Apparatus and method for measuring gas concentrations
AssigneeVaisala Oy
InventorAri Lehto
Life of this patent
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Abstract
An apparatus and method measures the concentration of a gas. The apparatus comprises a radiation source (70) for emitting radiation onto the gas (79) to be measured, whereby the radiation source (70) is comprised of an anode (4) and a cathode (9), and as an emitting fill gas the same as the gas (79) to be measured; and a radiation detector (74) with which the radiation transmitted through the gas (79) to be measured can be detected. The cathode (9) functions as an electron emitter, and between the anode (4) and the cathode is connected such a low operating voltage that does not cause ionization or essential dissociation of the emitting gas. The design provides an approximate temperature tracking of the radiation source with the ambient temperature.
Claims20
An apparatus for measuring the concentration of a gas, said apparatus comprising:
- a radiation source for emitting radiation on the gas to be measured, said radiation source further being comprised of
- an anode and a cathode, the cathode operates as an electron emitter, and
- an emitting fill gas the same as the gas to be measured, and
- a radiation detector capable of detecting the radiation transmitted through said gas to be measured, and
- between said anode and said cathode is connected such a low operating voltage at which minimal ionization or dissociation of the emitting fill gas occurs.
The apparatus as defined in any foregoing claim, wherein an operating voltage of less than 5 V is connected between said anode and said cathode.
A method for measuring concentration of a gas, the method comprising the steps of:
- emitting radiation onto the gas to be measured;
- detecting transmitted radiation;
- generating said emitted radiation by nonionizingly exciting an emitting gas which is the same as the gas to be measured by low-voltage-accelerated emission of electrons such that minimal ionization or dissociation of the emitting gas occurs.
Dependencies are inferred from the claim text.