A butterfly valve is a quarter turn valve that gets its name from the way it moves. Butterfly valves are placed inside tubes or pipes. They are used to regulate the flow of any material that passes through the tube. This type of valve consists of a metal disc that has been mounted onto a rod. The disc pivots back and forth, which makes it appear like butterfly wings flapping.
When a butterfly valve is in the open position, the disc has made a quarter turn past its original position. This allows for an unobstructed flow of the material in the pipe or tube. When the valve is in the closed position, the disc fully blocks the passageway and isolates the material in the pipe.
Butterfly valves are installed inside tubes or pipes between each section. The disk fills the round shape of the pipe or tube. There is a lever located on the outside of the butterfly valve. The placement of the valve into the opened or closed position is adjusted with this mechanism. Butterfly valves come in various styles and sizes. The pressure ratings vary as well.
Installing a butterfly valve is easy once you know the basic steps involved. The first step is to clean all the equipment you will be using. Clear away any dust, dirt, oils or other substances. This will ensure there is nothing impeding the function of the valve, pipe, gaskets or flanges. Open up the valve and wipe off the disc edges. You will install the valve in the closed position, so close it when you are done cleaning it.
Place the flanges or rims of the valve on the sides of the pipe or tube. These collars form seals and allow you to connect the valve to the smooth pipe surface. The style of the flanges varies from valve to valve. Once the flanges are mounted to the pipe, tighten them slowly. The tension you create will seal the bond between the valve and the pipe.
Slide the butterfly valve between the rims on the pipe. Avoid damaging the gasket that seals the valve and flange surfaces. Make sure the bolts are matched to the holes prior to tightening them. To create an even amount of tension, tighten the bolts in a crisscross direction. Open the butterfly valve to ensure there is enough room for it to move in the pipe.