Chapter XXXVII: Section 44: INDICATING SPEEDS, &c

=784 & 785. Hand (portable) indicator,= to indicate speed of revolution of a shaft, &c., by simple wheel work and dial plate.

=786. Governor gauge,= indicates the speed by the angle of the balls moving a finger on a vertical scale.

=787. Steam engine indicator,= of which there are many varieties. Macnaught’s, Richards’, Darke’s, Kraft’s, Casartelli’s, &c., are examples, in which a small steam piston operates a marking point by the varying pressure of steam acting against a spring; the paper is usually coiled on a cylinder having a reciprocating motion by a string from the engine.

=788. Morin’s dynamometer.= Consists of two belt pulleys connected by a spring; one receives the strain of driving belt, and the other transmits it, the spring indicating the tension on the belts.

=789. Regnier’s dynamometer= indicates the tension on the connections by contraction of the spring operating a dial plate.

=790. Bourdon tube pressure indicator.= The tube is of flat section, and its curved portion expands with the pressure, operating a finger on the dial by rackwork.

=791. Worm gear and dial= to register the number of revolutions. See No. 1559.

Other forms of pressure gauges are--1st. The mercurial gauge, in which
the pressure is indicated by the height of a column of mercury in a
glass tube. 2nd. The water gauge, in which a column of water replaces
the mercury. 3rd. The spring balance (see No. 1729). See also Nos.
1730, 1728.

=792 & 793. Winding engines= are provided with indicators on the principle of No. 744. The travelling nut has a pointer whose position on a vertical graduated scale shows the position of the cage in the pit.

Vertical scale indicators are also employed to show the level of water
in tanks, reservoirs, &c. See No. 1730.

Water tube indicators are employed to show the level of water in
boilers, &c., as also gauge cocks fixed at various heights in the
boiler.