Hydraulic Machines

Engr. Mahesh Kumar

Hydraulic Crane

• The hydraulic crane is used for transferring or raising heavy loads.

• It can be used up to loads 25 MN.• It is widely used in loading and unloading ship,

warehouses, workshop, heavy industries and dock sidings.

Construction

Parts of hydraulic crane

• Tie• Jib• Guide pulley• Jigger• Hollow vertical post

Construction

• The jib and tie are attached to the vertical post. Jib is hinged near the foot of the vertical post .

Construction

• Hydraulic jigger consist of a movable ram sliding in a fixed cylinder . The sliding ram, one end is connected to set of movable pulley block and other end is contact with water.

Construction • One end of wire rope

fixed with cylinder body is taken round all the pulley of the two sets of pulley and at the end passes round the guide pulley block.

• The free end of the wire rope is attached with a hook for suspending the load.

Working

During the lifting the load by crane, the high pressure water is admitted into the fixed cylinder of jigger.

Working

The pressuriesed water forces the sliding ram to move right with movable pulley bock.

So that the distance between two pulley blocks increases

Working

Which causes the wire passing over the guide pulley is pulled by the jigger and hence the load attached to hook is lifted.

For lower the load, close inlet valve and open wast valve so that water is forced out the cylinder hence ram moves towards the left and distance between two pulley blocks decreases, which release the wire rope and the load is lowering down

Application

• Hydraulic crane used for lowering workshop, foundary, loading and unloading of ship and Railway wagons and heavy industries.

Hydraulic Lift

• It is a device used to carry person and load from one

floor to another, in a multistory building

• There are two types

1) Direct acting Hydraulic Lift

2) Suspended Hydraulic Lift

Direct Acting Hydraulic Lift

• Consist of a ram sliding in a cylinder

• A platform or cage is fitted on top end of ram on which good or person can stand.

• The liquid in cylinder is admitted , which causes ram to move up

• The lift is equal to stroke of the ram

Suspended Hydraulic Lift • It is modified from direct acting

hydraulic lift

• It is fitted with jigger same case as hydraulic crane

• The cage is suspended by ropes.

• It runs between guides of hard wood or round steel

• The modern lift can achieve velocity of 100 to 120 m per minutes

• Hydraulic ram is a device by which small quantities of water can be pumped to higher levels from available large quantity of water to of low head

• It consist of a valve box wherein low head water flow

• The box contain waste valve V1 which opens inward, and

delivery valve V2, which opens outward.

• Both V1 and V2 are non return valve, that allow flow in

one direction

• Valve V2 communicates with air vessel which is connected

to delivery tank through delivery pipe

Hydraulic Ram

Hydraulic Ram

Working• It work on principle of water hammer• When water is brought to rest, the change in

momentum of liquid mass causes a sudden rise in pressure

• This rise in pressure is utilized to raise a portion of liquid to higher level

Hydraulic Ram• Initially water flows down the supply pipe, the

valve V1 is open and water escape through it to waste

Hydraulic Ram

Hydraulic Ram• As the velocity of flow in supply pipe increases, dynamic

pressure on under side of valve V1 becomes high so as

to lift the valve V1 and ultimately closes it

• Due to quick closer of valve V1 water in supply pipe is

suddenly brought to rest and consequently pressure in valve box increases

• The increase high pressure lift the valve V2 and a part of

water enter air vessel

Hydraulic Ram

Thank You…