Irradiator Cruise Control

Posted on May 19, 2016

View PDF here.

Prepared By: Peter Veselovsky, P.Eng

The gradual decrease in speed in Gamma irradiators is inevitable. Typical compensation for Cobalt 60 decay of roughly 12% per year is either to purchase more Cobalt 60 or to increase irradiator cycle time. Cobalt top-up occurs once every 6 to 12 months, while cycle slowdown is traditionally applied to equipment once a month by manually applying set-points calculated in an Excel spreadsheet. This spreadsheet is designed by a sterilization engineer, and manual data entry is performed by an operator and verified by a Quality Assurance (QA) employee.

konnTRACK Process Controls Software offers a continuous compensation for the decay. At Konnexis, we playfully named it Irradiator Cruise Control. Our approach has a couple of advantages over the traditional method:

1.     Periodic cycle time setting performed manually has to be slow enough for the last day in the adjustment period while continuous adjustment has to be slow enough of the instantaneous cobalt activity. This results in a performance improvement of up to 1%, or revenue increase of $50,000; and

2.     Simplifies operation and eliminates manual timer setting due to Cobalt Decay that can be erroneous.

Similarly, irradiator speeds may have to be changed based on the product class that is run at any given time. Traditionally, this also involves a spreadsheet that calculates Cobalt decay and establishes cycle times based on dose maps. Subsequently, operators make data entries and a QA employee verifies them.

Needless to say, this is a complex process with potential for error and inefficiencies.


Figure 1: Slowdown in processing due to Cobalt 60 decay – Automatic vs manual cycle time compensation

konnTRACK Process Control software uses normalized cycle times that relate to product classes (also known as/or sterilization families). Normalized cycle times do not change when using this software. The operator simply selects a product family to be run from a list that has been entered into konnTRACK by QA. The system will continually calculate the cycle time based on the Cobalt’s current activity and the product family selected.

Note: To fully eliminate manual product selection and to further optimize processing of product families through your Irradiator, please check out the konnTRACK Product Tracking Software.