Making the Flow of Liquids More Systematic

by Will S. Flow Meter and Switches

The purpose of a control valve is to regulate the flow rate of liquids through pipelines in a system. And this is accomplished by placing a valve in the path of liquid flow. It usually offers resistance to the liquid flow, where process control restrains the liquid flow and resistance by an indicator. This indicator is actually borrowed from the sensors in a plant. It must be noted here that when a manufacturer supplies a control valve, it is attached to an actuator, which make use of this control indicator for stimulating the ultimate control component. The different varieties of valves are categorized by an association between the flow rate of liquid through a valve and the position of a valve stem. Three main types of valves depending on the association between the flow rate of liquid and stem position are:

·         Equal Percentage
·         Linear
·         Quick Opening

The association between the stem position at a steady pressure drop and the flow rate through a valve is known as the Inherent Valve features. The association between the stem position for a valve and the flow through a valve installed in the process order at changing pressure drop is termed as Effective Valve features.

In order to restrain the liquid flow, a quality liquid flow control valve is the most appropriate choice to decide on. This is the best system, which makes certain that the flow will be controlled according to the standards. The pre-set signals in the valves certify that the guidelines for the user are clear. Based on these guidelines, the functions in the controlling process take place. In many cases, it is suggested to decide on specific limitations, which is not harmful. With this, the controlling process will run seamlessly. If the specific limit is fixed at a high rate or altered anyhow, then it may cause an alarm situation for which the user must take imperative and quick action. To be sure that the liquid level does not cross the specific limit, the valve is opened, which will simply drain out the additional liquid. Instead of wasting the liquid by setting its flow high, it is better to set its limit at a reasonable level. Therefore, it is suggested to use a high quality liquid flow control valve for systematic flow of liquids.

Mainly, the control valves are categorized into two parts, namely the body and the stem. The stem integrates the plug, the valve stem, and the valve seat. And the body integrates the housing characteristic that has the associations, which bring in the supply line and the delivery line to join together. The alteration in the valve takes place for bringing about a move from resistance to flow, and this is actually performed by the stem. The plug and the stem shift in the upward direction and this causes an increase in the size of the opening place between the plug and the seat.

Progressively this causes an alteration in the flow rate. And the direction in which the liquid flow shifts is considered as of major importance. In case the direction is changed, the flow also will be turned triggering problems in the valves. Flow meter accuracy and repeatability are essential to the success of industry where liquid flow rate measuring devices are used. Therefore, they are diligently analyzed according to set criteria. Numerous techniques are used to make sure the liquid flow rate measuring device is functioning properly. Depending on the requirements of the flow meter and the environment where it is being used, testing of liquid flow rate measuring devices can occur via three routes: calibration, in-field proving and verification.


The purpose for calibration is to find out whether deviations are there because of process practice or manufacturing. As a result, calibration procedures may occur in two situations, in re-calibration after use or in the last step during manufacturing. There are various design standards, which manage calibration systems such as master meter comparison, gravimetric methods, and volumetric methods.

In-field Proving

This method may be conducted in situ with a customer or out-of-process with a master meter, scale, transfer standard or flow proving cart. Within in-field proving, the precision of the proving meter must be at par with the anticipations of the customer. Test runs can take place continuously or combine into a whole for comparison. In in-field proving proficiency rests with the holder of the master meter, the capability to restructure test conditions during the development of the process meter and employed practices.


Liquid flow rate verification is used to confirm long-term stability. Verifications can be administered comparisons conducted under actual flowing conditions or electronic simulations without real flow. Verification tests are relied upon to satisfy agency, government or quality systems requirements.

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About Will S. Freshman   Flow Meter and Switches

7 connections, 0 recommendations, 38 honor points.
Joined APSense since, March 28th, 2018, From Mountain View, United States.

Created on Mar 28th 2018 06:51. Viewed 653 times.


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