|What is the difference between a proportional relief valve and a safety relief valve?||Safety relief valves are designed to performance standards. They are configured to open to their maximum rated flow capacity and stay open. Proportional relief valves open in response to increasing upstream pressure and produce variable flow rates in direct relationship to the upstream pressure. They reduce flow and will re-seat with reduction in upstream pressure.
Proportional relief valve are not intended to be used as safety relief valves but as safety accessories intended to reduce spike pressures on instrumentation equipment, rather than being a primary system relief valve.
|Is there data that correlates pressure to relieving flow? Do you have and pressure vs. flow curves / charts , or formulas?||Unfortunately we do not have any such information for calculation other than the guide information in the catalog, See catalog page 3 (4190-HPRV). Valves which are not actuated for a period of time may initially crack at higher than set pressures.|
|Why is my relief valve not cracking at the set pressure?||See catalog page 3 (4190-HPRV). Valves which are not actuated for a period of time may initially crack at higher than set pressures.|
|Do we have maintenance instructions for relief valves?||The HPRV Series Relief Valves are set and wire locked in factory in order to achieve PED certification and for that reason they are not a serviceable/ maintainable part due to the fact that as soon as the wire lock is broken or removed the valve is no longer PED certified. As a result instructions are not available.|
|The catalog says if valves are not used for a while, they may crack at a higher pressure. How often should they be cycled to prevent this?||We have never conducted tests on this, but we recommend operating the valve once a month.|
|What is the shelf-life of a relief valve?||Nitrile compounds have a shelf life of 15 years, but it is not traceable after assembly unless specified in the PO|
|Would our relief valve, RL4, RH4 series, be suitable with application related to oxygen and helium?||We can provide C3 option(cleaned for oxygen service) on the relief valves. Customer will need to make the determination if the valve will work in their application|
|Is the RH4A relief valve preset at the factory?||No, but the HPRV Series Relief Valves can be.|
|On HPRV, where the orifice sizes is stated as 5.2mm, what is the flow area of the orifice in mm^2?||This is a proportional relief valve, and this data is not available.|
|For HPRV, is there any information on Kd co-oefficient values on the valve?||This is a proportional relief valve, and is not designed to give a specific flow rate.|
|Do IPD offer Brass relief valves?||No only Stainless Steel|
|Can HPRVS valves be supplied unset?||No, these need to be factory set to comply with PED.|
|Can US relief valves be rated to UV-1 ASME?||The relief valves are not certified as safety relief valves, and therefore are not UV-1 ASME Certified.|