A knife gate valve is a device that regulates the flow of any liquid by opening, closing or partially opening, to control the pressure. It is regulated by a rectangular or round gate, obstructing the liquid flow when closed. If you want to install a knife gate valve, this article will make your life much easier, by giving you a step-by-step tutorial on how the job can be done systematically.
Step 1: Removing the Previous Valve
Before you do anything, you need to ensure that all operating pipe lines leading to the valve are completely shut. Precaution is as important as the task at hand. If you are installing a valve for the first time, you can simply move to step 2.
The valve is bolted to the piping through a flange joint. Use a proper sized crescent wrench or pliers, and loosen the nuts of the flange on both sides of the pipe, to loosen the valve so that it can be taken off.
You do not have to dislocate the handle, or the top stem situated below the handle, since the whole unit will be taken off once the nuts are completely free from the piping.
Note: While completing this procedure, take care of your hands by wearing gloves at all times.
Step 2: Inspection
Before you install the valve, you need to inspect both the valve and the pipeline. Make sure that both are free from foreign material that could block either of the 2 devices, and see if they are damaged in any way, since this will cause a leakage in the future. This step is important, in avoiding future complications. You need to pay close attention to the interior of the valve - it should be clean.
Step 3: Fitting the New Valve
Use a gasket to fit between the pipe and the valve. A gasket acts like a seal between the pipe and the valve, to prevent any leakage. Once the gasket is in place, bolt the flange, using a crescent wrench or plier. Use appropriate sized bolts to secure the valve to the piping through the flange. The flange will be like a ring, with the pipe on 1 side, and the valve on the other. If you are using stainless steel bolts, lubricate threads, to prevent galling i.e. adhesive erosion, of the material. When tightening the bolts, make sure that the gasket is evenly compressed, by working from side to side. Be careful not to over-tighten the valve, since this can cause severe pressure on the unit, and on the knife gate. This will make operation of the valve difficult, along with adding undue wear and tear.
Lastly, put on the valve handle and secure it with a bolt, using your pliers.
Step 4: Final Inspection
Once the handle has been successfully installed, turn it clockwise, to see if it turns smoothly. If this is the case, turn on the water supply from the operating pipe line, and do one last inspection for leaks.