How to choose a micro vacuum pump Small vacuum pump?

It depends on what you're doing for it.

The ultimate pressure of the vacuum pump should meet the working pressure of the process. Pumps are usually selected for ultimate pressures that are about an order of magnitude lower than the process requirements.

Each pump has a certain operating pressure range, so the pump's operating point should be within this range and should not be allowed to work for a long time beyond the allowable working pressure.

When you choose an oil-sealed pump, you should first find out if your vacuum system has requirements for oil contamination. If the equipment strictly requires oil-free, you should choose a variety of oil-free pumps, such as: water ring pumps, cryogenic pumps, etc.

If the requirements are not strict, you can choose to have an oil pump, plus some anti-oil pollution measures, such as cooling traps, oil traps, baffles, etc., can also meet the requirements of clean vacuum.

Understand the composition of the pumped gas, whether the gas contains condensable vapor, whether there is particle dust, whether it is corrosive, etc. When choosing a vacuum pump, you need to know the gas composition and select the appropriate pump for the gas being pumped. If the gas contains vapors, particles, and corrosive gases, it should be considered to install auxiliary equipment such as condensers, dust collectors, etc. on the inlet lines of the pump bureau.

When choosing an oil-sealed vacuum pump, the company should consider the impact of the oil vapor (fume) discharged from the vacuum pump on the environment. If the environment does not allow pollution, you should choose an oil-free vacuum pump, or exhaust the oil vapor to the outside.

1. Definition of vacuum pump:

Vacuum pump refers to a device or equipment that uses mechanical, physical, chemical or physicochemical methods to pump air from the pumped container to obtain vacuum. In layman's terms, a vacuum pump is a device that uses various methods to improve, generate and maintain vacuum in an enclosed space.

According to the working principle of vacuum pumps, vacuum pumps can basically be divided into two types, namely gas capture pumps and gas transfer pumps. It is widely used in metallurgy, chemical industry, food, electronic coating and other industries.

Second, the selection of vacuum pumps:

1. First of all, you should fully understand the composition of the pumped gas. If the gas contains no condensable vapor, no particle dust, no corrosiveness, etc.; If the gas contains vapors, particles, and corrosive gases, auxiliary equipment, such as condensers, dust collectors, etc., should be considered on the inlet pipeline of the pump; If the extracted gas is still corrosive, the material must be selected; If the pumped gas is the most efficient, the water ring vacuum pump should be selected and equipped with an explosion-proof motor, because the whole working process of the water ring vacuum pump is isothermal.

2. What is the impact of the oil vapor discharged by the vacuum pump on the environment, if the environment does not allow pollution, you can choose an oil-free vacuum pump such as a water ring vacuum pump, or discharge the oil vapor to the outdoors.

3. The requirements of vacuum equipment or parts for oil pollution, if the equipment is strictly required to be oil-free, various oil-free pumps should be selected, such as: water ring vacuum pump, molecular sieve adsorption pump, sputtering ion pump, cryogenic pump, etc., if the requirements are not strict, you can choose to have an oil pump, and add some anti-oil pollution measures, such as cold traps, baffles, oil traps, etc., can also meet the requirements of clean vacuum.

4. If there are multiple large water ring vacuum pumps working at the same time, the circulating liquid should be cooled, otherwise the vacuum degree will be affected, and the cooling device can be equipped with a cooling tower, and a booster pump must be equipped to pressurize the pipeline.

5. Whether the vibration generated by the vacuum pump during work has any impact on the process and the environment, if the environment does not allow, the pump without vibration should be selected or shock absorption measures should be taken.

6. The working pressure of the vacuum pump should meet the requirements of the ultimate vacuum and working pressure of the vacuum equipment, and the vacuum degree of the vacuum pump is usually half to an order of magnitude higher than the vacuum degree of the vacuum equipment.

7. Under its working pressure, the vacuum pump should be able to discharge all the gas generated during the process of the vacuum equipment.

