29 Nov

Installation Guidelines for a Check Valve

installation-guidelines-for-a-check-valve   Check valves are simple devices that allow fluid media (gas, liquid or solids such as sand or slurry) to flow only one way. Typical check valve installations are found in industrial plants, automobiles, plumbing and ventilation systems. Usually, check valve are relatively inexpensive, compared to more accurate control valves. For a given application, the valve body must be able to contain the media and pressure, and the gate action must have a durable service life. Installing check valves is a matter of determining the correct flow direction for the media and ensuring proper fittings for the inlet and outlet port.

Materials
Installing the correct check valve for a particular process means knowing the media the valve will control. Caustic or abrasive media (lime slurries, acids, cement mixes, etc.) require a check valve resistant to severe corrosion; stainless steel or ceramic check valves work well for such applications. A check valve installed to control hot water flow in a plumbing installation can be made from PVC plastic, brass or steel. As long as the valve can handle the heat and pressure of a standard water line, it will work well.

Installation
Installing a check valve is similar in procedure to installing any other valve with one important distinction: direction. The valve must be installed in the media’s flow direction–nothing can move against a closed check valve gate. Check valve manufacturers include on the valve body an arrow indicating proper flow direction.

Incoming and outgoing lines can be connected using clamps, swage fittings (fittings using a collar around the line, with the fitting and the valve stem hydraulically compressed together) or threaded fittings.

Access
Check valves work automatically to eliminate back flow in a process line. There’s no need for manual operation–the valve can be installed in relatively inaccessible locations. Although other valve installations may require clearance for actuators, access to a manual valve shut off or other features, check valves require little maintenance.

If installed as a diversion valve to relieve excess pressure or heat, the check valve gate can be adjusted to respond to specific pressure settings. For example, a check valve can prevent a steam boiler from building up too much pressure or a car’s radiator from rupturing when the coolant fails: the check valve will divert the high pressure media away from the process and avoid catastrophic failure. When pressure and heat amounts remain within operating limits, the check valve will stay closed.

 

Sourced by ekomeri.com

03 Nov

What is a Plug Valve?

what-is-a-plug-valve

A plug valve is a simple type of valve that allows or blocks the flow of a liquid through a pipe. The plug itself is often shaped like an upside-down ice cream cone or a cylinder. A handle on top allows the user to turn the plug valve so it rotates and stops or starts the flow of liquid. A minimum of two holes, known as ports, must exist in the plug for liquid to flow. The ports are located on opposite sides of the plug, and when the plug is turned to the open position it creates a passage for the liquid to flow through.

This arrangement of two ports is known as a 2-port valve. The pipe in which the plug valve is installed has an area for liquid to flow in and another for liquid to flow out. When the 2-port plug valve is turned on, the ports line up with the holes in the pipe and the liquid flows straight through as if the plug valve was not there. Other, more complex plug valves known as 3-way valves allow liquid to flow to a combination of different ports. One port may connect to either of the opposite two ports, or all three may connect at once.

Two major categories of vales exist: stop valves and check valves. Stop valves follow a basic design structure to turn the flow of liquid on and off, or allow partial flow. Check valves, in contrast, allow liquid to travel only one way and often do not have a handle. Plug valves fall into the stop valve category.

Other stop valve types include gate valves and ball valves. Though similar to plug valves, the shape of the parts and how they work to stop the flow of liquid typically determines the specific group they belong to. Regardless of group, stop valves typically control liquid through the use of a handle.

Operation of a plug valve is simple, making it a common valve choice. The user twists the handle and the ports are moved away from the opening in the pipe. In certain valves, a full turn is not required. Quarter-turn valves, for example, only require the user to make a short, quarter turn to stop the flow of liquid. Often, plug valves can lessen the flow without turning off completely if the user turns the valve half-closed but leaves it open wide enough for some liquid to make it through the ports.

Souced by ekomeri.com