- Email: [email protected]
Longer-lasting grease
_Pl J iflims Increasing bearing life Subsurface initiated spalling is the failure mode which is the generally accepted basis for calculating the service life of ball and roller bearings. Often, however, the dominant and swifter mode of failure is surface initiated spalling in which, for example, fatigue cracks propagate from debris dents. Filter performance is therefore important but, surprisingly, there has been a lack of data on how it affects bearing life. Research at NASA's Lewis Research Center helps make good this lack and shows how fine filtration can increase bearing life. Fatigue tests were conducted on groups of ball bearings in a recirculating lubrication system having one of four levels of filtration. The four test filters used had absolute particle removal ratings of 3, 30, 49 and 105/am. Four series of tests were conducted in which contaminants, similar to those found in gas turbine engines, were injected into the filter supply line at a constant rate. To provide baseline data, a fifth series used a non-contaminated lubricant. Bearing life and running track condition generally improved with fine filtration. Bearings tested using contaminated oil with 3/am and 30/am filters had statistically equivalent lives, approaching those in the uncontaminated oil. Bearing lives with a contaminated lubricant and 49 tam filter were approximately half those of bearings in the baseline noncontaminated oil tests. The weight loss of unfailed bearings tested with the four filters were, respectively 1.9, 3.2, 4.2 and 89 times the weight loss of the baseline bearings. Surface distress on tracks and wear of bearings increased progressively with coarser filter size. The probable failure mode appeared to shift from predominantly subsurface initiated fatigue for bearings in the baseline tests using noncontaminated oil and a 49 tam filter. In an account of background developments, the report notes that designers have been reluctant to specify fine filtration levels (less than 10/am absolute) even though they have known that aircraft turbomachinery is prone to lubricant contamination and that this causes problems. It has been thought that fine filtration would
102
not improve component reliability sufficiently to justify the possible increase in system cost, weight and complexity. It has also been presumed that free filters would clog more quickly, have a higher clean pressure drop and generally require more maintenance than currently used filters. It has been shown that these assumptions are not always correct and, recently, a 3/am filtration was selected for turbine engines powering advanced US helicopters. It has also been shown desirable to pre-filter lubricating oil through an extra time filter in filling systems in critical applications such as those in aircraft. Further information is contained in a 32-page report 'Effect of filtration on rolling-element-bearing life in a contaminated lubricant environment' by S.H. Loewenthal et al, reference T78 6747, available as microfiche £1.19 or reproduced paper-copy £2.80, from TechAlert, TRC, Orpington, Kent, BR5 3RF, UK*
Protecting hot surfaces Blades and other components in gas turbines are subjected to extremely harsh thermal conditions and require some surface protection system if premature failure is to be avoided. With efforts to improve turbine efficiency by increasing operating temperature, this poses increasingly difficult materials engineering problems. The problems and principles of high-temperature surface protection systems and recent developments are reviewed in a NASA report. The report gives details of the various coatings and deposition ntethods which are now available. Attention is concentrated on the gas turbine application, but many of the basic principles are applicable wherever metals are subjected to very hot gas flOWS.
