How to Choose a Laboratory Oil-Free Vacuum Pump and Its Use Notes

Definition of laboratory vacuum pump

Micro vacuum pump or micro gas pump is often called a laboratory vacuum pump, because, in scientific research and laboratories, it is often used for gas circulation, gas sampling, suction filtration, vacuum indirect water pumping, etc.

Detailed introduction and examples

Laboratory vacuum pumps, namely miniature vacuum pumps, are generally powered by DC motors. Because the DC motor can be small in size, light in weight, and easy to carry, DC is also a safe voltage. There are two types of Hawach vacuum pumps: standard diaphragm vacuum pumps and anti-corrosion diaphragm vacuum pumps.

SLVPGM100A-T-Anti-Corrosion-Diaphragm-Vaccum-Pumps SLVPGM050B-T-Anti-Corrosion Diaphragm Vacuum-Pump SLVPGM033A-Standard-Diaphragm-Vaccum-Pumps (1)

When the laboratory vacuum pump is used for gas circulation, it is necessary to make the gas in the two containers flow evenly, which requires the pumping port to withstand a certain resistance. In front of the suction port of the pump, a closed container is generally arranged. In addition, a lot of gas circuit components, such as valves, flow meters, and closed containers, are also connected to the exhaust end of the pump. The exhaust port is completely blocked.

The vacuum pumps commonly used in laboratories, its suction port can provide negative pressure of -730mmHg. The suction port and exhaust port of this kind of miniature vacuum pump can be blocked arbitrarily (hung heavy load), and even the suction port and the gas port are completely blocked, which is also a normal operation. So if used for gas circulation, sampling, pumping, and pumping dual-purpose pump is very suitable.

The advantage of the general vacuum pump is that it hangs the load at the suction port, and the exhaust cannot be blocked. This is taboo in the application of the experimental process.

In the test, sometimes the pumped liquid is very corrosive and cannot allow the liquid to enter the air pump. It is also necessary to use a miniature vacuum pump for indirect water pumping, which is another advantage of the laboratory vacuum pump.

The function of the vacuum pump is to suck out the gas from the vacuum chamber to make the gas pressure in the vacuum chamber reach the required vacuum degree. Due to the wide range of functions of the vacuum pump, it can be used in conjunction with other instruments. Such as vacuum filtration, microbial detection, waste liquid extraction, rotary evaporator, vacuum drying oven, freeze dryer, extraction device, concentration, and other equipment.

Classifications of laboratory vacuum pumps

Laboratory vacuum pumps can generally be divided into dry vacuum pumps and non-dry vacuum pumps. Dry vacuum pumps are also called oil-free vacuum pumps, which are characterized by relying on the components of the machine to achieve the required vacuum degree and are pollution-free and maintenance-free. The most commonly used in laboratories are the oil-free piston type (mostly used in microbiological laboratories) and the corrosion-resistant diaphragm type (mostly used in chemical laboratories).

For the non-dry vacuum pumps, it requires to consider using water or oil, or other similar substances to get the ideal vacuum. The most used in the laboratory is the oil-type rotary vane pump, which is generally used in conjunction with freeze dryers, vacuum drying boxes, etc.

Because its structure is different from traditional oil pumps or water pumps, oil-free vacuum pumps do not need to rely on other media and only need to be plugged into the power supply. At present, the application in the laboratory has become more and more extensive. The most common uses of laboratory oil-free vacuum pumps include filter bottle set or filter equipment for suction filtration; connection of vacuum drying box with rotary evaporator; distillation flask or reaction kettle for reduced pressure distillation; with a pipette bottle and pipette tip for cell culture waste liquid and other residual liquid after the experiment.

In these applications, the laboratory oil-free vacuum pump does not require pumping oil or water supply and has obvious advantages and inconveniences. Whether there is any pollution during use, the vacuum degree and pumping speed can also meet the needs of the above-mentioned purposes. HAWACH oil-free vacuum pump uses better raw materials to manufacture pump parts, which lengthens the service life; all moving parts are durable, with high-quality brushless motors to increase pump life.

