Technical Bulletins

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Tuesday, 23 April 2013 07:18

Aquatherm Valve Applications

Aquathem offers a variety of valves in our catalog. These valves range in offering between the screw-down stop globe valve, concealed valves, inclined globe valves and ball valves.

This document (available as a PDF here: 201304A-AQTTB-Valve-Applications.pdf) is an attempt to identify the valve offerings and their different applications.

Globe Valves

Globe valves are named for their spherical body shape with the two halves of the body being separated by a baffle (see Figure 1) consisting of a movable disc-type element and a stationary seat. Typically the body of the globe valve is spherical in shape, hence the name Globe valve. Aquatherm's globe valves do not have a spherical body.

1

Figure 1: Globe Valve

Globe valves, due to their internal design, are used mainly for flow control. They operate fairly efficiently in a partially open position to throttle or control the flow rate of liquids. They are used to control flow rates when mixing fluids or in batching operations where fluids may need to be continuously adjusted. Globe valves can be operated manually or by an actuator.1

Advantages: Can be fast acting; Precise Control; Can be used in high-pressure systems.

Disadvantages: High head loss; Large opening for disk assembly; low coefficient of flow; Not good for clean or sterile applications; Valve stem requires many turns to open or close.

Aquatherm offers globe valves in straight and inclined or "Y" globe versions.

valve 1

valve 2

valve 3

Y-body design valves, also known as cross-flow globe valves, derive linear action from the incline between the axis of the inlet and the outlet ports. This design reduces the high pressure drop inherent in globe valves. The seat and stem are at a 45° angle with the media flow, for a straighter flow path at full opening. The Y-design also keeps the stem, bonnet and packing in a relatively pressure resistant envelope. This valve design is well suited for high pressures and other severe services.2

2

Figure 2: Y-Body Globe Valve