In gas turbines, the primary concern is to protect alloys of nickel and cobalt from degradation by four interactive processes: oxidation, erosion caused by particulates, hot corrosion by impurities derived from the fuel or air, and thermal fatigue resulting from cyclic thermal stresses. The surface protection system has to resist or *Synopses provided by TechA lert. Remittances payable to Department o f Industry
TRIBOLOGY international April 1979
retard these processes while not causing any alloy reactions which would degrade their strength or ductility. The basis for high-temperature surface protection systems in gas turbines are alloys of the type MCrA1X: M can be one or more of Ni, Co or Fe; X denotes oxide scale adherence additives such as noble or reactive metals, such as Pt, Zr, Y or Si, or finely dispersed oxides, such as T h O 2 , Y203 or Z r O 2. The review outlines the protection mechanisms and discusses the selection and formation of the coating systems and their oxidation, hot corrosion and thermal fatigue performances. Three different types of system are discussed: aluminide coatings where the coating is formed by a diffusion reaction with the substrate; overlays where neither the formation nor the composition of the coating depends on a substrate diffusion reaction; and thermal barriers where an insulating coating, usually of stabilized ZrO2 is superimposed on a bond overlay coating. Coating deposition methods discussed include: the pack cementation process for aluminide coatings; physical vapour deposition; sputtering and plasma spraying for overlay coatings; and plasma spraying for thermal barriers. Current developments aimed at improving the effectiveness of the various coatings are reviewed. Further information is contained in a 17-page report: 'High temperature surface protection' by S.R. Levine, reference N78-17340, available as microfiche £1.19 or reproduced paper-copy £1.50, from TechAlert, TRC, Orpington, Kent, BR5 3RF, UK*
Longer-lasting grease A new grease lubricant, offering improved machine reliability and savings in maintenance costs, has been specified for use in US naval vessels. A 1974 report, recently released by the US Naval Ship Research and Development Center, describes simulated severe long-service life tests giving an indicated bearing life with the new grease of almost three times that with conventional greases. The grease was tested in deep-groove (Conrad-type) 75 mm bore, singleshield, precision (noise-tested) ball
beatings supporting a horizontal shaft. Tests were conducted at a shaft speed of 3600 rev/min (270 000 DN) with the bearings under an axial load of 4000N. Bearing outer ring temperature was set at about 93°C, slightly higher than would be expected in service. All the test bearings were stopped after 11 070 h successful running with the new grease. Four were then left running. One failed after 19 940 h and another failed after 20 450 h; the other two were sitll running successfully after 26 800 h. Test data lead to a conservative estimate of at least 11 000 hours as the life 90 percent of the bearings would be expected to exceed without lubrication failure using the new grease. In comparison equivalent bearing lives using two conventional greases were 4000 hours (90 per cent confidence limits of 3444 and 5297 hours) with one grease and 4230 hours (90 per cent confidence limits of 2963 and 6326 hours) with other. Tests of the greases on vertical shafts were underway when the report was being prepared. Further information is contained in a 28-page report 'Long-life grease performance in horizontal shaft rolling contact bearings for shipboard machinery' by L.G. Schneider and P. Lassovszky, reference AD-923 094, available as microfiche £1.19 or reproduced paper-copy £2.80, from TechAlert, Technology Reports Centre, Orpington, Kent, BR5 3RF, UK*
Solid lubricant synergisms Surprisingly little has been done to investigate the mechanisms responsible for the synergistic improvement of solid film lubricants by non-lubricant additives such as antimony trioxide (Sb203). Without such work, significant advances in solid film lubrication technology seem unlikely. A substantial contribution to filling this gap is now provided by a US Air Force study carried out to identify the mechanisms (chemical, mechanical and tribochemical) by which Sb2 O3 additives enhance molybdenum disulphide (MoS2) lubrication. Among the more important ffmdings are that the Sb203 additives: inhibit the oxidation of MoS2, especially in the range 300°C to 600°C; reduce the pressures required to form pellets; alter the morphology and chemistry of burnished pellet surfaces.
The report also indicates questions which will require further work and describes the design and construction of a friction tester for solid lubricant evaluation. Further information is contained in a 53-page report 'Synergistic mechanisms of solid lubricants' by R.S. Harmer and C.S. Passtano, reference AD-A054 741, available as microfiche £1.19 or reproduced paper-copy £4.10, from TechAlert, Technology Reports Centre, Orpington, Kent, BR5 3RF, UK*
Polymer wear Better understanding of polymer wear is provided by a report on a US Army contract. Wear tests were carried out by sliding a normally loaded polymer specimen (PVC, polychlorotrifluoroethylene or nylon) on a roughened mild steel surface. The weitr mechanism is determined by whether the surface asperities fully penetrate the polymer (real and apparent areas of contact equal) or whether the penetration is only partial (real area less than apparent area). With full penetration the polymer shears off at an angle to the surface which correlates directly with the polymer's energy to rupture and inversely with its wear rate. With partial penetration the wear data are directly related to the depth of penetration. This is a function of the polymer yield strength and the bearing area curve of the surface. Surface profile statistics are vital in wear prediction but it is important to ensure that the only parts of the surface considered are those that are actually in contact with the polymer.
