Reducing the risk of fires in large reciprocating air compressor systems

A review of the background to selecting and testing reciprocating air compressor lubricants as regards their carbon forming tendencies is given in this paper. The results of field trials of a synthetic hydrocarbon type oil and the role played by the volatility of this lubricant in reducing carbon deposits are discussed.     

Lubrication characteristics between the vane and the rolling piston in a rotary compressor used for refrigeration and air-conditioning systems

The rolling piston type-rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness and high-speed operation. The present analysis is part of a research program directed toward maximizing the advantages of refrigerant compressors. The study of lubrication characteristics in critical sliding components is essential for the design of refrigerant compressors. Therefore, theoretical investigation of the lubrication characteristics of a rotary compressor used for refrigeration and air-conditioning systems was studied. The Newton-Raphson method was used for the partial elastohydrodynamic lubrication analysis between the vane and the rolling piston of a rotary compressor. The results showed that the rotational speed of a shaft and the discharge pressure significantly influence the friction force and the energy loss between the vane and the rolling piston.     

空调压缩机制冷量测量及其不确定度分析

对空调用压缩机制冷量的测试原理及方法进行了介绍，并对引起测试不确定度的因素及评定方法进行了分析研究。     

活塞空压机站房的噪声控制探讨

分析了活塞式空压机站房噪声产生机理,并提出了相应的噪声控制措施和对策。     

Lubrication characteristics of a rotary compressor used for refrigeration and air-conditioning systems (the influence of alternative refrigerants)

The rolling piston type rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness and high-speed characteristics. However, it is necessary to develop alternative refrigerants that can guarantee environmental protection. In addition, advanced refrigerant compressors must be further developed to overcome the compatibility problems inherent in refrigeration and air-conditioning systems. The refrigerant compressor is the most important mechanical component, which determines the performances of refrigeration and air-conditioning systems. Therefore, we theoretically investigated the lubrication characteristics of the rotary compressor currently used in both refrigeration and air-conditioning systems with an alternative refrigerant. In the theoretical investigation, the Runge-Kutta method is used to analyze the behavior of a rolling piston in the rotary compressor. Subsequently, the Newton-Raphson method is used, which provided good performance in the analysis of the elastohydrodynamic lubrication of the line contacts between a rolling piston and a vane in the rotary compressor. The results demonstrate that the alternative refrigerants influence the friction force and the energy loss between the vane and the rolling piston.     

Wear and friction of synthetic esters in a boundary lubricated journal bearing

This study concerns the case of a slow intermittent motion, conformal contact, high load bronze journal bearing against a hardened steel shaft lubricated in an oil bath at a temperature about of 13 °C. Three synthetic esters were used: one pure and two formulated ones. Worn surfaces were examined using SEM-EDS to determine the wear mechanism. The tested lubricants were examined using ICP-AES to identify the elements present.The results show the wear rate, friction and temperature in the subsurface of the journal bearing material. An initial bronze–steel contact develops into a copper–copper contact along the sliding distance. Wear element concentration in the oil and friction surfaces departs from the elementary concentration in the journal bearing bronze base material. The copper layer thickness depended on additives in the synthetic esters, load and wear rate.     

Dynamic characteristics of a hydrostatic journal bearing

The results of experimental investigations into the performance of a six-pocket hydrostatic journal bearing subjected to a range of dynamic loads are presented. The bearing performance was studied in terms of the load-carrying capacity and oil-film stiffness. The experimental results show that the test bearing has a better load-carrying capacity under dynamic load than under static load and that the load-carrying capacity and stiffness of the bearing are only limited by its mechanical strength.     

6M40往复活塞压缩机轴瓦烧研故障处理

分析了3台6M40往复活塞压缩机轴瓦、止推环烧研的原因,提出正确处理问题的方法,为今后处理此类难题提供了宝贵经验。     

Performance characteristics of a capillary-compensated hydrostatic journal bearing

Results are presented of an extensive experimental investigation into the performance of a six-pocket hydrostatic journal bearing with pockets of non-uniform depth subjected to a range of static loads. Lubricating oil was supplied, at pressures of up to 8.957 MN m^?2 (1300 Ibf in^?2), to capillarytype restrictors, connected to the six pockets in the bearing. The bearing had an $\text{L}\text{D}$ ratio of unity and operated with a journal rotation ranging from zero to 2000 rev min^?1.The measured load capacity and the stiffness characteristics indicated that bearings of this type had a significant load capacity which was limited by the bending of the shaft. The load capacity increased with speed at low supply pressures, but decreased slightly with increasing speed at higher supply pressures. The stiffness increased with eccentricity ratio except at low supply pressures. Film pressure surveys aided the elucidation of some of the bearing performance characteristics.     

往复压缩机故障诊断专家系统知识库的构建

分析了往复压缩机的故障表现形式，提出了在往复压缩机故障诊断专家系统中采用广义故障树知识表示方法，介绍了簇复压缩机故障诊断专家系统知识库的组成及其功能和特点。     

A procedure for evaluating the positioning accuracy of reciprocating friction drive systems

The dynamic characteristics of stick-slip motion in reciprocating friction drive systems are investigated under dry contact using a 0.45% carbon steel pair. Based on this dynamic analysis, the stick-slip motion can be eliminated under certain experimental conditions depending upon driver speed, normal load and spring constant. The effects of normal load, driver speed, and spring constant on the positioning accuracy of the reciprocating friction drive system are examined under harmonic oscillation without stick-slip motion. Results show that at very low spring constants, the slip increases with increasing driver speed such that higher normal load has better positioning accuracy or smaller slip than does lower normal load. However, at high spring constants and high normal loads, there exhibits severe wear or peak at two limit positions on the sliding region. As a result, smaller normal loads have a better positioning accuracy than larger normal loads due to severe wear at high normal loads.     

