- Email: [email protected]
Additional new piston ring material introduced
NEWS
New valve stem seal to improve quality of emissions SKF has developed and patented a new valve stem seal for the engines of heavy-duty vehicles, such as trucks and buses, to improve the quality of emissions and provide improved engine operation. The seal, which has been developed at the company’s facility in Leverkusen, Germany is designed to withstand the pressure in the exhaust and intake ports of a turbocharged truck or bus engine and maintain its primary function as an oil-metering device. The new seal is expected to reach production in early 2006, and is currently being evaluated by a major European truck manufacturer. Valve stem seals are engineered to allow a small amount of oil to pass through the lip, known as oil-metering, to lubricate the valve stem and valve guide interface of an engine. If too much oil passes through the lip of the seal, emissions are increased and coke builds up on the valve, potentially causing the engine to lose power or even fail. If too little oil passes through the lip of the seal, the valve does not receive enough lubrication and will scuff, which can lead to seizure. High pressure can exist in the exhaust and intake ports of engines for heavy-duty vehicles. This can cause gases to escape through the valve stem seals into the cylinder head. As the gases blow by, the valve
stem seal may not be able to perform its primary function as an oil-metering device, so lubrication problems can occur. In addition, when the high pressure from an exhaust brake is present and the valve stem seal lip opens, the high volumes of air then flowing past the seal can overload the capacity of the breather system, which also has to separate oil from the air. The breather system feeds this air back into the intake manifold so any oil present is burned, causing poor emissions quality and deposits on the valves. This also forces the engine manufacturer to oversize the system, so that these worst-case conditions can be accommodated without adversely affecting emissions. Thus, lower capacity in the breather oil separation system means cost savings for the engine manufacturer. The new seal design allows the primary sealing lip to function independently of the pressure applied, by protecting it with an independent secondary lip. This lip resists high pressures in the exhaust and intake ports of the engine without opening, thus maintaining the primary function of the seal as an oil-metering device. Contact: SKF Business & Technology Park, Postbus 2350, NL-3430 DT Nieuwegein, The Netherlands. Tel: +31 30 60 75 608, Email: [email protected], Web: www.skf.com
Water pump seal compensates for vibrations The Simrax CS850 is a new mechanical face seal for water pumps driven directly by tooth wheels or chains in cars and trucks. Elastomer components provide the isolation.
The CS850 is a new mechanical face seal for automotive water pump applications from Freudenberg Simrax that has been designed to reduce the effects of vibration on seal performance. The innovative sliding ring bearing makes directly driven water pumps more robust. Water pump seals are often driven by toothed belts or a chain drive and can be subject to axial, radial and tangential vibrations. This new seal has elastomer components which largely isolate the seal rings from vibration, and a wearresistant face material combination of silicon carbide/silicon carbide. Each seal ring is surrounded by an elastomer component specifically designed to damp out all the vibration components. The axial vibration components are also minimized by modifying the spring contact pressure. The spring contact pressure and spring force transmission to nearby sealing components have been optimized in conjunction
with a leading spring supplier, with the results being verified on test rigs by endurance testing. To improve the torque synchronization, an elastomer-supported hexagon carrier has been developed, with optimized contact surfaces helping to ensure reliable torque transmission even under critical vibration loads, and to reduce radial vibration components to a minimum. Since the high level of vibrations makes it unusually difficult to transfer torque to the mechanical face seal, the seal is provided with additional wear resistance by a CVD coating. The open construction of the seal facilitates heat dissipation to meet the high demands placed on water pumps in trucks. Contact: Freudenberg Dichtungs- und Schwingungstechnik KG, Hohner Weg 2–4, D-69465 Weinheim, Germany. Tel: +49 6201 800, Fax: +49 6201 88 3060, Web: www.freudenberg-ds.com
Additional new piston ring material introduced
The new valve stem seal for truck diesel engines from SKF is designed to maintain reliable operation during the substantial pressure changes that can occur in the engine inlet and exhaust system.
Sealing Technology October 2005
France Compressor Products has announced a further a new specialty performance material for reciprocating compressor piston rings, rider bands and packing rings for ‘bone-dry’ applications. This material, which is a further addition to those announced recently [Sealing Technology, July], is called FSP 2020. It has been specifically designed for high-pressure, non-lubricated air compressors. A particular target for the material is compressors in the PET bottle blowing industry.
