2018年9月4日星期二
Classification Of Dry Vacuum Pumps
Dry vacuum pump is a kind of mechanical vacuum pump which can start pumping under atmospheric pressure, and can directly discharge the pumped gas into the atmosphere. There is no oil or other working medium in the pump cavity, and the pump’s limit pressure is equal to or close to that of oil-sealed vacuum pump.
Main types of dry vacuum pumps are classified as follows:
1. Dry screw vacuum pump
2, oil-free reciprocating vacuum pump
3. Claw vacuum pump
4, oil-free scroll vacuum pump
The working principle of dry vacuum pump:
1. Dry screw vacuum pump
Dry-type screw vacuum pump is a suction and exhaust device which uses a pair of screw rods to rotate in the pump shell at high speed and reverse synchronously. The two screw rods are supported by bearing and installed in the pump shell after fine dynamic balance correction. There is a certain gap between the screw and the pump shell. Therefore, when the pump works, there is no wear between the screw and the screw. Wipe, smooth operation, low noise, working chamber without lubricating oil, therefore, dry screw pump can be pumped containing a large amount of steam and a small amount of dust in the gas occasion, higher limit vacuum, lower power consumption, energy saving, maintenance-free and so on. It is an upgrading product of oil seal / water ring / jet vacuum pump.
2. oil-free reciprocating vacuum pump
Vacuum pump, also called piston vacuum pump, relies on the reciprocating motion of the piston to periodically change the working volume of the pump cavity (cylinder). The structure of reciprocating vacuum pump is similar to reciprocating piston compressor. When working, the suction pipe is vacuumed and the exhaust pipe passes through the atmosphere. Reciprocating vacuum pump can be used in vacuum distillation, vacuum concentration, vacuum crystallization, vacuum filtration, vacuum drying and concrete vacuum operation.
3. Claw vacuum pump
Claw vacuum pump is composed of multi-stage rotor, each stage has two rotors, two rotors rotate in the opposite direction, suction port and pump cavity connected, pump cavity volume becomes larger and suction, when the rotor closed suction port suction end, after the pump cavity becomes smaller and compressed gas, when the exhaust opening after the pump cavity exhaust, exhaust port closed, then Exhaust is finished, so circulate.
4. oil-free scroll vacuum pump
The scroll disc of a scroll oil-free vacuum pump is a scroll disc structure formed by one or more involute spirals connecting one end with a plane. A pair of scroll disks composed of a static scroll disk and a moving scroll disk constitute the basic pumping mechanism of a scroll oil-free vacuum. For example, in a two-stage scroll oil-free vacuum pump, there are two directions corresponding to the fixed scroll disk, a rotating scroll disk located between the two scroll disks. The relative motion of the dynamic and static vortex disks forms a crescent-shaped vacuum chamber with constant volume change, which makes the gas be sucked in and discharged from the exhaust port, and completes the exhaust cycle.
2018年9月3日星期一
CONTROL ANALYSIS OF OIL RETURN RATE OF OIL DIFFUSION PUMP
With the continuous development of vacuum technology, vacuum equipment has been widely applied in metallurgical industry. As the main pump of most high vacuum systems, oil diffusion pump has many advantages, such as simple structure, high pumping rate, easy to obtain high vacuum and so on. However, it is difficult to solve effectively in production practice for many years. In this paper, how to control the oil return rate of oil diffusion pump in order to obtain high vacuum system is discussed from the design principle of oil diffusion pump and the experience accumulated in production practice.
THE STRUCTURE AND WORKING PRINCIPLE OF OIL DIFFUSION PUMP:
The oil diffusion pump carries the gas through the oil vapor jet to achieve the goal of vacuum pumping. Oil diffusion pump structure. It is mainly composed of pump body, draft tube, fractionating ring and heater. Oil as working fluid in the oil pan below, heated by heater into oil vapor, rises along the diversion pipe, when oil vapor to the first, second and third-class nozzle, due to the sudden reduction of the cross-section of the nozzle, the speed of steam flow increases, high-speed oil vapor flow from the nozzle ejected, forming an umbrella, as long as the gas molecules touch Oil vapor is easily carried away, and then reaches the inner wall of the pump, the pump wall is cooled by cooling water, so oil vapor is condensed into oil droplets, along the pump wall into the oil pan, gas molecules can not be condensed out; oil is heated, evaporated into oil vapor, the first level of the gas molecules from the A1 zone to A2 zone A3 It is then sent to the exhaust port and pumped by the front stage pump to achieve exhaust.
