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Small vacuum pump

Update Time :2017-02-21The view :902

A small vacuum pump is a vacuum pump, the working medium is mainly used for gas, need long-term idle, dry and so on occasions.


Definition


Small vacuum pump refers to the micro vacuum pump, because of the small size of the micro vacuum pump is usually referred to as a small vacuum pump. Micro vacuum pump (i.e. small vacuum pump) refers to a into a suction nozzle and an exhaust nozzle of each one, and can continue to form a vacuum or negative pressure in the inlet; the formation of micro positive pressure exhaust nozzle; the main working medium for gas, an instrument of small volume.

A sealed container (at the beginning of the internal pressure is 100KPa), the micro vacuum pump, continuous pumping on it, the gas pressure in the sealed container will be lower than the atmospheric pressure, reach the absolute pressure of 60KPa. Not only that, after special technical improvements, in addition to the micro vacuum pump single pumping, pumping pump can also form a micro vacuum pump dual-purpose (i.e. the exhaust end can produce relatively large positive pressure), for pressurization, air, and water resistance of the system and overcome the dual micro vacuum pump is very unique, it can the need for long-term idle, dry and so on occasions, unlike the general pump idling, or dry transfer will damage the pump.




Basic principle

The circular motion of the motor, the mechanical device makes the diaphragm inside the pump to do reciprocating motion, thus the pump cavity of fixed volume air compression, stretching to form a vacuum (negative pressure), the pump inlet and the outside atmospheric pressure difference, under the action of the pressure difference of gas pressure (suction) into the pump the cavity is then discharged from the exhaust port.


Selection criteria

First, we must clear the use of micro pump. We divided into three categories one by one.


First, if only by micro pump output of compressed air.

Simply speaking, it is only to cheer, inflatable air pump, the basic need. This situation is relatively simple, according to the output pressure from large to small optional: PCF5015N, FAA8006, FAA6003, FAA4002, FM2002, FM1001. Of course, we must refer to the relevant technical parameters such as traffic indicators.

Two, if the following circumstances, should choose PHW600B or WAA series products.

1, the use of micro pump pumping or vacuum, but sometimes there will be liquid water into the pump cavity.

2, the requirements of the micro pump can pump and pump.

3, the main use of micro pump pumping, but do not want to rely on artificial before pumping water". (some of the pump at work before the need to add some "artificial diversion", this pump to lower the water pumped, otherwise the pump can not be pumped or even damaged.) The advantage of the PHW600B or WAA series is that it does not come into contact with the water, it is evacuated, the formation of a vacuum after the pressure to the pressure up, and then start pumping.

4, with a micro pump pumping, but sometimes it is possible that the pump can not pump water, in the dry turn state. Some traditional pumps are afraid of "dry", even fatal. The PHW600B or WAA series of products is essentially a complex function of the pump, which integrates the functions of vacuum pumps and pumps, it was called "vacuum pumps". Therefore, in the absence of water, it will vacuum, when there is water pumping it. Whether it is pumping or pumping state, are part of the normal work, there is no so-called "dry" damage.

Three, if the use of micro pump pumping, the situation is slightly more complicated.

1, to determine the micro pump suction end condition

There are two types of micro pumps for pumping: gas sampling pumps and micro vacuum pumps. Although it is usually not easy to distinguish them simply referred to as a micro vacuum pump, but from the technical point of view there are two differences, more attention should be paid to selection.

In short, the gas pump can only take a small load (i.e. the pump suction can't end too much resistance, but the price is cheaper); micro vacuum pump in the strict sense can bring large load (pumping end allow large resistance, or even completely blocked), but the price is slightly expensive. The difference between the two can be seen in the article on the micro vacuum pump and the difference between the gas sampling pump, no longer repeat.

The gas sampling pump are: PM series (specific models such as: PM950.2, PM850.5, PM8001, PM7002, PM6503); micro vacuum pump: VM series, VAA series, PK series, PC series, VCA series, VCC series, VCH series, PH series, FM series, FAA series, PCF series, all of these specifications the series is a real miniature vacuum pump, such as VM7002, VAA6005, PC3025 etc..

