Convectron Ionization Gauge Controllers

Granville - Phillips Model 275 for accurate low vacuum measurement

Series 275 Convectron gauges provide useful pressure measurement over 6 decades from 1 millitorr to 1000 Torr, or from 1 x 10^-3 mbar to 1000 mbar. This innovation in the art of vacuum measurement is accomplished with a single gauge tube and controller. The gauge tube contains a temperature compensated heat loss sensor which utilizes conduction cooling to sense pressure at lower pressures. At higher pressures, it utilizes convection cooling in which gas molecules are circulated through the gauge tube by gravitational force.

Their wide useful range, highly predictable performance and low prices make Convectron gauges an excellent replacement for conventional thermocouple and Pirani gauges. They also are the measurement systems to consider in applications where conventional thermocouple and Pirani gauges have not been suitable because of limited range, or drift, or slow response.

Convectron gauges may be considered for use in certain applications where more expensive gauges such as capacitance manometers would be the first choice were it not for their higher cost.

Convenience and Versatility

The Convectron gauge is designed to give "plug-in-and-read" convenience. No pre-installation calibration is required because it is computer calibrated prior to shipment. It snaps into an instrument panel cutout without tools or hardware.

Convectron gauges offer the following advantages relative to thermocouple gauges:

• System performance can be monitored continuously from atmosphere down without pressure blind spots.
• Purchase of additional controller and gauge tube models is not necessary if your needs change to different segments of the range.
• A much wider range can be covered with one Convectron gauge than with thermocouple gauges.
• There is no chance of error that might be caused by using the wrong gauge tube-controller combination. One gauge tube fits all controller models.

Due to their wide pressure range, convectron gauges can replace both thermocouple and Pirani gauges.

Accuracy

The accuracy of Convectron gauges is exceptionally good. Close attention has been given in the design to minimize those factors which produce errors in conventional heat loss transducers.

High Repeatability

Repeatability of Convectron gauges is excellent. For example, in typical tests at constant temperature, Convectron gauges were repeatable to 1/10 millitorr at 1 millitorr (1 x 10^-4 mbar at 1 x 10^-3 mbar) as measured by a precision digital capacitance manometer.

Fast Response time

The sensor in a Convectron gauge tube operates in an electronic feedback loop which keeps its temperature nearly constant. Thus response time is very fast because components do not have to change temperature significantly as pressure changes.

Fig.1 - Comparison of the range of a single convectron gauge with the range of typical thermocouple and Pirani gauges.

Series 275 Gauge Specifications

Useful Measuring Range

1 millitorr to 1000 Torr, or 1 x 10^-3 mbar to 1000 mbar, for N₂ using a single gauge tube and controller.

Ambient Operating Temperature Range: +4 to + 50 degrees C.

Tube Environmental Temperature Compensation Range:

+15 to +50 degrees C. Maximum tube temperature is 150 degrees C non-operating.

Recorder Output

0 to 9 volts non-linear, monotonically increasing pressure related signal is available on rear connector on all units.

Digital Readout

Four decade range indicated by lighted LED's, automatic ranging displays correct measuring units at all times.

Ranges

Torr                  mbar
0-995 millitorr       0-996 x 10-3 mbar
1.00-9.95 Torr        1.00-9.94 mbar
10.0-95.0 Torr        10.0-96.0 mbar
100-999 Torr          100-999 mbar

Readout Resolution of Digital controllers

Readout resolution ranges from 1 millitorr, or 1 x 10^-3 millibar, increments in the low pressure readings to 10 Torr, or millibar, at or near atmospheric pressure. Readability resolution is between 0.1% and 1% of full scale over most of the pressure range. For example, in the range from 48 to 190 millitorr, the digital controller has a readout resolution of 2 millitorr or less. The readouts are 48, 50, 51, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 64, etc. Complete readability data is included in the operating manual.

Scale Length of Analog Meter

7 inch (178 mm)

Power

105 to 125 VAC, 60 Hz, 10 W. On-Off Switch not provided.

Cable Assembly

6 ft., 3 wire, grounding power cord and 10 ft. shielded gauge tube cable prewired to controller connector.

Gauge Tube Mounting

Gauge tube axis must be horizontal to provide accurate measurement above about 1 Torr (1 mbar). Excessive vibration can slightly affect readout of digital gauge above about 1 Torr (1 mbar) because of forced convection effects in the tube.

Gauge Tube

Internal Volume: 40 cc (2.5 cu. in.)

Sensor: Gold plated tungsten.

Stability with Voltage Variation

Pressure reading changes by less than 0.02% of reading per 1% change in line voltage over most of the pressure range.

Bench Mounting

Controller is housed in attractive 1/4 DIN high impact plastic enclosure with no exposed electrical parts.

Rack Mounting

Controller snaps in or out of 3.625 in. (92 mm) square hole. No tools or additional hardware required.

Gauge Weights

       lbs.      kg
Net    3.5      1.6

Controller Dimensions

                             in.     mm
Front of panel, h., w.      3.81     97
Front of panel, depth        0.75    19
Rear of panel, depth
       with connector        8.65   220
Mounting hole, square        3.63    92

UOM=EA
Part No.	Description	est wt.	Quantity In Stock	Price	Quantity to order
IGC375	Digital Convectron Gauge System(includes 1 #275071 tube and 1 #37501210 10ft cable)	10	2	$990.00
275071	1/8in NPT Convectron Gauge Tube (HP #0960-0540)	0.25	5	$185.00
275196	NW25 Convectron Tube	0.25	0(#)	$205.00
275117	10ft Cable, Power Cord included	2	0(#)	$105.00
275075	25ft Cable, Power Cord included	2	0(#)	$134.00
275076	50ft Cable, Power Cord included	2	0(#)	$210.00
(#) Standard lead-time for out-of-stock items is approximately two weeks.
Ordering information. International (non-US) prices available through your local dealer.

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