The centralized gas delivery system is actually necessary when a large amount of gas is used. A well-designed delivery system will reduce operating costs and improve productivity and enhance safety. The centralized system will allow all cylinders to be merged into a storage location. Centralize all cylinders to simplify inventory control, simplify and improve steel bottled. Gas can be separated according to type to improve safety.
In a centralized system, the frequency of replacing the cylinder is lowered. It is achieved by connecting multiple cylinders to the manifold in the group, so a group can safely exhaust, supplement, and purge, while the second group provides continuous gas services. This type of manifold system can supply gas for a variety of applications or even the entire facility without having to equip each use point.
Since the cylinder switching can be done automatically by the manifold, a row of gas cylinders will be even exhausted, thereby increasing gas utilization and reduces cost. Since the cylinder replacement will be carried out in isolation, controlled environments, the integrity of the delivery system will be better protected. The gas manifold used in these systems should be equipped with a check valve to prevent gas reflow and clear assemblies from eliminating the replacement of contaminants into the system. In addition, most gas delivery systems can be configured to indicate when to replace the cylinders or gas cylinders.
The gas purity level required for each use point is extremely important to design gas delivery systems. The gas purity can be simplified using a centralized system as described above. The choice of construction materials should always be consistent. For example, if you use a research grade gas, all stainless steel structures and no membrane sealing shut-off valves should be used to eliminate the pollution of the airflow.
In general, the purity of three levels is sufficient to describe almost all applications.
The first stage, is commonly described as multi-purpose applications, with the least stringent purity requirements. Typical applications may include welding, cutting, laser assist, atomic absorption or ICP mass spectrometry. Manifold for multi-purpose applications has been economically designed to ensure safety and convenience. Acceptable building materials include brass, copper, TEFLON®, TEFZEL® and VITON®. Fill valves, such as needle valves and ball valves, are typically used to cut off flow. The gas distribution system manufactured at this level should not be used with high purity or ultra-high purity gases.
The second level is called high-purity applications that require higher levels of anti-pollution protection. Applications include laser resonant cavity gases or chromatography, which uses capillary columns and system integrity is important. The structural material is similar to the multi-purpose manifold, and the flow cutoff valve is a diaphragm assembly to prevent contaminants from spreading into the airflow.
The third stage is called ultra-high purity applications. This level requires the components in the gas delivery system to have the highest level of purity. Trace measurements in gas chromatography are an example of ultra high purity applications. This level of manifold must be selected to minimize the adsorption of trace components. These materials include 316 stainless steel, TEFLON®, TEFZEL® and VITON®. All pipes should be 316sss cleaning and passivation. The flow shutoff valve must be a diaphragm assembly.
Recognizing that components suitable for multi-purpose applications may adversely affect the results of high purity or ultra-high purity applications, this is especially important. For example, the exhaust gas of the neoprene diaphragm in the regulator can lead to excessive baseline drift and unsolved peaks.