There are various sorts of gate valves used in numerous applications across a wide range of pipeline and workplace types. Below, we have listed some of the most popular types of gate valves on sale in the UK and elsewhere, with a brief description of each kind.
Wedge Gate Valves
A wedge gate valve is one of the more common types you will find in widespread use across all relevant plumbing and industrial pipeline setups. Subtypes include the solid wedge, the flexible wedge, and the split wedge.
Solid wedge gate valves (or plain wedge valves) tend to be the most widely used. They are often among the simplest and cheapest options but offer good mechanical strength. They are broadly suitable for nearly all types of fluid media. Their robust, single-piece construction makes them especially appropriate for use in pipelines with turbulent fluid flow.
In wedge valves, the barrier or gate is slightly inclined against the flow path of pressurised liquid in the pipe. For this reason, they are also referred to as tapered gates. This angle creates a wedging force as the valve closes, and helps to make for a more reliable seal at higher fluid pressure ratings.
Split Gate Valves
A split gate valve, or split wedge gate valve, is a type of wedge valve in which the wedge disk itself is made from two solid pieces, held in place by a spacer or spring. This gives it the ability to self-adjust to the seats, providing added flexibility and making it easier to achieve a tighter seal with less risk of sticking or binding. They are particularly suitable for use with non-condensing gases and corrosive liquids.
Parallel Gate Valves
A parallel gate valve (sometimes called a parallel disk gate valve, or parallel slide gate valve) operates in much the same way as a wedge gate valve, but the gate features two disks placed at a 90-degree angle to the fluid flow direction. They are generally seen as safer in high temperature applications, where the parallel design is less likely to result in thermal binding.
Knife Gate Valves
A knife gate valve is a well-known type that is designed primarily for use with very thick or viscous fluids, such as slurry or powder-carrying liquid. The disks in the knife gate valve model are tapered (effectively sharpened, hence knife valves) at one end to enable them to cut and move through thicker media more easily when closing.
Flanged Gate Valves
A flanged gate valve is one where the body of the valve is flanged and bolted to the bonnet (the part on top of the valve through which the handwheel assembly connects, and which gives access to the moving parts of the valve). This tends to make them better suited to higher pressure applications than screwed connections, but less ideal than specialist pressure sealing models.