Automatic foam flushing device and control method thereof

Abstract

The invention relates to the technical field of fire fighting equipment, in particular to an automatic foam flushing device and a control method of the automatic foam flushing device. The automatic foam flushing device comprises a controller, a water outlet valve, a water pump, a drain valve, a foam guide valve, a Venturi tube, a flow regulating valve, a flow switch, a foam liquid outlet valve and a flushing power device; the foam tank, the foam liquid outlet valve, the flow switch and the flow regulating valve are connected in sequence and are connected to the negative pressure suction end of the Venturi tube; the water tank, the water outlet valve, the water pump and the drain valve are sequentially communicated; the controller is in signal connection with the water outlet valve, the water pump, the drainage valve, the foam guide valve, the flow adjusting valve, the flow switch, the foam liquid outlet valve and the flushing power device. The control method comprises the steps that the controller reads a signal of the flow switch in real time, waits for flushing and executes the flushing function. The automatic flushing function is achieved, and corrosion damage, caused by foam accumulation, of pipelines or pipeline equipment due to forgetting of firemen is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of fire-fighting equipment, and in particular to an automatic foam flushing device and a control method for the automatic foam flushing device. Background Art

[0002] Currently, all foam fire trucks have different types of flushing devices, usually a flushing valve. Once the foam is extinguished, firefighters open the flushing valve, attach a power take-off (PTO) to drive the water pump, and simultaneously open the outlet valve to drain any remaining foam. Once the firefighter visually detects no more foam flowing out, they remove the PTO, stop the water pump, and close the outlet valve.

[0003] This setting has the following conditions: (1) Flushing needs to be started manually. Firefighters tend to forget to flush after using foam, which will cause the corrosive foam liquid to accumulate in the pipeline, causing damage to the pipeline, valves and other sensors.

[0004] (2) The entire flushing process requires the use of a power take-off (PTO) as a power source, and the water outlet needs to be opened. After the flushing is completed, the PTO needs to be removed and the water outlet needs to be manually closed. At the same time, the PTO can only be attached and detached when the vehicle is parked, which limits the use of pipeline flushing scenarios. The entire flushing process is very cumbersome.

[0005] (3) During the flushing process, although some foam is discharged from the water outlet, some foam liquid still flows into the foam pipeline along the flushing valve. At the same time, most of the water in the flushing device flushes the pump pipeline, and a small part of the water flushes the foam pipeline, resulting in a huge waste of water system.

[0006] (4) Flushing requires firefighters to manually shut down the system, and they need to visually inspect the liquid being flushed to see if it contains foam. Due to the inconsistency of the outlet method and pressure, it is difficult to visually inspect whether the liquid has been flushed clean or whether excessive flushing has resulted in waste. Summary of the Invention

[0007] The object of the present invention is to provide a foam automatic flushing device and a control method for the foam automatic flushing device, which can solve the above technical problems.

[0008] In a first aspect, the present invention provides an automatic foam flushing device suitable for a foam system of a fire truck, comprising a water tank and a foam tank, which also includes a controller, a water outlet valve, a water pump, a drain valve, a foam inlet valve, a venturi tube, a flow regulating valve, a flow switch, a foam outlet valve, and a flushing power device; The water outlet valve is provided at the input end of the water pump and is used to control the communication state between the water pump and the water tank; The foam tank, the foam outlet valve, the flow switch and the flow regulating valve are connected in sequence, and the output end of the flow regulating valve is connected to the negative pressure suction end of the venturi tube; The water tank, the water outlet valve, the water pump and the drain valve are connected in sequence; The high-pressure water inlet of the venturi tube is connected to the output end of the foam induction valve, and the input end of the foam induction valve is connected between the water pump and the drain valve; The mixed liquid outlet of the venturi tube is connected between the water outlet valve and the water pump; The input end of the flushing power device is connected between the water tank and the water outlet valve, and the output end of the flushing power device is connected between the foam outlet valve and the flow switch; The controller is respectively connected to the water outlet valve, the water pump, the drain valve, the foam inducing valve, the flow regulating valve, the flow switch, the foam outlet valve and the flushing power device by signal.

[0009] In a preferred embodiment, a first conductivity sensor is provided at the input end of the drain valve, and a second conductivity sensor is provided on the water tank.

[0010] In a preferred embodiment, the flushing power device is an electric flushing pump.

