Gas turbine meter

A gas turbine meter for measuring the volume of a stream of gas flowing therethrough comprising:

• (a) An elongated, cylindrical housing defining a flow path for the gas, said housing having an inlet port, a central axis and an outlet port;
• (b) An inlet flow straightener mounted in said flow path adjacent said inlet port to form a constant area passage which causes gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted downstream of said inlet flow straightener and adjacent thereto and including a measuring rotor for rotation about the axis of said housing;
• said measuring rotor having turbine blades mounted thereon at blade angles which cause it to rotate in one direction with respect to the axis of said housing at a speed approximately proportional to the velocity of the gas flowing through said housing;
• (d) A reference flow straightener mounted in said housing downstream of said measuring rotor to form a constant area passage having an area approximately equal to that of the passage formed by said inlet flow straightener to cause gas from said measuring rotor to flow substantially axially in said housing;
• (e) A reference rotor mounted downstream of said reference flow straightener and adjacent thereto for rotation about the axis of said housing;
• said reference rotor having turbine blades mounted thereon with blade angles which cause said reference rotor to rotate in a direction opposite the direction of rotation of said measuring rotor at a speed approximately proportional to the velocity of gas flowing through said housing;
• (f) A measuring signal generator responsive to said measuring rotor for generating a measuring signal having its frequency f.sub.meas proportional to the speed of rotation of said measuring rotor;
• (g) A reference signal generator responsive to said reference rotor generating a reference signal having its frequency f.sub.ref proportional to the speed of rotation of said reference rotor;
• and
• (h) A signal processor responsive to said measuring signal generator and said reference signal generator for determining the accuracy of said gas turbine meter according to the formula:
• ##EQU10## where at the operating conditions of the measuring rotor and reference rotor,
• K.sub.meas is the K factor of the measuring rotor,
• K.sub.ref is the K factor of the reference rotor, and
• Accuracy.sub.cal is the accuracy of the mechanical output of the measuring rotor determined during calibration of the meter.

A gas turbine meter for measuring the volume of a stream of gas flowing therethrough comprising:

• (a) An elongated, cylindrical housing defining a flow path for the gas, said housing having an inlet port, a central axis and an outlet port;
• (b) An inlet flow straightener mounted in said flow path adjacent said inlet port to form a constant area passage which causes gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted downstream of said inlet flow straightener and adjacent thereto and including a measuring rotor for rotation about the axis of said housing;
• said measuring rotor having turbine blades mounted thereon at blade angles which cause it to rotate in one direction with respect to the axis of said housing at a speed approximately proportional to the velocity of the gas flowing through said housing;
• (d) A reference flow straightener mounted in said housing downstream of said measuring rotor to form a constant area passage having an area approximately equal to that of the passage formed by said inlet flow straightener to cause gas from said measuring rotor to flow substantially axially in said housing;
• (e) A reference rotor mounted downstream of said reference flow straightener and adjacent thereto for rotation about the axis of said housing;
• said reference rotor having turbine blades mounted thereon at approximately 18.5.degree. blade angles which cause said reference rotor to rotate in a direction opposite the direction of rotation of said measuring rotor at a speed less than the speed of said measuring rotor approximately proportional to the velocity of gas flowing through said housing;
• (f) A measuring signal generator responsive to said measuring rotor for generating a measuring signal proportional to the speed of rotation of said measuring rotor;
• (g) A reference signal generator responsive to said reference rotor generating a reference signal proportional to the speed of rotation of said reference rotor;
• and
• (h) A signal processor responsive to said measuring signal generator and reference signal generator for providing an indication of the accuracy of said gas turbine meter based on the quotient of the measuring signal divided by the reference signal.

