Modern Mechanism: Exhibiting the Latest Progress in Machines, Motors, and the Transmission of Power, Being a Supplementary Volume to Appletons' Cyclopaedia of Applied Mechanics

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Park Benjamin
D. Appleton, 1892 - 924 стор.

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Сторінка 66 - Before beginning a test, the boiler and chimney should be thoroughly heated to their usual working temperature. If the boiler is new, it should be in continuous use at least a week before testing, so as to dry the mortar thoroughly and heat the walls.
Сторінка 66 - ... portion. It is desirable that at the same time the amount of water fed into the boiler should be accurately noted and recorded, including the height of the water in the boiler and the average pressure of steam and temperature of feed during the time. By thus recording the amount of water...
Сторінка 67 - In all tests in which accuracy of results is important, calorimeter tests should be made of the percentage of moisture in the steam, or of the degree of superheating. At least ten such tests should be made during the trial of the boiler, or so many as to reduce the probable average error to less...
Сторінка 247 - ... valve as the sewage rises ; and so the action goes on as long as there is sewage to flow. The position of the...
Сторінка 67 - In tests for purposes of scientific research, in which the determination of all the variables entering into the test is desired, certain observations should be made which are in general unnecessary for ordinary tests.
Сторінка 66 - The conditions of the boiler and furnace in all respects should be, as nearly as possible, the same at the end as at the beginning of the test. The steam pressure should be the same ; the water level the same ; the fire upon the grates should be the same in quantity and condition ; and the walls, flues, etc., should be of the same temperature Two methods of obtaining the desired equality of conditions of the fire may be used, viz.
Сторінка 66 - If the boiler is connected to the main steam pipe with other boilers, the safety valve on the boiler being tested should be set a few pounds higher than those of the other boilers, so that in case of a rise in pressure the other boilers may blow off and the pressure be reduced by closing their dampers, allowing the damper of the boiler being tested to remain open, and firing as usual. All the conditions should be kept as nearly uniform as possible, such as the force of draft, pressure of steam, and...
Сторінка 66 - When very good coal is used, and the combustion not too rapid, a ten-hour test may be run without any cleaning of the grates, other than just before the beginning and just before the end of the test. But in case the grates have to be cleaned during the test, the intervals between one cleaning and another should be uniform.
Сторінка 65 - Water meters, as a rule, should only be used as a check on other measurements. For accurate work, the water should be weighed or measured in a tank. 3. Thermometers and pyrometers for taking temperatures of air, steam, feedwater, waste gases, etc.
Сторінка 66 - Keep the Conditions Uniform. — The boiler should be run continuously, without stopping for meal-times or for rise or fall of pressure of steam due to change of demand for steam. The draught being adjusted to the rate of evaporation or combustion desired before the test is begun, it should be retained constant during the test by means of the damper. If the boiler is not connected to the same...

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