948 "Auto-Test" Leak Detector

This Varian 948 series leak detector has been specifically designed for high productivity testing environments. This unit allows single button pass/fail test cycling and fully automatic spectrometer tuning and calibration. The Contra-Flow vacuum system arrangement in these machines uses a valve manifold that has been specially designed for fast cycle times and the maximum possible reliability.

In addition to the clear, front panel LED leak rate, pressure, and machine condition displays, information is also available on analog, parallel I/O, and RS-232 remote interfaces.

While the 948 leak detector provides high sensitivity for detecting small leaks, it can leak test to 10 atm-cc/sec. An atmospheric gross leak option allows searching for helium leaks with test port pressures as high as 760 Torr.

Features Benefits

  • Fully automatic operation and spectrometer tuning
  • One button Pass/Fail testing
  • Easily customized pumpdown and test cycles
  • Fully protected from the possibility of operator errors, air inrushes, and power failures
  • Protected from the possibility of operator errors, air inrushes, and power failures
  • Operator skill not requirement for spectrometer tuning, calibration, and zeroing
  • Specially-designed high conductance valve manifold
  • Reduces pumpdown times for faster test cycling
  • Proven reliability to over one million cycles
  • No additional utility requirements
  • Displays leaks from 10 to 2 x 10-10 atm cc/sec
  • Measures 10-10 range leaks without liquid N2
  • Optional atmospheric and non-helium gross leak capability
  • Large leaks can be detected before high vacuum
  • pumpdown, with or without presence of helium tracer
  • Parallel I/O and RS-232 remote interfaces available
  • Unit can be remotely controlled and provide complete real time testing data
  • Liquid Nitrogen Cold Trap
  • The cold trap enhances the cleanliness of the test port.
  • Diffusion-pumped version
  • Low cost with diffusion pump

Technical Specifications

Sensitivity:  2 x 10-10 atm cc/sec (helium),       4x1011 atm cc/sec (air)

Response Time:  Less than two seconds for helium, in accordance with AVS standard 2.1

Amplifier Drift:  Less than 2% of the full scale of the most sensitive range, in accordance with AVS standard 2.1

Noise Level:  Less than 2% of full scale, peak-to-peak, in accordance with AVS standard 2.1

Leak Indication:  A 50-segment bar graph indicator displays leak rates from 10 to 1 x 10-10 atm cc/sec automatically. The manual mode can also be used for any decade scale. A leak can also trigger an audible alarm whose frequency varies in proportion to the size of the leak.

Spectrometer Tube:  The preamplifier is computer optimized, temperature stabilized, and solid state. Programmed warm up minimizes start-up time. The tube is kept at a constant temperature at all times to maintain stability. The ion source has dual filaments of long-life, thoria-coated iridium.

Cycle Time:  Blanked port can be cycled to fine leak test in 6 seconds, and gross leak test in 3 seconds. The auto sequencer option provides clear accept/reject signals and allows programming the roughing, testing, and cycling times.

High Vacuum Pump:  90 l/s diffusion pump

Rough Pump:  7 cfm (11.9 m3/hr) direct-drive mechanical pump.

Fore Pump: 7 cfm (11.9 m3/hr) direct-drive mechanical pump

Automatic Valve Sequencing:  Microprocessor-controlled valve operation for automatic system cycling. The test and roughing valves are vacuum-actuated, requiring no air supply. Automatic shutdown Is achieved with one switch function.

Test Port:  1 1/8 inch (28 mm) ID quick coupling type

Power Requirements:  115 V and 230 V, 50/60 Hz, (30/15 amps)

Cabinet:  The front panel is removable to allow easy access to all components. Electronics are accessed from hinged turret door and removable back panel. Cabinet is caster-mounted for mobility.

Weight:  435 lb (198 kg) approx. net;   510 lb (232 kg) approx. shipping

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