1. The tightness of the vacuum pump oil.

The vacuum pump oil demand has a suitable viscosity, which can make the vacuum pump start quickly at low temperature, and the vacuum pump oil can have good sealing at high temperature, and the vacuum pump oil has a low temperature rise in the pump. It does not contain light volatile components, which reduces the oil return rate of the vacuum pump during application.

2. The saturated vapor pressure of the oil of the vacuum pump manufacturer.

Saturated vapor pressure is one of the key indicators of vacuum pump oil. In a closed container at a constant temperature, the pressure when the vapor-liquid phase reaches dynamic equilibrium is called saturated vapor pressure.

The saturated vapor pressure of the oil should be as low as possible, and at the maximum operating temperature of the pump, it should still have a sufficiently low saturated vapor pressure and be lower than the limiting pressure of the vacuum pump rules. At least kPa must be reached at 60 temperatures (because for every 20 temperature rises, the saturated vapor pressure is about **an order of magnitude).

3. The ultimate full pressure and the ultimate partial pressure of the vacuum pump oil.

Ultimate Total Pressure: The sum of the pressures produced by all substances (gases) of the vacuum pump measured by a Pirani meter or a thermocouple vacuum gauge. At present, foreign countries pay attention to the test index of full pressure.

Limit partial pressure: The ultimate air partial pressure of the pump measured by a mercury compact vacuum gauge (McMax meter), the partial pressure of the two-stage rotary vane pump should be 6 10-5 kPa. The difference between the ultimate full pressure and the limit partial pressure is requested to be no more than an order of magnitude.

The greater the difference between the two, the more volatile components are contained in the vacuum pump oil, and the worse the properties of the oil.

4. The smoothness of the vacuum pump oil.

Friction wear on the friction surface, fatigue on the surface, and corrosion wear are all related to smooth conditions. A high-performance vacuum pump oil is good for inhibiting corrosion and wear; It can effectively reduce adhesive wear and appearance fatigue wear; Fluid smoothing agents have a cleaning effect on the friction surface and can also reduce friction wear. Reduces frictional resistance to save energy and reduce wear to extend mechanical life.

5. Cooling performance of vacuum pump oil.

Reducing the temperature of the friction surface is an important effect of smoothing. When the friction surface moves, it is necessary to restrain the friction force and do the work, and all the work expended in restraining the friction force is converted into heat, and the result will cause the temperature of the friction surface to rise. The magnitude of the frictional heat is related to the smooth state, with the heat of high viscosity being the largest, the heat of low viscosity being the smallest, and the heat of border friction being somewhere in between.

It can be seen that the use of vacuum pump oil with suitable viscosity can not only complete the smooth liquid and reduce the generation of frictional heat, but also bring the frictional heat out of the pump in time.

6. The cleanliness of vacuum pump oil.

The friction pair is inevitably in contact with the surrounding medium, causing corrosion, rust and destruction. Excellent vacuum pump oil requires that the friction area be cleaned and cleaned as much as possible; Resist corrosion, rust and maintain the friction surface from oil metamorphosis or external corrosion.

What are the specific contents of the performance parameters and scope of use of the vacuum pump, the following Zhongda Consulting will answer for you.

First, the performance parameters of the vacuum pump.

1. The ultimate pressure of the vacuum pump.

The ultimate pressure unit of the pump is PA, which refers to the minimum pressure at which the pump is equipped with a standard test hood at the inlet and works under the specified conditions, and tends to be stable under the condition that no gas is introduced.

2. The pumping rate of the vacuum pump.

The pumping rate of the pump is in m3 s or l s, which refers to the ratio of the gas flow rate flowing from the test hood to the equilibrium pressure measured at the specified position of the test hood when the pump is equipped with a standard test hood and works under specified conditions. Abbreviated as the pumping speed of the pump.

