Specification of William Church : steam boilers and propellers for vessels.

  • Church, William.
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Specification of William Church : steam boilers and propellers for vessels. Source: Wellcome Collection.

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    Church's Improvements in Steam Boilers and Propelling Machinery. alternately by a sliding valve e, e, fitted to each end plate and working between it and the top or bottom cap or casing, the lower slider e being held up to the lower plate d by springs. I shall proceed to describe the construction of these end plates d, d, and the sliding valves *, e, with the method of actuating them. 5 Fig. 7 is a horizontal view of one of the end plates as it would appear on its outer surface j Fig. S is a section of the same, that is, about an inch of the thickness of the plate on the outside being removed, for the purpose of exhibiting the eduction apertures and recesses within the said plates ; Fig. 9 is one of the sliding valves detached, as it would appear on that side which acts against the 10 outer surface of the end plate. Let it now be supposed that the steam from the passage c, c, is in the act of entering the cylinder through the upper end plate (as in Fig. 5) in order to depress the piston: the upper sliding valve e, e, must be in such an advanced situation as shall leave the induction nppeitures open, when the steam, passing freely round the upper slide valve, will enter the 15 cylinder at the appertures /,/; at the same time the lower slide valve e,e, will have receded, shutting off the steam at the lower part of the cylinder and opening the apertures /,/, in the lower end plate cl to the recesses in the slide valve, and through them to the cavity and eduction passages of the end plate, from whence the volume of steam that had previously acted in raising the 20 piston will now pass off into the chamber g,g,g, within the jacket surrounding the cylinder, as shewn in Figures 5 and 8, and from thence through square passages j,j. Fig. 2 & 4, to the condensor, which is formed by the pedestals of the framework. The sliding valves e, e, are connected by rods h, h, to cranks at the ends of the vertical shaft i, i, which shaft, being driven round, works 25 the sliding valves to and fro, and produces the induction and eduction of the steam, which puts the piston in action, as above described. The shaft i is put in motion by means of a peculiarly formed cross or star-wheel k, fixed upon the shaft, as seen in Fig. 1,8,4,* 6. This cross or star-wheel has four grooves cut in it, in radial directions, at equal distances apart, which SO grooves are intended to receive the tappets that are to drive it round each one-fourth of a revolution; and between the grooves the periphery of the star-wheel is cut into as many concave segments, which are designed to work against the circular part of the rotary tappet wheel l, seen best in the horizontal view, Fig. 4. This tappet wheel consists of two segment plates; the 35 one fixed upon a vertical shaft to, the other adjustable thereon, and both are driven round by bevel gear above, connected to the rotatory horizontal shaft which works the air pump. Upon the tappet wheel segments there are two pins or tappets n, n, one of which at about every half revolution of the wheel strikes into one of the radial grooves o . >