7/25/2019 ME2305-AHP-5

1/3

ME 2305 - APPLIED HYDRAULICS AND PNEUMATICS

TWO MARK QUESTION AND ANSWER

UNIT V

1. What is Low Cost Automation?

There are five stages of manufacturing process for automation namely

1. Loading 2. Clamping 3. Machining 4. Unclamping 5. Unloading.

The cost involved in loading and unloading stages is very high. So, in semi automation, these two states aredone manually and other stages are automated. Semi automation can be profitably being incorporated inmanufacturing industries. This type of automation is called "Low Cost Automation"

Also, in many industries, automation is done in selected areas to enhance the productivity. Material

handling and machine sequence are examples of such type of automation.

2. What is meant by automation?

Automation of a process plant (or) a flow line is done by means of specially designed machinery andequipments, which represent the highest level of automation. Chemical processing and automated assembly linesare examples of such automation

3. What are the salient features of "Low cost Automation".

In most of the industrial plants, centralized compressed air supply will exist. Hence, simple automationof machining sequences (or) material handling can be done without much expense. Low cost automation isattempted without going for a major alteration of the existing set up. Low cost automation enhances productivity.

The sequencing pneumatic circuit is an example of "Low cost Automation"

4. Name two types of control systems?

o Open loop control system

o Closed loop control system.

7/25/2019 ME2305-AHP-5

2/3

5. Explain the closed loop control system for a flow through a pipe?

A flow through pipe is continuously measured and compared with the desired value to get the error signal(error signal is a difference between actual and desired values). Based on this error signal, the controller gives asignal to actuate the valve to adjust the flow (increase (or) decrease depending on the value of error being

positive (or) negative). This is called a closed loop control system.

6. Explain Fluidic Logic Control?

In many plants, closed loop control is achieved by electronic devices based on I different logic functionssuch as AND, OR, NOT and MEMORY.

Logic controls can be defined as design of control system based on reasoning arising out of deductive principle. However, the electronic control system is not only control system used in industries. If the pneumaticcontrol system using low pressure air is used to achieve the above logic control functions, then it is known asFluidic Logic Control.

7. What is fluidics?

Fluidics is the technology that utilizes fluid flow phenomena in components and circuits to perform a widevariety of control functions including sensing, logic and m more functions.

8. How pump cavitation is identified?

Cavitation is the inability of a pump to draw a full charge of oil either because of air leaks or restrictionsin the inlet line. When a pump starts to cavitate, its noise level increases and it may become very hot around theshaft and front bearing. Other symptoms of cavitation are erratic movement of cylinders, difficulty in building upfull pressure, and a milky appearance of the oil.

9. Write about leakage testing of air cylinders?

Piston seals and rod seals become worn to the point that cylinder performance (or) I efficiency isaffected. Leakage around the rod seal can easily be detected and the seal can be replaced. At that time, the rod

bearing which is usually brass, bronze (or) Teflon, It should also be replaced.

10. What is air receiver?

Air receiver is a large cylindrical vessel used to store high-pressure air from the compressor. Large surfacearea of the receiver dissipates the heat of compression (heat in the compressed air) to the surroundingatmosphere. It will have safety relief valve, pressure indicator and temperature switches.

7/25/2019 ME2305-AHP-5

3/3

11. What is meant by fluidics?

Fluidics is the branch of science, which deals with Liquids, Gaseous systems, Components, design, andapplications of above in the industries to perform useful work.

12. Name the major units of PLC?

1. Control processing unit (cpu)2. Programmer/ monitor (pm)3. Input/output moduel (I./O)

13. Define LCA?

Low cost automation (LCA) is defined as a technology that creates some degree of automation around theexisting equipment, tools and methods, using mostly the standard equipment available in the market.

14. Name the applications of low cost automation?

LCA can be applied in any manufacturing activity such as loading feeding, clamping, machining, welding,assembling and packing.

15.what are the features of LCA?

1. The automation of small to medium scale industries can be made viable.2. Since it is build using the existing resources in a systematic way, the investment risks are low.

Labour productivity can be enhanced subst p6+ antially.