3. The pumping capacity of the vacuum pump.

The pumping capacity of a vacuum pump is measured in pa m3 s or pa l sRefers to the flow rate of gas at the inlet of the pump.

4. The starting pressure of the vacuum pump.

The starting pressure unit of the vacuum pump is PA, which refers to the pressure when the pump starts without damage and has the effect of pumping.

5. The pre-pressure of the pump.

The unit of pre-pressure of a vacuum pump is PA, which refers to the outlet pressure of a vacuum pump with an exhaust pressure lower than one atmosphere.

6. The maximum pre-pressure of the vacuum pump.

The maximum backing pressure unit at the vacuum pump port is PA, which refers to exceeding the backing pressure that can damage the pump.

7. The maximum working pressure of the vacuum pump.

The maximum operating pressure unit of a vacuum pump is PA, which refers to the inlet pressure corresponding to the maximum pumping capacity. At this pressure, the pump can operate continuously without deterioration or damage.

8. Compression ratio.

The compression ratio is the ratio of the outlet pressure of the pump to the inlet pressure of a given gas.

9. Ho's coefficient.

The ratio of the actual pumping velocity over the area of the pump's pumping channel to the theoretical pumping velocity calculated at that location based on molecular flow.

10. Pumping speed coefficient.

The ratio of the actual pumping speed of the pump to the theoretical pumping speed calculated at the pump inlet based on molecular epsom flow.

11. Reflux rate.

The unit of reflux rate of the pump is g cs.It refers to the mass flow rate of the pump flow per unit area through the pump inlet when the pump is working under specified conditions.

12. Allowable amount of water vapor.

The allowable unit of water vapor is kg h, which refers to the mass flow rate of water vapor that can be pumped out by the gas ballast pump under normal environmental conditions during continuous operation.

13. The maximum allowable water vapor inlet pressure.

The maximum permissible water vapor inlet pressure unit is PaIt refers to the highest inlet pressure of water vapor that can be removed by the gas ballast pump during continuous operation under normal environmental conditions.

Second, the scope of use of vacuum pumps.

Since the operating pressure range and starting pressure of various vacuum pumps are different, these requirements must be met when selecting vacuum pumps. Table 3-1 shows the working pressure range and the starting pressure value of various commonly used vacuum pumps for reference.

(1) Pumping rate: The pumping rate of the vacuum pump is also called the production capacity, at a certain temperature, the vacuum pump can pump the volume of gas from the equipment in a unit time, the unit m 3 s or mvh is expressed.

2) Residual pressure: also called ultimate vacuum, that is, the vacuum pump can reach the lowest pressure in a steady state, the unit "toir" or expression. ltorr = l / 760 atm =。

3) Pumping capacity: At a certain temperature, the vacuum pump can pump out the specified amount of gas from the equipment in a unit time, which is called pumping volume, unit m h.

4) Starting pressure: the pressure when the vacuum pump starts to work.

(1) Pumping rate: The pumping rate of the vacuum pump is also called the production capacity, at a certain temperature, the vacuum pump can pump the volume of gas from the equipment in a unit time, the unit m3 s or m3 h is indicated.

2) Residual pressure: also called ultimate vacuum, that is, the lowest pressure that the vacuum pump can reach in a steady state, expressed in "torr" or %. 1torr=1/760atm=。

3) Pumping volume: At a certain temperature, the vacuum pump can pump out the specified amount of gas from the equipment in a unit time, which is called pumping volume, unit m3 h.

4) Starting pressure: the pressure when the vacuum pump starts to work.

The main ones are: pumping speed, ultimate vacuum, installation size of the suction port, installation size of the exhaust port, and other parameters can be further consulted.

This depends on the brand and type, power model, etc., whether it is oily or oil-free, and there is a big difference. The main parameters are: 1

vacuum; 2.exhaust pressure; 3.Exhaust volume; 4.

Piping connection bore diameter; 5.Noises; 6.Power; 7.

Single-phase or three-phase electricity.