Control loop of fire-fighting stabilized pressure pump

Abstract

The utility model relates to the technical field of fire fighting, in particular to a control loop of a fire-fighting stabilized pressure pump, which comprises a power line, a zero line and a start-stop loop, the start-stop loop comprises a first selection change-over switch, a second selection change-over switch, a third selection change-over switch and a fourth selection change-over switch, the second contact, the fourth contact and the sixth contact respectively correspond to the first contact, the third contact and the fifth contact; the normally open switch and the normally closed switch are connected, and the normally open switch is connected to the second contact; the first relay comprises a first coil connected to the normally-closed switch and the zero line; the remote start-stop control switch comprises a first contact connected to the sixth contact and a second contact connected to the first coil; the pressure control switch comprises a fifth contact, a third contact connected to the fourth contact and a fourth contact arranged on the first coil; and the second relay comprises a first normally-closed contact and a second coil connected to the fifth contact and the null line, and the fourth contact is connected to the first coil through the first normally-closed contact.

Description

Technical Field

[0001] This utility model relates to the field of fire protection technology, specifically to a control circuit for a fire-fighting pressure-stabilizing pump. Background Technology

[0002] Fire-fighting pressure-stabilizing pumps play a crucial role in fire protection systems, ensuring stable pressure in the fire water supply system. During non-fire periods, they must guarantee sufficient system pressure to provide immediate water for firefighting in the event of a fire. A common configuration for fire-fighting pressure-stabilizing pumps is two pumps, A and B, operating in a one-in-operation-one-standby mode, with start-stop control based on system pressure changes. For example, when the system pressure drops below a certain limit due to factors such as pipe leaks or insufficient water usage, the pressure-stabilizing pump automatically starts to replenish the pressure; when the pressure rises back to the limit, the pressure-stabilizing pump stops operating.

[0003] Currently, the control methods for fire-fighting pressure-stabilizing pumps are relatively simple, mainly relying on pressure thresholds to control the pump's start and stop, lacking the ability to flexibly respond to complex operating conditions. This single control method results in a low system fault tolerance rate. Once the pressure sensor malfunctions or the control circuit malfunctions, it may cause the pressure-stabilizing pump to malfunction, such as frequent start-stop or failure to start normally, seriously affecting the reliability of the fire protection system.

[0004] Therefore, how to overcome the shortcomings of the existing technology mentioned above has become the subject of this utility model. Utility Model Content

[0005] The purpose of this invention is to provide a control circuit for a fire-fighting pressure-stabilizing pump.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A control circuit for a fire-fighting pressure-stabilizing pump includes a power supply line and a neutral line, and also includes a start-stop circuit, wherein the start-stop circuit includes:

[0008] The first selection switch includes a first contact, a third contact, and a fifth contact, all connected to the power line, and also includes a second contact corresponding to the first contact, a fourth contact corresponding to the third contact, and a sixth contact corresponding to the fifth contact.

[0009] A normally open switch is connected to the second contact;

[0010] A normally closed switch is connected to the normally open switch;

[0011] The first relay includes a first coil with its two ends respectively connected to the normally closed switch and the neutral wire;

[0012] The remote start / stop control switch includes a first contact connected to the sixth contact and a second contact connected to the first coil;

[0013] A pressure control switch includes a fifth contact, a third contact connected to the fourth contact, and a fourth contact connected to the first coil;

[0014] The second relay includes a second coil with its two ends connected to the fifth contact and the neutral wire respectively, and a first normally closed contact. The fourth contact is connected to the first coil through the first normally closed contact.

[0015] When the system pressure is lower than the predetermined value, the third contact is connected to the fourth contact; when the system pressure is equal to or higher than the predetermined value, the third contact is connected to the fifth contact.

[0016] This application uses fire-fighting pressure-stabilizing pumps, including pump A and pump B, as examples for illustration.

[0017] The first relay is the core structure, controlling the power supply to pumps A and B, as shown in the attached diagram.

[0018] Taking a normally open switch as an example, this switch has a normally open structure, meaning it is initially in the open state. Other similar structures in this application (such as each normally open contact) refer to this description. In some cases, normally open switches and normally closed switches can be combined into a single control switch, meaning only one of them is retained. Using both is more conducive to manual control.

