Manufacturers in every area are always looking for ways to increase their profit margins - with the goal of improving process efficiency without compromising quality or safety. This article introduces you to the dry vacuum pump technology originally used in the semiconductor industry, beginning with the vacuum transfer to industrial and laboratory processes for its clean and efficient operation.
Dry-type vacuum pumps make the working volume free of oil, thus providing a number of benefits. First, it increases pump reliability. Dry pumps are less affected by water vapor or dust particles than oil-sealed pumps, so they are more durable and require less maintenance. Reducing fuel consumption also means reducing the cost of serious oil handling. The use of a dry vacuum pump also minimizes the potential for contamination that can occur both in the oil and the pump performance - and in extreme cases such as in the final product.
The key to successfully replacing an existing oil-based vacuum pump system is to find the most suitable solution for a particular application. To see the different types of applications that can benefit, here are four different industrial processes and their main benefits of using a dry vacuum pump.
Rolling spray repair
Metal spray coating is a well-established process in the rolling coating industry that uses thermal evaporation in a vacuum environment. A thin layer of metal, most commonly aluminum, adheres to paper, polyethylene (PE) or other polymer film to form a sturdy, beautiful packaging that is moisture-proof, dust-resistant and light-isolated . This is the ideal material for food applications because it keeps the product fresh and extends its shelf life. The process is also increasingly being used to produce decorative papers, gift wrap and films.
Large rolls (up to 2 meters wide) of backing material (paper or PE film) were used in the process and they were safely placed in the winding chamber. The reels are continuously rotated - allowing the substrate material to pass through the septum into the spray booth at high speed (Figure 1). Spray room requires a very high degree of vacuum, between 10-4 to 10-5mbar, winding chamber can be maintained at a lower vacuum, about 10-2mbar. Spraying is the result of a thermal evaporation process in which the metal is heated so that it is vaporized and then deposited on the substrate material.
The vacuum pumping system used in roll-on applications consists of several steam booster / diffusion pumps as well as one or more stages of mechanical booster in addition to the foreline pump (Figure 1). Forepumps must meet system throughput and foreline pressure requirements at all times - so the most important point is that they are reliable and easy to maintain. This will minimize the loss of production time, the loss of production time will affect the productivity of equipment.
Among many advanced roll coating companies, dry pumping technology has become an increasingly attractive antegrade pump replacement and has been used to replace the traditional oil seal system. Dry-type pumps are inherently a type of clean device that is less susceptible to the accumulation of dust or other particulates that often appear in the seal liquid of a wet pump, resulting in a reduced quality spray. Dry pumps do not experience any reduction in performance between runs, thus ensuring repeatability during roll coating.
The lack of oil in the pump also brings other environmental and maintenance benefits. For example, the oil used in wet pumps is often exposed to the process gas and the gas is pumped into the spray booth. As a result, the oil can be contaminated with particulates during processing. A long time, the oil will be bad, so need regular, frequent replacement of oil.
It must also be taken into account that the gas is being used. For example, if oxygen is used to generate alumina, detonating air is formed when oxygen is mixed with the hydrocarbon oil. Dry pumps are capable of pumping any concentration of oxygen safely, so using a dry pump as a replacement means that companies do not have to install rigorous process control equipment that can be quite expensive
Effective treatment of water vapor
Dry pump technology is currently being used in metallurgy and heat treatment applications. Recently, some of the world's largest dry-type pump systems have been installed for large-scale steelmaking exhaust. Smaller systems are used to process refined and ultra-heat-resistant stainless steel.
For example, vacuum induction melting (VIM) is a metallurgical process that was originally developed to handle special alloys and is increasingly being used to produce other materials such as stainless steel. Typical applications using VIM include casting parts for aircraft engines and refining high-purity metals and alloys.
The process uses electromagnetic induction to melt the metal under vacuum. This induces eddy currents in the metal - the inductive source is an induction coil with an alternating current. Eddy currents heat and melt the load.
Metallurgical processes like this produce a quantity of condensable water vapor, which contains water vapor. Oil-sealed rotary piston pumps were once the most common type of pump used in these processes, but with this pump, the water vapor mixes with the lubricant, causing the lubricant to age and increasing the pumping mechanism The degree of wear. Dry pumps will not be affected by water vapor like this because they work at higher temperatures and have no oil in the process chamber.
Reduce maintenance costs
Vacuum is also used in brake gas stations, which are part of the car's production line. Carmakers wanted assembly time as fast as they could, and they developed a way to evacuate and fill the brake circuits with vacuum pumps and to leak test the brake circuits - and as a result, they are now able to switch off at 60 seconds Complete the whole process.
A car manufacturer recently replaced the original three oil-sealed vacuum pumps with three BOC Edwards Drystar pumps; one for each brake circuit and one for a backup pump. The main reason for this is that oil-sealed pumps need to be maintained to keep them operating at their maximum capacity. Unlike the oil-sealed pumps that are replaced, dry pumps now being installed need only be overhauled every 6 years. Dry-type vacuum pump system is also more cost-effective, as the consumables needed are also reduced. Many pumps, such as the GV series from BOC Edwards, have the same safety features as standard pumps, such as swift closing of the temperature switch, which protects the pump if thermal issues associated with the process occur.
Minimize the risk of contamination
A mass spectrometer manufacturer recently incorporated a dry pump into its mass spectrometer range of interest. Mass spectrometers are used to measure and analyze molecules that are necessary for research and development tools in industry and academia. They separate the ions according to the different masses and charges of the gas ions to determine the chemical composition of the material. To do this, it must be ensured that when ions are generated (this occurs in the ionization chamber at the beginning of the process) they are free to travel through the machine without hitting the air molecules - thus creating a vacuum to ensure There is no air in the room. So that the working volume of the vacuum pump does not contain oil but also ensures that no oil molecules exist.
Most users are pharmaceutical companies that require equipment for bioanalysis and drug identification for clinical trials. Dry-vacuum pump solutions better ensure high-precision measurements that are essential for some organizations that must meet the regulatory requirements set by the U.S. Food and Drug Administration (FDA) and other national authorities . By using a dry vacuum pump, the danger of contamination is eliminated.
Summary: Dry pumps have been successfully used in the semiconductor manufacturing industry for many years and become more and more common in many industries. The examples above show that dry pumps are more fully prepared to meet the challenge of more and more industrial applications where traditional oil seal technology has dominated.
The reason for their increasing use is clear because they are reliable, wear-resistant and easy to maintain, with significant benefits for the results. In the rolling coating industry, for example, an oil-sealed vacuum pump used in this environment costs about 40% of the cost of a new pump each year.
Dry pumps make normal working hours longer, and because of their repeatability, they result in higher production yields and cost savings. This technology is not only secure, it is designed to work flawlessly even in harsh work environments. Dry pumps have a good return on investment and are expected to pay off in 12 to 18 months - assuming no need to cut investment to improve processing.