Refrigeration & Equipment Engineering

9. SEMI TRO-SEA CLOSING MACHINE

SEMI TRO-SEA CLOSING MACHINE

Aim: To close one end of the flanged can body and measure the power transmission elements of a semi tro-sea closing machine.

Apparatus:

• Semi tro-sea closing machine
• Flanged can body
• Tachometer
• Outside caliper
• Measuring scale
• Thread (Nylon)
  

Working principle: The semi tro-sea closing is a foot operated one having a simple mechanism, compact structure and is easily adjustable for different can sizes. The seaming head is made up with two grooved rollers. In its simple mechanism the electric power from the driver pulley is transmitted to the driven pulley by ‘V’ belt. The power from the driven pulley is transmitted to the worm and worm shaft at the center as well as to the bevel gear at the end of the driven pulley shaft. The worm wheel has a short shaft on which two cams with grooved (seaming) rollers arms have fixed on both the sides. Now, due to the rotation of the driven pulley the grooved rollers come forward to do the seaming operation and go backward when top dead center and bottom dead center of cam profile is on the small roller of the arm.
Nearly 30to 40 seams per minute can be done using this machine.

The machine essentially consists of the following parts.

• Cast-iron body
• Electrical motor
• Pulleys
• Chuck
• Bevel gears
• Cam arrangement
• Worm and worm wheel
• Seaming head (first and second operation grooved roller)
  

Procedure:

• After observing the condition of the machine greasing, oiling and cleaning should be done if necessary.
• Verify whether chuck, seaming rollers are in the good condition or not if not may be replaced.
• Also verify whether chuck, seaming rollers are rotating properly or not.
• Place the flanged can with lid over the unscrewed base plate (Lifter) and raise the base plate so that the can with lid is at just level with the top edge of the chuck, then screw the nut. OR The distance equals the height of the can less the thickness of the chuck, then screw the nut.
• Switch on the machine.
• Engage the declutch lever and press the foot pedal firmly so that the operation rollers will come forward one after the other and complete the seaming operation.
• Take out Seamed can for the next operation.
• Switch off the machine after completion of the work.
  

Precautions: After releasing the foot pedal hold the rotating can loosely and while taking it out after the operation, never allow the can to fall on the floor to prevent damage to the flange of the can. Little greater pressure is given to the lifter especially while seaming large sized cans.

Observations: Record the following observations:

Sl.No.	Parameters
1.	Type of gear used (No.)
2.	No. of gear used (No.)
3.	No. of teeth on each gear (No.)
4.	Type of belt used
5.	No. of belt used (No.)
6.	Groove thickness of the first operation roller
7.	Groove thickness of the second operation roller
8.	Type of belt drive system used (cms)

Calculations:

1) Velocity ratio of belt drive

N₂

= ------------

N₁

d₁

= ------------

d₂

Where,
N₁ = Speed of the driver in rpm
N₂ = Speed of the driven in rpm
d₁ = Diameter of the driver in cm
d₂ = Diameter of the driven in cm

2) Length of the belt

(r₁ – r₂)²

L = (r₁ + r₂) + 2x + ------------

x

Where,
r₁ = radius of the driver pulley in cms
r₂ = radius of the driven pulley in cms
x = distance between the center of the pulley in cms

2 π NT

HP = ------------

4500

3) Diameter of the shaft

π

T = ------fsd³

16

Where,
Fs = Shear stress in Kg/ cm²
T = Torque in Kg-m
N = rpm
HP = Horse power
d = Diameter of driver shaft in cms

4) Calculation of seam thickness

T = 3+c+2+b+G
G = Total clearances existing in double seam the standard value of G=0.15mm
Tc = Thickness of Tin plate used in can ends
Tb = Thickness of the plate used for body