[0011] In a preferred embodiment, a flushing valve is provided at the output end of the flushing power device, and the output end of the flushing valve is connected between the foam outlet valve and the flow switch.

[0012] In a preferred embodiment, a one-way valve is provided at the output end of the flushing valve, and the output end of the one-way valve is connected between the foam outlet valve and the flow switch.

[0013] In a second aspect, the present invention further provides a control method for the automatic foam flushing device described in any one of the above items, wherein the controller reads the signal of the flow switch in real time, and when the flow switch detects the flow signal, wakes up the flushing function and waits for flushing; When the flow rate of the flow switch is zero and lasts for a first set time, and the water outlet pressure of the water pump is less than a set value, the flushing function is executed.

[0014] In a preferred embodiment, when the flushing function is performed, the controller controls the opening of the flow regulating valve to perform periodic adjustment.

[0015] In a preferred embodiment, the output end of the flushing power device is provided with a second pressure sensor, and the water outlet of the water pump is provided with a first pressure sensor; The pressure value of the second pressure sensor is smaller than the pressure value of the first pressure sensor.

[0016] In a preferred embodiment, when the conductivity detected at the input end of the drain valve is the same as the conductivity detected in the water tank, or the error is within a set range, the flushing power device is turned off.

[0017] In a preferred embodiment, when the flushing power device is turned off, the drain valve remains open, and after a second set time, the controller closes the drain valve.

[0018] The beneficial effects of the embodiments of the present invention are: By detecting the flow switch, the flushing function is automatically awakened and when the set conditions are met, the flushing power device is started and the flushing process is executed, thereby realizing the automatic flushing function and avoiding corrosion damage to pipelines or pipeline equipment caused by foam accumulation due to firefighters' forgetfulness. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without making any creative efforts.

[0020] Figure 1 A schematic diagram of an automatic foam flushing device provided by an embodiment of the present invention; Figure 2 A control logic diagram of the automatic foam flushing device provided by an embodiment of the present invention; Figure 3 This is a flowchart of the use of the automatic foam flushing device provided in an embodiment of the present invention.

[0021] Icons: 1-water tank; 2-foam tank; 3-water pump; 4-electric flushing pump; 5-venturi tube; 6-water outlet valve; 7-foam outlet valve; 8-flow regulating valve; 9-flow switch; 10-foam inlet valve; 11-drain valve; 12-flush valve; 13-check valve; 14-first conductivity sensor; 15-second conductivity sensor; 16-first pressure sensor; 17-second pressure sensor. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0025] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like indicate positions or locations based on the positions shown in the accompanying drawings, or the positions or locations in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0027] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0028] The following combination Figure 1-Figure 3, some embodiments of the present invention are described in detail. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] In the first aspect, the present invention provides an automatic foam flushing device suitable for a fire truck foam system, comprising a water tank 1 and a foam tank 2, such as Figure 1 As shown, it also includes a controller, a water outlet valve 6, a water pump 3, a drain valve 11, a foam induction valve 10, a venturi tube 5, a flow regulating valve 8, a flow switch 9, a foam outlet valve 7 and a flushing power device; the water outlet valve 6 is arranged at the input end of the water pump 3, and is used to control the connection state between the water pump 3 and the water tank 1; the foam tank 2, the foam outlet valve 7, the flow switch 9 and the flow regulating valve 8 are connected in sequence, and the output end of the flow regulating valve 8 is connected to the negative pressure suction end of the venturi tube 5; the water tank 1, the water outlet valve 6, the water pump 3 and the drain valve 11 are connected in sequence; the venturi tube The high-pressure water inlet of 5 is connected to the output end of the foam induction valve 10, and the input end of the foam induction valve 10 is connected between the water pump 3 and the drain valve 11; the mixed liquid outlet of the venturi tube 5 is connected between the water outlet valve 6 and the water pump 3; the input end of the flushing power device is connected between the water tank 1 and the water outlet valve 6, and the output end of the flushing power device is connected between the foam outlet valve 7 and the flow switch 9; the controller is respectively connected to the outlet valve 6, the water pump 3, the drain valve 11, the foam induction valve 10, the flow regulating valve 8, the flow switch 9, the foam outlet valve 7 and the flushing power device signal.

[0030] In this embodiment, after the fire truck completes the foam fire extinguishing task, the controller automatically starts the flushing process based on the signals fed back by each component.