A gas turbine meter for measuring the volume of a stream of gas flowing therethrough comprising:

• (a) An elongated, cylindrical housing defining a flow path for the gas, said housing having an inlet port, a central axis and an outlet port;
• (b) An inlet flow straightener mounted in said flow path adjacent said inlet port to form a constant area passage which causes gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted downstream of said inlet flow straightener and adjacent thereto and including a measuring rotor for rotation about the axis of said housing;
• said measuring rotor having turbine blades mounted thereon at blade angles which cause it to rotate in one direction with respect to the axis of said housing at a speed approximately proportional to the velocity of the gas flowing through said housing;
• (d) A reference flow straightener mounted in said housing downstream of said measuring rotor to form a constant area passage having an area approximately equal to that of the passage formed by said inlet flow straightener to cause gas from said measuring rotor to flow substantially axially in said housing;
• said reference rotor flow straightener including a central housing, a plurality of fins extending radially and outwardly from said central housing and a cylindrical flow guide mounted on the radial ends of said fins and extending over said reference rotor;
• (e) A reference rotor mounted downstream of said reference flow straightener and adjacent thereto for rotation about the axis of said housing;
• said reference rotor having turbine blades mounted thereon with blade angles which cause said reference rotor to rotate in a direction opposite the direction of rotation of said measuring rotor at a speed approximately proportional to the velocity of gas flowing through said housing;
• (f) A measuring signal generator responsive to said measuring rotor for generating a measuring signal proportional to the speed of rotation of said measuring rotor;
• (g) A reference signal generator responsive to said reference rotor generating a reference signal proportional to the speed of rotation of said reference rotor;
• and
• (h) A signal processor responsive to said measuring signal generator and reference signal generator for providing an indication of the accuracy of said gas turbine meter based on the quotient of the measuring signal divided by the reference signal.

A gas turbine meter for measuring the volume of a stream of gas flowing therethrough comprising:

• (a) An elongated, cylindrical housing defining a flow path for the gas, said housing having an inlet port, a central axis and an outlet port;
• (b) An inlet flow straightener mounted in said flow path adjacent said inlet port to form a constant area passage which causes gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted downstream of said inlet flow straightener and adjacent thereto and including a measuring rotor at its upstream end which rotates about the axis of said housing;
• said measuring rotor having turbine blades with their upstream tips extending toward said inlet port and mounted thereon at blade angles which cause said rotor to rotate in one direction with respect to the axis of said housing at a speed approximately proportional to the velocity of the gas flowing through said housing;
• (d) Said measuring cartridge having an interior surface forming the flow path for gas to be measured, said interior surface having a conical axial cross section around said turbine blades which over a predetermined length from its upstream end is tapered away from said turbine blades at an angle between about 5.degree. and about 7.degree.;
• (e) A mechanism included as a portion of said measuring cartridge which locates said upstream tips of said turbine blades at a preselected position with respect to said tapered interior surface of said cartridge;
• (f) A reference flow straightener mounted in said housing downstream of said measuring rotor to form a constant area passage having an area approximately equal to that of the passage formed by said inlet flow straightener to cause gas from said measuring rotor to flow substantially axially in said housing;
• (g) A reference rotor mounted downstream of said reference flow straightener and adjacent thereto for rotation about the axis of said housing;
• said reference rotor having turbine blades mounted thereon with blade angles which cause said reference rotor to rotate in a direction opposite the direction of rotation of said measuring rotor at a speed approximately proportional to the velocity of gas flowing through said housing;
• (h) A measuring signal generator responsive to said measuring rotor for generating a measuring signal proportional to the speed of rotation of said measuring rotor;
• (i) A reference signal generator responsive to said reference rotor generating a reference signal proportional to the speed of rotation of said reference rotor;
• and
• (j) A signal processor responsive to said measuring signal generator and reference signal generator for providing an indication of the accuracy of said gas turbine meter based on the quotient of the measuring signal divided by the reference signal.

