Heating Helper

CHAPTER 8 - VALVES: TYPES AND APPLICATIONSGate Valve has a wedge-shapeddisc that is raised to open and loweredto close the valve. It is usedeither fully open or totally closedand is not designed for throttling.Ball Valve its operating deviceconsists of a ball with a hole throughits center. The valve operator rotates90 degrees from fully open tothe fully closed position. Its majorapplication is isolation but can beused to regulate flow.Globe Valve uses a round disc ortapered plug-type disc that seatsagainst a port to close the valve.Globe valves are used wherethrottling and/or when frequentoperation is required.Butterfly Valve has a wafershapedbody with a thin, rotatingdisc closing device. Like the ballvalve, the butterfly operates witha one-quarter turn to go full opento closed. The disc is always in theflow but the disc is thin and offerslittle flow restriction.Angle Valve operates the same asglobe valve. Has less resistance toflow than its globe counterpart andby design acts as a 90° elbow, eliminationgthe need for a fitting.Swing Check Valve has a hingeddisc that swings on a hinge pin.When the flow reverses, the pressurepushes the disc against a seatpreventing back flow.77