Both the friction force in metal ploughing and groove height (corresponding to groove volume) decrease linearly with increasing ultimate shear strength. Metal grooving is primarily by plastic deformation with only occasional metal removal. The relation between the groove width D and applied load W is given by W = kD n ,
where n is a constant depending on the material, which satisfies Meyer's law. Further information is contained in a 25-page report 'Friction and wear of'metals with a single-crystal abrasive grit of silicon carbide - Effect of shear strength of metal' by K. Miyoshi and D.H. Buckley, reference T78 6312, available as microfiche £1.19 or reproduced paper-copy £1.50, from TechAlert, Technology Reports Centre, Orpington, Kent BR5 3RF, UK*
Fretting There is some confusion in the liter, ature over the influence of slip amplitude on fretting wear. It has been suggested that this is due to the difficulties in measuring slip amplitude accurately.
Further information is contained in a 6-page report 'Depth of penetration as a predictor of the wear polymers on hard, rough surfaces' by J.H. Warren and N.S. Eiss, Jnr, reference T79 843, available as microfiche £1.19 or reproduced paper-copy £1.50, from TechAlert, Technology Reports Centre, Orpington, Kent, BR5 3RF, UK*
Metal abrasion and shear strength A N A S A report provides new data on
the plastic deformation and removal of metals, and on the friction force in sliding in terms of shear strength. Sliding friction experiments were conducted with spherical silicon carbide runners on thirteen different metals, and with riders of the same metals sliding on silicon carbide. The
two sets of experiments, each both in dry argon and in oil, allowed shearing at the interface and in the metal, and ploughing effects to be distinguished. The metals were: Al, Cr, Co, Cu, Fe, Mg, Mo, Ni, Re, Rh, Ti, W and Zr.
Sproles and Duquette (Wear 52 9 5 - 1 0 4 (1979)) have developed a technique using laser interferometry, for measuring slip amplitude to -+0.95/am: average sliding velocities ~'t the interface for each 1.9/am of sliding can also be calculated. The measurements are not affected by elastic deformation of the test fixture or minor vibrations in the laser and detector mounts. The paper also presents results of tests on 4130 steel which indicated that previously reported variations of fretting interface temperature closely follow the pattern of the instantaneous sliding velocity of the interface, as would be expected from frictional heating. The pattern of sliding velocity with time is regular from one cycle to the next. Poon and Hoeppner (Wear 52 1 7 5 191 (1979)) have carried out a fretting fatigue programme, using 7 0 7 5 T6 aluminium alloy, to determine
TRIBOLOGY international April 1979
103
statistically the relative roles of the mechanical and chemical factors in the mechanism of fretting. The results, supported by a fract0graphic analysis, indicate that the chemical factor plays a dominant role. Further work is underway to investigate the effect of environment (ie the chemical factor) at several stress levels.
Composite wear Eliezer et al (Wear 52 133 139 (1979)) have performed friction and wear experiments on tv¢o graphite fibrealuminium matrix composites and commercially pure copper and aluminium in a brake type friction machine. For the metals, the wear volume per braking cycle is proportional to the product of load and sliding distance, ie is in accord with both the adhesive and delamination theories of wear. With the composites, the wear volume is proportional to the product of load and sliding time, which cannot be explained by either of the wear models.
