With a standard (single) tube plate with the welded tube
is in contact with the service fluid chamber/s
Preventing product
contamination with double
tube plate heat exchangers
By Matt Hale, International Sales & Marketing
Director, HRS Heat Exchangers
Ensuring product safety is the number is the quality of construction. Welding between the product and the service
one priority for any food or drink producer, needs to be precise and joints (whether medium (heating or cooling) due to
and a key aspect of this is avoiding rolled or welded) need to be smooth to leakage in tubular heat exchangers. The
contamination during production. prevent product fouling or lodging of first is to maintain a positive pressure
Equipment design and construction plays product, while also being strong enough difference between the product and
a key role in achieving this, and the heat to maintain integrity under pressure. the service fluid, so that should a leak
exchangers used for processes such as Most manufacturers will be happy to occur, the product will always flow into
pasteurisation and sterilisation are no arrange for you to see their production the service fluid rather than vice-versa.
exception. facilities and to provide information on However, in order to be successful this
their fabrication processes and standards. pressure differential must be maintained
There are three main elements to
preventing contamination occurring in The type of heat exchanger and its design
tubular heat exchangers: production capacity will determine the number of
quality, system design, and system tubes. At some point during the design
maintenance. process, the tubes will need to be
When it comes to quality, you generally
get what you pay for. If a quotation for a
new heat exchanger seems to be much
lower than others, be sure to check the
specification, particularly the materials
that are being used. Not only is the
supported and attached to the body of
monitoring systems must be included in
the heat exchanger. It also adds a further
level of complication when designing the
operating pressures for the equipment.
the heat exchanger – usually at the ends. The second option is to introduce
The tube plate (sometimes known as the a physical separation between two
tube sheet) not only supports the tubes, different tube plates; one for the product
but usually provides a barrier between and one for the service fluid. This means
the product and service fluid. that in the event of a leak from either the
quality of materials important (such as In terms of design there are two main
the use of stainless steel), but so too methods to prevent cross contamination
8 FDPP - www.fdpp.co.uk
at all times, and appropriate sensors and
service fluid or the product, the material
flows into a safety container or other
vessel and no mixing of the two materials