Valves are imperative for isolation and control functions, and can be found in a broad range of industries such as Oil & Gas, Water & Wastewater, Food & Beverage and Hydraulics & Pneumatics. We supply seal products into valve applications in a variety of styles including ball, gate, flap, plug, butterfly, spool, check and solenoid valves.
Characteristics of valve sealing
There are many challenges involved in valve application sealing. Conditions and application parameters can vary with temperature extremes from cryogenic up to 325°C, and pressures up to 1000+ bar. We need to carefully consider the materials to suit all fluid compatibility required. Often the seal design requires low breakout friction and offers no stick-slip following prolonged static periods when the valve is not used. Alongside this, customers require long service life and minimal maintenance.
Valve styles include ball, gate, flap, butterfly, spool, check and solenoid valves. Also different types of actuation include manual, pneumatic, hydraulic and electro-mechanical.
Different areas of the valve demonstrate different sealing requirements.
Valve sealing areas
Actuation
There are a range of sealing solutions to suit the variety of actuation types employed with valves. This includes diaphragms for pneumatic actuation, rotary and linear hydraulic and pneumatic seals, and gaskets and O-rings. Seal materials are available to suit all ranges of temperatures and media associated with the actuator and any external contaminants it encounters.
Body bonnet joint
This is a static sealing location that can often be sealed with an O-ring (a wide range of materials are available to satisfy fluid compatibility). However dependent on the fluid, pressures and temperatures, metal seals can be more suited to the application. Additionally, housing deflection under pulsating system pressures may worsen compression set sealing issues. Therefore, a custom gasket design could be potentially more suitable than an O-ring. For subsea valves, a sealing solution capable of handling alternating pressure regimes and multiple media types may be required.
Stem
A critical and dynamic sealing location with often demanding requirements. Depending on the application of the valve, the seals used here may see frequent dynamic operation and will require a long wear life. In other cases, the valve may be static for long periods and then require operation with minimal break-out friction forces. In all cases, reliable sealing is paramount.
Seat body
Valve seats are often mounted in a housing or carrier which has a sealed interface within the valve body and in these cases it can be a critical location to seal correctly. Dependent on the design, the seal location may be subject to upstream or downstream pressures at various points. In some cases fluid flow through the valve can pull or wash-out seals from their grooves if they are not designed to prevent this. As pressure conditions change with valve operation, the seals here may be required to withstand small (but sometimes frequent) movements of the carrier without sticking or wearing.
Valve Seat
A wide variety of elastomers and engineered polymer materials can be moulded or machined to suit valve seat components. Bonded rubber to metal or rubber to plastic seals can provide bespoke solutions. These offer benefits in terms of space envelope, component count or ease of assembly.
Design & Development for valve sealing applications
Our engineering team understand the application demands associated with valve sealing and can support our customers with the design of seals for every position within the valves.
We provide a complete design service; from initial seal geometry and profile choice, to material selection and prototyping, through to final production. This is utilised with our seal design experience and materials expertise, alongside technology such as 2D/3D CAD and FEA analysis. These simulate performance before finalising each individual seal design.
We are familiar with the requirements of individual markets and their valve applications. Our seals are manufactured in materials with approval requirements such as NORSOK M-710, ISO23936-2, NACE, WRAS and FDA.
For more on our design and engineering service, see our dedicated page HERE