Savery's patent, called "The Miner's Friend
," was for a water pump that functioned by admitting steam to a chamber, condensing it by cooling the outside of the chamber, allowing the partial vacuum to siphon water into the vessel, and then lifting the water with steam pressure.
Besides, it took a great deal of fuel to heat water to form the necessary steam, and most of the coal obtained with the help of the Miner's Friend
had to be used in operating the device.
Savery's Miner's Friend
was too inefficient and too dangerous.