Improvements relating to Furnaces.
Year: 1895

page_text: Date of Application, 24th May, 1895
Complete Specification Left, 24th Feb., 1896-Accepted, 28th Mar., 1896
Improvements relating to Furnaces.
I, HUGH MCPHAIL, of The Towers, Wakefield, Engineer, do hereby declare
the nature of this invention to be as follows:-
This invention relates to furnaces for raising steam or for any other purpose and
has for its objects the prevention of smoke and the obtainment of great economy in
the consumption of fuel.
According to my invention I abstract from the flue or flues at any suitable point
or points thereof a portion of the unburnt or partially burnt air or gases and pass the
same back into the furnace to be completely burnt therein. I may rely on the
natural draught of the furnace for drawing the aforesaid air or gases from the flue
or flues and for passing the same into the furnace again or I may employ for this
purpose a fan or other mechanical means.
When applying my invention to a steam boiler I provide a pipe, shaft or flue
forming a communication between the front end of the furnace or furnaces and
some convenient point or points in the flue or flues. It will usually be found
convenient to construct a special door frame or casting at the front of each furnace
to allow of the passage through it of the air or gases.
For this purpose
sometimes make the door frame or casting to project from the front end plate of
the boiler and I attach thereto either at the top or sides thereof, the pipe, flue or
shaft beforementioned. The said frame or casting is made with an internal
channel or chamber that communicates with the furnace space. The outlet or
outlets from said channel or chamber is or are preferably just above the level of
the dead plate but they may be at any other point.
In some instances the pipe or flue for conveying the air and gases to the furnace
may pass through the boiler, or through the internal flue or flues, and may be
delivered through the door frame as before stated, or through the grate along with
the air for supporting combustion or independently thereof.
Dated this 24th day of Mar 1895
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements relating to Furnaces.
I, HUGH MCPHAIL, of The Towers, Wakefield, Engineer, 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:-
This invention relates to steam generator and other furnaces and has for its
objects the prevention of smoke and the attainment of great economy in the
consumption of fuel.
According to my said invention I abstract from the furnace flue or flues at
any suitable point or points thereof a portion of the unburned or partially
burned air and gases and return the same to the furnace to be completely
burned therein.
I may rely on the natural draught of the furnace for drawing
Paino 11

page_text: such air and gases from the flue or flues and for passing the same into the furnace
again or I may employ for this purpose a fan or other mechanical means.
When applying my invention to a steam generator I provide a pipe, shaft or flue
forming a communication between the front end of the furnace or furnaces and
some convenient point or points in the external flue or flues.
In the accompanying drawings I have shown my invention applied to a two-flued
or Lancashire type of stationary boiler.
Figure 1 is a front elevation of the boiler and shows one side flue and half
of the bottom flue in transverse section.
Figure 2 is a sectional plan of a portion of the boiler and flues.
Figure 3 is a rear elevation of the doorfiame detached.
A is the boiler, B is the bottom flue, C, C are the side flues, D, D are pipes
open at both ends.
Each of the said pipes communicates at one end with the
aforesaid bottom flue and at the other end with one of the furnaces, the said pipe
being attached at this end to the door frame E of the furnace. Each pipe is
shown extending horizontally for some distance in the bottom flue towards the
rear end of the boiler, and it will be observed it is placed close to the bottom
of the boiler shell so that it will collect only the lighter products of combustion
and the unburned air which travels mostly along the top of the flue. In some
instances the pipes are provided with funnel shaped extremities.
I generally attach the pipe D or its equivalent shaft or flue to the front of
the door frame although in some instances I make the door frame project from the
front end plate of the boiler and I then attach the pipe D to the side of
the said frame. In lieu of a simple opening in the door frame of the furnace'
for the passage of the air and gases to be discharged directly into the furnace I
sometimes construct the said frame with an internal channel or chamber E¹
(Figure 3) into which the air and gases are discharged and from which they
pass into the furnace through suitable openings E' in the inner wall thereof.
The outlets E from said channel or chamber are preferably situated just above
the level of the dead plate but they may be at any other point.
In some instances the pipe or flue for conveying the air and gases to the furnace
passes through the boiler, or through the internal flue or flues, and is arranged to
deliver the air and gases through the door frame as before stated or through the
grate either along with the air for supporting combustion or independently
thereof.
Although I have shown the pipes D communicating with the bottom flue of the
boiler at points near the front end thereof they may communicate with such flue
at any other point or points thereof as may be desired, or they may be arranged
to communicate with the side flues.
It is obvious that these improvements can be equally well applied to Cornish,
and other types of boiler, and also to furnaces generally for the purpose of ensuring
greater economy in the consumption of fuel.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The combination with a furnace of means for abstracting partially consumed
air and gases from the flue or flues and returning them to the furnace substantially
as, and for the purposes, specified.
2. The improvements relating to furnaces substantially as described with
reference to the accompanying drawings, and for the purposes specified.
Dated this 24th day of February 1896
HASELTINE, LAKE & Co.,
45 Southampton Buildings, W.C., Agents for the Applicant.