Due to the distinctive performance and convenient design, the vane pump has become widespread in various industrial fields. It is used in the pharmaceutical, chemical, cosmetics and food industries - for pumping condensed milk, molasses, glaze.
The design includes a heating jacket for pumping substances that become thick at low temperatures. The vane pump is used to move many types of liquids: mushy, abrasive, with the presence of foreign small particles, as well as resins and adhesive masses based on them. It is possible to use for pumping out through a hose, by lowering the intake pipes into the tank. This device, unlike other types, has an increased suction capacity and works with equal force in both directions.
Design
Basisvane pump is as follows:
- Case with easy-to-disassemble device made of durable steel grade.
- A geared motor having an asynchronous powerful motor.
- A shaft with plates moving along an eccentric path, they are made of bronze or its food substitute.
Next to the grooves on the cylindrical surface in the direction of rotation, recesses are made with different angles of inclination at the points towards the exit of the faces.
Application
The vane pump, the average price of which is 30-40 thousand rubles, is a hydraulic machine with volumetric displacement and working moving blades with reciprocating motion with respect to internal elements. It is used as a stationary and mobile unit in mechanical engineering, as well as in agriculture. When pumping liquids with foreign particles, it is important to consider that if the permissible particle size is exceeded, they can be retained by the filter on the nozzle.
Vacuum vane pumps are produced with the right direction of shaft movement. It is allowed to manufacture with the left direction on an individual order. The mechanism is installed in any position. The flexible coupling connects the drive shaft and the pump shaft. It is not allowed to transfer axial and radial loads from the drive.
Features
As practice shows, difficulties in extending the period of work are associated with damage to workersplates damaged by interaction with abrasive particles that are in the pumped mass. A rotary vane vacuum pump has been created for pumping liquids of various types, it has a body with a profiled plane, with discharge and intake windows. Among the shortcomings, it is worth noting the decrease in reliability indicators during the pumping of masses with foreign inclusions and various impurities. The transported medium in the course of work passes to the pressure nozzles from the retractors, while foreign particles stick to the plane of the rotor and housing. If the dimensions of the elements present in the liquid exceed the maximum allowable limit, there is a possibility of damage to the rotor of the device and the inner surface.
A vane NPL pump with discharge and absorption windows on the internal surfaces has a more advanced design. This device has a rotor with grooves, special plates are installed in its cavities, moving in the radial direction. The disadvantage of this design is the uneven wear of the surface of the plates, the inner cover, the housing. The rear working edges and edges wear out unevenly due to pressure drops in the opening chamber and the pressure channel during the transition of the plate to the pattern area. In addition, it is worth noting the damage caused by large particles entering the gaps between the parts that were not caught by the channel filter.
The cost of this type of pump starts from 42,000 rubles, it is designed for use in metal-cutting hydraulic machines and other devices in whichflow of working fluids is required, not adjustable in magnitude, with a stable pressure.
What is required for installation
A safety valve is mounted to protect the hydraulic system and pump from overload. At the same time, its settings must correspond to the nominal outlet pressure. The pipeline must have smooth bends and a good seal at the junction with the pump to exclude the possibility of air ingress.
The working mass is poured into the mechanism before the first start, and the valve screw is unscrewed to zero settings.
Features
Rotor vane vacuum pump is evaluated by the following properties:
- Pumping speed, detected by the volume of gas that passes through the section of the nozzle at nominal pressure. If the pressure in the system changes, then the same thing happens with the pumping speed. The dependence of the speed of action on pressure reveals the feasibility of using the device at a given level of pressure.
- Outlet maximum pressure from the outlet side. Its excess contributes to an increase in pressure in the inlet section. Some oil vane pumps do not emit exhaust gas into the atmosphere. Accordingly, in order to maintain normal operation, a pre-vacuum must be formed - this is the minimum pressure achieved by this device.
Mechanism types
In many waysdetermines the principle of operation of the mechanism, the nature of the movement of gas in the working pressure range. The gas flow, depending on the rarefaction, is carried out in the molecular, viscous or inertial regime. The pump can be double acting or single acting. In the latter case, a cycle of work occurs in one revolution, which includes the process of suction and discharge. There is also a division into unregulated and regulated. In the first variant, the mechanism can provide a continuous direction of fluid flow, in the second, a mechanical adjustment of the valve is required. A single acting vane pump can have two types of mechanisms. In double modifications, there is only an unregulated device.
Dignity
Among the positive points worth noting are the following:
- Easy maintenance.
- Increased reliability.
- Reversibility.
- Durability.
- Virtually silent operation.
- Easy installation.
- Economical.
Oil pump assembly
Spool, lamellar-stator and rotary variants have become widespread. The vacuum rotary vane pump has an eccentrically rotated mechanism, two plates are located in the cavities of which are pressed against the surfaces of the housing. The working volume of the chamber is divided into predetermined parts by the points of contact of the rotor, plates and walls, in particular, into an intermediate one, which reduces the mass of the inlet and increases when moving. On the intake side, with an increase in volume, rarefaction appears, and the gas from the chamber enters the vacuummechanism. The gas on the intake side begins to compress and is expelled when the pressure of the valve spring is exceeded. The body of the mechanism is located in a container with oil, due to which all gaps are sealed and the possibility of gas backflow is excluded.
Oil types of vane pumps are not designed for pumping vapor-gas mixtures, for example, moist air. Due to design features, the gas is compressed by the time the exhaust valve opens. In this case, steam even with a small partial pressure in the chamber begins to condense, water mixes with oil and ends up on the inlet side, where it evaporates again. This is how the cycle happens.
Gas ballast
The oil pumps use gas ballast mechanisms to expel moist air, which feed atmospheric dry air into the compression volume. The ballast gas causes the exhaust valve to open before the partial pressure reaches the dew point, after which both vapors and gases are released. The gas ballast reduces the ultimate vacuum and reduces the speed of action, but at the same time the range of application of the device is increased.
The vane pump requires the use of vacuum speci alty oil, which eliminates low-boiling fractions through the use of vacuum distillation. In places of friction, due to overheating during operation, decomposition of the oil begins, subsequently light hydrocarbons appear. They reduce vacuum and increase vapor pressure.
