Technical guidance: Use the switch method to compare fire pump main equipment

Abstract: The main standby switch of fire pump is the necessary condition to ensure the operation of fire reserve pump. The key to its switching method is the choice of control signal. In this paper, comparing the two main methods of switching between fire pump and standby, this paper puts forward the method that the pressure signal control method is better than the current signal in the fire water supply system and the pressure signal control method is suggested. Key words: fire pump; fire standby pump; switching method; fire pump comparison is the heart of the water supply system. In the fire water system, the installation of fire reserve pump can increase the safety of the entire system, help to improve the reliability of the entire fire water system. According to the national standard "Code for fire protection of building design" (GBJ16-87), except for factories, warehouses and units of seven-storey to nine-storey residential outdoor fire fighting water not exceeding 25L / s, a fixed pump shall be provided for the standby fire pump , Its working capacity should not be less than one main pump. 7.5.3 of "Code for Fire Protection of High-Rise Civil Buildings Design" (GB50045-95) also stipulates that fire-fighting water supply system shall be equipped with spare fire-fighting water pump. The main standby switch fire pump standby fire pump to achieve an important means of investment, but also fire water supply system, reliable, safe operation of an important part. 1, the main standby switch fire pump from the fire pump start signal acquisition and control point of view, the design of the main standby switch fire pump There are two main ways. The key is to control the choice of signal source, which can be divided into current signal control method and pressure signal control method. Usually fire pump main and backup pumps are required to be mutually alternative way to design. Current signal control method is now the fire control design of fire pump standby switch the common method. It is through the pump motor current signal feedback to determine whether the fire pump is working. When the motor is short circuit (power off), the current is too large, the power automatically switches to another pump unit motor, stop the first fire pump, start another fire pump. Pressure signal control method is set in the fire pump water outlet manifold node pressure gauge, as shown in Figure 1, the main fire pump standby switch is judged by the pressure gauge signal. When the fire pump control box received an action command, immediately start any fire pump, fire pump if the work of the electricity gauge pressure gauge indicates the pressure fails to reach the set pressure value, the control box will automatically switch to another Fire pump, start working. Of course, the principle of electric fire pump control can be arbitrarily designated a fire pump as the main pump or spare pump. Current signal control method in the current domestic use of the earliest, most of the pressure signal control methods in foreign sprinkler system began to use, the pressure signal control method for automatic fire control system provides a reliable way. Abstract: The main standby switch of fire pump is the necessary condition to ensure the operation of fire reserve pump. The key to its switching method is the choice of control signal. In this paper, comparing the two main methods of switching between fire pump and standby, this paper puts forward the method that the pressure signal control method is better than the current signal in the fire water supply system and the pressure signal control method is suggested. Key words: fire pump; fire standby pump; switching method; fire pump comparison is the heart of the water supply system. In the fire water system, the installation of fire reserve pump can increase the safety of the entire system, help to improve the reliability of the entire fire water system. According to the national standard "Code for fire protection of building design" (GBJ16-87), except for factories, warehouses and units of seven-storey to nine-storey residential outdoor fire fighting water not exceeding 25L / s, a fixed pump shall be provided for the standby fire pump , Its working capacity should not be less than one main pump. 7.5.3 of "Code for Fire Protection of High-Rise Civil Buildings Design" (GB50045-95) also stipulates that fire-fighting water supply system shall be equipped with spare fire-fighting water pump. The main standby switch fire pump standby fire pump to achieve an important means of investment, but also fire water supply system, reliable, safe operation of an important part. 1, the main standby switch fire pump from the fire pump start signal acquisition and control point of view, the design of the main standby switch fire pump There are two main ways. The key is to control the choice of signal source, which can be divided into current signal control method and pressure signal control method. Usually fire pump main and backup pumps are required to be mutually alternative way to design. Current signal control method is now the fire control design of fire pump standby switch the common method. It is through the pump motor current signal feedback to determine whether the fire pump is working. When the motor is short circuit (power off), the current is too large, the power automatically switches to another pump unit motor, stop the first fire pump, start another fire pump. Pressure signal control method is set in the fire pump water outlet manifold node pressure gauge, as shown in Figure 1, the main fire pump standby switch is judged by the pressure gauge signal. When the fire pump control box received an action command, immediately start any fire pump, fire pump if the work of the electricity gauge pressure gauge indicates the pressure fails to reach the set pressure value, the control box will automatically switch to another Fire pump, start working. Of course, the principle of electric fire pump control can be arbitrarily designated a fire pump as the main pump or spare pump. Current signal control method in the current domestic use of the earliest, most of the pressure signal control methods in foreign sprinkler system began to use, the pressure signal control method for automatic fire control system provides a reliable way. 2.3 Comparison of Two Control Methods The current signal control method and the pressure signal control method are the main and standby switching modes of the fire pump. Fire pump control requirements are the same, and the two methods of signal acquisition is different, the ultimate control of the effect is also different. It is of great significance to choose the way of the main standby switch of the fire pump. It is an important guarantee for the reliability of fire water supply system. Pressure signal control method is conducive to the true control of BA, especially for automatic sprinkler system. 2.4, the pressure signal control method should pay attention to the problem In the design of the pressure signal control method, pay attention to the following questions to ensure the reliability of the main switch standby fire pump. (1) The electric pressure gauge should be located on the water main of the fire pump and should not be located in front of the fire pump valve (in the direction of water flow). The pressure setting should be greater than the water pressure of the high fire tank. This is because the pressure signal should be able to truly reflect the fire pump and system water supply operating conditions. If the pressure gauge is located in front of the fire pump outlet valve and the valve is closed by mistake, the fire pump may display normal water pressure while it is operating normally. However, the system's water supply condition is not normal. Therefore, the use of pressure signal control method of switching can also adjust the fire pump pipeline abnormal water conditions, and timely start another water pipeline fire pump. (2) in the signal control to determine the circuit design, to be switched to set a certain time delay. This is mainly due to the need to have a start-up time after the start of the fire pump and the passage of water within the pipeline, to determine the time delay greater than the above two factors, generally can be used 1 ~ 2min. In this way, the electric node pressure signal control value has the authenticity. (3) Switching of pressure signal control method The main pump or spare pump of the fire pump can be arbitrarily designated, and can also be switched periodically. (4) fire pump control in addition to automatic control, there should be local (manual) control functions. Fire pump work signals need to be sent to the fire control center for monitoring, control and building self-control records. In the design of fire power should consider enough fire pump capacity. In the fire pump switch, it is recommended not to stop the first fire pump power supply, that is, according to the most unfavorable when two fire pump power supply design, which is conducive to meet the fire water supply system in overload condition operating conditions, and Fire pumps can reduce the time interval at the switch, as soon as possible to put the fire pump into operation to improve the fire water supply time. 3 Conclusion (1) The main switch standby fire pump control signal selection. The main method of switching fire pump main and standby current signal control and pressure signal control. (2) In the fire water supply system, the integrated pump works, the use of pressure signal control method is better than the current signal control method. Pressure signal control method can truly reflect the fire fighting water supply conditions, the switching signal reliability. Proposed in the relevant fire code clear fire pump standby switch the pressure signal control method. (3) When using the pressure signal control method, the electrical signal pressure gauge switching signal should be set in the fire pump outlet manifold or after the hydraulic alarm valve. At the same time, the circuit design needs to set a certain delay and then to determine the value of pressure gauge pressure node.