Flow meters or also called flow sensors are devices used to calculate volumetric, nonlinear, mass, or linear flow rate of a gas or liquid. When it comes to selecting and picking out flow meters, a person must consider a few factors, for example, failure history, availability of spare parts, plant personnel's experience with maintenance and calibration, and so on.
Also, it is suggested or advised to compute the cost of installation after taking these steps. One of the generally known flow measurement errors is the opposite of this order: rather than picking a flow sensor which will adequately perform or function, an effort is made to give grounds for the use of an instrument because it's affordable.
Keep in mind that those low-priced purchases can be, for the most part, the most expensive installations. For a little help, we will help you better understand and comprehend flow sensors. So, read on!
Basic Steps To Select the Correct Flow Sensor
Okay, so the first step in choosing the right flow meter is to ascertain if the flow rate info must be comprehended in an all-encompassing way (totalized) or continuous also, if the flow rate information is required without physical contact or locally.
If without physical contact, should the dissemination of data be digital, analog, or shared? If the transmission is shared, what is the minimum frequency of data updates? As soon as you answered these questions, an analysis of the flow characteristics and properties of the working fluid, and of the piping that’ll, for the most part, hold the flow sensor, must materialize.
Flow and Fluid Quality
The fluid and its characteristics including its temperature, viscosity, pressure, the vapor pressure at extreme temperature, allowable pressure drop, conductivity, and density are itemized, along with a guide and steps of how these characteristics might act or differ. Moreover, all toxicity info and safety info must be given, along with the complete information on the composition of the fluid, the existence of air pockets, solids, likelihood to coat, and qualities of the light transmission.
Temperature Ranges and Pressure Ranges
Forecasted maximum and minimum temperature and pressure ranges must be, for the most part, provided along with its typical operating range when choosing or picking out flow meters. Whether flow can, more often than not, move backward, whether it doesn’t fill the pipe all the time or consistently, whether slug flow can arise, whether pulsation or aeration is probable, whether unforeseen temp changes can arise, or whether particular provisions are required during calibration and maintenance, this information, too, must be outlined.
With regards to the installation, think about the direction of the piping, material, accessibility, size, flange-pressure, upstream or downstream flow, schedule, regulators, valves, and gettable straight-pipe lengths. The designated engineer should determine if magnetic fields or vibration fields are, for the most part, existing in the area or possible.
Also, if pneumatic power or electric power is accessible if the location is categorized for bomb hazards. Or if other requirements, for example, the act of complying with sanitary regulations.
Repeatability vs. Accuracy
If, for example, adequate metering performance can be, for the most part, acquired from two different flow sensor classification and one flow meter has parts in motion, choose the flow meter without parts in motion. Parts in motion are an inherent source of dilemmas, not only because of the apparent reasons of susceptibility to coating, wear and tear, and lubrication, but also because parts in motion need clear spaces for the flow to be calculated.
All the more with well-calibrated and maintained flow sensors, the unmeasured flow differs with changes in temperature and viscosity. These changes also alter the internal dimensions of the flow sensor and might need compensation.
Moreover, if you can get the same metering performance from both a point sensor and a full flow indicator, it's best to utilize the flow meter. Since point sensors don't measure the entire flow, they precisely measure if it's placed to a profundity where the flow velocity is the mean of the velocity profile all over the pipe. Although this point is identified at the time of flow meter calibration, it rarely stays unchanged, because velocity profiles alter with factors such as temperature, flow rate, viscosity, and so on.
There are plenty of flow meter types available in the market today, for example, open channel flow meters, variable area flow meters, and mass flow meters. Whatever you choose to get, make sure to consider the application where it will be used. With that knowledge, you can choose the right flow meter in no time. Be sure to research and understand each flow meter type so that you won’t waste your money, time, and effort. Aside from this article, you can talk to any application engineers if you have any questions about flow meters.