Gate valves are used for On-Off control whereas Globe valves in addition can also be used for the flow regulation.Gate valves of the same size are cheaper than globe valves.Gate valves because of their design have very little fluid trapping in the line but the globe valves have a larger amount due to the direction of flow.
Gate valves offer very little resistance to fluid flow in fully open position and also have small pressure drop across the valve. Globe valves on the other hand have a high pressure drop even in fully open conditions and offer substantial resistance to fluid flow.
Gate valves are unidirectional and can be put around in any way. The globe valves are not.Both flow valves,Globe valve and gate valve have similar external housing but operational functions of both differ little.
The main difference between globe and gate valve is in the form of the inner elements and the form of the flow inside the both valves. Globe valve has very good throttling ability while gate valve is not used for throttling.Gate valve is best suited for isolation and globe valve is best suited for regulating or throttling the flow.
Globe Valves:
- Globe valves vs gate valves are designed for many applications in several fields, including the oil and gas industry. However, each valve doesn’t serve the same function.
- Globe valves are generally used to stop, start, and regulate flow within a pipe. They’re made with a spherical body and a disc. The disc within the globe valve is designed to move up and down from the seat. These vertical movements allow the space between the disc and the seat to change slowly when the valve starts to close. This gives the valve good throttling ability and allows it to regulate flow within a pipeline.
- The flow rate of a globe valve depends on the space between the disc and the seat. The further apart they are, the more liquid that will flow through the valve.
- Globe valves are also designed with a stem connected to the bonnet right above the disc to maintain a tight seal when the valve is fully closed. Because of that, globe valves are less likely to experience seat leakage compared to other valves.
- These valves can double as control valves and are commonly used for corrosive, highly viscous media as well as high-pressure and high-temperature systems.
- Globe valves cannot seal tight as compared to gate valve.Gate valve has tight shut-off ability in pipe lines.Because of this tight shut-off ability of gate valve,it is used upstream of globe valve.
- You might have seen this gate and globe valve combination at the discharge pipe of pumps.Globe valve requires greater torque to operate as compared to gate valve.
- This greater power requirement for globe valve is also considered when designing automatic and motor operated actuators for valves.In a globe valve, the closure element is usually called a “poppet”, and it travels perpendicular to the plane of the seat.
- The globe valve can be repaired in place while nearly all gate valves need to be removed from the piping system to have leakage problems repaired.
A globe valve can be opened against a high differential pressure, while a gate valve will bind and cannot be opened. If you try to open against a high DP, the seat will score and leak. - A globe valve has a near linear characteristics of CV vs. % open, while a gate valve has a severe parabolic characteristic and thus cannot be used for throttling.
Gate Valves:
- Gate valves are used in plants in the oil and gas industry as well. However, they’re designed only to start and stop flow within a piping system. They, unfortunately, won’t regulate flow.
- Gate valves are also designed differently than globe valves. Instead of a disc, these valves have gate faces that are parallel or wedge shaped, and they’re designed with a rising or a non-rising stem. This helps workers understand when the valve is fully open or fully closed.
- These valves are also known to have lower pressure drops and offer little resistance to fluid flow, especially in the fully open position. Most importantly, gate valves can be set in any directional flow. Globe valves, on the other hand, can’t.
- Gate Valve is not designed to regulate flow ,and if done so then we observe noise ,vibration and seat / disk damage in gate valves. While globe valve can be sometimes used for stop start of flow in case of unavailability of gate valve.Gate valve is generally used for isolation.
- Gate valve can be used in both directions as designs are available for both directions of flow.Same gate valve can have flow in both directions.While globe valve has flow direction usually indicated on it and is used in compliance with that.
- Valve Opening and closing geometry of disk and seat is also a difference between globe and gate valve.
- In a gate valve, the closure element is a plate or disk which travels parallel to the plane of the seat. The gate in a dam is a well known example.