A plate evaporator trial should include the cleaning handoff

Record the product condition at the start, not a nominal description

A trial record should identify the actual feed lot and its preparation: the liquid, its inlet concentration, the time and temperature history before the evaporator, and any screening, clarification or separation step. If the feed contains pulp, fibres, oil traces or suspended material, record what was present and what was removed. “Juice” or “coconut water” alone is not a specification.

The same discipline applies to the utility and operating conditions. Record the heating supply, cooling supply and vacuum condition actually used, together with the intended product flow and the sampling points. The Tetra Pak evaporator chapter notes that product properties such as viscosity and heat stability limit how far concentration can be pushed, and that the operating design must consider temperature and holding time. A trial that records only the final concentration cannot show which condition produced it.

Photographs and retained samples can support the record, but they do not replace measured values. Keep the feed sample, the concentrate sample and the operating log linked to the same run. If a result is later questioned, the first thing needed is a traceable starting condition.

Track concentration observations through the run

The trial should state how concentration is measured and how often. A refractometer reading, a solids determination and a density measurement are not interchangeable without a stated basis. Record the sample point, the temperature at sampling and any dilution or handling before analysis. For a food liquid, the relationship between a Brix reading and non-volatile solids may need product-specific confirmation.

Observe the equipment behaviour that accompanies the concentration change: feed rate, recirculation or transfer status, pressures, temperatures, levels, foaming and any alarms. A stable outlet number at one moment does not show that the system holds the intended condition across the run. The useful evidence is a set of observations that can be compared with the operating log and the feed record.

At the end of the run, collect the concentrate and note how it is cooled, held or discharged. The evaporator is a concentration package, not a complete preservation or packaging line. If the downstream route affects the product, include it in the trial boundary or state clearly that it was outside the test.

Inspect the product passage before cleaning obscures the evidence

After the run, inspect the accessible product-side surfaces before cleaning begins. Record what is visible, where it appeared and how difficult it was to reach. The plate pack, separator, pipe connections, pump areas and any sampling or drain points are different inspection locations; a clean-looking frame does not establish the condition inside the passage.

The Tetra Pak cleaning chapter describes deposits on heated surfaces and notes that equipment must be designed so cleaning liquid can reach all surfaces, without dead ends or pockets that cannot drain. Those are design and inspection criteria, not a guarantee supplied by a cleaning chemical. The trial should identify the actual access points, the tools needed and the time required to open or inspect them.

If the design does not allow useful inspection without major dismantling, that is a finding to resolve before acceptance. The buyer should know which checks are routine, which require production downtime, and which are outside the supplier’s recommended procedure. Put those answers in the trial report rather than relying on an operator’s recollection.

Assign the CIP boundary and the responsibilities on both sides

Cleaning-in-place circulates cleaning liquid through a defined circuit. The dairy handbook describes CIP circuits grouped by residue type, material compatibility, simultaneous availability and contamination risk. It also describes stages such as product recovery, pre-rinsing, detergent circulation, rinsing and disinfection, with critical parameters including concentration, temperature, flow and time. These are dairy examples; the actual programme for another product must be established for that product and equipment.

The commercial question is where the CIP system ends and the evaporator begins. Identify the supply connection, return connection, drain, vent, sampling point and any excluded section. State who supplies the cleaning station, who sets the programme, who confirms material compatibility, and who is responsible for cleaning the transfer line between the evaporator and the next operation. “The plant will handle CIP” is not a boundary.

Also separate closed-circuit cleaning from open cleaning. A CIP circuit can circulate through pipes, pumps, heat exchangers and vessels, but external surfaces, open tanks or dismantled parts may need a different procedure. The trial handoff should say which parts are cleaned in place, which are cleaned out of place, and how the equipment is returned to production afterward.

Define acceptance evidence that can be repeated

The cleaning chapter lists visual inspection, microbiological swabbing and ATP testing as ways to verify cleaning effect, and notes that critical CIP parameters should be monitored and recorded. It also distinguishes verification of a cleaning result from validation of a procedure that repeatedly produces an acceptable result. That distinction is useful in a trial: one clean inspection is not the same as a documented, repeatable handoff.

Agree in advance which checks will be performed, where samples will be taken, who interprets the result and what happens if a check fails. If the product is not dairy, do not transplant a dairy cleaning schedule or a dairy acceptance limit. Ask for the basis of the proposed method and confirm it with the responsible food-safety and quality functions.

A practical acceptance package can include the feed and concentrate records, the operating log, the post-run inspection notes, the CIP programme and parameter record, the verification results and a list of open actions. It should also identify the person who accepts each item and the revision date. That package is more useful than a claim that the equipment is “CIP compatible”.

The handoff checklist

A plate evaporator trial is more informative when it tests the product route and the cleaning handoff together. The objective is not to promise a particular cleaning result before the product and equipment are known. It is to make the result measurable, assign the interfaces and leave the buyer with evidence that can be reviewed after the trial team has left.

• Feed lot, preparation, inlet concentration and any retained or removed solids.
• Operating conditions and the sampling plan used through the concentration run.
• Post-run inspection points, access method and observations before cleaning.
• CIP supply and return boundary, circuit grouping and excluded equipment.
• Cleaning media, materials compatibility, critical parameters and responsible operators.
• Verification method, acceptance criteria, records and owners for every open action.
• Spares, training and the procedure for returning the equipment to production after cleaning.