When printing an image that has more than one color, it is necessary to print each color separately and ensure each color overlaps the others precisely. If this is not done, the finished image will look fuzzy, blurred or "out of register" (see image to bottom). To help line the colors up correctly, a system of registration is necessary.
The four dots blue (cyan), pink (magenta), yellow and black are registration marks used during printing to help ensure the print is aligned properly. In offset printing technology, which newspapers use, the inked image is transferred from a plate to a rubber blanket, then to the printing surface. These primary colours go into printing a multi-coloured image and have separate plates. Each plate has its individual mark, like the colour dot.
External gear pumps are a popular pumping principle and are often used as lubrication pumps in machine tools, in fluid power transfer units, and as oil pumps in engines.Gear pumps are also widely used in chemical installations to pump high viscosity fluids.
Working of gear pump :-
External gear pumps are similar in pumping action to internal gear pumps in that two gears come into and out of mesh to produce flow. However, the external gear pump uses two identical gears rotating against each other -- one gear is driven by a motor and it in turn drives the other gear. Each gear is supported by a shaft with bearings on both sides of the gear.
1. As the gears come out of mesh, they create expanding volume on the inlet side of the pump. Liquid flows into the cavity and is trapped by the gear teeth as they rotate.
2. Liquid travels around the interior of the casing in the pockets between the teeth and the casing -- it does not pass between the gears.
3. Finally, the meshing of the gears forces liquid through the outlet port under pressure.Because the gears are supported on both sides, external gear pumps are quiet-running and are routinely used for high-pressure applications such as hydraulic applications. With no overhung bearing loads, the rotor shaft can't deflect and cause premature wear.
Advantages :-
- High speed
- High pressure
- No overhung bearing loads
- Relatively quiet operation
- Design accommodates wide variety of materials
Disadvantages :-
- Four bushings in liquid area
- No solids allowed
- Fixed End Clearances
Applications :-
Common external gear pump applications include, but are not limited to:
- Various fuel oils and lube oils
- Chemical additive and polymer metering
- Chemical mixing and blending (double pump)
- Industrial and mobile hydraulic applications (log splitters, lifts, etc.)
- Acids and caustic (stainless steel or composite construction)
- Low volume transfer or application
The device we see at the rear of a car is known as spoiler.It is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across a body of a vehicle in motion, usually described as turbulence or drag.
When car is running at high speed, two basic aerodynamic forces act on the car,first one is lift and second one is drag.The lift force tends to lift the car from the ground as a result the grip is reduced and vehicle becomes unstable.
A spoiler is fundamentally an inverted aircraft wing. The wings of a aircraft generates lift which helps the aircraft take off. While the spoilers also generate lift, because they are inverted, they push the car down on the ground.Thus,it increases the car’s grip on the road.
Without spoilers, the only way to increase the grip would be to increase the weight, or to change the compound the tire was made out of. The only problem with increasing the weight is that it doesn't help in turns, where you really want to grip. All that extra weight has inertia, which you have to overcome to turn, so increasing the weight doesn't help at all.Also,increased weight will result in increased fuel consumption.
Spoilers on commercial vehicles are generally added for styling purposes and have either little or no aerodynamic benefit.
