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Cushion sealing devices launched
Dynamic
Tougher shaft sleeves REFEL (reaction bonded) silicon carbide is widely used because of its resistance and frictional properties in mechanical seal faces and pump bearings. Due to increased life and reduced maintenance cost requirements of pump shaft sleeves, Tenmat is now offering these in REFEL. replacing the high chrome and hard coated sleeves used previously. Benefits include: long sleeve life (up to 30 times that of steel). more durable packing materials can be used without excessive wear of the shaft sleeve. low frictional properties reduce start-up torque and packing material wear rate. reduced shaft and packing wear rates mean extended gland adjustment intervals. Contact: Rupert Coggan, Tenmat Ltd, Bowdon House, Ashburton Road West, Trafford Park, Manchester, UK. Tel: +44 161 872 2181; Fax: +44 161 872 7596.
Material resists bio-degradable hydraulic fluids The cost of environmental pollution caused by hydraulic mineral oils is high. The spillage ofjust one litre of mineral hydraulic fluids is sufficient to contaminate one million litres of ground water. In Germany alone it is estimated that 35 thousand billion litres of water have been affected by mineral oil spillages. An ecological disaster threatens, not only because of water contamination, but also because of the severe degradation of soil affected by the loss of these fluids. For these reasons. lubricant manufacturers have concentrated on developing eco-friendly, rapidly bio-degrading hydraulic oils. These new fluids resolve environmental concerns, but raise the serious problem for manufacturers of hydraulic equipment, of incompatibility with existing oil sealing systems. Economos claims to be the first company to overcome this problem. Lubricant manufacturers have developed three different categories of bio-degradable hydraulic oils: l l
l
synthetic esters (HEES) natural esters (HETG) based on rape seed or plant oils polyalkylenglycols (HEPG)
Because of their physical properties and for economic reasons, synthetic esters are better suited for mobile
Sealing
Technology
No. 27
sealing
hydraulics applications, whereas natural esters are primarily used in farming and forestry equipment applications. Polyalkylenglycols are used only in special cases, due both to their high cost and to their immiscibility with water and the resulting incompatibility with mineral oils. At present, bio-degradable hydraulic fluids are more expensive than mineral oils, but do not incur the extra and significant cost of the disposal of contaminated soil. Another concern has been the incompatibility hitherto of the bio-degradable oils with conventional rubber or polyurethane sealing materials, resulting in seal failure after low usage. The hydraulic seal material developed by Economos is compatible with synthetic and ester based hydraulic fluids and remains efficient over a long working life. Materials that are incompatible with eco-friendly hydraulic fluids are the two classics, nitrile rubber (NBR) and hydrogenated nitrile rubber (H-NBR) of which only special types are suitable for use with mineral based hydraulic media. In the last decade, the polyurethane materials TPU and CPL have gained in importance in hydraulics sealing. None of these materials, however show sufficient chemical resistance to synthetic esters, the most important group of bio-degradable hydraulic media. Tensile strength deteriorates rapidly and the materials are eventually destroyed. After tensile testing, the standard polyurethane sealing material for 500 hours at 100°C. it was noted that they suffered a 50% reduction in strength after 500 hours and were annihilated after 1000 hours. Economos was prompted to develop polythene materials with higher degree of hydrolytic stability, making them suitable for use with natural and synthetic esters. The thermoplastic polyurethane sealing material H-Ecopur was first introduced, demonstrating resistance to all bio-degradable hydraulic fluids. In tests, in which the material was submersed in a synthetic ester at 100°C. there was no appreciable aging after 2000 hours. The subsequent development of G-Ecopur, improved further on the earlier material by demonstrating higher aging resistance and accordingly a much longer practical life. This material is now fitted to the company’s range of hydraulic seals as an effective barrier to the ester based bio-degradable fluids. Economos produces G-Ecopur as an injection moulded semi-finished material ready to be made in to seals on a specially developed CNC lathe. Hydraulic seals with diameters from 6 mm to 2 metres can be produced in this way. Contact: Economos (UK) Ltd, Seal Jet House, 83 Buckingham Road, Slough SLl 4PN, UK. Tel: t44 1753 696 565; Fax: +44 1753 696 181.
