Micro vacuum pump selection skills
In recent years, with the further requirements of various industries, such as miniaturization, portability, and non-contamination of working media, vacuum compact, oil-free maintenance-free, low-noise, portable, DC-powered micro vacuum pumps and micro air pumps have been obtained. More and more widely used.
However, due to the wide variety of micro vacuum pumps and micro air pumps, for example, it can be divided into: micro vacuum pump, brushless micro vacuum pump, micro air pump, brushless micro air pump, micro sampling pump, micro pump, micro pump, micro cycle pump, micro Negative pressure vacuum pumps, etc.; causing customers to often be confused, how to choose the most suitable products for their own conditions from so many micro vacuum pumps?
[General Principles for Micro Vacuum Pump and Micro Air Pump Selection]:
Brushless can be used without brush, brushless products can not be used without brushing parameters.
In fact, it can be clearly distinguished from the types and uses of micro vacuum pumps:
1. Classification of micro vacuum pumps and micro air pumps
According to whether the micro vacuum pump integrates "brushed motor" or "brushless motor".
Because the current micro vacuum pump and micro air pump (hereinafter referred to as micro vacuum pump) are generally electric, that is, the motor and the pump body are integrated, and the pump is operated by DC power supply. Therefore, it can be divided into the types of motors: brushed micro vacuum pumps and brushless micro vacuum pumps.
[Characteristics of brushed micro vacuum pump]
Advantages: The brush motor is powered by a large torque, so the negative pressure and flow rate can be made relatively high. The domestic high-end brush motor is relatively mature. The domestic top-ranking production of high-end micro vacuum pump manufacturers, the quality of such brush products. Performance and reliability are better. And the overall cost is cheaper than the micro vacuum pump with high-grade brushless motor;
Disadvantages: the life of brushed micro vacuum pump is shorter than the life of high-grade brushless
[Characteristics of Brushless Micro Vacuum Pump]
Advantages: long life, especially the use of high-grade brushless motor, the life is often close to tens of thousands of hours (full load); especially suitable for continuous operation around the clock, such as long-term online sampling pump; some can even continue Run for more than 1 year, if it is used intermittently, it may even be several years. Moreover, there is also a “speed control†function, that is, the speed of the duty cycle motor can be used (PWM speed regulation), so as to achieve the purpose of indirect pump flow, with the corresponding control circuit, even constant voltage, constant current, constant speed can be realized. And other advanced applications.
Disadvantages: Negative pressure, positive pressure, flow and other parameters are smaller than brushed; cost is higher than brushed.
Therefore, in the case where the parameters can be achieved, the brushless micro vacuum pump should be selected as much as possible.
Second, the use of micro vacuum pumps, micro air pumps
According to the use of the micro pump, the type is selected. We discuss them one by one in three major categories.
(1) If only the compressed air is output by a micro air pump.
Simply put, it is only used to pump and inflate, the pump's pumping port is basically not used, common applications: aeration under the page, airing in a closed container, etc.; this situation is relatively simple, the optional model is as follows (positive pressure is large To small order):
1.PCF5015N: brush, positive pressure: 100KPa, maximum flow: 15L/Min;
2.FAC series: brush, positive pressure: 40-85 KPa, maximum flow: 2-5L/Min; is an upgrade of FAA series, please give priority;
3.FAA series: brush, positive pressure: 40-80 KPa, maximum flow: 2-6L/Min; (may be eliminated later)
4.FAY series: brushless, positive pressure: 40-60 KPa, maximum flow: 2-3L/Min;
5.FML series: brushless, positive pressure: 10-20 KPa, maximum flow: 0.8-1.5L/Min;
6.FM series: brush, positive pressure: 10-20 KPa, maximum flow: 1-2L/Min (may be eliminated later)
Of course, it is also necessary to refer to relevant technical parameters such as flow indicators.
(b) If the pump is pumped with a micro pump, the situation is slightly more complicated.
1. Judging the pumping end condition of the micro pump
There are two types of micro air pumps for pumping: gas sampling pumps and micro vacuum pumps. Although they are often simply referred to as micro vacuum pumps indiscriminately, there are differences 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 (ie: the suction resistance of the pump can not be too large), but the price is cheap; in the strict sense, the micro vacuum pump can carry a large load (the suction end allows large resistance, or even complete Blocked), but the price is slightly more expensive. The specific differences between the two can be found in the article "About the difference between micro vacuum pump and gas sampling pump", no longer repeat.
Gas sampling pumps are: PM series, SA series, SB series;
The micro vacuum pump is divided into two categories: single pumping, pumping and pumping.
