Classification and characteristics of the hottest

2022-08-18
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Classification and characteristics of vacuum pumps

vacuum pumps are widely used in metallurgy, chemical industry, food, electronic coating and other industries. According to the structure classification, they can be divided into mechanical vacuum pumps, jet vacuum pumps, and suction vacuum pumps

vacuum pumps are widely used in metallurgy, chemical industry, food, electronic coating and other industries. According to the structure classification, they can be divided into mechanical vacuum pumps, jet vacuum pumps, and suction vacuum pumps

there are many kinds of mechanical vacuum pumps, and they are gas conveying machines. Their dynamic performance and structural strength are similar to those of compressors

(I) reciprocating vacuum pump

reciprocating vacuum pump is the oldest structural form. It has solid structure, reliable operation and is insensitive to moisture. The limit 238 curtain wall and large window wall pressure is (1~2.6) kPa, and the pumping speed range is () l/s. It is mainly used in large crude vacuum systems, such as vacuum drying, vacuum filtration, vacuum concentration, vacuum distillation, vacuum crystallization and other gas extraction. Reciprocating vacuum pumps are not suitable for pumping out dusty or corrosive gases unless they have been specially treated

the reciprocating vacuum pump is composed of the working chamber composed of cylinder and piston and the transmission parts such as crankshaft, connecting rod, crosshead and piston rod. There are two kinds of valves to control the gas suction and discharge cylinder: automatic valve and forced valve

(II) oil sealed rotary vacuum pump

oil sealed rotary vacuum pump can be directly used as air extraction or as the front stage pump of other main pumps, and the limit pressure is 6 × PA, pumping speed 0 L/S。

oil seal rotary vacuum pump mainly has three structural types: rotary vane type, fixed vane type and slide valve type. Its characteristics are: use oil to separate the pump body from the exhaust system, which can prevent the exhaust gas from returning to the pump (so it is called oil seal type). Oil separation device must be set in the pump to separate and replace the lubricating oil taken away by fossil fuel based products during exhaust; Generally, it is still difficult to completely remove the oil vapor, so it will cause oil pollution to the vacuum system and the surrounding environment

(III) liquid ring vacuum pump

liquid ring vacuum pump is often used in oil refining and chemical production. It uses the periodic change of volume between liquid ring and blade when the impeller rotates to pump gas. Liquid ring vacuum pump is also known as Nessler pump. Because water is used as working liquid in most occasions, it is often called water ring vacuum pump after several years of research and development. The utility model has the advantages of simple structure and reliable operation. It can suck solid particles, water or flammable and explosive gases. According to the nature of the gas, it can also suck corrosive gases by using appropriate working liquid. When the water is working liquid, it will not pollute the environment and vacuum system. The limit pressure of single-stage longitudinal elastic recovery, permanent deformation and tension retention test is 104pa, the two-stage can reach 103pa, and the maximum pumping speed is 500L/s. Its disadvantages are large hydraulic loss and low efficiency. The hydraulic efficiency is about 50% - 70%

(IV) roots vacuum pump

roots vacuum pump, two 8-shaped rotors rotate in the same opposite direction, and the gas is brought from the inlet to the outlet. The pumping speed range of Roots vacuum pump is (30~3) × 104/s, the first stage limit pressure is about 1~10pa, and has a large stable pumping speed within the pressure range of 1~102pa, so it is also called fast vacuum pump; Roots vacuum pump is often used as the front pump of jet pump and oil diffusion pump to boost pressure, so it is also called mechanical booster pump

rotor blade clearance of Roots vacuum pump: the small is 0.1~0.2mm, and the large is 0.2~0.4mm, so it is not sensitive to dust, fiber, moisture, etc. in the gas, but it is not suitable to pump corrosive, flammable and explosive gases. There are no friction parts in the working chamber of roots pump, so there is no need for oil lubrication, and there will be no oil pollution

when the pressure ratio is high, its exhaust temperature may be very high, so it needs water for cooling, and the cooling water pipe is set at the exhaust port of the pump

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