Manufacturer : Agilent
Model : G1322A
Manufacturer : Agilent
Model : G1322A
Made in : Japan
Weight lbs : 12
The Agilent 1200 Series vacuum degasser, model G1322A, comprises a 4-channel vacuum container, including 4 tubular plastic membranes, and a vacuum pump. When the vacuum degasser is switched on, the control circuit turns on the vacuum pump which generates a partial vacuum in the vacuum container.
The pressure is meassured by a pressure sensor. The vacuum degasser maintains the partial vacuum by turning on and off the vacuum pump depending on the signal from the pressure sensor.
The LC pump draws the solvents from their bottles through the special tubular plastic membranes of the vacuum container. As the solvents pass through the vacuum tubes any dissolved gas in the solvents permeates through the membranes into the vacuum container. The solvents will be almost completely degassed when leaving the outlets of the vacuum degasser.
The vacuum degasser has two different normal operation modes and a continuous mode. In operation mode 1 the vacuum degasser works around a defined set point (115 Torr). Due to environmental conditions it is possible that the vacuum degasser cannot reach the pre-defined set point.
Under this condition the operation mode 2 becomes active and the vacuum pump is activated in defined time intervals (vacuum level 115 to 190 Torr). In case of a malfunction of the vacuum degasser (vacuum level above 190 Torr) the instrument is turned into the error mode.
The amplifier and comparator circuit determines the working range of the vacuum that has to be built up. When the vacuum degasser is turned on and the vacuum in the chamber is not within working range (above error limit of 190 Torr), the amplifier and comparator circuit sends a signal to the vacuum pump driver and the timers of the vacuum pump (timer 1) and the solenoid
valve (timer 2).
The vacuum pump is turned on immediately while the solenoid valve closing is delayed by 15 seconds. This time delay allows the vacuum pump to start without load before it is connected to the vacuum chamber. The status indicator turns yellow when the pump is activated. The status lamp is turned off as soon as the vacuum is below the error limit.
When the vacuum in the chamber reaches its operation mode 1 (approximately 115 Torr) the amplifier and comparator circuit turns off the solenoid valve and the vacuum pump is turned off by a timer with a delay of 15 seconds.
As soon as the pressure sensor detects that the limit of the operation mode 1 has been exceeded (e.g. when dissolved gas from the solvent diffused into the vacuum chamber) the vacuum pump is started again as described before. The pressure signal is available at the auxiliary output. It allows to monitor the vacuum system. The upper limit of operation mode 1 is 600 mV. Values below 600 mV on the pressure output indicate sufficient vacuum in the chamber. If the 600 mV are exceeded the vacuum pump will be started to keep the vacuum with in its working limit.
The amplifier and comparator circuit also activates the timer 3 when the vacuum in the vacuum chambers is below operation mode 1. The timer 3 is reset when operation mode 1 is reached within a maximum of 8 minutes.
If operation mode 1 is not reached and the time (8 minutes) of timer 3 elapsed, the timer mode (operation mode 2) is activated. In this mode the vacuum pump is automatically turned on every 2 minutes for a time frame of 30 seconds.
Timers 1 and 2 are activated as described earlier. The error monitor continuously checks the error limit of the degasser (190 Torr). If the error limit is exceeded , the error timer is activated and the yellow status indicator lamp is turned on. The vacuum pump is turned on continuously.
If the vacuum pump cannot reach either of its two operation modes within 8 minutes (error timer limit) the error driver is activated. The error driver will deactivate the vacuum pump and solenoid valve. The status lamp turns red and the error output on the remote connector will be activated.