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홍정희,마이크데이,Hong, J.H.,Day, Mike The Korean Society for Fluid Power and Constructio 2012 드라이브·컨트롤 Vol.13 No.4
This paper explains how eliminating contamination from the manufacturing processes will lead to better product quality and hence the need for reworking, a trouble free commissioning period and greatly improved production efficiency. All of these will reduce costs and energy usage. It will also ensure that the product is delivered to the customer in a condition that will ensure improved reliability and longer life, again reducing both energy and other operating costs. Correctly designing the contamination control measures will achieve and maintain the level of fluid cleanliness that is required by the end user. The filter is critical to cleanliness management and should be selected with the same degree of thought and consideration as for other major components. This paper explains the role that Cleanliness Management plays in the reducing the carbon footprint of systems and processes by making them perform more efficiently for longer periods. It also examines two differing ways of selecting filters to incorporate the features of newer designs, and shows how significant savings in the costs of ownership can be achieved using these approaches.
Electrostatic Discharge in Hydraulic and Lubricating Applications
J. H. Hong(홍정희),Mike Day(마이크데이) 유공압건설기계학회 2013 유공압건설기계학회 학술대회논문집 Vol.2013 No.10
Electrostatic charge generation occurs in fluid systems as a result of friction between both the fluid and system components and also the hydraulic fluid and other fluids, notably air and additives. Electrostatic Charging (ESC) is a well-known problem in systems using hydrocarbon fluids, predominantly fuels and lubrication oils but less is known about its generation in hydraulic fluid power oils. In liquid hydrocarbon filtration, whether the charge generated on the fluid is positive or negative will depend on the fixed charge of the filter material and the fluid used. The paper explains that the new electrostatic dissipative (ESD) filter was developed to eliminate potential ESC problems in filtration of hydrocarbon fluids by preventing or significantly reducing both charge generation and its accumulation, and field trials showed successful performance of the ESD filter material, and correlated well to the laboratory tests.
홍정희(J. H. Hong),김한식(H. S. Kim),칼파루그(Kal Farooq) 유공압건설기계학회 2011 유공압건설기계학회 학술대회논문집 Vol.2011 No.6
Electro Hydraulic Control systems that control the flow of steam into the steam turbines, including such functions as turbine emergency trip, are a critical part of the power generation system. Malfunction of the fine servo valves that control steam control governor system is highly undesirable. These valves, by virtue of their very small operating clearances between the precision machined surfaces are very susceptible to malfunction when fluid suspended contaminant such as fine particles and semi-soft, gel-like material get into the clearance spaces. The contaminants wedge or form deposits on the valve surfaces such as spools, bores and orifices thus reducing the operating clearances, resulting in valve malfunction. In addition to deposits on valves the contaminant deposits on the small, last chance metal secreen filters, orifices, pumps, seals, heat exchanger and reservoir walls-resulting in a range of adverse consequences.
Electrostatic Discharge in Hydraulic and Lubricating Applications
J. H. Hong(홍정희),Mike Day(마이크 데이) 한국트라이볼로지학회 2013 한국트라이볼로지학회 학술대회 Vol.2013 No.10
Electrostatic charge generation occurs in fluid systems as a result of friction between both the fluid and system components and also the hydraulic fluid and other fluids, notably air and additives. Electrostatic Charging (ESC) is a well-known problem in systems using hydrocarbon fluids, predominantly fuels and lubrication oils but less is known about its generation in hydraulic fluid power oils. In liquid hydrocarbon filtration, whether the charge generated on the fluid is positive or negative will depend on the fixed charge of the filter material and the fluid used. The paper explains that the new electrostatic dissipative (ESD) filter was developed to eliminate potential ESC problems in filtration of hydrocarbon fluids by preventing or significantly reducing both charge generation and its accumulation, and field trials showed successful performance of the ESD filter material, and correlated well to the laboratory tests.
Component Cleanliness of Fluid Systems in Automotive and Hydraulics complying with ISO Standards
J. H. Hong(홍정희),Mike Day(마이크 데이) 유공압건설기계학회 2013 유공압건설기계학회 학술대회논문집 Vol.2013 No.6
As the presence of particulate contamination in the lubricant is a major cause of failures and short component service life in fluid systems, companies in a variety of industries are focusing attention in achieving and maintaining system cleanliness. The presence of machining and assembly debris in the fluid system at startup and during the initial running phase will cause a substantial increase in the wear rates of the system, further generation of large particles, with the consequential loss in performance and component life. It will also increase the probability of sudden and catastrophic failure of the system. To achieve clean components requires appropriate manufacturing, cleaning and measurement processes. Accurate assessment of the effectiveness of components and parts cleanliness is related to given contaminant extraction methods, analysis and data reporting, and ISO Standards are continually being developed to control procedures and implement a consistent cleanliness evaluation process. This paper explains the processes in these standards and explains how similar procedures have been adapted to suit the requirements of the above Industries. It also gives guidance and recommendations on the implementation of these standards, so that the best use can be made of them.
