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nitrogen control system
  • Monitors and displays dew/frost point between -80 and +20 degrees C on LED readout
  • Features extreme sensitivity—measures moisture volumes from 0.5 PPM to 23,000 PPM
  • Mounts in dry boxes and other hermetically sealed enclosures for accurate in-place moisture monitoring and control
  • Interfaces with Terra's Dual Purge™ System for completely automatic nitrogen purging
  • Panel mountable for continuous monitoring of cleanrooms and other controlled areas
  • Takes the guesswork out of moisture control while saving on nitrogen consumption!
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  Cat. # Price
DewWatch™ Controller Unit
(Includes LCD meter, recorder output in mA or mV, one Form C alarm relay, sensor probe, 5-ft. cord and User's Manual)
1401-94 $ 5,951
nitrogen control system
DewWatch™: Humidity Monitor & Control
(Dual Purge™ System, RB® valve required)
No one has the time to attend to all of the factors involved in maintaining the desired humidity conditions inside an enclosed environment. Therefore, you need a nitrogen control system that will automatically regulate the gas purge to compensate for such operating variables as the size and condiion of the chamber, the frequency and duration of access, and changing ambient humidity levels.

The DewWatch™ meets these monitoring/control requirements—economically and reliably.

Maintains Consistent, Traceable Glove Box Environment—Automatically
The extreme sensitivity and precision of the DewWatch™ makes it suitable for your most demanding applications. It operates over the -80 to +20 degree C dew point range, which is equivalent to 0.5 PPMV to 23,000 PPMV in gases at 1 atmosphere.

In glove box applications, the DewWatch™ performs a dual function. The LED display provides a continuous readout of the dew/frost point inside the chamber in whichever scale range you order (see specifications below). More importantly, it operates with the Dual Purge™ System to precisely control the flow of nitrogen into the enclosure and maintain a preset dew point.

Simple, Reliable Operation
All you have to do is find out from your supplier or process engineer exactly what dew point you need to maintain, set the desired level , interface the unit with Terra's Dual Purge™ System and then let it do its job. The unit's quick response sensor, when properly installed inside the chamber, will deliver a quick readout of the internal dew point. The controller will allow the Dual Purge™ System to adjust the nitrogen flow to maintain this desired dew point within 2 degrees C (3 degrees C in the -80 to -65 degree C range) no matter how operating or ambient conditions may change.

Special Design Features for Versatile Applications
Each DewWatch™ unit is individually calibrated and consists of a control unit and a humidity sensor.

Standard Dew/Frost
Point Range:
-80°C to +20°C
120VAC, 50/60Hz
Operating Temp:
0°C to +55°C
Storage Temp.:
-20°C to +70°C
Warm-up Time:
3 min.
0 to 20mA, 4 to 20mA, 0 to 100mV, 0 to 2V
General purpose, panel mount, RF shielded
5.70" x 4.36" x 2.84"
(144.8mm x 110.7mm x 72.1mm)
1.65 lbs. (748 g)

Moisture Probe
Type: Aluminum Oxide Moisture Sensor Element
Calibrated Range: -80°C to +20°C
Pressure Rating: 5000 psig
Operating Temp. -110°C to +70°C
Storage Temp.: 70°C max.
Flow Rate: 10,000 cm/sec. linear velocity max. in gas phase.
Calibration Accuracy: ± 2°C in range of -65°C to +20°C, ± 3°C in range of -80°C to -65°C
Calibration Data: Calibration Data: On EPROM (Electrically Erasable Programmable Read-Only Memory)
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