SLVPGM100A-T-Anti-Corrosion-Diaphragm-Vaccum-Pumps SLVPGM033A-Standard-Diaphragm-Vaccum-Pumps (1)

Factors to be considered when purchasing an oil-free vacuum pump

For the choice of the vacuum pump, here are several matters to be noted. First of all, we must understand the purpose of the vacuum pump and whether the extracted gas is corrosive. For reagent purification, you need to choose a corrosion-resistant vacuum pump; secondly, the vacuum pump components should be considered. If it is used to configure a rotary evaporator, a corrosion-resistant vacuum pump must be used. The vaporized gas is corrosive; if it is used in a drying oven, a vacuum pump with a higher vacuum can be selected, such as an oil pump in a non-dry vacuum pump.

The use of an oil-free vacuum pump can ensure that the vacuum required by the drying box can be reached in a short time, and there is no need to add pump oil or connect the water source, and it is maintenance-free and pollution-free. When purchasing an oil-free vacuum pump, users should consider the characteristics of each different application to choose a suitable model. For example, the vacuum drying box should be equipped with a laboratory oil-free vacuum pump with a high vacuum degree. The degree of vacuum will directly affect the amount of air extracted and the drying effect. At the same time, the size of the cabinet needs to be considered. For example, a 050B laboratory vacuum pump can be used for a vacuum oven below 50L, with a pumping speed of 30L/Min, which fully meets the suction requirements of such a large cabinet.

Three different occasions should be considered if vacuum filtration is required. If the sample to be filtered is highly corrosive and volatile gases, such as hydrofluoric acid, and is also generated during the filtering process, corrosion-resistant and oil-free diaphragm vacuum pumps are required. The parts of the anti-corrosion pump in contact with gas are treated with Teflon surface treatment, which has complete resistance to chemical corrosion.

If you pump ordinary solutions, such as mobile phase filtration, microbial filtration, suspended matter filtration, and reagent buffer sterilization and impurity filtration, the basic model can be fully satisfied, with an oil-free design, and the buffer cup can prevent back suction.

If the sample is to be filtered with very high particulate or solid content or is very viscous, you need to use a model with a higher vacuum degree, which can generate a stronger force to pull the filtrate through the filter membrane.

Use notes of laboratory oil-free vacuum pump

The following items should be paid attention to when using the laboratory oil-free vacuum pump:
1. If a small amount of organic gas is inhaled during the operation of the vacuum pump, in order to prevent the organic gas condensate from corroding the internal components, the air should be evacuated for at least 0.5-1h.
2. It is forbidden to directly suck liquid into the vacuum pump. If a small amount of liquid is sucked in during the working process of the vacuum pump, the vacuum pump should not be shut down immediately after use, and the air should be pumped for at least 0.5-1h to empty.
3. The vacuum pump is not suitable for pumping hot gas. If you really need to pump high-temperature gas for a long time, it is recommended to add a cold trap in front of the vacuum pump to reduce the temperature of the gas pumped into the vacuum pump.
4. Maintain good ventilation to facilitate heat dissipation and prolong life.
5. When used in a vacuum drying oven, please pay attention to open the vacuum valve of the vacuum drying oven, start the vacuum pump to vacuum the drying oven, and then start the vacuum drying oven to heat up after reaching the required vacuum.
6. When used in the suction filter device or waste liquid suction, please pay attention: timely dump the liquid in the liquid collection bottle, and the liquid directly into the vacuum pump can easily cause damage to the vacuum pump. Do not immediately turn off the vacuum pump, when a small amount of liquid is pumped accidentally during use. It is recommended to immediately unplug the pump tube connected to the vacuum pump to allow the vacuum pump to pump air for at least 0.5-1h for evacuation; if a large amount of liquid is accidentally pumped into the vacuum pump, it needs to be repaired in time.