[0019] In the above scheme, the control loop has three control methods:

[0020] In the first control method, the first contact and the second contact are connected. The first coil is energized by closing the normally open switch and de-energized by opening the normally closed switch. This process is a local manual control process.

[0021] In the second control method, the fifth contact and the sixth contact are connected, and the remote operation controls the first contact and the second contact to connect, so that the first coil is energized. After the first contact and the second contact are disconnected, the first coil is de-energized. This process is the remote start-stop control process.

[0022] In the third control method, the third contact and the fourth contact are connected. When the system pressure is lower than the predetermined value, the third contact and the fourth contact are connected, and the first coil is energized. When the system pressure is equal to or higher than the predetermined value, the third contact and the fifth contact are connected, and the second coil is energized. The first normally closed contact turns to the open state so that the first coil is de-energized. This is the system pressure control process.

[0023] The control loop in this application has three control modes, which can realize local control or remote control, manual control or automatic control, to meet a variety of needs and expand the scope of application of this application. The three control modes can be used together to improve the fault tolerance rate of the control loop in the event of a fault.

[0024] In some implementations, the power line is equipped with a fuse coil to protect against circuit overload.

[0025] In some implementations, a power indicator light is also included, which is connected to the power cord and the neutral wire.

[0026] It should be noted that, taking a normally open switch as an example, and similar settings in the attached diagram, refer to this explanation: After the normally open switch closes, energizing the first coil of the first relay, the normally open switch automatically returns to the open state. To ensure that the first coil continues to be energized, a normally open contact of the first relay is connected in parallel with the normally open switch. When the first coil is energized, the normally open contact closes. At this time, even if the normally open switch automatically returns to the open state, the first coil can still be energized through this normally open contact. Subsequently, when the normally closed switch is opened to de-energize the first coil, the normally closed switch can also automatically reset.

[0027] A further technical solution includes a pump selection circuit connected in parallel with the start-stop circuit, the pump selection circuit comprising:

[0028] The second selection switch includes a seventh contact and a ninth contact, both connected to the power line, and also includes an eighth contact corresponding to the seventh contact and a tenth contact corresponding to the ninth contact.

[0029] The third relay includes a third coil with its two ends respectively connected to the eighth contact and the neutral wire;

[0030] The fourth relay includes a fourth coil with its two ends connected to the tenth contact and the neutral wire, respectively.

[0031] In the above, whether pump A and pump B start depends solely on whether the first coil is energized. The control factor is singular, making it impossible to flexibly and selectively control pump A and pump B.

[0032] This embodiment introduces a third relay and a fourth relay. Here, we will explain the correspondence between the third coil and pump A, and the fourth coil and pump B: When the seventh contact and the eighth contact are connected, the third coil is energized and pump A is started; when the ninth contact and the tenth contact are connected, the fourth coil is energized and pump B is started.

[0033] This embodiment adds the necessary conditions for starting pump A and pump B, allowing selective starting of either pump A or pump B, further expanding the applicability of this application.

[0034] In a further technical solution, the second selection switch also includes an eleventh contact connected to the power line and a twelfth contact corresponding to the eleventh contact;

[0035] The pump selection circuit also includes:

[0036] The first contactor includes a first normally open contact connected to the twelfth contact;

[0037] The second contactor includes a second normally closed contact connected to the first normally open contact;

[0038] The fifth relay includes a fifth coil with its two ends connected to the second normally closed contact and the neutral wire, and a second normally open contact and a third normally closed contact, both connected to the twelfth contact. The second normally open contact is connected to the fourth coil, and the third normally closed contact is connected to the third coil.

[0039] In the above embodiments, when the third coil is energized, it can be regarded as the mode of using pump A as the main power source, and when the fourth coil is energized, it can be regarded as the mode of using pump B as the main power source.

[0040] This implementation adds a mode in which pump A and pump B are used alternately. This mode is based on the connection of the eleventh and twelfth contacts, and the operation process is as follows: Since the second normally open contact is open and the third normally closed contact is closed, the third coil is initially energized, and pump A runs; the operation of pump A energizes the first contactor, causing the first normally open contact to close, and then the fifth coil is energized, causing the second normally open contact to close and the third normally closed contact to open, resulting in the third coil being de-energized, and the current flows through the second normally open contact to the fourth relay; after the fourth coil is energized, pump B runs, energizing the second contactor, causing the second normally closed contact to open, and then the fifth coil is de-energized, causing the second normally open contact and the third normally closed contact to return to their initial state.

