New at PipingDesign.com: 04 November 2000

Flow of Fluids Through Valves, Fittings, and Pipes

[The publication and/or software version of this long-time favorite can now be ordered from

<a href="http://www.cranevalves.com/tech.htm">http://www.cranevalves.com/tech.htm</a>

the paper version is $30US, the software is $245US and up. Wasn't this publication free in the past? -PB]

Crane Technical Paper No. 410 (TP-410) is the quintessential guide to understanding
the flow of fluid through valves, pipe and fittings, enabling you to select the correct
equipment for your piping system.

Originally developed in 1942, the latest edition of Crane TP-410 serves as an
indispensable technical resource for specifying engineers, designers and engineering students.

TP-410 is published by Crane Valve Group (CVG), one of the world's leading
suppliers of valve products and services.

<a href="http://www.PipingDesign.com/pumps.html">http://www.PipingDesign.com/pumps.html</a> Pumps Galore! Dispelling Some Centrifugal Pump Fallacies PMEngineer.com

<<The field of centrifugal pump design and application is a specialized
one. It has its own set of terminology that, if not completely understood by a designer, can affect the performance of a centrifugal pump installation. Complete familiarity of this vocabulary as well as a solid working knowledge of fluid dynamics and pump design is essential to being a member of the pumpology clergy. To narrow the scope here, let's consider water at 70° F at sea level. To approach some centrifugal pump fundamentals, let's consider a few common myths:>>

Well Pumps
General Dennis J. Reimer Training and Doctrine Digital Library

<a href="http://www.PipingDesign.com/exchangers.html">http://www.PipingDesign.com/exchangers.html</a> Heat Exchangers For Ammonia
ASHRAE Journal Online

<<Ammonia has excellent thermodynamic properties, but part of this
potential will be lost if the heat exchangers have a low efficiency. The liquid chillers using HCFCs or HFCs have shell-and-tube heat exchangers using high-efficiency copper tubes, with sophisticated enhanced surfaces. Spectacular improvements have been achieved with this technology in the past decade. However, copper is not compatible with ammonia, and the traditional carbon steel shell-and-tube ammonia heat exchangers tend to be significantly larger than those used with other refrigerants. They also have a large refrigerant charge, which is not desired with ammonia for safety reasons. For new applications, this excludes the use of the traditional flooded evaporators or pump-fed in-tube recirculation systems. On the other hand, shell-and-tube D-X evaporators could not be used until recently because miscible oils were not available. This is why new solutions had to be found, implementing new combinations of materials, exchanger technologies (e.g., plate heat exchangers, or high efficiency tubes), new miscible oils, and expansion devices.>>

Controlling Shell and Tube Heat Exchangers Walter Driedger

<<Shell and tube heat exchangers are among the more confusing pieces of
equipment for the process control engineer. The principle of operation is simple enough: Two fluids of different temperatures are brought into close contact but are prevented from mixing by a physical barrier. The temperature of the two fluids will tend to equalize. By arranging counter-current flow it is possible for the temperature at the outlet of each fluid to approach the temperature at the inlet of the other. The heat contents are simply exchanged from one fluid to the other and vice versa. No energy is added or removed. Since the heat demands of the process are not constant, and the heat content of the two fluids is not constant either, the heat exchanger must be designed for the worst case and must be controlled to make it operate at the particular rate required by the process at every moment in time. The heat exchanger itself is not constant. Its characteristic changes with time. The most common change is a reduction in the heat transfer rate due to fouling of the surfaces. Exchangers are initially oversized to allow for the fouling which gradually builds up during use until the exchanger is no longer capable of performing its duty. Once it has been cleaned it is again oversized. >>

<a href="http://www.PipingDesign.com/steamtraps.html">http://www.PipingDesign.com/steamtraps.html</a> Steam Trap Troubles? Skip The Psychics
Mick Gerhardt

<<Give up on the psychic hotlines and don't even consider an exorcist
for solving your steam trap problems. There is a much more reliable way: Just understand how a steam trap works. That is the goal of this two-part series: to solve some of the confusion and mystery surrounding steam traps. With a little understanding of the purpose of a trap and how it works, you can eliminate much of the guesswork when deciding which type of trap to select, how to size it, and what will happen if it is not properly maintained.>>

<a href="http://www.PipingDesign.com/design.html">http://www.PipingDesign.com/design.html</a> Improving Air System Efficiency
R.S. Foss

<<When sizing pipe for a compressed air system, keep in mind that
without resistance to flow, there is no flow. Some pressure drop or some mass flow resistance is necessary. The amount of pressure drop only needs to be hundredths of a psig for the system to work, but it can be very high - and, therefore, inefficient - if you size the pipe incorrectly for the required flow and pressure. Both the energy efficiency and cost of the system are function of your decisions.>> Received on Fri Nov 03 16:31:00 2000