Fore vacuum pumps are defined as those which exhaust to atmospheric pressure. They are also required to support secondary pumps or to attain the initial conditions for their operation. There are two types of fore vacuum pumps:
In this blog post, we'll examine the key working principles of common multi-stage roots fore vacuum pumps
Multistage roots pumps are dry vacuum pumps used in low, medium, high and ultra-high vacuum systems to produce “dry” conditions.
The simple (single-stage) roots pump is most commonly employed as a booster pump for use in combination with several types of fore pumps (such as rotary vane pumps, screw and liquid ring pumps) to improve (or ‘boost’) ultimate pressure and pumping speeds. When multistage roots pumps are employed, no fore pump is required and they can operate from atmospheric pressure. A multi-stage roots pump can consist of up to eight stages and employ several sets of rotors (on a shared shaft). Roots pumps are suitable where a dry and clean atmosphere is important or, more likely, essential. Consequently, they are frequently used in the manufacture of semiconductors and solar panels, as well as for coatings, other industrial applications and for scientific instruments and research.
In its simplest form, roots pumps employ two counter-rotating interconnected ‘lobed’ rotor units rotating within a stator housing or casing. Gas enters through an inlet flange located perpendicular to the rotating units and is then “isolated” between the rapidly rotating rotors (which are spinning in opposite directions) and the stator. The compressed gas is then expelled via the exhaust port.
Building upon this simplistic model of a roots pump, a multi-stage roots pump (which can consist of up to eight stages) employs several sets of rotors (on a shared shaft). The geometry of the rotors creates compression and hence each stage produces a progressively higher pressure. In this way, the product of a lower stage is the “feed gas” for the next higher stage (but without any interconnecting valves).
As with single-stage (i.e. roots blower) pumps, in multistage units there is no contact between rotors and the stator housing — the units are hermetically sealed, they are robust and they can operate for long periods between service. Additionally, the new generation of multistage roots pumps have been specifically designed to be used in quiet and clean environments, such as in analytical instruments and research laboratories where — operating with pumping speeds of 25 to 200 m3/h — they create a very low noise of up to 52 dB(A).
The performance characteristics of roots pumps vary depending on a number of factors, including the number of stages, the unit size, rotation, speed of operation, ambient temperature, initial inlet pressure and the characteristics of the gases being pumped.
The following listings provide some of the more obvious and significant performance characteristics:
Multistage roots pumps are predominantly employed where their dry, clean and high pumping speed characteristics can be used to the best advantage. As a result their applications include: analytical instruments, R&D and space, the semiconductor and solar industries, and the laser industry. They’re also used in furnaces, metallurgy and a variety of coatings applications (where their very dry nature is highly advantageous).
Multistage roots pumps have many advantages over other pumps, and surprisingly few disadvantages or limitations.
The main advantages of multistage roots pumps is that they are very compact and quiet, enjoy a long service life, have no contact between moving parts and thus no wear, no particles generated, or any need for oil which would otherwise contaminate the vacuum system and final product.
However, multistage roots pumps have several disadvantages. These include: relatively high service costs and lower pumping performance when operating near atmospheric pressure. They are also only capable of achieving small pressure differences, which is why they are employed in a multistage format where each incremental stage is able to build upon the pressure increase achieved from the compression of the previous stage.
The Ash Air range of rotary claw vacuum pumps is the best alternative to rotary vane pumps. A vacuum claw pump is virtually zero maintenance and compared to rotary vane pumps can work at vacuum levels of 400 to 1000 mbar without overheating. Rotary claw vacuum pumps are the best choice for CNC guided wood routers.
The Ash Air range of humble liquid ring pumps is still the most reliable form of large volume vacuum generation available today. These liquid ring pumps are simple to use and very reliable, and the best option when sucked air contains a large amount of saturated gas.
Dry and oil-sealed vane vacuum pumps are robust, affordable and easy in maintenance. You can use DVP vane pumps for wide range of application, for skin packaging, holding, lifting, thermoforming.
We have a quality range of oil-sealed screw pumps for sale that are energy efficient and have low life-cycle costs.
Ash Air has been around in New Zealand since 1979, and we’ve grown into a nationwide company with international support and a
reputation for quality and reliability.We look after all things compressed air for your business!
Ash Air's range of Chicago Pneumatic, ALUP, Pneumatech, and Atlas Copco products are used extensively around the world in
industries ranging from oil and gas to food, automotive and farming, and we bring you these world-class compressors here in the land of
the long white cloud.Our technicians are compressed air equipment experts and are dedicated to addressing customer needs. Supported with
nationwide coverage, Ash Air offers one of the widest selections of compressed air, vacuum pump, and industrial gas equipment and parts
available today in New Zealand.
With Ash Air, you can count on reliability and high performance for even the most demanding applications. We focus our efforts
on the following:
Talk to the team today:
How to Operate and Maintain Your Liquid Ring Vacuum Pump
A liquid ring vacuum pump is a powerful and steadfast piece of equipment that, if well maintained, can provide years of dependable
performance. Whether you purchase a large or small unit, you can rely on a vacuum pump for smooth, consistent and relatively quiet operation
for many months on end between each inspection.
Read More…
Proportioning the Compressed Air Dryer
Trying to figure out which air dryer capacity is best for you? Here are some factors to consider.
Read More…
Maintenance budget: 8 factors to consider
Just like any other equipment, a compressed air installation also requires the necessary maintenance work during its entire
lifespan. Even though maintenance costs are only about 5 to 10% of a machine's annual operating costs, failure to budget for
maintenance can have potentially disastrous consequences.
Read More…
Do you have an idea for our #expertcorner? Let
us know!
Who we are and how Ash Air can help your business!
Reliability and Efficiency
Read more from our #expertcorner
.jpeg)
© 2024 Ash Air • Website design by Fuel
