Technical Bulletin
935/970 Oven Chain Tension and Adjustment
Product No. 1210-20
Date Reissued: 27 May, 2008
TB No. 01.00 Rev. 1
Keep this T B With the Operations And Maintenance Manual.
NOTE
Before Maintenance please read and understand all Safety
Precautions in your Operations and Maintenance Manual.
A new Oven chain will need to be adjusted after the first (3) months of
operation refer to your Operations and Maintenance Manual (see
Preventative Maintenance table).
0.1
935/970 Oven Chain Tension Adjustment
Loose Chain; A chain that is too loose may kink (two pitches lifting up on each other) as it
leaves the sprockets or shoes. This can cause the conveyor to jam.
Tight Chain; A chain that is too tight can cause premature wearing out of the chains,
sprockets and shoes. This can also cause the conveyor to Surge.
The chain tension is increased by turning adjustment nuts (E) and (F) in a clock-wise
direction. They must be adjusted evenly so that spring yoke remains parallel with carriage.
This can be checked by being sure that spring yoke is the same distance top and bottom
from carriage (see Figure 0.3.2: "935/970 Chain Tension Adjustment", on page -4).
0.2
Setting Chain Tensions
Occasionally the chains may surge slightly when the oven is cold. This is normal and
should stop once the oven has reached baking temperatures provided the chains are
properly tensioned and lubricated.
Since chain tension must only be determined by observation, it requires a certain degree of
skill and patience to do the job properly. There is only one place where the chain tension
can be observed and that is at the drive end. In any case, the proper tension is indicated
when the chain makes a gentle arc as it comes off the rear sprockets or shoe onto the rails
(see Figure 0.3.3: "935/970 Chain Tension Adjustment", on page -4).
The conveyor chains on either side of the oven are adjusted independently of each other.
The amount of adjustment needed on the left hand (double chain) side of the oven will
differ from that on the right hand (single chain) side of the oven.
•
•
Take up unit No. 1 adjusts the double chain side
Take up unit No. 2 adjusts the single chain side.
Turkington USA - P.O. Box 1678 - 1200 West Ash St. - Goldsboro NC - T 919-735-4570 - F 919-735-5275
06 June 2008
Every (3) months, stop a “Z” bar at the (3) O’clock position on the sprocket/shoe as shown
in (see Figure 0.3.3: "935/970 Chain Tension Adjustment", on page -4). Check the rollers of
both chains, they should not be able to roll. The shoe should be adjusted to accommodate
for this condition.
Start-up Chain Tension Setting
1).
2).
NOTE
The starting point dimension of 16 1/2” (Dim A) is for the spring compression
at start-up only (see Figure 0.3.2: "935/970 Chain Tension Adjustment", on page -4).
The spring tension is set with the oven at temperature and full of product.
When replacing chain on an existing oven ensure the heat shield does not rap
around the post at this time by removing the post or cutting the heat shield. This
will prevent potential binding of the take-up.
3).
4).
Open the back doors and look at the chain coming off the rear sprockets, the
chain should start breaking loose from the sprocket at the 4:30 to 5:00 position,
you should see the chain roller leave the sprocket by a 1/8” gap at the 6:00
position (see Figure 0.2.1: "Chain Leaving Sprocket", on page -2).
The chain coming off the double chain side sprocket and the rear shoe should
look the same, if not you will need to make this adjustment on a down day.
Figure 0.2.1: Chain Leaving Sprocket
1/8 GAP
MINIMUM GAP VISIBLE AT
6:00 O’CLOCK POSITION
BETWEEN ROLLER AND
SPROCKET
NOTE
SEPARATION OF ROLLER
FROM SPROCKET VISIBLE
HERE
Do not over tension this shoe because it will cause the chain to track off at the
front of the oven.
5).
NOTE
1/16 GAP
Check the chain about 8 to 16 inches after the sprockets on both sides of the
oven, make sure the chain does not look as if it wants to start kinking up (two
pitches lifting up on each other) if this happens then tighten up on the springs
until the chain lays back down on the tracks.
After making adjustments on the take-ups watch the chains for 1 hour to ensure
that the chain is not trying to kink up.
Keep both springs top and bottom compressed to the same length, this will insure
that the take-up carriages move back evenly without binding.
Spring tensions vary from oven to oven and this is the only way to set the correct
spring tension for your oven.
page -2
Turkington USA
06 June 2008
0.3
Maintaining Chain Tension
It Is The Customers Responsibility:
NOTE
To have Maintenance monitor the carriage positions and keep the
chains stretching evenly from side to side, THIS WILL
SIGNIFICANTLY EXTEND THE LIFE OF THE OVEN CHAIN.
TO TURN THE BURNERS AND THE MAIN CONVEYOR CHAIN
DRIVE OFF IMMEDIATELY AFTER PRODUCTION, the exhausters
and the coloraiders will run until the oven drops to 200° and after that
they can be turned OFF.
If the oven chain is not turned OFF and is running hot to cold the chain
starts shrinking and the oven springs are compressing more than normal.
Turkington USA strain gauge readings show an increase of 500 ft/lbs. of
running pressure when an oven chain is running during cool down. THIS
ACCELERATES THE CHAIN WEAR.
Use the following procedure for Maintaining Chain Tension for your oven:
1).
First down day, Attach a clip board on each side of the oven and record the following
(see Figure 0.3.2: "935/970 Chain Tension Adjustment", on page -4):
2).
a).
When the oven has cooled down and is shut off, measure and record the
compressed spring lengths (Dim A) on both sides of the oven. This
measurement is the starting point for maintaining chain tensions.
b).
Date measurements taken
c).
Carriage take-up measurement (Dim B)
Every three months:
a).
Measure and record Carriage take-up measurement (Dim B) on both sides of
oven and compare.
b).
If the take-up carriage is longer on one side or the other, the following
adjustments are needed on the springs:
If the single chain side carriage measured at 5" and the double chain side
was at 4 3/4” this means the single chain side is 1/2” longer than the double
chain side. If double chain side was longer... reverse the following
procedure.
NOTE
Tension Adjustment
page -3
1).
On the double chain side take-up, tighten the springs up one full turn.
2).
Be sure to write this down on the clip board and the date.
3).
Three months after this adjustment take the measurements again and
check to see if the chains are stretching back in line with each other.
4).
If not, make another adjustment (repeat the above).
Turkington USA
06 June 2008
Figure 0.3.2: 935/970 Chain Tension Adjustment
DIM - B
CARRIAGE TAKE-UP
FRAME
SPRING
YOKE
DIM - A
Figure 0.3.3: 935/970 Chain Tension Adjustment
STABILIZER BAR
AT 3 O’CLOCK
CHAIN CAN BUCKLE
Ref 2394-200
page -4
Turkington USA