Replace the flow meter with a pressure transmitter
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In my practical work, I encountered a situation where pressure transmitters were used to measure the pressure in pipelines, as a substitute for flow meters. Is this done to save money? Are there any disadvantages?
You need to specifically check whether the pressure transformer can be used as a differential pressure sensor; if it can, then differential pressure measurement can be used for flow measurement on site, and there will be no problem.
Hearing about using a pressure transmitter in place of a flow meter was new to me; I’ve now seen it in action.
Pressure and flow rate are different parameters; measuring pressure does not indicate the amount of flow rate. How can it be replaced...
What I have observed is that when using fluid cooling, the pipes are about 1 inch in diameter or larger; the flow rate is not high, and low as well as very low alarm levels are required； The original design used a flow meter, but in practice a pressure transmitter was used. The return line is not controlled by a valve, and the pressure transmitter is installed at the inlet of the equipment. It is said that it saves money.
The flow velocity of the fluid in a pipe cannot be determined by pressure measurements, as there is no inherent relationship between the flow velocity of the medium and pressure. You can think about it: there is high pressure inside a steel cylinder filled with compressed gas, so the flow rate is zero ； The pressure in atmospheric circulation isn’t very high, right? But the wind speed of the strongest typhoons can reach over 100 meters per second. The flow rate of the medium in the pipeline is related to the pressure difference; you should use a pressure reducing transmitter in combination with a throttling element to measure the flow rate.
This post was last edited by qugd on 2015-6-11 at 11:57. I think you must have seen it wrong. The flow velocity inside a pipe cannot be determined by pressure measurements. This is the basic principle. In a bucket filled with water, as long as it doesn’t leak, how is the flow rate of the water inside related to pressure? But when there is a small hole at the bottom of the bucket and water flows out through that hole, it is because of a pressure difference between the water inside the bucket and the water outside the hole that causes the water to flow outward. The same principle applies to other fluids as well.
I know you’re right; it makes sense. Just as in the example you gave. In real work, what I say is also true. I also know that doing this makes no sense in principle. But it really is done this way.
That works too; it helps to expand one’s knowledge, but the process requires a series of data conversions, I guess