Tunnel Pasteurizer OEE: Heat Zones, Blocked Time and Held Product

Key takeaways

• A tunnel pasteurizer's biggest loss is often not its own: it is blocked time from the labeller and packer after it.
• Its own stops are inlet jams, deck or belt faults and waits for zones to reach temperature.
• It holds a lot of product inside, so one deviation can put many containers on hold.
• Code blocked time, own faults and temperature waits apart.
• Pasteurization units are a product safety and quality target; never trade them for OEE.

Tunnel pasteurizer OEE measures the long machine between the filler and the labeller on many beer and juice lines: how long it runs, how close to its rated speed, and how much product comes out within its pasteurization target. Its losses are inlet jams, belt faults, temperature waits after stops, held product, and above all blocked time caused by the machines after it.

Fabrico, an OEE and light MES platform, logs each stop with its reason and keeps own stops apart from blocked time, so the pasteurizer is not blamed for the labeller's faults. This guide covers where the pasteurizer's time goes, how to measure it, why held product matters, and a worked shift.

Where does the tunnel pasteurizer's time go?

Filled and closed containers enter at the inlet, travel on a belt or deck through heating, holding and cooling zones where water is sprayed over them, and leave toward the labeller. The pasteurizer counts the heat each container receives in pasteurization units; our guide to pasteurization units explains the calculation.

How do you measure Availability, Performance and Quality on a tunnel pasteurizer?

• Availability = run time / planned production time. Own faults and temperature waits reduce it; in the full view, so do blocked and starved time.
• Performance = containers out / (run time x rated containers a minute). The belt speed is usually linked to the line, so Performance follows the filler.
• Quality = containers released / containers processed. Product held or rejected because it fell outside the pasteurization target counts against it.

Pasteurizers usually manage stops by adjusting zone temperatures, so product inside is not over or under treated. When that is not enough, product may be held for a quality decision. Follow your plant's quality rules; never shorten treatment to improve the figure.

Why does the pasteurizer hold so much product at once?

Little's law gives the answer: units inside = rate x time inside. A pasteurizer that takes 50 minutes from inlet to outlet on a line running 400 bottles a minute holds 400 x 50 = 20,000 bottles at any moment.

That has two effects. A stop downstream backs up into a machine full of product, and the zones must handle it. And a quality deviation can affect thousands of containers, not dozens. That is why held product deserves its own code and its own price, next to the minutes.

How do you separate the pasteurizer's own stops from line effects?

1. Read the outfeed when the belt stops: containers backed up means blocked, charged to the labeller or the packer.
2. Code temperature waits apart from mechanical faults.
3. Report Availability twice: all causes, and own causes only.
4. Track held product per event, with the reason and the quantity.

Our guide to starvation and blocking shows how to charge blocked minutes, and labeller OEE covers the machine that most often blocks a pasteurizer.

A worked shift on a tunnel pasteurizer

Sample line (illustrative numbers, not a customer): a beer bottling line running 400 bottles a minute through a tunnel pasteurizer, with a 2 minute buffer between the filler and the pasteurizer inlet. The shift has 450 minutes of planned production time, and the contribution margin is $0.10 a bottle, or €0.10 in a euro plant.

• Availability, all causes = 398 / 450 = 88.4%.
• Availability, own causes only = (450 minus 30) / 450 = 420 / 450 = 93.3%. The biggest single loss belongs to the labeller.
• Quality: 159,200 bottles processed, 1,200 held after the belt fault and later scrapped: 158,000 / 159,200 = 99.2%.
• Which own stops reached the filler: the inlet jams ended inside the 2 minute buffer; the belt fault blocked the filler for 8 minus 2 = 6 minutes and the temperature wait for 5 minus 2 = 3. That is 9 filler minutes x 400 = 3,600 bottles, at $0.10 = $360.
• The held bottles: 1,200 x $0.10 margin = $120 of margin, plus the product and packaging cost of 1,200 scrapped bottles.

Ranked as one event, the belt fault (stop, temperature wait and held product) is the pasteurizer's biggest own loss. But the labeller's 30 blocked minutes are bigger still, and they belong on the labeller's list.

Which mistakes do plants make with pasteurizer OEE?

• Charging blocked time to the pasteurizer, so the labeller's faults never get fixed.
• No code for temperature waits, so restart losses hide in "pasteurizer stopped".
• Counting held product only in quality reports, never next to the stop that caused it.
• Treating the pasteurization target as something to trade for speed. It is a product safety and quality limit.
• Comparing the pasteurizer's OEE with short machines without noting how much product it holds.

Where Fabrico fits

Fabrico is a computer vision enabled Manufacturing Performance Platform. OEE and light MES come first: automatic downtime logging that keeps own stops and blocked time apart, and OEE live by line and shift.

• The operator confirms the reason in one tap, so a belt fault and a temperature wait get different codes.
• A camera clip as evidence for a stop, where a camera watches the inlet or the outfeed.
• Losses priced in money and ranked, held product included.
• One view across plants for pasteurized lines on different sites.

You start with a pilot on one line, with a baseline and a decision date agreed in advance. There is no free plan and there are no tiers: each plant gets a quote. See how stops are captured on our computer vision OEE page.

Frequently asked questions

How do you calculate tunnel pasteurizer OEE?

Availability is run time over planned production time, Performance is containers out over what it could process at rated speed, and Quality is containers released over containers processed. Multiply the three.

Why is my pasteurizer's Availability low?

Often because of blocked time from the labeller or packer after it. Split blocked time from own stops before you judge the pasteurizer.

What happens to product inside the pasteurizer during a stop?

Most pasteurizers adjust zone temperatures to protect it. If product falls outside the target, it is held for a quality decision under your plant's rules.

Should held product count in OEE?

Yes, as a Quality loss when it is scrapped. Also record it next to the stop that caused it, so the event is priced as a whole.

Can I shorten pasteurization to improve OEE?

No. The pasteurization target is a product safety and quality limit. Improve the stops around it instead.

See your pasteurizer's losses in a demo

Bring one line and its current downtime log. We will show the pasteurizer's own stops, its blocked time and what each one cost.

Request a demo · Contact us