Product category:
Process and OEM Valves
News Release from: Tyco Flow Controls | Subject: Dewrance parallel slide gate valves
Edited by the Engineeringtalk Editorial
Team on 28 May 2004
Cost-effective alternative to wedge gate
valves
Dewrance parallel slide gate valves offer excellent reliability and outstanding performance in high-pressure applications in the power industry.
Dewrance parallel slide gate valves offer excellent reliability and outstanding performance in high-pressure applications in the power industry Dewrance parallel slide gate valves boast a "follower-eye" Venturi design, which allows for a smooth flow path between the seats, and protects seat faces from system debris
This article was originally published on Engineeringtalk on 5 Jun 2003 at 8.00am (UK)
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The design also enables use of a physically smaller and lighter valve than wedge gate alternatives, to meet a pressure drop equivalent of L/D = 13.
The parallel slide configuration uses system pressure and disk position to provide positive isolation.
When the valve is opened or closed, the positioning of two flat spring loaded disks will either seal or open the pipeline passage.
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Closure is achieved by positioning the discs between the seat faces in the valve body.
No additional torque is required to achieve a positive seal once the discs are in position - the pressure differential across the disk forces the outlet disc against the seat, creating a tight seal which is far superior to wedge gate valve alternatives.
In comparison with full bore wedge gate valves, the Dewrance parallel slide gate valve solution offers a lower pressure drop, minimised flow turbulence, and a reduction of 30% in actuator size and cost.
Parallel Slide configurations also permit higher allowable seat velocity, a low operating torque, and improved sealing which is assisted by the line pressure.
The nonwiping action of wedge gate valves can trap debris between the wedge and the valve seat, which can cause leakage, erosion and prevent sealing.
In the parallel slide valve, the discs "wipe" over the seats during closing, removing any debris which could interfere with valve operation.
Parallel slide valves are suitable for a variety of applications including main steam isolation, boiler feed pump isolation, high pressure feed heater isolation and bypass, blow down service, blow off service, gland steam system drains, steam turbine inlet isolation, economiser recirculation and spray water duties.
Dewrance parallel slide valves are available with a range of accessories, including bypass, equalising bypass, equalising pipe and drain valves.
The valves can also be supplied with a "vee-ported" seat and special pattern discs for flow regulation duties.
The valves can also be equipped with bevel gear, bevel and spur gear and motorised operators.
Available in sizes from 5 to 24in and pressure classes 1000, 1690, 1715, 2260, 2500 and 2850, Dewrance parallel slide gate valves are constructed to ASME B16.34-1996 and constructed in cast carbon steel, alloy steel and modified 9% chrome (C12A).
Dewrance parallel slide gate valves are available through Tyco Valves and Controls.
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