Categories
- Machine Tools: Cutting (3,941)
- Machine Tools: Metalforming, shearing, folding and punching (1,496)
- Machine Tools: moulding (1,066)
- Cutting tools (1,786)
- Welding and Joining (1,496)
- Finishing, preparation, coating and painting (1,033)
- Automation and assembly systems (1,084)
- Manufacturing support (8,619)
- Industry news, commerce, exhibitions, education (8,223)
- Packaging (2,867)
- Specialist Manufacturing Sectors and Metals Producing (1,326)
- Books, CDs and Videos (195)
- IT for manufacturing management and production (3,233)
- IT for engineering, industrial and commercial applications (4,850)
- Manufacturing IT hardware and communications (1,570)
- Used machinery and machine tools (30)
- Materials handling and storage (930)
- Wood and non-metallics working (73)
- Metrology instruments and systems (3,810)
- Testing and quality control systems and services (4,957)
- Subcontracting services (1,154)
Low-friction sealing rings reduce valve torque
A
James Walker and Co product story
Edited by the Manufacturingtalk editorial team
Nov 14, 2003
Low-friction sealing rings are designed to reduce significantly the torque needed for efficient valve operation - effectively cutting power consumption and allowing use of smaller actuators.
James Walker's new Supagraf LF low-friction sealing rings are designed to reduce significantly the torque needed for efficient valve operation - effectively cutting power consumption and allowing smaller actuators to be used.
They also have the potential to cut shaft seal friction on pumps that use graphite rings.
The new rings are particularly effective on valves that handle dry gases and other process media where the friction on standard graphite seals is unacceptably high, leading to valve stem sticking and hesitation.
Independent tests confirm the low-friction claims.
When fitted in a gland housing at 10MPa and 40MPa compressive stress, Supagraf LF displayed friction coefficients of 0.11 and 0.07, respectively.
The coefficients for standard graphite rings were exactly double at 0.22 and 0.14.
Torque-versus-cycle results proved even more impressive.
In extended tests, valve stem torque remained constant at 5Nm for Supagraf LF, whereas for standard graphite rings the torque rose from 21Nm to 25Nm during the first 300 operating cycles.
With a lubricated valve stem, the torque for standard graphite rings increased from 7Nm to 23Nm during the first 150 cycles as the lubricant was removed by valve action.
The secret of success for Supagraf LF is a special coating, 5æm thick, sinter-bonded to the surfaces of the expanded graphite rings before the moulding process.
With this coating the rings have performed 20,000 low friction valve stem cycles with fugitive emission control of methane gas to 50ppm or less.
Further tests showed satisfactory performance up to 60,000 cycles with normal manual adjustments along the way.
The new rings will operate at temperatures from -200degC to +350degC, or at a maximum system pressure in valves of 150bar.
They are chemically inert to media in the range pH 0-14, and also have a fire-safe capability.
Supagraf LF moulded rings are supplied in endless form or, for ease of installation, with a single split and as matched scarf-split halves.
Inside diameters range from 2mm to over 1100mm: sections from 1.5mm to 40mm.
Not what you're looking for? Search the site.
Contact James Walker and Co
Tel +44 1270 536000
Request information
Other James Walker and Co stories
-
Industrial chimney sealing service expanded
An industrial chimney sealing service has been expandd and includes full custom-design and installation service plus the use of top-grade fluoroelastomer and fluoroplastics materials. -
Boiler door gasket resists high heat/pressure
A boiler door braided graphite ribbon gasket that resists high temperature and pressure has excellent resistance to oxidation and chemical attack. -
Gland packing reduces stockholding costs
A superior quality gland packing from James Walker, Supagraf RibbonPak SC, is set to reduce stockholding and operating costs at power stations, processing plants and many other industrial sites. -
Tension control fasteners for car couplings
Alstom, world leading supplier of rail products, services and systems, is to use tension control fasteners, from James Walker RotaBolt, on the intermediate car couplings of its new Modular trains. -
High-speed abrasive 'water-jet' cutting service
James Walker has introduced a new enhanced high-speed abrasive 'water-jet' cutting service following the installation of a Calypso Water Jet Cutting System at its Cockermouth Custom Gasket plant.