Gas bearing design An experimental and theoretical study at Leicester Polytechnic has aimed to ease the controversy concerning the relative merits 04"slot and orifice compensators for gas primal bearings. An interim report (Wear 51 137-145 (1978)) shows that slot entry at high eccentricity ratios gives greater load capacity, while orifice compensated bearings have great stiffness up to e = 0.35. Wear is published by Elsevier Sequoia SA, PO Box 851, 1001 Lausanne 1, Switzerland
Centralised lubrication Automatic centralised lubrication in general offers machine users a number of reasonably well documented advantages. Specific applications have not, in the past, been as well documented. Searey, in a paper in Lubrication Engineer, describes a system for automatic lubrication of the jourd-
Reprints are e s s e n t i a l •
In return we offer a generous salary, Company car, Superannuation F , n d and free BUPA membership.
Please write requesting application form to:The Personnel Office, Montedison U.K. Limited, 7/8, Lygon Place, Ebury Street, London, SWIW 0JR.
104
TRIBOLOGY international April 1979
f o r t h e c : o m p a n ) ' ttl~! w ~ n t s to d i s t r i b u t e i r n p a r t i , i [ c o r n m e n t o n its ac:tivitie.~, to p o t e n t i ~ l customers and clients
Although this position is based in London initial training will involve several months in Italy and a possibility of transfer to U.S.A. or Italy in 1980. The successful candidate, who should be aged between 30 and 40, should possess a sound marketing approach together with a chemical background. Knowledge of a foreign language would be an advantage although this is not essential.
Interlude Systems Ltd., Estover Road, Plymouth, Devon PL6 7PS, UK Central Lubrication, Engineering and General Equipment Ltd., Eley Estate, Edmonton, London N18 3DB, UK Lubrication Engineer is published by ASLE, 838 Busse Highway, Park Ridge, Illinois 60068, USA
Reprints of all articles in this j o u r n a l a r e a v a i l a b l e in quantities of 1O0 or m o r e
DESIGN LUBRICATION ENGINEER We are the U.K. Distributors for a major International Petrochemical/Fibre raw material producer and we are looking for a Design Lubrication Engineer with experience in high performance lubrication and sales/Technical service preference. This position will involve technical sales management for a unique series of PERFLUORINATED POLYETHER LUBRICATING OILS AND GREASES to high technology areas.
rinier and press section of a paper machine. Experience with the system has been excellent and a number of benefits are reported: Improved working conditions Reduced maintenance costs and labour costs Reduced production losses through extended bearing life and less unscheduled downtime. Two manufacturers have recently produced up-dated product information. Interlude have produced two brochures on their chassis lubrication systems and Central Lubrication have produced new catalogues, design manuals and technical brochures on their full range of central lubrication equipment.
•
f o r tt~e c : o r n p a n ) ' tt~at w a n t s to u p - d a t e its t e c h n i c a l staff o n n,~w techniques and new technologi~ s
F o r full d e t a i l s of p r i c e s ~!tnd a v a i l a b i l i t y of r e p r i n t s ,
p l e a s e w r i t e to
The Reprint Department, Westbury House, Bury Street, Guildford, Surrey, GU2 5AW, UK
102
not improve component reliability sufficiently to justify the possible increase in system cost, weight and complexity. It has also been presumed that free filters would clog more quickly, have a higher clean pressure drop and generally require more maintenance than currently used filters. It has been shown that these assumptions are not always correct and, recently, a 3/am filtration was selected for turbine engines powering advanced US helicopters. It has also been shown desirable to pre-filter lubricating oil through an extra time filter in filling systems in critical applications such as those in aircraft. Further information is contained in a 32-page report 'Effect of filtration on rolling-element-bearing life in a contaminated lubricant environment' by S.H. Loewenthal et al, reference T78 6747, available as microfiche £1.19 or reproduced paper-copy £2.80, from TechAlert, TRC, Orpington, Kent, BR5 3RF, UK*
Protecting hot surfaces Blades and other components in gas turbines are subjected to extremely harsh thermal conditions and require some surface protection system if premature failure is to be avoided. With efforts to improve turbine efficiency by increasing operating temperature, this poses increasingly difficult materials engineering problems. The problems and principles of high-temperature surface protection systems and recent developments are reviewed in a NASA report. The report gives details of the various coatings and deposition ntethods which are now available. Attention is concentrated on the gas turbine application, but many of the basic principles are applicable wherever metals are subjected to very hot gas flOWS.
