Using the pressure signal control method, can truly reflect the actual work of the fire pump unit, the signal reliability of the switch is higher. Whether the motor fault or pump failure, as long as the fire pump outlet pipe pressure did not reach a certain pressure value, the time switching of main and standby fire pump. However, the pressure signal control method also has its disadvantages. When the actual water amount is larger when the fire water supply system, fire pump outlet pipe pressure drop after the switching signal malfunction caused by the fire pump pressure switch, stop a fire pump into a fire pump start. Pump in the switch, restart the need to have a certain time. In this way, it is bound to cause the fire water supply interruption, delay fire. In addition, the pressure signal control method can also be considered in the circuit design of the short circuit, overload, over-voltage, lack of phase, under pressure, overheating and other protective functions.
From the aspect of system analysis, the fire pump and motor as the fire pump, the water supply is to determine the final effect of pump unit whether water should be using main and standby switching method of pressure signal control is more reasonable. In the fire water supply system of water flow over the design, can be adjusted in the control circuit, the design of fire pump with expanding capacity, ensure all fire pump work of electricity consumption, electricity consumption and fire pump in fire period is just a part of all the fire power, the fire power supply system as for the influence. So, the outlet pressure is reduced, the other to start a fire pump in a timely manner, may not have to consider closing the original fire pump.
From the point of view of reliability, the reliability of the water supply system of the fire pump is related to the reliability of the structure. The reliability block diagram of the set of the fire pump set can be expressed as the series connection between the pump and the motor, the parallel relationship between the unit and the unit.
It is worth noting that, in the setting of fire pump outlet pressure, water pressure should be considered the high water tank fire extinguishing early. Therefore, for the temporary high pressure fire water supply system, the set pressure value should be greater than the normal water supply pressure of the pipe network. Another after the fire main pump, the need to set a certain delay, to determine the pressure value of the node pressure gauge, determine whether the need to switch to another fire standby pump. And suggestions will be set in the fire pump outlet pipe valve electrical node pressure gauge (by flow direction) of the fire water mains, the sprinkler system and hydraulic valve should be set back in the fire pump outlet pipe check alarm valve, to ensure the reliability of pressure signal.
