Anna University Exam Papers – Mechanical Engineering – Hydraulic & Pneumatic Controls – VI Semester









TIME – 3 Hours                                                                    MAXIMUM : 100 Marks


PART – A                     (10 x 2 = 20 Marks)

  1. What do you mean by cushioning of Fluid power actuators?.
  2. A double acting cylinder is hooked up in the regenerative circuit.

The relief valve setting is 68.94 bar and the Piston area

is 6.35 x 10-3m2 & the rod area is 1.778 x 10-3 m2. If the pump

flow is 75.706 lpm find the cylinder speed for retracting stroke

  1. List out the four types of fire resistant hydraulic fluids?
  2. What is F-R-L and what is the function of a lubricator?
  3. State the functions of accumulator in hydraulic Circuits?
  4. Draw the symbol for a relief value and pressure reducing value.

7.  List out the basic types of filtering methods used in hydraulic systems.

8.   List out the most widely used types of seal configurations.

9.   What is a Pneumatic Vacuum System?

10.  What is the use of ladder diagram?

PART B                             (5 x 16 = 80 Marks)

11(a) (i) .For the Hydraulic system shown below, the following data are given

The pump is adding 3.68 kW of power to the fluid.

Pump flow is 0.001896m3/sec

The pipe has a 0.0254m inside diameter.

The specific gravity of oil is 0.9

The kinematic viscosity of oil is 100mm2/sec

The elevation difference between stations 1 and 2 is 6.096m

Pipe lengths are as follows:0. 305m, 1.22m, 4.88m.

Find the pressure available at the inlet to the Hydraulic motor

(Station2). The tank top surface of the hydraulic tank is exposed

to atmosphere. The head loss due to friction between station1

and 2 is not known?                                                                      (8 Marks)

(ii) Explain with neat diagrams closed loop (servo) electro hydraulic

control system and open loop hydraulic system                       (8 Marks)

12. (a) (i) Explain the working of an unbalanced fixed displacement

vane pump with a neat sketch.                                               (8 Marks)

(ii) Explain the working of an axial piston pump of bent – axis

type with neat sketch.                                                               (8 Marks)

( OR )

 (b) (i). Draw and explain constructional features of a 5/3-direction

            control valve of linear type along with its graphical symbol.    (8 Marks)

(ii). With neat sketch explain the operations of a pressure-

      reducing valve. Sketch its graphical symbol                            (8 Marks)

  1. (a) With the help of circuits, explain how synchronizing of two

linear actuators are achieved by connecting them in series

and in parallel                                                                                 (16 Marks)

( OR )

      (b) (i). Construct a hydraulic circuit to explain the application of regenerative system in a drilling machine.                         (8 Marks)

(ii) Construct a double pump hydraulic circuit employed

in a punching press and explain how it functions.              (8 Marks)

14) a.(i) Design a fluidic box sorting system for two different sized

boxes moving on a conveyor by making use of the

preferenced  flip flop ,DCV and Push buttons.                        (8 Marks)

(ii) Design a fluidic sequencing control of two pneumatic cylinders

using flip-flop, OR Gate, Push buttons, Directional control valves

etc for the following sequence;

Cylinder 1 extends

Cylinder 2 extends

Both cylinders retract together.                                           (8 Marks)

( OR )

.        (b) (i) Briefly explain the various electrical devices used in the

control of Fluid Power systems.                                                (9 Marks)

(iI) Design and explain Electro pneumatic circuit for automobile reciprocation of a Double acting cylinder using pressure

switches.                                                                                          (9 Marks)

15 (a).(i) What is PLC? Explain the elements of PLC with

block diagram.                                                                             (12 Marks)

(ii). Write down the advantage of PLC over electro mechanical

relays system.                                                                       (4 Marks)

( OR )

       (b). Design and explain a sequential circuit using cascade method

for the following sequence.                                                    (16 Marks)

A + B + A  B

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