Vacuum pumps commonly used in pharmaceutical equipment
In the pharmaceutical equipment industry, there is usually vacuum evaporation, vacuum concentration, vacuum conveying, vacuum sterilization, vacuum drying, vacuum packing and vacuum mixing emulsification and other vacuum equipment. Used by these devices must be equipped with a vacuum pump, vacuum pump with liquid ring vacuum pump, water injection pump and steam jet pump, the several kinds of vacuum pumps can be directly pumping water vapour and several common rotary vane pump, reciprocating pump, plunger pump, roots pump and so on, although they cannot pumping water directly, but can use if asked to be associated with condensation space and the surrounding environment clean, no pollution, also can be applied to all kinds of dry pump dry pump more responsibility at present, but it is the future development direction.
Introduction liquid ring vacuum pump for pharmaceutical industry.
1 working principle liquid-ring vacuum pump is a volume pump whose working medium is liquid. If the liquid is water, it is called water ring vacuum pump. Its working principle, as shown in the Yu 1 a eccentric impeller (rotor) installed in the column shell, when the impeller rotates, due to the effect of centrifugal force, make the water in the pump shell to jilt to form such as the thickness of ice water ring b ring and impeller tangent form crescent-shaped space d, this space cavity is divided into several small rooms, and gradual change along with the impeller rotation. When this space is small, it forms the suction chamber e pump suction gas when the space of the moon is formed by a large variable hour to form the exhaust cavity f pump to discharge the gas to achieve the pumping action of the pump.
2. The liquid ring pump can not be used to obtain the inlet pressure lower than the working liquid steam pressure. If the liquid vapor pressure is close to the inlet pressure, the cavitation will cause damage to the pump. Such as ice in 15 c when steam pressure is 103 pa, to avoid cavitation, allowing the minimum inlet pressure of water ring pump is 3.3 X103Pa. If need to inlet pressure is lower than the value l should be even more low vapour pressure of medium such as kerosene, styrene and ethylene glycol limit pressure of 6.7 X from the pump discharge side flow of gas and liquid mixture into the separator in the separator gas-liquid separation, not out of gas containing liquid with temperature of steam pressure, steam content. The operation mode of liquid ring pump is considered in terms of the price of working fluid and environmental protection. The main characteristics of the operation mode is the use of a large number of new liquid decreases, most of the liquid from the inner pump suction separator return pump before joining cold liquid, make the pump inlet temperature constant basically.
Liquid ring pump operation schematic diagram if liquid ring pump pumping toxic or harmful gases, or because of work need to work must use the high price of liquid, in can't vent shall be separated from the separator gas recycling, while the separated liquid cooling by heat exchanger to pump fluid after the normal operating temperature, all return to the pump.
The operating condition of the water ring type vacuum pump is that the air inlet gas pressure of the pump is 20CI, and the air inlet gas pressure of 70% is 101.325kPa pump working fluid is 15C water. The temperature of the working liquid and its vapor pressure seriously affect the pumping speed. The pressure of the working fluid in the extraction chamber and the impeller is increased with the increase of temperature, and the result is that the gas volume of the transport gas decreases and the pump speed decreases. Yu 3 shows are pumping gas is 20 c dry air, and water for pump working liquid, in the pumping speed of different temperature SU2, 15 c and pumping speed into a pressure p, single-stage pump working fluid temperature on the influence of the pumping speed is pumped gas on the pump performance may also be affected. If the exhaust gas is composed of air and steam mixture, then condensing can occur when the pumping steam is in contact with the cold working liquid, and the pumping speed increases. In the case of the working fluid of 15C water, the pumping speed of a certain amount of air and water vapor mixture at different temperatures (35.5 and 20C dry air) was extracted at a rate of 3 (35.5 and 20C). Of course, the ratio of air to water vapor has different effects on the pumping speed.
If conveying dry air, due to the heat capacity of small dry air, it the single-stage pump steam saturated gas temperature on the influence of the pumping speed was quickly cooled to working liquid temperature, the gas is pumped between the working liquid and the larger the volume of a gas decreases with temperature, the result can make the liquid ring pump pumping speed increase. If the pumped gas is dissolved in the working fluid it will be released as the working fluid enters the pump inlet side and the result will decrease the pumping speed. The required power of liquid ring vacuum pump is subject to the working fluid viscosity, density, flow and outlet pressure.