As an instrument engineer in a refinery I always kept a cheat sheet with question that I would need answered when it came to selecting instrumentation such as control valves, pressure regulators, flow transmitters, etc.
My goal today is to provide you with five key pieces of information your local sales office will need to help you begin selecting a pressure reducing regulator and–more importantly–why the information is important.
1) Process Fluid
Process fluid or process medium is required for a couple of reasons. First, in order to select the correct type of regulator we must first know if we are dealing with a gas or a liquid. Second, because the process fluid, in most cases, will come into contact with the diaphragm we must make sure they are chemically compatible. If you are dealing with specialty chemicals, MSDS sheets are helpful.
2) Inlet and Outlet Pressure (Maximum, minimum, and normal)
Maximum, minimum and normal operating pressures are important for both the inlet and outlet of the regulator for a number of reasons, including calculating the required CVs, selecting a regulator with an acceptable body and casing pressure rating, and determining the minimum differential pressure across the regulator. For inlet and outlet pressure your sales engineer should be informed of any abnormal conditions such as large pressure drops or minimum droop requirements, as different regulator types or configurations maybe required.
3) Flowrates (Maximum, minimum, and normal)
Flowrate is used to determine the size and type of regulator that best fits the application. For large flowrates in most cases a pilot operated regulator (i.e. Type 1098) is required versus a self-operated regulator (i.e. Type MR95) which is typically smaller in capacity. Yes, you will need to provide minimum, maximum and normal flowrates. Depending on the process fluid and applications, the turndown for regulators can vary.
4) Temperature (Maximum and minimum)
Temperature refers to the process fluid temperature and is really only required when your process fluid temperatures are “extreme.” In general, you only need to provide specific temperature information if your process fluid temperature is less than 40°F or above 90°F. Temperatures outside of these parameters will require a sales engineer to confirm the proper metal and elastomer material for the regulator
5) Application
Finally, one of the most important (and probably least thought about) piece of information is the application. Regulators are extremely versatile devices and different configurations can be used to get different results. For example, installing a second pilot on a fuel gas pressure regulator to a boiler can increase the speed to help ensure a smooth start-up. When talking with your sales engineer explain the application in detail so your sales engineer can ensure the correct configuration is specified. For example, instead of simply saying “fuel gas service,” try “main fuel gas feed to an industrial boiler.”
Keeping this checklist of required information can help you spec in a regulator faster and with less back-and-forth with others in your refinery. Of course, if you are having trouble collecting any of this information, you can always ask your sales engineer if a piece of information is really required for selecting a device for your application.