Table of Contents
Advertisement
Description and Principle of Operation
A Vacuum switch is provided to monitor and alarm high inlet vacuum. The message "System Vacuum" will appear on the
top system status line of the operator interface, if there is high inlet vacuum.
A Flow switch alarms on low flow. The message "Low Sys Flow" will appear on the top system status line of the operator
interface, if there is low flow.
The heated head sample pump (oil-less diaphragm pump) is placed in the sample line between the 4°C and minus 30°C
heat exchangers. The first chilled heat exchanger takes enough of the water vapor from the sample to protect the pump.
The freezer heat exchangers are under a slight pressure because they are on the discharge side of the pump. This will
cause the dew point of the sample to be at its minimum. The pump has a sample pressure controller that is set at 10 PSI.
A Teflon Solenoid is used to alternate the online negative 25°C column and the offline channel that is in defrost mode.
The active freezer column flow impedance is monitored by a Flow switch to sense column freeze-up. If a flow restriction
is sensed before Online Dwell time out, the Alarm Message "Column Frozen" is displayed and after a time delay of 60
seconds the PLC will sequence to the other Freezer Column.
The offline column is pre-chilled to approximately negative 10°C before the column is brought online. Once the pre-chill
column is below negative 10°C, the program automatically advances to that column or after 30 minutes of pre-chill time
the pre-chill channel goes online. If the column fails to cool for 15 minutes once it is online, the message "Ch2 or Ch3
Malfunction" will be displayed.
The standard drain is a peristaltic pump is a positive displacement pump that allows for use in either a pressure or
vacuum sample. It provides for easy leak detection but does require periodic maintenance in replacement of the tubing.
A preventative maintenance program replacing the tubing every 6 months is a good practice.
To assist with the flow control a 5 Liter per minute flowmeter with needle valve is provided. Many analyzers require
between 1/2 Liter and 1 Liter per minute. Any extra flow can be sent into a bypass to increase the total flow which in turn
increases the response time of the system.
OPERATOR INTERFACE
The Model 1095E SO
is manually controlled through the Operator Interface located on the front of the unit, or remotely by
3
the I/O inputs to the PLC. The Interface is used to display and manually operate the 1095E Chiller.
MAIN DISPLAY
Line
1
Alarms Displayed and Channel 1 temperature
2
Channel 2, Status "DWELL" "OFF" "CHILL" and temperature
3
Channel 3, Status "DWELL" "OFF" "CHILL" and temperature
Note"*" Indicates the active column
4
Minutes remaining on Active Step
SYSTEM DEFAULTS:
The PLC will have following default values:
Dwell
180 Minutes - Length of time freezer Column is online
Pre-Chill 30 Minutes - Pre-Chill on the Offline Column, prepares the Column to become active.
Page 7 of 25
MAN.1095E.REVB.12232014
Advertisement
Table of Contents