A gas turbine meter for measuring the volume of a stream of gas flowing therethrough comprising:

• (a) An elongated, cylindrical housing defining a flow path for the gas, said housing having an inlet port, a central axis and an outlet port;
• (b) An inlet flow straightener mounted in said flow path adjacent said inlet port to form a constant area passage which causes gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted downstream of said inlet flow straightener and adjacent thereto and including a measuring rotor for rotation about the axis of said housing;
• said measuring rotor having turbine blades mounted thereon at blade angles which cause it to rotate in one direction with respect to the axis of said housing at a speed approximately proportional to the velocity of the gas flowing through said housing;
• (d) Said measuring rotor mounted at the upstream end of said measuring cartridge and including a cylindrical rotor hub on which said turbine blades are mounted;
• (e) Said measuring cartridge including a cylindrical chamber concentric with said rotor which has an upstream end through which said measuring rotor is mounted and has a downstream end, the outside diameter of said cylindrical chamber being slightly less than the inside diameter of said rotor hub, with the axial length of said cylindrical chamber being such that its upstream end extends beneath said rotor hub when said measuring chamber is mounted within said measuring cartridge, and that portion of the outside surface of said measuring chamber in the vicinity of said rotor being continuous and smooth so that contamination cannot accumulate near the clearance between said rotor hub and said cylindrical chamber;
• (f) Rotor bearings for said measuring rotor and a shaft for connecting said measuring rotor to said bearings;
• (g) Said cylindrical chamber including a structure within it for mounting said rotor bearings downstream of said location where said shaft is connected to said measuring rotor, with the downstream end of said structure being closed to the flow of gas through said gas turbine meter when said bearings are mounted within said structure;
• (h) A reference flow straightener mounted in said housing downstream of said measuring rotor to form a constant area passage having an area approximately equal to that of the passage formed by said inlet flow straightener to cause gas from said measuring rotor to flow substantially axially in said housing;
• (i) A reference rotor mounted downstream of said reference flow straightener and adjacent thereto for rotation about the axis of said housing;
• said reference rotor having turbine blades mounted thereon with blade angles which cause said reference rotor to rotate in a direction opposite the direction of rotation of said measuring rotor at a speed approximately proportional to the velocity of gas flowing through said housing;
• (j) A measuring signal generator responsive to said measuring rotor for generating a measuring signal proportional to the speed of rotation of said measuring rotor;
• (k) A reference signal generator responsive to said reference rotor generating a reference signal proportional to the speed of rotation of said reference rotor;
• and
• (l) A signal processor responsive to said measuring signal generator and reference signal generator for providing an indication of the accuracy of said gas turbine meter based on the quotient of the measuring signal divided by the reference signal.

A gas turbine meter for measuring the volume of flow of a stream of gas comprising:

• (a) An elongated cylindrical housing defining a flow path for the gas, said elongated housing having an inlet port, a central axis and outlet port;
• (b) A flow straightening assembly mounted in said housing adjacent said inlet port to form a passage having a constant area to cause gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted adjacent said flow straightening assembly in said housing;
• (d) A measuring rotor mounted within said measuring cartridge and at the upstream end of said measuring cartridge;
• (e) Said measuring rotor having turbine blades mounted thereon with blade angles which cause said measuring rotor to rotate at a speed approximately proportional to the velocity of gas flowing through said housing, said turbine blades having upstream tips extending toward said inlet port;
• (f) Said measuring cartridge having an interior surface forming the flow path for gas to be measured, said interior surface having a conical axial cross section around said turbine blades which over a predetermined length from its upstream end is tapered in the range of between about five degrees and about seven degrees away from said turbine blades;
• and
• (g) A mechanism included as a portion of said measuring cartridge which locates said upstream tips of said turbine blades at a preselected position with respect to said tapered interior surface of said cartridge.

