Universal Analyzers 500 series User Manual page 9

Description and Principle of Operation
DESCRIPTION
The Universal Analyzers 500 Series Thermoelectric Gas Coolers condition gas sample streams to remove water vapor. The
gas sample is cooled thermoelectrically to a controlled temperature, and water vapor is condensed and removed.
The key to success is being able to condense the water from a wet gas sample with a minimal loss of the water soluble gas
fraction. The separation occurs in a classical impinger, which has a highly polished cylindrical surface, cooled to the desired
dew point temperature. The gas sample is brought to the bottom of the cylinder through an insulated tube and allowed to
rise through a narrow annular area at a relatively high Reynolds number to insure the entire sample is influenced by the cold
surface. The condensate falls down the cold, polished surface in the form of a sheet (as opposed to droplets or the bubbling
of the gas sample through the condensate) which minimizes the surface area in contact with the gas sample.
The temperature of the cylindrical, condensation surface of the heat exchangers is maintained through intimate contact with
aluminum heat transfer blocks. The blocks are cooled with thermoelectric elements, controlled to a temperature of 5°C. The
temperature sensor is a type "K" thermocouple. The temperature controller is proportional with a band of 1°C.
The fan cooled heat sink is constructed from anodized, pure aluminum fins which transfer heat to the surrounding air. The
pure aluminum material is a far better conductor of heat than the aluminum alloys which are normally used for extruded heat
sinks. The result is an assembly with superior heat exhausting capabilities under high ambient temperature conditions.
The 500 Series Coolers have a digital display for front panel indication of the operating temperature of each of the heat
transfer blocks (switch selectable) in degrees Centigrade. Two internal jumpers at the top of the control circuit board within
the enclosure can be moved to change the indicated temperature to read out in degrees Fahrenheit.
Three LED lamps to indicate the status of the cooler. The "COOL" lamp is a green LED which indicates when the operating
temperature has fallen below the factory set temperature of 10°C. An "Over-temperature relay" is energized and closed to
the cool position when the "COOL" lamp is on. The relay board within the enclosure has dual terminal strip relay contacts for
alarm/shutdown purposes. The external gas sample pump may be interlocked with this relay to power off when temperatures
become too high (fail safe).
The "DRY" lamp is a green LED which indicates when there is no water in contact with the water carry-over sensor (provided
separately or as a system option). If no moisture sensor is used, the lamp may be turned off by installing a jumper on the
moisture sensor input terminals on the relay board. Without a moisture sensor installed, the "DRY" lamp is always lit and
doe not indicate a condition. The moisture sensor relay, which is energized in the "DRY" condition, provides contacts to an
annunciator panel and/or to turn off the sample pump in the "wet" condition.
The "TC" lamp is a red LED which indicates when there is a problem (open connection) in the temperature control
thermocouple. The "Over-temperature" relay will also transfer to the high temperature condition if the red "TC" lamp
comes on.
The WCO or WCOF, optionally available with the 500 Series Cooler Systems, is a sensor which detects the presence of
liquid water. One should be placed in each gas sample stream directly after the cooler to provide an alarm if condensate is
detected. The electronics associated with water carry-over sensors are included as a standard part of all Universal Analyzers
Thermoelectric Sample Coolers. Dual relay contact sets are provided for each moisture sensor. Relay contacts are energized
and closed to the dry position when the WCO sensor is dry and the unit is powered on.
LED INDICATOR CHART
LED Color Status
On
COOL Green
Off
On
DRY
Green
Off
On
TC Red
Off
Condition
Operating properly, temperature below 10°C
Temperature too high or unit is OFF
WCO sensor connected and sample is dry
Moisture detected or jumper installed
Temperature control TC has BAD quality
Temperature control TC has OK quality
Over Temperature: Energized, towards COLD
Over Temperature: De-Energized, towards HOT
Moisture Sensor: Energized, towards DRY
Moisture Sensor: De-Energized, towards WET
Over temperature: De-Energized, towards HOT
Page 9 of 44
Relay Status
Does not affect relays
MAN.500.REVD.06302015