Providing innovative gas detection equipment to the utility industry

In the past, gas detection was often based on chemical reactions that caused a change in the electrical resistance in the sensor of an instrument. Such instruments were often slow to react and frequently cross-sensitive to other gases. 
 

An alternative was provided by flame ionization detectors. These burn a sample of the gas and detect ions released in the process. Such detectors are accurate and robust, but can be cumbersome. When this limits operator mobility, productivity can suffer.
 

Unlike the previous two technologies, infrared detectors are more robust and require less operator maintenance. Detectors using this technology do not chemically bind to the gas or alter the sample in any way, but simply illuminate it with infrared light. This offers many advantages, including fast response and, most importantly, fast recovery, enabling faster leak detection and pinpointing. The uniqueness of the technology offered by Southern Cross is that it uses infrared detection over the entire desired measurement range.

The sensor system in the IRwin methane leak detector, combined with the in-built gas chromatograph, allows the user to identify whether the sample is indeed natural gas. Alternatively, it could be swamp gas resulting from the decomposition of organic material in the soil or propane gas leaking from a private installation nearby. By identifying the type of gas, the leak can be identified with certainty before committing resources to excavation work.

In the past, samples were often sent off for testing, which meant a long wait for results. Now the results are delivered instantly, with the gas composition of the sample shown as a graph on the digital display and a description in plain text, for instance "NG with Ethane Detected".

Additionally, there is no longer any need to drill rod holes around the suspected area to find the location of a leak. Once a leak has been detected, its exact location can normally be pinpointed within 10 minutes using the vacuum bell supplied with the unit.

One of Southern Cross' customers is the Cullman-Jefferson Counties Gas District, which operates a 1,000-mile network in central Alabama, based on the gas pipeline from Birmingham to Cullman.

"We're making huge savings. We have a statutory requirement to conduct regular surveys of the gas network to look for leaks. It is one of our most costly operations. Surveying one-fifth of the network used to take us four to six months. Now we can do it in two and a half to three months, saving between one-third and half the time required," says Keith Blackwood, the company's director of construction and engineering.