往复压缩机密封材料和结构的优选与优化

对3台4RDS往复压缩机组因填料和刮油环密封泄漏难以保障机组安全运行的问题,进行了填料和刮油环密封材料的优选和其密封结构的优化。     

往复活塞式空压机变频控制的技改方法

该文以冶金工业中普遍使用的D-100/8-e3型往复活塞式空压机为实例,论述了往复活塞式空压机的自动化变频控制技改方法,以及实施变频控制技改技术后,所达到的显著节能降耗效果。     

Load and flow characteristics of a capillary-compensated hydrostatic journal bearing

A theoretical analysis of load and flow characteristics of a capillary compensated oil-lubricated externally pressurized journal bearing having four rectangular recesses is presented. The analysis is based on an exact solution of the pressure distribution over the bearing sill area and has been made for two configurations of loading, through the centre of any recess and through the centre of the circumferential sill between any two recesses. The influence of circumferential sill length and intensity of compensation on the load carrying capacity and the flow requirement is shown. Theoretical analysis and experimental results are compared.     

A feature extraction method based on HLMD and MFE for bearing clearance fault of reciprocating compressor

According to the nonlinearity, nonstationarity and multi-component coupling characteristics of reciprocating compressor vibration signal, a feature extraction method based on hermite local mean decomposition (HLMD) and multiscale fuzzy entropy (MFE) is proposed for the diagnosis of reciprocating compressor oversized bearing clearance faults. Firstly, aiming at the strong nonstationary characteristic of vibration signal, a novel HLMD algorithm was given by using the monotone piecewise cubic hermite interpolation (MPCHI) instead of cubic spline interpolation (CSI) to construct the envelopes. Secondly, HLMD was performed on the vibration signals in each state and a series of PF components are produced, and the highlighted PF components which contain the main information of fault state were chosen with the correlation coefficient. Thirdly, MFE of the selected PF components were calculated to form the eigenvectors matrix, and the eigenvectors which have the best divisibility were extracted based on the average euclidean distances of each scale factor. Finally, four bearing clearance fault states were extracted by the proposed method, and taken SVM as a pattern classifier, the faults were diagnosed accurately. Furthermore, the comparison of recognition results with other three feature extraction methods demonstrates the superiority of this method.     

活塞压缩机用滑动轴承的摩擦磨损与润滑分析

对滑动轴承中的磨损与摩擦进行了分析，提出了相应对策。     

Impact of high pressure and shear thinning on journal bearing friction

For the study of mixed lubrication in journal bearings, this paper employs a combined experimental and simulative approach. Extensive measurements on a journal bearing test rig with a low viscosity 0W20 multi-grade lubricant provide a solid basis which is complemented by experimental lubricant data that is measured under high pressure and high shear rates. In this paper, this data is used to investigate the impact of the piezoviscous effect and the non-Newtonian lubricant properties on the friction power losses in journal bearings over a wide range of dynamic loads and shaft speeds.In particular, this work seeks to predict the friction power losses for journal bearings under both moderate (50 MPa peak load) and high dynamic loads (100 MPa peak load) using the recently presented accurate numerical method (Allmaier et al., 2011 [1], Allmaier et al., 2013 [2]). From the direct comparison to the experimental data a key finding is that the simulation conforms very closely to the measured data. To be more exact, the agreement lies within the measurement uncertainty.Following this result, the influence of the often neglected piezoviscous effect and the non-Newtonian lubricant rheology is investigated. We conclude that both the piezoviscous effect and the non-Newtonian behaviour are essential to describe the lubrication with multi-grade lubricants in journal bearings. Only the consideration of both properties describes the experimental data very accurately over the entire range of operating conditions studied.     

Nonlinear dynamic characteristics of geared rotor bearing systems with dynamic backlash and friction

Effects of the friction and dynamic backlash on the multi-degree of freedom nonlinear dynamic gear transmission system, which incorporate time varying stiffness, are investigated. Firstly, the relationship between gear central distance error and backlash is deduced and the dynamic backlash is defined, subsequently a multi-degree of freedom nonlinear dynamic gear transmission system is developed with dynamic backlash, friction and time varying stiffness. The nonlinear dynamic system is solved by the Runge-Kutta method. The results show that the friction force may enlarge the displacement magnitude and affect the high frequency parts significantly in frequency domain at low speed. But the RMS of the steady response is reduced on the effect of friction. The difference between the constant backlash and the dynamic backlash models is also discussed. The system may enter into previous chaotic motion due to the effect of dynamic backlash. Finally, no impact motion, single-side impact motion and double-side impact motion are also predicted in the new dynamic backlash model.     

Dynamic characteristics and stability of a journal bearing in a non-laminar lubrication regime

A mathematical model to determine the stiffness and damping coefficients and the stability limit curves of a journal bearing in a non-laminar lubrication regime is described. The results show the flow regime influence on the dynamic characteristics of cylindrical bearings and on the stability of a rigid rotor on rigid supports.     

往复压缩机组状态监测系统开发

往复压缩机组状态监测系统的开发，主要是针对机组的运行特点和现场要求而设计的，通过对机组进行状态监测，可以实时掌握机组运行状态和变化趋势，为实现预知维修及机组的高效运行提供了可靠的保障。