The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform
W.e. Bill Forsthoffer - One of the best experts on this subject based on the ideXlab platform.
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8 – Mechanical seals
Forsthoffer's Rotating Equipment Handbooks, 2020Co-Authors: W.e. Bill ForsthofferAbstract:Publisher Summary This chapter discusses the function and types of mechanical seals. Mechanical seals are commonly specified for centrifugal pump applications. The mating faces of each member perform the sealing. The mating surface of each component is highly polished and they are held in contact with a spring or bellows which results in a net face loading closure force. The amount of heat generated at the seal face is a function of the face loading and friction coefficient, which is related to material selection and lubrication. The simple seal system incorporates an orifice in the Flush line from the pump discharge to the mechanical seal. Its purpose is to limit the injection flow rate to the seal and to control pressure in the seal chamber. An indication of some causes of seal failures can be obtained while the seal is operating. Tandem mechanical seals are used in applications where the pumped fluid is toxic and/or flammable. They consist of two mechanical seals. The primary seal is Flushed by any selected seal Flush Plan. The back-up seal is provided with a Flush system incorporating a safe, low flash point liquid. The chapter discusses the high temperature product Flush system which is desirable to maintain the required margin between liquid vapor pressure and seal chamber pressure.
Stan Shiels - One of the best experts on this subject based on the ideXlab platform.
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The ( B-K ) factor in mechanical seal life
Stan Shiels on Centrifugal Pumps, 2020Co-Authors: Stan ShielsAbstract:Correct application of a mechanical seal demands a study of the pump hydraulic performance and impeller design. The basic design of a mechanical seal usually permits variations in balance ratio, through changes in seal face size and shape. Lower balance ratios are chosen where the differential pressure across the seal faces is high; higher balance ratios where this differential pressure is low to moderate.. It is recommended that the correct balance ratio should match the projected seal cavity pressure. Also, Flush rate and Flush Plan can control seal face cooling to avoid too high or too low seal face pressure factor values. The study of each individual pump application is necessary before a seal can be optimized. Pump discharge pressure must be considered when deciding on the seal Flush Plan and respective Flush piping orifice sizing or other means of controlling Flush pressure. This permits adequate seal cavity temperature margin, and sufficient seal face cooling, without excessive seal cavity pressure. In addition, while Planning high pressure or high temperature seal application, it is recommended to consult a mechanical seal engineer.
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Understanding the essentials of centrifugal pump reliability
Stan Shiels on Centrifugal Pumps, 2007Co-Authors: Stan ShielsAbstract:Publisher Summary The most common issues that impact centrifugal pump reliability are—hydraulic compatibility, pump mechanical design, installation from grouting to piping design, mechanical seal design and application, bearing design and lubrication, start-up and operation, and maintenance standards. This chapter addresses these issues. Proper attention to any one individual area that impacts centrifugal pump reliability may result in incremental improvement in length of satisfactory service between repairs. Also, mechanical seal manufacturers today have developed a variety of excellent mechanical seal designs, such that most centrifugal pumps can be satisfactorily sealed at their shaft by proper selection and application of a standard seal type. Some difficult applications may require custom designed seals. The success of the mechanical seal rests with the following: optimization of the seal cavity; the selection of the optimum seal type for the type of pump and the service; the selection of the correct seal Flush Plan; proper start-up or commissioning procedures; and proper installation and maintenance.
Deng Zong-hua - One of the best experts on this subject based on the ideXlab platform.
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Design improvements on mechanical seals of high-temperature heat pumps
Modern Machinery, 2020Co-Authors: Deng Zong-huaAbstract:In the process of reforming the mechanical seals applied on high-temperature heat pumps,many seal manufacturers have resorted to the combination of a single welded metal bellow seal and an API Plan21 Flush Plan,due to its low cost,simple construction and great extension of a seal's service life.It becomes a recommended and popular sealing solution among seal manufacturers.However,this article points out the grievous security risk hidden behind the solution.It argues that security should be put at first place and emphasizes correct understanding and application of seal types and auxiliary systems recommended in API 682,to avoid fatal leakage accident of the high-temperature heat pump seals.
L. Fillaudeau - One of the best experts on this subject based on the ideXlab platform.
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Metrological performances of fouling sensors based on steady thermal excitation applied to bioprocess
Food and Bioproducts Processing, 2019Co-Authors: Y. Boukazia, Guillaume Delaplace, M. Cadé, F. Bellouard, M. Bégué, N. Semmar, L. FillaudeauAbstract:Abstract Food and industrial bioprocesses are impacted by (bio)fouling which generates failures from reduction of process efficiency (ex: reduction of heat transfer coefficient) up to health risk issue (e.g. biofilm formation). In present work, 3 fouling sensors based on a thermal excitation (steady thermal regime) were developed and described. These sensors were designed with different technologies (macro structure and Micro-Electro-Mechanical-Systems MEMS), geometries (intrusive cylindrical, Flush Plan) and packaging (presence or absence of cover panel) and compared. Laboratory setups were designed to characterize sensor responses under controlled operating conditions in batch and continuous process including clean condition and using layers of adhesive tape to simulate fouled conditions. Thermal responses from excitation under steady thermal regime at different heat flux were linearized then discussed as function of technology, geometry and packaging impacts. Packaging heat resistance, response times, efficient heat flux, and quantification of fouling were investigated. Finally, metrological limits were identified.
Y. Boukazia - One of the best experts on this subject based on the ideXlab platform.
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Metrological performances of fouling sensors based on steady thermal excitation applied to bioprocess
Food and Bioproducts Processing, 2019Co-Authors: Y. Boukazia, Guillaume Delaplace, M. Cadé, F. Bellouard, M. Bégué, N. Semmar, L. FillaudeauAbstract:Abstract Food and industrial bioprocesses are impacted by (bio)fouling which generates failures from reduction of process efficiency (ex: reduction of heat transfer coefficient) up to health risk issue (e.g. biofilm formation). In present work, 3 fouling sensors based on a thermal excitation (steady thermal regime) were developed and described. These sensors were designed with different technologies (macro structure and Micro-Electro-Mechanical-Systems MEMS), geometries (intrusive cylindrical, Flush Plan) and packaging (presence or absence of cover panel) and compared. Laboratory setups were designed to characterize sensor responses under controlled operating conditions in batch and continuous process including clean condition and using layers of adhesive tape to simulate fouled conditions. Thermal responses from excitation under steady thermal regime at different heat flux were linearized then discussed as function of technology, geometry and packaging impacts. Packaging heat resistance, response times, efficient heat flux, and quantification of fouling were investigated. Finally, metrological limits were identified.