Most of the time, rotary vane vacuum pump is a kind of oil seal pump. In the process of using, part of the oil and gas will be discharged along with the extracted gas, resulting in fuel injection. Therefore, the vane vacuum pump will generally be set at the outlet of the oil and gas separation device. How can users determine if their equipment is in normal condition?

We can test the fuel injection of rotary vane vacuum pump by a simple method.

First of all, we need to make sure that the oil level of the rotary vane vacuum pump meets the specification requirements, and operate the vacuum pump under the limit pressure, and keep the temperature of the vacuum pump stable. Then, a clean white paper is set at the outlet of the rotary vane vacuum pump (perpendicular to the air flow direction of the air outlet) about 200 mm. At this time, the air inlet of the vacuum pump is fully opened to pump air, and observe the time when oil spots appear on the white paper. The time of appearance after measurement is the non injection time of vacuum pump. It should be noted that the continuous operation of the vacuum pump under the inlet pressure of 100KPA ~ 6kpa should not exceed 3 minutes.

At the same time, after pumping air for 1 minute according to the above conditions, stop pumping and observe the oil spots on the white paper. If there are more than 3 oil spots with a diameter greater than 1 mm, the oil injection situation of rotary vane vacuum pump is unqualified.

Injection solution of rotary vane vacuum pump

We know that when the vacuum pump is finished, when it is shut down, Because the pump cavity is in a vacuum state, the pump oil will be returned to the pump cavity. The amount of pump oil is large, some will fill the whole pump cavity, and some can even enter the front pipe. When the pump is started again, a large amount of pump oil will be discharged. After the pump oil is compressed, the temperature rises and the valve plate is impacted. Most of the oil exists in the form of small oil drops, and it is easy to be taken out of the pump under the promotion of large air flow This will cause the phenomenon of pump injection.

To solve this problem, it is necessary to stop the pump at the same time, quickly inflate the pump cavity, damage the vacuum in the pump cavity, so that the pump oil has no ability to recharge. This requires a differential pressure valve at the pump port. However, the speed of gas recharging is very slow, and the function of differential pressure valve is only to prevent oil from recharging to the front section of differential pressure valve, which can not meet the purpose of preventing oil from entering the pump cavity. Therefore, it is necessary to expand the air filling port of the differential pressure valve to make the air flow into the pump cavity quickly, so as to make the gas pressure in the cavity reach the pressure of the pump oil recharging pump cavity in a short time, so as to reduce the oil return volume of the pump cavity. In addition, a solenoid valve can be set at the oil inlet pipe of the pump chamber. When the pump is turned on, the solenoid valve opens to make the oil circuit unobstructed. When the pump stops, the solenoid valve closes the oil circuit, which can also control the oil return.