CAFS output pressure protection control method and device

Abstract

The invention provides a CAFS output pressure protection control method, and belongs to the field of fire control, and the method comprises the steps: S1, setting a pressure protection limit value; s2, when the output pressure is larger than the low starting value and smaller than the high starting value, entering S7; when the output pressure is greater than the high starting value, entering S3, and when the output pressure is smaller than the low starting value, entering S5; s3, the water flow is kept unchanged, whether the output pressure is larger than a high alarm value or not is judged, if yes, the air flow is reduced till the gas-liquid ratio reaches the lower limit value, and S4 is executed; s4, judging whether the output pressure is greater than a high protection value, if so, reducing the water flow until the output pressure is less than a high alarm value; s5, the water flow is kept unchanged, whether the output pressure is smaller than a low alarm value or not is judged, if yes, the air flow is increased till the gas-liquid ratio reaches the upper limit value, and S6 is executed; s6, whether the output pressure is smaller than a low protection value or not is judged, and if yes, the water flow is increased till the output pressure is larger than a low alarm value; s7, adjusting the water flow; the invention further provides a device. And automatic protection of output pressure is realized.

Description

Technical Field

[0001] This invention relates to the field of fire protection control technology, and in particular to a method and device for protecting and controlling the output pressure of CAFS (Cautioned Fire Protection System). Background Technology

[0002] Compressed air foam systems (CAFS) have advantages such as good fire extinguishing and cooling efficiency, high fire extinguishing efficiency, and water saving. They are suitable for fighting hot oil fires in large transformers in UHV converter stations and are an advanced fire extinguishing technology that can significantly improve the fire protection capabilities of existing UHV converter stations.

[0003] Currently, ultra-high voltage converter stations have begun to install CAFS (Continuous Fire Protection System) as a fire extinguishing method for converter transformers. Taking a newly built ±800kV ultra-high voltage converter station as an example, the entire station is equipped with two CAFS systems with a flow rate of 4000L / min. The terminal release devices include sprinkler pipes, fixed fire monitors, mobile aerial ladder robots, and fire hydrants. When the system is in use, if there are changes in the type or number of terminal release devices, relying solely on the flow rate and head characteristics of the fire pump for passive adjustment may result in situations where the output pressure is too high, causing the air compressor to depressurize, or the output pressure is too low, causing the range to not meet requirements. Summary of the Invention

[0004] The technical problem to be solved by this invention is: how to solve the problem that the system output pressure is too high or too low due to changes in the type or number of end release devices during the operation of a compressed air foam fire extinguishing system.

[0005] This invention solves the above-mentioned technical problems through the following technical solution: a protection and control method for CAFS output pressure, the method comprising:

[0006] S1. Set pressure protection limits, including high start value, high alarm value, high protection value, low start value, low alarm value and low protection value; collect output pressure, water flow rate, foam liquid flow rate and air flow rate; calculate gas-liquid ratio and foam liquid mixing ratio.

[0007] S2. When the output pressure is greater than the low start value and less than the high start value, proceed to step S7; when the output pressure is greater than the high start value, proceed to step S3; when the output pressure is less than the low start value, proceed to step S5.

[0008] S3. Keep the water flow rate constant and determine whether the output pressure is greater than the high alarm value. If so, reduce the air flow rate until the gas-liquid ratio reaches the lower limit value and proceed to S4. If not, proceed to S7.

[0009] S4. Determine if the output pressure is greater than the high protection value. If so, reduce the water flow until the output pressure is less than the high alarm value, and simultaneously adjust the foam liquid flow until the foam liquid mixing ratio reaches the mixing ratio set value. If not, proceed to step S7.

[0010] S5. Keep the water flow rate constant and determine whether the output pressure is lower than the low alarm value. If yes, increase the air flow rate until the gas-liquid ratio reaches the upper limit value and proceed to step S6. If no, proceed to step S7.

[0011] S6. Determine if the output pressure is less than the low protection value. If yes, increase the water flow until the output pressure is greater than the low alarm value, and simultaneously adjust the foam liquid flow until the foam liquid mixing ratio reaches the mixing ratio set value. If no, proceed to step S7.

[0012] S7. Adjust the water flow rate until the water flow rate meets the preset conditions, which are between the lower and higher limits.