[0041] This embodiment adds a mode of alternating use of pump A and pump B, further expanding the applicability of this application.

[0042] In the mode of alternating use of pump A and pump B, pump A and pump B operate alternately, with a balanced number of uses, thus extending the service life of the equipment.

[0043] The above examples illustrate some of the parallel configurations shown in the diagram. Here, we will illustrate them again: The fifth relay has a parallel normally open contact connected in parallel with the first normally open contact. After the first normally open contact closes, it automatically opens again. The closed parallel normally open contact ensures that the fifth coil continues to be energized.

[0044] In some embodiments, the first contactor has a normally closed contact, and the second normally open contact and the third normally closed contact are both connected to the twelfth contact through this normally closed contact, which has an automatic reset setting.

[0045] In a further technical solution, the first relay also includes a third normally open contact connected to the power line;

[0046] The third relay further includes a fourth normally open contact connected to the third normally open contact;

[0047] The first contactor also includes a sixth coil with its two ends connected to the fourth normally open contact and the neutral wire, respectively;

[0048] The fourth relay further includes a fifth normally open contact connected to the third normally open contact;

[0049] The second contactor also includes a seventh coil, with its two ends connected to the fifth normally open contact and the neutral wire, respectively.

[0050] This application describes pump A with the sixth coil and pump B with the seventh coil.

[0051] After the first coil of the first relay is energized, the third normally open contact closes. Using the third relay as an example, the fourth relay follows the same explanation: When the third coil of the third relay is energized, the fourth normally open contact closes, energizing the sixth coil of the first contactor and causing pump A to run.

[0052] This embodiment further clarifies the coordination relationship between the first relay, the third relay, and the fourth relay, allowing selective activation of either pump A or pump B, thus further expanding the applicability of this application.

[0053] Taking the sixth coil as an example, the seventh coil is described in the same way: In some embodiments, an operation indicator light is provided in parallel with the sixth coil.

[0054] In a further technical solution, the second contactor also includes a fourth normally closed contact, which is connected to the sixth coil via the fourth normally closed contact;

[0055] The first contactor also includes a fifth normally closed contact, which is connected to the seventh coil via the fifth normally closed contact.

[0056] Taking the fourth normally closed contact as an example, the fifth normally closed contact is explained in the same way: after the seventh coil of the second contactor is energized, the fifth normally closed contact opens. At this time, it can ensure that the sixth coil of the first contactor cannot be energized, thus preventing pump A from being put into use at an inappropriate stage due to unexpected circumstances, and playing a protective role.

[0057] Further technical solutions also include a first thermal relay with a sixth normally closed contact and a second thermal relay with a seventh normally closed contact.

[0058] The fourth normally closed contact is connected to the sixth coil through the sixth normally closed contact;

[0059] The fifth normally closed contact is connected to the seventh coil through the seventh normally closed contact.

[0060] Taking the sixth normally closed contact as an example, the seventh normally closed contact is explained in the same way: the first thermal relay plays an overload protection role. When the sixth normally closed contact is opened, the sixth coil turns to a de-energized state to protect the circuit for long-term operation.

[0061] In some embodiments, taking a first thermal relay as an example, the second thermal relay is described accordingly: the first thermal relay has a normally open contact and a fault indicator light. The normally open contact is connected to the power line and the neutral line. The fault indicator light is connected in series with the normally open contact. When the sixth normally closed contact is opened, the normally open contact is closed, thereby activating the fault indicator light.

[0062] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0063] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0064] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0065] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the case.

[0066] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0067] The working principle and advantages of this utility model are as follows:

[0068] In this application, the control loop has three control methods:

[0069] In the first control method, the first contact and the second contact are connected. The first coil is energized by closing the normally open switch and de-energized by opening the normally closed switch. This process is a local manual control process.

[0070] In the second control method, the fifth contact and the sixth contact are connected, and the remote operation controls the first contact and the second contact to connect, so that the first coil is energized. After the first contact and the second contact are disconnected, the first coil is de-energized. This process is the remote start-stop control process.

[0071] In the third control method, the third contact and the fourth contact are connected. When the system pressure is lower than the predetermined value, the third contact and the fourth contact are connected, and the first coil is energized. When the system pressure is equal to or higher than the predetermined value, the third contact and the fifth contact are connected, and the second coil is energized. The first normally closed contact turns to the open state so that the first coil is de-energized. This is the system pressure control process.

