Like the fire pump, the diesel engine driven fire water pump is mainly used to extinguish the fire. It is used to ensure the water quantity and pressure of the fire water. It involves personal safety and property protection, and must be operated more reliably. The pump body structure is more reasonable, the material is more appropriate, and the reliability is higher. The requirements are quick and timely, the corresponding requirements are that the pumping time of the fire pump is shorter than that of the ordinary life pump, and the starting performance is better.
Fire pumps Before calculating the over-flow size of fire pumps, the pump speed must be selected and determined. In general, when selecting and determining the speed of the turbine feed water pump, the following serious factors can be expressed: the economic speed of the turbine.
If the pump is designed based on a similar algorithm, after obtaining the speed n required for the operating conditions, you can convert the single arc under the corresponding operating conditions according to the formula, that is, you can get the speed and multi-levels of six working conditions. The characteristic curve of starting and ending working conditions of fire pump is the first step of water pump design. Under all working conditions, to make the feed water pump run smoothly and reliably, the most serious case is to ensure that no cavitation phenomenon occurs under each working condition, and no guarantee conditions should be placed in advance without cavitation. Pump booster pump supply. Design and calculation of pre-filled fire pump The pre-boost pump is called booster pump, which is placed once in the suction port of the boiler feed pump and provides enough water supply pump to not show the suction pressure required for cavitation under operating conditions. Before designing and calculating the booster pump, a single-stage fire pump is first required to determine its design calculation flow rate and head value. Due to the connection between the booster pump and the feed water pump, the design parameters of the booster pump have been accurately determined and related to the corresponding operating parameters of the feed water pump.
The impeller is installed in the pump body. When the impeller rotates without error, the water that the pump body enters the pump body is thrown to the limit by the impeller. Due to the centrifugal force, the thickness of the water is similar to the shape of the pump cavity. Closed water ring. The upper inner and outer surfaces of the water ring are exactly tangent to the impeller hub, while the lower inner surface of the water ring is exactly opposite to the top of the blade (in fact, the blade has a certain insertion depth in the water ring). At this time, a crescent-shaped space is formed between the center of the impeller and the water ring. This space is divided into several small chambers by the impeller, in which there are a large number of blades. If the upper impeller at the beginning is 0 °, when the fire pump impeller rotates 180 °, the volume of the chamber gradually increases from small to large, and the pressure keeps decreasing, with the suction inlet and exhaust plate. When the pressure in the cell space is lower than the pressure in the pumping container, according to the principle of balancing the gas pressure, the pumping air is continuously pumped into the cell and during the inhalation process.
When suction is completed, it separates from the suction port. The volume of the small cavity gradually decreases and the pressure continues to increase. At this time, the process is in a shrinking process. When the compressed gas reaches the exhaust pressure early, the exhaust valve is assisted. exhaust. The volume of the chamber communicating with the exhaust port further reduces the pressure for further promotion. When the gas pressure remains stable against the exhaust pressure, the compressed gas is discharged from the exhaust port during the continuous operation of the pump. Continuously perform suction, compression, and exhaust processes.