^ New generation of gas non-return valves

Selected by Daniel Sweet

German manufacturer Witt calls its new series “Ultra”. This designation alone conveys the extraordinary performance characteristics. Size, weight, flow rate, opening pressure, operating noise, and service life: All better than what is currently available on the market, according to the company’s recent press release.

The Witt-engineers have, the release continues, completely redesigned the non-return valve. Inside the extremely compact design lies the secret: an improved valve system with fully optimised gas flow. This allows more flow for the same size, or in other words, the smaller size still allows the full flow. As a result, the Ultra valve is now smaller and lighter than others and much quieter. The more typical fluttering of the valve at certain flow and pressure conditions is now almost non-existent. In addition to lower noise emissions, this also means less stress on the valve and therefore longer service life. This is a clear cost advantage for the user. The response behaviour is extremely good, typical for Witt, and the pressure drop is minimal due to the very low opening pressure of approx. 4 mbar. Especially for applications in the low pressure range, the new Ultra is an ideal choice.

Clear user benefit

Especially in burner systems’ design, compactness and energy efficiency are essential. Witt’s new development meets these demands: small size, low weight, high flow rate, low pressure drop, quiet operation. “We offer users the best valve currently available,” says Witt sales manager Andrew Smart. “This enables them to build state-of-the-art equipment and strengthen their position in the market”

There is also a clear user benefit in pipeline construction. Thanks to the ultra-low pressure drop and the high flow rate of Ultra non-return valves, smaller nominal diameter pipelines will deliver the necessary flow of very low pressure gas. The corresponding economic advantages are very significant.

The valve is flashback-arresting when burning methane up to 2 bar in air, in accordance with DIN EN ISO 5175-1 and -2. This means that the non-return valve can be used without a separate flashback arrestor. One fitting instead of two is therefore sufficient, and the pressure drop is lower. The benefits are lower costs and a more compact design. Thermal processing applications of this kind are described in ISO 13577-2 and DIN EN 746-2.

Modular system

A modular system allows configuration according to customer requirements. Need to specify the housings to be of stainless steel, or of aluminium for ultra-light construction? Sealing materials such as FPM, EPDM or FFKM for corrosive conditions, use for acetylene or temperatures above 70°C? With or without filter in the gas inlet? With the Ultra, everything can be combined seamlessly and precisely as specified, Witt states.

The valves are cleaned for use with oxygen in accordance with EIGA guidelines. The elastomers used have been declared by BAM (German Federal Institute for Materials Research and Testing) as suitable for use in plant components for oxygen (BG RCI data sheet M 034-1).

The Ultra series offers the lowest possible opening pressures at around 4 mbar at 16 barg maximum operating pressure. The valves are suitable for city and natural gas/methane, as well as LPG/ propane and hydrogen. They are also suitable for non-flammable gases and compressed air. Owing to its perfected high-quality elastomer seal, the spring-loaded valve system is permanently “technically leak-tight” externally, as per the relevant standards. The non-return valves can be installed in any orientation and are available with G or NPT threads from ∞ʺ to 2∞ʺ. Each unit is performance tested before shipment.

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