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Separation efficiency, contaminant capacity and operating power consumption are the three major factors in determining the performance of any separator. For an ideal separator, all unwanted material should be removed from the process fluid. In addition, the ideal separator must hold an infinite amount of separated contaminant and consume no power. Unfortunately, such an ideal separator is impossible to attain under the current laws of physics. However, the technology presented here represents a major step closer to these objectives. This paper introduces a new concept, orbital separation, for achieving high performance gas, liquid and solid separation. Orbital separation has nearly unlimited contaminant capacity and requires only a fraction of the input power required by other separation techniques. In this paper, the general principles of filtration and separation mechanics are reviewed. The orbital separation concepts are discussed and illustrated.

Three procedures for assessing the integrity of hydraulic hose/coupling connections were developed and shown to be effective methods for detecting hose failures induced by improper coupling connections. Each procedure's sole purpose is to detect one or two specific failure modes of hose assemblies. The development of these procedures arose from a need to quantitatively measure hose/coupling integrity. The three test procedures are the Mechanical/Hydrostatic Coupling/Hose Separation Test (FPRC-LH-S22), the Pneumatic Surge Test (FPRC-LH-S21), and the Progressive Leakage Test (FPRC-LH-S4). The results of each test yield not only failure modes, but a means for quantitative integrity rating. The Hose Assembly Rating is a test-dependent measure developed to scale all test results from 1 (poor) to 10 (excellent). This rating provides a means for expedient, direct comparison of test results. The use of these test procedures has proved invaluable.

The Standard Multipass (Beta) Filter Method (ISO 4572) has been a highly recognized and widely accepted test throughout industry since its introduction in the early 1970's. In the past decade, the Beta Method has indeed made a major contribution in assisting users in selecting filters to meet system design requirements. However, many complaints have been voiced by users that filters normally produce a lower particle removal efficiency under field applications than they do during laboratory tests. Research results from work carried out at the Fluid Power Research Center at Oklahoma State University indicate that the degradation of the filtration (Beta) ratio in service depends mainly on the filter's retentivity characteristic. This paper highlights the theoretical basis of the Epsilon Rating Method and the concept of retentivity. Most important, the paper uses these concepts to correlate filter performance between laboratory tests and field operation.

Sievability and separability are two major criteria which have been used in the past to appraise the performance of filters. Although both criteria have significance in rating filters, it has been demonstrated in practical applications that such ratings cannot reflect the entire spectrum of filter performance. Test data obtained from more than 1200 different filters tested in the past decade at the Fluid Power Research Center at Oklahoma State University indicate that two major intrinsic filtration parameters must be addressed to appropriately and accurately assess the characteristics of a filter. They are separability (power to capture) and retentivity (power to retain). The Epsilon Rating Method was developed from the Elutivity Theory, which considers the separability (Beta Filtration Ratio), the retentivity (Delta Ratio used to express the degree of particle desorption or caking) and system operating parameters.

As a result of the advancement of two significant test procedures - the Multi-Pass Test for Filters and the Contaminant Sensitivity Test for Components, a totally new filter selection method has evolved. This method considers the severity of the application, the sensitivity of the components, and the particle capture capability of a filter. The paper introduces for the first time a filter selection chart concept which reveals the influence of operating pressure, contaminant ingression, and desired service life on the selection process. Emphasis is placed on user-oriented information, and the type of charts which component manufacturers could supply the user as well as the type of charts the filter manufacturer could supply are illustrated.

The contamination level of the fluid within a hydraulic system is a reflection of not only the particle removal capability of the filter element, but also the contaminant ingression characteristics of the system. Furthermore, the amount of contaminant permitted to enter the fluid past exclusion devices has a direct influence on the filter requirements-separation efficiency and capacity. Thus, without some means of establishing the effectiveness of contaminant exclusion devices, no realistic analysis can be made regarding the contamination level of a hydraulic system. This paper presents the analytical expressions that can be used to describe rigorously the contamination control of a hydraulic system. The importance of contaminant ingression is dramatically illustrated by realistic test results. The correlation of the theoretical considerations with characteristic field conditions is accomplished using the results of a wiper seal study.

The multipass filtration performance test which has recently gained industry-wide support offers many fundamental ways of describing the performance characteristics of fluid power filter elements. Some of these descriptions are uniquely qualified to provide the system designer with a practical technique for appraising the capability of filter elements. Important appraisal parameters of a filter element which must be considered by a designer are particle separation capability, contaminant capacity, and pressure loss. In order to specify a filter element properly for a given application, the requirements for the appraisal parameters must reflect the needs of the system components. A practical and fundamental description for the performance of fluid power filters will incorporate appraisal parameters which can be related to the demands of such system components.

The paper presents a comprehensive treatment of the essential considerations involved in measuring the noise-generating characteristics of hydraulic components. The need for the reduction of noise levels for all types of hydraulic machinery is discussed from the manufacturer's point of view. The mechanical and fluid dynamic aspects associated with hydraulic components which create undesirable and damaging noise levels are described. Special emphasis is placed on quantitative methods for establishing and comparing noise levels of operating hydraulic components. A cursory review of the necessary facility requirements and measuring techniques is included.

A new method of correlating hydraulic component contaminant tolerance levels with hydraulic filtration performance has been developed using a cleanliness level chart. The chart provides a means of expressing contamination levels from particle count data. Methods are discussed for deriving component tolerance levels and rating filter elements on the basis of their efficiency characteristics. The correlation achieved enables the designer to establish the performance, reliability, endurance, and ultimate life of the hydraulic equipment.