Gas calorimeter and wobbe index meter
AssigneePanametrics, Inc.
InventorEmilio Meyer
Life of this patent
Estimating the term…
Abstract
Apparatus for measuring the combustion characteristics of a gaseous fuel. Wobbe index and calorific value are measured with a fast response time by maintaining a stoichiometric mixture in a mixer supplied with the gaseous fuel at a constant pressure together with ambient air. The pressure of ambient air is controlled by measuring the residual oxygen from combustion of the mix and employing variations in that measured value to control the ambient air supplied to the mixer. The control signal for the ambient air is proportional to the Wobbe index. A separate measurement of the oxygen in the stoichiometric mix provides a signal proportional to the calorific fuel value.
Claims11
Apparatus for measuring the combustion characteristics, including the Wobbe Index, of a gaseous fuel comprising:
- a pressurized source of said gaseous fuel;
- an orifice connected to said pressurized source for passing said gaseous fuel;
- a pressure regulator positioned between said source and said orifice to control the pressure of said gaseous fuel supplied to said orifice;
- a mixer having first, second and third gas inputs and a gas output, said gaseous fuel from said orifice being supplied as a first input to said mixer;
- a first source of air supplied as a second input to said mixer;
- a second source of air supplied as a third input to said mixer at a predetermined, substantially constant pressure;
- an oxygen sensor for burning the output gas from said mixer, measuring residual oxygen and providing an output signal proportional to said measured residual oxygen;
- means for coupling said mixer output to said oxygen sensor;
- a controller means responsive to the output signal from said oxygen sensor for controlling the pressure of said first source of air in response thereto to maintain a stoichiometrically balanced air/fuel mixture in said mixer;
- the output signal from said oxygen sensor providing a measure of said Wobbe Index of said gaseous fuel.
Apparatus for measuring the combustion characteristics, including the calorific value, of a gaseous fuel comprising;
- a pressurized source of said gaseous fuel;
- a mixer having first, second and third gas inputs and a gas output;
- means connected to said source for supplying said gaseous fuel at a constant volume of flow as a first input to said mixer;
- a first source of air supplied as a second input to said mixer;
- a second source of air supplied as a third input to said mixer at a predetermined, substantially constant pressure;
- an oxygen sensor for burning the output gas from said mixer, measuring residual oxygen and providing an output signal proportional to said measured residual oxygen;
- means for coupling said mixer output to said oxygen sensor;
- a controller means responsive to the output signal from said oxygen sensor for controlling the pressure of said first source of air in response thereto to maintain a stoichiometrically balanced air/fuel mixture in said mixer;
- the output signal from said oxygen sensor providing a measure of the said calorific value of said gaseous fuel.
A method for measuring the combustion characteristics, including the Wobbe Index, of a gaseous fuel supplied from a fuel sample inlet comprising the steps of;
- a) passing said gaseous fuel from said fuel sample inlet at a controlled pressure through an orifice;
- b) coupling the gaseous fuel from said orifice as a first input to a mixer;
- c) supplying air from a first source of air as a second input to said mixer to create a stoichiometrically balanced mix in said mixer;
- d) supplying air from a second source of air supplied as a third input to said mixer, at a predetermined substantially constant pressure;
- e) coupling said mixer output to an oxygen sensor for measuring residual oxygen by burning the output gas from said mixer, and providing an output signal proportional to the measured residual oxygen;
- f) controlling the pressure of said first source of air in response to said output signal to maintain a stoichiometrically balanced air/fuel mixture in said mixer and measuring said output signal from said oxygen sensor as a measure of the said Wobbe index of said gaseous fuel.
A method for measuring the combustion characteristics, including the calorific value, of a gaseous fuel supplied from a fuel sample inlet comprising the steps of;
- a) passing said gaseous fuel at a controlled flow volume from said fuel sample inlet as a first input to said mixer;
- b) supplying air from a first source of air as a second input to said mixer at a pressure to create a stoichiometrically balanced mix in said mixer;
- c) supplying air from a second source of air supplied as a third input to said mixer, at a predetermined substantially constant pressure;
- d) coupling said mixer output to an oxygen sensor for measuring residual oxygen by burning the output gas from said mixer, and providing an output signal proportional to the measured residual oxygen;
- e) controlling the pressure of said first source of air in response to said output signal to maintain a stoichiometrically balanced air/fuel mixture in said mixer and measuring said output signal from said oxygen sensor as a measure of the said calorific value of said gaseous fuel.
Dependencies are inferred from the claim text.