Vacuum pump is a device that produces, improves and maintains vacuum in a certain enclosed space by various methods. Vacuum pump can be defined as a device or equipment that uses mechanical, physical, chemical or physical chemical methods to pump the container to obtain vacuum. With the development of vacuum application, there have been many kinds of vacuum pumps, whose pumping speed has increased from a few liters per second to a few 100,000 liters per second, millions of liters per second. According to the working principle of vacuum pump, vacuum pump can be basically divided into two types, namely gas transmission pump and gas capture pump. As the requirements of vacuum application technology in the field of production and scientific research for its application pressure range become wider and wider, most of them need to be made up of several kinds of vacuum pumps. The vacuum pumping system can only meet the requirements of the process of production and scientific research after co-pumping. Because the scope of working pressure involved in the vacuum application department is very wide, therefore, any type of vacuum pump can not be completely applicable to all the working pressure ranges, and different types of vacuum pumps can only be used according to different working pressure ranges and different working requirements. For the convenience of use and the need of various vacuum process, sometimes various vacuum pumps are combined according to their performance requirements and applied in the unit type.
Working Principle of various vacuum pumps
Water Ring Vacuum pump/liquid ring vacuum pump working principle
Water Ring Vacuum Pump (water ring pump for short) is a kind of crude vacuum pump, and the ultimate vacuum it can obtain is 2000 ~ 4000 Pa, series atmospheric injectors can reach 270 ~ 670Pa. Water ring pump can also be used as compressor, called water ring compressor, which belongs to low pressure compressor, and its pressure range is 1 ~ 2 × 105 PA table pressure.
Water ring pump was initially used as self-priming pump, and then gradually used in many industrial sectors such as petroleum, chemical industry, machinery, mining, light industry, medicine and food, etc. In many technological processes of industrial production, such as vacuum filtration, vacuum water diversion, vacuum feeding, vacuum evaporation, vacuum concentration, vacuum recirculation and vacuum degassing, water ring pumps are widely used. Due to the rapid development of vacuum application technology, the water ring pump has always been paid attention to by people in the aspect of obtaining crude vacuum. Because the gas compression in the water ring pump is isotherm, flammable and explosive gas can be extracted, and in addition, the gas containing dust and water can be extracted. Therefore, the application of water ring pump is increasing day by day.
Install appropriate amount of water in the pump body as working fluid. When the impeller rotates clockwise according to the figure, the water is thrown around by the impeller. Due to the centrifugal force, the water forms a closed ring which is similar to the same thickness determined by the shape of the pump cavity. The inner surface of the lower part of the water ring is just tangential to the wheel hub of the impeller, and the inner surface of the upper part of the water ring is just in contact with 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 wheel hub of the impeller and the water ring, and this space is divided into several small cavities equal to the number of blades by the impeller. If the starting point is 0 ° of the lower part of the impeller, the volume of the small cavity will change from small to large when the impeller rotates 180 °, and it is connected with the suction port on the end face. At this time, the gas is inhaled, when the suction ends, the small cavity will be isolated from the suction port; when the impeller continues to rotate, the small cavity will become smaller and smaller, making the gas compressed; when the small cavity is connected with the vent, gas is discharged out of the pump.
In conclusion, the water ring pump relies on the change of pump cavity volume to realize the suction, compression and exhaust, so it belongs to variable volume vacuum pump.
Working Principle of Roots pump
Roots pump in the pump cavity, there are two "8" shape rotors vertical to each other on a pair of parallel shaft, by the transmission ratio of 1 a pair of gear belt action opposite to each other synchronous rotation movement. There is a certain gap between the rotor and the inner wall of the pump shell, which can realize high speed operation. Since the Roots pump is a kind of vacuum pump without internal compression, the compression ratio is usually very low, so the high and medium vacuum pumps need the front stage pumps. The ultimate vacuum of Roots pump not only depends on the structure and manufacturing precision of the pump itself, but also depends on the ultimate vacuum of the front stage pump. In order to improve the ultimate vacuum degree of the pump, Roots pump can be used in series.
