Patent ID: 7100629

Claim:
A method of converting a normally open balanced valve to a normally closed balance valve using the same valve body, said valve body comprised of an inlet port and an outlet port, said valve body further comprising a first side and a second side, said first side and said second sides each provided with apertures, said valve comprising a portion extending between said first side and said second side for dividing the valve into an inlet chamber and an outlet chamber, said valve provided with a plug provided in a position such that an opening between the inlet chamber and the outlet chamber is normally open, said plug having a first side and a second side provided with a pressure port allowing fluid to flow from said second side of said plug side of said plug to said second side of said plug into a pressure chamber provided in said valve such that fluid flows from said inlet chamber through said port into said pressure chamber to balance the fluid pressure on said plug, and a stem connected to said first side of said plug: the method comprising; removing a first bonnet assembly from the aperture of first side of the valve; removing a stem and plug assembly from the valve body through the aperture in the first side of the valve; said plug provided with a port allowing fluid to flow from one side of the plug to the other; removing a first cap provided to cover the aperture in the second side of said valve; removing the stem from the first side of the plug, and connecting it to the second side of the plug; inserting the connected stem and plug into the valve assembly so that the plug is positioned to close of the flow of fluid from the inlet chamber to the outlet chamber when the plug is in its normal position; covering the aperture in the second side of the valve with a second cap assembly; and covering the aperture in the first side of the valve with a second bonnet assembly, wherein a pressure chamber is created between said plug and said bonnet, and wherein fluid flows from said inlet pressure chamber through said port in said plug into said pressure chamber to balance the pressure on said plug from fluid in said first chamber.