[0031] Specifically, in this embodiment, the water outlet valve 6 is connected to the water tank 1 through the water pump 3 to ensure the supply of flushing water; the foam valve 10 is introduced in conjunction with the venturi tube 5 to achieve sufficient mixing of foam and water; the flow regulating valve 8 and the flow switch 9 cooperate to monitor and control the foam flow and trigger the flushing wake-up function; the flushing power device provides the power required for flushing, and the position design of its output end can directly send the flushing water into the foam pipeline to achieve targeted flushing; the controller monitors the status of each component in real time through signal connection, realizes automatic control of the flushing process, avoids the tedious and forgetful problems of manual operation by firefighters, effectively prevents pipelines and equipment from being damaged due to foam backlog, and improves the reliability and service life of fire trucks.

[0032] In this embodiment, when foam fire extinguishing is complete, flow switch 9 detects zero flow, and the outlet pressure of water pump 3 remains below a set value for a specified period, the controller determines that the flushing conditions are met and activates the flushing function. The flushing power unit activates, closing outlet valve 6. Water from tank 1 is then fed exclusively into the foam pipeline via the flushing power unit, flushing any residual foam from the pipeline walls and various connections. Simultaneously, the controller adjusts the opening of flow control valve 8, ensuring a reciprocating flow of water to flush any blind spots in the pipeline, ensuring a thorough flush.

[0033] The entire flushing process is automatically controlled by the controller based on preset logic and sensor feedback signals, without the need for human intervention, thus achieving automation and efficiency in the flushing of the fire truck's foam system.

[0034] In this embodiment, the flow control valve 8 can adopt different types of valves, such as an electric control valve or a pneumatic control valve, as long as it can achieve precise control of the flow. However, different types of valves may have differences in response speed and control accuracy.

[0035] In a preferred embodiment, a first conductivity sensor 14 is provided at the input end of the drain valve 11 , and a second conductivity sensor 15 is provided on the water tank 1 .

[0036] In this embodiment, a first conductivity sensor 14 is provided at the input end of the drain valve 11 for real-time monitoring of the conductivity of the liquid at the drain outlet. A second conductivity sensor 15 is also provided on the water tank 1 for detecting the conductivity of the water within the water tank 1. Both the first and second conductivity sensors 14, 15 are signal-connected to a controller and transmit the detected conductivity data to the controller in real time.

[0037] Specifically, the signal connection method can be a wired connection or a wireless connection.

[0038] Water has a relatively low and stable conductivity, while foam contains various chemical components, causing its conductivity to differ significantly from that of water. Once the remaining foam in the pipe is flushed away, the liquid discharged from the drain is essentially water, and the conductivity changes accordingly. By comparing the conductivity at the drain and at tank 1, it is possible to accurately determine whether the flush is complete.

[0039] The controller pre-sets the conductivity error range and executes the flushing end command when the actual measured value meets the conditions. This setting method has high accuracy and sensitivity, can effectively adapt to the flushing needs of different foam compositions and water quality conditions, and improve the intelligent level of the flushing device.

[0040] During the flushing process, the liquid discharged from the drain port is a mixture of foam and water. As the flushing proceeds, the foam component is gradually washed away, and the conductivity of the discharged liquid gradually approaches the conductivity of the water in the water tank 1.

[0041] When the conductivity of the drain outlet detected by the first conductivity sensor 14 is the same as the conductivity of the water tank 1 detected by the second conductivity sensor 15 or the error is within the set range, it indicates that the flushing has achieved the expected effect and the foam residue in the pipeline has been fully removed.

[0042] At this time, the controller shuts down the flushing power device based on the conductivity signal and stops flushing, effectively avoiding water waste and equipment wear caused by excessive flushing, while ensuring the reliability and consistency of the flushing effect.

[0043] It can be understood that in this embodiment, a conductivity sensor is used to determine whether the foam is rinsed clean, but it is not limited to the conductivity sensor. Other detection methods can also be used, such as a refractive index sensor. The refractive index of the liquid can be detected to distinguish between water and foam mixtures. In other words, as long as it can be determined whether the water outlet contains foam when the water is discharged, it will be sufficient.

[0044] In a preferred embodiment, the flushing power device is an electric flushing pump 4 .

[0045] In this embodiment, the electric flushing pump 4 is driven by a motor, has an independent power supply system and control circuit, is connected to the controller, and receives start, stop and speed adjustment instructions from the controller.

