Do you know how to measure the flow rate of your operation? Well, it might appear like a straightforward question, but the answer can be complicated and complex. Plenty of factors contribute to whether measuring or not measuring flow is nearly impossible or easy.
Factors comprise of, yet not limited to, the expected range of velocities, flow rates, an acceptable level of uncertainty, type of fluid, cleanliness, material, and size. Evaluating and checking these factors is essential before choosing and installing a measurement technology.
For a little help, we’ll walk you through the critical things to consider when choosing a measurement technology. Take a read!
The following information is a list of available measurement technologies that users can use to audit flows. Also, you can find these devices in many online stores like SmartMeasurement.
Differential Pressure Meters
These devices are the most common measurement technology used today. Differential pressure meters function on the principle that a surge in the velocity of flow is supplemented by a slump in the fluid’s pressure. The square root of the flow rate is relatively proportional to the pressure drop across the meter. Users can obtain the flow rate across these measurement technologies by calculating the differential pressure, getting its square root, and multiplying this by a meter coefficient and an area coefficient.
The following are some of the well-known DP technologies today:
– Pitot Tubes
– Elbow Meters
– Orifice Plates
– Target Meters
– Venturi Meters
This measurement technology measure the flow’s velocity, wherein when multiplied by a velocity profile and a known flow area, it can be equated to a volumetric flow rate. For velocity meters to give precise results, they should be installed in areas with uniform flow.
Take note that these meters can be either non-intrusive or intrusive. Non-intrusive meters are typically installed on the exterior of a pipe. However, in some instances, they might need the installation of conduits and sensors along the walls of the tube.
The following are some of the popular velocity meters today:
Open-Channel Control Structures
This technology can be utilized to know flow rates by computing the area of the head of the fluid bearing the flow and the stream. A straightforward and direct way of gauging flow in open-channels is using weirs.
Weirs consist of obstructions like a vertical plate situated across the open-channel with a specially-shaped opening or with a level. This interference raises the level of the water behind the weir.
So, when fluid overflows over the device, its flow rate is the depth of the water above the weir crest. The generally known weir structures are the broad-crested, v-notch, and rectangular. On the other hand, flume control constructions are sections that trigger the flow to accelerate.
Moreover, acceleration is formed by minimizing the flume’s cross-section. Thus, when the flow expedites, it traverses through the critical depth, resulting in a rare water surface profile for a specified discharge.
For this reason, it permits the use of a non-linear relationship for flow measurement. This meter varies in size from 1 inch to about 50 feet wide. Also, it can contain a wide discharge range ratio of 50:1.
Also, Weirs and Flumes provide the same accuracy level. The main difference between the two is the cost. Generally, flumes are more expensive compared to weirs.
Choosing a Measurement Technology
When selecting a measurement technology for your application, there are several things to keep in mind. The information below can be used to assess the relative pros and cons of each device and to determine whether it’s feasible for implantation or not.
The criteria listed manifest important aspects or elements to any successful flow measurement monitoring program. Take note that they’re not listed in order of prime concern.
– The technology must present or deliver an acceptable accuracy level.
– It must be made or designed to function beyond the expected range of flow rates.
– It must work effectively under any debris conditions.
– The technology, if befitting, must enable continuous flow monitoring.
– It must have minimal influence on the existing structural features.
– It must not affect the condenser cooling system operation.
– It should be proven and tested at power-generating companies.
– It doesn’t need further engineering development and is available.
– The technology should lessen obstruction and deterrent to facility operations throughout the installation of the devices.
– It should meet all safety requirements.
Essential Things to Keep In Mind
When examining or evaluating proven and tested measurement technologies at industries with different environmental, hydraulic, and physical conditions than the area under consideration, then it’d be best to determine the applicability of the device. Moreover, the available options are characterized as alternatives that supply data in ample detail to create a conceptual technology or design that has been made at similar facilities.
Also, take note that each measurement device should be qualitatively examined to know whether it offers more benefits compared to other technologies. Say, for instance, one device would be more advantageous over another technology if it needs fewer structural changes for its installation. Or if it’s just like another technology yet more precise.
Choosing a flow meter technology for particular applications can be very difficult because there are plenty of options available. This burden becomes more challenging when the user knows the multiple application variables that affect their decision. Historically, this might explain why industries have a hard time quantifying fluid flows. Ultimately, learning the principles behind each technology is quintessential.