1, first of all to understand the type of vacuum pump , features, the current situation. Understand the requirements, determine the repair target. Before testing, prepare for testing.
2, to determine the vacuum pump failure, diagnosed the fault. Judgment, may save trouble. Confirmed to verify.
3, ruled out pump failure, the first simple and complex, the first easy hard. Do not disassemble without demolition. To reduce the lack of special tools and improper operation caused by new damage, reduce the position changes and run-in time. In general, the splicing rotor is not removable, otherwise the form of tolerance can not be guaranteed, the rotor scrapped.
4, toxic and harmful, corrosive vacuum pump, should be asked to clean the user first, and inform the necessary protective measures to protect the health of maintenance personnel.
5, dry vacuum pump fault classification suggested that the fault is divided into operational failures and performance problems.
Operation failure can include pump does not turn, the pump temperature is too high, oil spills, water leakage, the maximum power exceeded.
Performance failure can include the ultimate pressure, extreme pressure, suction efficiency, noise, fuel injection, gas town performance, etc. can not meet the requirements or not.
6, fault diagnosis and diagnostic examples (1) the vacuum pump does not turn. Unidentified can not open the pump, so as not to aggravate the fault. Can be used to move hands and can not move.
â‘ vacuum pump can move without rotation. The reason can be coupling failure; belt slippage; motor wiring is wrong; motor damage; no power and so on.
â‘¡ can not panic or plate up very heavy, the reason can be because the starting pump temperature is too low, the pump oil viscosity is too high; design and manufacture of pump stop too much oil. Too much oil caused by the pump back to the oil too much (too much fuel, or water vapor condensation in the pump, or condensate in the exhaust pipe back to the pump); foreign matter in the pump (intake manifold welding Slag, oxide; Rotor spring and other pump parts debris; Rotary deformation stuck; occurred occlusion (copper sleeve, rotor, the wall, pump cover, stator, bearings).
(2) vacuum pump temperature is too high. Refers to the lowest measured near the exhaust valve exceeds the maximum oil temperature specified in the manual. As the pump temperature will increase the viscosity of the pump oil dropped significantly, and to increase the saturated vapor pressure of the pump oil, the pump to increase the pressure limit and reduce the suction efficiency; rubber parts easy to aging; thermal expansion of the operating gap narrowed, especially Is the thickness of some non-metallic rotary vane and copper sleeve hole clearance, affecting the reliability of pump operation. Pump temperature is too high because the pump ambient temperature is too high, the intake air temperature is too high, the intake air cooling device fails, the pump long-term continuous operation inlet pressure is too high; water cooling pump cooling water is insufficient, the design of circulating water is not good; temperature control Water control valve failure and so on.
(3) imported vacuum pump oil spills. Can occur in the shaft seal, the sealing surface of the fuel tank and pump parts, drain plugs, oil standard, hole stuffy head, stator parts and bearing through-hole connections, gas ballast valve (for example, 2X-8) and other parts. Aging by the seal, improper installation, damage failure, the surface is not flat, there are impurities, rough and loose casting caused. If you stop the pump back to the oil, the oil will enter the gas town valve, the gas valve may not leak gas.
Homemade rubber mat, be sure to use oil rubber, according to the original design shape, sealing surface is too large when the pressure will leak.
(4) Leakage of imported vacuum pump can occur in the water pipe joints, water jacket boring cover plane, drain hole plug, drain valve, etc., water jacket drill wear, casting defects, cracking, may also lead to water leakage.
(5) high power exceeded. Can be long-term continuous for the inlet pressure is too high, the exhaust pressure is too high, debris into the occlusion occurs, the pump temperature is too high, the rotary vane with the gap is too small, the voltage is too high, too much pump back into the pump caused, Will damage the motor. Should try to avoid long-term continuous operation near the maximum power. If there is sediment on the surface, remove it regularly.
(6) Dry pump ultimate pressure is not up to standard.
It can be caused by external leakage, internal leakage, oil hole blockage, poor or deteriorated pump oil quality, condensable substances such as water vapor, distortion of instrumentation and abnormal operation of vacuum pump.
More leakage, the exhaust can see the white steam. There are more bubbles at the oil mark, hand exhaust pressure on the exhaust can feel. Low-level exhaust valve at the surface there are more bubbles. Power will increase. At this time, first check whether the gas ballast valve is closed. As the new pump factory in the pump each port to measure the ultimate pressure, so if the leakage phenomenon, the pump port and piping, valves, containers one by one inspection. Outer shaft seal failure, oil cup oil-free, gas-filled head can also cause leakage. The internal leakage can be caused by the movement gap in the pump, the plane of the exhaust valve seat, the sealing surface of the exhaust valve, the inner shaft seal, the plane of the pump cover, the air inlet pipe and the gas valve seal. Wear, corrosion, bite will increase the operating gap. When the oil hole is blocked, open the oil hole to hear the noise of the pump will be lighter. If the oil seal is good, the exhaust valve may fail if the hand is sucked on the exhaust port.
If the vacuum pump oil clean, unused long-term storage, the valve can be opened to purify water vapor pump. If invalid, should check apricot meter. If the pump oil yellow and white has emulsified, the gas can be fully open the town, adjust the atmosphere to purify the operation, if necessary, the amount of gas into the pump port operation, can speed up the purification process. If other volatile gases or liquids are pumped, please change the oil in time and wash the oil tank if necessary. Some pumps, in the interstital airway will be deposited pump fluid, in order to obtain a good oil change effect, to find ways to drain the pump fluid.
The ultimate pressure is measured using a seat compression mercury vacuum gauge.
Measured values ​​increase with a full pressure gauge such as a calibrated thermocouple gauge. Note the regulation of the thermocouple gauge to be paired. It is advisable to back up a calibration that is calibrated at the same time for comparison against any suspected contamination regulation.
Increasing the ultimate pressure will decrease the pumping efficiency during high vacuum and will also raise the ultimate total pressure. Can refer to the above description to determine, check, deal with the decline in pumping efficiency and the ultimate pressure rise of the failure.
(7) Vacuum pump noise. Pump structure design, the motor and pump bearing noise, rotating pieces and other moving parts are smooth, too much oil into the fan, the noise generated by the transmission, a large intake, open air town operation, the oil pan and other pumps Loose parts, inequitable installation caused by vibration, will affect the pump noise.
(8) vacuum pump fuel. To prevent the injection of fuel tank back to the oil hole size, location, sealing conditions, oil retaining plate design, installation, exhaust part of the mist reducer, oil cap, gas separator, the level of oil into the oil The amount of the size, will affect the pump fuel injection, the pump open the door to open the exhaust air, direct pump exhaust air flow rate can be as high as 30m / s, blowing the oil surface, the pump circulating oil and air out of the oil Will test the measures to prevent fuel injection.
7, other. Some vacuum pumps have oil pumps, oil separators, check valves on oil circuits, mist eliminators, inlet filters (for oil vapor return flow), inlet dust filters and other components or accessories, and also for inspection . Pump failure will pump lubrication and seal failure, mist eliminator failure, it is possible to make the exhaust pressure increases, the power increases, damage to the motor, inlet filter failure can increase the intake resistance, pumping speed decline, pumping Decreased efficiency.
8, vacuum pump cleaning. Should not be dipped, so as to avoid the spill into the splicing internal, difficult to discharge.
9, vacuum pump disassembly. In accordance with the use of shouting recommendations and regulations to orderly carried out, remember the location, reasonable display, so as to avoid wrong equipment.Brass Press Fittings
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