Cushion sealing devices launched Two new designs of pneumatic cushion seal, the V6 and the PP, have been introduced by Parker Seal Group’s packing division, which dampen cylinder pistons and take the place of mechanical check valves. The cushioning process begins when the cushion piston, called the “spud”, enters the dynamic sealing
5
General news
Garlock procures metallic gasket operation
Series PP profile cushion seal. lip. The seal moves to the back of the gland creating a seal on the inside diameter and the back of the cushion seal. Pressure increases between the piston and the cushion seal due to the movement of the piston towards the end of the cylinder. At the end of the stroke, pressure is equal on both sides of the cushion seal. By means of the return pressure - around 0.1 bar - the cushion seal moves axially until the stop cams reach the front of the groove. The pressure is allowed to bypass the outside diameter of the seal to allow constant acceleration. The spud on the other end of the piston enters the cushion seal at the other end of the cylinder, repeating the entire process. The V6 fits easily into housings with simple grooves, demonstrates consistent cushioning properties and is available in fluorocarbon, urethane and nitrile. The PP cushion can cope with misalignment of the cushioning spear to the cylinder head, because of its automatic centralising capability and the incorporation of two sealing systems into the design assures axial sealing. Contact: Packing Division, Parker Hannifin Corporation, PO Box 30505, Salt Lake City, UT 84130, USA. Tel: +l 801 972 3000; Fax: + 1 801 972 6703.
Seal Point
Furon’s metallic gasket business, has been acquired by Garlock Mechanical Packing, New York. Garlock principally makes soft gasket sealing products but the acquisition enables it to add Furon’s high temperature application gaskets - used mainly as replacement components in the chemical processing industry - to its product line. Furon feels Garlock is better equipped to fully develop the maintenance and repair market segment for high temperature gaskets. The Texas-based business will now operate as Garlock Metallic Gasket, within the company’s mechanical packing division. Contact: Garlock Inc., Mechanical Packing Division, 1666 Division Street, Palmyra, NY 14522-9350, USA. Tel: +1315 597 3284; Fax: +1315 597 3173.
Ceramaseal recommended for dual certification Ceramaseal, designer and manufacturer of advanced ceramic-to-metal sealed components, has been recommended for dual IS0 9001 certification in both Europe and the USA. Ceramaseal claims to be the first North American company in the ceramic-to-metal sealing industry to achieve this distinction. Ceramaseal manufactures components designed to withstand hostile environments and products include feed-through connectors. viewports, bushings and other components that use the company’s proprietary ceramic-to-metal sealing technology. They are used in a wide variety of applications including semiconductor equipment, superconductivity, linear accelerators and high energy physics. Through dual certification, Ceramaseal’s quality system will be registered by the Registration Accreditation Board for the US market and Radvoorakkrediterie for the European market. IS0 9001 is the quality system model for companies involved in the design/development, production, installation and servicing of products and services. Contact: Ren& Nicholas, CeramaseaI Corporation, Route 20, Post Office Box 260, New Lebanon, NY 12125, USA Tel: +l 518 794 7800; Fax: +l 518 794 8080.
Operation
6
of the PP cushion seal.
Sealing
Technology
No. 27
Tougher shaft sleeves REFEL (reaction bonded) silicon carbide is widely used because of its resistance and frictional properties in mechanical seal faces and pump bearings. Due to increased life and reduced maintenance cost requirements of pump shaft sleeves, Tenmat is now offering these in REFEL. replacing the high chrome and hard coated sleeves used previously. Benefits include: long sleeve life (up to 30 times that of steel). more durable packing materials can be used without excessive wear of the shaft sleeve. low frictional properties reduce start-up torque and packing material wear rate. reduced shaft and packing wear rates mean extended gland adjustment intervals. Contact: Rupert Coggan, Tenmat Ltd, Bowdon House, Ashburton Road West, Trafford Park, Manchester, UK. Tel: +44 161 872 2181; Fax: +44 161 872 7596.
Material resists bio-degradable hydraulic fluids The cost of environmental pollution caused by hydraulic mineral oils is high. The spillage ofjust one litre of mineral hydraulic fluids is sufficient to contaminate one million litres of ground water. In Germany alone it is estimated that 35 thousand billion litres of water have been affected by mineral oil spillages. An ecological disaster threatens, not only because of water contamination, but also because of the severe degradation of soil affected by the loss of these fluids. For these reasons. lubricant manufacturers have concentrated on developing eco-friendly, rapidly bio-degrading hydraulic oils. These new fluids resolve environmental concerns, but raise the serious problem for manufacturers of hydraulic equipment, of incompatibility with existing oil sealing systems. Economos claims to be the first company to overcome this problem. Lubricant manufacturers have developed three different categories of bio-degradable hydraulic oils: l l
l
synthetic esters (HEES) natural esters (HETG) based on rape seed or plant oils polyalkylenglycols (HEPG)
Because of their physical properties and for economic reasons, synthetic esters are better suited for mobile
Sealing
Technology
No. 27
sealing
