Rotary vane vacuum pump is one of the basic vacuum acquisition equipment in vacuum technology. Rotary vane pumps are mostly small and medium-sized pumps. There are two types of rotary vane vacuum pumps: single-stage and two-stage.
The so-called two-stage refers to connecting two single-stage pumps in series structurally. Generally, it is made into a two-stage configuration to achieve a higher vacuum degree. To prevent fuel injection due to oil return and reversal, the pump port should be opened first, and the oil stored in the pump should be manually turned into the tank according to the regulations. At the same time, check the oil level, which should be above the center of the oil gauge, but not full of the oil gauge. If there is too much, it should be drained. Assist in determining steering methods. Place the protective sheath upside down on the pump port. If it is sucked in after starting the pump, it is in the forward direction. If it is blown off, it is in the reverse direction.
Normal sound is positive, abnormal sound is reverse. Suggest dividing faults into operational faults and performance faults. Operation faults may include pump failure, high pump temperature, oil leakage, water leakage, excessive power, etc. Performance failures may include failure to meet standards or requirements for maximum pressure, maximum full pressure, pumping efficiency, noise, fuel injection, and gas ballast performance.
If the situation is unclear, the pump cannot be turned on first to avoid exacerbating the malfunction. Can be turned by hand or not. A、 The pump can rotate without turning. The reason may be a coupling failure; Belt slippage; The motor wiring is incorrect; Motor damage; The power supply is out of battery, etc.
Cannot be turned or turned heavily, the reason may be because the starting temperature is too low and the viscosity of the pump oil is too high; Due to design and manufacturing reasons, there is too much pump shutdown and oil return. Excessive pump shutdown and oil return caused by high oil level (excessive refueling, condensation of water vapor in the pump, or water flow back to the pump due to condensation in the exhaust pipe); There are foreign objects inside the pump (welding slag, oxides in the intake pipe; debris from pump parts such as rotary springs); The rotary blade is deformed and stuck; Occlusion occurred (copper sleeve, rotor, middle wall, pump cover, stator, bearings).
The pump temperature is too high. The oil temperature measured near the low-level exhaust valve exceeds the value specified in the user manual. Due to the increase in pump temperature, the viscosity of the pump oil will significantly decrease, and the saturated vapor pressure of the pump oil will increase, resulting in an increase in the maximum pressure of the pump and a decrease in pumping efficiency; Make rubber parts prone to aging; Thermal expansion enhances the reliability of operation.
The reason for the pump temperature being too high can be due to the high ambient temperature of the pump, the high intake temperature, the failure of the intake cooling device, or the high inlet pressure during long-term continuous operation of the pump; The cooling water volume of the water-cooled pump is insufficient, and the design effect of the circulating water is poor; Failure of temperature control water volume regulating valve, etc. Oil leakage. It can occur on the sealing surfaces of shaft seals, oil tanks, and pump components, oil drain plugs, oil gauges, oil hole plugs, through hole connections between stator components and supports, and pneumatic valves (such as 2X-8).
It can be caused by aging of seals, improper installation, damage and failure, uneven surface, impurities, roughness, and loose castings.
If oil is returned after stopping the pump, it will enter the gas damper, and if the gas damper is not closed, oil leakage may occur. When making homemade rubber pads, it is necessary to use oil resistant rubber and follow the original design shape. If the sealing surface is too large and not tightly pressed, oil leakage may occur.
Water leakage can occur at the head of the water pipe, the flat surface of the water jacket cover, the screw plug of the drain hole, the drain valve, etc. The water jacket may be drilled through, there may be casting defects, frost cracking, and it may also cause water leakage.
Power exceeds the standard. It can be caused by long-term continuous work with high inlet pressure, high exhaust pressure, foreign objects entering and biting, high pump temperature, small clearance between rotating blades, high voltage, and too much pump fluid returning into the pump, which can damage the motor. Long term continuous operation near power should be avoided as much as possible. If there is sediment on the surface, it should be disassembled and cleaned regularly. The maximum pressure is not up to standard. It can be caused by external leakage, internal leakage, oil hole blockage, poor pump oil quality or contamination deterioration, presence of condensable substances such as water vapor, distortion of instruments and meters, abnormal pump operation, etc.
When there is a lot of leakage, white steam can be seen at the exhaust port. There are many bubbles at the fuel gauge, and the hand feels the exhaust pressure on the exhaust port. There are many bubbles on the oil surface at the low-level exhaust valve. The power will increase. At this point, the first thing to check is whether the gas damper has been closed properly. Due to the fact that each new pump is tested for maximum pressure at the pump port before leaving the factory, if there is any leakage, the pump port, pipelines, valves, and containers should be inspected one by one.
Failure of the outer shaft seal, lack of oil in the oil cup, and leakage from the oil hole plug can also cause external leakage. Internal leakage can be caused by wear, corrosion, and biting of the movement clearance inside the pump, the flat surface of the exhaust valve, the sealing surface of the exhaust valve, the inner shaft seal, the flat surface of the pump cover, the intake pipe, and the sealing components of the pneumatic valve, which can increase the operating clearance.
When the oil hole is blocked, open the refueling hole and listen. The pump noise will be relatively light. In the case of a well sealed fuel tank, if there is a feeling of suction on the exhaust port, the exhaust valve may fail.
If the pump oil is clean and has not been used for a long time, the gas damper can be opened to purify the water vapor inside the pump. If it is ineffective, check the instrument panel. If the pump oil turns yellow and white and has emulsified, the gas damper can be fully turned on, and the air damper can be adjusted to purify the operation. If necessary, an appropriate amount of gas can be added to the pump port to accelerate the purification process. If other volatile gases or liquids are drawn in, the oil should be changed in a timely manner, and the fuel tank should be washed if necessary. Some pumps may deposit pump fluid in the inter stage airway, and in order to achieve good oil change results, it is necessary to try to discharge the deposited pump fluid. The ultimate pressure is measured using a seated compression mercury vacuum gauge.
When measuring with a calibrated thermocouple vacuum gauge or other full pressure gauge, the measured value will increase. Note that the gauge of the thermocouple vacuum gauge should be paired and calibrated. It is recommended to have a backup gauge calibrated simultaneously for comparison in case of suspected contamination distortion.