Mr. Prabhakar Wawge, Area Manager, Peenya Alloys Pvt. Ltd.

206, Patil Plaza, Parvati, Pune 411009 ( MS ) India

Introduction

In any industry, heating, cooling and compressed air the costliest part, which affects the production cost of any product. There are three types of indirect heat requirement or the requirement of heat can be divided in the three main categories.

1 low temp. 40 — 60 Deg

2 Medium temp. 80 — 150 deg.

3 High Temp applications — above 150

Solar Flat Collectors have been proven for the use of solar energy for medium temp. application in hotels, boiler feed water preheating, dairy for pasteurization and some other indirect heating applications. There is another neglected area of application of Solar Flat Plate collector is heat treatment for powder coating plants where heat requirement is bet 50 Deg C — 70 Deg C. In any automobile industry the aesthetic or look of the vehicle place a very important role as far as the sale is concern (after the mechanical performance). The aesthetic means the body and colour of the vehicle. To get a long lasting good quality color, the powder coating procedure plays a major role. Before powder coating there is requirement of different chemical treatment for the removal of rust, grease and other cleaning of the specific sheet metal body parts. The time duration and chemical composition is depends on the selection of body material. A proven method of a chemical treatment is seven / eight tank process.

The common system of heating chemicals is by way of electrical heaters, by diesel or other fuel fired boilers. This increases the cost of heat treatment process due the high cost of electricity ( for industries rate of electricity is 1.5 to 2 times than the domestic rate ) or oils. This can be replaced by Solar water heating system which can efficiently generate the temp of liquid upto 85 Deg C.

1.History

All automobile bodies are made up of CRCA ( cold rolled cold annealed ) sheets. To prevent from atmospheric reaction the manufacturer usesupplier of CRCA sheet use to send the sheets with oil coat. During pressing operations there are chances of getting different impurities on the finished surface which is to be treated before coating. Seven/Eight Tank Process: There are eight tanks having different chemicals to remove the oil & rusting and operations are performed is given below.

1. Emulsification: This is a hand operation and the emulsifier is applied to the surface of the job to reduce the stickiness of the oil so that the cold degreasing will be more effective. This is a floor operation.

2. Tank 1 Cold degreasing: This is cold operation and do not require heating this tank.

3. Tank 2 — Hot degreasing: In this operation the temp. of chemical is to be maintained is 55-60 Deg C. The dipping time of each job is 10 min.

4. Tank 3 — Water Rinse — to extract the released oil due the last treatment. This is cold operation.

5. Tank 4 — Water Rinse — to remove the oil remained in the last treatment. This is also cold operation.

6. Tank 5 — Activation — This is a cold operation and it has been performed to reduce the prospecting time.

7. Tank 6 — Phospheting — In this tank the phospheting chemical is to be maintain betn 35 — 40 Deg. C. The job is to be kept in this booth for 5-7 min.

8. Tank 7- Water Rinse — Cold operation booth and is to be done to remove phospheting chemical remained on the surface of the job.

9. Tank 8 — Passivation — In this tank the water is to be kept bet 65 — 70 Deg C. The operation time is of 1 min.

All the tanks are of 3000 ltrs. capacity and the three tanks which are having heated chemicals are insulated.

This was a specific requirement of solar water heating system for heating chemical of heat treatment tank chemical at least for one shift from M/s Chaphekar Suspensions Pvt. Ltd. Pune. The product to be treated was the trolley of Bajaj make goods tempo (5 wheeler) . We have designed the system to meet the requirement of 60 trolleys per day. (Between 9.30 am — 6.30 pm). Schematic Diagram 1

Air Vent

SCHEMATIC DIAGRAM OF SEVEN TANK PROCESS HEATING

BY SOLAR