ILLUMINATING DUTY.--The illuminating value of ordinary self-luminous acetylene burners in different sizes has been examined by various photometrists. For burners of the Naphey type Lewes gives the following table:
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| | | | | |
| | | Gas | | Candles |
| Burner. | Pressure, | Consumed, | Light in | per |
| | Inches | Cubic Feet | Candles. | Cubic Foot. |
| | | per Hour. | | |
|_________|___________|____________|__________|_____________|
| | | | | |
| No. 6 | 2.0 | 0.155 | 0.794 | 5.3 |
| " 8 | 2.0 | 0.27 | 3.2 | 11.6 |
| " 15 | 2.0 | 0.40 | 8.0 | 20.0 |
| " 25 | 2.0 | 0.65 | 17.0 | 26.6 |
| " 30 | 2.0 | 0.70 | 23.0 | 32.85 |
| " 42 | 2.0 | 1.00 | 34.0 | 34.0 |
|_________|___________|____________|__________|_____________|
From burners of the Billwiller type Lewes obtained in 1899 the values:
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| | | | | |
| | | Gas | | Candles |
| Burner. | Pressure, | Consumed, | Light in | per |
| | Inches | Cubic Feet | Candles. | Cubic Foot. |
| | | per Hour. | | |
|_________|___________|____________|__________|_____________|
| | | | | |
| No. 1 | 2.0 | 0.5 | 7.0 | 11.0 |
| " 2 | 2.0 | 0.75 | 21.0 | 32.0 |
| " 3 | 2.0 | 0.75 | 28.0 | 37.3 |
| " 4 | 3.0 | 1.2 | 48.0 | 40.0 |
| " 5 | 3.5 | 2.0 | 76.0 | 38.0 |
|_________|___________|____________|__________|_____________|
Neuberg gives these figures for different burners (1900) as supplied by Pintsch:
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| | | | | |
| | Gas | | Candles | |
| Burner. | Pressure, | Consumed, | Light in | per |
| | Inches | Cubic Feet | Candles. | Cubic Foot. |
| | | per Hour. | | |
|____________________|___________|____________|__________|_____________|
| | | | | |
| No. 0, slit burner | 3.9 | 1.59 | 59.2 | 37.3 |
| " 00000 fishtail | 1.6 | 0.81 | 31.2 | 38.5 |
| Twin burner No. 1 | 3.2 | 0.32 | 13.1 | 40.8 |
| " " " 2 | 3.2 | 0.53 | 21.9 | 41.3 |
| " " " 3 | 3.2 | 0.74 | 31.0 | 41.9 |
| " " " 4 | 3.2 | 0.95 | 39.8 | 41.9 |
|____________________|___________|____________|__________|_____________|
The actual candle-power developed by each burner was not quoted by Neuberg, and has accordingly been calculated from his efficiency values. It is noteworthy, and in opposition to what has been found by other investigators as well as to strict theory, that Neuberg represents the efficiencies to be almost identical in all sizes of the same description of burner, irrespective of the rate at which it consumes gas.
Writing in 1902, Capelle gave for Stadelmann's twin injector burners the following figures; but as he examined each burner at several different pressures, the values recorded in the second, third, and fourth columns are maxima, showing the highest candle-power which could be procured from each burner when the pressure was adjusted so as to cause consumption to proceed at the most economical rate. The efficiency values in the fifth column, however, are the mean values calculated so as to include all the data referring to each burner. Capelle's results have been reproduced from the original on the basis that 1 bougie décimale equals 0.98 standard English candle, which is the value he himself ascribes to it (1 bougie décimale equals 1.02 candles is the value now accepted).
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| | | | | |
| Nominal | Best | Actual Consumption | Maximum | Average |
| Consumption,| Pressure| at Stated Pressure. | Light in | Candles per|
| Litres. | Inches. | Cubic Feet per Hour.| Candles. | Cubic Foot.|
|_____________|_________|_____________________|__________|____________|
| | | | | |
| 10 | 3.5 | 0.40 | 8.4 | 21.1 |
| 15 | 2.8 | 0.46 | 16.6 | 33.3 |
| 20 | 3.9 | 0.64 | 25.1 | 40.0 |
| 25 | 3.5 | 0.84 | 37.8 | 46.1 |
| 30 | 3.5 | 0.97 | 48.2 | 49.4 |
|_____________|_________|_____________________|__________|____________|
Some testings of various self-luminous burners of which the results were reported by R. Granjon in 1907, gave the following results for the duty of each burner, when the pressure was regulated for each burner to that which afforded the maximum illuminating duty. The duty in the original paper is given in litres per Carcel-hour. The candle has been taken as equal to 0.102 Carcel for the conversion to candles per cubic foot.