Sliding Gate Valve Seats
Jordan's Sliding Gate Valve Seats...Simple Concept, Superior Performance
You'll notice something different in a Jordan valve... the unique sliding gate seat. A remarkably simple concept that offers sophisticated performance and benefits not found in traditional rising stem valves.
The sliding gate seat is made up of two primary parts: a moveable slotted disc and a stationary slotted plate. Together, these two parts achieve levels of performance, reliability and accuracy that are hard to find in other valve designs.
The disc is moved across the surface of the plate by the disc pin. When throttled open, the slots of the disc and plate align to allow the required flow through the seats. since the flow path is straight through the slots, turbulence, noise and wear are reduced. Another feature of this unique design is that the disc is supported from behind by the plate. This enables the seats to operate deficiency in the near closed position without being disturbed by the high, un-balanced forces a single seated globe valve would experience. This unique ability provides much higher rangeability than can be achieved wit a globe style valve while maintaining tight shutoff.
When the valve is closed, the disc and plate form a solid barrier to flow. The upstream pressure and a retaining guide combine to keep the disc and plate in constant contact, which eliminates the noisy chattering often encountered during valve operation. This construction also minimizes the hunting commonly found in conventional rising stem globe style valves.
Short Stroke, Fast Response
The stroke of the sliding gate valve is just 1/3 that of a globe style valve. This translates into fast response, reduced droop, longer diaphragm life and greater sensitivity. The disc requires very little travel to move from fully open to fully closed, and quickly corrects pressure or temperature deviations. The end result is faster response and more accurate control than provided with conventional seat designs.
The sliding gate valve is inherently quieter than other types of valves because:
- The disc and plate remain in constant contact, eliminating chatter
- The straight-through flow passage minimizes turbulence, a prime cause of valve noise
- The multiple orifices in the plate and disc divide the flow into smaller flow components
Quiet operation is a standard feature of Jordan sliding gate valves. You won't find a premium price adder for "low noise trim".
The seats are self-cleaning, with any leak-producing deposits being cleaned off by the sharp shearing action of the disc moving across the plate. The combination of the overlap, self-cleaning feature, upstream pressure, and flatness of the plate assures shutoff that actually exceeds the sliding gate valve's ANSI Class IV rating.
Jordan's sliding gate seats are pre-lapped at the factory and are self-lapping in operation. This maintains their tight shutoff characteristics over the long service life of the valve. You'll find that shutoff often improves over time as Jordan sliding gate valves actually "wear in, instead of wear out".
Jorcote Seat Materials
Jorcote, our standard seat material, is a proprietary ceramic based composite coating on Stainless Steel, This material is extremely hard (@RC85), has an extremely low co-efficient of friction, and delivers outstanding performance. It is suitable for all temperatures from cryogenic to +450°F. Factory testing at 250 psi steam shows that after over 70,000 full stroke cycles, Jorcote will still shutoff well below ANSI Class IV leak limits.
Easy to Maintain
The simple design of the sliding gate valve eliminates most maintenance problems, and those that may be required are easy to perform. Disassembly of the valve is very simple and, since the seats are not welded to the stem, they conveniently lift out of the body. Should your flow requirements change, interchangeable Cv's are available in flow coefficients as low as 0.0008 and as high as 600 (depending on body size).
In addition, on control valves, the action an be changed from reverse (air-to-open) to direct (air-to-close) by simply rotating the disc and plate 180°. No change is required inside the actuator. Furthermore, since the disc and plate operates in a continually lapping condition, you never need to pull the valves our of the line to lap the trim in order to ensure tight shutoff performance.
Size and Weight
As the line size increases, so too does the size and weight of the valve. Because of Jordan's short stroke length, a sliding gate valve is typically shorter and lighter weight than a globe-style valve. As an example, Jordan's 2" sliding gate control valve is less than 13" tall and weighs less than 35 pounds.