The pump affinity laws provide a useful way to estimate the effect of changes in either the revolutions per minute (rpm) or the diameter of the impeller on a pump’s performance. In this article, Roy C. E. Ahlgren, discusses why these laws can be better used to predict performance in some cases as opposed to others. Using an example, he demonstrates how the pump affinity laws predict actual performance with better accuracy at variable rpms than after trimming the impeller. In addition to better predictions when efficiency changes are smaller, the affinity laws assume geometric similarity and noncavitating pump operation with cold water. Finally, the affinity laws cannot take into account system curve, which also affects pump efficiency. The article includes figures showing several curves and tables of curve estimates.
Although a far cry from their counterparts of the 1970s, solar heating systems still present a significant up-front expense and can be less than aesthetically pleasing. Both cost and design improve as owners move toward green building and as architects incorporate solar components into more projects. This article presents the basics of solar-powered hot water heaters, which differ from traditional water heaters primarily in their power source. Major components include solar collector(s), circulation systems, storage tanks, a backup heating system, and control system. Direct systems (open loop) circulate domestic water between collectors and storage tanks. Direct systems can be downdrain or recirculating. Indirect systems (closed loop) circulate liquid (water, glycol) as a heating medium. Depending on their components, indirect systems can be more expensive and require more maintenance, but also have a number of advantages. Web-based resources are presented, along with a checklist including design criteria, types of systems, installation considerations, and mounting systems.
An ever-growing number of considerations that apply to storm water system design have greatly increased the complexity of the task. Design criteria, including local codes, climatic conditions (such as rainfall rate), and relevant building construction details must be determined first. Careful upfront work will help avoid misapplications and undersizing the system. The large-diameter pipe required for storm water systems can be problematic for horizontal routing designs. Suggestions for solving this problem are presented. Vertical leaders, overflow drainage, wall and floor cleanouts at the base of the riser, and storm and sanitary discharge into sewers are also discussed. Consultation with the structural engineer, civil engineer, and architect can ensure that both performance and aesthetic concerns are addressed. A detailed checklist accompanies the article.
Water is everywhere. One might think water from the tap that is clear and tastes all right is pure, but it is not enough so for laboratory use. Water picks up pollutants when it touches the ground?s surface and minerals when it permeates the ground. It also contains dissolved gases and dirt from the air. Contaminants that might be found in water include particulates, dissolved inorganic solids and gases, dissolved organics, micro-organisms, and pyrogens. Standards for laboratory pure water are published by several scientific, medical, or other groups. The National Committee for Clinical Laboratory Standards, which is now known as the Clinical and Laboratory Standards Institute, lists four categories, from the purest to water with certain contaminants removed. When the type of water needed is determined, a process can be set up to create it. They include reverse osmosis, filtration, and electrodialysis. The various processes are explained, and there is an accompanying checklist for design process, flow rates, distribution, distribution piping, storage tank, water hardness classifications, filtration, commissioning, pipe materials, and validation. Attached is a water pipe sizing table.
Compressed air, used in a myriad of industrial and commercial applications, is costly to manufacture, but the tools that it runs have numerous advantages over those powered by other energy sources. A well-designed compressed air system reduces energy costs, maintenance requirements, and equipment failures while increasing production efficiencies. James E. Stenqvist discusses system layout, recommending a loop design over a dead-ended tree design for greater efficiency, and detailing the loop design advantages. The main components of any compressed air system are the air compressor, compressed air dryer, and compressed air receiver. Each of these components is discussed according to function and available types. The last part of the article is given over to a listing of checks and tests that should be performed on the system at startup. Design standards for compressed air systems are listed. The article includes a full-page design checklist.
Olympus NDT, a global innovator in nondestructive testing instruments, is proud to announce the publication of NDT expert E. A. Ginzel’s Automated Ultrasonic Testing for Pipeline Girth Welds. This 366-page book provides an overview of the principles of automated ultrasonic testing (AUT) of girth welds, and explains the many parameters that influence the results of these inspections. Ginzel discusses some of the more experimental aspects of the process including sizing and acceptance criteria, and examines basic AUT concepts as applied by the major players in the industry and considers future enhancements.
This book provides a fundamental treatment of engineering hydraulics. It is intended to bridge the gap between basic principles and techniques applied to design and analysis of hydraulic engineering systems. This text exposes students to many problems commonly encountered in practice, various solution scenarios (e.g., design formulas, tables, and computer software) that are written by one of the largest commercial vendors of hydrology and hydraulics software.
This book serves as a training tool for individuals in industry and academia involved with heat transfer applications. Although the literature is inundated with texts emphasizing theory and theoretical derivations, the goal of this book is to present the subject of heat transfer from a strictly pragmatic point of view.
The book is divided into four Parts: Introduction, Principles, Equipment Design Procedures and Applications, and ABET-related Topics. The first Part provides a series of chapters concerned with introductory topics that are required when solving most engineering problems, including those in heat transfer. The second Part of the book is concerned with heat transfer principles. Topics that receive treatment include Steady-state Heat Conduction, Unsteady-state Heat Conduction, Forced Convection, Free Convection, Radiation, Boiling and Condensation, and Cryogenics. Part three (considered the heart of the book) addresses heat transfer equipment design procedures and applications. In addition to providing a detailed treatment of the various types of heat exchangers, this part also examines the impact of entropy calculations on exchanger design, and operation, maintenance and inspection (OM&I), plus refractory and insulation effects. The concluding Part of the text examines ABET (Accreditation Board for Engineering and Technology) related topics of concern, including economies and finance, numerical methods, open-ended problems, ethics, environmental management, and safety and accident management.
This is a comprehensive reference source on practical applications of plastic analysis for a wide scope of structures used in marine and other industries. The book is addressed to virtually all structural engineers involved in design, stress analysis, research, rule development, and advanced academic studies in shipbuilding, offshore and other fields.
1055 pages ♦ ISBN 0-9742019-2-8 ♦ Hard Cover
Rapra’s Practical Guide to PVC is packed with information for everyone working with PVC. It provides comprehensive background on the resins and additives, their properties and processing characteristics, as well as discussion of product design and development issues.
This book will be of interest to raw materials suppliers and processors or end-users of PVC, as well as anyone with a general interest in this versatile material.