In gas turbines, the primary concern is to protect alloys of nickel and cobalt from degradation by four interactive processes: oxidation, erosion caused by particulates, hot corrosion by impurities derived from the fuel or air, and thermal fatigue resulting from cyclic thermal stresses. The surface protection system has to resist or *Synopses provided by TechA lert. Remittances payable to Department o f Industry
TRIBOLOGY international April 1979
retard these processes while not causing any alloy reactions which would degrade their strength or ductility. The basis for high-temperature surface protection systems in gas turbines are alloys of the type MCrA1X: M can be one or more of Ni, Co or Fe; X denotes oxide scale adherence additives such as noble or reactive metals, such as Pt, Zr, Y or Si, or finely dispersed oxides, such as T h O 2 , Y203 or Z r O 2. The review outlines the protection mechanisms and discusses the selection and formation of the coating systems and their oxidation, hot corrosion and thermal fatigue performances. Three different types of system are discussed: aluminide coatings where the coating is formed by a diffusion reaction with the substrate; overlays where neither the formation nor the composition of the coating depends on a substrate diffusion reaction; and thermal barriers where an insulating coating, usually of stabilized ZrO2 is superimposed on a bond overlay coating. Coating deposition methods discussed include: the pack cementation process for aluminide coatings; physical vapour deposition; sputtering and plasma spraying for overlay coatings; and plasma spraying for thermal barriers. Current developments aimed at improving the effectiveness of the various coatings are reviewed. Further information is contained in a 17-page report: 'High temperature surface protection' by S.R. Levine, reference N78-17340, available as microfiche £1.19 or reproduced paper-copy £1.50, from TechAlert, TRC, Orpington, Kent, BR5 3RF, UK*
Longer-lasting grease A new grease lubricant, offering improved machine reliability and savings in maintenance costs, has been specified for use in US naval vessels. A 1974 report, recently released by the US Naval Ship Research and Development Center, describes simulated severe long-service life tests giving an indicated bearing life with the new grease of almost three times that with conventional greases. The grease was tested in deep-groove (Conrad-type) 75 mm bore, singleshield, precision (noise-tested) ball
beatings supporting a horizontal shaft. Tests were conducted at a shaft speed of 3600 rev/min (270 000 DN) with the bearings under an axial load of 4000N. Bearing outer ring temperature was set at about 93°C, slightly higher than would be expected in service. All the test bearings were stopped after 11 070 h successful running with the new grease. Four were then left running. One failed after 19 940 h and another failed after 20 450 h; the other two were sitll running successfully after 26 800 h. Test data lead to a conservative estimate of at least 11 000 hours as the life 90 percent of the bearings would be expected to exceed without lubrication failure using the new grease. In comparison equivalent bearing lives using two conventional greases were 4000 hours (90 per cent confidence limits of 3444 and 5297 hours) with one grease and 4230 hours (90 per cent confidence limits of 2963 and 6326 hours) with other. Tests of the greases on vertical shafts were underway when the report was being prepared. Further information is contained in a 28-page report 'Long-life grease performance in horizontal shaft rolling contact bearings for shipboard machinery' by L.G. Schneider and P. Lassovszky, reference AD-923 094, available as microfiche £1.19 or reproduced paper-copy £2.80, from TechAlert, Technology Reports Centre, Orpington, Kent, BR5 3RF, UK*
Solid lubricant synergisms Surprisingly little has been done to investigate the mechanisms responsible for the synergistic improvement of solid film lubricants by non-lubricant additives such as antimony trioxide (Sb203). Without such work, significant advances in solid film lubrication technology seem unlikely. A substantial contribution to filling this gap is now provided by a US Air Force study carried out to identify the mechanisms (chemical, mechanical and tribochemical) by which Sb2 O3 additives enhance molybdenum disulphide (MoS2) lubrication. Among the more important ffmdings are that the Sb203 additives: inhibit the oxidation of MoS2, especially in the range 300°C to 600°C; reduce the pressures required to form pellets; alter the morphology and chemistry of burnished pellet surfaces.
