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Consider a typical ANSI-dimensioned 1x1.5-6 pump, as discussed in the P&S August article. The performance curve showed the BEP flow at around 100 gpm. The ANSI designation 1x1.5 means that the discharge flange is 1 in and suction 1.5 in. Why and how do manufacturers select such dimensions for a particular flow rating? Why did they not select and base their performance coverage charts on a 3x4-8 size for the 100 gpm?
About 900 years before Newton formulated his universal gravitational theory, the Greek philosopher Aristotle espoused something different. He believed that all things had a natural place in the universe, so any object that fell to the earth did so because it had a "need" to return to its natural place. He further theorized that heavier objects would fall faster than lighter ones because they had an even greater need to return. We know now that his theory was a bit off the mark, but had he adapted it to corrosion, it could have described the process quite well.
If any silver linings exist for the economic crisis that has gripped the United States since last summer, one is the heightened public and governmental awareness about the nation's need for infrastructure improvements-a situation that American industry had watched grow without proper attention in recent years.
Materials expand when heated and contract when cooled. Pipes are not immune to these laws of nature, so they will also expand and contract with varying temperature.
With production time and cash flow at an all time premium, more companies are looking for time and cost saving alternatives to replacing slightly damaged assets.
Have you ever wondered why the pressure exerted by a column of liquid has absolutely nothing to do with its volume or, for that matter, the geometric shape of its container?
Two decades ago, EST Associates, Inc. started operations in Needham, Mass., to provide the New England area with environmental sampling and related monitoring services.
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If any silver linings exist for the economic crisis that has gripped the United States since last summer, one is the heightened public and governmental awareness about the nation's need for infrastructure improvements-a situation that American industry had watched grow without proper attention in recent years.
Have you ever wondered why the pressure exerted by a column of liquid has absolutely nothing to do with its volume or, for that matter, the geometric shape of its container?
Two decades ago, EST Associates, Inc. started operations in Needham, Mass., to provide the New England area with environmental sampling and related monitoring services.
Last month, we discussed applications of low head axial flow pumps ("Field Testing: Theory vs. Reality," Pumping Prescriptions, May 2007). Knowing your system is very important for these types of units. For example, consider a recent application where neglecting the system caused problems.
We will start with the basic formulas to calculate the velocity through the pipe of a given inside diameter D, and flow, Q.
New heat activated epoxy-based materials are now being used to repair leaking and corroded pipe work when operations are unable to shut down.
Industrial processes that manufacture, transfer, and distribute a variety of liquefied natural gases, from propane to oxygen to ammonia, require components to protect both the piping system and the pipe supports from the extremely cold temperatures. Pipe supports and piping that are not insulated may become brittle and crack, posing high risk to the piping and structural components.
This past summer I received a suggestion from a Pumps & Systems reader to discuss siphons and their effect on pump head and pipeline flow. If you are like me, your first experience with one of these devices probably led to your first - and hopefully last - taste of gasoline. The siphon is an example of a natural and extremely simple machine that we take advantage of daily.
Columns and Blogs
In this multi-part series, we will investigate several aspects of centrifugal pump efficiency.
First of Five Parts
Since the original publication of this draft standard in the January 2008 issue of Pumps & Systems, I have received feedback, encouragement, numerous questions and criticism. The draft listed three basic levels of repair.
The McGraw-Hill scientific dictionary [5] states that a volute is "a spiral casing for a centrifugal pump... designed so that speed will be converted to pressure."
