1. MANUFACTURING OF
PRESSURE COOKER
NAME ROLL NUMBER
1)K SAI KUMAR :B150701ME
2)V V A SRAVAN KUMAR :B151058ME
3)Y GOVARDHAN REDDY :B150111ME
4)T VAMSHI KRISHNA :B150876ME
5)R TARUN TEJA :B150732ME
3. INTRODUCTION
A PRESSURE COOKER COOKS FOOD FASTER THAN CONVENTIONAL POTS
AND SAVES ENERGY.
PRESSURE IS CREATED BY BOILING WATER OR OTHER LIQUID INSIDE A
CLOSED CONTAINER.
THE STEAM TRAPPED INCREASES THE INTERNAL PRESSURE AND ALLOWS
THE TEMPERATURE TO RISE.
THE PRESSURE IS GRADUALLY REDUCED AFTER USE SO THAT IT CAN BE
OPENED SAFELY.
4. MATERIALS USED FOR MANUFACTURING
PRESSURE COOKERS ARE MAINLY MADE UP OF STAINLESS STEEL AND
ALUMINUM
PROPERTIES STAINLESS STEEL ALUMINUM ALLOY
COMPOSITION 18%Cr,10%Ni,Fe Al 3003 or 3004
THERMAL CONDUCTIVITY 16 W/M K 162 W/M K
TENSILE STRENGTH 515 MPa 130 MPa
YIELD STRENGTH 205 MPa 125 MPa
SHEAR STRENGTH 83 MPa
BRINELL HARDNESS NUMBER 201 MPa 160-550 MPa
% ELONGATION 40% 10 %
5. MATERIALS USED FOR MANUFACTURING
ALUMINUM PRESSURE COOKERS ARE CHEAPER BUT ALUMINUM REACTS
WITH ACIDIC MATERIALS THERE BY CHANGING THE FLAVOUR OF COOKED
ITEMS.THEY ARE LESS DURABLE THAN STAINLESS STEEL COOKERS.
STAINLESS STEEL COOKERS ARE COSTLIER AND ARE PROVIDED WITH
THREELAYER OR COPPER CLAD BOTTOMS FOR UNIFORM HEATING BECAUSE
STAINLESS STEEL HAS A LOWER THERMAL CONDUCTIVITY.
SOME PRESSURE COOKERS ARE ALSO PROVIDED WITH A NONSTICK
INTERIOR.
GASKETS ARE MADE UP OF RUBBER OR SILICONE.
6. MANUFACTURING PROCESS
THE PROCESS STARTS WITH A STAINLESS STEEL OR ALUMINUM DISC .
GENERALLY THE THICKNESS OF THE DISC DEPENDS ON THE THERMAL
CONDUCTIVITY , INTENAL PRESSURE AND CAPACITY OF THE POT.
DIAMETER OF THE DISC DEPENDS ON CAPACITY OF POT.
THE DISK DIPPED IN A SUITABLE LUBRICANT TO AID THE FORMING
PROCESS.
COMMON LUBRICANTS USED ARE DRAWING OILS(TALLOW OR LARD
OIL),SOAP/FAT PASTE TYPE MATERIALS(5% SOAP,25% WATER,25% OIL AND 45%
SOLIDS).
7. MANUFACTURING PROCESS..
THE MAJOR OPERATION INVOLVED IS CUP DRAWING.
THE STAINLESS STEEL DISK IS DRAWN THROUGH AN INVERTED CIRCULAR
SHAPED DIE TO FORM A NICELY ROUNDED POT.
A CLEARENCE OF ABOUT 1.1t(THICKNESS) IS PROVIDED.
CUP DRAWING
8. SELECTION OF PRESS
THE DRAWING FORCE CAN BE ESTIMATED BY THE EQUATION
t=original blank thickness
TS=tensile strength(MPa)
Db= starting blank dia
Dp=punch dia
0.7 is a correction factor to account for friction
FROM THIS PRESS CAPACITY CAN BE ESTIMATED.
9. MANUFACTURING PROCESS..
A PUNCH CUTTER IS ALLOWED TO MAKE NOTCHES IN THE POT’S RIM.
THESE NOTCHES HELP IN INERLOCKING WITH LID HELPING IT TO HOLD
HIGH PRESSURE.
PUNCH CUTTING
10. MANUFACTURING PROCESS…
THEN AN ALUMINUM DISK IS DIPPED IN AN ALUMINUM SILICON SOLUTION
FOR A UNIFORM COAT.
THEN THIS DISK IS PLACED AT THE BOTTOM OF THE POT ON WHICH A
STAINLESS STEEL DISK IS PLACED.
THE THICKNESS OF BOTTOM DISC CAN BE UPTO 4.5mm.
11. MANUFACTURING PROCESS…
THEN THE BOTTOM OF THE POT IS HEATED TO A TEMPERATURE OF 1100ºF
THIS ACTIVATES THE ALUMINUM SILICON SOLUTION TO FUSE THE DISK TO
THE BOTTOM OF THE POT.
THE POT IS THEN COOLED BY DIPPING IN WATER.
THE RAGGED EDGES ARE TRIMMED OFF.
12. MANUFACTURING PROCESS…
THEN THE PRESSURE COOKER POTS ARE SENT TO A SPECIAL CHAMBER
WHERE THE GRINDING TOOLS POLISH THE SURFACES OF THE POT.
THEN THE POTS ARE WASHED THOROUGHLY TO REMOVE ANY RESIDUES.
GRINDING
13. MANUFACTURING OF LID…
THEEE PRESSING OPERATIONS ARE REQUIRED TO MAKE THE LID.
TWO HOLES ARE PUNCHED ON THE LID FOR TWO VALVES.
14. FIXING OTHER ACCESSORIES
TO INSTALL THE MAIN VALVE THE MAIN HOLE IS ALIGNED WITH A
RETAINING RING.
THE SPRING LOADED VALVE IS TIGHTLY SCREWED BY AN AUTOMATED
DEVICE.
SIMILARLY A BACKUP VALVE IS FIXED IN THE SMALLER HOLE.
THESE VALVES HELP IN PREVENTING EXPLOSION.
A PLASTIC COOKING GUIDE IS FIXED AROUND THE MAIN VALVE.
