CLO & CLOR – Capillary Leak Open


VTI’s CLO and CLOR calibrated gas leaks feature precision-crimped stainless steel capillaries that provide accurate flow-rate restriction for any gas. These “open-style” or “in-line” leaks do not have a reservoir of gas but, instead, use an external gas source. Under pressure, gas flows through the capillary restriction into the system or part being tested. This yields a precise, known flow rate based on the inlet and outlet pressures.

We can weld CLO and CLOR leaks into many different inlet and outlet attachment fittings. These capillary leaks can also be built into an actual or simulated test part that can then periodically be put through a regular test cycle to validate and calibrate the entire leak test system. This is the only way to be sure that the total test procedure is effective at locating leaks that could cause products to fail.

These open-style leaks can be calibrated at one inlet pressure (your test pressure) to obtain a single specified leak rate. Alternatively, they can be calibrated at several inlet pressures, usually three, to obtain different leak rates and the ability to vary the rate within a range (usually 10x) of values using the calibration curve of pressure vs. leak rate provided.

  • Stable: low temperature coefficient of 0.2% per degree Celsius
  • Versatile: appropriate for any gas at a wide variety of leak rates
  • Durable: made of all-welded stainless steel
  • Adaptable: easily integrated into a production test-part to simulate a defect with a specific leak rate
  • Bakeable: all-metal fittings suitable for ultra-high vacuum environments
  • Meets ISO requirements: NIST-traceable, A2LA-accredited Calibration Certification

Do you have any questions?