Types of Accumulator | Weight, Spring, Gas Loaded Accumulator

Types of accumulator

Weight loaded accumulator

It consists of a piston which is loaded with a dead weight and moving within a cylinder this tends to exert pressure on the hydraulic fluid. Potential energy to compress the fluid is generated by the dead weight present on the piston. Concrete block, iron or steel is generally used as dead weight. The piston is made to move in the accumulator in precision fit in order to reduce the leakage. One side of the accumulator is connected to the fluid source and other to the machine.

01 - weight loaded accumulator - type of accumulator

Working

The ram is at the lower most position at the beginning of a cycle. The fluid is admitted continuously inside the cylinder during the idling period where the drive is provided by the machine. This makes the ram to reach the top most position, thus the piston or the plunger gains its potential energy. During the working stroke the accumulator is discharged to drive the machine.

Spring loaded accumulator

This type of accumulators is similar to that of the dead weight loaded type of accumulator. Spring loaded consists of spring in place of the dead.it is preloaded with the help of compression spring. It consists of a cylindrical body, a movable plunger and a compression spring.

01 - spring loaded accumulator - types of accumulator

Working

In the beginning the spring is in a compressed stage which makes the hydraulic fluid to flow inside the cylinder of the accumulator. Load of the spring is responsible for the pressure inside the cylinder.as the spring gets compressed the pressure inside the accumulator gets increased. When the fluid gets discharged out of the cylinder the spring gets expanded.in this method also the pressure exerted on the fluid is not constant as that of weight loaded type

Gas loaded type accumulator

This type of accumulator is also called as hydro pneumatic accumulator. This accumulator is widely used in many types of industries. This is classified into two types. They are,

Non-separator type accumulator

It consists of fully enclosed shell containing pneumatic-loaded actuator, gas charging port in the op and oil port at the bottom. The gas is occupied on the top and the hydraulic fluid is present at the bottom since there is no membrane to separate the gas and the hydraulic fluid it is called as non-separator type accumulator.

01 - non seperator type accumulator - gas loaded accumulator

Working

In this type of accumulator pressurization is achieved by the entry of pressurized gas into the cylinder. When the pressure of the machine increases the oil port opens and the oil enters the cylinder and the volume of the gas is reduced. This reduction in volume of the gas increases the pressure. This pressure gap or potential energy is used to drive the accumulator.

Separator type accumulator

the construction of the outer parts are similar to that of the non-separator type except that it consists of an additional piston separator or seal.

01 - seperator type accumulator - gas loaded accumulator

Working

The piston serves as the barrier between the gas and the hydraulic fluid. The working is similar to that of the non-separator type of accumulator. The gas gets compressed when the charged oil pushes the piston against it. The reduction in volume of the gas increases the pressure. This pressure gap or potential energy is used to force the oil out of cylinder when it is required in the circuit.

Taper Turning Methods in Lathe Machine | Types of Taper Turning

Taper turning methods in lathe machine

There are four methods

1. Form tool method

2. Tailstock set over method

3. Compound rest method

4. Taper turning attachment method

Form tool method

This is one of the simplest methods to produce short taper. This method is shown in the above figure. To the required angle the form is grounded. The tool is fed perpendicular to the lathe axis, when the work piece rotates.

01 - taper turning by form tool method - taper turning

The tool cutting edge length must be greater than the taper length. Since the entire cutting edge removes the metal, it will produce a lot of vibration and hence a large force is required. It is done in slow speed.

Tailstock set over method

Generally, when the angle of taper is very small this method will be employed. The work piece be placed in the live center and live center. Now, the tailstock will be moved in a cross wise, that is perpendicular to the lathe axis by turning the set over method. This process is known as tail stock set over method.

01 - tail stock set over method - taper turning method

Hence here the job is inclined to the required angle. When the work piece rotates the tool is moved parallel to the lathe axis. So that the taper will be generated on the work piece.

Compound rest method

Generally short and steep taper will be produced will be produced using this method. In this method the work piece will be held in the chuck and it will be rotated about the lathe axis. The compound rest is swiveled to the required angle and then it will be clamped in position.

01 - compound rest method - taper turning method

The angle is determined using the formula, tan

Then by using the compound rest hand wheel the tool will be fed. Both the internal and external taper can be done using this method. The important feature is that the compound rest can be swiveled up to 45° on both sides. Only with the help of the hand the tool should be moved.

Taper turning attachment method

In this method by using bottom plate or bracket, a taper turning attachment is attached to the rear end of the bed. It has a guide bar which is usually pivoted as its center. The guide bar has the ability to swing and it can be set in any required angle. It has graduations in degrees. On either side, the guide bar can be sweivelled to a maximum angle of 10°. It has a guide block which connects to the rear end of the cross slide and it moves on the guide bar. The binder screw is removed, before connecting the cross slide, hence the cross slide is free from the cross slide screw.

01 - Taper turning attachment method - taper turning method

Usually during taper turning, the job will be held in the chucks or in the centers. To the required angle the guide bar turned.

The angle is calculated using the formula, tanα = (D-d)/2l

When the division is given in mm instead of degree, then the angular distance of the guide bar to be tilted is given by

Using the compound rest hand wheel the depth of cut will be given. At an half taper angle the guide will be set. Using this method any taper turning method can be done.