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How to reduce the maintenance rate of vacuum system?
Time:2019.04.01 Source: Yuhuan Tongzhou Machinery Co. ltd. Clicks:
How to reduce the maintenance rate of vacuum system?


The key point of maintaining vacuum system is to judge the fault. Vacuum can not be pumped up, there may be several reasons, it is necessary to find out what is the reason.


Whether the suction capacity of vacuum unit is insufficient or the leakage rate is high; or both, the vacuum system needs to be patiently observed and recorded to find out the causes of the failure. For example, the suction time is the same, but the vacuum degree is low. At this time, the sealing of high pressure valve, such as the vacuum meter pointer drops rapidly, most of the environment is a vacuum chamber leakage, leakage should be detected first. If the vacuum gauge pointer drops very slowly, most of the environment is insufficient pumping capacity of the vacuum unit, then it will be put on the problem of finding the vacuum pump and valve to see where the leakage occurs, or the diffusion pump oil is polluted and oxidized, or the front pipeline is not well sealed, the pump oil is insufficient, or the pump has oil emulsification, shaft seal oil leakage, valve piece damage and other faults.


The problem of leak detection is a headache for users in vacuum system maintenance. The leakage points are internal and external; the external funnel is good for detection, but the internal funnel is more difficult. The larger leakage point can be made by flame method. The reason that operating air flow can make the flame deviate is that vacuum should be pumped first, and then candles or lighters should be used to search slowly near the suspicious point. It will be found that the flame deviates from the leakage point and the leakage point can be found. Internal leakage should be checked from different vacuum working areas. After the vacuum system reaches the necessary pressure value, the winding and evaporation system should be started separately to check whether the reading of the vacuum gauge has climbed after a short decline, so that the purpose of the internal leakage mark can be preliminarily judged. Internal leakage mostly occurs in equipment with water cooling point. No doubts have been found in leakage inspection. However, there are the following phenomena: the pumping speed of mechanical pumps is relatively low, the indication value of vacuum gauge is low, the oil of mechanical pumps is quickly emulsified, and the iron-based parts in vacuum chambers are corroded. With the above conditions, the internal leakage can be estimated. First, the cavity is cleaned up, then the cooling water is opened, and the water pipe is carefully inspected. Whether the road is wet or not, the wet part is the leak point.


The problem of leak detection is a headache for users in vacuum system maintenance. The leakage points are internal and external; the external funnel is good for detection, but the internal funnel is more difficult. The larger leakage point can be made by flame method. The reason that operating air flow can make the flame deviate is that vacuum should be pumped first, and then candles or lighters should be used to search slowly near the suspicious point. It will be found that the flame deviates from the leakage point and the leakage point can be found. Internal leakage should be checked from different vacuum working areas. After the vacuum system reaches the necessary pressure value, the winding and evaporation system should be started separately to check whether the reading of the vacuum gauge has climbed after a short decline, so that the purpose of the internal leakage mark can be preliminarily judged. Internal leakage mostly occurs in equipment with water cooling point. No doubts have been found in leakage inspection. However, there are the following phenomena: the pumping speed of mechanical pumps is relatively low, the indication value of vacuum gauge is low, the oil of mechanical pumps is quickly emulsified, and the iron-based parts in vacuum chambers are corroded. With the above conditions, the internal leakage can be estimated. First, the cavity is cleaned up, then the cooling water is opened, and the water pipe is carefully inspected. Whether the road is wet or not, the wet part is the leak point.


Speaking of the possible giant here, it seems that leak detection is not so difficult. Why is it a headache? In fact, the big leak is not difficult to find, the hard thing is the small leak and the slight leak.


The ionization tube can be operated under high vacuum to detect leaks by reacting sensitively to certain gases, such as acetone or ethanol, injecting acetone or ethanol into suspicious places with a needle punch, connecting the pointer vacuum gauge, when it sprays to the leak point, the pointer of the ionization gauge will oscillate relatively. In this way, the leak detection must be patient, until the indication of the ionization gauge is unchanged, that is, the vacuum unit. The suction capacity and leakage rate are balanced, then spray, repeated several times to confirm the leakage point.


Maintenance must pay attention to several links, such as disassembly, cleaning, grinding and assembly. Vacuum system belongs to compact mechanical equipment regardless of its size, which is very important. Disassembly should follow the principle of light handling and light handling, not brutal work, must not be hammered; cleaning parts should be clean, in order to find problems and detect hidden dangers; vacuum system products and general mechanical products are quite different, general mechanical products are chamfered chamfered, and vacuum pump corrugated angle is clear, very easy to hurt hands, should be more careful, remember.


Checking the leak point is a meticulous work. Don't drop every detail, let alone have a chance mentality. Often a manufacturer comes to ask for help and checks everything he says. It means that the vacuum can't go up. Maybe it's a vacuum hose for air supply that hasn't been checked, or a water joint. Problems often arise inadvertently at the moment.


Maintenance should not be done too quickly. If the fault is not clear, it will start to disassemble. It will add new diseases to the old ones and complicate the original simple problems.


Many manufacturers have asked that routine maintenance can be done on time, equipment failure under emergency conditions of vacuum system, production tasks are urgent, how to deal with this environment? At this time, as long as the fault is judged, the existing materials on hand, such as vacuum sealing mud, vacuum sealing wax, 704 silica gel, vacuum chamber board and other available materials, as long as it does not occur with finished products. Conflict can be repaired. The principle of emergency response is to ensure the normal production of equipment without damaging equipment and without affecting finished products.
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