Being able to measure flow accurately is extremely important to many applications – this is especially true in industrial plants, where it can make a genuine difference to a company’s ability to make a profit. Lacking an understanding of flow can lead to issues not being corrected and the will impact an organisation’s bottom line. To measure flow, you need an instrument known as a flow meter. These devices are mused to measure either the volumetric or mass flow rate, or the amount of fluid passing through a pipe. Flow meters are used in a variety of different applications in measuring their volumetric flowrate or their mess flowrate. The actual application defines the type of capacity of the flow meter; both liquids and gases are measured in terms of volumetric and mass flowrate. There are actually many different types of flow meter, and the one that you need depends entirely on the application that you want to use it for. In this article we take a look at five of the common types of flow meter to understand their applications. Differential pressure flow meter One of the more common forms of flow meter found in applications around the world, differential pressure flow meters are often used in the oil and gas industries. They also have applications in everything from HVAC and pharmaceuticals to mining, paper and chemical production – their uses are clearly extremely wide. These meters measure the differential pressure across an orifice where the flow is related directly to the square root of the differential pressure that is being produced. The meters work with two elements: primary and secondary. The primary element produces a change in kinetic energy either through a flow nozzle, an orifice plate or a venturi flow meter. The secondary element is used to measure the differential pressure and then provide the signal. Positive displacement flow meter Positive displacement (PD) flow meters are well known for being extremely accurate. This means that they have a range of uses in the transferring of oil and other fluids such as gasoline and hydraulic fluid. They even have use around the house with applications in water and gas. PD flow meters are used to measure a volume filled with fluid, deliver it and then fill it again. This allows the meter to calculate the amount of fluid that has been transferred. The majority of forms of flow meter measure some sort of parameter and convert the value into a flowrate – PD flow meters actually measures the flow of the fluid. Some of the meters include piston meters, nutating disk metres and rotary vane type meters.   Velocity flow meter Another common form of flow meter is the velocity flow meter. These instruments are used to measure the velocity of the stream in order to calculate the volumetric flowrate. Velocity flow meters are less sensitive when the Reynolds number of the fluid is higher than 10,000. Some examples of velocity flow meters include electromagnetic and sonic/ultrasonic, turbine, paddlewheel and vortex shedding flow meters. Mass flow meter Mass flow meters measure the force resulting from mass accelerating through a pipe, this means that they are most effective in mass-related processes. They work by measuring the force of mass moving per a unit of time, rather than volume per a unit of time. Common forms of mass flow meters include thermal dispersion meters and Coriolis mass meters. Many of the major applications for mass flow meters are related to chemical processes. They are often found in the gas and chemical industries, as well as throughout power, pharmaceuticals, waste water and mining. Open channel flow meter Finally, we come to the measurement of liquid in open channels. This occurs in v-notch, weirds and flumes. They allow for a concentrated or a limited free-flow of liquid depending on the shape of the structure. Some of the most common applications for open channel flow meters include measuring free-flowing liquids such as those found in rivers, streams or sewers. Image courtesy of: Applications Engineering

A number of multi-million pound contracts has been awarded by Network Rail in Scotland and the North East. Totaling £467 million, the contracts were handed over under two Control Period 6 frameworks. Valued at £320 million, the most significant contract for a renewals and enhancements framework went to BAM Nuttall. The contractor will replace and refurbish structures across the rail route, as well deliver improvements at stations. Meanwhile, two Geotech frameworks worth a combined £147 million have been awarded to Story Contracting (London North East) and QTS (Scotland) as part of the procurement process. “We are exceptionally proud of the collaborative work QTS has carried out during the last control period, with some outstanding geotechnical projects delivered across Scotland. It is a testament to the hard work of our team during the CP5 contract, and the strong relationship that we have built with Network Rail, that has allowed us to be successful in this CP6 tender process,” said Alan McLeish, QTS Managing Directo. “Our expertise and commitment to finding further efficiencies for Network Rail by using innovative plant and methods, stands us in excellent stead to continue providing a high standard of work over the next five years,” he added. In addition, five-year contracts have also been awarded, with an option of two-year extensions on the Geotech framework. “Work to renew our infrastructure is increasingly important to improve reliability for our passengers, and making sure we have the right suppliers to deliver those improvements is paramount. We look forward to working closely with our supply chain to build on the progress that has already been made and ultimately, build a better railway for our customers,” commented Kris Kinnear, Interim Regional Director for SNE. The latest contract awards complete the procurement activity for Scotland and North East, which is anticipated to hold one of the largest work-banks for the coming five-year funding period.

As part of Yorkshire Water’s “big goal” for the environment, more than 14,000 trees were planted at Ogden Water last month, aiming to create new “green infrastructure”. One million trees will be planted in total on land owned by Yorkshire Water and leased by the Woodland Trust to enhance the environment and reduce the risk of flooding. “We made a commitment in January 2018 to plant one million trees in the county over the next ten years to help reduce flood risk, capture carbon and boost woodland wildlife opportunities. I am thrilled to see trees being planted at Ogden as part of our commitment to tree planting within the new Northern Forest,” commented on the scheme Yorkshire Water’s catchment and recreation manager Geoff Lomas. The partnership between the water company, the Woodland Trust and the Forest of Bradford will help expand the White Rose Forest as part of the new Northern Forest project. A mixture of native trees and shrubs including oak, beech and silver birch will be planted to enhance the biodiversity of the site while protecting its archaeology and retaining public access. The scheme received backing from the prime minister, Theresa May and environment secretary Michael Gove in 2018, and over the next 25 years the Northern Forest will see the planting of more than 50 million trees from Liverpool to Hull, the first of its kind for more than a quarter of a century. “The launch of this ambitious project at Ogden Water is a huge milestone for Calderdale and will have far-reaching benefits for future generations to come. With the Calder Valley being a flood-prone catchment, we truly value this programme of work not only for its benefits for ecology, biodiversity and air quality but also as a complementary measure to support traditional engineered flood defences,” said Councillor Barry Collins of Calderdale Council. Spanning more than 120 miles between the cities of Hull, Leeds, Manchester and Liverpool, the proposed Northern Forest will help boost habitats for woodland birds and bats and protect species such as the red squirrel.