Quick release connectors keep gas odours contained

Edited by the Engineeringtalk editorial team Oct 31, 2006

Couplings provide the secure, reliable, quick release connections required by Robinson Brothers for use in its natural gas odorising systems.

Staubli HCB couplings provide the secure, reliable, quick release connections required by Robinson Brothers for use in its natural gas odorising systems.

HCB couplings are designed to be disconnected with the absolute minimum of spillage.

Natural gas does not have a characteristic smell; if the gas was used in this condition, leaks in the system could occur without detection, leading to catastrophic results.

Robinson Brothers of West Bromwich has been involved in the gas odorant business for over 40 years, manufacturing the chemicals that will impart the recognisable "gas" smell to alert all to the possible danger of a leak.

Robinson Brothers has a long and impressive history dating back to 1869 when the company established a tar distillery on the site.

It currently employs 235 and has a turnover in excess of GBP 25 million; the company is still family owned and achieved the environmental management standard ISO14001 in 2000 following the installation of a GBP 1.4 million state-of-the-art abatement plant that can safely treat waste products from their processes without any harmful concentrations of emissions into the environment.

Over the years the chemicals used for gas odorising have changed from tetrahydrothiophene in the 1960s to a combination of mercaptan and sulphide today.

A property of this mixture is that, even when diluted to a few parts per million, it retains the smell associated with town gas.

Consequently the handling of these chemicals needs to be strictly controlled to ensure no escape occurs that could result in a false gas leak alert.

This is particularly important when the highly concentrated odour additive, which is injected into the local gas supply, is being transferred into storage tanks.

Robinson Brothers engineers recognised that it was necessary to have reliable leak and odour free connectors between their odorant transfer hoses and the gas distribution sites.

They called in Staubli for advice on the type of connectors they should use.

Tony Quinney, Site Engineering Manager at Robinson Brothers commented: "We had good experience of Staubli's quick release connectors on other high integrity applications so, when this requirement arose, they were the natural choice to advise on a dry break, reliable and robust coupling with next to no loss in containment".

Staubli recommended a connector that had only recently been introduced to its range, the HCB 28, which is designed specifically for applications where any leakage at all is absolutely unacceptable.

HCB couplings are of a flush faced, nonspill design, preventing any air inclusion in the system when connecting as well as avoiding any spillage on disconnection.

The initial HCB range introduced a few years ago included sizes up to DN25, in response to market demand for larger sizes, the range has been extended up to DN80 sizes.

The new larger couplings are designed for use in bulk filling situations when any leakage at all must be avoided.

These couplings were ideal for Robinson's challenging gas odorisation application requirements.

All HCB connectors feature the Staubli patented bayonet locking system that provides a safe, quick and reliable connection.

The locking system provides a positive feedback response, ensuring a high integrity connection and eliminating any chance of misconnection.

On the new larger sizes, the coupling can be fitted with a hand operated wheel if required.

The changeover to the new connectors at Robinson's started in April 2005 following extensive testing.

Gradually each of the odorisation stations is being fitted with a specially developed version of the HCB 28 couplings as well as all the hoses and equipment on their fleet of delivery vehicles.

A set of HCB 28 couplings have been on test at Robinson's for over 2 years.

No leaks have occurred in any of the couplings and they have simplified the refilling process significantly.

Other applications for HCB couplings are in the secure loading and unloading of wagons and storage vessels, distribution units and fluid transfer systems as well as quick, safe connection of refuelling hoses.

Robinson Brothers which manufactures speciality chemicals, primarily for the pharmaceutical and rubber markets, is now reviewing additional applications where the benefits of Staubli leak free couplings can be used to advantage.

Like all Staubli couplings, the complete standard HCB range of connectors is available on rapid ex-stock delivery to all parts of the UK.