hydropneumatic circuits

HYDROPNEUMATIC CIRCUITS

HYDROPNEUMATIC (OR PNEUMOHYDRAULIC) CIRCUITS

1. What are Hydropneumatic Circuits?

• In some applications, the hydraulic and pneumatic circuits are coupled to get best use of the advantages of both oil and air mediums. This combination circuits are known as hydropneumatic or pneumohyraulic circuits.

• As we know, due to compressibility characteristics of air, the pneumatic actuators are not preferred for precision control of position and speed. At the same time, hydraulic systems are not so economical as well as lacks overall fastness when compared to pneumatic systems. The combination of hydraulics and pneumatics solves the above problems of precision control, fastness and economy.

• However, it should be kept in mind that though both fluids (oil and air) are used in the same circuit, they are not mixed together. In fact, every precaution should be taken to keep them separated.

2. Uses of Hydropneumatic Circuits

1. Using the combination of air-hydraulic unit, the quick action of air and smooth, high- pressure action of oil can be blended.

2. The combination circuit will reduce space requirements.

3. The combination circuit will reduce initial and maintenance cost of original equipment.

4. It will increase the performance of the equipment.

5. It will allow more flexibility.

6. The combination circuit such as an air-hydraulic cylinder is especially suitable in explosive atmospheres because of the absence of electrical equipment.

Now we shall discuss one such combination circuit.