For the size of the micro pump suction end of the instrument can be measured, and it is the technical parameters of the pump, the inlet allows maximum resistance Por value can be compared to know whether the selection is appropriate. Usually according to the experience of using simple methods, such as the following several cases belong to the high load (i.e. pump end gas resistance), only in the selection of micro vacuum pump range in the pump exhaust end to take long pipe, pipe bending, bending or more severe or even obstruction closed. Or the pipe hole is very small (e.g., less than 2 mm diameter); the throttle valve, solenoid valve, pneumatic switches, filters and other components in the pipeline; the pump outlet is connected with the sealed container, the container or is not closed but a smaller amount of the pump inlet; the air intake and the suction connection for adsorption of objects (such as precision integrated block, etc.); the pump suction end is connected with the filter container, the container port is placed for accelerating the filter, liquid filter.

2, to determine the micro pump exhaust end condition

These are discussed in the end of the micro pump suction resistance, according to these criteria have narrowed the scope of the selection, but also must consider the exhaust side resistance, so as to ultimately determine the optional range.

In practical application, the exhaust conditions facing micro vacuum pump is not the same: one is the exhaust smoothly through the atmosphere; the other is the exhaust resistance, such as in the exhaust pipe on the valve, elbow, small damping sensor, non dedicated muffler, on the surface of the liquid to gas exhaust and exhaust to closed or semi closed container etc.. In modern design and manufacture, the face of the different conditions of the vacuum pump vacuum treatment. "Exhaust port allows maximum resistance Por value" this parameter is the calibration of the pump exhaust capacity, so that we can use a rigorous technical means to determine the appropriateness of selection.

Simply, for system exhaust resistance is large, the scope of our selection is: FM series, FAA series, PCF series; system for small exhaust resistance, the selection scope is: VM series, VAA series, PK series, PC series, VCA series, VCC series, VCH series, PH series. According to the above steps, we have been able to determine the scope of the selection of micro pump. In the delineation of a number of optional series, and then based on our requirements for the flow and vacuum can determine the specific model. For poor quality products are not included in this article, try not to use. Pay attention to the choice of parameters to be left, especially the flow parameters. After the pump into the gas system, due to the pipeline, valves and other gas circuit components to cause pressure loss, will attenuate the flow, so the flow rate is less than the nominal flow rate of the pump.





Selection problems


There are some problems related to the selection of the following list, according to the use of consideration.

1, with load startup problem.

If the micro pump before starting the pumping port it has a vacuum or exhaust port already exists pressure to consider other technical parameters of the pump intake maximum starting load Pis value, the exhaust port maximum starting load Pos. Typical application examples is the use of micro pump to maintain the vacuum container or positive pressure, when the vacuum container or positive pressure below the set value, need to start the pump power is higher than the set value, stop. You can start in their own can achieve the ultimate vacuum of the products are: VM series, VAA series, PK series, PC series, VCA series, VCC series, VCH series, PH series; you can start at the maximum output pressure can reach itself under the products are: FM series, FAA series, PCF series. The performance requirements of the manufacturer's technical level is higher.

2, micro pump medium temperature problem.

According to the temperature of the gas through the pump, the choice of ordinary or high temperature.

3, the reliability of micro pump.

Depending on the severity of the consequences of the failure of the micro pump, according to their own requirements. High quality products, the average failure free running time is greater than 1000 hours, some up to thousands of hours. In particular, this parameter is determined in the running state of full load, uninterrupted under the worst conditions, if the actual usage is not full or continuous operation, the value will be higher, much as the pump working condition set. The performance is a test of the manufacturer's technical strength, can be seen from the appearance of some products, such as the use of special motor rather than ordinary low-cost motor, the volume of the case is relatively heavy weight. According to the price of the product can also get to know.

4, micro pump electromagnetic interference.

If there is a precision circuit to control the micro pump, depending on the anti-interference ability of the circuit may be required to order a small electromagnetic interference micro pump.





Application scope

Research, gas sampling, instrumentation, chemical analysis, health care, medical and health, bio engineering, automatic control, environmental protection, water treatment and other fields