Hydraulic Devices

Operation of Hydraulic Machine

Simple hydraulic machine is shown in Fig 1 above.

The followings are shown as Parts of the Hydraulic machine

1. Pump .

i.   Can be Electrical pump with induction motor.

ii.  Can be Mechanical pump operated with diesel engine or gasoline engine

2.  Valve. .  

i.   can be Electrical valve with solenoid

ii.  Can be Mechanical that is operated manually.

1. Hose. This transmit the hydraulic oil to the cylinder
2. The cylinder. This moves IN or OUT when the valve is operated and exacted force on the load.
3. Hydraulic oil container. This serves as the storage for the hydraulic oil.

Operation

When the pump is switch on through its prime mover(induction motor or diesel engine). The hydraulic oil is pumped out from the hydraulic oil container to the Valve. The return pipe is normally open and the oil returns back to the hydraulic container.

While the pump is still ON , the valve is controlled to close the return pipe and open the cylinder OUT hose , then the hydraulic oil moves to the cylinder OUT hose and this force the cylinder to move out and exert force on the load.

The valve is also controlled in the same way while the return pipe is still closed. The cylinder OUT hose is closed from the  valve and cylinder IN hose is opened from the valve. This forced the cylinder to move IN with a force and withdraw from the load.

Many Hydraulic valves can be connected to the same hydraulic oil container to control different cylinders.

Simple hydraulic machine is seen in HIAB which is operated with a diesel engine and mechanical valve.

Some hydraulic press are operated with hydraulic machine rather than the use of pressure transmission f/a=F/A explained earlier .

Car Brake Hydraulic device

In the figure 2 above, when the pedal is pressed the hydraulic oil in the brake pipe force the brake pad to exact a force on the brake shoe thereby hook the tyre and force the car to stop.

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