What Does a Globe Valve Mean?

A globe valve regulates the flow in a pipeline. It is used to control or Globe the flow of a liquid or gas through a pipeline. A globe valve is named for its spherical shape, with the two halves of the body separated by an internal baffle.

Although these valves have a slightly higher pressure drop than gate/ball valves, they can be used in situations where valve pressure drop is not a controlling factor.

The globe valve is primarily used to Globe, start and regulate flow. It consists of a removable disc element and a fixed ring seat that is roughly spherical in shape. The seat of the globe valve is in the middle of the pipe and parallel to it, and the opening in the seat is closed by a disc or plug. The construction of a globe valve can handle flow in either direction.

The most common application for globe valves is a standard faucet. When the handle is turned, the disc is lowered or raised. When the disc is fully lowered, the water supply is shut off. When the disc is fully raised, the water flow reaches its maximum velocity. In large industrial applications, electric, pneumatic or hydraulic actuators can be used instead of manual handles to seal the globe valve.

Industrial Manual Through Stainless Steel Globe Valve

The baffle inside the globe valve allows the product to change direction to pass through the baffle. This angled movement means that the product is not free to flow and causes a pressure drop behind the valve. globe valves are not typically used for slurries or thicker materials that may be blocked by the baffle.

Due to their pressure sensitivity and corrosion potential, to avoid premature failure and to ensure satisfactory service, consideration should be given to

Flow control range

Pressure drop

Intended duty

The Forged Steel Flange Globe Valve

Applications

Globe valves are used in wastewater plants, power plants and process plants for shutting off and regulating service. They are used in steam lines, coolant circuits, lubrication systems, etc., where control of the amount of fluid passing through the valve plays an important role.

Material selection for globe valve bodies is typically cast iron or brass/bronze for low pressure applications and forged carbon steel or stainless steel for higher pressures and temperatures. The specified body material typically includes all pressurized components, while "inboard" refers to components outside the valve body, including seats, valves, and stems. Larger sizes are identified by ASME Class pressure ratings and are ordered with standard bolted or welded flanges. Sizing globe valves requires more effort than sizing some other types of valves because pressure drop through the valve can be an issue.

Open stem designs are most common in globe valves, but non-open stem valves can also be found. The bonnet is usually a bolt-on design that can be easily removed for internal inspection of the valve. The valve seat and disc are easily replaced.

Block valves typically use a pneumatic piston or diaphragm actuator acting directly on the stem to move the valve disc into place. The piston/diaphragm can be spring biased to open or close the valve with a loss of air pressure. Electric rotary actuators are also used.

Some building codes require on/off valves upstream of certain equipment, such as at the water heater inlet. Here, ball or gate valves are acceptable, while globe valves are not.

Considerations

Globe valves are primarily control valves and are ideal for automation. Many manufacturers offer integral valve and actuator assemblies for this purpose. In some cases, the valve will be equipped with a direct-acting stem actuated by a piston or diaphragm, thereby precluding the use of a conventional threaded stem. These valves typically include a manual override for manual operation of the valve. Since sizing valve actuators is an exercise in itself, these integrated valve actuator combinations can reduce some of the effort involved in specifying an automation system.