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Description and Principle of Operation
APPLICATION
The Universal Analyzers Model 1095E Acid Aerosol "Freezer Chiller" is a system on a 21" x 27" plate designed to
achieve an exit dew point of -25°C. It is designed to remove moisture to a level of 650 PPM. This reduces the chances
of low levels of acid formation therefore protecting downstream components as well as minimizing losses of measured
components.
The use of a heated filter and a heated sample line are required to be installed between the sample extraction location
and the input of the 1095E sample cooler. The temperature of the sample must be kept above the boiling point of water
and above the dew point of any chemical reactions that would skew the desired analytical results.
DESCRIPTION
The Universal Analyzers Model 1095E Acid Aerosol "Freezer Chiller" contains a combination of Kynar and Glass/Kynar
impinger type heat exchangers. These are mounted within heat transfer blocks, which are cooled by thermoelectric
elements utilizing the "Peltier Effect". The condensate is removed in multiple stages, one at the temperature of the
ambient air surrounding the Freezer Chiller by flowing through the impinger referred to as the Passive Channel, then
by passing the sample into a heat exchanger cooled to 4°C by the thermoelectric elements referred to as the Active
Channel. The sample gas is then further cooled by special cascaded Peltier elements to negative 25°C freezer alternating
Impingers controlled by a PLC. The 4°C Active Channel is also referred to as Channel 1 and the two freezer Channels are
referred to as Channel 2 and Channel 3.
In standard operation Channel 1 will always hold at 4°C within a band 1°C. Channel 2 and Channel 3 cycle their operation.
The normal cycle operations (no alarms) are as follows:
Channel 2 Pre-Chill and Channel 3 Off - This cycle is the initial status upon startup. The switching valve selects Channel 2
and Channel 2 has power applied to the cooling elements until it has reached -10°C or the Pre-Chill time has elapsed.
Channel 2 Dwell and Channel 3 Off - This Cycle is the main cycle for the cooling elements on Channel 2 to chill and
for sample to run through Channel 2. It will need to be adjusted to be long enough for Channel 3 to properly defrost but
shorter than the time for ice to build up in the outlet of Channel 2, causing the flowswitch to trigger a 'Frozen Column'
alarm.
Channel 2 Dwell and Channel 3 Pre-Chill - During this cycle Channel 2 Dwell Time completes, Channel 2 continues to
cool, and sample continues to run through Channel 2. Channel 3 is triggered to cool for up to 30 minutes. If Channel 3
reaches negative 10°C before 30 minutes has elapsed this cycle will complete and move to the following cycle.
Channel 2 Off and Channel 3 Dwell - This Cycle is the main cycle for the cooling elements on Channel 3 to chill and
for sample to run through Channel 3. It will need to be adjusted to be long enough for Channel 2 to properly defrost but
shorter than the time for ice to build up in the outlet of Channel 3, causing the flowswitch to trigger a 'Frozen Column'
alarm.
Channel 2 Pre-Chill and Channel 3 Dwell - During this cycle Channel 3 Dwell Time completes, Channel 3 continues to
cool, and sample continues to run through Channel 3. Channel 2 is triggered to cool for up to 30 minutes. If Channel 2
reaches negative 10°C before 30 minutes has elapsed this cycle will complete and move to the following cycle.
A Moisture sensor is provided to sense the presence of condensate, should any exist in the tubing following the chiller.
This WCSF (Water Carry-Over Sensor with Filter) includes a visible steel fiber filter. This WCSF allows the operator
to inspect the condition of the heated stack filter. The integral moisture sensor with the sensing elements is located in
the bottom of the filter bowl to provide an early warning if liquid carries over past the freezer chiller. If water carry-over
is sensed, the Alarm Message "Water Carry-Over" is displayed. With Channel 1 Chiller high temperature (>10°C) the
Operator Interface displays "Ch1 High Temp". Either of these stops the Sample Pump.
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MAN.1095E.REVB.12232014
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