Page:Motors and motor-driving (1902).djvu/291

Rh We have already shown that in most cars the forcing of the petrol supply to the burner does not require a constantly acting pump, as an air-tank occasionally pumped up by hand provides enough pressure to force the petrol through the vaporiser to the burner, but in the Serpollet the paraffin (which is under air pressure) is also pumped to the burner as well as the water to the generator. The arrangement is shown at fig. 13. It has been found that six parts of water require one part of paraffin to vaporise them in the Serpollet. The oil pump is smaller than the water pump, and both are connected by links 1



and 1 to the lever, which hinges on the fulcrum. The lever is moved up and down by the link 1, which is connected to the arm. On the arm is a roller, which is forced up and down by eccentric discs or cams  on the shaft , which is rotated from the engine by the toothed or cogged wheel. The result is that, as the lever is hinged at, its up and down motion is greater at 1 than at 1, so that the water pump w always has a longer stroke than the oil pump.

When more steam is required in the Serpollet, it simply means that more water must be forced into the heated generator