Valve and pipe designer and manufacturer Rexus Trading’s AirFlo Variable Orifice air-valves are being used on several major pipelines in South Africa and in Southern Africa, says Rexus Trading MD Allistair Balutto.

“Ninety-six DN300 AirFlo air-valves are in use on a South African water board’s 3.5-m-diameter pipeline, in Gauteng,” he states, highlighting that the pipeline was successfully commissioned in February and has resulted in AirFlo air-valves being used for several other major projects by the same water board.

“Rexus Trading has successfully supplied AirFlo Variable Orifice air-valves in every size and pressure range, as well as on water and sewer applications at several projects in Southern Africa,” he adds.

In addition, Balutto adds that the DN300 AirFlo Variable Orifice air-valves are among the largest ever to be designed and manufactured worldwide.

He says this air-valve range is 100% locally manufactured and is compactly designed, aesthetically pleasing and cost-effective, compared with other designs.

“The major benefit of the AirFlo Variable Orifice air-valves range is that it provides exceptional overall pipeline performance, with easy installation and minimal maintenance,” states Balutto.

The air-valves are designed for use on water, sewerage and irrigation pipelines.

“They are designed to automatically release air when a pipeline is filled, to draw air into a draining pipeline to prevent pipeline collapse and to release pressurised air from a pipeline that is hydraulically filled,” he explains.

In addition to these functions, the AirFlo Variable Orifice air-valves automatically prevent destructive phenomena, such as surges and water hammer, from occurring in pipelines.

Moreover, Balutto notes that the valves’ patented technology supports its variable orifice design, which senses the velocity of air discharge and automatically and infinitely adjusts its outlet orifice to restrict air outflow in a controlled fashion.

“The variable orifice design slows down an advancing water column in a pipeline and, thereby, prevents water hammer when the valve closes,” he adds.

Product Uptake and Development

“Rexus Trading has received a positive response to its air-valve technology since its introduction in late 2011 and sales have been brisk, owing to the market embracing the AirFlo Variable Orifice air-valves as the pinnacle of current air-valve technology,” states Balutto.
 
The air-valve range overcame the perception that pedigree in age signifies pedigree in performance, as there was an initial reluctance among companies to change their existing specifications to include the new AirFlo Variable Orifice air-valve technology.

“This reluctance was overcome on several levels, owing to some milestone projects providing proof of third-party test performance and the designer of AirFlo Variable Orifice air-valve authoring a book that highlights the evolution of air-valve technology and the technical reasons why these valves provide superior performance, compared with current designs,” Balutto recounts.
 
Moreover, he emphasises that the AirFlo Variable Orifice air-valve is one of the most researched air-valve designs available in the market.

“Research and development included investigating more than 30 previous patents as far back as 1936 and reviewing more than 137 technical papers,” he says.

In addition, Balutto says several practical tests were carried out on the AirFlo Variable Orifice air-valve, including comparative testing of every locally available air-valve design, to ensure that it is a high-quality and high-performance design.

He says it is one of the few air-valve designs that has undergone third-party testing and the only air-valve system whose performance has been verified by the South African Bureau of Standards.
 
Rexus Trading has developed several training programmes, which cover many aspects of pipeline design, pipeline valve selection and pipeline materials selection. 

The company currently provides a free-of-charge South African Institution of Civil Engineering-accredited course for engineers on the advancement of air-valve technology.

“This highly sought-after one-day seminar for engineers, covers all aspects of surge and water-hammer prevention and air-valve technology training,” Balutto concludes.