What is a Gate Valve?

Gate valves are used in a number of industrial applications to control the flow of fluids. Used in conjunction with other flow-controlling components, gate valves are an essential element in thousands of above-ground and underground pipe systems. In this blog, we will discuss the definition, function, types, and applications of gate valves.

The most basic gate valve design consists of 3 primary components: the handwheel, stem, and gate. During routine operation, the handwheel influences the vertical position of the stem, which is attached directly to the gate. When used properly, gate valves are only meant to completely restrict the flow of fluids or allow for free passage. Making the mistake of opening the gate halfway in an attempt to control flow will result in a decreased lifespan of the system as a whole.

Different gate valves will generally all have the same functioning principle, with the biggest contrast being in the design of the smaller components. Bonnets, for example, come in several different formats, each having its own benefits. Screw-in bonnets are the most simple and widely used variations, and as the name suggests, they can screw in and out with ease while still providing a leak-proof seal. Union bonnets are held in place with a union nut, which allows for frequent inspection and maintenance of the bonnet without deteriorating the leak-proof seal over time. Finally, pressure-seal bonnets are used for high-pressure applications and are designed with a small cup inserted into the valve body. Under high fluid pressure conditions, this cup expands and creates a more robust seal.

Gates also come in various designs, with the selection based on the intended application. Wedge valves are the most universal due to their simple and easy-to-maintain design. In this configuration, two discs are permanently affixed to the pipe on both sides of the location where the gate will rest. As such, when the gate is rotated to the closed position, it will be "wedged" against the neighboring discs. This layout ensures that the gate will not rotate or come out of place during periods of high pressure. On the other hand, parallel slide gates are designed with a spring in the middle that pushes the two sides of the gates outward to create a tight seal. Additionally, since there is no wedging action, this gate type requires much less manual effort to close than its counterparts.

Another gate design is the slab gate or through-conduit gate. This unique gate design consists of a thick piece of metal with a borehole equal in diameter to the pipe. In the open position, the borehole is aligned with the rest of the pipe, allowing for a steady flow of fluid that is unobstructed by pressure changes. Such gates are commonly found in natural gas liquid and crude oil applications.

Since gate valves are relatively inexpensive, easy to install, and can be implemented under and above the ground, they are used in a myriad of industries, including oil, pharmaceuticals, manufacturing, automotive, and marine. In any case, gate valves are the most low-maintenance method of stopping the flow of media, be they liquid, gas, or solid. The only downsides to these systems are their propensity to wear over time and their reputation of being notoriously difficult to repair.

If you are looking to source high-quality gate valves from a reputable distributor, NSN Axis has you covered. At NSN Axis, we offer over 2 billion new, obsolete, and hard-to-find items which have been thoroughly vetted through our robust quality assurance program. Together with our NO CHINA Sourcing pledge, these measures allow us to operate with AS9120B, ISO 9001:2015, and FAA AC 00-56B certification and accreditation. Source your next project through NSN Axis to learn why so many customers choose us to fulfill all of their operational requirements.