[0013] Beneficial Effects: This invention achieves multi-level pressure control by setting high start-up values, high alarm values, high protection values, low start-up values, low alarm values, and low protection values. It can preemptively process pressure before it reaches the equipment's protection shutdown threshold. When the output pressure is greater than the high start-up value or less than the low start-up value, the water flow rate remains constant. This first-stage action locks in reverse flow regulation to prevent the pressure from continuing to increase or decrease, thus exceeding the equipment's normal operating range. When the output pressure is greater than the high alarm value or less than the low alarm value, the air flow rate is adjusted, thereby regulating the gas-liquid ratio. The second-stage action adjusts the gas-liquid ratio to maintain the flow rate and prevent a decrease in fire extinguishing capacity. When the output pressure is greater than the high protection value or less than the low protection value, the water flow rate is adjusted and the foam liquid flow rate is adjusted simultaneously. The third-stage action adjusts the flow rate to the second-stage alarm value while implementing the first two stages. This maximizes the output flow rate and fire extinguishing capacity while maintaining system operation, thereby achieving automatic protection of the compressed air foam fire extinguishing system output pressure. When the system output pressure is too high or too low, it can actively adjust, improving the stability and safety of system operation.

[0014] Preferably, the gas-liquid ratio R is calculated as follows:

[0015]

[0016] Where F1 is the water flow rate, F2 is the foam liquid flow rate, and F3 is the air flow rate.

[0017] Preferably, the foam liquid mixing ratio H is calculated as follows:

[0018]

[0019] Where F1 is the water flow rate and F2 is the foam liquid flow rate.

[0020] Preferably, the order of the pressure protection limits is: high protection value > high alarm value > high start value > low start value > low alarm value > low protection value.

[0021] Preferably, the process of adjusting the water flow rate is as follows: determine whether the average water flow rate within the statistical window T meets the preset conditions. If the conditions are met, lock the water flow rate adjustment function. If the conditions are not met, calculate the flow rate deviation Δ and adjust the water flow rate.

[0022] Preferably, the average water flow rate WF avg The calculation method is as follows:

[0023]

[0024] in, T is the statistical window, and t is the sampling period;

[0025] The flow deviation Δ is calculated as follows:

[0026]

[0027] Among them, WF l The lower limit is WF h This is the upper limit.

[0028] The preferred method for adjusting the water flow rate is as follows:

[0029]

[0030] Among them, VO i-1 To adjust the opening degree of the valve for regulating water flow at the previous moment, VO i The valve opening is used to adjust the water flow rate.

[0031] This invention also provides a protection and control device for CAFS output pressure. The device includes an air pipeline, a fire water pipeline, and a foam liquid pipeline. One end of the air pipeline is connected to an air compressor unit, and the other end is connected to the first input terminal of a gas-liquid mixer. One end of the fire water pipeline is connected to a water tank, and the other end is connected to the first input terminal of a liquid-liquid mixer. One end of the foam liquid pipeline is connected to a foam liquid tank, and the other end is connected to the second input terminal of the liquid-liquid mixer. The output terminal of the liquid-liquid mixer is connected to the second input terminal of the gas-liquid mixer, and the output terminal of the gas-liquid mixer is connected to a release device. A bypass regulating valve and a first flow meter are installed on the air pipeline. A water pump unit, a first valve, and a second flow meter are installed on the fire water pipeline. A second valve, a foam pump unit, and a third flow meter are installed on the foam liquid pipeline. A main outlet valve and a pressure gauge are installed between the output terminal of the gas-liquid mixer and the release device.

[0032] Preferably, the air flow rate, water flow rate, and foam liquid flow rate are collected by the first flow meter, the second flow meter, and the third flow meter, respectively; the output pressure is collected by the pressure gauge; the water flow rate is adjusted by adjusting the first valve; the air-liquid ratio is adjusted by adjusting the bypass regulating valve; and the foam liquid mixing ratio is adjusted by adjusting the foam pump unit.

[0033] Preferably, the device further includes a PLC controller, with the flow meter and pressure gauge connected to the analog signal input terminal of the PLC controller, and the analog signal output terminal of the PLC controller connected to the bypass regulating valve, the valve, the foam pump unit, and the water pump unit.

