How It Works: Gate Valves

All valves are designed to stop, allow, or throttle the flow of a process fluid. Gate valves—one of the original valve designs—are ideally suited for on-off, primarily liquid, service. A gate valve functions by lifting a rectangular or circular gate out of the path of the fluid. When the valve is fully open, forged steel gate valves are full bore, meaning there is nothing to obstruct the flow because the gate and pipeline diameter have the same opening. This bore diameter also determines the valve size. An advantage of this fullbore design is very low friction loss, which saves energy and reduces total cost of ownership.Gate valves are designed with a sealing unit to provide a tight seal around the stem. Our patented single loaded-spring (SLS) stem seal design, used in thread and socket gate valve and WKM Pow-R-Seal double expanding gate valves, provides superior leak protection and a self-adjusting seal designed to reduce maintenance.

Applications

Because of the diversity of construction materials, trim offerings, and design combinations available with pressure sealing gate valves, they are appropriate for a wide variety of applications. From high-temperature coking units to food and pharmaceutical services, gate valves can be trusted to reliably perform.The research presented was conducted to quantify the effects of butterfly and forged flange gate valves located upstream water meters with diameters larger than 50 mm. Errors caused by these valves can have an enormous financial impact taking into consideration that a small percentage of variation in the error of a large meter is typically related to a significant volume of water. The uncertainty on the economic impact that a valve installed upstream of a medium size water meter leads to many water utilities to oversize the meter chambers in order to mitigate the potential negative errors. Most manufacturers approve their meters for a specific flow disturbance sensitivity class according to the standard ISO 4064-1:2018. Under this classification, a correct operation of the meters requires a certain length of straight section of pipe upstream the meter. However, this classification of the meters cannot consider all types of flow perturbances. For this study, two types of valves, butterfly and gate, were tested upstream ten brand-new water meters from six different manufacturers constructed in four different metering technologies: single-jet, Woltmann, electromagnetic and ultrasonic. In each meter unit was tested at five flow rates, from minimum to the overload flow rates. The tests were conducted with valves set in different orientations, closing degrees, and upstream distances from the water meters under study. The research shows that the valves used can produce significant deviations in the measuring errors with respect the errors found for undistorted working conditions.One of the primary advantages afforded by using gate valves is that the pressure which drops can be very low when forged steel globe valves are fully open. While they are useful as on/off valves, they can also equally competent at performing bi-directional action. However, gate valves do require a large force to operate. Larger sized gate valves even require automatic actuators to operate. Gate valves are also not the quickest valve type to open or close. They also not the best suited for space-sensitive applications as they tend to take up more space compared to other valve types. In some cases, gate valves can also be prone to thermal expansion and shrinking when exposed to high-temperature fluctuations. As a result, this may provide applications with unwanted leakage.

Buy gate and knife gate valves from BM Engineering Supplies

As an established and trusted valve distributor to the Scottish process industry, BM Engineering Supplies stocks a comprehensive range of both thread and socket globe valves and knife gate valves. For gate valves, BM Engineering is the Scottish partner for one of the UK’s market-leading valve wholesaler, Leengate Valves. Their range of gate valves is approved to ISO 9001 standards and other relevant industry governing bodies. While for knife gate valves, BM Engineering partners with Orbinox UK, one of the world’s leading manufacturers of knife gate valves.