In this article, PIF spoke to leading Scottish valve distributors, BM Engineering Supplies, to research the similarities and differences between gate valves and knife gate valves. Although these shut-off valves are generally used in on/off applications involving viscous fluids, there are numerous noteworthy design variances to contemplate when deciding which can be best suited your process application. Here, we squeeze two eyeball to eyeball to see which valve type is much better.
Gate valves such as stainless steel ball valve open by lifting a round or rectangle-shaped gate out of your path of fluids. The sealing surface found involving the gate as well as the seats is planar. As such, gate valves can be used every time a straight distinctive line of flow of fluids is necessary with minimum restriction. This popular shut-off valve type carries a flat fate closure which slides in and out, or up or down between two parallel plates to open up and close the valve. With this in mind, gate valves tend to be used for shut-off operations in contrast to flow regulation operations as on or off include the only two settings available.
Solid wedges, flexible wedges, and split wedges are found in valves having inclined seats. Parallel disks are employed in valves having parallel seats.
Regardless with the style of wedge or disk used, the disk is often replaceable. In services where solids or high velocity might result in rapid erosion in the seat or disk, these elements should have a superior surface hardness and must have replacement seats together with disks.
If the seats will not be replaceable, seat damage requires removal on the valve on the line for refacing with the seat, or refacing with the seat set up. Valves being utilised in corrosion service should normally be specified with replaceable seats.
The solid, or single wedge gate valve is among the most widely used along with the lowest cost used-type along the way industry. The purpose in the wedge shape is usually to introduce a higher supplementary seating load. Solid-Wedge Gate Valve could be installed in any position, well suited for almost all fluids and practical for turbulent flow services.
In some situations, the valve can't be reopened till the system temperature reheats the valve; this phenomenon is recognized as “Thermal blinding”.
