August 26, 2011


Mechanical seal is the best answer by a pair or several pairs of perpendicular to the axis of relative sliding of the end for the fluid pressure and the compensation mechanism in the elastic (or magnetic) to keep under seal affixed to merge to achieve together with auxiliary shaft seal leakage resistance device.

Mechanical seal structure used by the geostationary ring (stationary ring) 1, rotating ring (ring) 2, the elastic element 3, the spring seat 4, 5, set screws, rotating ring supporting ring 6 and the stationary ring composed of auxiliary components such as seals 8 , 7 fixed to the gland against resellers to prevent the stationary ring 9 on the turn. Rotating ring and stationary ring often can be compensated according to whether they have the ability to axial or non-compensation is also known as the compensation ring.

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August 26, 2011


Mechanical seals are used to prevent leakage from rotating equipment such as pumps or compressors. There is always a risk of a liquid, such as oil, leaking out of a pump and contaminating the environment. Seals reduce the probability of leaking by wrapping around a pump and providing a tight enclosure. There are several types of seals available to protect mechanical pumps.

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August 26, 2011

Pumps aboard ship outnumber all other auxiliary machinery units. They include such types as centrifugal, rotary, and jet pumps. In the following section we discuss these different pumps and their application to the engineering plant.

Centrifugal Pumps

Aboard gas turbine ships, centrifugal pumps of various sizes are driven by electric motors to move different types of liquid. The fire pump and seawater service pump are two examples of this type of pump.

A basic centrifugal pump has an impeller keyed to a drive shaft, which is rotated by an electric motor. The drive shaft is fitted inside a casing, which has a suction inlet and a discharge

Figure 9-1.-Centrifugal pump.

outlet. Figure 9-1 shows the arrangement of components in a centrifugal pump.

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Maintenance and Troubleshooting of Electric Motors

August 22, 2011


The key to minimizing motor problems is scheduled routine inspection and service. The frequency of routine service varies widely between applications.

Including the motors in the maintenance schedule for the driven machine or general plant equipment is usually sufficient. A motor may require additional or more frequent attention if a breakdown would cause health or safety problems, severe loss of production, damage to expensive equipment or other serious losses.

Written records indicating date, items inspected, service performed and motor condition are important to an effective routine maintenance program. From such records, specific problems in each application can be identified and solved routinely to avoid breakdowns and production losses.

The routine inspection and servicing can generally be done without disconnecting or disassembling the motor. It involves the following factors:

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What is Human Machine Interface?

July 26, 2011

A human machine interface (HMI) is an interface which permits interaction between a human being and a machine. Human machine interfaces vary widely, from control panels for nuclear power plants to the screen and input buttons on a cell phone. Designing such interfaces is a challenge, and requires a great deal of work to make the interface functional, accessible, pleasant to use, and logical. Some engineers specialize in developing human machine interfaces and changing the ways in which people interact with machines and systems.

Two components are needed in a human machine interface. The first is an input. A human user needs some way to tell the machine what to do, to make requests of the machine, or to adjust the machine. Examples of input devices include keyboards, toggles, switches, touch screens, joysticks, and mice. All of these devices can be utilized to send commands to a system or even an interlinked set of systems.

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