Rame Gate Valve
4″ Gate Valve
Gate valve 4 inch, generally gate valve work by inserting a rectangular gate or wedge into the path of a flowing fluid. They are operated by a threaded stem which connects the actuator (generally a hand wheel or motor) to the stem of the gate. If the valve has a rising stem its position can be seen just by looking at the position of the stem.
When fully open, a gate valve has no obstruction in the flow path and so has a very low pressure drop. If the fluid is very viscous a special type of gate valve known as a knife gate valve can be used.
One reason that gate valves are not normally used to regulate flow is that the flow rate of the fluid is not proportional to the amount that the valve is open. Moreover, a partially open gate valve may suffer from vibration.
Gate valve are characterized by a “gate” that closes in a plane perpendicular to the flow of fluid. They are used primarily for on/off, nonthrottling service. Shearing of high-velocity flow will cause a partially open disk to vibrate and chatter which will damage the seating surfaces and prevent a tight seal. They are suitable for most fluids including steam, water, oil, air, and gas. Gate valve may have either a solid or flexible wedge disk. In addition to on/off service, gate valves can be used for regulating flow. Usually in sizes 6 in. and larger, but will chatter unless the disk is fully guided throughout travel.
Gate valve are mass-produced in sizes from 2” to 24” although valves up to 72” are not uncommon. Popular body materials include cast iron, cast steel and stainless steel. Cast iron lined with austenitic stainless steel is possible for sizes between 2” and 24″. Valves with fabricated steel bodies are made in sizes from 2” to 42″. Exotic alloys, such as Alloy 20, Hastelloy β™ and Hastelloy C™, are also available. Valves can be fully lined with an elastomer to reduce corrosion and erosion. These valves may have a shaped knife edge and a preferred flow direction. The gate is generally of stainless steel. The yoke is generally cast or fabricated in steel although stainless steel may be an option. A bronze bearing may be fitted.
Gate valve has pressure rating from ANSI Class 150, class 300, class 600, class 800, class 1500, class 2500, class 4500