Specification of Joseph Bramah : steam engines and boilers.

  • Bramah, Joseph.
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Specification of Joseph Bramah : steam engines and boilers. Source: Wellcome Collection.

    7/14 (page 5)
    Bramah's Improvements in the Construction of Steam Bngines and Boilers. tioned to tlie length and diameter of the steam pipe, which must necessarily lead from the station of this cone to the upper and lower extremities of the steam cylinder ; but in this instance the loss here mentioned will be entitled to a drawback when compared with other engines of all that portion of steam 5 which is constantly exhausted from the cavity, which at each end of the steam cylinder conveys the steam between the cylinder and the valves which perform the office of the cone in question. This double cone is of course composed of the same proper materials as the single ones, and the difference in construction is as follows :—Its length (if for an engine of equal size) must be twice that of 10 the latter or thereabouts, and in the middle of its length is cast a partition so as to cause it to represent two single cones joined together on one axis, and by this partition one becomes open at the larger end, and shut or solid at the lesser end, while the other is open at the smaller end and shut or solid at the larger. On this account, regard must always be had in determining the 1 5 diameter of the said cone, so as to have the mouth of the smaller end of dimen¬ sions sufficient either to convey the steam from the boiler to the cylinder, or from the cylinder to the condensing pipe, according to the way the cone may be applied. These cones being separated by the partition as above, constitute two cones as just mentioned, and in each of which is made exactly on the 20 sides opposite to each other an aperture just the same as in the single cone. This double cone is ground and fitted steam and air tight into an outer case, as in the former instance, and at each end of which is cast a flaunch, one for the reception of the end of the steam pipe, which pipe from its junction with the end of the said outer case completely encompasses the mouth of that end of the 25 cone presented to it so as to direct the steam into the cavity or interior part of the cone at that end where they meet; and I prefer in all instances the put¬ ting the small end of the cone towards the steam, and the larger towards the condensing pipe which communicated therewith in a similar manner as the former, with this difference only, that the condensing pipe must have a bend or 30 otherwise such a shape as will allow an air-tight stuffing box for the reception of the spindle or axis by which the cone is to be moved same as in the single cone. At opposite sides of this outer case are cut two apertures, each (four in all) of dimensions equal to those made in the cone within, and at such a distance, &c. from each other as will ensure the apertures in the cone to fall alternately 35 opposite to or in exact congruity with the former when the cone is turned round to opposite points, as in the instance of single ones ; these holes so cut or cast in the sides of the outer case as aforesaid are then inclosed or covered with a chamber or cap sufficiently spacious to receive the steam through the steam aperture, and also allow it to be discharged through the condensing aperture