Depyrogenating of wet vials

Hi Guys

Looking for your feedback for the following question:

I am having a issue with the depyrogenating of wet vials. A large portion of the vials are coming out scored-scratched. It seems that they are fusing together during the run. Could you provide any suggestions on how I can prevent this from happening?


Dear Friend,
This happens when there is a problem in the heating elements which run more than the pre-requisite temperature.
Normally Vials after washing are run thru the depyrogenating (Heating/drying) chamber on conveyer belt for a residense time of 3 to 4 minutes.The length of this run will be 2.5 feet to 3 feet depending upon the capacities one operates. Most of the operators run at 315C to 330C.
At times the temperature shown on your PLC is not correct.
My suggestion is check the temperature in the chamber by probes physically than depending up on the PLC.There is a serious problem of over shooting.Then if it is found the PLC should be reprogrammed and temperature must be adjusted.

Second serious reason might be usage of Soda Lime vials or Type III vials causes this sort of a serious problems.If you run such vials ,decrease the temperatures to a desired level and increase the residence time in Heating Chamber by decreasing the conveyer speed.

Another serious problem takes in some 3rd world countries is that they use reused vials which have no specification of types.They are all mixture of Type-1, Type-2 & Type-3 vials.In such an event this happens.The manufcaturers try to reduce the cost by pumping low quality products. But ultimately such things happens.

This is based on my previous experience. I will be glad some more experts join and give inputs too.

This problem is occurring in a depyro oven not tunnel. All vials used are type-1. PLC temp has been check for accuracy and operating correctly. Has anyone encountered this problem before?

We had this issue before in vials type-1, the reason in our case was due to the bad ore poor siliconate of vials. Have you assessed this issue?

Thanks for the responses guys, we will look into them immediately