Sherwood compressed gas valves are sturdy pieces of kit — and they have to be. The high pressures contained within a compressed gas system put components under immense strain, so facility managers across all industries need to be able to rely on their equipment.
The team at Sherwood is well aware of just how important these valves are to the end user. They also consider the strict regulatory requirements and operating standards that govern any industry working with compressed gases. So the products they manufacture are designed to go above and beyond these industry minimums.
To achieve this, Sherwood produces and deploys internal components that have been precision machined to suit the unique requirements of a compressed gas system — meeting even the strictest of OSHA national standards as well as international standards. This is backed up with automated processes within the assembly and testing schedule. Automation ensures repeatable and reliable results during testing and production, eliminating human error that can cause significant problems in manufacturing and reducing the costs associated with the process.
At Chemtech, we provide a wide range of Sherwood valves, including specialty Sherwood chlorine and oxygen valves. Browse our product range to discover more about this, or reach out to our team if you have any questions.
Today, though, we’re taking a closer look at what goes on inside a Sherwood compressed gas valve, helping you understand how these components work.
Opening or Operating Mechanism
At the top of the valve is the opening or operating mechanism. Typically, this will be a hand wheel that can be turned to manipulate the threads within the valve stem, reducing or increasing the gas flow as required. This mechanism must be straightforward to operate, achieving complete manual control without delay whenever needed. The Sherwood valve achieves this thanks to a sturdy hand wheel, designed to be comfortable to operate for human users. Meanwhile, the valve’s inner workings reduce the torque required to open and close the valve, even at higher pressures.
Upper and Lower Stem
The upper and lower stems come together to open and close the valve, either permitting or prohibiting the flow of gas depending on the configuration of the stems. Within a Sherwood compressed gas valve, these stems employ a direct drive mechanism — the upper stem is driven directly by the hand wheel or operating mechanism at the top of the valve, achieving swift responsiveness and easy operation.
Rubber O-rings sit between the upper and lower stems, creating a seal that eliminates leaks and escaping gases. The GSV model features a single optimized O-ring, while the GSH-V features double O-ring seals. These components make for easy and effective operation, enabling opening and closing with only small applications of torque to the opening mechanism.
Bonnet and Metal-to-Metal Seal
The bonnet sits on top of the valve’s body, screwing directly into this body to provide a strong and sturdy connection between the upper stems, operating mechanism, threads, and components within the lower section of the valve. While the connection is strong enough to withstand high pressures, this concentration can cause other problems — pressure in the threads can cause these threads to stick, making operation difficult. This is why Sherwood compressed gas valves are engineered with an improved metal-to-metal seal, preventing pressure build-up in the valves’ upper threads.
This is the bulk of what you can see when you look at the valve from the outside — the housing that keeps all constituent parts protected and supported. But there’s also a lot going on beneath the hood. This body is made from heavy-duty forged brass, giving the valve the durability it needs to sustain the high pressures of compressed gas. The body and other components within the valve are tested to be 100% leakproof with low-mass helium gases. When combined with leak detection measures, Sherwood Valves offer exceptional safety around the facility.
Compressed gases vary in terms of precise pressure. Typically, any gas or gas mixture of at least 40 psi at 70 degrees Fahrenheit or exceeding 104 psi at 130 degrees Fahrenheit will be classed as a compressed gas. Liquids with a vapor pressure of at least 40 psi at 100 degrees Fahrenheit may also be placed in this category. Facility managers must ensure they are working with valves that are adequately rated for the purpose, particularly if they are handling gases at a higher pressure level. The durable valve body, and the precision-engineered components of the valve, help to offer reliable operation and safety, providing the ratings are adhered to.
Inlets and Outlets
Inlet and outlet points enable the regular and reliable flow of gas when the valve is opened. These are designed to support a broad range of customer needs and offer compliance with the different regulatory codes around the world. Inlets can be tapped according to customer requirements, integrating with dip tubes within the system.
Pressure Release Mechanism
The Pressure Relief Device, or PRD, forms the pressure release mechanism on the Sherwood compressed gas valve. This component features a unitized plug design built for reliable operation and exceptional levels of safety. The PRD offers excellent flow characteristics while preventing tampering and unauthorized alteration to the valve. If the valve is incorrectly assembled, it will not function, so the design essentially guarantees proper assembly and provides valuable peace of mind for you and your team
Discover More About Sherwood Gas Valves
This article is part of a short series we are doing here at Chemtech, bringing you closer to the Sherwood gas valves that so many of our customers rely on. Check back on our news and articles page in the future as we break down the features and inner workings of some of Sherwood’s specialist gas valves.