Do ball valves have plastic?

Although ball valves have traditionally been manufactured from brass, a growing number of our customers are choosing a polypropylene ball valve or PVC ball valve instead. Often cheaper than the brass alternative, a plastic ball valve can still provide excellent longevity and are built to last.

Why do non-return valves fail?

This is a common problem in many old systems where valves are generally not spring-loaded or motor-operated. In short, the non-return valve closure (during pump operation changeover), resulting in the water hammer in the pipe line, is likely to be the main root cause of the pump’s frequent failure.

Is a ball valve non-return?

Closure device that can be automatic or manual, allows only one direction of the flow; in the pumps is used to prevent the flow of the liquid to exit the pipes after the pump is switched off.

Do ball valves have seals?

The ball is supported and sealed by the ball valve seat (5) and their are o-rings (2) around the valve stem. All are inside the valve housing (3). When the valve stem is turned a quarter-turn the bore is either open to the flow allowing media to flow through or closed to prevent media flow.

What material is used for ball valves?

Common ball valve materials include brass, bronze, copper, cast iron, ductile iron, stainless and other steel types, metal alloys and plastics including PVC and CPVC.

How does a ball valve seal?

Floating ball valves are attached only to the stem, not held in place by a trunnion. This sometimes causes the ball to float slightly downstream, which then causes the ball to press against the seat, creating a positive seal. When the valve is closed, the core is wedged against the seat, ensuring positive shutoff.

How can you inhibit corrosion of ball valve by proper design?

Adding a small amount of sodium nitrite to water will prevent the valve from being corroded by the water. The asbestos filler contains chloride, which is highly corrosive to the stem of the valve.

What is a stainless steel backwater valve?

For more durability than plastic barbed check valves, these have a stainless steel body. Weld to unthreaded metal pipe. Also known as backwater valves, these valves prevent backflow of sewage and wastewater in drain, waste, and vent systems.

What are the characteristics of a plastic pressure relief valve?

At 1 1/2″ long or less, these valves fit in confined spaces. Plastic provides a lightweight alternative to metal. The heat -resistant rubber seal withstands temperatures up to 500° F. With few moving parts to wear out, these valves withstand frequent opening and closing, pulsating flow, and rapid flow reversal.

How much pressure can a plastic check valve withstand?

Rated for up to twice the pressure of standard check valves, these can withstand pressures up to 2, 000 psi. At 1 1/2″ long or less, these valves fit in confined spaces. Plastic provides a lightweight alternative to metal. The heat -resistant rubber seal withstands temperatures up to 500° F.