RECENTLY PATENTED IMPROVEMENTS. 705 
parison, in principle, of this damper with an ordinary weighing-scales, its opera- 
tion will be readily understood. When the draft becomes too strong, by reason 
of unduly rapid combustion, the damper is raised, and the draft stopped, then 
upon the fire resuming its normal temperature, the damper opens, and allows 
the products of combustion free egress, until the closing velocity is again reached. 
The name of the inventor cannot be mentioned at this point. 
Improvements in Steam Boilers. — Mr. W. R. Kirk, of this city, has re- 
cently patented a steam pressure-boiler, the design of which is to enable tubular 
boilers to be easily and thoroughly cleaned and repaired, and it consists in taking 
a shell of a boiler of the usual form, the ends of the said shell are open, and 
within each is secured a ring, one of which has an external diameter considera- 
bly less than that of the opposite end. Fitted against and secured to the inner 
face of the smaller ring, is a head-plate which has such diameter as to permit its 
insertion through the larger ring. This head is secured in place by means of 
threaded bolts. A second head is in a like manner, fitted upon the outer face 
of the larger ring, this head has such increase of diameter over the smaller head 
as to adapt it to the larger opening to be closed. The two heads may receive 
any desired number of tubes and they are secured at their ends within said heads, 
and they are preferably placed in position after the heads are bolted to place. 
The joints between the heads and the rings are preferably formed by elastic 
gaskets, in order that they may be easily broken and reformed. When it is 
desired to cleanse or repair the boiler, the fastenings of the heads are removed, 
and the entire flue-section is withdrawn through the larger ring, after which each 
part of the boiler is easy of access and can be readily cleaned or repaired. There 
is also a very promising method of clearing the scales and sediment from fire-box 
boilers that has been patented by the same inventor, and to this end it consists, 
principally, in a steam-boiler composed of a shell and an enclosed fire-box which 
are separable and have their contiguous walls, secured in relative lateral position 
by means of sliding interlocking stay-bolts. There are provided at suitable points 
around the fire-box, rows of radial bolts or studs, the outer ends of these rows 
are united by means of a flat bar, thus causing it to form for each bolt, a "T"- 
shaped head. Secured upon the inner face of the fire box shell in a line, radially 
with each bar, is a bar that corresponds in transverse dimensions to like features 
of the first-mentioned bar, the grooves and bars are made slightly tapering length- 
wise, so that when the fire-box is being placed in position the bars will move 
easily until near the limit of their motion, and then when the fire-box is in posi- 
tion within the shell, said bars will closely fit into the said grooves so as to not 
only hold the parts rigidly in position, but also to prevent dirt and sediment from 
entering. The separation of this fire-box from its shell requires but little time, 
and by its operations the boiler may be made to last for many years. 