hydraulics applications, whereas natural esters are primarily used in farming and forestry equipment applications. Polyalkylenglycols are used only in special cases, due both to their high cost and to their immiscibility with water and the resulting incompatibility with mineral oils. At present, bio-degradable hydraulic fluids are more expensive than mineral oils, but do not incur the extra and significant cost of the disposal of contaminated soil. Another concern has been the incompatibility hitherto of the bio-degradable oils with conventional rubber or polyurethane sealing materials, resulting in seal failure after low usage. The hydraulic seal material developed by Economos is compatible with synthetic and ester based hydraulic fluids and remains efficient over a long working life. Materials that are incompatible with eco-friendly hydraulic fluids are the two classics, nitrile rubber (NBR) and hydrogenated nitrile rubber (H-NBR) of which only special types are suitable for use with mineral based hydraulic media. In the last decade, the polyurethane materials TPU and CPL have gained in importance in hydraulics sealing. None of these materials, however show sufficient chemical resistance to synthetic esters, the most important group of bio-degradable hydraulic media. Tensile strength deteriorates rapidly and the materials are eventually destroyed. After tensile testing, the standard polyurethane sealing material for 500 hours at 100°C. it was noted that they suffered a 50% reduction in strength after 500 hours and were annihilated after 1000 hours. Economos was prompted to develop polythene materials with higher degree of hydrolytic stability, making them suitable for use with natural and synthetic esters. The thermoplastic polyurethane sealing material H-Ecopur was first introduced, demonstrating resistance to all bio-degradable hydraulic fluids. In tests, in which the material was submersed in a synthetic ester at 100°C. there was no appreciable aging after 2000 hours. The subsequent development of G-Ecopur, improved further on the earlier material by demonstrating higher aging resistance and accordingly a much longer practical life. This material is now fitted to the company’s range of hydraulic seals as an effective barrier to the ester based bio-degradable fluids. Economos produces G-Ecopur as an injection moulded semi-finished material ready to be made in to seals on a specially developed CNC lathe. Hydraulic seals with diameters from 6 mm to 2 metres can be produced in this way. Contact: Economos (UK) Ltd, Seal Jet House, 83 Buckingham Road, Slough SLl 4PN, UK. Tel: t44 1753 696 565; Fax: +44 1753 696 181.
Cushion sealing devices launched Two new designs of pneumatic cushion seal, the V6 and the PP, have been introduced by Parker Seal Group’s packing division, which dampen cylinder pistons and take the place of mechanical check valves. The cushioning process begins when the cushion piston, called the “spud”, enters the dynamic sealing
5
General news
Garlock procures metallic gasket operation
Series PP profile cushion seal. lip. The seal moves to the back of the gland creating a seal on the inside diameter and the back of the cushion seal. Pressure increases between the piston and the cushion seal due to the movement of the piston towards the end of the cylinder. At the end of the stroke, pressure is equal on both sides of the cushion seal. By means of the return pressure - around 0.1 bar - the cushion seal moves axially until the stop cams reach the front of the groove. The pressure is allowed to bypass the outside diameter of the seal to allow constant acceleration. The spud on the other end of the piston enters the cushion seal at the other end of the cylinder, repeating the entire process. The V6 fits easily into housings with simple grooves, demonstrates consistent cushioning properties and is available in fluorocarbon, urethane and nitrile. The PP cushion can cope with misalignment of the cushioning spear to the cylinder head, because of its automatic centralising capability and the incorporation of two sealing systems into the design assures axial sealing. Contact: Packing Division, Parker Hannifin Corporation, PO Box 30505, Salt Lake City, UT 84130, USA. Tel: +l 801 972 3000; Fax: + 1 801 972 6703.
Seal Point
Furon’s metallic gasket business, has been acquired by Garlock Mechanical Packing, New York. Garlock principally makes soft gasket sealing products but the acquisition enables it to add Furon’s high temperature application gaskets - used mainly as replacement components in the chemical processing industry - to its product line. Furon feels Garlock is better equipped to fully develop the maintenance and repair market segment for high temperature gaskets. The Texas-based business will now operate as Garlock Metallic Gasket, within the company’s mechanical packing division. Contact: Garlock Inc., Mechanical Packing Division, 1666 Division Street, Palmyra, NY 14522-9350, USA. Tel: +1315 597 3284; Fax: +1315 597 3173.
Ceramaseal recommended for dual certification Ceramaseal, designer and manufacturer of advanced ceramic-to-metal sealed components, has been recommended for dual IS0 9001 certification in both Europe and the USA. Ceramaseal claims to be the first North American company in the ceramic-to-metal sealing industry to achieve this distinction. Ceramaseal manufactures components designed to withstand hostile environments and products include feed-through connectors. viewports, bushings and other components that use the company’s proprietary ceramic-to-metal sealing technology. They are used in a wide variety of applications including semiconductor equipment, superconductivity, linear accelerators and high energy physics. Through dual certification, Ceramaseal’s quality system will be registered by the Registration Accreditation Board for the US market and Radvoorakkrediterie for the European market. IS0 9001 is the quality system model for companies involved in the design/development, production, installation and servicing of products and services. Contact: Ren& Nicholas, CeramaseaI Corporation, Route 20, Post Office Box 260, New Lebanon, NY 12125, USA Tel: +l 518 794 7800; Fax: +l 518 794 8080.
Operation
6
of the PP cushion seal.
Sealing
Technology
No. 27