Single pumping categories include (from small to large flow, negative to low):
(1). Small flow small volume VM series: brush, maximum flow: 1-5L/Min; negative pressure: -20~-40KPa; will be eliminated;
(2). Small flow small volume VMC series: brush, maximum flow: 1-5L/Min; negative pressure: -20~-40KPa; is VM series upgrade product, please choose first;
(3). Small flow small volume VML series: brushless, maximum flow: 0.8-1.5L/Min; negative pressure: -10~-20KPa;
(4). Medium flow VLC series: brushless, maximum flow: 1-3L/Min; negative pressure: -16~-35KPa;
(5). Medium flow VLK series: brushless, maximum flow: 4-6L/Min; negative pressure: -45~-55KPa;
(6). Medium flow PK series: brush, maximum flow: 8-12L/Min; negative pressure: -50~-55KPa;
(7). Negative pressure PC series in large flow: brush, maximum flow: 20-25L/Min; negative pressure: -60~-70KPa;
(8). Maximum flow VCA series: brush, maximum flow: 38L/Min; negative pressure: -50KPa;
(9). High negative pressure and small flow VBH series: brush, maximum flow: 6L/Min; negative pressure: -80KPa;
(10). High negative pressure and large flow VCH series: brush, maximum flow: 28L/Min; negative pressure: -90KPa;
Pumping and pumping dual-use categories include (from small to large flow, negative to low):
(1). Small flow, small volume, low positive pressure FM series: brush, maximum flow: 1-2L/Min; negative pressure: -10~-20KPa; positive pressure: 10~20KPa;
(2). Small flow small volume low positive pressure FML series: brushless, maximum flow: 0.8-1.5L/Min; positive pressure: 10~20KPa; negative pressure: -10~-20KPa;
(3). Medium flow FAY series: no brush, maximum flow: 2-3L/Min; positive pressure: 40~60KPa; negative pressure: -30~-35KPa;
(4). Medium flow medium pressure FAY series: brushless, maximum flow: 2-3L/Min; positive pressure: 40~60KPa; negative pressure: -30~-35KPa;
(5). Medium flow medium pressure FAC series: brush, maximum flow: 2-5L/Min; positive pressure: 40~85KPa; negative pressure: -30~-45KPa;
(6). High flow and high positive pressure PCF series: brush, maximum flow: 15L/Min; positive pressure: 100KPa; negative pressure: -50KPa;
All specifications under these series are true miniature vacuum pumps such as VMC7002 and VLC8401.
The magnitude of the suction resistance of the micropump can be measured by the instrument, and it can be compared with the pump's technical parameter "maximum resistance of the inlet port" Por value to know whether the selection is appropriate. Usually, it is determined by simple method based on experience. For example, the following conditions are all large loads (ie, the pump has a large suction end resistance), and can only be selected within the range of the micro vacuum pump:
1 The pump should be connected to a long pipe at the pumping end, or the pipe has many bending points, strong bending or even blocking, or the pipe hole is small (for example, less than φ2 mm);
2 There are throttle valves, solenoid valves, pneumatic switches, filters and other components on the pipeline;
3 pump suction port is connected with the closed container, or the container is not sealed but the intake air amount is small;
4 pump suction port is connected with the suction cup for adsorbing objects (such as integrated blocks, precision workpieces, etc.);
The pumping end of the 5 pump is connected to the filter container, and a filter screen is placed at the container mouth to accelerate the liquid filtration.
(2) Judging the working condition of the micro pump exhaust end
All of the above are discussing the problem of the resistance of the pumping end of the micropump. According to these judgment conditions, the range of the selection has been reduced, but the problem of the resistance of the exhaust end must also be considered, so that the optional range can be finally determined. In practical applications, the micro-vacuum pump faces different exhaust conditions: one is that the exhaust is smooth and straight to the atmosphere; the other is that the exhaust resistance is large, such as valves on the exhaust line, small bends Large damping sensor, non-dedicated silencer, exhaust below the liquid level, gas discharge to a closed or semi-closed container. In modern design and manufacturing, micro vacuum pumps facing different exhaust conditions are treated differently. The parameter “Exhaust port allows maximum resistance Por value†is to calibrate the pump's exhaust capacity, so that we can use strict technical means to determine whether the selection is appropriate.
Simply put, for systems with high exhaust resistance, our selection range is: FML series, FAC series, FAY series, PCF series; for systems with low exhaust resistance, the selection range is: VMC series, VML series, VLC series, VLK series, PK series, PC series, VCA series, VCC series, VCH series, VBH series. Based on the above steps, we have been able to determine the selection range of the micropump. In the selected series, we can determine the specific model according to our requirements for flow and vacuum. For products of poor quality, this article is not included in this article, try not to use it. Note that the parameter selection should leave a margin, especially the flow parameters. After the pump is connected to the pneumatic system, the pressure loss will be attenuated due to the pressure loss of the gas circuit components such as pipes and valves. Therefore, the flow rate obtained is less than the nominal flow rate of the pump. Some problems related to the selection are listed below, depending on the usage. consider.
1, with load startup problems.
If the micropump has a vacuum at the pumping port before starting or if there is already pressure in the exhaust port, consider another technical parameter of the pump: the maximum starting load Pis value of the inlet and the maximum starting load Pos value of the exhaust port. A typical application example is to use a micro air pump to maintain the vacuum or positive pressure state inside the container. When the vacuum or positive pressure in the container is lower than the set value, the pump needs to be energized to start, and the machine is stopped when it is higher than the set value. This performance requires a high level of technical skill from the manufacturer. If you need this performance, it is best to contact the manufacturer for confirmation.
2. The medium temperature problem of the micro pump.
According to the temperature of the medium gas passing through the pump, it is necessary to select a normal type (temperature range: 0-50 ° C) or a high temperature type (temperature range: 0-100 ° C).
3. The reliability of the micro pump.
Depending on the severity of the consequences of the micropump failure, it is completely up to your requirements. The average trouble-free continuous running time of quality products is more than 1000 hours, and some are as high as thousands of hours. In particular, this parameter is measured under full load and uninterrupted operation. It is the worst case. If the actual use is not full load or continuous operation, the value will be higher and the height will be higher depending on the working condition of the pump. set. This performance is a test of the manufacturer's technical strength, from the appearance of the product can be seen, such as the use of special motors rather than ordinary low-cost motors, the weight is relatively heavy, and so on. According to the price of the product, you can also know one or two.
4. The electromagnetic interference problem of the micro pump.
If you have a precision circuit-controlled micropump, depending on the circuit's immunity to interference, you may need to order a micropump with low electromagnetic interference. The best solution is to choose a micro pump (speed governor) with a brushless motor; because the brushless micro air pump has basically no interference, the low interference performance even exceeds the low interference model customized by the brush micro air pump; and the price is the same as the same parameter. Please note that there may be lower custom-made products.
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