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An entire flow measurement system should be operated within its constraints in order to provide accurate flow measurements, according to Spitzer and Boyes.

This means that each component of the flow measurement system should be considered to ensure that it is operated properly.

For example, turbine flowmeters should be operated above a certain Reynolds number.

Failure to do so will cause K-factor shifts that can result in measurement error.

Some turbine flowmeters can use flow computer functionality to correct this error by calculating the Reynolds number in conjunction with a theoretical or experimental relationship between the Reynolds number and the flowmeter K-factor.

However, the correction is not necessarily performed perfectly because there is an uncertainty associated with the parameters used to calculate the Reynolds number as well as an uncertainty associated with the K-factor calculation.

There are additional parameters that are typically ignored but that should be considered.

Process and ambient temperature can have a profound effect on the quality of measurement.

For example, a flow transmitter designed to operate in ambient temperatures up to 60C may operate properly in a boiler house during the winter when the temperature is 30C.

However, it can operate sporadically in the summer when the ambient temperature approaches 70C in an enclosed space near the steam pipes in the middle of the afternoon on a sunny day.

Ambient conditions can also effect flowmeter operation.

In one such instance, a flowmeter operated properly during the winter but would suddenly measure zero flow in the middle of the afternoon on warm summer days.

The cause of the problem was traced to the sun warming the pipe to the extent that the liquid would vaporise and cause the flowmeter to stop operating.

This was a major issue because zero flow would cause the reactor to trip.

By the time the reactor was restarted a few hours later, the ambient temperature was lower and the flowmeter operated properly (until the next warm day).

Even the electrical power supply can cause problems, albeit not often.

If the power supply voltage is outside of its specifications or if it varies, flowmeter operation and performance can suffer.

In general, we tend to concentrate on how the process affects flowmeter operation in the context of a given flowmeter technology.

However, we should not forget that other seemingly trivial factors can influence the measurement, according to the company.

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