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.

What is electrical corona? Corona is the ionization of the nitrogen in the air, caused by an intense electrical field. Electrical corona can be distinguished from arcing in that corona starts and stops at essentially the same voltage and is invisible during the day and requires darkness to see at night. Arcing starts at a voltage and stops at a voltage about 50% lower and is visible to the naked eye day or night if the gap is large enough (about 5/8″ at 3500 volts).

Regardless of the approach taken to measure true dynamic movement, coupled machines need to be set to cold alignment targets that will reflect the actual changes in the shaft alignment. This will lead to lower vibration levels, increased Mean Time Between Failures, decreased maintenance expenditures and increases in production. Much like the philosophical change from aligning shafts with dial indicators to aligning shafts with laser based systems, these types of measurements will take some time to be generally accepted and routinely practiced.

Mass unbalance in a rotating system often produces excessive synchronous forces that reduce the life span of various mechanical elements. Unbalance is basically very simple case caused by an asymmetry in the rotating element that results in an offset between the shaft centerline and center of mass. Asymmetry can be an off-center weight distribution, or it can be a thermal mechanism that produces uneven heating and bowing of the rotor, or it can be an electrical effect that produces uneven magnetic field.

Machinery can be idle from intermittent use, stand-by (redundancy), storage for spare parts, or for temporary decommissioning. This article looks at practices that protect equipment characterized as decommissioned, short-term storage or storage of stand-by capacity.