Safety first. Steam and hot concentrate cause severe burns. Isolate steam and product, release vacuum or pressure, and let the plant cool before you open inspection covers.
Symptoms
- Concentrate solids falling during the run at the same feed rate.
- Steam pressure or temperature difference rising to hold the same output.
- Burnt deposits or brown spots on the tubes after the run.
- Shorter time between cleanings than before.
Likely causes
- Product fouling. Proteins and minerals deposit on hot surfaces. The rate rises with temperature, preheating conditions and product quality.
- Poor liquid distribution. A blocked or uneven distributor leaves tubes partly dry. Dry areas burn product on fast.
- Vacuum and venting. Air leaks or poorly vented non-condensable gases reduce heat transfer and change boiling temperatures.
- Steam side. Wet steam, failed steam traps or condensate that does not drain take heating surface out of use.
- Incomplete cleaning. Deposits left after CIP give the next run a fouled start.
What to check, in order
- Compare feed rate, feed temperature and concentrate solids with a good run at the same point in time.
- Check vacuum level and condenser cooling water against your service documentation.
- Check steam traps and condensate drainage.
- After the run, inspect the distributor and the top of the tubes for blockage and uneven wetting.
- Review the last CIP: chemical strength, temperature, time and flow.
- Ask whether raw material or preheat conditions changed.
When to call a TPS engineer
Call a TPS engineer if capacity does not recover after a full CIP, if you find burnt deposits in a regular pattern, or before you change the run length or cleaning programme.
Ask LiveAccess
Ask with your feed rate, steam pressure, vacuum and concentrate solids at the start and end of the run. In the app you can also find a evaporation expert in the Expert Network and chat or call them.
This guide gives general checks. Settings, limits and procedures differ between machines: always use the values in your service documentation and your site procedures.
