Central Gas System For Speciality Gases

What is a central gas system?

A central gas system is a distribution system for gas from a container to one or more points of use. For Speciality gases, the choice of components in the system will be determined by the properties and purity of the gases.

A central gas system normally consists of :

• A central store for containers where gases are separated. According to their physical properties (the gas storage is located so that it can easily be accessed by lorry)
• A pressure reduction unit (supply board) by the container with a valve for purging when connected to a new container
• A pipe system which distributes the gas to the points of use. A pressure reduction unit at the point of use which reduces the pressure to the correct working pressure

Necessary safety equipment such as safety valves, flame arrestors, monitoring systems etc. are integrated in the system as required and/or depending on the properties of the gas you plan such a system.

Why choose a central gas System?

• Increased safety
• Improved working environment
• Improved economy
• Required by authorities

- By avoiding transport of loose, Heavy gas cylinders, and with reduced gas pressure piped to the point of use, the risk of accidents is greatly reduced. Low gas pressure means reduced gas discharges in case of leakage.

- When changing cylinder, the switch boards will provide a continual supply of gas to all points of use.

- Purchase of gas can be made in large volumes, and thus stock is reduced.

- A Central gas system provides the best way to monitor pressure and leakages, and can be connected to central alarm and emergency functions. If there is a fire in the building, the same function can be used to shut off all gas supply.

- The government’s requirements regarding the environment and safety are most fully met with the installation of a central gas system. Before installation, an application for approval is sent to the local authorities. When storing large volumes of combustible gases, this application must also be sent to the authorities.

VCL, total supplier of central gas systems

VCL has many years of experience in supplying central gas systems for speciality gases. We can also offer expert councelling to help you plan such a system.

Following an assessment of demand together with the user, we plan the system, install it and carry out a final check before handing it over.

A project manger will be assigned to follow up the project from the assessment of demand to hand-over of the system.

After implementation of a central gas system, we can offer:

• A service agreement with, e.g.,Preventive maintenance
• Courses and training for new user

Assessment of demand and planning

The selection of components in a central gas system depends on the properties and quality of the gas and on the user’s requirement.

In order to maintain the gases purity throughout the distribution systems, all components from the cylinder to the point of use must be of such a quality that they do not introduce impurities to the gas.

The quality of the components used for speciality gases is often defined with a guaranteed leak rate in order to prevent retrodiffusion. Retrodiffusion is gas molecules from the surrounding atmosphere diffusing into the system and contaminating the gas (e.g. O2 and H2O).

The choice of material quality is decisive for the gas quality .A pure and smooth surface reduces the risk of particulate and molecular contamination, and is simpler to purge clean. This is one of the advantages of steel tubes compared to e.g. copper tubes. For reactive gases, it is also important for safety reasons to choose the correct material quality.

Installation

Specially trained assemblers are used for the installation of speciality gas systems. The system is installed on the basis of purity and safety factors. In order to maintain the required purity in the Gas, automatic pipe welding is used, with compression connections. Together with approved cleaning procedures for speciality gas systems, these are of great importance for the results.