Dairy Processing - January/February 2024 - 49

PRIORITIZING MAINTENANCE
One way dairy processors can judge the effectiveness
of their heat exchangers is by analyzing the time
between cleanings. As there are no moving parts in plate
and tubular heat exchangers, units should run the same
day-to-day with proper cleaning and maintenance.
Less fouling of a processor means longer run times
and easier cleaning.
The manual should be the primary reference point
for establishing safe operations and recommended
cleaning in place (CIP). For older machines, regular
maintenance is critical. Replacement parts should come
from a certified source, and repair work should be
performed in accredited facilities.
The recommended flow rate and corresponding pressure
drop should be included as part of the system design.
The CIP flow rate should not be assumed, as this can
vary greatly by the product being processed and the
manufacturer of the equipment.
Heat exchangers must be cleaned after every
product run and sanitized before every production
run. The proper CIP flow rate depends on the equipment's
requirements. For example, milk high-temperature-
short-time (HTST) processing will have a lower CIP flow
requirement than ice cream mix HTST. This is mainly due
to the difference in viscosity.
Uneven flow across the plate in a plate heat exchanger can
cause buildup and residue that can be difficult to clean and
thus can harbor bacteria. Plates developed to have an even
velocity will have a reduced amount of residue and be more
easily cleaned with CIP.
There needs to be a similar inspection every time heat
exchangers are sanitized. Something as simple as a broken
blade pin can introduce a rough surface for food and bacteria
to hide. Surface anomalies should be addressed and repaired
as a preventative action.
A heat exchanger that meets the 3-A standards
requirement should not have any crevices or pockets for
product to hide. Any surface anomaly - such as pitting,
rough welds, blistering and cracks - can become an area in
which contamination could occur.
It is strongly recommended to open the heat exchanger
after the first production run during commissioning to ensure
the unit is cleaning, then progressively extending the time
between openings. When opening the heat exchanger for
inspection, it is wise to inspect the product connections and
the entire heat transfer surface.
Heat exchangers are an important part of CIP processes,
in which cleaning of system components takes place without
APV ParaTube Tubular Heat Exchanger from SPX Flow.
having to dismantle or open the equipment for cleaning. The
devices heat the cleaning water and solutions to a consistent
temperature to aid in the removal of residue. Newer heat
exchanger designs include units that are easier to clean and
simpler to open for inspection.
Periodic visual inspections will ensure CIP systems are
efficient. Operators also should inspect the cooling and
heating media for such abnormalities as scaling, rusting
or erosion.
Dairy processors can utilize control systems to
continuously monitor valves and pumps. Any deviation from
regular operating parameters means something is wrong,
warranting an inspection. Having to run hotter and colder
media temperatures compared to when the unit was new
could be a sign of fouling and the need for cleaning.
Additionally, when equipment is fitted with a remote
access and monitoring system, the manufacturer can access
key information and metrics, and log on and discover any
potential issues and quickly identify their resolution when
necessary. Using the manufacturer's technical expertise can
save time and money by identifying problems and solutions
quickly and without incurring costly site visits.
DAIRYPROCESSING.COM | JAN-FEB 2024 49
SPX Flow
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Dairy Processing - January/February 2024

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