Maintenance Equipment: Basic of Centrifugal Pumps

Cooling systems are vital and integral components at thousands of industrial plants.  Properly designed and operated chemical treatment systems, preventive maintenance of such, and monitoring are absolutely critical to minimize failures that otherwise may cause partial or full plant outages.  In the next three parts of this series, we will examine the water-side issues of microbiological fouling, scale formation, and corrosion that require attention during both the design and operation of open-recirculating cooling systems like those discussed in Part 1 of this series. 

Sizing electric motors correctly for hydraulic power units can save a sizable amount of money over the life of the equipment. If system pressure and flow are constant, motor sizing simply boils down to the standard equation: hp = QP / 1714EM

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.

The affinity laws accurately predict the affect of changing the speed of a centrifugal or rotary pump, and they also do a fairly good job of predicting the affect of changing the diameter of a centrifugal pump. In another paper (02-01) we discussed the affinity laws as they apply to centrifugal pumps, but in this paper we will look at their use with rotary pumps.

In Part 1 of this series, we will examine some of the most important components of cooling towers, and from that will build upon issues that can affect cooling system performance and operation. One of the later installments will address closed cooling water systems.

Is your scrubbing tower working? A wet scrubbing tower is used to clean odors, particles, mists, and vapors from a gas stream. The gas is forced through the tower. As it moves from inlet to outlet it is washed and cleaned. The washing is done with suitable chemicals that remove the active components in the gas flow. The gas is cleaned to environmentally acceptable levels and discharged to atmosphere.

Part one of a four-part series that will cover alignment fundamentals and thermal growth, and highlight the importance of field measurements through two case studies. Despite the best efforts to precisely align rotating machinery shafts, dynamic movement (commonly believed to be due to the thermal growth of the machine casings) has resulted in machines operating at less than optimum alignment conditions. This vexing problem has plagued machine reliability professionals for decades.