Steam jet pump working principle and suction system characteristics

[Asia Pump Network News] jet pump is a fluid pump. Fluid power pumps do not have mechanical transmission and mechanical working components, it uses another working fluid energy as a power source to deliver low-energy liquid, used to pump flammable materials with good safety. Xiaobian now to introduce the steam jet pump working principle and suction system characteristics. Steam jet pump First, the steam jet pump works Steam jet pump is the use of high-pressure steam after the nozzle acceleration, access to the supersonic flow, into the mixing chamber, causing low pressure in the mixing chamber, will be pumping gas (or steam) inhalation, and with The momentum and energy exchange, into the diffuser. In the diffuser contraction section, the pressure of the mixed gas increases and the velocity decreases, reaching the throat of the diffuser, the velocity of the mixed gas stream drops to the vicinity of the sound velocity. In the diffuser expansion section, the velocity is further reduced to a velocity close to Zero, at this time, the pressure of the mixed gas is higher than the outlet pressure of the pump is excluded, so as to achieve the purpose of pumping. After the working steam is expanded by the nozzle, if the pressure at the outlet of the working steam is much higher than the pressure of the gas being pumped, the working steam will disperse the jet due to over-expansion, and at this time, there is no air-pumping effect. If the pressure at the outlet is much lower than the pressure of the evacuated gas, the working steam will be compressed and a columnar jet will be formed in the nozzle to block the air flow channel, resulting in a "short circuit" between the evacuation chamber and the suction chamber, Pumping effect. Second, the suction system features Multi-stage jet pump in all pump has its own suction characteristic curve, at all levels of pump work along their respective suction pressure, exhaust pressure and exhaust volume characteristic curve changes, in order to ensure that all levels The stable operation of the pump requires that during the working process of the system, the parameters of the steam system and the parameters of the condensate system of the pump are kept as constant as possible. When the status parameters of the working medium fluctuate within the allowable range, the suction pressure and the exhaust of each stage of the pump Pressure will be within the appropriate range of changes will not affect the normal operation of the jet pump system, but the status of the working media changes in the General Assembly caused by jet pump instability. In order to ensure the stable operation of multi-stage pump system, all the pumps in the system should be well matched, so that each level of pump is at its own working point, so as to prevent one of the pumps from operating under overload condition. As the gas load increases, the suction pressure of the jet pump increases significantly (about 1.6 times) and the exhaust pressure rises slightly (about 2%). If the gas load decreases, the suction pressure of the jet pump drops and the outlet pressure also drops. When the pump suction pressure is constant, if the working steam pressure increases, the exhaust pressure increases, the amount of exhaust increases. The cooling water temperature will generally vary with the seasons, the pump design is generally based on the summer water temperature. If the water temperature is low, the performance of the pump at all levels before the condenser will not be affected. The pump behind the condenser will reduce the gas load of the next-stage pump due to the low condensation temperature. becoming steady. However, in order to make the discharge pressure of the last stage pump> 10-5Pa, it may be uneconomical to increase the working steam consumption of the last stage of the pump, which may cause the pump system to fail to work stably when the working steam is constant. Further Reading: pump valve pipe fittings Exhibition 2016 Exhibition of Information Industry, Internet (Xiamen) Technology Co., Ltd. Author: Asian pumps Network Editor: Yao Xiaoxia (QQ / micro letter: 2355962924) http://beng.liuti.cn/ (Hotline : 400-6030-811)