A vacuum pump, a device, the principle of which will be described below, is an equipment that is used to pump and remove vapors or gases to a given pressure level. The latter is also called a plumbing vacuum.
The development of vacuum technology starts in 1643. Then the atmospheric pressure was first measured. In the second half of the XIX century, mankind entered the technological stage of creating vacuum equipment and devices. This was due to the emergence of a mercury-piston pump, which happened in 1862.
Principle of operation
The principle of operation of the vacuum pump is that pumping is provided by changing the volume of the working chamber. Such positive displacement pumps are used to obtain preliminary discharge, which is called the forevacuum. These include pumps:
- rotational;
- liquid ring;
- piston.
The most popular in vacuum technology were rotary pumps. If we are talking about high-vacuum pumps, then they should include turbomolecular, steam-jet and steam-oil pumps. Molecular ones pump out due to the transfer of gas molecules from a solid, vaporous or liquid surface, the last of which moves at high speed.
These include ejector, water-jet, diffusion, molecular devices with the same direction of motion of surfaces and gas molecules. Turbomolecular aggregates, in which the motion of the solid surfaces of the injected gas occurs mutually perpendicularly, can also be attributed to the same class.
In addition about features of work
If you are interested in the principle of operation of a vacuum pump, then you should familiarize yourself with this topic in more detail. This process is not as easy as it might seem at first glance. It should start with the fact that the analysis of the internal structure of such vacuum generating units indicates that almost all devices of this type operate on the principle of displacement, which can be compared with the principle of operation of volumetric pumps. They are used for pumping decay products of various mixtures and water.
The created vacuum, or rather its magnitude, depends on the tightness of the space, which arises as a result of the operation of the pump mechanisms, among them it should be distinguished:
- wheels
- special plates;
- spools.
The principle of operation of the vacuum pump is that the unit must fulfill two conditions, the first of which is expressed in lowering the pressure in a confined space, while the second is to fulfill the previous condition for a certain period of time. It is important that the sequence of conditions is maintained.
When the gas medium is absorbed by the equipment, and the pressure is not reduced to the desired value, then the use of a fore-vacuum apparatus is required. This, in turn, will reduce the pressure of the gaseous medium. This principle implies the possibility of sequential connection of pumps.
The principle of operation of the vacuum pump should involve the use of vacuum oil, which eliminates gas leaks through the gaps of the rubbing parts. Thanks to the use of oil, it is possible to seal and completely close the gaps. This oil acts as an excellent lubricant.
Roots pump device
The principle of operation of a rotary vacuum pump was described above, but you can find information about its device in this section. The mentioned pumps can be classified as displacing rotary vacuum pumps that operate on dry run. Among the main components of the equipment should be highlighted:
- engine;
- exhaust pipe;
- labyrinth seals;
- bypass valve ;
- oil level indicator;
- motionless bearing;
- loose bearing;
- suction chamber;
- oil drain;
- exhaust channel.
The rotor shaft bearings are located on two side surfaces. In order to ensure uneven thermal expansion between the piston and the housing, they are designed as stationary bearings and sealing inner rings from different sides. The bearings are treated with oil that is pumped out of the mud flaps. The drive shaft is brought out and isolated by the rings of the radiator shaft.
The rings are made of fluororubber, and then lubricated with sealing oil. The rings located on the sleeve are necessary to protect the shaft; by the way, they can be replaced if necessary. If a tight seal is required outside, the equipment can be set in motion by means of a coupling with a cup and magnets.
VVN and the principle of its functioning
The principle of operation of the BBH vacuum pump is also based on creating an environment for aspirating vapors and gases. The main unit of such devices is a round drum, in which there is a rotor with blades. When the rotor begins to rotate, water is pressed against the walls of the drum under the action of centrifugal force. As a result, a ring is formed.
The rotor is located away from the center, due to this a cavity is formed under it, which is divided into cells of different volumes. When the cell is on the edge of the cavity, it has a small volume, which is called the suction window. However, during rotation, the volume increases, and in this condition gas is sucked in. The volume becomes maximum, and the rotor makes another circle. From this it is clear that the principle of operation in this case is based on centrifugal force.
The principle of operation of the vacuum pump for the engine
The principle of operation of the vacuum pump of a diesel engine may interest the car enthusiast. If we compare with gasoline engines, where there is a throttle valve and the possibility of creating a vacuum for use with different purposes, the diesel engine does not have a throttle valve, as well as the possibility described above. Therefore, in diesel engines, a pump is used to create a vacuum. It is complemented by an eccentrically mounted rotor with a moving plastic blade dividing the cavity into two parts.
Additional nuances
When the rotor rotates and the blades move in it, one part of the cavity increases in volume, while the other part decreases. Air intake from the vacuum system occurs on one side of the suction, and after that the air is forced out through the channel.
It is used to cool structural components. Oil is supplied through the channel, runs along the cylinder head, and then enters the pump. Oil is used not only for lubrication, but also for sealing the blades in the working cavity. The drive is carried out from the crankshaft and camshaft, in the latter case, the pump is combined with the fuel priming pump of the system.
The principle of the water pump
The principle of operation of a vacuum pump for water is the displacement process. During operation, water is pumped out as a result of changing the parameters of the working chamber. The vacuum volume is associated with the level of tightness of the working space, which is regulated, which allows you to reduce or increase the pressure in a certain place to the desired value.
A water vacuum pump, the principle of operation of which may be of interest to the consumer, usually has a cylindrical shape. Inside is an impeller or shaft with a wheel, which has special blades. The impeller acts as the main element. The wheel rotates in a housing that is filled with working fluid. As a result of rotational movements, the blades capture water, which spreads along the walls. A centrifugal force arises , provoking the appearance of a ring from a liquid. Inside, a free space forms, which is called a vacuum.
Features of the vacuum pump
Vacuum water pumps have certain features, among them are:
- low noise and vibration;
- high performance;
- high structural strength;
- good speed of water supply and injection;
- high starting pressure;
- environmental friendliness.
An additional distinguishing feature is isothermal sealing. The unit perfectly copes with the pumping of gases and vapors, and is also able to drain liquids, doing this at the same time. Quite often, such equipment has an integrated dirt separator.
The principle of operation of a rotary vane pump
Rotary vane vacuum pumps, the principle of operation of which is to displace the action, is an equipment with an oil seal. The system includes:
- housing;
- blades;
- eccentrically mounted rotor;
- entrance and exit.
The oil seal is installed on the exhaust valve, which is designed in the likeness of a vacuum safety valve. In the process, he is in an open state. The working chamber is located inside the housing, and the rotor blades divide the chamber into two compartments, different in volume. As soon as the device is turned on, gas will enter the expansion chamber until it is blocked by a second blade.
What else to know about rotary pump operation
The gas inside is compressed until the pressure relief valve is open. If gas ballast is used, an external opening is opened through which gas is discharged into the suction chamber located on the front side. Such equipment also has a second name - oil vacuum pump, the principle of operation of this device has been described above. The working fluid is oil, which performs several functions. It lubricates the moving parts and fills the space under the exhaust valve. The narrow gaps between the outlet and the entrance are filled with oil. The working fluid seals the gap between the working chamber and the blades, ensuring optimal temperature balance due to heat transfer.
Conclusion
Vacuum pumps can also be classified according to the physical principles of work on gas-binding and gas-transporting. The latter transport particles or displacement. Some varieties of vacuum pumps assume a molecular flow of the substance being transported, while others suggest a laminar flow. If we are talking about mechanical pumps, then they can be divided into molecular and volumetric.