In the multi-stage injection pump system, the gas mixture excluded by the forepump contains water vapor that can not work. To reduce the gas load of the subordinate pump, an intermediate condenser is provided. The condenser can condense the water vapor in the mixed gas into water and form Condenser return pipe into the backwater pool, to save the job steam consumption purposes. The essence of the use of the condenser is to increase the consumption of condensate water in exchange for the amount of working steam savings to low-priced water in exchange for high-priced steam, so that pump operating costs are reduced. The setting of the condenser is not only related to the temperature of the condensed water but also to the partial pressure of the water vapor in the pump to remove the gas. When the partial pressure of the water vapor in the mixed gas is higher than the saturated pressure corresponding to the temperature of the water into the condenser, a condenser , In order to reduce the consumption of working steam of the subordinate pump. In a steam jet pump with an intermediate condenser, the exhaust pressure that can be established for the previous stage of pumping of the exhaust gas into the condenser depends essentially on the temperature of the water in the intermediate condenser, The outlet pressure can not be lower than the saturated steam pressure of the condensate in the subsequent condenser. When the condensate water temperature is 25 ~ 30 ℃, this level of the outlet pressure of about 4000Pa, in fact there is air resistance of the condenser (usually 670 ~ 1330Pa), so this stage pump outlet pressure is higher than 4000Pa, if this Level compression ratio of 5 to 10, then this level of inlet pressure can not be low 400 ~ 800Pa, if the first stage pump inlet pressure 50 ~ 80Pa, the first stage compression ratio can not be less than 8 to 10. Condenser according to the structure: hybrid condenser, surface condenser, jet condenser, which is due to its simple structure, high efficiency heat exchanger in the jet pump is widely used. According to its installation position, the condenser can be divided into front condenser, intermediate condenser and rear condenser. Among them, the intermediate condenser is the most widely used. In the multi-stage injection pump system, it is often necessary to set several intermediate condensers.
