Low-pressure relief valve is fully certified to the PED

Paul Boughton

Parker Hannifin's Instrumentation Products Division is launching a versatile pressure relief valve for low-pressure instrumentation applications up to 400psi (27.6bar). CE marked and certified to the highest Category-IV level of the Pressure Equipment Directive (PED), the new HPRV valve is supplied pre-set to any of six pressure ranges from 10-400psi (0.7-27.6bar). The chosen cracking pressure is laser etched onto the valve body at the factory. Another variant of this relief valve design is available for higher pressure applications.
Parker says the HPRV valve is a simple 'fit and forget' device for adding reliable safety, environmental and/or equipment protection to a wide variety of process and laboratory instrumentation applications. Moreover, the valve needs no testing or calibration by the end user.
In addition, parker says that each HPRV low-pressure valve is supplied as a complete item - including the spring that determines the cracking pressure - under a single order number to simplify purchasing. The valve is fully PED certified and requires no additional paperwork or approvals. Parker has additionally set up its manufacturing and assembly process to ensure short lead-times.
The valve has a 5.2mm (0.203inch) orifice and, as standard, it comes with either twin-ferrule A-LOK or single-ferrule CPI compression tube fitting ends, thereby eliminating the need for threaded connections and the potential problems that are associated with using thread sealants such as PTFE tape. Other types of end connection may be specified to suit the installation.
Over-pressures form the outlet port can be released to atmosphere, or the valve may be configured to duct media to a safe place. The cracking pressure is determined by one of six factory-fitted springs. These provide a choice of six cracking pressure ranges: 10-25, 25-50, 50-100,100-150,150-225 or 225-400psi (0.7-1.7, 1.7-3.4, 3.4-6.9, 6.9-10.3, 10.3-15.5 or 15.5-27.6bar). A locking wire may be fitted to secure the chosen pressure setting and guard against tampering.
O-ring seals adapt the HPRV valve for different types of media, and operating temperatures are -57 to 204 degrees C (-70 to +400 degrees F). Five choices of material are available: fluorocarbon rubber and nitrile rubber for general-purpose use, ethylene propylene or neoprene rubber for compatibility with a wider range of chemicals, or highly fluorinated fluorocarbon rubber for compatibility with a wide range of chemicals.
Charles Harris, the business development manager for Parker Hannifin, comments: "The introduction of these low-pressure options rounds out Parker's range of relief valves for process instrumentation applications, providing users with the means to select optimised and accurate protection for pressure-containing systems operating from 10-6000psi. The European Directive approval also gives us a distinct advantage over many of our key competitors."
For more information, visit www.parker.com

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