Flow Measurement

What is a target flow meter?

A target meter is used to measure the dirty or corrosive liquids, not all the fluids would be clean and we need to measure the dirty fluids and it can be done by using a target meter. A target meter can also be used to measure the gases with dust particles. The target meter would measure the impact which is created by the fluid flow on the obstruction. The target meter would use an obstruction to measure the flow the obstruction could be a plate, disc, or something else. The disc will partially obstruct the flow in the pipeline, the installation requirements are very less compared to other flowmeters. The target meter can provide good accuracy with a wider turndown ratio.

How does a target flowmeter operate?

An object is used as an obstruction to the fluid flow and the object will be mounted at right angles. The object which is used could be a disc and it will be placed at a right angle to the flow, the flow of the fluid will move the target at the pivot point. A strain gauge is used to calculate the force which is created by the flow on the obstruction. The strain gauge will create electronic output which will be proportional to the flow rate. The size of the target is selected according to the liquid that is being measured.

How is a target flow meter constructed?

The target meter can be described as a combination of the force balance transducer and an annular meter. The annular orifice is basically a circular disc and it is supported in the tubular section. The flow through the tube would reach the disc. With the help of a flexible seal, the disc is mounted on a rod, the force on the disc is measured with the help of a force balance transducer.

How to install a target flow meter?

  • If the meter is installed in a vertical position, then the medium flow direction must be from down to up
  • The valve should be installed in a way that it won’t affect the fluid state
  • If the meter is installed in the open air, then precautions should be taken in case of rainfall.
  • It should be installed coaxially with front behind pipelines so that the measuring error can be kept low because of the change in a flow state

What are the advantages of a target flow meter?

  • It can be used with dirt or corrosive fluids
  • Good operating temperature
  • This is the only flow meter that can be used to measure the solid flow
  • Very less maintenance
  • No moving parts
  • They are available wide range of sizes and models
  • These meters are easily adaptable to different fluids and flow rates and it can be done by changing the target size of the material
  • It doesn’t need any external connections, seals, or purge system
  • These flow meters would allow the unrestricted flow of condensate and also the extraneous material along the bottom of the pipe. It would also allow the uninterrupted flow of gas or vapor along the top of the pipe at the same time.

What are the disadvantages of a target flow meter?

  • Its accuracy is good at low scale and at full scale, its accuracy would vary
  • Straight pipe length is needed
  • The pressure drop will be high
  • Maximum operating pressure is low
  • Its accuracy is low in gas and liquid metering

What are the applications of a target flow meter?

We can use a target flow meter to do the measurement of liquids, vapors, and gases. The target flow meter can be used to determine the flow in slurries and it can be used for other dirty fluid measurements. We can’t use a certain flow meter because the process fluid could be corrosive or could be a chemical that would damage the flow meter so in that case, we can use a target flow meter. The target flow meters can be used for low-flow metering applications.


post-graduate in Electronics & communication.

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