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New LESER Change-over Valve Ensures 24/7 Plant Operation

From refineries and cooling systems to tank farms, safety valves protect plants against damage caused by overpressure. Safety valves undergo routine maintenance to make sure they always operate flawlessly. In processes where only one single safety valve is installed, the entire plant may have to be shut down for valve maintenance. The same applies to repairs or valve replacement. "To avoid a full shutdown, we recommend installing a spare safety valve. This requires a Change-over Valve which allows the switching between the active valve and the standby valve. We're excited that we are now able to supply a solution that is both technically innovative and economic," said Joachim Klaus, Managing Director of LESER GmbH & Co. KG.


The idea behind the LESER Change-over Valve: It enables a second, identical safety valve to be connected to the piping system. Whenever the active valve requires maintenance, the Change-over Valve allows the standby valve to be activated in its place to ensure continued protection of the plant. "Our new Change-over Valve allows a plant to run 24/7, which boosts productivity significantly," says Klaus. This ability addresses a key concern among industries using safety valves. The consequences of a plant shutdown can be fatal: "An unplanned shutdown can quickly cause millions of dollars in financial damage to the company, especially in systems carrying critical media or in processes requiring continuous operation,” Klaus points out.


Extensively tested

LESER’s stated goal when developing its Change-over Valve was to reduce the pressure drop below current typical levels, thereby optimizing the flow resistance coefficient. According to regulations, the pressure drop in the pipeline connecting a pressure vessel to a safety valve must never exceed 3 per cent. "Our experts developed about 50 different design variants and subsequently ran tests involving all relevant departments to assess manufacturability,” Klaus explains. The result is a functional principle that is globally unique: a robust, maintenance-free, flow-optimised valve design that features minimum pressure drop and has withstood rigorous lifecycle tests. The flow resistance coefficients of the LESER Change-over Valve were determined and optimized using computational fluid dynamics simulations (CFD) as well as tests at an independent test lab.


Perfectly matched components

To allow its Change-over Valves to be used in as many installation scenarios as possible, LESER developed a modular design. The Type 330 Compact is used for standard pressure drop requirements. The Type 320 Flow Change-over Valve was designed specifically for the demanding pressure drop requirements typically found in applications involving additional piping or high-capacity safety valves. As for set of elbows and inlet body, LESER can provide custom solutions by combining various standardized components. More than 50,000 different configurations are possible. What makes this solution an exceptional novelty and the most economical solution in the market is the fact that on lockable combinations, The Change-over Valve at the inlet of the safety valve does not have to have the same nominal size as the Change-over Valve at the outlet side of the safety valve. “Our Change-over Valves compensate for both, flange distances and disc travel differences, by using a combination of standardized components. This allows us to combine different nominal sizes and pressure ratings without having to use reducers, welded connections or other contraptions," says Klaus.


Operation is easy: the changeover from one safety valve to the other works by turning the hand wheel. Further benefits: It is easy to see at any time which safety valve is active. It is impossible to close both safety valves at the same time, which means that continuous 24 / 7 operation is ensured.


Fast availability

By combining the standardized components all common customer specific variations can be configured.

Since the new Change-over Valve is manufactured directly at the LESER factory in Hohenwestedt, LESER can guarantee a fast, delivery time as low as four weeks. LESER is now able to provide its customers with a complete, optimised solution from a single source. In a first step, LESER is offering the new Change-over Valve in sizes up to DN 100 / 4’’. In a second step, larger sizes will be added by end of this year.


With fast delivery, simple designs and outstanding performance data, LESER’s proven safety valves and the new Change-over Valve combined provide optimum and safe solutions that ensure continuous, smooth operation of complex industrial installations.


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