110-509 PSC/EN
14
External Closed Loop Circulation
WARNING:
When connecting tubing to an external application, it is the user’s responsibility to make
sure that the tubing and fittings connected to the Circulator are suitable for the fluid being used and
the temperature range of operation.
CAUTION:
The Circulator’s bypass tubing is secured to the fluid inlet and outlet connections by high
temperature nylon hose clamps, which can be removed by carefully cutting them with diagonal
cutters.
CAUTION:
Secure the tubing to the inlet and outlet fittings using hose clamps with a minimum ID of
7/8 inch (22 mm). Do not operate the unit without hose clamps.
WARNING:
If the Circulating Bath will not be used for external circulation, the inlet and outlet ports
should remain connected using the Buna N bypass tubing provided with the unit.
The single speed pump on your Circulating Bath permits closed loop circulation to an external apparatus
via the ½ inch / 12.7 mm OD pump inlet and outlet ports on the rear of the MX Controller. To maintain
adequate flow, avoid restrictions in the tubing. If a higher flow rate is desired you can move the flow
adjuster toward a closed position as shown below.
The control stability of a closed loop system is better at the external apparatus than in the immediate
vicinity of the heater (provided the apparatus control point represents a constant load and is well
insulated). For example, if you circulate through a viscometer at 50°C the temperature variation observed
in the reservoir may be ±0.1°C, whereas in the viscometer it may be only ±0.05°C.
Although stability is better at the external apparatus control point, depending on the insulation and length
of tubing used, the accuracy of temperature may be slightly different than the temperature indicated in the
reservoir.
Connection to external devices which utilize a Quick Connect Coupling is not recommended due to
potential reduction in flow rate of circulating fluid, which may ultimately affect temperature stability at the
external device.
NOTE:
Coliform Baths are not equipped for external circulation.
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