[0072] The control loop in this application has three control modes, which can realize local control or remote control, manual control or automatic control, to meet a variety of needs and expand the scope of application of this application. The three control modes can be used together to improve the fault tolerance rate of the control loop in the event of a fault. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of the control circuit of the fire-fighting pressure-stabilizing pump according to an embodiment of the present invention;

[0074] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0075] Figure 3 for Figure 1 Enlarged view at point B in the middle;

[0076] Figure 4 for Figure 1 Enlarged view of point C in the middle.

[0077] In the attached diagram: 1. Power cord; 2. Neutral wire; 3. Start / stop circuit; 311. First contact; 312. Second contact; 313. Third contact; 314. Fourth contact; 315. Fifth contact; 316. Sixth contact; 32. Normally open switch; 33. Normally closed switch; 341. First coil; 342. Third normally open contact; 351. First contact; 352. Second contact; 361. Fifth contact; 362. Third contact; 363. Fourth contact; 371. Second coil; 372. First normally closed contact; 4. Power indicator light; 5. Pump selection circuit; 511. Seventh contact. 512. Eighth contact; 513. Ninth contact; 514. Tenth contact; 515. Eleventh contact; 516. Twelfth contact; 521. Third coil; 522. Fourth normally open contact; 531. Fourth coil; 532. Fifth normally open contact; 541. First normally open contact; 542. Sixth coil; 543. Fifth normally closed contact; 551. Second normally closed contact; 552. Seventh coil; 553. Fourth normally closed contact; 561. Fifth coil; 562. Second normally open contact; 563. Third normally closed contact; 571. Sixth normally closed contact; 581. Seventh normally closed contact. Detailed Implementation

[0078] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0079] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0080] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0081] See Figures 1-4 A control circuit for a fire-fighting pressure-stabilizing pump includes a power supply line 1 and a neutral line 2, and also includes a start-stop circuit 3, wherein the start-stop circuit 3 includes:

[0082] The first selection switch includes a first contact 311, a third contact 313 and a fifth contact 315, all connected to the power line 1, and also includes a second contact 312 corresponding to the first contact 311, a fourth contact 314 corresponding to the third contact 313 and a sixth contact 316 corresponding to the fifth contact 315.

[0083] Normally open switch 32 is connected to the second contact 312;

[0084] Normally closed switch 33 is connected to normally open switch 32;

[0085] The first relay includes a first coil 341 with its two ends connected to the normally closed switch 33 and the neutral wire 2, respectively.

[0086] The remote start / stop control switch includes a first contact 351 connected to the sixth contact 316 and a second contact 352 connected to the first coil 341;

[0087] The pressure control switch includes a fifth contact 361, a third contact 362 connected to the fourth contact 314, and a fourth contact 363 connected to the first coil 341.

[0088] The second relay includes a second coil 371 with its two ends connected to the fifth contact 361 and the neutral wire 2 respectively, and also includes a first normally closed contact 372. The fourth contact 363 is connected to the first coil 341 through the first normally closed contact 372.

[0089] When the system pressure is lower than the predetermined value, the third contact 362 is connected to the fourth contact 363; when the system pressure is equal to or higher than the predetermined value, the third contact 362 is connected to the fifth contact 361.

[0090] This application uses fire-fighting pressure-stabilizing pumps, including pump A and pump B, as examples for illustration.

[0091] The first relay is the core structure, controlling the power supply to pumps A and B, as shown in the attached diagram.

[0092] Taking normally open switch 32 as an example, this switch has a normally open structure, meaning it is initially in the open state. Other similar structures in this application (such as each normally open contact) refer to this description. In some cases, normally open switch 32 and normally closed switch 33 can be combined into a single control switch, that is, only one of them is retained. Using both is more conducive to manual control.

[0093] In this application, the control loop has three control methods:

[0094] In the first control method, the first contact 311 and the second contact 312 are connected. The first coil 341 is energized by closing the normally open switch 32, and the first coil 341 is de-energized by opening the normally closed switch 33. This process is a local manual control process.

[0095] In the second control method, the fifth contact 315 and the sixth contact 316 are connected, and the remote operation control first contact 351 and second contact 352 are connected, so that the first coil 341 is energized. After the first contact 351 and the second contact 352 are disconnected, the first coil 341 is de-energized. This process is the remote start-stop control process.

