Machine Alignment: Alignment Pitfalls – How to Identify and Eliminate Them

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.

Machine conditions change from the time the machine is off line to when it is running under normal operating conditions. Some of these changes are due to process forces (e.g., fluid pressures, airflow, etc.). The most notable of these changes is the change in the temperature of the machine bearings and supports. This is called the machine's thermal growth.

How do control valves work? Control valves regulate the flow of a liquid or gas by opening or closing internal passages. They form part of a control loop used to control a process. The control valves respond to instructions from the controller and adjusts the internal openings accordingly.

Rotary dryers, kilns, mills and reactors turn on tires and trunnions. Each tire is mounted to the rotating shell and revolves on two roller trunnions. If the alignment between the tire and trunnions is lost due to wear, poor repair, installation error or impact, the equipment will need to be tracked. 

Process pump reliability logically involves a combination of fluid-related performance and design decisions that focus on engineering materials and the configuration of mechanical components. Recent case studies have pointed out improvement opportunities in the relative design conservatism found in certain process pump models. Combined with deficiencies in the training of personnel, it can be argued that pump reliability has not made as much progress as it perhaps could.

Oh "Overall Equipment Effectiveness", I've heard about that before! Unfortunately, in many facilities, that's all OEE (Overall Equipment Effectiveness) is to the personnel. Something they heard of, talked about or read about. Many maintenance departments today still do not effectively utilize the OEE tool even though it's widely used among the world class companies.

The power industry’s operating and maintenance practices were held up to intense regulator and public scrutiny when on November 6, 2007, a Massachusetts power plant’s steam-generating boiler exploded and three men died. The Department of Public Safety’s Incident Report investigation determined that the primary cause of the Dominion Energy New England’s Salem Harbor Generating Station Unit 3 explosion was extensive corrosion of boiler tubes