An automatic analogue computor for the solution of mine ventilation networks
D R Scott, R F Hudson · Journal of Scientific Instruments · 1953
Mine ventilation networks are analogous to electrical networks containing non-linear elements. In the electrical computing machine described, the aerodynamic resistance of each mine roadway is represented by a variable ohmic resistance which is caused to follow a non-linear law by means of a servomechanism. The element may be simply adjusted to represent the resistance of any roadway in the practical range. The servomechanism consists of a differential relay in which the current flow through the element is compared with the current in a reference circuit. When the currents are out of balance a magnetic clutch is operated and the circular potentiometer comprising the element is rotated in an appropriate direction by an electric motor until balance is achieved. Reference is also made to a hand-operated linear resistance network which has been developed to deal with ventilation network problems.