The TPS model calibrated helium leak standard works equally well calibrating helium leak detectors that test under vacuum, and with helium leak detectors that sample from atmosphere utilizing a sniffer probe. This is enabled by the design, which features both an integral KF25 (NW25) vacuum fitting and a pin-point helium source that accepts and aligns most manufacturers sniffer probes with virtually no dead volume where helium can accumulate and cause inconsistent readings. Calibrated helium leak standards with shut-off valves and should not be used to calibrate a “Sniffer Type” leak detector. The FEP permeation type leak element is not driven by differential pressure but helium partial pressure flows helium at virtually the same rate flowing into a vacuum or flowing into normal atmospheric conditions.
This model is available with various sizes of DOT rated gas reservoirs; the reservoir size is usually dictated by the leak rate to insure an acceptable yearly depletion rate.
We use the finest grade of FEP available to manufacture the FEP leak elements. They have been tested at temperatures ranging from 10°C to 40°C, yielding a temperature coefficient of approximately 2.5%/°C with no anomalous behavior.