Partial pressure measurement probe for determination of gas concentrations e.g. oxygen and hydrogen in gas mixtures or solutions, has a gas-permeable, liquid-tight plastics membrane supported on a porous carrier

摘要

Probe for measurement of partial pressure has a body (6) with a permeable wall comprising a porous carrier (4) coated on its inner surface with a liquid-tight, gas-permeable plastics membrane layer (3). The carrier material is selected to have a porosity of 10-80% and a pore size of 1-300 micron, and is preferably inorganic e.g. metal, glass or ceramic in the form of a mesh or sinter. Porosity can be controlled by sintering with e.g. PTFE powder. Typically the carrier is 1-20 mm thick. The permeable membrane is preferably electrostatically sprayed and fused to the carrier, to a thickness of 20-1000 micron. Suitable materials are polyfluoroethylene (PTFE), tetrafluoroethylene- hexafluoropropylene copolymer (FEP), polyetherether ketone (PEEK), and polyamide. To measure partial pressure a carrier gas e.g. nitrogen, is fed via a mass-flow controller (22) to the probe inlet (12) and the permeate plus carrier gas from outlet (13) are led to an electrochemical sensor (12) calibrated for the permeate species. Independent claims are included for (1) apparatus utilizing the probe; (2) process for manufacturing the probe; (3) process for measuring partial pressure; (4) a computer program used in conjunction with the measurement process.