[0046] Specifically, in this embodiment, the electric flushing pump 4 can extract water from the water tank 1 and deliver it to the foam pipeline through its output end, generating sufficient water pressure and flow to flush residual foam on the inner wall of the pipeline and various connection points. Compared with the traditional method of using a power take-off to drive the water pump 3, the electric flushing pump 4 is not restricted by the vehicle's driving state. Whether the vehicle is parked or driving, as long as there is water in the water tank 1 and the circuit is normal, the flushing operation can be initiated. This greatly improves the applicable scenarios and flexibility of the flushing, meets the flushing needs under different working conditions, and ensures that the fire truck is in good working condition at all times.

[0047] When the controller issues a flush command, the motor of electric flush pump 4 is energized and activated, driving the internal impeller to rotate, generating centrifugal force. Water in water tank 1 is drawn into the pump body under the action of centrifugal force and flows out of the output end at high speed, forming a water flow with a certain pressure and flow rate. By controlling the speed of the motor, the output pressure and flow rate of water pump 3 can be adjusted to meet different flushing requirements.

[0048] During the flushing process, water circulates in the pipes, using the water's impact and turbulence to flush away any residual foam adhering to the pipe walls and discharge it out of the vehicle through drain valve 11. Furthermore, the independent power supply and control of the electric flushing pump 4 makes it independent of the vehicle's travel system, ensuring a stable and safe flushing process.

[0049] It can be understood that in this embodiment, the flushing power device is an electric flushing pump 4, but it is not limited to the electric flushing pump 4. It can also be other devices that can provide power for flushing, such as a pneumatic flushing pump, which uses the pressure of compressed air to press the water in the water tank 1 into the pipeline for flushing. In other words, as long as it can provide power for flushing, it will be fine.

[0050] In a preferred embodiment, a flushing valve 12 is provided at the output end of the flushing power device, and the output end of the flushing valve 12 is connected between the foam outlet valve 7 and the flow switch 9 .

[0051] In this embodiment, a flushing valve 12 is provided at the output of the flushing power unit, communicating between the foam outlet valve 7 and the flow switch 9. Flushing valve 12, a controllable valve such as a solenoid valve or an electric valve, is installed on the output pipeline of the flushing power unit and connected to a controller, receiving valve opening and closing commands from the controller.

[0052] In this embodiment, the primary function of flush valve 12 is to control the flow of water into the foam pipeline during the flushing process. When the controller determines that the flushing conditions are met and activates the flushing function, flush valve 12 opens, activating the flushing function and allowing the electric flushing pump 4 to immediately input the output water flow into the pipeline between the foam outlet valve 7 and the flow switch 9 to begin flushing the foam pipeline.

[0053] After the flushing is completed, the controller issues a command to close the flush valve 12, preventing water from continuing to enter the pipeline, thereby preventing unnecessary water waste and other problems that may be caused by water accumulation in the pipeline. Through the precise control of the flush valve 12, the flushing process is carried out in an orderly manner, and the automation and accuracy of the flushing operation are improved.

[0054] In a preferred embodiment, a one-way valve 13 is provided at the output end of the flushing valve 12 , and the output end of the one-way valve 13 is connected between the foam outlet valve 7 and the flow switch 9 .

[0055] In this embodiment, a one-way valve 13 is provided at the output end of the flushing valve 12 , and the output end of the one-way valve 13 is connected between the foam outlet valve 7 and the flow switch 9 .

[0056] Specifically, in this embodiment, the main function of the one-way valve 13 is to prevent the liquid in the pipeline from flowing back, to avoid the foam output by the foam tank 2 from flowing back into the water tank 1 during the fire extinguishing process, causing pollution of the water in the water tank 1, and to prevent the water from flowing back to the flushing device after the flushing is completed due to factors such as changes in pipeline pressure, thereby affecting the normal operation and service life of the equipment.

[0057] The presence of the one-way valve 13 ensures the one-way flow of water during the flushing process, ensures the efficiency and cleanliness of the flushing process, and improves the reliability and stability of the entire flushing system.

[0058] In this embodiment, a one-way valve 13 is used to limit backflow, but it is not limited to the one-way valve 13. It can also be other valve bodies with similar functions. For example, a check valve can be used as an alternative to prevent backflow. In other words, as long as it can prevent foam from flowing back into the water tank 1, it will be sufficient.

