Description of the model selection of the hottest

  • Detail

Description of the selection of micro vacuum pump and micro air pump

with the vigorous development of instrument industry, micro vacuum pump and micro air pump with small volume, oil-free and environmental protection are more and more widely used. How can we choose the most appropriate product among the various micro pumps

first of all, it is necessary to clarify the purpose of the micropump. The rotating shaft head used is reminiscent of textile mills in the 19th century. We discuss it one by one in three categories

first, if you only use a micro air pump to output compressed air

simply put, it is only used to pump and inflate air, and the air extraction port of the pump is basically not used. This situation is relatively simple. It can be selected according to the output pressure from large to small: pcf5015n, faa8006, faa6003, faa4002, fm2002, fm1001. Of course, we should also refer to relevant technical parameters such as flow indicators

II. In the following cases, WKA series products should be selected

1. Use a micro pump to pump air or vacuum, but sometimes liquid water will enter the pump chamber

2. The micro pump is required to be able to pump both air and water

3. Micro pumps are mainly used to pump water, but we don't want to manually add "water diversion" before pumping. (some pumps need to manually add some "water diversion" before working, so that the pump can pump water from the low place, otherwise the pump cannot pump water or even damage.) The advantage of WKA series products is that when it does not touch water, it vacuumizes. After forming a vacuum, it uses air pressure to raise the water pressure, and then starts pumping water

4. Use a micro pump to pump water, but sometimes the pump may not have water to pump, and it is in a "dry running" state. Some traditional pumps are afraid of "dry running", which is even fatal. WKA series products are essentially a kind of composite function pump, which integrates the functions of vacuum pump and water pump. Some people call it "vacuum water pump". Therefore, when there is no water, it will vacuumize, and when there is water, it will pump water. Both the pumping state and the pumping state belong to the normal working scope, so there is no so-called "dry rotation" damage

III. The situation is slightly more complicated if the air is pumped with a micro pump

many paper-making enterprises have losses

(I). Judging the working condition of the pumping end of the micro pump

the micro pumps used for pumping are divided into two categories: gas sampling pumps and micro vacuum pumps. Although they are usually simply referred to as micro vacuum pumps without distinction, they are different from each other from a technical point of view, and special attention should be paid to the selection

in short, the gas sampling pump can only carry a small load (that is, the resistance at the pumping end cannot be too large), but the price is cheap; Strictly speaking, the micro vacuum pump can carry a large load (the exhaust end allows large resistance, or even completely blocked), but the price is slightly expensive. The specific differences between the two can be seen in the article "about the difference between micro vacuum pump and gas sampling pump", which will not be repeated

gas sampling pumps include: PM series, SA series, Sb series; Micro vacuum pumps include: VM series, VAA series, PK series, PC series, VCA series, VCC series, VCH series, FM series, FAA series, PCF series. All specifications under these series are real micro vacuum pumps, such as vm7002, vaa6005, pc3025n, etc

the resistance at the suction end of the micropump can be measured with an instrument. By comparing it with the por value of the pump's technical parameter "maximum allowable resistance at the inlet", we can know whether the model selection is appropriate. Generally, a series of rubber products are prepared by simple methods according to experience. For example, the following cases belong to large load (i.e. the resistance at the suction end of the pump is large), and can only be selected within the scope of micro vacuum pump:

① a long pipe should be connected to the suction end of the pump, or the pipe has many bending points, severe bending, or even blocking and sealing, or the inner hole of the pipe is very small (such as less than φ 2 mm)

② there are throttle valve, solenoid valve, air circuit switch, filter and other components on the pipeline

③ the pump outlet is connected with the closed container, or the container is not closed but the air intake is small

④ the pump suction port is connected with the suction cup for adsorbing objects (such as manifold blocks, precision workpieces, etc.)

⑤ the air extraction end of the pump is connected with the filter container, and a filter is placed at the mouth of the container to accelerate liquid filtration

(II). Judging the working condition of the exhaust end of the micropump

the above are all about the resistance at the exhaust end of the micropump. According to these judging conditions, the scope of model selection has been reduced, but the resistance at the exhaust end must also be considered, so that the optional range can be finally determined

in practical application, the exhaust conditions faced by the micro vacuum pump are different: one is that the exhaust is very smooth and directly connected to the atmosphere; The other is that the exhaust resistance is large, such as valves, small elbows, large damping sensors, non dedicated silencers on the exhaust pipeline, exhaust below the liquid level, gas discharge to closed or semi closed containers, etc. In modern design and manufacture, micro vacuum pumps facing different exhaust conditions are treated differently. The parameter "por value of the maximum allowable resistance at the exhaust port" is to calibrate the exhaust capacity of the pump, so that we can use strict technical means to determine whether the model selection is appropriate

in short, for systems with large exhaust resistance, our selection range is: FM series, FAA series, PCF series; For systems with low exhaust resistance, the selection range is: VM series, VAA series, PK series, PC series, VCA series, VCC series, VCH series, VBH series. According to the above steps, we can determine the selection range of micropump. Among the several optional series, the specific model can be determined according to our requirements for flow and vacuum. Products with poor quality are not listed in this article, so try not to choose them. Note that there should be allowance for parameter selection, especially flow parameters. After the pump is connected to the gas circuit system, due to the pressure loss caused by gas circuit components such as pipes and valves, the flow will be attenuated, so the flow obtained is less than the nominal flow of the pump. Some problems related to model selection are listed below, which will be considered according to the use situation

1. Start with load

if there is vacuum at the suction port or pressure at the exhaust port of the micro air pump before starting, another technical parameter of the pump should be considered: the maximum starting load PIs value at the inlet and the maximum starting load POS value at the exhaust port. A typical application example is to use a micro air pump to maintain the vacuum or positive pressure in the container. When the vacuum or positive pressure in the container is lower than the set value, the pump needs to be powered on and started, and when it is higher than the set value, it stops. The products that can be started under the extreme vacuum they can reach are: VM series, VAA series, PK series, PC series, VCA series, VCC series, VCH series, VBH series; The products that can be started under the maximum output pressure they can reach are: FM series, FAA series and PCF series whose average plastic consumption will reach more than 500kg/vehicle. This performance requires high technical level of the manufacturer

2. Medium temperature of micropump

according to the temperature of the medium gas passing through the pump, choose the ordinary type or the high-temperature type

3. Reliability of micropump

it depends on the severity of the consequences after the micro pump breaks down, completely according to your own requirements. The average trouble free continuous operation time of high-quality products is more than 1000 hours, and some are as high as thousands of hours. Pay special attention to that this parameter is measured under full load and uninterrupted operation, which is the worst working condition. If the actual use is not full load or continuous operation, the value will be higher, and the higher value depends on the working condition of the pump. This performance is entirely a test of the manufacturer's technical strength. It can be seen from the appearance of the product, such as the use of special motors instead of ordinary low-cost motors, heavy weight in the case of equivalent volume, etc. We can also know a little according to the product price

4. Electromagnetic interference of micropump

if there is a micro pump controlled by a precision circuit, it may need to order a micro pump with low electromagnetic interference depending on the anti-interference ability of the circuit. (end)

Copyright © 2011 JIN SHI