[0096] In the third control method, the third contact 313 and the fourth contact 314 are connected. When the system pressure is lower than the predetermined value, the third contact 362 and the fourth contact 363 are connected, and the first coil 341 is energized. When the system pressure is equal to or higher than the predetermined value, the third contact 362 and the fifth contact 361 are connected, and the second coil 371 is energized. The first normally closed contact 372 turns to the open state so that the first coil 341 is de-energized. This is the system pressure control process.

[0097] The control loop in this application has three control modes, which can realize local control or remote control, manual control or automatic control, to meet a variety of needs and expand the scope of application of this application. The three control modes can be used together to improve the fault tolerance rate of the control loop in the event of a fault.

[0098] In some embodiments, the power line 1 is provided with a fuse coil to protect against circuit overload.

[0099] In some embodiments, a power indicator light 4 is also included, which is connected to the power cord 1 and the neutral wire 2.

[0100] It should be noted that, taking the normally open switch 32 as an example, similar settings in the attached diagram are described in the following way: After the normally open switch 32 closes and energizes the first coil 341 of the first relay, the normally open switch 32 automatically returns to the open state. To ensure that the first coil 341 continues to be energized, a normally open contact of the first relay is connected in parallel with the normally open switch 32. When the first coil 341 is energized, the normally open contact closes. At this time, even if the normally open switch 32 automatically returns to the open state, the first coil 341 can still be energized through this normally open contact. Subsequently, the normally closed switch 33 is opened to de-energize the first coil 341, and the normally closed switch 33 can also automatically reset.

[0101] See Figure 3 In this embodiment, a pump selection circuit 5 connected in parallel with the start-stop circuit 3 is also included. The pump selection circuit 5 includes:

[0102] The second selection switch includes a seventh contact 511 and a ninth contact 513, both connected to the power line 1, and also includes an eighth contact 512 corresponding to the seventh contact 511 and a tenth contact 514 corresponding to the ninth contact 513.

[0103] The third relay includes a third coil 521 with its two ends connected to the eighth contact 512 and the neutral wire 2, respectively;

[0104] The fourth relay includes a fourth coil 531 with its two ends connected to the tenth contact 514 and the neutral wire 2, respectively.

[0105] In the above, whether pump A and pump B start depends solely on whether the first coil 341 is energized. The control factor is singular, making it impossible to flexibly and selectively control pump A and pump B.

[0106] This embodiment introduces a third relay and a fourth relay. Here, we will explain the connection between the third coil 521 and pump A, and the fourth coil 531 and pump B: When the seventh contact 511 and the eighth contact 512 are connected, the third coil 521 is energized and pump A is started; when the ninth contact 513 and the tenth contact 514 are connected, the fourth coil 531 is energized and pump B is started.

[0107] This embodiment adds the necessary conditions for starting pump A and pump B, allowing selective starting of either pump A or pump B, further expanding the applicability of this application.

[0108] See Figure 3 In this embodiment, the second selection switch further includes an eleventh contact 515 connected to the power line 1 and a twelfth contact 516 corresponding to the eleventh contact 515;

[0109] The pump selection circuit 5 also includes:

[0110] The first contactor includes a first normally open contact 541 connected to the twelfth contact 516;

[0111] The second contactor includes a second normally closed contact 551 connected to the first normally open contact 541;

[0112] The fifth relay includes a fifth coil 561 with its two ends connected to the second normally closed contact 551 and the neutral wire 2 respectively, and a second normally open contact 562 and a third normally closed contact 563 both connected to the twelfth contact 516. The second normally open contact 562 is connected to the fourth coil 531, and the third normally closed contact 563 is connected to the third coil 521.

[0113] In the above embodiments, when the third coil 521 is energized, it can be regarded as the mode of A pump being the main power source, and when the fourth coil 531 is energized, it can be regarded as the mode of B pump being the main power source.

