It is not totally clear what you are asking, but I'll take a guess. A "pop" relief valve has a "huddling chamber area" that throws the valve open. The pressure must reduce below the set pressure before the valve will close. A proportional relief valve does not have a huddling chamber and it modulates with the incoming pressure, a lot like a control valve.
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
I will upload the two files. Manufacturer Fitok is for proportional relief valve and manufacturer circle seal for inline relief valve.I would like to know the difference between proportional relief valve and the inline relief valve.
From the catalogue data posted I can comments as follows;-
The comments Latexman advised earlier are basically correct - when Pressure Relief Valves are discussed in the API-526/ASME I, VIII sense.
In such cases you get
Safety Valves (pop opening on compressible fluids)
Relief Valves (proportional* opening with rise or reduction in pressure) *theoretical but difficult with spring loaded designs
Safety/Relief Valves - designs that cater for both (also used a general term - as is Pressure Relief Valve/Device)
The above can be spring loaded or pilot operated designs in the case of valves. All are generally right angle pattern.
However, many people (including the subject manufacturers) simply use loose terms such as relief valve for all types. Proportional type can and should only be limited to designs that can actually modulate and then on incompressible fluids, liquids, only. It is mainly prefered that proportional operation is used to prevent system/piping shock etc.
The Fitok open/close chart shows a linear lift and reseating - that is proportional.
The CircleSeal valve is an in-line valve (rather than end of line) with a non API design that allows a pop lift and reclose through a straight through design. These types can also be called, safety valves, relief valves, pop off valves, inline relief valves, air release valves etc., etc. These are also relatively low pressure.
Now. What I have stated is true in the ASME/API sense which most of the world uses besides USA. In the European Union, there is only one name and that is Safety Valve for all designs and applications. However, API/ASME is used and understood.
For further info on Pressure Relief Valves, please see attached Emerson PRV Engineering Handbook (read Anderson Greenwood Crosby). Page 2.1 starts with some definitions.
Hope that helps.
Per ISO, only the term Safety Valve is used regardless of application or design.
