J4011 – PNEUMATIC & HYDRAULIC (hydraulic basic)

JJ512 – Pneumatic and

Hydraulic

Prepared by Hanizam bin Ibrahim

LEARNING OUTCOME

The student will be able to:State ISO standard symbols of hydraulic

components.Sketch the construction and describe the

application of gear, vane, piston and screw pump.

Describes a method to moving the valve.Sketch and describes the application of control

valves.Sketch and stated the purpose of hydraulic

actuators.

INTRODUCTION The hydraulic system is widely used in the

construction of heavy machinery such as bulldozers, tractors, drill machines, trucks and others.

Hydraulic system is better and efficient than Pneumatic systems in the construction of heavy machinery and use fluid as the medium.

Working principal of hydraulic systemThe pump is used to suck hydraulic fluid that

has driven by an electric motor to produces the flow of fluid.

Direction and flow rate of fluid is controlled by valves.Actuators are used to convert fluid pressure into mechanical movement (Power).

Standard symbols of hydraulic componentsNo Component Symbol

1 Fixed displacement hydraulic pump

2 Variable displacement hydraulic pump

3 Fixed displacement hydraulic motor

4 Variable displacement hydraulic motor

5 Fixed displacement hydraulic pump motor

6 Pneumatic motor

7 Variable displacement hydraulic pump

Standard symbols of hydraulic components (continue..)No Component Symbol

8Oscillating hydraulic actuators

9Oscillating pneumatic actuators

10Single acting cylinder without springs

11

Single acting cylinder with springs return

12Ram cylinder

13Double acting cylinder with single rod

14Double rod cylinders

15Cylinder with a single type of cushion

16 Cylinder with twin-cushion type


17 Single acting telescopic cylinder

18 Pressure relief valve

19 Flow control valve

20 Adjustable flow control valve

21 2/2 directional control valve

22 4/3 directional control valve with mid position close


24 3/3 directional control valve with single solenoid and spring return


26 Check valve


27 Shuttle valve

28 Adjustable flow control valve and check valve

29 Pressure switch

30 Filter

31 Diaphragm-type cylinder

32 Direct pilot

33 Indirect pilot

34 Spring

35 Adjustable spring

Hydraulic circuit

Cylinder

Directional Control Valve

Relief valve

Motor

Tank

Filter

Pump

Accumulator

Function of hydraulic components1. Tank (Basic)

Hold the hydraulic fluid. Act as a cooling system. Filter the dirt and contaminant in the system.

2. Filter (Accessory) filter the dirt in the hydraulic fluid before entering

the suction of pump.

3. Pump (Basic) Distribute the hydraulic fluid to the entire system.

4. Motor (Basic) Produce the power to drive the pump change the electrical energy to mechanical energy.

M

Function of hydraulic components5) Accumulator (Accessory)

Keep/ store the system pressure. Absorbing the vibration. stabilize the system pressure.

6) Valve (Basic) To regulate pressure in the circuit. To control the direction of

hydraulic To control the flow rate of the

hydraulic fluid.

Function of hydraulic components7) Pressure relief valve (Accessory)

To limit the maximum pressure of hydraulic fluid.

To prevent pump from damage cause by over pressure.

8) Cylinder (Basic) To produce the power to work for

linear motion.

Hydraulic Pump

IntroductionAll pump and motor used in hydrostatic is

a positive displacement type where leakage is minimal and can be ignored.

Pumps and motors can be divided into two main types1. Fixed displacement 2. Variable displacement.

Introduction Pumps can be divided into several types

as follows: -

PUMP

GearRam / Vane / Blade

Piston Screw

Gear pumpUsing two or more pairs of gears and it is

installed in a steel box with input (inlet) and output (outlet) channels.

The two gears in a pair are the same size.The compression occur between the gear and

housing wall. The rotation of gear will be increase the value of pressure and temperature.

Construction of gear pump

Inlet Outlet

Driven

Driver

Housing

Ram / vane / blade pumpConsisting of pairs of rotors with some free

sliding vane rotor with radial slit.Liquid will flow into the inlet when the space

between the casing and the rotor vane rotor becomes large and the liquid is removed from the room next door when space becomes smaller as the rotor rotates.

Construction of vane compressor

Inlet

Slotted rotorVane

Direction of rotation

Outlet

Screw pumpIt is durable because of the fluid used to act

as a safeguard against leakage. It can be used if the load applied to it does

not change. This type of pump requires oil filters mounted

in series at the outlet.

Construction of screw pump

Rotation

Outlet Inlet

Piston pumpPiston pumps are mostly used on systems with

operating pressures above or equal to 140 bar. The main feature of the piston pump is high

efficiency at high pressure. This is very important when a constant flow

without pressure changes. There are two types of multi-piston hydraulic

pump: 1. Axial type.2. Radial type.