[0114] This embodiment adds a mode in which pump A and pump B are used alternately. This mode is based on the connection of the eleventh contact 515 and the twelfth contact 516. The operation process is as follows: Since the second normally open contact 562 is open and the third normally closed contact 563 is closed, the third coil 521 is initially energized, and pump A runs. The operation of pump A energizes the first contactor, causing the first normally open contact 541 to close. Then, the fifth coil 561 is energized, causing the second normally open contact 562 to close and the third normally closed contact 563 to open, resulting in the third coil 521 being de-energized. The current flows through the second normally open contact 562 to the fourth relay. After the fourth coil 531 is energized, pump B runs, energizing the second contactor and causing the second normally closed contact 551 to open. Then, the fifth coil 561 is de-energized, causing the second normally open contact 562 and the third normally closed contact 563 to return to their initial state.

[0115] This embodiment adds a mode of alternating use of pump A and pump B, further expanding the applicability of this application.

[0116] In the mode of alternating use of pump A and pump B, pump A and pump B operate alternately, with a balanced number of uses, thus extending the service life of the equipment.

[0117] The above examples illustrate some of the parallel configurations shown in the figure. Here, we will illustrate them again: The fifth relay has a parallel normally open contact connected in parallel with the first normally open contact 541. After the first normally open contact 541 is closed, it automatically opens again. The closed parallel normally open contact ensures that the fifth coil 561 continues to be energized.

[0118] In some embodiments, the first contactor has a normally closed contact, through which the second normally open contact 562 and the third normally closed contact 563 are both connected to the twelfth contact 516, and the normally closed contact has an automatic reset setting.

[0119] See Figure 4 In this embodiment, the first relay further includes a third normally open contact 342 connected to the power line 1;

[0120] The third relay also includes a fourth normally open contact 522 connected to the third normally open contact 342;

[0121] The first contactor also includes a sixth coil 542 with its two ends respectively connected to the fourth normally open contact 522 and the neutral wire 2;

[0122] The fourth relay also includes a fifth normally open contact 532 connected to the third normally open contact 342;

[0123] The second contactor also includes a seventh coil 552 with its two ends connected to the fifth normally open contact 532 and the neutral wire 2, respectively.

[0124] This application describes pump A with the sixth coil 542 and pump B with the seventh coil 552.

[0125] After the first coil 341 of the first relay is energized, the third normally open contact 342 closes. Taking the third relay as an example, the fourth relay is described in the same way: when the third coil 521 of the third relay is energized, the fourth normally open contact 522 closes, which energizes the sixth coil 542 of the first contactor, causing pump A to run.

[0126] This embodiment further clarifies the coordination relationship between the first relay, the third relay, and the fourth relay, allowing selective activation of either pump A or pump B, thus further expanding the scope of application of this application.

[0127] Taking the sixth coil 542 as an example, the seventh coil 552 is described in the same way: In some embodiments, an operation indicator light is provided in parallel with the sixth coil 542.

[0128] See Figure 4 In this embodiment, the second contactor further includes a fourth normally closed contact 553, and the fourth normally open contact 522 is connected to the sixth coil 542 through the fourth normally closed contact 553;

[0129] The first contactor also includes a fifth normally closed contact 543, and the fifth normally open contact 532 is connected to the seventh coil 552 through the fifth normally closed contact 543.

[0130] Taking the fourth normally closed contact 553 as an example, the fifth normally closed contact 543 is explained in the same way: after the seventh coil 552 of the second contactor is energized, the fifth normally closed contact 543 opens. At this time, it can be ensured that the sixth coil 542 of the first contactor cannot be energized, so as to prevent pump A from being put into use at an inappropriate stage due to unexpected circumstances, thus playing a protective role.

[0131] See Figure 4 In this embodiment, it also includes a first thermal relay with a sixth normally closed contact 571 and a second thermal relay with a seventh normally closed contact 581.

[0132] The fourth normally closed contact 553 is connected to the sixth coil 542 through the sixth normally closed contact 571;

[0133] The fifth normally closed contact 543 is connected to the seventh coil 552 through the seventh normally closed contact 581.

[0134] Taking the sixth normally closed contact 571 as an example, the seventh normally closed contact 581 is explained in the same way: the first thermal relay plays an overload protection role. When the sixth normally closed contact 571 is opened, the sixth coil 542 turns to a de-energized state to protect the circuit for long-term operation.

[0135] In some embodiments, taking a first thermal relay as an example, the second thermal relay is described herein: the first thermal relay has a normally open contact and a fault indicator light. The normally open contact is connected to the power line 1 and the neutral line 2. The fault indicator light is connected in series with the normally open contact. When the sixth normally closed contact 571 is opened, the normally open contact is closed, thereby activating the fault indicator light.