THE STRUCTURE AND WORKING PRINCIPLE OF OIL DIFFUSION PUMP:
The oil diffusion pump carries the gas through the oil vapor jet to achieve the goal of vacuum pumping. Oil diffusion pump structure. It is mainly composed of pump body, draft tube, fractionating ring and heater. Oil as working fluid in the oil pan below, heated by heater into oil vapor, rises along the diversion pipe, when oil vapor to the first, second and third-class nozzle, due to the sudden reduction of the cross-section of the nozzle, the speed of steam flow increases, high-speed oil vapor flow from the nozzle ejected, forming an umbrella, as long as the gas molecules touch Oil vapor is easily carried away, and then reaches the inner wall of the pump, the pump wall is cooled by cooling water, so oil vapor is condensed into oil droplets, along the pump wall into the oil pan, gas molecules can not be condensed out; oil is heated, evaporated into oil vapor, the first level of the gas molecules from the A1 zone to A2 zone A3 It is then sent to the exhaust port and pumped by the front stage pump to achieve exhaust.
Main Parameters Of Vacuum Pump
Vacuum pump is a kind of rotary variable capacity, vacuum pump must have a front-stage pump with a wide range of pressure can be used to have a greater pumping speed, the extracted gas contains dust and water vapor insensitive widely used in metallurgy, chemical industry, food, electronic coating and other industries.
Vacuum pumps include liquid ring vacuum pump, reciprocating pumps, piston vacuum pump, rotary vane pumps, Roots pumps and diffusion pumps, etc. At present, these pumps are indispensable in the application of vacuum technology in various industries of our national economy. In recent years, with the sustained and high-speed development of China’s economy, vacuum pump related downstream application industry maintained a rapid growth momentum. At the same time, the vacuum pump industry in China has achieved sustained and stable development under the joint pull of factors such as expanding the field of vacuum pump application.
Vacuum pumps include liquid ring vacuum pump, reciprocating pumps, piston vacuum pump, rotary vane pumps, Roots pumps and diffusion pumps, etc. At present, these pumps are indispensable in the application of vacuum technology in various industries of our national economy. In recent years, with the sustained and high-speed development of China’s economy, vacuum pump related downstream application industry maintained a rapid growth momentum. At the same time, the vacuum pump industry in China has achieved sustained and stable development under the joint pull of factors such as expanding the field of vacuum pump application.
Oil Diffusion Vacuum Pump For High Vacuum Pump
Oil diffusion pump (abbreviated as oil diffusion pump) is a momentum transfer vacuum pump with low pressure and high speed oil vapor as working medium. The pump works in high vacuum area. The oil diffusion pump has the advantages of simple structure, convenient operation and low cost per unit pumping speed. The oil diffusion pump has no mechanical moving parts, long service life, high reliability and convenient maintenance. The oil diffusion pump is especially suitable for the process that requires rapid evacuation of large working vessels and rapid removal of large amounts of gases from treated materials during treatment. For example, vacuum metallurgy and vacuum heat treatment equipment.
When working, the oil diffusion pump and the system are pumped into a preparatory vacuum by the front-stage pump, and the boiler at the lower part of the pump is equipped with pump oil, which is heated by an electric heater to make it boil and evaporate to produce oil vapor. Due to pre-vacuum in the pump, the pressure is low, so the pump oil can be evaporated at a lower temperature (related to the type of working media, generally 370-420K). The diffusion pump oil evaporates rapidly into vapor in vacuum, and the vapor rises along the diversion pipe and is ejected from the umbrella nozzles at all levels. Umbrella shaped nozzles can be set at level 1, two, three and four. The oil vapor from the high-speed jet strikes the water wall and condenses into a liquid to flow back to the bottom of the pump. It is reheated and gasified, thus circulating continuously. The gas molecules in the pumped system diffuse into the vapor jet through the inlet and are carried to the next stage by the collision of a large number of high-speed directional oil molecules. The gas molecules are carried and compressed by the step-by-step diffusion, and are pumped out by the front stage pump through the outlet nozzle and the exhaust port.
When working, the oil diffusion pump and the system are pumped into a preparatory vacuum by the front-stage pump, and the boiler at the lower part of the pump is equipped with pump oil, which is heated by an electric heater to make it boil and evaporate to produce oil vapor. Due to pre-vacuum in the pump, the pressure is low, so the pump oil can be evaporated at a lower temperature (related to the type of working media, generally 370-420K). The diffusion pump oil evaporates rapidly into vapor in vacuum, and the vapor rises along the diversion pipe and is ejected from the umbrella nozzles at all levels. Umbrella shaped nozzles can be set at level 1, two, three and four. The oil vapor from the high-speed jet strikes the water wall and condenses into a liquid to flow back to the bottom of the pump. It is reheated and gasified, thus circulating continuously. The gas molecules in the pumped system diffuse into the vapor jet through the inlet and are carried to the next stage by the collision of a large number of high-speed directional oil molecules. The gas molecules are carried and compressed by the step-by-step diffusion, and are pumped out by the front stage pump through the outlet nozzle and the exhaust port.