The working principle of Roots pump is similar to that of Roots blower. Due to the continuous rotation of the rotor, the extracted gas is inhaled into the space v0 between the rotor and the pump shell from the air inlet, and then discharged through the air outlet. Since the space of v0 is totally closed after inhaling, the gas in the pump cavity is not compressed or inflated.
However, when the top of the rotor turns through the edge of the exhaust port and the v0 space is connected with the exhaust side, because the gas pressure of the exhaust side is relatively high, a part of the gas rushes back to the space V0, make the gas pressure increase suddenly. When the rotor continues to rotate, the gas is discharged out of the pump.
Working Principle of rotary disc vacuum pump
Disc vacuum pump (disc pump for short) is a kind of oil sealed mechanical vacuum pump. The working pressure range is 101325 ~ 1.33 ×10-2 (Pa) is a low vacuum pump. It can be used alone, and can also be used as the front stage pump of other high vacuum pumps or super high vacuum pumps. It has been widely used in metallurgy, machinery, military industry, electronics, chemical industry, light industry, petroleum, medicine and other production and scientific research departments.
The disc pump can pump out the dry gas in the sealed container, and if there is attached a gas stopping device, a certain amount of condensable gas can also be extracted. But it is not suitable for extracting gas that contains too high oxygen, corrosive to metal, chemical reaction to pump oil and particles and dust.
Vane pump is one of the most basic vacuum acquisition equipments in vacuum technology. Disc pumps are mostly small and medium-sized pumps. There are two kinds of Vane pumps: single-stage and double-stage. The so-called double-stage is to connect two single-stage pumps in series in structure. Generally, it is usually made into two-stage to obtain higher vacuum degree.
The relationship between the pumping speed of the disc pump and the inlet pressure is stipulated as follows: Under the inlet pressure of 562 Pa, 1.33Pa and 1.33 ×10-1 (Pa, the pumping speed value shall not be lower than 95%, 50% and 20% of the nominal pumping speed of the pump respectively.
Disc Pump mainly consists of pump body, rotor, rotor, end cover, spring, etc. Install a rotor in the cavity of the rotor pump eccentrically, the outer circle of the rotor is tangential to the surface of the pump cavity (there is a small gap between them), and two rotations with springs are installed in the rotor groove. When rotating, the top of the rotor keeps in touch with the inner wall of the pump cavity by centrifugal force and spring tension, and the rotor rotates to drive the rotor to slide along the inner wall of the pump cavity.
The two rotations divide the crescent-shaped space enclosed by the rotor, the pump cavity and the two end caps into three parts A, B and C. When the rotor rotates in the direction of Arrow, the volume of space A, which is connected with the suction port, is gradually increasing and is in the process of suction. However, the volume of space C which is connected with the vent is gradually shrinking, and it is in the process of exhaust. The volume of space B in the center is also gradually decreasing, which is in the process of compression. Because the volume of space A is gradually increasing (namely expansion), the gas pressure decreases, and the external gas pressure at the entrance of the pump is larger than that in space A, the gas is inhaled in. When space A is isolated from the suction port, it turns to the position of space B, the gas begins to be compressed, the volume gradually shrinks, and finally connects with the vent. When the compressed gas exceeds the exhaust pressure, the exhaust valve will be pushed away by the compressed gas, and the gas will flow into the atmosphere through the oil layer in the oil tank. The purpose of continuous pumping is achieved by the continuous operation of the pump. If the discharged gas flows into another level (low vacuum level) through the air passage, it is drained from the low vacuum level, and then discharged into the atmosphere after being compressed by the low vacuum level, then a two-stage pump is formed. At this time, the total compression ratio is undertaken by two levels, so the ultimate vacuum degree is increased.
Order instructions of Vacuum pump:
I. ① name and model of Vacuum pump product ② air inlet caliber of Vacuum pump ③ rotation speed of Vacuum pump (r/min) ④ extreme vacuum of Vacuum pump ⑤ motor power of Vacuum pump (KW) ⑥ oil consumption of Vacuum pump (L) ⑦ vacuum pump voltage (V) ⑧ vacuum pump cooling water volume (L/min) ⑨ whether the vacuum pump has accessories so that we can choose the right type for you.