A gas turbine meter for measuring the volume of flow of a stream of gas comprising:

• (a) An elongated cylindrical housing defining a flow path for the gas, said elongated housing having an inlet port and outlet port;
• (b) A flow straightening assembly mounted in said housing adjacent said inlet port to form a passage having a constant area to cause gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted adjacent said first flow straightener assembly in said housing;
• (d) A measuring rotor mounted within said measuring cartridge and at the upstream end of said measuring cartridge;
• (e) Said measuring rotor having turbine blades mounted thereon with blade angles which cause said measuring rotor to rotate at a speed proportional to the velocity of gas flowing through said housing, said turbine blades having upstream tips extending toward said inlet port;
• (f) Said measuring cartridge having an interior surface which defines the flow path of the gas to be measured, said interior surface having a conical shape, adjacent the location where said upstream tips of said turbine blades are located, which gradually increases in diameter in a range of between about five degrees and about seven degrees over a predetermined length from the upstream end of said measuring cartridge to such an extent that the accuracy of said meter can be changed by changing the clearance between said turbine blades and said interior surface of said housing;
• and
• (g) A mechanism included as a portion of said measuring cartridge which locates a secured position of said upstream tips of said turbine blades of said metering rotor axially within the preselected distance of said interior surface.

A gas turbine meter for measuring the volume of flow of a stream of gas through a pipe comprising:

• (a) An elongated housing defining a flow path for the gas, said elongated housing having an inlet port and outlet port;
• (b) A flow straightener mounted in said housing adjacent said inlet port;
• (c) A measuring cartridge mounted downstream of said first flow straightener and adjacent it in said housing;
• (d) A measuring rotor mounted within said measuring cartridge and at the upstream end of said measuring cartridge and includes a cylindrical rotor hub and a plurality or turbine blades mounted on said rotor rub;
• (e) Said measuring cartridge including a cylindrical chamber concentric with said rotor which has an upstream end through which said measuring rotor is mounted and has a downstream end, the outside diameter of said cylindrical chamber being slightly less than the inside diameter of said rotor bush, with the axial length of said cylindrical chamber being such that its upstream end extends beneath said rotor hub when said measuring rotor is mounted within said measuring cartridge, and that portion of the outside surface of said cylindrical chamber in the vicinity of said rotor being continuous and smooth so that contamination cannot accumulate near the clearance between said rotor hub and said cylindrical chamber;
• (f) Rotor bearings for said measuring rotor and a shaft for connecting said measuring rotor to said bearings;
• and
• (g) Said cylindrical chamber including a structure within it for mounting said rotor bearings downstream of the location where said shaft is connected to said measuring rotor, with the downstream end of said structure being closed to the normal flow of gas through said gas turbine meter when said bearings are mounted within said structure.

A method of using a computer processor to analyze the accuracy of a gas turbine meter having a measuring rotor and a reference rotor rotating substantially independently of the effects of the measuring rotor comprising the steps of:

• (a) Selecting measuring signals from the measuring rotor approximately proportional to the speed of rotation of the measuring rotor;
• (b) Selecting reference signals from the reference rotor approximately proportional to the speed of rotation of the reference rotor;
• (c) Using a signal processor to determine the flowrate through the gas turbine meter and adjusting the flowrate to a level desired for determining the accuracy of the meter;
• and
• (d) Using a signal processor to process the measuring signals and the reference signals to determine the accuracy of the gas turbine meter based on the quotient of the measuring signals divided by the reference signals.

A method of using a computer processor to analyze the accuracy of a gas turbine meter having a measuring rotor and a reference rotor rotating substantially independently of the effects of the measuring rotor comprising the steps of:

• (a) Selecting measuring signals from the measuring rotor having a frequency f.sub.meas approximately proportional to the speed of rotation of the measuring rotor;
• (b) Selecting reference signals from the reference rotor having a frequency f.sub.ref approximately proportional to the speed of rotation of the reference rotor;
• and
• (c) Using a signal processor to process the measuring signal and the reference signal to determine the accuracy of the gas turbine meter according to the formula:
• ##EQU13## where at the operating conditions of the measuring rotor and reference rotor,
• K.sub.meas is the K factor of the measuring rotor,
• K.sub.ref is the K factor of the reference rotor, and
• Accuracy.sub.cal is the accuracy of the measuring rotor determined during calibration of the meter.