[0034] The advantages provided by this invention are: the CAFS output pressure protection and control method of this invention has a high degree of automation, requires no manual operation, can be implemented by software logic functions, is easy to control, does not increase hardware costs, and is highly implementable. Attached Figure Description

[0035] Figure 1 The control logic diagram of the CAFS output pressure protection control method provided in the embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a CAFS output pressure protection and control device provided in an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of the signal ports of the PLC controller in the CAFS output pressure protection and control device provided in this embodiment of the invention;

[0038] In the diagram: 10 Air pipeline, 11 Air compressor unit, 12 Bypass regulating valve, 13 First flow meter, 14 Silencer, 20 Fire water pipeline, 21 Water tank, 22 Water pump unit, 23 First valve, 24 Second flow meter, 30 Foam liquid pipeline, 31 Foam liquid tank, 32 Second valve, 33 Foam pump unit, 34 Third flow meter, 41 Gas-liquid mixer, 42 Liquid-liquid mixer, 43 Main outlet valve, 44 Pressure gauge. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] Example 1

[0041] like Figure 1As shown, this embodiment provides a protection and control method for CAFS output pressure, which includes the following steps:

[0042] S1. Set pressure protection limits, including high start value, high alarm value, high protection value, low start value, low alarm value and low protection value; collect output pressure, water flow rate, foam liquid flow rate and air flow rate; calculate gas-liquid ratio and foam liquid mixing ratio.

[0043] S2. When the output pressure is greater than the low start value and less than the high start value, proceed to step S7; when the output pressure is greater than the high start value, proceed to step S3; when the output pressure is less than the low start value, proceed to step S5.

[0044] S3. Keep the water flow rate constant and determine whether the output pressure is greater than the high alarm value. If so, reduce the air flow rate until the gas-liquid ratio reaches the lower limit value and proceed to S4. If not, proceed to S7.

[0045] S4. Determine if the output pressure is greater than the high protection value. If so, reduce the water flow until the output pressure is less than the high alarm value, and simultaneously adjust the foam liquid flow until the foam liquid mixing ratio reaches the mixing ratio set value. If not, proceed to step S7.

[0046] S5. Keep the water flow rate constant and determine whether the output pressure is lower than the low alarm value. If yes, increase the air flow rate until the gas-liquid ratio reaches the upper limit value and proceed to step S6. If no, proceed to step S7.

[0047] S6. Determine if the output pressure is less than the low protection value. If yes, increase the water flow until the output pressure is greater than the low alarm value, and simultaneously adjust the foam liquid flow until the foam liquid mixing ratio reaches the mixing ratio set value. If no, proceed to step S7.

[0048] S7. Adjust the water flow rate until the water flow rate meets the preset conditions, which are between the lower and higher limits.

[0049] The order of pressure protection limits is as follows: High protection value > High alarm value > High start value > Low start value > Low alarm value > Low protection value.

[0050] The gas-liquid ratio R is calculated as follows:

[0051]

[0052] Where F1 is the water flow rate, F2 is the foam liquid flow rate, and F3 is the air flow rate.

[0053] The gas-liquid ratio R refers to the ratio of air volume (converted to normal temperature and pressure) to the volume of the foam mixture. This ratio can be adjusted by regulating the airflow rate; increasing the airflow rate increases the gas-liquid ratio, and vice versa. This invention uses a bypass regulating valve on the air pipeline. Air enters through the first port of the valve, the second port is connected to the input of the gas-liquid mixer, and the third port is connected to the atmosphere through a silencer. In the gas-liquid mixer, air and foam mixture are combined. The gas-liquid ratio is adjusted by changing the opening of the bypass regulating valve. Decreasing the valve opening increases the amount of compressed air entering the mixer, resulting in a larger gas-liquid ratio; conversely, increasing the valve opening decreases the amount of compressed air entering the mixer, resulting in a smaller gas-liquid ratio.

[0054] The mixing ratio H of the foam liquid is calculated as follows:

[0055]

[0056] Where F1 is the water flow rate and F2 is the foam liquid flow rate.

[0057] The total output flow rate is the sum of the water flow rate, foam liquid flow rate, and air flow rate, and is approximately equal to the water flow rate. Therefore, by adjusting the water flow rate, the total output flow rate can be adjusted. This invention can achieve the adjustment of reducing the water flow rate in step S4 and increasing the water flow rate in step S6 by adjusting the opening of the valves on the fire water pipeline. Simultaneously, based on the foam liquid mixing ratio set value, the foam pump speed on the foam liquid pipeline is adjusted to regulate the foam liquid flow rate until the foam liquid mixing ratio reaches the set value.

[0058] In step S7, during the adjustment of water flow, it is determined whether the average water flow within the statistical window T meets the preset conditions. If the conditions are met, the water flow adjustment function is locked; if the conditions are not met, the flow deviation Δ is calculated, and the water flow is adjusted. When the average fire water flow in the statistical period window is lower than the lower limit of the fire water flow setting, an increase adjustment command is output; when the average flow is higher than the upper limit of the setting, a decrease adjustment command is output; when the average flow is between the upper and lower limits, the flow adjustment command is locked.