홍정희(J. H. Hong),마이크데이(Mike Day) 유공압건설기계학회 2012 드라이브·컨트롤 Vol.9 No.4
This paper explains how eliminating contamination from the manufacturing processes will lead to better product quality and hence the need for reworking, a trouble free commissioning period and greatly improved production efficiency. All of these will reduce costs and energy usage. It will also ensure that the product is delivered to the customer in a condition that will ensure improved reliability and longer life, again reducing both energy and other operating costs. Correctly designing the contamination control measures will achieve and maintain the level of fluid cleanliness that is required by the end user. The filter is critical to cleanliness management and should be selected with the same degree of thought and consideration as for other major components. This paper explains the role that Cleanliness Management plays in the reducing the carbon footprint of systems and processes by making them perform more efficiently for longer periods. It also examines two differing ways of selecting filters to incorporate the features of newer designs, and shows how significant savings in the costs of ownership can be achieved using these approaches.
Monitoring of Cleanliness Level in Hydraulic Systems ; Obtsining Reliable On-Line data
홍정희(J. H. Hong),마이크 데이(Mike Day) 유공압건설기계학회 2012 유공압건설기계학회 학술대회논문집 Vol.2012 No.6
Monitoring of system cleanliness levels and counting of particulate contaminant are fundamental to achieving hydraulic system reliability as any departure from the specified cleanliness level is often a precursor to future failures. On-line monitoring of cleanliness levels has the advantage of giving data both very quickly and accurately as environmental influences are eliminated. In this way, corrective actions can be promptly implemented. Most on-line instruments are sensitive to system conditions to a greater or lesser extent, but Automatic Particle Counters (APCs) working on light extinction principles are especially sensitive to the presence of optical interfaces caused by such conditions as fluid mixtures, emulsions, free water and air bubbles. These conditions give erroneous data and can result in drawing incorrect conclusions, wasting maintenance time and ultimately, reduced user confidence in cleanliness monitoring. This paper describes such conditions and shows how the correct selection of the analysis technique can result in reliable cleanliness level data.
홍정희(J. H. Hong),양재일(J. I. Yang),칼 파루그(Kal Farooq) 유공압건설기계학회 2011 유공압건설기계학회 학술대회논문집 Vol.2011 No.6
The resinous, soft material that tends to form sticky deposits, commonly referred to as "varnish", on metal surfaces inside the hydraulic and lubrication system is a difficult contaminant to filter out from the fluid with conventional particulate removal filters. By virtue of its softness and small size, the material squeezes thru the porous, fibrous matrix of the typical glass-fiber filter media used for particulate removal. Hydraulic systems using small clearance servo, proportional and solenoid flow direction control valves are especially susceptible to malfunction when the resinous, fluid suspended material forms deposits on the valve surfaces such as spools, bores and orifices thus reducing the operating clearances, resulting in valve malfunction. In addition to deposits on valves the varnish forming material deposits on metal screen filters, bearings, seals, heat exchanger and reservoir walls-resulting in a range of adverse consequences. The hydraulic control system that regulates the air blowing flow from the Turbine Blower at POSCO steel mill in Pohang city, Korea, uses a Spool type of Electric Solenoid valve and Z-Pipe type Solenoid valves that adjust the position of a dual cylinder to regulate the air flow in a tight range to obtain the laminar flow conditions of flow going to the heat blowing path. The solenoid valves make adjustments to the position of the cylinder based on a closed-loop feedback from sensors. The subject system that uses an ISO VG 46 hydraulic fluid was experiencing symptoms and problems associated with "varnish" type deposits. This paper discusses the sticking problemsof the solenoid valves the plant was experiencing and the treatment of the hydraulic fluid with a Pall engineered absorbent medium that solved the problem.
홍정희(J. H. Hong),마이크 데이(Mike Day) 유공압건설기계학회 2010 유공압건설기계학회 학술대회논문집 Vol.2010 No.6
In order to improve the life and reliability of fluid components used in the Automotive, Hydraulics and Aerospace industries, the cleanliness of the system parts and components before their assembly into the system is being addressed. The measurement of components and parts cleanliness is related to contaminant collection, analysis and data reporting and ISO Standard are continually being developed to control procedures. This Paper explains the processes in these standards and explains how similar procedures have been adapted to suit the requirements of the respective Industry. It also gives guidance and recommendations on the implementation of these standards, so that best use can be made of them.