I was asked recently to investigate and solve an overheating problem in a mobile hydraulics application. The hydraulic system that was overheating comprised a diesel-hydraulic power unit, which was being used to power a pipe-cutting saw. The saw was designed for sub-sea use and was connected to the hydraulic power unit on the surface via a 710-foot umbilical. The operating requirements for the saw were 24 gpm at 3000 psi. Heating of hydraulic fluid in operation is caused by inefficiencies. Inefficiencies result in losses of input power, which are converted to heat. A hydraulic system’s heat load is equal to the total power lost (PL) through inefficiencies.

Consumers use the term “flushing” to describe six different methods of bringing fluid to the stuffing box area of a centrifugal pump. Experienced seal people use different terms to differentiate between the methods. Water is one of the best barrier or buffer fluids because of its high specific heat and good conductivity. Petroleum oil is probably one of the worse because of its low specific heat and poor conductivity. Keep this in mind when you select a barrier or buffer fluid for your seals.

How long should a vertical pump’s suction bell last? That was a question a plant manager asked me during a recent consulting assignment for a power plant. A pump manufacturer’s typical response to such a question is, “it depends.” So what does it depend on?

In the pump business alignment means that the centerline of the pump is aligned with the centerline of the driver. Although this alignment was always a consideration with packed pumps, it is critical with sealed pumps especially if you are using rotating seal designs where the springs or bellows rotates with the shaft. A little misalignment at the power end of the pump is a lot of misalignment at the wet end, and unfortunately that is where the seal is located in most pump applications.

Pneumatic directional control valves and cylinders are most commonly used in power circuits, with the valves controlling cylinders that, in turn, provide work. As we learn about a few of these circuits, other accessory valves will be introduced, along with some interesting ways of using them.

Pump cavitation is defined as the phenomenon of formation and consequent implosion of vapor bubbles in a region where the pressure of the liquid falls below its vapor pressure. Cavitation can occur in any fluid handling equipment, especially in pumps, one of the most important components of industry today. Technological advances in industrial protective coatings and repair composite materials have made it possible to repair pumps suffering from cavitation rather than simply replacing them.

First of all, despite the fact that the PLC was designed as a direct replacement for relays, its logic is actually quite different. Relays are 100% parallel logic. Every single part of a relay control system operates simultaneously. If you were to draw several rungs on a relay diagram and put one coil on each line with no contacts on any of the lines, every relay would energize at the same time when power was applied. This makes relay logic blindingly fast by nature (its only the relay’s mechanical limitations that make it slow) but it’s often a source of trouble

There are 3 major problems associated with poor pump piping. 1) There is a scarcity of accessible information available on the topic. 2) No one pays any attention to it when installing a pump. 3) It can remain undetected and cause repetitive pump failures for many years.

The development of the electric motor has given us the most efficient and effective means to do work known to man. The electric motor is a simple device in principle. It converts electric energy into mechanical energy. Over the years, electric motors have changed substantially in design, however the basic principles have remained the same. In this section of the Action Guide we will discuss these basic motor principles. We will discuss the phenomena of magnetism, AC current and basic motor operation.