A Barker's mill or Scottish turbine is a hydraulic machine on the principle of what is known as the hydraulic tourniquet. This consists of an upright vessel free to rotate about a vertical axis, and having at its lower end two discharging pipes projecting horizontally on either side and bent in opposite directions at the ends, through which the water is discharged horizontally, the direction of discharge being mainly at right angles to a line joining the discharging orifice to the axis. The backward pressures at the bends of the tubes, arising from the two issuing jets of water, cause the apparatus to revolve in an opposite direction to the issuing fluid. Research Barker's Mill
A Barker's Mill is an apparatus based upon the principal of the hydraulic tourniquet. It consists of a vessel containing water and free to rotate about vertical axis. Near its base are provided outlet pipes through which the water is discharged horizontally, in a direction tangential to a circle having its centre at the axis of rotation of the vessel. The mill operates upon the reaction principle, the unbalanced pressures at the discharge orifices causing the vessel to rotate. A horizontal turbine wheel having curved outlet pipes around its periphery acts upon this principle. Research Barker's Mill
Hydraulics is that part of mechanical science which has to do with conducting, raising, and confining water, or of applying it as a motive power. It thus has to do with the flow of water in pipes or channels, and with the various machines in which water is utilized, such as water-wheels, pumps, turbines, the archimedean screw, the Barker's mill, the hydraulic ram, the hydraulic crane, the hydraulic or hydrostatic press, etc. Research Hydraulics
A steam engine is an apparatus for converting heat energy into useful work by means of th expansive force of steam.
The earliest recorded attempt to construct a working steam engine was conducted by Hero of Alexandria about 130BC, whose engine was later adapted for use with water instead of steam and became known as the Barker's Mill. Giobvanni della Porta at the beginning of the 17th century adapted another of Hero's inventions, his famous fountain replacing the expanded air used in the original with steam. In 1655 the marquess of Worcester is credited with the invention of a steam engine for pumping water.
The first practical step towards the application of steam power as a motive force was taken by Thomas Savery who patented and exhibited a model of his steam engine at the Royal Institution in London in 1698. Thomas Savery's engine essentially consisted of a cylinder into which steam entered and forced out a charge of water, sucked into it by a previous charge of steam that was suddenly condensed by a jet of cold water allowed to flow over the outer surface of the cylinder. Thomas Savery's steam engines were erected in many parts of Great Britain to pump water. However, Dionysius Papin had published a design for a high-pressure steam engine in 1690, and it is probable that Savery took the plan from him.
Whether designed by Thomas Savery or Dionysius Papin, the early steam engine described was considerably improved by Thomas Newcomen and John Cawley who introduced a piston, driven down by atmospheric pressure as a vacuum was created in the cylinder by the condensation of the steam. This improved steam engine was also used for pumping water.
In 1769 James Watt patented a double-condenser which was another major improvement upon the efficiency of the steam engine, and in 1804 Richard Trevithick applied the steam engine to run along rails. Research Steam Engine
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