Applying the proper valve is critically important. Proper valve selection can determine the success or failure of a system or process.
“Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime.”1 This is how I feel about application training. If you give a person a detailed application, target account, the appropriate product to sell, and tell him how to sell it, he will eat for a day (or until he runs out of target accounts). If you teach him the questions to ask, the information he must gather, the function and capabilities of various valve types and how to properly size and select the valve, he will eat for a lifetime.
On the surface, it seems like a daunting task. Think about it, how many applications are there? Hundreds? Thousands? For the sake of this discussion, let’s say four. Yes, four. Solids, Liquids, Gases, and Steam. Less daunting? Perhaps. We still have a lot of information to gather.
Valve selection is based on but not limited to function, size, medium, material, end connections, shutoff, pressures, flows, and actuation.
An ISA Data Sheet is a great help. Ideally the specifying or design engineer will prepare an ISA datasheet for each control valve or regulator. If an ISA data sheet is available, most of the required information will be at your fingertips. In the absence of a datasheet, a minimum amount of data is required to size the valve.
Always ask the following question, “Mr. Customer, what do you want the valve to do?” There are a large variety of valves and valve configurations to suit all services and conditions; different uses (on/off, control), different fluids (liquid, gas etc; combustible, toxic, corrosive etc) different materials and different pressure and temperature conditions. Valves are for starting or stopping flow, regulating or throttling flow, preventing back flow or relieving and regulating pressure in fluid or gaseous handling applications.2
So, what must one do to recommend an appropriate valve for a specific application? Gather as much data as possible about the operating conditions. Understand the capabilities of the various types of valves. Talk with the customer to understand what they expect the valve to do and how they expect it to perform. Remember, the more information you have, the better the recommendation you can make.
1The oldest English-language use of the proverb has been found in Anne Isabella Thackeray Ritchie’s novel Mrs. Dymond (1885) in a slightly different form.
2Valve Types, David Forbes, October 21, 2015