87573670 hydraulic circuits

7/21/2019 87573670 Hydraulic Circuits

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HYDRAULIC CIRCUITS

BYP.T.GANGADHARAN

11MP64


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FLUID POWER:

Fluid power Technology is a mean to convert , transmit and control the

fluid energy to perform useful work.

Fluid may be either liquid or gas.

Hydraulic system - Pressurised liquid Pneumatic system - Compressed Air


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PASCALS LAW

Pressure generated at any point in a confined liquid acts equally in alldirections.


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ELEMENTS OF HYDRAULIC SYSTEMS


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PUMPS

It is a device which convert mechanical energy into hydraulic energy.

Principle:

To create partial vaccum at inlet which permits atmospherics pressure to

force the fluid through the inlet line and into the pump.

Types of Pump:

1. Hydrodynamic or Non Positive displacement pumps

2. Hydrostatic or Positive displacement pumps


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Hydrodynamic or Non Positive displacement pumps

Examples : Centrifugal and Propeller pumps

Normally it provides smooth continuous flow.

If resistance inside the circuit increases then flow will get reduce.

It is possible to completely block off the outlet to stop all flow even thepump is running at design speed. since there is great deal of clearancebetween the rotating and stationary elements.

Thus the flow rate is not only depends on rational speed but also onresistance on the external system.


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Hydrostatic or Positive displacement pumps

It always deliver a fixed quantity of fluid per revolution of pump shaft.

The pump outlet is constant and is not dependent on system pressure.

It must be protected against overpressure (extremely rapid build up ofpressure even though it has no place to go)

Classification:

1. Gear Pumps

a. External gear pumps

b. Internal gear pumps

c. Lobe pumps

d. Screw pumps

2. Vane Pumps

a. Unbalanced vane pumps

b. Balanced vane pumps

3.Piston Pumps

a. Axial Design

b. Radial Design


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Hydrostatic or Positive displacement pumps

Classification:

1. Gear Pumps

a. External gear pumps

b. Internal gear pumps

c. Lobe pumps

d. Screw pumps2. Vane Pumps

a. Unbalanced vane pumps

b. Balanced vane pumps

3.Piston Pumps

a. Axial Design

b. Radial Design


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PUMPS


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CONTROL VALVES

Pressure control valves (PCV)

To control the liquid pressure.


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CONTROL VALVES

Flow Control Valves (FCV)

To control the liquid flow rate.


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Direction Control Valve (DCV)

To control the direction of flow of liquid.

CONTROL VALVES


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ACTUATORS

It is used to sift the DCV into different positions.


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HYDRAULIC MOTOR

It is used where rotary motion is desire.


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HYDRAULIC CYLINDER

It is used where linear motion is desire.


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HYDRAULIC CIRCUITS

SYNCHRONISING CIRCUITS:

SERIES PIPING.

MATCHING PUMPS.

SYNCHRONISING WITH FLOW CONTROL VALVES

AUTOMATIC CYLINDER RECIPROCATING CIRCUIT.

SEQUENCE OPERATION BY USE OF CAM VALVE.

TWO HAND SAFTY CONTROL CIRCUIT.


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SERIES PIPING


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MATCHING PUMPS:


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SYNCHRONISING WITH FLOW CONTROL VALVES


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AUTOMATIC CYLINDER RECIPROCATING CIRCUIT


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SEQUENCE OPERATION BY USE OF USE OF CAM VALVE


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TWO HAND SAFTY CIRCUITTWO HAND SAFTY CONTROL CIRCUIT


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APPLICATIONS:

Construction: Earth-Moving Equipment, concrete Mixing

equipment

Ships : Controllable pitch propellers

Aviation : Hydraulic retractable landing wheels.

Defense : Missile launch system, navigation controls.

Transportation: Hydraulic presses for metal forming,

pneumatic hand tools, injection molding

machine etc.,

Material handling: Hydraulic jacks, hydraulic rams, conveyor

system etc.,

Automation :Hydraulic operated machine tools, Robots etc.,

87573670 hydraulic circuits

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