Helium Leak Detectors

Thermionics offers helium leak detectors for industrial quality control tests. Originally designed to find leaks in aircraft fuel tanks, our leak detectors are a very effective tool for pinpointing leaks in any pressurized vessel.

The HLD-3000, is a portable unit with digital electronics and display including 50 feet of sniffing hose with an LED handle.  The LED handle has intrinsically safe electrical barriers for use in potentially hazardous areas such as fuel tanks and paint rooms.  The LED display on the handle indicates up to four levels of leak rates and one alarm set point.  Standard or custom probes are available for different applications.



  • Quartz membrane detection
  • Automatic zero of helium background
  • Intrinsically safe probes
  • LED leak rate at the probe
  • 50 foot sniffing hose
  • Variety of probes available
  • Transparent protective shield

Performance Specifications

  • Basic Detector
  • 1.0 x 10-7 mbar/liter/sec sensitivity
  • 1.0 sec response time
  • Detector with 50 ft. sniffing hose
  • 1.0 x 10-7 mbar/liter/sec sensitivity
  • 1.5 sec response time
  • Scan rate: 0 to 6 inches per second

The HLD-3000 uses an evacuated gas cell covered by a quartz membrane to detect escaping helium gas from containers filled to a positive pressure of an air-He gas mixture.  The detector features automatic internal calibration using an external standard leak for reliable performance and ease of use.

  • Protec P3000 Wise Technology Helium Leak Detector Module by Inficon
  • Zero background switch located on the probe handle
  • Standby switch on the handle rest eliminates the intake of background helium into the sniffing probe
  • Quick connect/disconnects for sniffing hose and LED conductor wiring
  • Flat paddle probe assembly, 4 x 6 in., quick connect/disconnect capable, stainless steel filter
  • Flex probe with flair tip, 3 in. long, quick connect/disconnect capable, stainless steel filter
  • All stainless steel cart-enclosure with powered ventilation and internal retractable 50 foot power cord
  • Portable unit includes swivel casters with locks and hanger for 50 foot sniffing hose and probe handle
  • Integrated tool box
  • Dimensions: 30 in. long, 18 in. wide, 50 in. high
  • Power requirements: 120 VAC/20 A
  • Shipping crate: 49 in. x 32 in. x 58 in., 400 lbs


Airplane Fuel Tanks

The HLD-3000 has replaced the former “soap bubble test” as a quality measurement method of fuel tanks by certain airplane manufacturers. The Helium technique is 100 times more sensitive as a leak detection method than the soap bubble test. The increased leak detection sensitivity and ease of use has saved these companies literally hundreds of thousands of dollars on the manufacturing line.

Pressurized Tanks

The HLD-3000 offers a fast, accurate and clean method of identifying minute leaks in pressurized tanks. The HLD-3000 can be calibrated for various leak levels to match your particular quality standard. The HLD-3000 is rugged enough to be used outdoors as well as indoors.

Many custom probes and accessories are available for our helium detectors.

Custom Probes and Accessories

Sniffer Hose and Handle

  • 50-foot hose standard, other lengths available
  • Handle extends 2–4 feet
  • LED leak-rate indicator on handle
  • Quick-disconnect for easy interchange of customized probes

Sniffer Probes

  • Attaches to sniffer hose handle
  • Fully customizable to meet your specific requirements
  • Standard models including: small flex tip probe, large paddle probe

  • Small Flex Tip Probe
  • 12″ flex wand
  • 1-1/2″ tip
  • Easily attaches to sniffer hose

  • Large Paddle Probe
  • 4″ x 6″ surface
  • Easily attaches to sniffer hose


  • Stainless steel
  • Holds probes and calibrated leak
  • 7.75″ H x 15.75″ W x 8″ D

Sniffer-Design Helium Calibrated Leak

  • Stainless steel tubes
  • Used to check your detector system