Armfield PCT40 - Page 146

Armfield Instruction Manual
140
Using a length of tubing with a quick release fitting at both ends, connect the PSV to
the upper fitting on the side of the small process vessel. Ensure that the lower fitting
on the side of the process vessel is not connected.
Close the drain valve on the process vessel.
Run the PCT40 software and select ‘Section 6: Temperature Control (direct
continuous heating)’.
In the software, set the PSV to 100% and watch as the small process vessel fills with
water.
Wait until the coil inside the vessel is fully covered with water, then set the PSV to
0%.
Check that the drain valve on the end of the plinth is open and that it is connected to
a suitable drain.
Select a second length of tubing with a self-sealing fitting on one end and an open
end at the other, and direct the open end to a suitable drain. Connect the quick-
release fitting to the lower connection on the side of the small process vessel. Water
will drain from the free end. Half close the drain valve on the end of the tube.
In the software, increase the PSV value using the arrow keys until the water level in
the process vessel is stable and covers the coil. Adjust the drain valve so that the
water level in the vessel remains constant and covers the coil at a PSV setting of
approximately 50%. The apparatus should not be left unattended, to ensure the
process vessel does not overflow or run dry.
Procedure
SAFETY NOTE: During this exercise the apparatus may reach temperatures hot
enough to cause burns or scalds. Do not touch the process vessel during the
exercise, or remove the coil or sensors from within the vessel. Allow the apparatus to
cool before draining the water or disconnecting any of the tubes from the process
vessel.
In the PCT40 software, enter a set point value for the temperature of 30 degrees
centigrade. If the temperature of the local mains water supply is close to 30°C then a
higher set point value may be chosen, such as 40°C.
Set the PID values for the controller in the appropriate boxes in the software.
Suggested starting values are Proportional Band (P) of 100%, Integral Time Constant
(I) of 0s and Differential Time Constant (D) of 0s.
Select ‘Configure...’ from the Sample menu. Set the software to Automatic logging,
with a sample interval of 10 seconds and Continuous duration.
Select the
icon to begin data logging.
Log the temperature within the vessel for 10 minutes, then select the
icon to stop
logging.