2018年9月2日星期日
OIL CHANGING KNOWLEDGE OF WATER RING VACUUM PUMP
THE USE OF WATER RING VACUUM PUMP OIL:
Vacuum pump oil has the same function as ordinary lubricating oil, but the water content of vacuum pump is lower than that of ordinary lubricating oil, because the water evaporates back at high vacuum and occupies the pump displacement and the performance of vacuum pump decreases.
THE MAIN FUNCTION OF WATER RING VACUUM PUMP OIL :
In the process of using thermal conductive oil pump, because the vacuum pump oil directly into the pump chamber, when the vacuum pump runs, with the gas pressure gradually reduced, the pump temperature gradually increased. Molecular components with high saturated vapor pressure in oil products can evaporate into the vacuum space, which affects the reaching of the vacuum pump limit pressure, and can diffuse back to the vacuum system, causing pollution.
Vacuum Degree Of Rotary Vane Vacuum Pump
Rotary vane vacuum pump can set the upper and lower limits of the required vacuum, when the pump reaches the upper limit of vacuum operation will automatically stop, when the vacuum drops to the lower limit when the pump automatically starts. The oil level of rotary vane vacuum pump needs regular inspection. To check the oil level of the rotary vane vacuum pump, the oil level should be in the center of the oil mark of the rotary vane vacuum pump, the oil level is too low, the exhaust valve can not be sealed, affecting the vacuum degree; the oil level is too high, will cause the start of fuel injection.
Before the rotary vane vacuum pump runs, take off the triangle belt, turn the motor to correct, and then start to avoid injection. During operation, the oil level rises slightly, which is a normal phenomenon. When the fuel is insufficient, vacuum pump oil is added from the fuel hole. Oil needs to be filtered to prevent debris from entering and plugging oil holes.
Before the rotary vane vacuum pump runs, take off the triangle belt, turn the motor to correct, and then start to avoid injection. During operation, the oil level rises slightly, which is a normal phenomenon. When the fuel is insufficient, vacuum pump oil is added from the fuel hole. Oil needs to be filtered to prevent debris from entering and plugging oil holes.
Liquid Ring Vacuum Pump Is Applied In The Vacuum Coating Industry
Vacuum coating technology is an important branch of 2BV liquid ring vacuum pump application technology. It has been widely used in optics, electronics, energy development, physical and chemical instruments, construction machinery, packaging, civil products, appearance science and scientific research. The main methods of vacuum coating are evaporation plating, sputtering plating, ion plating, beam stacking plating and molecular beam epitaxy. Chemical vapor deposition is also used.
If the purpose of vacuum coating is to modify the physical and chemical properties of the animal surface, this technology is also an important part of the vacuum surface treatment technology. Now we will give a brief introduction to several main applications. First, in optics, a piece of optical glass or quartz coated with a layer or several layers of different substances on the surface of the film, can become a high reflection or no reflection (i.e. anti-reflective film) or make any expected proportion of reflection or transmission data, can also be used as an absorption of a certain wavelength, and the transmission of another wavelength filter.
High reflective coatings are needed from the start of large-aperture astronomical telescopes and lasers to coated jasmines for large windows in new buildings. Antireflective coatings are widely used in photography and in the beginning of various lasers, as well as in coated glass for large windows of new buildings. Antireflection coatings are widely used in cameras and television cameras. Vacuum coatings play an important role in electronics. A range of inheritance circuits. Including the memory, the arithmetic unit, the notification logic element and so on all need to use the conductive film, the insulation film and the maintenance membrane. Chromium films are used as mask for making circuits.
If the purpose of vacuum coating is to modify the physical and chemical properties of the animal surface, this technology is also an important part of the vacuum surface treatment technology. Now we will give a brief introduction to several main applications. First, in optics, a piece of optical glass or quartz coated with a layer or several layers of different substances on the surface of the film, can become a high reflection or no reflection (i.e. anti-reflective film) or make any expected proportion of reflection or transmission data, can also be used as an absorption of a certain wavelength, and the transmission of another wavelength filter.
High reflective coatings are needed from the start of large-aperture astronomical telescopes and lasers to coated jasmines for large windows in new buildings. Antireflective coatings are widely used in photography and in the beginning of various lasers, as well as in coated glass for large windows of new buildings. Antireflection coatings are widely used in cameras and television cameras. Vacuum coatings play an important role in electronics. A range of inheritance circuits. Including the memory, the arithmetic unit, the notification logic element and so on all need to use the conductive film, the insulation film and the maintenance membrane. Chromium films are used as mask for making circuits.
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