VACUUM SCIENCE BLOG

Entries related to: industrial process vacuum

The Working Principle of Multistage Roots Vacuum Pumps

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:

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Introduction to Vacuum Coating by Thermal Evaporation

In our previous blog post, Introduction to Vacuum Coating Technology, we shared various PVD (Physical Vapor Deposition) methods and showed typical products being coated using vacuum technologies. Thin films can be adhered to metal, glass, plastics, ceramics, or paper. In this blog post we will focus on Thermal Evaporation techniques.

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How to reduce outgassing in vacuum systems

 

This blog is based on the article in Applied Science and Convergence Technology 26 (5): 95-109 (2017) R Grinham and A Chew.

There are four main ways you can reduce outgassing in your vacuum system. These are: cleaning and handling, surface treatment, passivation, and purging and backfilling. In this blog, we will take a closer look at each of these methods. 

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Introduction to outgassing

 

This blog is based on the article in Applied Science and Convergence Technology 26 (5): 95-109 (2017) R Grinham and A Chew.

There are several contributions to the gas load of a system. At pressures below ~0.1 mbar, the most dominant is often ‘outgassing’. Outgassing is the result of desorption of previously adsorbed molecules, bulk diffusion, permeation and vapourisation. Adsorption occurs via two main processes, physisorption and chemisorption, and can be described using five (or six) classifying isotherms. 

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How To Match Primary & Secondary Pumps

Secondary pumps require a primary pump to initially ‘prime’ them for operation and/or to support their continuous operation. There are several factors which need to be considered for the correct combination or ‘matching’ of primary and secondary pumps to ensure safe and optimized performance.

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Food waste at record high – how vacuum technologies help reduce waste

According to a report by the Food and Agriculture Organisation of the United Nations, at least one-third of food is lost or wasted between harvest and household. In North-America and Europe, this means more than 100 kg of food lost per capita – summing up to 1.3 billion tons annually worldwide! A reduction to this huge mass of food produced in vain would contribute greatly to reducing the greenhouse effect.

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Everything you need to know about screw pumps

Screw pumps belong to the family of dry compressing gas transfer pumps. (Learn more about the origins of dry pumps here) They are positive-displacement pumps that use two screw shaped intermeshing rotors to move gas along the screw’s axis. They are frequently used in industrial vacuum applications, often in combination with roots blowers and as oil-free roughing pumps in high and ultrahigh vacuum systems.

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Nearly Zero Energy Buildings conference summary

On 28 August 2019, Vacuum Science World contributor Dr Saim Memon hosted an international, one-day conference on Renewable Energy and Vacuum Insulation for Nearly Zero Energy Buildings (NZEBs) at London South Bank University.

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Residual Gas Analysers (RGA) explained

What is a residual gas analyser?

A residual gas analyser (RGA) is a small and usually rugged quadrupole mass spectrometer, typically designed for environment analysis, process control and contamination monitoring in vacuum systems. RGAs can monitor the quality of the vacuum by detecting (and measuring) minute traces of impurities in a low-pressure gaseous environment. RGAs can also be used as sensitive in-situ leak detectors, usually using helium.

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Working with turbomolecular vacuum pumps

How does a turbomolecular pump work? 

Turbomolecular pumps (TMPs) are kinetic vacuum pumps which operate using a very fast spinning rotor (usually rotating at between 24,000 and 90,000 RPM). Their typical operating pressures are in the high to ultra-high pressure range between 10-3 and 10-11 mbar, employing pumping speeds of between 10 and 4,000 l/s.

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