A vacuum pump, a device whose working principle will be described below, is equipment that is used to pump and remove vapors or gases to a predetermined pressure level. The latter is also called plumbing vacuum.
The development of vacuum technology starts in 1643. At that time, atmospheric pressure was measured for the first time. In the second half of the 19th century, mankind entered the technological stage of creating vacuum equipment and devices. This was due to the emergence of the mercury piston pump, which happened in 1862.
Working principle
The principle of the vacuum pump is that pumping is provided by changing the volume of the working chamber. Such volumetric pumps are used to obtain a preliminary discharge, which is called a fore vacuum. These include pumps:
- rotary;
- liquid ring;
- reciprocating.
The most popular in vacuum technology are rotary pumps. Ifwe are talking about high-vacuum pumps, then they should include turbomolecular, steam-jet and steam-oil pumps. Molecular pumps are produced by the transfer of gas molecules of movement from a solid, vaporous or liquid surface, the latter of which moves at high speed.
These include ejector, water jet, diffusion, molecular devices with the same direction of movement of surfaces and gas molecules. The same class includes turbomolecular aggregates, in which the movement of solid surfaces of the injected gas occurs mutually perpendicular.
Additionally about the features of the work
If you are interested in the principle of operation of a vacuum pump, 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 units that create a vacuum indicates that almost all devices of this type operate on the principle of displacement, which can be compared with the principle of positive displacement pumps. They are used to pump out the decomposition products of various mixtures and water.
The vacuum created, or rather its value, depends on the tightness of the space, which occurs due to the operation of the pump mechanisms, among them should be highlighted:
- wheels;
- special inserts;
- spools.
The principle of operation of the vacuum pump is that the unit must fulfill two conditions, the first of which is expressed ina decrease in pressure in a closed space, while the second consists in the fulfillment of the previous condition for a certain period of time. However, it is important that the sequence of conditions be preserved.
When the gas medium is taken up by the equipment, and the pressure is not reduced to the desired value, then the use of a forevacuum apparatus will be required. This, in turn, will reduce the pressure of the gaseous medium. This principle implies the possibility of serial connection of pumps.
The principle of operation of the vacuum pump should involve the use of vacuum oil, which eliminates gas leakage through the gaps of 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. These pumps can be categorized as positive displacement rotary vacuum pumps that run dry. Among the main components of the equipment should be highlighted:
- engine;
- outlet;
- labyrinth seals;
- bypass valve;
- oil level indicator;
- fixed bearing;
- loose bearing;
- suction chamber;
- oil outlet;
- exhaust channel.
Shaft bearings are located on two side surfacesrotor. In order to ensure uneven thermal expansion between the piston and housing, they are designed as fixed bearings and sealing inner rings on different sides. The bearings are treated with oil, which is injected from the mudguards. The drive shaft is brought out and insulated with rings of the radiator shaft.
The rings are made of FKM 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 an airtight seal is required from the outside, the equipment can be driven using a clutch with a cup and magnets.
VVN and how it works
The principle of operation of the VVN vacuum pump is also based on creating an environment for the suction of vapors and gases. The main unit of such devices is a round drum, in which there is a rotor with blades. When the rotor starts to rotate, the 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 away from the center, thanks to this, a cavity is formed under it, which is divided into cells of different volumes. When the cell is at 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 oncentrifugal force.
The principle of operation of the vacuum pump for the engine
The principle of operation of a diesel vacuum pump may be of interest to a motorist. Compared to gasoline engines, where there is a throttle and the ability to create a vacuum for use with different purposes, a diesel engine does not have a throttle, 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 blade moves in it, one part of the cavity increases in volume, while the other part decreases. The intake of air from the vacuum system occurs on one suction side, and then the air is forced out through the channel.
It is used to cool structural components. Oil is supplied through the channel, goes along the cylinder head, and then enters the pump. Oil is used not only for lubrication, but also for sealing the blade 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 working principle of vacuum water pump is the processdisplacement. During operation, water is pumped out as a result of changing the parameters of the working chamber. The volume of vacuum is related to the level of tightness of the working space, which is adjustable, which allows you to reduce or increase the pressure in a certain place to the desired value.
Water vacuum pump, the working principle of which may be of interest to the consumer, as a rule, has a cylindrical shape. Inside is an impeller or a shaft with a wheel that has special blades. The impeller acts as the main element. The wheel rotates in a housing that is filled with a working fluid. As a result of rotational movements, the blades capture water, which spreads along the walls. There is a centrifugal force that provokes the appearance of a ring from the liquid. Free space is formed inside, which is called a vacuum.
Features of the vacuum pump
Vacuum water pumps have certain features, among them should be highlighted:
- low noise and vibration;
- high performance;
- high structural strength;
- good water supply and pumping speed;
- high starting pressure;
- sustainable.
An additional distinctive feature is isothermal sealing. The unit perfectly copes with the pumping of gases and vapors, and is also able to remove liquids, doing it at the same time. Quite often, such equipment has a built-in dirt separator.
Working principle of rotary vane pump
Rotary vane vacuum pumps, which work on the principle of displacement action, are oil-sealed equipment. The system consists of:
- case;
- blades;
- off-center rotor;
- entry and exit.
The oil seal is installed on the exhaust valve, which is designed like a vacuum relief valve. During operation, it is in the open state. The working chamber is located inside the body, and the rotor blades divide the chamber into two compartments, different in volume. As soon as the device is turned on, the gas will flow into the expansion chamber until it is blocked by the second blade.
What else you should know about rotary pump operation
The gas inside is compressed until the pressurized release valve is opened. If a gas ballast is used, an external opening is opened through which the gas is released into the suction chamber located on the front side. Such equipment has a second name - an oil vacuum pump, the principle of operation of this device has been described above. Oil acts as a working fluid, which performs several functions. It lubricates the moving parts and fills the space under the exhaust valve. Filled with oil and narrow gaps between the exit and the entrance. The working fluid seals the gap between the working chamber and the blades, ensuring optimal temperature balance through heat exchange.
Conclusion
Vacuum pumps can also be classified according to physical principleswork on gas-binding and gas-transporting. The latter transport the particles or the working volume. Some types of vacuum pumps assume the molecular flow of the transferred substance, others - laminar. If we are talking about mechanical pumps, then they can be divided into molecular and volumetric.
