Fig. 3395.
When one cylinder is placed above the other, as in [Fig. 3395], r being the high pressure and s the low pressure piston, no receiver is employed, the steam passing direct from the high pressure cylinder through the pipe p to the low pressure steam chest c. The high pressure steam valve v and the low pressure valve v are on the same stem, a cut off valve v′ being provided for the high pressure cylinder.
3. Triple expansion engines have three cylinders, a high pressure, an intermediate, and a low pressure cylinder.
In a triple expansion engine the intermediate cylinder receives the steam that is exhausted from the high pressure cylinder, and expands it further. The low pressure cylinder receives its steam from the exhaust of the intermediate cylinder, and exhausts into the condenser.
Fig. 3396.