Bio-Rad CHEF-DR II System - Manual (Page 7)

The Cooling Module can now be added to the CHEF buffer circulation system as
follows (see figure 2):
1) Attach the buffer inflow tube (3/8" tube from the left front connector of the electrophoresis
chamber) to the reducer on the end of the tubing attached to the “FLOW IN” port. The
maximum total recommended length of tubing from the chamber connector to the “FLOW
IN” port is 4 feet.
2) Attach the length of tubing from the “FLOW OUT” port of the Cooling Module to the
inflow port of the recirculating pump.
3) The maximum total recommended length of tubing from the outflow port of the
recirculating pump to the electrophoresis chamber is 4 feet. Cooling capacity and
efficiency will increase if shorter overall lengths of tubing are used.
This configuration is recommended (as compared to having the buffer flow through the
pump first into the Cooling Module) for the following reason. Residual buffer (from a
previous run) can freeze in the heat exchanger of the Cooling Module if it is turned on, but
the recirculating pump is not. This frozen buffer will block the flow of buffer from the pump
to the Cooling Module, and may cause the tubing between the pump and Cooling Module to
come loose or burst. This could result in leakage of gel buffer from the system. In the
recommended configuration, no buffer will be drawn into the pump if a blockage occurs.
Fig. 2. Schematic diagram of Cooling Module installation in CHEF-DR II, CHEF-DR III, GenePath
or CHEF Mapper system.
5.2 Electrophoresis Chamber Internal Temperature Probe
The internal temperature probe monitors buffer temperature in the electrophoresis
chamber. If the electrophoresis cell’s internal temperature probe is connected to the Cooling
Module, buffer temperature will be automatically monitored at the cell’s internal probe. There
is a 9-pin connector on the back of the Cooling Module for the cell’s internal temperature
probe. Buffer temperature is also automatically monitored at the “FLOW OUT” port
(Figure 1C) of the Cooling Module by its own internal temperature sensor.
COOLING
MODULE
FLOW
IN
FLOW
OUT
FLOW
TUBING REDUCER
TEMPERATURE
PROBE
PUMP
CHAMBER
GEL
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