摘要:

AbstractThe purpose of the investigation reported here was to determine whether or not a hydrostatic transmission can act as an alternative to a conventional one, and, if so, to ascertain to what extent the fluid type contributes to an improvement in the efficiency of the hydrostatic transmission. The results presented in this paper are derived from an experimental field test of the hydrostatic transmission of a belt conveyor. This belt conveyor is one part in an ore‐transport line at LKAB mining company in Kiruna. The hydrostatic transmission replaced a conventional transmission consisting of an electric motor, a belt drive and a gearbox. The hydrostatic transmission was operated using three different hydraulic fluids: Shell Tellus TX 68, a conventional mineral oil; Mobil SHC 526, a synthetic fluid; and Binol Hydrap II, a vegetable fluid. All fluids have the same ISO viscosity grade, VG 68.The measurements on the transmission show a 3% overall efficiency improvement when using vegetable and synthetic hydraulic fluids compared with the mineral oil. The current at the start of the transmission was reduced by a factor of 6, compared to that of the conventional transmission. The installed 110 kW electric motor was replaced with one of 55 kW. The test also showed that a closer study of all operating conditions, and a selection of components suited to the size of the load, can improve the overall efficiency of the hydrostatic transmissio

ISSN:0265-6582    

DOI:10.1002/jsl.3000170402

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

摘要:

AbstractSolutions of high molecular‐weight polymers, particularly polyoxyalkylene glycols (PAGs), are used widely in the heat treatment of metals known as ‘quenching’. This is mainly because of the non‐flammable nature of the polymer solution, compared with safety hazards associated with traditional mineral‐oil based quenchants. However, the use of PAG‐based quenchants for some heat treatment processes, particularly for slow cooling speeds, has been limited. This paper describes how, through an understanding of the quenching mechanism, the quench speed of PAG‐based quenchants can be slowed by the use of additives or controlling the conditions of operation. The paper also gives an overview of the experimental measurement of polymer quenching and the factors involved

ISSN:0265-6582    

DOI:10.1002/jsl.3000170403

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

摘要:

AbstractThe present paper presents the results of some research into the production of synthetic ester oils of mixed structure on the basis of citric acid (2‐hydroxy‐1,2,3 propane tricarboxylic acid) with beneficial tribological properties and potential biodegradability. Two series of unsymmetrical triesters have been synthesised by varying the molar relationship between branched aliphatic alcohols from C4to C13along with a special alcohol of a complex aliphaticaromatic structure, namely 2‐(o‐sec‐butyl)phenoxy‐ethanol. Based on this, it has been possible to obtain products with various properties. The introduction of the aromatic function into the structure of these triesters induces interesting features, and the natural source of the citric acid holds potential for having good ecological characteristics, which are intended to be the subject of furth

ISSN:0265-6582    

DOI:10.1002/jsl.3000170404

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

摘要:

AbstractCryogenic treatment of polytetrafluoroethylene (PTFE) has proved beneficial in improving the abrasive wear resistance of several polymers, and it was thus assessed in an adhesive wear mode, as well. Preliminary investigations on the effect of cryogenic treatment on the tribological properties, in adhesive wear mode, and mechanical properties of neat PTFE and it composites filled with bronze or short glass fibres (GF) were carried out. It was found that, although the improvement in the wear and friction performance of neat PTFE and a GF + PTFE composite was significant, no such positive effect was observed for the bronze + PTFE composite. On the contrary, this composite showed a deterioration in performance.The reason behind the improvement in the tribological behaviour of neat PTFE and the GF + PTFE composite could not be clearly understood. However, it was confirmed that, if the treatment adversely affected the mechanical properties, then the tribological performance also deteriorated. An examination of the worn surface of the material and the counterface disc using a scanning electron microscope revealed changes in the microstructure due to the treatment. It was also confirmed from these SEM studies that the compatibility of bronze and PTFE was very poor, which led to poor performance of the composite both in the untreated and the cryo‐treated form. Further detailed investigation and analysis of various materials and composites, however, are necessary to establish the utility of this techniqu

ISSN:0265-6582    

DOI:10.1002/jsl.3000170405

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

摘要:

AbstractA grease has two major constituents, namely, a lubricant, that performs the function of lubrication; and a gellant, that provides a solid continuous phase, occludes the lubricant, and gives apparent physical structure to the grease. Generally, the gellant is 5–30% and the lubricant 65–90%, additives and fillers making up the rest. In conventional greases, the gellant is a vegetable oil soap, and the lubricant is a liquid oil of petroleum origin or is a synthetic. Such greases have limited biodegradability, because the major constituent, i.e., the lubricant, is normally not biodegradable.In total vegetable oil grease, both the gellant and the lubricant are derived from vegetable oils, giving a grease of potentially high eco‐compatibility. Esters, dibasic acid esters, and alkylated esters of vegetable oil are known to be high‐quality lubricants. These can be used with soap stocks prepared from vegetable oils to give a grease of total vegetable oil origin.The vegetable‐oil based lubricants and soaps are prepared separately and combined in appropriate proportions to give a grease of the required specifications. Alternatively, esterification and saponification can be carried out simultaneously to give a grease of the desired specifications, where an alkali will be the catalyst for esterification, and reactant for saponification. In this paper, the process parameters, and kinetics of these simultaneous reactions are discussed. The results of experimental evaluation of some of these greases are also

ISSN:0265-6582    

DOI:10.1002/jsl.3000170406

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000170407

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000170408

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY

ISSN:0265-6582    

DOI:10.1002/jsl.3000170401

出版商:John Wiley&Sons, Ltd    

年代:2001

数据来源: WILEY