[0059] In a second aspect, the present invention further provides a method for controlling the automatic foam flushing device according to any one of the above items, such as Figure 3 As shown, the controller reads the signal of the flow switch 9 in real time. When the flow switch 9 detects the flow signal, the flushing function is awakened and waits for flushing; when the flow of the flow switch 9 is zero and lasts for the first set time, and the outlet pressure of the water pump 3 is less than the set value, the flushing function is executed.

[0060] In this embodiment, the controller is the core component, connected to the flow switch 9, water pump 3 and other components, and monitors the signal of the flow switch 9 in real time to realize the awakening and execution of the flushing function. The flow switch 9 is installed in the foam pipeline to detect the flow change of the foam.

[0061] Specifically, in this embodiment, during the foam fire extinguishing process of the fire truck, when the foam flows through the flow switch 9, the flow switch 9 detects the flow signal and transmits it to the controller. After receiving the signal, the controller wakes up the flushing function, that is, opens the flushing valve 12, and puts the electric flushing pump 4 in a standby state, ready to perform the flushing operation at any time. When the fire extinguishing task is completed, the foam flow gradually decreases until it reaches zero, that is, the flow switch 9 signal is lost, and this state lasts for a first set time, such as 30s. At the same time, when the outlet pressure of the water pump 3 is less than the set value, such as 0.5Mpa, the controller determines that the foam delivery is completed. At this time, the flushing execution condition is met, and the controller issues a command to start the electric flushing pump 4. The electric flushing pump 4 begins to automatically flush the pipeline without the need for manual operation by firefighters, effectively avoiding equipment damage caused by pipeline failure due to human negligence, and improving the maintenance efficiency and safety of the fire truck.

[0062] Specifically, during the operation of the water pump 3, when the foam pipeline detects the foam flow, the flushing function is awakened and the foam output is completed.

[0063] When the flow switch 9 detects a loss of signal, the foaming process is concluded. The outlet pressure sensor also measures whether the system is in the high-pressure water delivery phase, preventing pump 3 system deviation or instability caused by flushing during high-speed, high-pressure water delivery. The control system automatically activates the flushing function after the flow switch 9 signal is lost and the outlet pressure is less than 0.5 MPa for 30 seconds.

[0064] When flushing is activated, the system automatically opens flush valve 12 and drain valve 11, activating the flushing pump and controlling its speed. The flushing pump outlet pressure is controlled to be no higher than 0.5 MPa. When the chassis power take-off is detected via the CAN bus and the outlet pressure is greater than 0.2 MPa, indicating that water pump 3 is operating, the flushing pump line pressure must be controlled to be less than or equal to 0 MPa to prevent the backflow of the flushing foam into water tank 1. If outlet valve 6 is detected to be closed, preventing the flushing mixture from backflowing into water tank 1, the flushing volume can be increased, raising the flushing outlet limit to 0.5 MPa.

[0065] In a preferred embodiment, when the flushing function is executed, the controller controls the opening of the flow regulating valve 8 to perform periodic adjustment.

[0066] In this embodiment, the flow regulating valve 8 is installed in the foam pipeline to control the flow rate of water and is connected to the controller to receive the adjustment command signal issued by the controller. An adjustable valve core and drive device are provided inside it, which can realize periodic changes in the valve core opening.

[0067] During the flushing process, the controller periodically adjusts the opening of the flow regulating valve 8, which can effectively enhance the flushing effect.

[0068] Specifically, when the flushing function is activated, the controller periodically adjusts the opening of flow control valve 8 according to preset regulation logic, increasing and decreasing the opening. This cyclical regulation causes the velocity and flow rate of water in the pipeline to continuously vary, generating a "pulse"-like impact force. This more effectively flushes residual foam from every corner of the pipe walls and fittings, particularly those prone to dead spots, such as inside valves and around pipe bends. Compared to traditional constant-flow flushing methods, this cyclical flow adjustment significantly improves the thoroughness and cleanliness of flushing, reduces the risk of corrosion and clogging caused by residual foam, extends the service life of the pipes and equipment, and enhances the overall performance and reliability of fire trucks.

[0069] This principle is based on the fluid mechanics principle of how flow changes affect flushing effectiveness. When the opening of flow control valve 8 increases, the water flow rate and velocity increase, the kinetic energy of the water flow increases, and the flushing force on the pipe wall is enhanced. When the opening decreases, the water velocity decreases, but the flow pattern of the water in the pipeline changes, potentially generating local eddies and turbulence, which helps flush dirt attached to the pipe wall. By periodically changing the opening of flow control valve 8, high-speed water impact and turbulent flushing effects are alternately generated, ensuring that every part of the pipeline is fully cleaned. The controller precisely controls the opening change period and amplitude of flow control valve 8 based on preset time intervals or feedback from the flushing process, achieving refined control of the flushing process and ensuring the optimal flushing effect within a limited flushing time.

