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Requirements of vacuum pump for lubricating oil

In fact, the factors that affect the vacuum degree of vacuum pump are various, including sealing mode, clearance of accessories, material quality and so on. This paper mainly explains the requirements of vacuum pump for lubricating oil.

(1) With appropriate viscosity: the viscosity of oil is too small, the lubricity can not meet the requirements, the sealing is not good, the viscosity is too high, the internal friction is large, the rotor rotation is difficult, the kinetic energy consumption is increased, and the oil temperature is also increased. The increase of oil temperature will accelerate the oxidation deterioration of oil, especially for rotary vane vacuum pump.

(2) Low saturated vapor pressure: the “vapor pressure” index of oil is low, so it is not easy to evaporate under the working conditions of low pressure and high temperature in the vacuum pump, so as to ensure the required vacuum degree.

(3) The oxidation stability is good, and the oil in use is not easy to oxidize and deteriorate.

Generally, vacuum pump oil is selected for vacuum pump. At present, there is only No. 1 vacuum pump oil made in China. It is made of natural crude oil and refined deeply. It plays the role of lubrication and sealing in vacuum pump.

Installation and use of rotary oil pump

When installing the rotary pump, certain rules must be observed: the pump with small displacement (moving plate and fixed piece type) should be fixed on a considerable base, and when installing the pump, it should be considered that the use process is easy to access, so as to observe its working conditions and replace new oil.

Piston pump should be installed on the foundation and fixed with bolts, nuts, washers and lock nuts. After installation, the pump must be cleaned with clean cloth.

Before starting the pump, it must be washed with vacuum oil, and then injected with the required amount of pumping. When the pump motor and circuit connected, must be sure that the motor belt rotation direction is correct.

To do this, the drive belt must be removed from the pulley of the pump, and then the motor is switched on. If the rotation direction of the motor pulley is consistent with the direction indicated by the pointer on the pump cover, it is correct to turn on the motor (if it is standing against the motor, its pulley should rotate clockwise).

After the motor stops rotating, put on the drive belt, tighten it with the fastening bolt on the sliding plate, and finally fix the motor firmly (at this time, the intake pipe of the pump should be sealed).

After that, the pulley of the pump must be rotated by hand for several turns, and then the pump is turned on, and the limit empty caused by the pump is measured. In order to prevent the oil from splashing out of the pump, do not switch on the pump at once, but turn on the motor intermittently several times in a short time interval, and the rotation of the pump rotor is not greater than half revolution in each time interval.

There are two reasons for the excessive heating of plunger pump, one is the heat generated by machine friction. Because the active surfaces are in the state of dry friction or semi dry friction, the moving parts rub against each other to generate heat. Second, liquid friction heat. High pressure oil leaks into low pressure chamber through various loopholes, and a large amount of hydraulic energy is lost and converted into heat energy. In order to accurately select the clearance between moving parts, oil tank volume and cooler, the signs of excessive heating and oil temperature of the pump can be eliminated. In addition, the blockage of the return oil filter causes the return oil back pressure to be too high, which will also cause the oil temperature to be too high and the pump body to overheat.

The main reasons for oil leakage of plunger pump are as follows: (1) the main shaft oil seal is damaged or the shaft has defects and scratches; (2) the internal leakage is too large, which causes the pressure at the oil seal to increase and the oil seal is damaged or flushed out; (3) the oil drain pipe is too thin and too long, which makes the sealing part leak; (4) the external oil pipe of the pump is loose, the pipe is damaged, and the sealing gasket is aged or pregnant with cracks; (5) The bolt of variable regulating mechanism is loose and the seal is broken; (6) there are sand holes or poor welding in cast iron pump shell.

The service life of plunger pump is related to the usual maintenance, the quantity and quality of hydraulic oil and the cleanliness of oil. It is also an effective way to prolong the service life of the piston pump to avoid the wear caused by the particles in the oil.

When replacing parts in maintenance, we should try our best to use the parts produced by the original factory. These parts are sometimes more expensive than other imitation parts, but the quality and stability are better. If we buy the imitation parts with low price, it seems to save the cost in a short time, but it brings hidden dangers and may cause greater harm to the use of plunger pump.

Other related products:
[url=https://www.evpvacuum.com/p-en-68-ZJP_Roots_Vacuum_Pump.html]Roots Vacuum Pump[/url]
[url=https://www.evpvacuum.com/piston-vacuum-pump-structure.html]Piston Vacuum Pump[/url]

Vacuum unit pumping gas containing particles

Vacuum unit is used to pump air and other non condensable and non corrosive gases. It is widely used in various vacuum systems which need high pumping speed and low and high vacuum. It is also the first choice for coarse and medium vacuum systems. For example: vacuum smelting, liquid steel degassing, vacuum sintering, dynamic vacuum acquisition in large-scale space simulation experiment, vacuum impregnation treatment of power capacitor and transformer, exhaust of automatic production line of fluorescent tube and bulb, continuous exhaust of heat preservation bottle, pre extraction of vacuum coating equipment, extraction of magnesium reduction process, degassing of monocrystalline silicon refining process, etc.

If the pumped gas contains solid particles, part of the particles will be discharged from the pump with the gas, and the other part of the particles will continue to rub in the gap in the pump, causing the gap to increase, resulting in the increase of leakage and the decrease of vacuum and gas volume. Therefore, roots vacuum unit is not suitable for pumping gas containing a large number of solid particles, especially solid particles with larger particle size and higher hardness.

The solution to the problem that the gas containing particles must be pumped: if unavoidable, the gas can be purified before entering roots vacuum unit (such as setting filter screen or adding vacuum buffer tank, etc.). If purification is difficult, the particles in the unit should be washed clean after pumping.