The report also indicates questions which will require further work and describes the design and construction of a friction tester for solid lubricant evaluation. Further information is contained in a 53-page report 'Synergistic mechanisms of solid lubricants' by R.S. Harmer and C.S. Passtano, reference AD-A054 741, available as microfiche £1.19 or reproduced paper-copy £4.10, from TechAlert, Technology Reports Centre, Orpington, Kent, BR5 3RF, UK*
Polymer wear Better understanding of polymer wear is provided by a report on a US Army contract. Wear tests were carried out by sliding a normally loaded polymer specimen (PVC, polychlorotrifluoroethylene or nylon) on a roughened mild steel surface. The weitr mechanism is determined by whether the surface asperities fully penetrate the polymer (real and apparent areas of contact equal) or whether the penetration is only partial (real area less than apparent area). With full penetration the polymer shears off at an angle to the surface which correlates directly with the polymer's energy to rupture and inversely with its wear rate. With partial penetration the wear data are directly related to the depth of penetration. This is a function of the polymer yield strength and the bearing area curve of the surface. Surface profile statistics are vital in wear prediction but it is important to ensure that the only parts of the surface considered are those that are actually in contact with the polymer.
Both the friction force in metal ploughing and groove height (corresponding to groove volume) decrease linearly with increasing ultimate shear strength. Metal grooving is primarily by plastic deformation with only occasional metal removal. The relation between the groove width D and applied load W is given by W = kD n ,
where n is a constant depending on the material, which satisfies Meyer's law. Further information is contained in a 25-page report 'Friction and wear of'metals with a single-crystal abrasive grit of silicon carbide - Effect of shear strength of metal' by K. Miyoshi and D.H. Buckley, reference T78 6312, available as microfiche £1.19 or reproduced paper-copy £1.50, from TechAlert, Technology Reports Centre, Orpington, Kent BR5 3RF, UK*
Fretting There is some confusion in the liter, ature over the influence of slip amplitude on fretting wear. It has been suggested that this is due to the difficulties in measuring slip amplitude accurately.
Further information is contained in a 6-page report 'Depth of penetration as a predictor of the wear polymers on hard, rough surfaces' by J.H. Warren and N.S. Eiss, Jnr, reference T79 843, available as microfiche £1.19 or reproduced paper-copy £1.50, from TechAlert, Technology Reports Centre, Orpington, Kent, BR5 3RF, UK*
Metal abrasion and shear strength A N A S A report provides new data on
the plastic deformation and removal of metals, and on the friction force in sliding in terms of shear strength. Sliding friction experiments were conducted with spherical silicon carbide runners on thirteen different metals, and with riders of the same metals sliding on silicon carbide. The
two sets of experiments, each both in dry argon and in oil, allowed shearing at the interface and in the metal, and ploughing effects to be distinguished. The metals were: Al, Cr, Co, Cu, Fe, Mg, Mo, Ni, Re, Rh, Ti, W and Zr.
Sproles and Duquette (Wear 52 9 5 - 1 0 4 (1979)) have developed a technique using laser interferometry, for measuring slip amplitude to -+0.95/am: average sliding velocities ~'t the interface for each 1.9/am of sliding can also be calculated. The measurements are not affected by elastic deformation of the test fixture or minor vibrations in the laser and detector mounts. The paper also presents results of tests on 4130 steel which indicated that previously reported variations of fretting interface temperature closely follow the pattern of the instantaneous sliding velocity of the interface, as would be expected from frictional heating. The pattern of sliding velocity with time is regular from one cycle to the next. Poon and Hoeppner (Wear 52 1 7 5 191 (1979)) have carried out a fretting fatigue programme, using 7 0 7 5 T6 aluminium alloy, to determine
TRIBOLOGY international April 1979
103
statistically the relative roles of the mechanical and chemical factors in the mechanism of fretting. The results, supported by a fract0graphic analysis, indicate that the chemical factor plays a dominant role. Further work is underway to investigate the effect of environment (ie the chemical factor) at several stress levels.