A method of using a computer processor to analyze the accuracy of any one of a plurality of gas turbine meters each having a measuring rotor and a reference rotor rotating substantially independently of the effects of the measuring rotor comprising the steps of:

• (a) Choosing the gas turbine meter whose accuracy is to be analyzed;
• (b) Selecting from the chosen gas turbine meter the measuring signals from the measuring rotor approximately proportional to the speed of rotation of the measuring rotor;
• (c) Selecting from the chosen gas turbine meter the reference signals from the reference rotor approximately proportional to the speed of rotation of the reference rotor;
• (d) Using a signal processor to determine the flowrate through the chosen gas turbine meter and adjusting the flowrate to a level desired for determining the accuracy of the meter;
• and
• (e) Using a signal processor to process the measuring signals and the reference signals to determine the accuracy of the chosen gas turbine meter based on the quotient of the measuring signals divided by the reference signals.

A method of using a computer processor to analyze the accuracy of any one of a plurality of gas turbine meters each having a measuring rotor and a reference rotor rotating substantially independently of the effects of the measuring rotor comprising the steps of:

• (a) Choosing the gas turbine meter whose accuracy is to be analyzed;
• (b) Selecting from the chosen gas turbine meter measuring signals from the measuring rotor having a frequency f.sub.meas approximately proportional to the speed of rotation of the measuring rotor;
• (c) Selecting from the chosen gas turbine meter reference signals from the reference rotor having a frequency f.sub.ref approximately proportional to the chosen speed of rotation of the reference rotor;
• and
• (c) Using a signal processor to process the measuring signal and the reference signal to determine the accuracy of the chosen gas turbine meter according to the formula:
• ##EQU17## where at the operating conditions of the measuring rotor and reference rotor,
• K.sub.meas is the K factor of the measuring rotor,
• K.sub.ref is the K factor of the reference rotor, and
• Accuracy.sub.cal is the accuracy of the measuring rotor determined during calibration of the meter.

A gas turbine meter for measuring the volume of a stream of gas flowing therethrough which is adapted to be used with a signal processor responsive to a measuring signal generator and a reference signal generator which are components of the gas turbine meter for providing an indication of the accuracy of the gas turbine meter based on the quotient of the measuring signal divided by the reference signal, the gas turbine meter comprising:

• (a) An elongated, cylindrical housing defining a flow path for the gas, said housing having an inlet port, a central axis and an outlet port;
• (b) An inlet flow straightener mounted in said flow path adjacent said inlet port to form a constant area passage which causes gas from said inlet port to flow substantially axially in said housing;
• (c) A measuring cartridge mounted downstream of said inlet flow straightener and adjacent thereto and including a measuring rotor for rotation about the axis of said housing;
• said measuring rotor having turbine blades mounted thereon at blade angles which cause it to rotate in one direction with respect to the axis of said housing at a speed approximately proportional to the velocity of the gas flowing through said housing;
• (d) A reference flow straightener mounted in said housing downstream of said measuring rotor to form a constant area passage having an area approximately equal to that of the passage formed by said inlet flow straightener to cause gas from said measuring rotor to flow substantially axially in said housing;
• (e) A reference rotor mounted downstream of said reference flow straightener and adjacent thereto for rotation about the axis of said housing;
• said reference rotor having turbine blades mounted thereon with blade angles which cause said reference rotor to rotate in a direction opposite the direction of rotation of said measuring rotor at a speed less than the speed of said measuring rotor which is approximately proportional to the velocity of gas flowing through said housing;
• (f) A measuring signal generator adapted to be coupled to the signal processor and responsive to said measuring rotor for generating a measuring signal proportional to the speed of rotation of said measuring rotor;
• and
• (g) A reference signal generator adapted to be coupled to the signal processor and responsive to said reference rotor generating a reference signal proportional to the speed of rotation of said reference rotor.