Getting the Gas Out

Current events seem to have (temporarily) altered the tone of television interviews from cordial/congenial to confrontational. Whereas the person being interviewed used to answer the interviewer’s questions, the person being interviewed now seems to deliver their preplanned message no matter what the question. More than one interviewer has stopped the verbal tirade and actually lectured the person being interviewed (sometimes in no uncertain terms) as to the inappropriateness of not answering the question.

Most vendors are generally knowledgeable of their products. If there are questions beyond that person’s knowledge and expertise, most have no problem contacting the proper person in their organization for clarification. Yet, the tone of recent interviews reminds me of a particular vendor presentation.

Some years ago, an officer of a company came to chat. I politely listened to his presentation about his flowmeters. When he finished, I wanted to know how gas is removed from the flowmeter so that the flowmeter can remain full of liquid at all times. After all, special features with bells and whistles are nice, but if the flowmeter does not remain full of liquid, the quality of measurement can suffer.

What was the vendor’s response to my question?

A. The flowmeter is not self-filling, so the user has to run high flow through the flowmeter to remove the gas before zeroing the flowmeter.
B. The flowmeter is not self-filling, so the user has to determine when gas accumulates in the flowmeter during operation and run high flow through the flowmeter to remove the gas.
C. The flowmeter is not self-filling, so the user has to determine when the piping in the area of the flowmeter becomes partially empty and run high flow through the flowmeter to remove the gas.
D. Once the gas is removed from the flowmeter, the flowmeter should operate accurately.
E. The flowmeter has many virtues, including…

Answers A, B and C describe the realities associated with the installation of this flowmeter. For proper operation, the flowmeter must remain full of liquid. Any accumulation of gas in the flowmeter provides the potential for degradation of the measurement. Collectively, Answers A, B and C describe actions that the user should take to maintain accurate measurement. In many applications, these procedures can be impractical, unfeasible and inconvenient. Answer D is a true statement, but it does not address the issue of reintroducing gas into the flowmeter. The response given to my question was Answer E. It really did not matter what the question was — the answer was already predetermined.

Additional Complicating Factors
Some suppliers provide a procedure in their instruction manual to remove gas from their flowmeter. Other suppliers address the issue by stating that gas must be removed from the flowmeter for proper operation. The user is advised to examine the instruction manual before purchasing. 



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