1. A rotation speed regulating mechanism for pneumatic tools, comprising:
an air intake member which includes a hollow element, an air outlet end extended axially from one end, an air inlet end extended axially from another end thereof, an air regulation port and an air inlet, the air outlet end and the air inlet end being not communicating with each other from distal ends thereof, the air regulation port and the air inlet being formed radially to communicate with the air inlet end and the air outlet end, the air intake member further having an external screw thread on the periphery thereof;
an airflow knob having an annular sleeve which has an internal screw thread to couple with the external screw thread of the air intake member to move the annular sleeve relative to the air intake member for adjusting covering range of the air regulation port and regulating airflow passing through the air regulation port to regulate rotation speed in a stepless fashion; and
a shell fixedly coupled on an outer side of the air intake member to encase the air intake member and the annular sleeve and form a gap between the shell and the air intake member to receive the airflow.
2. The rotation speed regulating mechanism of claim 1, wherein the internal screw thread and the external screw thread are a single thread.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus comprising:
a first sensor producing a first data signal characterizing a carbon dioxide concentration in the gas stream, the first sensor comprising a tunable diode laser absorption spectrometer comprising a laser light source that is modulated at a modulation frequency while being scanned over a wavelength range that includes a selected absorption transition for carbon dioxide and a detector that detects an intensity of light reaching the detector at a multiple of the modulation frequency after light from the laser light source passes through the gas stream, the first data signal comprising the intensity as a function of wavelength at the multiple of the modulation frequency; and
a master processor that receives the first data signal and measurements of pressure and temperature in the gas stream, the master processor performing operations comprising:
demodulating the intensity as a function of wavelength at the multiple of the modulation frequency received in the first data signal to remove a sloping baseline caused by the scanning of the laser light source over the wavelength range and to calculate the carbon dioxide concentration in the gas stream based on a signal strength of the demodulated intensity at the selected absorption transitions;
calculating a total nitrogen and inert species concentration in the gas stream as a remainder when the calculated carbon dioxide concentration and an inferred total hydrocarbon concentration are subtracted from 100%, the inferred total hydrocarbon concentration in the gas stream being based on a database of characteristic natural gas concentrations; and
implementing an algorithm that determines an energy content of the gas stream using as inputs the measured temperature, the measured pressure, the carbon dioxide concentration, and the calculated total nitrogen and inert species concentration.
2. An apparatus as in claim 1, further comprising one or more connections configured to attach to a fitting on a gas pipeline to divert the sample gas stream from the gas pipeline to the first sensor.
3. An apparatus as in claim 1, wherein the selected absorption transition for carbon dioxide is between approximately 2003 and 2004 nm.
4. An apparatus as in claim 1, further comprising one or more connections configured to attach to a fitting on a gas pipeline to divert the sample gas stream from the gas pipeline to the first sensor.
5. An apparatus as in claim 1, wherein the wavelength range is between approximately 1300 nm and 2100 nm.
6. An apparatus as in claim 1, wherein the detector comprises at least one of an indium gallium arsenide (InGaAs) photodiode, an indium arsenide photodiode, an indium antimonide detector, an indium arsenide (InAs) photodetector, a silicon (Si) photodetector, a germanium (Ge) photodiode, a mercury-cadmium-telluride (MCT) detector, and a lead-sulfide (PbS) detector.
7. A computer-implemented method comprising:
receiving a first data signal characterizing a carbon dioxide concentration in a gas stream, the first data signal comprising a light intensity as a function of wavelength at a multiple of a modulation frequency, the modulation frequency being imposed on a laser light source of a tunable diode laser absorption spectrometer as the laser light source is scanned over a wavelength range that includes a selected absorption transition for carbon dioxide;
demodulating the intensity as a function of wavelength at the multiple of the modulation frequency to remove a sloping baseline caused by the scanning of the laser light source over the wavelength range and to calculate the carbon dioxide concentration in the gas stream based on a signal strength of the demodulated intensity at the selected absorption transition;
receiving measurements of pressure and temperature in the gas stream;
calculating a total nitrogen and inert species concentration in the gas stream as a remainder when the calculated carbon dioxide concentration and an inferred total hydrocarbon concentration are subtracted from 100%, the inferred total hydrocarbon concentration in the gas stream being based on a database of characteristic natural gas concentrations; and
implementing an algorithm that determines an energy content of the gas stream using as inputs the received measurements of temperature and pressure, the calculated carbon dioxide concentration, and the calculated total nitrogen and inert species concentration.
8. A method as in claim 7, further comprising producing the first signal using the tunable diode laser absorption spectrometer.
9. A method as in claim 8, wherein the producing the first signal further comprises modulating the laser light source at the modulation frequency and detecting the light intensity as the function of wavelength at the multiple of a modulation frequency using a detector.
10. A method as in claim 7, wherein the selected absorption transition for carbon dioxide is between approximately 2003 and 2004 nm.
11. A method as in claim 7, wherein the wavelength range is between approximately 1300 nm and 2100 nm.
12. A method as in claim 7, wherein the light intensity is measured by a detector of the first sensor, the detector comprising at least one of an indium gallium arsenide (InGaAs) photodiode, an indium arsenide photodiode, an indium antimonide detector, an indium arsenide (InAs) photodetector, a silicon (Si) photodetector, a germanium (Ge) photodiode, a mercury-cadmium-telluride (MCI) detector, and a lead-sulfide (PbS) detector.
13. A computer program product comprising a non-transitory machine-readable medium storing instructions that, when executed by at least one programmable processor, cause the at least one programmable processor to perform operations comprising:
receiving a first data signal characterizing a carbon dioxide concentration in a gas stream, the first data signal comprising a light intensity as a function of wavelength at a multiple of a modulation frequency, the modulation frequency being imposed on a laser light source of a tunable diode laser absorption spectrometer as the laser light source is scanned over a wavelength range that includes a selected absorption transition for carbon dioxide;
demodulating the intensity as a function of wavelength at the multiple of the modulation frequency to remove a sloping baseline caused by the scanning of the laser light source over the wavelength range and to calculate the carbon dioxide concentration in the gas stream based on a signal strength of the demodulated intensity at the selected absorption transition;
receiving measurements of pressure and temperature in the gas stream;
calculating a total nitrogen and inert species concentration in the gas stream as a remainder when the calculated carbon dioxide concentration and an inferred total hydrocarbon concentration are subtracted from 100%, the inferred total hydrocarbon concentration in the gas stream being based on a database of characteristic natural gas concentrations; and
implementing an algorithm that determines an energy content of the gas stream using as inputs the received measurements of temperature and pressure, the calculated carbon dioxide concentration, and the calculated total nitrogen and inert species concentration.
14. A computer program product as in claim 13, further comprising producing the first signal using the tunable diode laser absorption spectrometer.
15. A computer program product as in claim 14, wherein the producing the first signal further comprises modulating the laser light source at the modulation frequency and detecting the light intensity as the function of wavelength at the multiple of a modulation frequency using a detector.
16. A computer program product as in claim 13, wherein the wavelength range is between approximately 1300 nm and 2100 nm.
17. A computer program product as in claim 13, wherein the light intensity is measured by a detector of the first sensor, the detector comprising at least one of an indium gallium arsenide (InGaAs) photodiode, an indium arsenide photodiode, an indium antimonide detector, an indium arsenide (InAs) photodetector, a silicon (Si) photodetector, a germanium (Ge) photodiode, a mercury-cadmium-telluride (MCT) detector, and a lead-sulfide (PbS) detector.