TECHNICAL
1
As can be seen from the above information, we are
all at risk. Especially now that summer is coming, and
restaurants are once again starting to use those misting
systems that have been lying dormant and sitting in the
sun giving it plenty of time to breed those lovely and
willing Legionella bacteria.
Most sports/gym facilities also use circulating blended
hot water kept at a constant 38-42 o C. This temperature
range is a good safe temperature to prevent scalding of
any user but, it is also the ideal breading temperature for
any Legionella spores present in the circulatory system.
Any instance that uses a circulatory blended water supply
should do regular maintenance. This would include
decommissioning the system and raising the temperature
to above 60 o C for half an hour. But as South Africans we
do not schedule maintenance as a rule so how can we
make sure that we do not get infected?
The electronic hybrid mixing valve combines the typical
function of the mechanical thermostatic mixing valve and
the management efficiency of an electronic mixing valve in
a single device.
The thermostatic mixing valve uses the mechanical action
performed by the internal control thermostatic element,
which responds promptly to any variation in temperature,
pressure and inlet flow rate to quickly restore the mixed
water temperature value at the outlet.
This standard mixing valve is effectively handled by a
motorised actuator that, upon the signal coming from the
temperature probes and under the control of a specific
regulator, changes the mixed water temperature set
position.
We need to design these systems in such a way that
the cleansing cycle is done automatically without human
intervention. One such a method is to use an automated
cleansing system like the LEGIOMIX that is supplied by
Calafrica.
LEGIOMIX, supplied by Calafrica
"Persons become infected by breathing in
water droplets containing the Legionella
bacteria. Water droplets are generated by
spraying or bubbling air through water in
which the bacteria are present."
The electronic regulator, directly on the actuator, allows
the mixed water temperature control according to different
functional programs, both for normal control and for the
thermal disinfection for the prevention of Legionella.
An optional memory system allows recording of every
minute of flow temperature, return temperature, alarm and
functional statuses, useful for monitoring the operating
status of the entire system.
Appropriate relays are used to manage the alarms and
external appliances, for example for loading accumulation
hot water and switching on/off the recirculation pump.
The regulator is fitted for remote control with specific
transmission protocols such as MODBUS, through optional
board, for use in Building Management Systems (BMS)
So, in a nutshell we need to join the 4th Industrial
Revolution and to start using current day technology
available to us so that we can ensure our own and
others safety.
For any further information on this product please feel free
to contact the writer. PA
January 2020 Volume 25 I Number 11
www.plumbingafrica.co.za