[0059] Average water flow rate WF avg The calculation method is as follows:

[0060]

[0061] in, T is the statistical window, and t is the sampling period;

[0062] The flow deviation α is calculated as follows:

[0063]

[0064] Among them, WF l The lower limit is WF h This is the upper limit.

[0065] The method for adjusting the water flow is as follows:

[0066]

[0067] Among them, VO i-1 To adjust the opening degree of the valve for regulating water flow at the previous moment, VO i The valve opening is used to adjust the water flow rate.

[0068] When a compressed air foam fire extinguishing system is in operation, if the type or number of terminal release devices changes, relying solely on the flow rate and head characteristics of the fire pump for passive adjustment may result in situations where the output pressure is too high, causing the air compressor to depressurize, or the output pressure is too low, resulting in insufficient range. To address this issue, this invention achieves multi-stage pressure control by setting high start-up values, high alarm values, high protection values, low start-up values, low alarm values, and low protection values. This allows for tiered processing before the pressure reaches the equipment's protection shutdown threshold. When the output pressure exceeds the high start-up value or falls below the low start-up value, the water flow rate remains constant, and this first-stage action locks in reverse flow regulation to prevent further pressure increases or decreases, thus avoiding exceeding the equipment's normal operating range. When the output pressure exceeds the high alarm value or falls below the low alarm value, the air flow rate is adjusted, thereby regulating the gas-liquid ratio. The second-stage action adjusts the gas-liquid ratio to maintain the flow rate and prevent a decrease in fire extinguishing capacity. When the output pressure is greater than the high protection value or less than the low protection value, the water flow rate is adjusted and the foam liquid flow rate is adjusted simultaneously. The third-stage action adjusts the flow rate to the second-stage alarm value while implementing the first two stages. This maximizes the output flow rate and fire extinguishing capacity while maintaining system operation, thereby achieving automatic protection of the compressed air foam fire extinguishing system output pressure. When the system output pressure is too high or too low, it can actively adjust, improving the stability and safety of system operation.

[0069] The CAFS output pressure protection and control method of this invention has a high degree of automation, requires no manual operation, can be implemented by software logic functions, is easy to control, does not increase hardware costs, and is highly feasible.

[0070] Example 2

[0071] See Figure 2This embodiment provides a protection and control device for CAFS output pressure, employing the CAFS output pressure protection and control method of Embodiment 1. The device includes an air pipeline 10, a fire water pipeline 20, and a foam liquid pipeline 30. One end of the air pipeline 10 is connected to the air compressor unit 11, and the other end is connected to the first input terminal of the gas-liquid mixer 41. One end of the fire water pipeline 20 is connected to the water tank 21, and the other end is connected to the first input terminal of the liquid-liquid mixer 42. One end of the foam liquid pipeline 30 is connected to the foam liquid tank 31, and the other end is connected to the second input terminal of the liquid-liquid mixer 42. The output of the liquid-liquid mixer 42... The air pipeline 10 is connected to the second input end of the gas-liquid mixer 41, and the output end of the gas-liquid mixer 41 is connected to the compressed air foam release device. A bypass regulating valve 12 and a first flow meter 13 are installed on the air pipeline 10. Air is introduced into the first port of the bypass regulating valve 12, the second port is connected to the input end of the gas-liquid mixer 41, and the third port is connected to the atmospheric environment through a silencer 14. A water pump unit 22, a first valve 23, and a second flow meter 24 are installed on the fire water pipeline 20. A second valve 32, a foam pump unit 33, and a third flow meter 34 are installed on the foam liquid pipeline 30. A main outlet valve 43 and a pressure gauge 44 are installed between the output end of the gas-liquid mixer 41 and the release device. The compressed air foam release device includes a fire monitor, a robot, and a spray pipe. In this embodiment, the air compressor unit 11 includes a main air compressor and a standby air compressor, the water pump unit 22 includes a main water pump and a standby water pump, and the foam pump unit 33 includes a main foam pump and a standby foam pump.

[0072] Air flow is collected by the first flow meter 13 on the air pipeline 10, water flow is collected by the second flow meter 24 on the fire water pipeline 20, foam liquid flow is collected by the third flow meter 34 on the foam liquid pipeline 30, output pressure is collected by the pressure gauge 44, water flow is adjusted by adjusting the first valve 23 on the fire water pipeline, air-liquid ratio is adjusted by adjusting the bypass regulating valve 12, and foam liquid mixing ratio is adjusted by adjusting the foam pump unit 33.