Construction of piston pump

Bent Axis

Axial Plate Shaking

Types of Axial Piston pump

Construction of piston pump

Types of Radial Piston pump

Valve

Method of Moving a ValveThere are three (3) method of moving a valve:

1. Mechanical – roller and manual2. Pneumatic – pilot3. Electrical – solenoid

Method of Moving a Valve

Service Unit (FRL)

Air filterPressure regulatorLubricator

LubricatorPressure regulator

Air filter

Types of control valveThere are three (3) types of control valve:

1. Pressure control valve 2. Directional control valve3. Flow control valve4. is used to limit or control the system

pressure. It reduces the burden of a pump pressure or the temperature of the oil before the oil flow to the hydraulic circuit. Kawalann valve pressure can be divided into five types, namely: - relief valve and check

Pressure control valve To limit or control the system pressure. Reduces the burden of a pump pressure or

the temperature of the fluid before the fluid flow to the hydraulic circuit.

Can be divided into five types, namely: -1. Pressure relief valve2. Pressure reducing valve3. Pressure sequencing valve4. Pressure unloading valve5. Counter balance valve

Pressure control valve

1. Pressure relief valve 4. Pressure reducing valve

2. Pressure sequencing valve 5. Pressure unloading valve

3. Counter balance valve

Directional control valve Directional control valve is used as a path or

piloting the hydraulic fluid in the system. It has various types such as:

1. Rotor valve

2. Spool valve3. Open center and closed center valve4. Combination / multi spool valve

1. Rotor valve It is commonly used as a pilot valve to continue the

flow to other valves. Rotary-type directional control valve using a valve

rotors with 4-way oil output and input. These rotors have holes that can be connected to

the hole in the valve body when the rotor is rotated. This rotor is driven by a lever (lever) on hydraulic or

electrically.

2. Spool valve It was used to start or stop the direction of fluid in

the system. These valves could be control by manual, electrical

or hydraulic pilot and acting on the end of the spool. Tool setter is always used to determine the position of the valve in each operation.

Neutral position

Open center system - the pump will move continuously even directional control valve is in the neutral position. Hydraulic fluid will continue to flow from the pump through the control valve then return back into the tank.

Closed center system - the pump will stop when the control valve is in neutral. Directional control valve will stop the flow of fluid from the pump and cause the pump to stop running. Pump will be switched off by disconnecting the supply current to turn the motor pump. The switch is controlled by fluid pressure.

3. Open center and closed center valve

4. Combination / multi spool valve Two or more spool valve can be used in a group of

multi-function valve for operation. Construction of the spool valve depends on the

number of grafts in the operating valve.

Flow control valve Flow control valve can be adjusted in the

following manner: Limiting flow in or out of the component

which speed is easily adjusted. This type of valve is no compensation.

Change the flow direction to or from the component which speed is easily adjusted. This type of valve is usually compensated.

Can be divide into two (2) types:1. non-compensated valves2. compensated valves

1. Non-compensated valves Non-compensated valves will not be affected on the

pressure change. Commonly used when precise/accurate flow control is not

required. Examples of this valve is

1. Needle valve It was a simple limiter. When the needles were turned down, the flow will stop. When the needles moved up to open the screw, the orifice hole will open slightly and allow flow through it. When the screw is fully extended, the full flow can be created.

2. Globe valve.This valve is not sensitive to pressure changes. It is very simple and can be adjusted to obtain the desired flow rate.

1. Compensated valves Compensated valve will try to maintain the flow

rate even flow into the valve changed. Examples of this valve is

1. Compensated flow-control valveThis type of valve operates on the idea that the existing orifice size on components controlling the pressure drop at the orifice, causing the flow rate to be fixed. Orifice hole size at the end is connected to the spring. If the flow through the orifice is increases, pressure will also increase. The addition of flow will cause the spool moves to the right and hit the spring.

2. Bypass Flow regulatorCommonly used in open center system. By using this type of valve oil removed by pumps will be used to perform work on the main function.

Actuator

The construction and function is same as pneumatic actuator except the medium is hydraulic fluid.

The actuator change the hydraulic power to mechanical power.

Can de divided into two types:1. Cylinder for linear motion2. Motor for rotation

Introduction

Cylinder1. Single acting cylinder2. Double acting cylinder

Motor3. Screw4. Piston

a. Axialb. Radial

5. Vane/ram/blade6. Gear

a. External Gear b. Internal gear

** All construction and application of motor is same as pump except gear motor.

Gear MotorWidely used because it is

easy and economical. Normally it is used to move

a small component. Motor gear rotates in

clockwise or vice versa. It has a permanent shift. There are two (2) types

gear motor 1. external gear motor 2. internal motor gear.

Documents

J4011 – PNEUMATIC & HYDRAULIC (hydraulic basic)