Why don't limit of vacuum pump vacuum stability _

today, our company's small make up to introduce you to vacuum pump repair the vacuum degree of instability. First of all, let's take a look at what is limiting vacuum. Ultimate vacuum refers to pump can achieve the minimum at the stable operation of the vacuum pressure. Shortly after the open, pump can achieve the lowest pressure range. In the vacuum pump running after a period of time, temperature will rise and lead to lubricant pump. Saturated vapor pressure and viscosity changes and extreme performance parameters, such as vacuum pressure has some small fluctuations, but after a period of time after the operation, its stable vacuum pressure values. The stability of the value is the ultimate pressure of vacuum pump we usually said.

vacuum pump repair what are the factors limiting vacuum of vacuum pump instability?

there are many factors contributing to the instability of vacuum pump pressure, such as pumping time, lubricating oil, the machining accuracy of pump itself, the gap between the pump parts and the harmful space adjustment.

1。 Vacuum pump oil's influence on the vacuum pump

for the height of the vacuum pump oil, the oil pump cycle. Rotary vane pump circulating oil amount is large, the better sealing effect, the lower limit pressure; However, due to the vacuum pump running in the process of rotary vane pump vacuum pump oil extreme pressure of air and water vapor release, so the quantity of circulating oil is not possible, there should be an appropriate value.

among them, under ideal conditions, Swallows gas) does not relieve air and water , the relationship between the cycle of oil and extreme pressure, namely vacuum pump oil is higher, the lower limit pressure; Main consideration is in the vacuum pump oil and extreme pressure release of air and water vapor. With the increase of circulating oil quantity, this relationship is higher and higher. When the oil reaches a certain value, the lowest limit pressure, and then increased with the increase of oil increase.

with the rise of the vacuum pump oil, the oil saturation vapor pressure increases, the volatile gas oil will increase, which greatly increased the limit of the rotary vane pump pressure, so should as far as possible to reduce the oil temperature. Reducing the pressure of the limit of the rotary vane pump. Currently used methods mainly include oil pump with air or water cooling, and the increase of the radiator.

2。 Clearance on the influence of the vacuum pump pressure limit

vacuum pump is refers to the vertex clearance and cross section of space. Clearance has a great influence to the limit of the vacuum pump pressure. The existence of the gap is inevitable, it has to do with vacuum pump the machining precision and assembly precision in the process of production, also is the need of functional design. If the clearance is too large, vacuum pump of high pressure chamber of the gas will leak to the low pressure chamber, which will seriously affect the limit of the vacuum pump pressure. Although small gap will decrease the limit pressure of vacuum pump, but can lead to friction increases, which leads to the power, wear and heat dissipation. Series of problems. Therefore, to determine the reasonable gap is very important. Clearance value is not as small as possible. Under normal circumstances, in addition to consider lubrication and leakage, clearance should also be considered the value of the thermal expansion.

3, harmful space effect on the vacuum pump pressure limit

the presence of harmful space also increases the ultimate stress of vacuum pump. Harmful space refers to the point of contact with the stator rotor cavity of the vacuum pump at the end of the space between the stator and vent, and the space of the gas discharge from the vent. The end of the cycle. Under the compression of rotary vane rotation, overflow, from the point of contact gap from the vertex spilled into the suction chamber, so as to improve the limit pressure of the vacuum pump. This can be achieved by oil filling the danger zone or introduced in space on the side panel of the gas channel ( Used for the dry lubrication pump) To solve it.