One of the important ingredients for making and keeping a reliable electrical connection is clean contact surfaces. When initial contact is made between electrical contact surfaces, no matter how smooth and level the surfaces, only a few high points touch. As the contact force increases, more points make contact until at optimum force most of the metal-to-metal contact has been accomplished. Contact theory tells us that these points are actually cold welds.

Cavitation means that cavities are forming in the liquid that we are pumping. When these cavities form at the suction of the pump several things happen all at once. The cavities form for five basic reasons and it is common practice to lump all of them into the general classification of cavitation. This is an error because we will learn that to correct each of these conditions we must understand why they occur and how to fix them.

Bearing life is defined as the length of time, or the number of revolutions, until a fatigue spall of a specific size develops. This spall size, regardless of the size of the bearing, is defined by an area of 0.01 inch2 (6 mm2). This life depends on many different factors such as loading, speed, lubrication, fitting, setting, operating temperature, contamination, maintenance, plus many other environmental factors. Due to all these factors, the life of an individual bearing is impossible to predict precisely.

The American Petroleum Institute (API) issues guide lines to help petroleum people select and then pipe various types of controls for mechanical sealing applications. These piping arrangements are described in a series of plans issued by the API. Although 17 plans are described, only a few are really needed. Any time you have 17 choices there is bound to be some confusion. In the following paragraphs I will describe those API plans that I use on a regular basis, where I use these plans and, in the process, hopefully simplify your selection decisions.

Threaded fasteners set and hold tolerances on assemblies ranging from light-duty equipment to heavy machinery. Loosening is one of the major causes of industrial equipment failure, and results in millions of dollars worth of unscheduled downtime costs each year. In many cases, fasteners that self-loosen during equipment operation may contribute to wear and fatigue, and result in poor operating tolerances, misalignment and even catastrophic equipment failure. Various types of differential stresses such as vibration and shock, thermal expansion and contraction, and micro-movement reduce clamping force on the assembly and ultimately cause failure.

Maybe you’re thinking to yourself that the waste and inefficiency caused by using worn spray nozzles just can’t be all that significant. If so, it’s time to change your thinking and determine if nozzle wear is a problem in your operations. Like many other processors, you may discover that you are wasting millions of gallons of water, thousands of gallons of chemicals and incurring many other unnecessary costs due to using worn nozzles.

It is extremely important for any modern process company to have a good set of seal specifications. When written properly the seal specifications will classify seals by operation condition.

Open impellers are frequently used in centrifugal pumps which pump liquids that contain suspended solid materials (slurries, paper stock, etc). They do not plug as easily as closed impellers and usually have a simple external adjustment to maintain the correct impeller clearance as internal parts wear.

In theory, machine alignment is a straightforward process, but in real world applications, it is often compounded by structural faults such as ‘soft foot’, piping strain, induced frame distortion, excessive bearing clearance or shaft rubs. These pitfalls can turn a simple job into an all day affair – frequently with unsatisfactory results despite a conscientious effort and a considerable investment in manpower and downtime. This paper will examine how to eliminate some of the typical reasons why alignments are unsuccessful.