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Glossary of terms you will come across during your Phase 2 training.


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U

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A U-tube operates by the following principle:

Diagram illustrating the u-tube principleIf you have liquid in a u-tube, and both sides of the tube are exposed to the same pressure, the level of liquid in one side of the tube will always be exactly the same as the level of liquid in the far side.

If I want to alter the levels of liquid in either side, I can raise or lower the pressure on one side only to achieve the desired effect.

For example, in the Small Plant Module, Petrol and LPG Learning Unit, we look at float chamber carburettors.

In this device, the float chamber, main jet and main jet orifice form a u-tube.

In this arrangement, we allow atmospheric pressure to act on the surface of the fuel in the float chamber.

When the engine is not running, atmospheric pressure also acts on the main jet orifice.

Because there is equal pressure on both sides of this arrangement, no fuel will flow from the float chamber and out of the main jet orifice.

Float chamber carburettorHowever, once we run the engine, air being induced into the engine on the induction stroke is forced to speed up in order to get through the venturii of the carburettor.

This increase in air speed produces a corresponding drop in air pressure around the main jet orifice.

Now we have a situation where we have atmospheric pressure acting on the fuel in the float chamber (one side of the u-tube), and less than atmospheric pressure acting on the main jet orifice (the other side of the u-tube).

This imbalance of pressures causes fuel to flow from the float chamber, through the main jet and out the main jet orifice, where the air stream will carry it into the combustion chamber for burning. 

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Harness repair kit, supplied by Perkins:

Harness repair kit supplied by Perkins

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This is the Perkins part number of a fuel line blanking kit. The kit consists of four different size blanks, designed for use with the 1104 and 1106 common rail engines.

Fuel line blanking kit

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Company contact for Unilokomotive Ltd.

Telephone: 093 52150

Apprentices:

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Ultraviolet (UV) is electromagnetic radiation with wavelength shorter than that of visible light but longer than X-rays.

UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights.

Although long-wavelength can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules.

Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact.

For humans, suntan and sunburn are familiar effects of exposure of the skin to UV light, along with an increased risk of skin cancer.

The amount of UV light produced by the Sun means that the Earth would not be able to sustain life on dry land if most of that light were not filtered out by the atmosphere.

Ultraviolet light is also responsible for the formation of bone-strengthening vitamin D in humans.

The UV spectrum thus has effects both beneficial and harmful to life.

The lower wavelength limit of human vision is conventionally taken as 400 nm, so ultraviolet rays are invisible to humans, although some people can perceive light at slightly shorter wavelengths than this. Insects, birds, and some mammals can see near-UV (i.e. slightly shorter wavelengths than humans can see).

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The only authorised absence from Phase 2 training is certified sick leave. Certified sick leave is where you furnish a sick note from a medical doctor.

Your instructor also has limited discretion to authorise short absences on compassionate grounds, such as the death of a family member.

All other absence is unauthorised and will attract a formal verbal warning (DR1) for the first absence, and a written warning and suspension from the course (DR2) for a second absence.

Further absence will attract a DR3 can result in the termination of your Phase 2 training and your apprenticeship.

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From their website:

Unilokomotive Limited manufactures the Unilok road / rail wagon mover or shunting locomotive used for moving railway wagons, carriages or locomotives. Uniloks are not truck conversions, but purpose built rail yard workhorses that travel as easily on road as on rail. Uniloks carry out shunting tasks that locomotives 4 to 5 times there weight would do, but with greater mobility and at a fraction of the cost. Read More...

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Unit injectorThis refers to a fuel injector in a diesel engine that is constantly connected to a high pressure fuel rail (common rail). When the ECM (the engine computer) wants the injector to fire, it sends a signal to an electrical solenoid in the injector, which lifts the needle. Because the fuel inside is under massive pressure, injection occurs at this instant.

CAUTION: This unit is connected to a very high pressure supply, in the region of 1,600 bar (approx. 23,000 psi). Always wait until the engine has been switched off for one minute before attempting to disconnect the fuel supply pipe.

Never re-use an injector pipe, always fit a new one.

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In the context of fuel, specifically petrol, lead (or more precisely, tetraethyl lead) used to be added to fuel, where it acted as an anti-knock inhibitor. It was very good in this role, but the problem was that 75% of it was passed out the exhaust and into the environment.
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Uniform resource locator. This is the unique address of a web site on the Internet.

For example, the URL, or Uniform Resource Locator, or web address of the CP Fitters' Homepage is: www.fascabra.com/cpweb/index.htm


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