to be gradually slowed down together
to avoid imbalance pressure within the
plates.
Sometimes, there are cases where
pressure builds up in one side of the
flow. This might due to many reasons.
One of the reasons is due to unexpected
dirt or particles penetrating into the
system and choke the PHE. To avoid
this, install a filter/strainer before the
PHE. This will help to block unexpected
objects from entering the PHE and
blocking the flow. Then, periodically
check and clean the filters/strainer.
Once in a while, leaking occurs due
to the tie-bars not tighten properly.
The tie-bars are the thick metal rod
that holds the plates between the PHE
frames.
Since the plates are connected by
gaskets, the gasket physical property
may change after the PHE is in
operation for some time. This happens
because the gaskets are continuously
exposed to hot temperature of the fluid.
Therefore, to avoid this, check plate
tightening dimensions and the integrity
of the frame, tie-bars, etc periodically.
Erosion of plates is another point of
concern. Though plates are normally
made of stainless steel, there are
situations where certain area around the
plate becomes thinner and thinner.
As a consequence that particular area
experiences pitting and resulted to
leakages.
This happens because some of the
plates arranged in the PHE experience
more pressure than the others due to its
position.
These plates become more fragile
because of the flow momentum hitting
on it continuously.
Therefore, PHE operators/engineers
need to identify this plate and replace it
when it becomes thinner.
Another way to prevent this is to avoid
flow rate beyond the recommended
limit. Consult the PHE design
specification for this data.
Q6: W hat are the plans for
the future , from the industry
stand point ?
A: This question is almost similar to the
previous one. Anyway, plans for the
future include making the PHE capable
of tolerating high temperature. This can
be done by developing a more strong
and durable gasket.
This is the challenge for materials and
polymer engineers. PHE is already a
brilliant piece of heat exchange device
and because it depends very much on
gaskets, it is the gaskets that need to be
further improved.
There are also issues of the safety
and health of the gasket material.
This is a concern especially in food
industry. Gasket made of asbestos can
be dangerous for health. Therefore,
designing and creating a safer and
healthier gasket is imperative.