A micro-vacuum pump common sense The so-called vacuum, refers to the pressure in a given space, below 101325Pa gas state. In a vacuum, the leanness of a gas is usually expressed as the pressure of the gas. Obviously, the lower the pressure, the thinner the gas. There are a variety of industrial vacuum pumps, for a variety of pump performance test methods have the provisions of the test, the main parameters are: 1. Suction rate: at the vacuum pump suction port, the unit of time flowing gas volume. Traditional industrial vacuum pump volume is generally large, and the pump work requires special vacuum pump oil and lubricating oil, medium gas will contain a lot of oil mist. 2. Ultimate vacuum (often referred to as vacuum): the vacuum pump connected to the test container, into the gas to be tested after a long time continuous extraction, when the gas pressure in the container does not continue to decline and maintain a certain value, This pressure is called the pump's ultimate vacuum. The smaller the value, the closer it is to the theoretical vacuum. With the development of instrumentation industry and people's environmental protection requirements, the miniature oil-free vacuum pump came into being in various countries, generally have the following rules: The price of the pump is closely related to the vacuum index. The degree of vacuum indicator is the major indicator pursued by manufacturers in various countries. It reflects the overall strength of corresponding mechanical processing, sealing technology, material science and other fields, and is also an important means for manufacturers to obtain profits. To increase the vacuum index, there must be a higher sealing conditions, so you need to use more precise size, material properties and more excellent parts, so the production cost is greatly increased. And the price increase is much larger than the increase of vacuum index. Of course, the increase in pumping rate will also cause the price to rise, but its rate of increase is small. Therefore, the choice of micro-vacuum pump need to seriously consider the vacuum index, the rate of exhaust indicators, their own use, etc., so as to best use both performance and cost. High vacuum degree of micro-pump due to the use of a very precise sealing parts, so it's working conditions of the cleaning conditions, temperature parameters, medium composition and so have higher requirements. Vibration and noise. Pump pumping speed and vacuum higher, the greater the vibration and noise. Second, the vacuum unit to explain There are two commonly used methods for the identification of the degree of vacuum, one is to identify the absolute pressure (ie, absolute vacuum), and the second is to use relative pressure (ie, relative degree of vacuum) identification. The so-called absolute pressure refers to the vacuum pump connected to the test container, after sufficient time for continuous suction, the pressure in the container no longer continue to decline and maintain a certain value, then the gas pressure in the container is the absolute pressure of the pump. If there is absolutely no gas in the container, then the absolute pressure is zero, which is the theoretical vacuum. In the actual situation, the absolute pressure value of the vacuum pump is between 0 ~ 101.325KPa. The absolute pressure value needs to be measured with an absolute pressure meter. At 20 ° C and altitude = 0, the initial value of the meter is 101.325 kPa. Relative vacuum refers to the difference between the pressure of the measured object and the atmospheric pressure at the measurement site. Measured with an ordinary vacuum gauge. In the absence of a vacuum, the initial value of the table is zero. When measuring vacuum, it has a value between 0 and -101.325 kPa (typically expressed in negative numbers). For example, a measured value of -30 kPa indicates that the pump can be pumped to a vacuum of 30 kPa lower than the atmospheric pressure at the measurement site. The same pump measured in different locations, the relative pressure values ​​may be different, because the different measurement sites atmospheric pressure is different, which is around the altitude, temperature and other objective conditions caused. International vacuum industry is the most common, but also the most scientific is the use of absolute pressure identification; due to the relative degree of vacuum measurement method is simple, non-universal measuring instruments, easy to buy and cheap, so it is also widely used. Of course, in theory, the two can be converted to each other. The conversion method is as follows: Absolute pressure = pressure at the measurement site - the relative pressure of three. About the difference between miniature vacuum pump and gas sampling pump 1. Usually we can produce a negative pressure of the small volume pumps are called miniature vacuum pump, but the product selection But we must strictly distinguish. 2. The true sense of the miniature vacuum pump (such as PK, PC series, etc.), is a long time for the closed container vacuum pump, it can drive a larger load. The gas sampling pump (such as PM, PB series, see details) working pressure pump inside and outside the smaller, so it with a very small load. It is because of the different requirements of load capacity, resulting in micro-vacuum pump and gas sampling pump parts are very different. 3. Miniature vacuum pump diaphragm and motor have high requirements. For the two main parts, the fatigue strength, reliability, life expectancy and other technical indicators are required to meet the conditions of the load, unlike the gas sampling pump only required at very light load standards (test proved that the load is slightly larger Gas sampling pump is easy to damage). Therefore, the cost of the two micropumps varies greatly. 4. To sum up, if the miniature vacuum pump is used for gas sampling, it is bound to obtain high reliability and longer service life, but the cost is too high. If the gas sampling pump is used in a slightly larger load, the reliability life On the big discount, or even unable to work, although it has greater cost advantages. Selection is best to consult the technical department clearly, so as to take into account cost and performance. Some gas sampling pump can achieve better vacuum and flow indicators. However, it is two different things to achieve this technical indicator and to be able to work reliably for a long time under this indicator. For example, a miniature pump, can reach 30KPa vacuum, then when the pump suction port often at this degree of vacuum, the vacuum pump can work reliably? Therefore, the vacuum pump can reach the target and reliable indicators of its work is not the same, please confirm to the manufacturer or dealer to confirm.
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