|
|______________________________|_____________________|____________________|
| | | |
| Direct-acting Pump feeding | | |
| water at 60 degrees without | | |
| a heater | 1.000 | .0 |
| | | |
| Injector feeding water at | | |
| 150 degrees without a heater | .985 | 1.5 |
| Injector feeding through a | | |
| heater in which the water is | | |
| heated from 150 to 200 | | |
| degrees | .938 | 6.2 |
| | | |
| Direct-acting Pump feeding | | |
| water through a heater in | | |
| which it is heated from 60 | | |
| to 200 degrees | .879 | 12.1 |
| | | |
| Geared Pump run from the | | |
| engine, feeding water | | |
| through a heater in which it | | |
| is heated from 60 to 200 | | |
| degrees | .868 | 13.2 |
|______________________________|_____________________|____________________|

The injector, considered only in the light of a combined heater and
pump, is claimed to have a thermal efficiency of 100 per cent, since all
of the heat in the steam used is returned to the boiler with the water.
This claim leads to an erroneous idea. If a pump is used in feeding the
water to a boiler and the heat in the exhaust from the pump is imparted
to the feed water, the pump has as high a thermal efficiency as the
injector. The pump has the further advantage that it uses so much less
steam for the forcing of a given quantity of water into the boiler that
it makes possible a greater saving through the use of the exh