Vacuum system, operation technology

Terra Vac has developed Dual Vacuum Extraction (DVE) technology for the extraction of volatile organic compounds (VOCs) from groundwater and sod. DVE combines a soil vacuum extraction system with a groundwater recovery system. DVE wells operate below the water table and allow for extraction of VOC-contaminated groundwater and volatilization of VOCs in the soils above the water table. 

Since the launch of the first commercial quadrupole ICP-MS instrument in 1983, the technology has evolved from large, floor-standing, manually operated systems, with limited functionality and relatively poor detection limit capabilities, to compact, sensitive and highly automated routine analytical instruments. In principle, all ICP-MS systems consist of similar components a sample introduction system, the ICP ion source, an interface system, the mass analyser, the detector and a vacuum system [8,11]. 

In spite of the enormous use of vacuum processes, detailed knowledge of vacuum technology is often lacking. Design calculations are often attempted with incomplete or inadequately-interpreted data and, even with well-designed systems, operators may lack the confidence to use them optimally and often struggle to solve relatively small problems when they arise. In both cases, at some cost and delay, there is complete reliance on vacuum equipment manufacturers appraisal. 

Chapter 6 examines what, in the authors opinion, are three important applications of vacuum technology in the chemical sciences. First, its use in chemical technology is clearly defined and, in many applications, the requirement for systems operating below 10 6 Pa is obvious. In both cases, typical systems are considered and quantified. The third topic concentrates on a technique (differential pumping) which is widely used in systems where high- and low-pressure areas must be interfaced. Specific systems are discussed to illustrate the usefulness of the technique. 

For the user, this knowledge means that the desired operating pressures cannot be achieved with the selected vacuum technology or that the operational safety of the vacuum system may be impaired. 

Brine Dechlorination. Operation of the primary dechlorinator should be established next. It is not easily possible to simulate actual dechlorination. However, where vacuum dechlorination is used, it is important to establish that the vacuum and condenser systems operate properly. In the case of a conversion from mercury-cell technology, this may already be established. 

From the operational point of view, reliable vacuum systems are a prerequisite for mass spectral measurements. In most cases, manufacturers apply differential stage pumping to achieve the required pressure range(s). Rotary pumps are used to provide an initial vacuum of approximately 10 to 10 Torr. High-vacuum pumps such as diffusion pumps (10 to 10 Torr), turbomolecular pumps (10 to 10 Torr), and cryopumps (10 to 10 Torr) are used to reduce pressure ftorther. Adequate knowledge in vacuum technology is essential in instrument design however, this is also beyond the scope of this chapter. 

Vacuum engineering The design and construction of a vacuum system to meet processing requirements. This includes the design trade-offs that make the system more amenable to operation, cleaning, and maintenance. See also Vacuum technology. 

Vacuum technology (vacuum technology) The operation, cleaning, maintenance, and repair of a vacuum system so that it continues to meet processing requirements. See also Vacuum engineering. 

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