Composite wear Eliezer et al (Wear 52 133 139 (1979)) have performed friction and wear experiments on tv¢o graphite fibrealuminium matrix composites and commercially pure copper and aluminium in a brake type friction machine. For the metals, the wear volume per braking cycle is proportional to the product of load and sliding distance, ie is in accord with both the adhesive and delamination theories of wear. With the composites, the wear volume is proportional to the product of load and sliding time, which cannot be explained by either of the wear models.
Gas bearing design An experimental and theoretical study at Leicester Polytechnic has aimed to ease the controversy concerning the relative merits 04"slot and orifice compensators for gas primal bearings. An interim report (Wear 51 137-145 (1978)) shows that slot entry at high eccentricity ratios gives greater load capacity, while orifice compensated bearings have great stiffness up to e = 0.35. Wear is published by Elsevier Sequoia SA, PO Box 851, 1001 Lausanne 1, Switzerland
Centralised lubrication Automatic centralised lubrication in general offers machine users a number of reasonably well documented advantages. Specific applications have not, in the past, been as well documented. Searey, in a paper in Lubrication Engineer, describes a system for automatic lubrication of the jourd-
Reprints are e s s e n t i a l •
In return we offer a generous salary, Company car, Superannuation F , n d and free BUPA membership.
Please write requesting application form to:The Personnel Office, Montedison U.K. Limited, 7/8, Lygon Place, Ebury Street, London, SWIW 0JR.
104
TRIBOLOGY international April 1979
f o r t h e c : o m p a n ) ' ttl~! w ~ n t s to d i s t r i b u t e i r n p a r t i , i [ c o r n m e n t o n its ac:tivitie.~, to p o t e n t i ~ l customers and clients
Although this position is based in London initial training will involve several months in Italy and a possibility of transfer to U.S.A. or Italy in 1980. The successful candidate, who should be aged between 30 and 40, should possess a sound marketing approach together with a chemical background. Knowledge of a foreign language would be an advantage although this is not essential.
Interlude Systems Ltd., Estover Road, Plymouth, Devon PL6 7PS, UK Central Lubrication, Engineering and General Equipment Ltd., Eley Estate, Edmonton, London N18 3DB, UK Lubrication Engineer is published by ASLE, 838 Busse Highway, Park Ridge, Illinois 60068, USA
Reprints of all articles in this j o u r n a l a r e a v a i l a b l e in quantities of 1O0 or m o r e
DESIGN LUBRICATION ENGINEER We are the U.K. Distributors for a major International Petrochemical/Fibre raw material producer and we are looking for a Design Lubrication Engineer with experience in high performance lubrication and sales/Technical service preference. This position will involve technical sales management for a unique series of PERFLUORINATED POLYETHER LUBRICATING OILS AND GREASES to high technology areas.
rinier and press section of a paper machine. Experience with the system has been excellent and a number of benefits are reported: Improved working conditions Reduced maintenance costs and labour costs Reduced production losses through extended bearing life and less unscheduled downtime. Two manufacturers have recently produced up-dated product information. Interlude have produced two brochures on their chassis lubrication systems and Central Lubrication have produced new catalogues, design manuals and technical brochures on their full range of central lubrication equipment.
•
f o r tt~e c : o r n p a n ) ' tt~at w a n t s to u p - d a t e its t e c h n i c a l staff o n n,~w techniques and new technologi~ s
F o r full d e t a i l s of p r i c e s ~!tnd a v a i l a b i l i t y of r e p r i n t s ,
p l e a s e w r i t e to
The Reprint Department, Westbury House, Bury Street, Guildford, Surrey, GU2 5AW, UK