Contact: France Compressor Products, 4410 Greenbriar Drive, Stafford, TX 77477, USA. Tel: +1 281 207 4600, Fax: +1 281 207 4612, Web: www.francecompressor.com
Editor’s comment: This area of piston rings and bearings to work in gas that is ‘bone dry’ to a very few ppm, and what also may be inert gas, is an interesting area as the transfer film properties of the plastic are crucial to success. For commercial reasons the manufacturers are extremely coy about the material compounds used. 3
New valve stem seal to improve quality of emissions SKF has developed and patented a new valve stem seal for the engines of heavy-duty vehicles, such as trucks and buses, to improve the quality of emissions and provide improved engine operation. The seal, which has been developed at the company’s facility in Leverkusen, Germany is designed to withstand the pressure in the exhaust and intake ports of a turbocharged truck or bus engine and maintain its primary function as an oil-metering device. The new seal is expected to reach production in early 2006, and is currently being evaluated by a major European truck manufacturer. Valve stem seals are engineered to allow a small amount of oil to pass through the lip, known as oil-metering, to lubricate the valve stem and valve guide interface of an engine. If too much oil passes through the lip of the seal, emissions are increased and coke builds up on the valve, potentially causing the engine to lose power or even fail. If too little oil passes through the lip of the seal, the valve does not receive enough lubrication and will scuff, which can lead to seizure. High pressure can exist in the exhaust and intake ports of engines for heavy-duty vehicles. This can cause gases to escape through the valve stem seals into the cylinder head. As the gases blow by, the valve
stem seal may not be able to perform its primary function as an oil-metering device, so lubrication problems can occur. In addition, when the high pressure from an exhaust brake is present and the valve stem seal lip opens, the high volumes of air then flowing past the seal can overload the capacity of the breather system, which also has to separate oil from the air. The breather system feeds this air back into the intake manifold so any oil present is burned, causing poor emissions quality and deposits on the valves. This also forces the engine manufacturer to oversize the system, so that these worst-case conditions can be accommodated without adversely affecting emissions. Thus, lower capacity in the breather oil separation system means cost savings for the engine manufacturer. The new seal design allows the primary sealing lip to function independently of the pressure applied, by protecting it with an independent secondary lip. This lip resists high pressures in the exhaust and intake ports of the engine without opening, thus maintaining the primary function of the seal as an oil-metering device. Contact: SKF Business & Technology Park, Postbus 2350, NL-3430 DT Nieuwegein, The Netherlands. Tel: +31 30 60 75 608, Email: [email protected], Web: www.skf.com
Water pump seal compensates for vibrations The Simrax CS850 is a new mechanical face seal for water pumps driven directly by tooth wheels or chains in cars and trucks. Elastomer components provide the isolation.
The CS850 is a new mechanical face seal for automotive water pump applications from Freudenberg Simrax that has been designed to reduce the effects of vibration on seal performance. The innovative sliding ring bearing makes directly driven water pumps more robust. Water pump seals are often driven by toothed belts or a chain drive and can be subject to axial, radial and tangential vibrations. This new seal has elastomer components which largely isolate the seal rings from vibration, and a wearresistant face material combination of silicon carbide/silicon carbide. Each seal ring is surrounded by an elastomer component specifically designed to damp out all the vibration components. The axial vibration components are also minimized by modifying the spring contact pressure. The spring contact pressure and spring force transmission to nearby sealing components have been optimized in conjunction
with a leading spring supplier, with the results being verified on test rigs by endurance testing. To improve the torque synchronization, an elastomer-supported hexagon carrier has been developed, with optimized contact surfaces helping to ensure reliable torque transmission even under critical vibration loads, and to reduce radial vibration components to a minimum. Since the high level of vibrations makes it unusually difficult to transfer torque to the mechanical face seal, the seal is provided with additional wear resistance by a CVD coating. The open construction of the seal facilitates heat dissipation to meet the high demands placed on water pumps in trucks. Contact: Freudenberg Dichtungs- und Schwingungstechnik KG, Hohner Weg 2–4, D-69465 Weinheim, Germany. Tel: +49 6201 800, Fax: +49 6201 88 3060, Web: www.freudenberg-ds.com
Additional new piston ring material introduced
The new valve stem seal for truck diesel engines from SKF is designed to maintain reliable operation during the substantial pressure changes that can occur in the engine inlet and exhaust system.
Sealing Technology October 2005
France Compressor Products has announced a further a new specialty performance material for reciprocating compressor piston rings, rider bands and packing rings for ‘bone-dry’ applications. This material, which is a further addition to those announced recently [Sealing Technology, July], is called FSP 2020. It has been specifically designed for high-pressure, non-lubricated air compressors. A particular target for the material is compressors in the PET bottle blowing industry.
Contact: France Compressor Products, 4410 Greenbriar Drive, Stafford, TX 77477, USA. Tel: +1 281 207 4600, Fax: +1 281 207 4612, Web: www.francecompressor.com
Editor’s comment: This area of piston rings and bearings to work in gas that is ‘bone dry’ to a very few ppm, and what also may be inert gas, is an interesting area as the transfer film properties of the plastic are crucial to success. For commercial reasons the manufacturers are extremely coy about the material compounds used. 3