[0070] The periodic adjustment method in this embodiment can be uniform speed change adjustment, variable speed change adjustment, or irregular change adjustment. It can achieve better flushing effect as long as the flow control valve 8 can be adjusted to different openings.

[0071] In a preferred embodiment, a second pressure sensor 17 is provided at the output end of the flushing power device, and a first pressure sensor 16 is provided at the water outlet of the water pump 3 ; the pressure value of the second pressure sensor 17 is smaller than the pressure value of the first pressure sensor 16 .

[0072] This embodiment adds pressure sensors to the previous one. Specifically, a second pressure sensor 17 is installed at the output of the flushing power unit to monitor the pressure in the flushing pipeline in real time. A first pressure sensor 16 is also installed at the outlet of the water pump 3 to detect the pressure of the water being pumped out. These two pressure sensors are connected to the controller via signal lines, transmitting pressure data to the controller in real time.

[0073] The setting of the first pressure sensor 16 and the second pressure sensor 17 can not only assist in judging the pressure status during the flushing process and ensure the safety and effectiveness of the flushing operation, but also control the pressure of the flushing pipeline by comparing the pressure values ​​of the second pressure sensor 17 and the first pressure sensor 16 when executing the flushing function to prevent the backflow of foam liquid.

[0074] When the pressure value of the second pressure sensor 17 is less than the pressure value of the first pressure sensor 16, it means that the pressure of the flushing pipeline is relatively low. At this time, the water flow can smoothly enter the foam pipeline for flushing, and at the same time avoid the foam liquid from flowing back into the water tank 1 or other equipment due to excessive pressure, thereby ensuring the smooth progress of the flushing process and the safe operation of the equipment, and improving the reliability and stability of the entire flushing system.

[0075] Based on the principle of pressure balance in fluid mechanics, the direction of water flow and pressure distribution are closely related in a piping system. When the pressure at the output of the flushing power unit (i.e., the pressure detected by the second pressure sensor 17) is lower than the pressure at the outlet of the water pump 3 (i.e., the pressure detected by the first pressure sensor 16), the water flow, under the action of the pressure differential, will preferentially flow from the higher-pressure outlet of the water pump 3 to the lower-pressure flushing pipeline, thereby entering the foam pipeline for flushing. At the same time, the pressure differential effectively prevents foam liquid from flowing back from the flushing pipeline into the water tank 1 or other high-pressure areas, protecting the purity of the water in the water tank 1 and the normal operation of the equipment. By monitoring the data from the two pressure sensors in real time, the controller dynamically adjusts the operating status of the flushing power unit, such as adjusting the speed of the electric flushing pump 4, to maintain the pressure in the flushing pipeline lower than the outlet pressure of the water pump 3, ensuring a safe, stable, and efficient flushing process.

[0076] In a preferred embodiment, when the conductivity detected at the input end of the drain valve 11 is the same as the conductivity detected in the water tank 1 , or the error is within a set range, the flushing power device is turned off.

[0077] In this embodiment, the first conductivity sensor 14 and the second conductivity sensor 15 can accurately determine the end of flushing, thereby avoiding over-flushing or under-flushing.

[0078] During the flushing process, first conductivity sensor 14 continuously monitors the conductivity of the liquid discharged from the drain, while second conductivity sensor 15 monitors the conductivity of the water in tank 1. A controller compares these two conductivity values ​​in real time. When the conductivity at the drain matches that of tank 1, or the error is within a set range, it indicates that the remaining foam in the pipeline has been flushed away. At this point, the controller issues a command to shut down the flushing power unit, halting the flushing operation. This conductivity-based judgment method objectively and accurately reflects the flushing effect, unaffected by human factors and ambient light conditions. It improves the reliability and consistency of flushing completion judgment, effectively conserves water resources and flushing time, reduces equipment wear, and improves the maintenance efficiency and cost-effectiveness of the fire truck foam system.

[0079] In a preferred embodiment, when the flushing power device is turned off, the drain valve 11 remains open, and after the second set time has passed, the controller closes the drain valve 11 .

