Vacuum pumps: what they are, how they work and their practical applications

An industrial vacuum pump is a mechanical device designed to extract gases or liquids from the interior of containers, tubes or any system where the reduction of their interior pressure to levels less than atmospheric is required.

In Pedro Gil, we manufacture different types of vacuum pumps for industrial uses. The most commonly used are piston pumps, vane pumps, screw, diaphragm, liquid ring and lobe pumps. The general workings are similar to a compressor, although with the difference that they are designed for suction and not for the determining of the air or liquid which they are dealing with.


The workings of industrial vacuum pumps

Depending on their characteristics or applications, vacuum pumps can function in one way or another.


bomba de vacío Pedro Gil


Oil free vacuum pumps

The internal structure of the rotor, the sleeve and the moving vanes result in chambers which vary in size depending on their disposition. The pressure in the interior of the chamber increases as its dimensions decrease, given that the gas inside retains the same quantity. In the same way, the pressure diminishes when the chamber is enlarged, thus generating a vacuum.

Oil sealed vacuum pumps

They work in the same way as oil free vacuum pumps, but in this case oil is used to achieve a better seal in the chambers and, therefore, higher levels of pressure difference.


The food industry

Lyophilisation, degassing and drying: in this case the pumps are particularly indicated for the evacuation of drying chambers used for food freeze drying systems, reaching the vacuum levels required.

Concentration and solvent separation: for concentration through vacuum, the pump must offer adequate resistance to chemical substances and high tolerance to concentrates. Further, the equipment has the capacity to separate solvents out during the process.

The electrical industry

Drying and impregnation of motors, condensers, coils……: the equipment is particularly designed to operate with high voltage electrical elements, as described above. For example, moisture in coils and transformers can be evaporated to reduce the presence of humidity and other impurities.

Degassing of varnishes and resins: vacuum systems can deal with the degassing of of varnishes, resins and silicon before the initiation of the curing process leaving air bubbles trapped – including with polyurethane which is the fastest curing resin. -.

The pharmaceutical industry

Degassing and drying: both processes are fundamental during the finishing stages of pharmaceutical products. Drying is carried out after degassing. It is a process by which humidity is eliminated from a solid element with the application of external heat.

Freeze drying and packaging: freeze drying or lyophilisation, is widely used to eliminate water from biological products without causing damage to them. On packaging pharmaceutical products, a vacuum pump is used to extract air from the container. Correct packaging guarantees the safe carrying of the products such that they reach the client aseptically.

The toy industry

Metalization: vacuum plays a crucial role in many toy coating processes in which plastic, glass or metal is applied in the form of steam. In most cases, these operations would not be possible without adequate vacuum technology.

The mechanical industry

Metalization: metalization in a vacuum in the mechanical industry consists in heating (in a vacuum chamber) the coating metal, and subsequently the metal vapour condenses over the substrate. For example, vacuum metalization is used for vehicle headlights as well as to deposit aluminium on the mirrors of large telescopes.

The metallurgical industry

Impregnation of castings: vacuum impregnation is a reliable alternative since it solves the problem of porosity in cast pieces; a phenomenon which can cause, in the worst of cases, a failure in the finished piece, if the porosity has generated leakage.

Sintering: for this application, a good solution is a screw pump equipped with internal refrigeration and with a cantilever bearings design. With this equipment the accumulation of deposits is reduced thanks to moderate internal temperatures. The sintering of cutting edges serves as an example.

Desgassing: vacuum degassing systems increase the density of metals. This way, the appearance of porous zones and hard spots is avoided which is important in ensuring that the machining process is optimal.

Thermal treatments: vacuum technology is a fundamental part of the thermal treatment of metals, since it prevents adverse reactions between the elements of the metal to be treated and the environmental conditions. This ensures that the superficial properties of the material are optimized.

The optical industry

The applications of thin coatings: in the optical industry vacuum equipment is used to deposit thin active layers. From architectural glass or plastic in thin films to diamond coating: dry operation with greater efficiency.

The paper industry

Degassing and drying. during the production of sheet paper it is necessary to eliminate a high percentage of water. For better performance and drainage, a vacuum system is indispensable. Some models of these pumps include a degassing function for when there is a high gas content in the material to be pumped.

Metalization: in the production of paper-based foil, the application of certain layerings is necessary to guarantee the quality of the paper. Firstly, correct adhesion of the metal on the paper and then a print-friendly metalized layer. To achieve this, an adequate vacuum pump is indispensable.

The plastic industry

Degassing and drying: in the case of the plastic industry, the vacuum pump extracts air, adhesives and humidity from the melted plastic. Any low molecular density substance must be removed to attain quality material; that is, smooth, resistant, and with enhanced insulation properties.

Fusion, injection, molding and extrusion: liquid ring vacuum pumps are used in the production of packaging, particularly to obtain the required forms of plastic sheeting. For their part, molds which function using extrusion are automatically supplied by means of vacuum pumps.

Metalization: metalizing or coating processes are carried out to improve the surface properties of plastic, such as its hardness or resistance to corrosion. Metalization in a vacuum improves the impermeability and adhesive capacity of the material.

The chemical industry

Degassing and distilling: vacuum pumps enable the evacuation of air which has leaked into the material, while wastewater needs to be treated for environmental reasons. For this, the most efficient method is distilling in a vacuum.

Desiccation and lyophilisation: the process employed to remove water through desiccation in a vacuum at very low temperatures. As well as in the chemical industry, these processes are typical of the pharmaceutical and food industries.

Concentration and filtering: chemistry includes several processes of synthesis and concentration which require the use of vacuum technology. This is also necessary for filtering using high capacity suction pumps which increase pressure and therefore accelerate filtering.

The textile industry

Drying and degassing: during the manufacture of textiles, dirt and dust are produced which are extracted and eliminated through vacuum technology. Vacuum pumps are also fundamental for the draining and drying of textile products such as dyed rugs and carpets.