Why use a ball valve versus a gate valve?

Ball and gate valves essentially perform the same function. However, their structural qualities are markedly different. Ball valves have a stem and ball, which turns horizontally, and are commonly referred to as “rotational” valves. They are best suited to applications requiring on/off control without pressure drop.

Gate valves open by lifting a round or rectangular gate (or wedge) out of the path of the fluid. The sealing surfaces between the gate and seats are planar, so gate valves are often used when a straight-line flow of fluid and minimum restriction is needed.

Ball valves are designed with a ball inside the valve. A ball valve is a form of quarter-turn valve which uses a hollow, perforated and pivoting ball (called a “floating ball”) to control flow through it. It is open when the ball’s hole is in line with the flow and closed when it is pivoted 90-degrees by the valve handle. The handle lies flat in alignment with the flow when open, and is perpendicular to it when closed, making for easy visual confirmation of the valve’s status.

Ball valves are durable, performing well after many cycles, and reliable, closing securely even after long periods of disuse. These qualities make them an excellent choice for shutoff applications, where they are often preferred to gates and globe valves. That said, they do lack fine control in throttling applications.

Although ball valves tend to cost slightly more than gate valves of comparable quality, the minimal saving is not worth the potential issues that are likely to follow. Moreover, ball valves seal much tighter – and are therefore much less prone to leaks – than gate valves because of their 100 per cent shut off characteristics. Ball valves offer greater longevity, a lower rate of failure, and are easier to use than gate valves.

BME stock a wide range of ball valves, from quarter-inch to six-inch at our works in Bishopbriggs. From general purpose two-piece ball valves, v-ball control valves, hygienic valves, to heavy duty ball valves for steam; we have a variety of sizes, end connections and materials to suit many applications. We also stock gate valves up to six-inch in size, and can supply many size and material variants, including knife gate valves, on a next-day basis.