[0080] The drain valve 11 is installed at the drain port of the pipeline and is used to control the discharge of liquid in the pipeline. It is connected to the controller and receives the valve opening and closing command signals issued by the controller. It is equipped with an electric or electromagnetic drive device inside, which can realize fast and accurate opening and closing actions.

[0081] After the flushing power device is turned off, the drain valve 11 is kept open for a period of time, such as 30 seconds, to ensure that the residual liquid in the pipeline can be fully drained. When the flushing process is completed and the controller turns off the flushing power device, if some flushing liquid still remains in the pipeline, the drain valve 11 will continue to remain open. After the second set time has passed, the controller will issue a command to close the drain valve 11.

[0082] This delayed closing method helps to further reduce the amount of residual liquid in the pipeline, and reduces corrosion, freezing and other problems that may be caused by liquid accumulation in the pipeline. It also helps to reduce the pressure of the pipeline system, prevent mechanical damage such as pipeline expansion and deformation caused by liquid residue, improve the reliability and service life of the pipeline system, and ensure that the foam system can operate normally when the fire truck is parked for a long time or restarted, without being affected by residual liquid from the previous flushing.

[0083] The beneficial effects of the embodiments of the present invention are: By detecting the flow switch 9, the flushing function is automatically awakened. After the set conditions are met, the flushing power device is started and the flushing process is executed, thereby realizing the automatic flushing function and avoiding corrosion damage to pipelines or pipeline equipment caused by foam accumulation due to firefighters' forgetfulness.

[0084] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An automatic foam flushing device, suitable for a fire truck foam system, comprising a water tank and a foam tank, characterized in that: It also includes a controller, a water outlet valve, a water pump, a drain valve, a foam induction valve, a venturi tube, a flow regulating valve, a flow switch, a foam outlet valve and a flushing power device; The water outlet valve is provided at the input end of the water pump and is used to control the communication state between the water pump and the water tank; The foam tank, the foam outlet valve, the flow switch and the flow regulating valve are connected in sequence, and the output end of the flow regulating valve is connected to the negative pressure suction end of the venturi tube; The water tank, the water outlet valve, the water pump and the drain valve are connected in sequence; The high-pressure water inlet of the venturi tube is connected to the output end of the foam induction valve, and the input end of the foam induction valve is connected between the water pump and the drain valve; The mixed liquid outlet of the venturi tube is connected between the water outlet valve and the water pump; The input end of the flushing power device is connected between the water tank and the water outlet valve, and the output end of the flushing power device is connected between the foam outlet valve and the flow switch; The controller is respectively connected to the water outlet valve, the water pump, the drain valve, the foam inducing valve, the flow regulating valve, the flow switch, the foam outlet valve and the flushing power device by signal.

2. The automatic foam flushing device according to claim 1, characterized in that: The input end of the drain valve is provided with a first conductivity sensor, and the water tank is provided with a second conductivity sensor.

3. The automatic foam flushing device according to claim 1, characterized in that: The flushing power device is an electric flushing pump.

4. The automatic foam flushing device according to claim 1, characterized in that: The output end of the flushing power device is provided with a flushing valve, and the output end of the flushing valve is connected between the foam outlet valve and the flow switch.

5. The automatic foam flushing device according to claim 4, characterized in that: A one-way valve is provided at the output end of the flushing valve, and the output end of the one-way valve is connected between the foam outlet valve and the flow switch.

6. A control method for the automatic foam flushing device according to any one of claims 1 to 5, characterized in that: The controller reads the signal of the flow switch in real time, and when the flow switch detects the flow signal, wakes up the flushing function and waits for flushing; When the flow rate of the flow switch is zero and lasts for a first set time, and the water outlet pressure of the water pump is less than a set value, the flushing function is executed.

7. The control method according to claim 6, characterized in that: When the flushing function is executed, the controller controls the opening of the flow regulating valve to perform periodic adjustment.

8. The control method according to claim 6, characterized in that: The output end of the flushing power device is provided with a second pressure sensor, and the water outlet of the water pump is provided with a first pressure sensor; The pressure value of the second pressure sensor is smaller than the pressure value of the first pressure sensor.

9. The control method according to claim 6, characterized in that: When the conductivity detected at the input end of the drain valve is the same as the conductivity detected in the water tank, or the error is within a set range, the flushing power device is turned off.

10. The control method according to claim 9, characterized in that: When the flushing power device is turned off, the drain valve remains open, and after a second set time, the controller closes the drain valve.

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