[0073] See Figure 3 The device also includes a PLC controller. The first flow meter 13, the second flow meter 24, the third flow meter 34, and the pressure gauge 44 are connected to the analog signal input terminals of the PLC controller, and the analog signal output terminals of the PLC controller are connected to the bypass regulating valve 12 and the first valve 23, respectively. The PLC controller collects the values ​​from the first flow meter 13, the second flow meter 24, the third flow meter 34, and the pressure gauge 44 to obtain the output pressure and output flow rate. The output flow rate is the sum of the water flow rate, the foam liquid flow rate, and the air flow rate, approximating the water flow rate. When the output pressure P is greater than the low start value P... ls And less than the high start-up value P hsAt that time, the water flow rate is adjusted by regulating the first valve 23 on the fire water pipeline. When the output pressure P is greater than the high start value P hs And below the high alarm value P hw At this time, the first valve 23 is not adjusted. The water flow rate increase adjustment command is blocked, and the output pressure P is judged. When the output pressure P is greater than the high alarm value P hw When the bypass regulating valve 12 is opened, the air flow rate and the gas-liquid ratio are reduced until the bypass regulating valve 12 reaches its upper limit. At this point, the gas-liquid ratio reaches its lower limit. By adjusting the air flow rate, the output pressure is regulated, ensuring that the output pressure is reduced without adjusting the water flow rate. This maintains the flow rate and prevents a decrease in fire extinguishing capacity. When the output pressure exceeds the high protection value P... he At this time, while keeping the opening of the bypass regulating valve 12 at its upper limit, the water flow rate is reduced by adjusting the first valve 23. Simultaneously, the speed of the foam pump is adjusted according to the foam liquid mixing ratio set value to reduce the foam liquid flow rate, so as to keep the foam liquid mixing ratio H constant, until the output pressure is lower than the high alarm value P. hw To maximize output flow and fire suppression capabilities while maintaining system operation.

[0074] The formula for adjusting the opening VB of the bypass regulating valve 12 is as follows:

[0075]

[0076] The formula for adjusting the opening VO of the first valve 23 is as follows:

[0077]

[0078] When the output pressure P is less than the low starting value P ls And greater than the low alarm value P lw At this time, the first valve 23 is not adjusted. The water flow reduction adjustment command is blocked, and the output pressure P is judged. When the output pressure P is less than the low alarm value P lw When the bypass regulating valve 12 is closed, the air flow rate is increased, and the gas-liquid ratio is increased until the bypass regulating valve 12 reaches its lower limit. At this point, the gas-liquid ratio reaches its upper limit. The output pressure is regulated by adjusting the air flow rate, ensuring that the output pressure is reduced without adjusting the water flow rate. When the output pressure is lower than the low protection value P... le At this time, while keeping the opening of the bypass regulating valve 12 unchanged at the lower limit, the water flow rate is increased by adjusting the first valve 23. Simultaneously, the speed of the foam pump is adjusted according to the foam liquid mixing ratio set value to increase the foam liquid flow rate, so as to keep the foam liquid mixing ratio H unchanged, until the output pressure is greater than the high alarm value P. lw .

[0079] The formula for adjusting the opening VB of the bypass regulating valve 12 is as follows:

[0080]

[0081] The formula for adjusting the opening VO of the first valve 23 is as follows:

[0082]

