Table 4 - SPI Baud Rate Adjustment
BAUD Rate
DIP Switch #6
DIP Switch #7
1200
ON
ON
2400
Off
ON
4800
ON
Off
9600
Off
Off
Operation
The temperature control unit cycles a heater and cooling valve
to maintain precise temperature control of the To Process water
temperature. Your unit may differ somewhat depending upon
the various options purchased; however, the overall function of
the unit is fundamental to all our temperature control units.
The pump continuously pumps water from the mixing tube
through the heater tube and out to the process equipment. The
water is pumped through the process equipment at a high flow
rate to ensure turbulent flow and efficient heat transfer. Once the
water exits the process equipment it returns to the mixing tube.
A thermocouple is mounted at the exit of the heater tube to
measure the temperature of the To Process water temperature.
This temperature is used by the microprocessor to determine if
temperature adjustment is required. If the water temperature is
below set point, the heater is energized. Conversely, the cooling
solenoid or modulating valve is opened whenever the water
temperature is above set point. Opening the cooling solenoid or
modulating valve allows some of the warm water from the
process water circuit to exit through the cooling water out line.
At the same time, cool water is injected into the process circuit
from the cooling water in line. The replacement of warm water
with cool water provides the cooling that is required. The
cooling valve is cycled by the microprocessor to allow precisely
controlled amounts of cooling water to enter the system.
A bypass line is provided to protect the pump from overloading
during those times with the process water circuit is shut off. This
prevents the pump from a deadheading situation and ensures
flow through the pump to keep the pump seal from overheating.
A pressure switch is provided to ensure that there is sufficient
inlet cooling water pressure to allow the unit to operate without
the possibility of steam flashing. A pressure relief valve is provid-
ed to vent the process loop if the operating pressure becomes
too high.
WARNING: Do not plug the opening in the pressure relief
valve under any circumstances as this is safety device that
must not be defeated.
A small pump seal flush line is provided to continuously flush
the pump seal of dirt and debris.
Construction
Pump Assembly
The centrifugal close-coupled pump features a specially
designed cast volute to eliminate fittings and provide easy
connection to the heater and/or mixing tubes. The pump volute
is constructed of cast iron. The ¾ through 2 HP pumps have
stainless steel impellers and pump shafts. The 3 HP through 7½
HP pumps have an iron impeller with a bronze wear ring in the
pump volute and carbon steel shafts with a bronze sleeve
covering. All pump sizes use a carbon Ni-Resist mechanical
pump seal. All pumps include a pump seal flush line.
Heater and Mixing Tube
Depending on the options and heater KW capacity of the unit,
there will be either two heater tubes or a heater tube and a
mixing tube. Both the heater and mixing tubes have been
designed to match up to the pump volute casting. The tubes are
constructed of cast iron and are designed to connect with the
pump volute with two flange seals. Units with 0 KW through 12
KW heating capacity will include a larger heater tube and a
smaller mixing tube. Units with heating capacities of 18 KW or
24 KW will have two larger heater tubes and no mixing tube.
Heater
(not available on RB and RBD units)
The heaters are vertical flange mounted with Incoloy heater
element sheathing. All units will use one or more 9 KW or 12 KW
heater elements. The heaters are energized whenever the
microprocessor determines that heating is required.
Cooling Solenoid or Modulating Valve
The cooling solenoid or modulating valve meters the cooling
water required for proper cooling. The valve allows warm water
to leave the process loop while letting cooling water to enter the
loop. This valve is also used to vent the process circuit during
Vent and/or Purge sequences.
Pressure Switch
All units are equipped with a pressure switch to ensure
that the unit will not start until the inlet cooling water pressure
exceeds the pressure switch setting. This safety protects the
heater and pump seal from potential damage caused by
lack of water as well as ensuring that the system pressure
is above the vapor pressure of the water to prevent the
water from flashing to steam.
WARNING: If the Set Point temperature is 200°F (93°C) or
higher, the pressure switch should be set for a minimum of
25 PSI (1.75 Bar).
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An ISO 9001:2008 Registered Quality Company
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