While charging / shutting down the oven we require to heat / cool down the oven for sometimes.
How to shorten these time loses without affecting the quality of band and oven ?
It depends on the oven you use actually. Cyclotherm ovens take a long time to get heated up ( around 2 hours) so the same time is required for cooling down too. Therefore if you have an oven with frequent product changeover, you are effectively loosing a lot of productivity. Either this or if you decide to keep the burners on while changeover, it results in lot of loss of fuel and damage to the band.
However on the convection oven, you just need 15 mins for the burner to start up to reach its desired temp and also cooling down time is relatively shorter as well.
There are also features on todays convection ovens like automatic gap control system which is installed in the infeed of otherr oven which senses the incoming product and in case of a gap, it automatically reduces the burner temp to a certain min level and then when the products are sensed, it increases the temp to the desired set point. This is mostly possible on a convection oven.
What do you mean, to reduce the times?
All the process depends on the working temperature,The safest way is: to set a minimum temperature ( 100°-120°) in the automatic shut-off cycle, this system is independent of all factors related to production and work environment
in fact it is not easy to understand the question asked. However it is possible to apply from start production software or format changes, if you want to raise the temperature for a settable time or decrease it ... in short, you can do everything, but just understand that a tunnel oven has limits due from length and width ....
While charging the Oven you need to close the inspection windows, steam extraction dampers and any other heat leakage points to heat up the Oven faster.
For cooling down of the Oven faster you need to open the windows, dampers and keep the fans/blowers on till your required cooling temperature is achieved.
This is for any type of Oven irrespective of heat circulation method used
Thanks Mr. Rahul.
But that is my question.
If we open the side window, which are normally in the working side, will it affect the oven band ?
Opening side windows is not recommended it will result in trecking of band can damage the band If stuck.
Better is to keep shutting down temperatures at 100 C I have tried it in some cases there were no damage to band or oven recorded.