[0083] In practical operation, the PLC controller acquires status signals from devices such as the first valve, second valve, water pump unit, and air compressor unit via the DI terminal, and outputs control signals via the DO terminal to open and close the first and second valves, and start and stop the water pump unit and air compressor unit. It acquires analog signals such as flow rate, pressure, and liquid level via the AI ​​terminal, and outputs signals such as mixed liquid flow rate and system pressure via the AO terminal. When the CAFS output pressure protection control device receives the start command for the compressed air foam fire extinguishing system, it opens the valves on each pipeline according to the start sequence, starts the air compressor unit, foam pump unit, and water pump unit, and puts the system into operation.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protection and control method for CAFS output pressure, characterized in that: The methods include: S1. Set pressure protection limits, including high start value, high alarm value, high protection value, low start value, low alarm value and low protection value; collect output pressure, water flow rate, foam liquid flow rate and air flow rate; calculate gas-liquid ratio and foam liquid mixing ratio. S2. When the output pressure is greater than the low start value and less than the high start value, proceed to step S7; when the output pressure is greater than the high start value, proceed to step S3; when the output pressure is less than the low start value, proceed to step S5. S3. Keep the water flow rate constant and determine whether the output pressure is greater than the high alarm value. If so, reduce the air flow rate until the gas-liquid ratio reaches the lower limit value and proceed to S4. If not, proceed to S7. S4. Determine if the output pressure is greater than the high protection value. If so, reduce the water flow until the output pressure is less than the high alarm value, and simultaneously adjust the foam liquid flow until the foam liquid mixing ratio reaches the mixing ratio set value. If not, proceed to step S7. S5. Keep the water flow rate constant and determine whether the output pressure is lower than the low alarm value. If yes, increase the air flow rate until the gas-liquid ratio reaches the upper limit value and proceed to step S6. If no, proceed to step S7. S6. Determine if the output pressure is less than the low protection value. If yes, increase the water flow until the output pressure is greater than the low alarm value, and simultaneously adjust the foam liquid flow until the foam liquid mixing ratio reaches the mixing ratio set value. If no, proceed to step S7. S7. Adjust the water flow rate until the water flow rate meets the preset conditions, which are between the lower and higher limits.

2. The protection and control method for CAFS output pressure according to claim 1, characterized in that: The gas-liquid ratio R is calculated as follows: Where F1 is the water flow rate, F2 is the foam liquid flow rate, and F3 is the air flow rate.

3. The protection and control method for CAFS output pressure according to claim 1, characterized in that: The mixing ratio H of the foam liquid is calculated as follows: Where F1 is the water flow rate and F2 is the foam liquid flow rate.

4. The protection and control method for CAFS output pressure according to claim 1, characterized in that: The order of pressure protection limits is as follows: High protection value > High alarm value > High start value > Low start value > Low alarm value > Low protection value.

5. The protection and control method for CAFS output pressure according to claim 1, characterized in that: The process of adjusting water flow is as follows: determine whether the average water flow within the statistical window T meets the preset conditions. If the conditions are met, lock the water flow adjustment function. If the conditions are not met, calculate the flow deviation Δ and adjust the water flow.

6. The protection and control method for CAFS output pressure according to claim 5, characterized in that: Average water flow rate WF avg The calculation method is as follows: in, T is the statistical window, and t is the sampling period; The flow deviation Δ is calculated as follows: Among them, WF l The lower limit is WF h This is the upper limit.

7. The protection and control method for CAFS output pressure according to claim 5, characterized in that: The method for adjusting the water flow is as follows: Among them, VO i-1 To adjust the opening degree of the valve for regulating water flow at the previous moment, VO i The valve opening is used to adjust the water flow rate.

8. A protection and control device for CAFS output pressure, employing the protection and control method described in any one of claims 1-7, characterized in that: The device includes an air pipeline, a fire water pipeline, and a foam liquid pipeline. One end of the air pipeline is connected to an air compressor unit, and the other end is connected to the first input terminal of a gas-liquid mixer. One end of the fire water pipeline is connected to a water tank, and the other end is connected to the first input terminal of a liquid-liquid mixer. One end of the foam liquid pipeline is connected to a foam liquid tank, and the other end is connected to the second input terminal of a liquid-liquid mixer. The output terminal of the liquid-liquid mixer is connected to the second input terminal of a gas-liquid mixer, and the output terminal of the gas-liquid mixer is connected to a release device. A bypass regulating valve and a first flow meter are installed on the air pipeline. A water pump unit, a first valve, and a second flow meter are installed on the fire water pipeline. A second valve, a foam pump unit, and a third flow meter are installed on the foam liquid pipeline. A main outlet valve and a pressure gauge are installed between the output terminal of the gas-liquid mixer and the release device.

9. The CAFS output pressure protection and control device according to claim 8, characterized in that: The air flow rate, water flow rate, and foam liquid flow rate are collected by the first flow meter, the second flow meter, and the third flow meter, respectively. The output pressure is collected by the pressure gauge. The water flow rate is adjusted by adjusting the first valve. The air-liquid ratio is adjusted by adjusting the bypass regulating valve. The foam liquid mixing ratio is adjusted by adjusting the foam pump unit.

10. The CAFS output pressure protection and control device according to claim 8, characterized in that: The device also includes a PLC controller. The flow meter and pressure gauge are connected to the analog signal input terminal of the PLC controller, and the analog signal output terminal of the PLC controller is connected to the bypass regulating valve, valve, foam pump unit, and water pump unit.

Images