Improvements in Furnace Draught Indicators.
Year: 1897

page_text: Date of Application, 16th July, 1897-Accepted, 21st Aug., 1897
COMPLETE SPECIFICATION.
Improvements in Furnace Draught Indicators.
I, MAX CLEMENS KILLIG of Königbrückerstrasse, Dresden, Germany, Merchant, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The furnace draught indicator of this invention, as distinguished from the
acrometers hitherto employed for a like purpose, is provided with an air vane which
stands perpendicularly when in the state of rest position and is balanced by means of
an adjustable counter-weight, in consequence of which the instrument may be
rendered extremely sensitive, and is further provided with an adjustable slide for
regulating the admission of air to its casing.
In the accompanying drawings Fig. 1 is an elevation of the draught indicator of
this invention with the division plate or scale omitted for greater clearness of
illustration. Fig. 2 is a back view of the same. Figs. 3 to 6 are views of details.
Figs. 7 and 8 are respectively an elevation and a sectional view of a modification.
is a weighted arm by which an air vane f is balanced. This arm may be applied
to the axis a either within the casing g as shewn in Figs. 1 and 3 or outside the casing
as in Figs. 2 and 6 so that in this latter case the adjustment may at any time be
effected from the outside. To this end the arm is preforably screw threaded and
the weight w correspondingly screwed like a nut to permit it, for the purpose of
balancing the air vane f, to be worked up and down on the arm, but the arm might
be made plain and the weight slid over it and fixed by a set screw.
Preferably the air vane is serrated or notched (Figs. 3, 6,) on its upper edge which
comes close to the inner circumference of the casing, said serrations having for
object to permit at that part the passage of some air, and thus, by reason of the
friction thereby occasioned against the edges of the serrations, to facilitate the
movement of the air vane.
o is an opening provided in the back of the casing g for the admission of air and in
front of which a screen or fine sieve may be placed to protect it against dust which
otherwise might be carried into the casing.
c is a slide arranged in front of the opening o for regulating the admission of air.
It is preferably in the form of a snooth plate furnished with a slot i through which
and into the back of the casing takes a fixing screw u having a milled head k
(Figs. 2, 4, 5). By means of this screw the opening o may be laid full open (Fig. 2)
or the slide adjusted to more or less close it (Figs. 4, 5).
In applying the draught indicator to a steam boiler furnace it is fixed in front of
the boiler and placed in communication with the smoke flue through the outlet s and
a connecting tube.
In order that the stoker may be properly guided in the management of the furnace
a trial should be made on a calm day with respect to the force of draught required to
be maintained for the desired steam pressure, and when this minimum draught has
been ascertained, the position of the pointer 2, which is fixed on the axis a, is so
adjusted by displacing the weight and the slide c that said pointer occupies a
certain initial position which the stoker is to regard as the normal position in the

page_text: future. Should the weather become more windy the air will the more quickly pass
through the aperature o in the casing and thereby. the air vane f and with it the
pointer z will be turned from the normal position, the latter then pointing to a
higher number on the scale (not shewn). The stoker has then to close the damper
so far as will cause the pointer z to again také its normal position corresponding to
the now diminished but suitable draught.
In order, if desired, to do away with the dead space formed by the quarter circle
recess d in the part d' of the casing, in which recess the air vane f moves, this latter
may be made shorter and the quarter circle recess closed by a cover b (Figs. 7, 8)
provided with a slot t for the free passage and play of an arm m to which the air
vane is attached.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is
:
A draught indicator or draught gauge for furnaces in which an upwardly extending
air vanef is balanced or adapted to be balanced by means of an adjustable counter-
weight and in which a slide c is arranged in front of an air opening o for regulating.
the admission of air into the casing g, substantially as described and shewn."
Dated this 16th day of July 1897.
THOMAS R. SHILLITO,.
89 Chancery Lane, London, W.C., Agent for the Applicant.
THOMAS R. SHILLITO,.
89 Chancery Lane, London, W.C., Agent for the Applicant.