Gas injection device
A gas injection device, wherein comprising: a gas channel including an air inlet provided at a upper portion therein and a gas outlet provided at a lower portion therein; and a light channel including an incident light channel and a reflected light channel provided at each side of the gas channel separately, wherein gases arrives at a surface of a sample to be tested via said gas channel and flows out from a slit between said light channel, the gas outlet of gas channel, and the surface of the sample to be tested, and gases flow in a manner of laminar flow with the Peclet number of an air flow being larger than 1. The gas injection device can effectively prevent air from returning back to the measurement system.
1. A gas injection device, wherein comprising:
a gas channel including an air inlet provided at an upper portion therein and a gas outlet provided at a lower portion therein; and
a light channel including an incident light channel and a reflected light channel provided at each side of the gas channel separately,
wherein gases arrives at a surface of a sample to be tested via said gas channel and flows out from said light channel and a slit between the gas outlet of said gas channel and a surface of the sample to be tested, and gases flow in a manner of laminar flow with the Peclet number of an air flow being larger than 1.
2. The gas injection device according to claim 1 wherein,
an inner diameter of the gas outlet of the gas channel, an inner diameter of said light channel, and a height from said gas channel to the surface of said sample to be tested meet the next formula:
Fd /π( d 2 /2+ Dh )μ<200,
wherein, F is a volume of gas flow; d is an inner diameter of the light channel; D is an inner diameter of the gas outlet of the gas channel, h is a height from the gas outlet of said gas channel to the surface of said sample to be tested, and μ is dynamic viscosity.
3. The gas injection device according to claim 1 wherein,
an inner diameter of said gas outlet is greater than that of said air inlet.
4. The gas injection device according to claim 1 wherein,
an inner diameter for the gas outlet of said gas channel is 0.1-250 mm.
5. The gas injection device according to claim 1 wherein,
an inner diameter of said light channel is 0.5-20 mm.
6. The gas injection device according to claim 1 , wherein,
a height from the gas outlet of said gas channel to the surface of said sample to be tested is 0.1-10 mm.
7. The gas injection device according to claim 1 , wherein,
a length of said gas channel is 0.1-10 cm.
8. The gas injection device according to claim 1 , wherein,
an inner diameter for the air inlet of said air channel is 0.1-20 mm.
9. The gas injection device according to claim 1 wherein,
a diameter for the surface where the gas outlet of the gas channel being formed is 1-300 mm.