Originally Thomas Savery was concerned with the shipbuilding, so he invented a ship driven by a paddle wheel. Later he turned to the pump technology.
The steam pump
Savery built on the piston steam pump by Denis Papin and constructed a piston-free steam pump for which he under the name Miner 's Friend ( Miner's Friend ) received an English patent with the maturity of 14 years on July 2, 1698. The name of the pump is the result of a problem of time: The penetrating ground water had to be pumped out of the mines. This was done manually or by horse -driven Göpeln and waterworks. With increasing size and depth of the mines this dehydration was the decisive factor in the profitability of the mine. On June 14, 1699 Savery was able to demonstrate a model of his steam engine at a meeting of the Royal Society. In the same year extended the term of protection of all relevant patents in the Parliament on the Fire Engine Act ( Act driven by fire machines): Savery's patent expired in 1733, therefore, only from. The shortage that his patent did not contain a functional description of a sketch, he resolved beside the mentioned demonstration with a discussion of The Miner 's Friend; or, An Engine to Raise Water by Fire ( " miner's friend or a machine for raising water by fire "). However, also be extended at runtime patent extended generally to all machines that lift the water with the aid of fire.
Principle of operation
Saverys pump is driven by steam, which has been usually produced around the pump by means of steam boiler. The actual pump consists of two pressure vessels, which are connected via non-return valves with the suction (intake ) and the pressure line (outlet). In operation, the pressure vessels are alternately energized by a control valve with steam. The hot steam expands in the vessel, and forces the water through a check valve into the pressure line. The supply of steam is stopped. With the onset of condensation, the pressure is no longer sufficient for this purpose, the check valve closes the pressure line. To accelerate the condensation, the pressure vessel was cooled externally with water, this increased the pump frequency, so the pump ran faster. With a further condensation of the pressure in the container falls below the external pressure. This pressure difference forces the water from the suction pipe via the valve into the container. The incoming water results in a further condensation of the vapor. With opening of the control valve steam comes back again into the pressure vessel and the cycle begins.
The Savery pump also works with only a pressure vessel; However, the design with two pressure vessels has the advantage that the steam is uniformly decrease from the boiler. Continues to double naturally the pump power at double steam consumption. Even if the control valve was operated in the demonstrators hand, the series devices are controlled by means of floating bodies.
Problems and Efficiency
Savery was impressed by the performance of his machine; However, she had some serious shortcomings: You could lift the water column only at 12 meters; for greater depths had to be cascaded multiple pumps. The vapor pressure was needed at that time at the limit of what is possible, for which the steel and the rivets used at that time were responsible in addition to the solder joints. Therefore, the pump and especially the boiler frequently had to be repaired. By design, the heated steam and the water to be pumped. This had a thermodynamic efficiency at ppm level result, so that the pump could be practically used because of their large coal demand only in or near coal mines.
Cooperation with Newcomen
Savery's patent was so broad that he, who in 1712 invented the technically superior atmospheric steam engine, Thomas Newcomen, could impose on a partnership. In Newcomen's steam engine it is, just like the Papin, a piston -cylinder system.
It was not until 1872, the principle of the piston-free steam pump was a decisive development in the form of Pulsometers.