History of Gate Valves Charley Peckham was issued the first US patent for a Gate Valve. Thoughout the rest of the 1800s, many inventors patented their own design of valves to control the flow of steam. Although there were many more, most of us know the names: Crane, Lunkenheimer, Powell, and Pratt.
Early gate valves were made of brass and iron. During the early 20th century, steam pressure demand was at the 150psi and even up to 200 psi. Carbon steel valves were developed to handle the high temperature superheaters and steam turbines. Chrome/moly became a staple of the power industry.
Acids and other chemical compounds were being developed by chemical and petro-chemical companies. New alloys such as Hastelloy, Alloy 20 and Inconel were developed to handle these corrosive chemicals.
Pressure-seal bonnet gate valves were developed in the 1940s. This design reduced the mass and weight of high pressure gate valves by as much as 40%. Pressure seal valves are very commonly used in power plants.
History of Ball Valves Although ball valve roots date back to the 1800s, practical applications of ball valves may be credited to Crane Valve Company in 1945 for its soft seat design. Crane did not commercially market such a valve until later. In fact, several other companies beat them to the punch. It is not my intention to credit anyone with an invention, but to give some kind of cronological data for gate valve and ball valve introduction and history.
Basic Difference Between Gate Valves and Ball Valves Gate valves are made of metal with metal seats. High temperature is likely the best application for Gate Valves with the exception of Brass Gate Valves. Ball Valves have options for a wide variety of seats from soft seats to metal seats. Ball Valves likely fit a wider variety of applications than gate valves.
High Temperature Gate valves are intrinsically high temperature as the seats are metal. Metal and other high temperature seats are available as options with ball valves, but cost significantily more that eguivalent gate valves.
Leakage General Purpose Gate valves typically leak 3-5% through the valve. Ball valves typically have leaks rates so low that it cant be easily measured. Specially designed valves have better performance.
Cost Gate valves are lower cost than ball valve for most applications.
Weight and Spacing Originally ball valves had to have the same ANSI Face to Face Dimension as Gate Valves. Why? So if you wanted to replace a flanged gate valve with a flanged ball valve, you had to have a drop in replacement so you didnt have to cut and reweld the pipe. Recently, ball valves have been introduced that take up less space than conventional Gate Valves and Ball Valves. The new valves are called Wafer Ball Valves and are not as long, not as heavy and not as expensive as Valves designed to the ANSI Face to Face Dimension. If a valve is lighter, that also means it is easier to pull it out of service and haul it back to the maintenance shop for repair.
Height Ball Valves are typically not as tall as Gate Valves. Actuated Gate Valves can be extremely tall.
Summary Although Gate Valves have been around longer than Ball Valves and they typically cost less, you might want to consider them for you next Valve Application.
ANSI Gate Valve
ANSI Flanged Gate Valves Flanged Gate Valves were the predominant shutoff or isolation valve of choice for many commercial and industrial applications in the past and continue to be used quite frequently today. The Advantages of Gate Valves are Low Price, Commercial Acceptance and Standard High Temperature Rating of 800 Deg F. Some of issues with Gate Valves are Thru-Valve Leakage, Stem Leakage, Corrosion of Internal Parts and Multiturn Rising Stems which required overhead space that was not always available. Many of the Obstacles can be overcome, but at increased cost.
Actuated ANSI Flanged Gate Valves Gate Valves can be Actuated / Automated with either an Air Cylinder or a Linear Electric Actuator. Gate Valves can be Actuated for Considerably Less Cost than Ball Valves in Some Cases. The Height of the Valve and Actuator must be considered as Air Cylinders or Linear Electric Actuators must retract a Distance Equal to Stem Travel. The Height may be a Blessing in Disguise as the Actuator is Further Away from the Steam, Hot Oil or other Heat Source. Heat is a Large Contributor to Premature Actuator Failure in all Valve Types.
ANSI Flanged Ball Valve
ANSI Flanged Ball Valves When Flanged Ball Valves were introduced, the primary advantages over Gate Valve was that they were bubble tight shutoff and the ball/stem/handle rotation was 90 degrees, so height was not as much of an issue. Because they needed to be direct replacements for Flanged Gate Valves, the Flanged Ball Valves needed to be drop into place replacements. That required them to meet the ANSI Face-to-Face Dimension. This made it easier for Maintenance Workers to install them as no welding or rework was required. In order to meet the ANSI requirement, the valves were actually designed to be longer and were heavier than they needed to be to perform function. Ball Valves require Special Seats, Packings and Seals to Reach the Standard Temperatures the Gate Valves are Equipped for.
Actuated ANSI Flanged Ball Valve Flanged Ball Valves are becoming Easier to Actuate / Automate as many Valve and Actuator Manufacturers are Conforming to the New ISO5211 Standards. The Standard Primarily Defines the Bolt Hole Circle and the Square Shaft Dimension for Both Valves and Actuators. In the Past, many Valves and Actuators used a Variety of Bolt Hole Spacing and the Shaft Shapes and Dimensions also Varied. Splined, DD (Oblong), and many other Ball Valve Shaft Shapes Required Custom Brackets and Couplings to Mate the Various Valve and Actuators Dimensions. Many Valves and Actuators can Now be Direct Mounted, which can Reduce the Height of the Valve and Actuator by 2 or More Inches.
ANSI Wafer Ball Valve
Flanged Wafer Ball Valves Recently a new style of Ball Valve has been gaining favor in both Commercial and Industrial Application for new installations. That is the Wafer Ball Valve. The Wafer Ball Valve is typically Lower Cost, Lower Weight and takes up Less Space than an equivalent Split Body Flange Ball Valve.
Actuated Wafer Flanged Ball Valves Wafer Ball Valves can be Automated / Actuated with Electric Actuators and Air Actuators. They Normally Require a Bracket and Coupling to Mount the Actuator. Wafer Ball Valves are typically easier and less costly to actuate than Flanged Gate Valves. The Overall Height is also Less Than a Flanged Gate Valve.
The Bracket Height of the Gate Valve needs to be Taller than the Flanged Ball Valve and the Wafer Ball Valve as it the Electric Actuator Vertically Extracts the Stem from the Gate Valve.
Electric Gate Valve without Flanges
Electric Flanged Split Body Ball Valve
Electric Motorized Wafer Ball Valve
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