[0136] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A control circuit for a fire-fighting pressure-stabilizing pump, comprising a power supply line (1) and a neutral line (2), characterized in that: The control loop also includes a start-stop loop (3), which includes: The first selection switch includes a first contact (311), a third contact (313) and a fifth contact (315) all connected to the power line (1), and also includes a second contact (312) corresponding to the first contact (311), a fourth contact (314) corresponding to the third contact (313) and a sixth contact (316) corresponding to the fifth contact (315). A normally open switch (32) is connected to the second contact (312); Normally closed switch (33) is connected to normally open switch (32); The first relay includes a first coil (341) with its two ends connected to the normally closed switch (33) and the neutral wire (2) respectively. The remote start / stop control switch includes a first contact (351) connected to the sixth contact (316) and a second contact (352) connected to the first coil (341). The pressure control switch includes a fifth contact (361), a third contact (362) connected to the fourth contact (314), and a fourth contact (363) connected to the first coil (341). The second relay includes a second coil (371) with its two ends connected to the fifth contact (361) and the neutral wire (2) respectively, and also includes a first normally closed contact (372). The fourth contact (363) is connected to the first coil (341) through the first normally closed contact (372). When the system pressure is lower than the predetermined value, the third contact (362) is connected to the fourth contact (363); when the system pressure is equal to or higher than the predetermined value, the third contact (362) is connected to the fifth contact (361).

2. The control circuit of a fire-fighting pressure-stabilizing pump according to claim 1, characterized in that: It also includes a pump selection circuit (5) connected in parallel with the start-stop circuit (3), the pump selection circuit (5) comprising: The second selection switch includes a seventh contact (511) and a ninth contact (513) both connected to the power line (1), and also includes an eighth contact (512) corresponding to the seventh contact (511) and a tenth contact (514) corresponding to the ninth contact (513). The third relay includes a third coil (521) with its two ends connected to the eighth contact (512) and the neutral wire (2) respectively. The fourth relay includes a fourth coil (531) with its two ends connected to the tenth contact (514) and the neutral line (2), respectively.

3. The control circuit of a fire-fighting pressure-stabilizing pump according to claim 2, characterized in that: The second selection switch further includes an eleventh contact (515) connected to the power line (1) and a twelfth contact (516) corresponding to the eleventh contact (515). The pump selection circuit (5) also includes: The first contactor includes a first normally open contact (541) connected to the twelfth contact (516). The second contactor includes a second normally closed contact (551) connected to the first normally open contact (541). The fifth relay includes a fifth coil (561) with its two ends connected to the second normally closed contact (551) and the neutral wire (2) respectively, and a second normally open contact (562) and a third normally closed contact (563) both connected to the twelfth contact (516). The second normally open contact (562) is connected to the fourth coil (531), and the third normally closed contact (563) is connected to the third coil (521).

4. The control circuit of a fire-fighting pressure-stabilizing pump according to claim 3, characterized in that: The first relay also includes a third normally open contact (342) connected to the power line (1). The third relay also includes a fourth normally open contact (522) connected to the third normally open contact (342); The first contactor also includes a sixth coil (542) with its two ends connected to the fourth normally open contact (522) and the neutral wire (2), respectively. The fourth relay also includes a fifth normally open contact (532) connected to the third normally open contact (342). The second contactor also includes a seventh coil (552) with its two ends connected to the fifth normally open contact (532) and the neutral line (2), respectively.

5. The control circuit of a fire-fighting pressure-stabilizing pump according to claim 4, characterized in that: The second contactor also includes a fourth normally closed contact (553), and the fourth normally open contact (522) is connected to the sixth coil (542) through the fourth normally closed contact (553); The first contactor also includes a fifth normally closed contact (543), and the fifth normally open contact (532) is connected to the seventh coil (552) through the fifth normally closed contact (543).

6. The control circuit of a fire-fighting pressure-stabilizing pump according to claim 5, characterized in that: It also includes a first thermal relay with a sixth normally closed contact (571) and a second thermal relay with a seventh normally closed contact (581); The fourth normally closed contact (553) is connected to the sixth coil (542) through the sixth normally closed contact (571); The fifth normally closed contact (543) is connected to the seventh coil (552) through the seventh normally closed contact (581).

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