-coil intermediate relay K1.
[0071] As Figure 6 shown, the flow anomaly reset control unit includes: a reset button S5 and the reset coil of the double-coil intermediate relay K1. The reset button S5 and the reset coil of the double-coil intermediate relay K1 are connected in series.
[0072] In an embodiment, the intermittent working device includes a cabin alarm circuit, and the normally open switch of the double-coil intermediate relay is connected to the cabin alarm circuit.
[0073] In an embodiment, the intermittent working device includes a liquid delivery intermittent working device.
[0074] Please refer to Figure 7 , which shows the circuit structure diagram of the safety protection circuit described in the embodiment of the present application. As Figure 7 shown, in practical applications, the present application provides a safety protection circuit for a liquid delivery intermittent working device, which is used to be set in the operation control circuit of the liquid delivery intermittent working device. The operation control circuit of the liquid delivery intermittent working device includes an operation control contactor KM1, and the contact KM1 of the operation control contactor KM1 is connected to the power supply circuit of the intermittent working device: The safety protection circuit includes a double-coil intermediate contactor K1, a flow switch S4, and a delay relay KT1. The double-coil intermediate relay K1 is connected to the operation control circuit. The normally closed switch K1-1 of the double-coil intermediate contactor K1 is connected in series with the high-voltage normally closed switch S3 of the operation control pressure relay, the low-voltage normally open switch S2 of the operation control pressure relay, and the parallel circuit of the normally open switch KM1-1 of the operation control contactor KM1 to form an automatic start-stop and flow anomaly cut-off control unit. The operation control contactor KM1 and the operation indicator H2 are connected in parallel to form a start-stop contactor and operation indicator circuit unit. The flow switch S4 is connected in series with the normally open switch KM1-2 of the operation control contactor KM1 and the delay relay KT1 to form a flow switch and its delay control unit. The delay closing switch KT1 of the delay relay KT1 is connected in series with the working coil of the double-coil intermediate relay K1 to form a flow anomaly delay cut-off control unit. The reset button S5 is connected in series with the reset coil of the double-coil intermediate relay K1 to form a flow anomaly reset control unit. The normally open switch K1-2 of the double-coil intermediate relay is connected to the cabin alarm monitoring system.
[0075] Furthermore, the liquid intermittent working device is a daily fresh water pump M.
[0076] Thus, the present application avoids the continuous operation of the domestic fresh water pump in cases such as suction cavitation and abnormal stagnant flow. These abnormal operating conditions are avoided, which can cause the pump body to heat up, mechanical seals to leak, working efficiency to decrease, and in severe cases, the pump may overheat and be damaged or even cause a fire. When the domestic fresh water pump is used on a ship to supply domestic water and boiler feed water, the damage of the pump will not affect the safety of the crew's domestic water supply and the operation of the ship's boiler.
[0077] In several embodiments provided by the present application, it should be understood that the disclosed circuit can be implemented in other ways. For example, the circuit embodiments described above are merely illustrative. For example, the division of modules / units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces, and the indirect coupling or communication connection of devices or modules or units can be in electrical, mechanical or other forms.
[0078] The modules / units described as separate components may or may not be physically separated, and the components displayed as modules / units may or may not be physical modules, that is, they can be located in one place or distributed to multiple network units. Some or all of the modules / units can be selected according to actual needs to achieve the purpose of the embodiments of the present application. For example, in each embodiment of the present application, the functional modules / units can be integrated into a processing module, or each module / unit can exist physically alone, or two or more modules / units can be integrated into one module / unit.
[0079] The above embodiments are only illustrative of the principles and effects of the present application and are not used to limit the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present application should still be covered by the claims of the present application.
Claims
1. A safety protection circuit, characterized in that: The safety protection circuit comprises: Automatic start and stop and flow abnormality cut-off control unit; The start-stop contactor and the operation indication circuit unit are connected to the automatic start-stop and flow abnormality cut-off control unit through a thermal protection relay to form a start-stop operation branch; A flow switch and a time delay control unit thereof are connected in parallel with the start-stop operation branch; A flow abnormality delay cut-off control unit connected in parallel with the start-stop operation branch; A flow anomaly reset control unit is connected in parallel with the start-stop operation branch.
2. The safety protection circuit according to claim 1, characterized in that: The automatic start-stop and flow abnormality cut-off control unit includes: a normally closed switch of a double-coil intermediate relay, a high-voltage normally closed switch of an operation control pressure relay, a low-voltage normally open switch of an operation control pressure relay, and a normally open switch of an operation control contactor; The normally closed switch of the double-coil intermediate relay, the high-voltage normally closed switch of the operation control pressure relay, and the low-voltage normally open switch of the operation control pressure relay are connected in series in sequence, and the normally open switch of the operation control contactor is connected in parallel with the low-voltage normally open switch of the operation control pressure relay.
3. The safety protection circuit according to claim 2, characterized in that: The start-stop contactor and operation indication circuit unit comprises: an operation control contactor and an operation indicator light; The operation control contactor and the operation indicator light are connected in parallel.
4. The safety protection circuit according to claim 3, characterized in that: The flow switch and its time delay control unit include: a flow switch, a normally open switch of an operation control contactor and a time delay relay; The flow switch is connected in series with the normally open switch of the operation control contactor and the time delay relay.
5. The safety protection circuit according to claim 4, characterized in that: The abnormal flow delay cut-off control unit comprises: a delayed closing switch of the delay relay and a working coil of the double-coil intermediate relay; The delayed closing switch of the time delay relay is connected in series with the working coil of the double-coil intermediate relay.
6. The safety protection circuit according to claim 5, characterized in that: The flow abnormality reset control unit comprises: a reset button and a reset coil of the double-coil intermediate relay; The reset button and the reset coil of the double-coil intermediate relay are connected in series.
7. The safety protection circuit according to claim 2, characterized in that: The normally open switch of the double-coil intermediate relay is connected to the cabin alarm circuit.
8. An intermittent working device, characterized in that: The intermittent working equipment comprises: an operation control circuit and a safety protection circuit according to any one of claims 1 to 7 connected to the operation control circuit.
9. The intermittent working device according to claim 8, characterized in that: The intermittent working equipment comprises a cabin alarm circuit, and the normally open switch of the double-coil intermediate relay is connected to the cabin alarm circuit.
10. The intermittent working device according to claim 8, characterized in that: The intermittent working equipment includes liquid conveying intermittent working equipment.