Basic Choosing the Right Valve

What's So Important About Choosing the Right Valve?

Valves have long been more than just a simple device for turning on and shutting off flow. Valve design has kept in step with industrial progress - the development of piping techniques, and the ever-growing list of fluids for processing, power, and finished product.

Progress in valve design puts at the piping engineer's elbow a great variety of valve types, each with some special qualification for service. From these he may choose the right one to provide dependable and economical performance in each particular need.

It's a case of carefully matching up the valve's service characteristics with the service requirements. It's a matter of knowing every detail of the job to be done - working pressure, temperature, fluid, volume of flow, corrosive elements, valve operating cycle, etc. Other equally vital considerations are the original valve cost, installation cost, and, of course, the cost of maintenance.

Principal Valve Types

Gate Valve

Commonly used in industrial piping, this type of valve, as a rule, should be used as a stop valve...to turn on and shut off the flow, as opposed to regulating flow. It gets its name from the gate-like disc which operates at a right angle to the path of flow.

Globe and Angle Valves

The flow through globe valves follow a changing course, thereby causing increased resistance to flow and considerable pressure drop. Because of the seating arrangements, globe valves are the most suitable for throttling flow. The valve is named after its globular body.

Angle valves, similar in principle and a companion line to the globe, are designed to permit a 90 degree turn in piping and are less resistant to flow.

Check Valve

Sometimes referred to as the non-return valve, the check valve stops backflow in the piping. Unlike the gate and globe valves, this simplest of types operates automatically.

Ball Valve

Unique in design, this valve controls the flow of a wide variety of fluids. It can be opened or closed in a quarter-turn of the operating handle. The name "ball" is derived from the ball-shaped disc located within the body. A hole through the center of this disc provides the straight-through flow which is characteristic of ball valves. Light and durable, these are the valves that are playing increasingly important roles in our nation's missile projects, as well as in industry and commercial buildings.

Butterfly Valve

Here's a valve that is extremely durable, efficient and reliable. The butterfly valve derives its name from the wing-like action of the disc which operates at right angles to the flow. Its chief advantage is a seating surface which is not critical. The reason for this being the disc impinges against a resilient liner to provide bubble tightness with low operating torque.