In gate valve, a gate slides between the seats of the valve. Movement of the gate is at right angle to the flow of fluid. By opening the valve, flow path is enlarged in a highly non-linear manner with respect to percentage of opening.
Gate valve is normally used for isolation application where only fully close or fully open position is required. this valve is suitable where frequent opening and closing is required. the gate fully retracts in the bonnet. so, the pressure drops across the gate is less.
Globe valve is widely used valve in high pressure steam and water line. movement is parallel to the flow of the fluid.
Disc of the valve needs to move a small distance from its seat to get a full flow. the main advantage of this valve is that it can be used for throttling purpose and where positive shutoff is required. Globe valve is used for isolation and regulation purpose.
The external housing (shell) of gate and globe valves are similar, but the globe valve is designed to serve as a regulating valve, meaning that it can adjust the flow by the percentage of the opening. However, the gate valve is not designed to regulate flow, but to stop the flow. A gate valve should always be either fully open or fully closed.
The main difference is in the form of the inner elements and the form of the flow inside the valves. In addition, the gate valve may have a rising or non rising stem while the globe valve is typically a rising stem design. The direction of flow through a gate valve is not important. However a globe valve has a flow direction indicated on the outer shell (body) which indicates the direction of flow from beneath the seat.
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