Circular Flues or Furnaces for Steam Boilers.
Year: 1885

page_text: Circular Flues or Furnaces for Steam Boilers.
I DAVID PURVES of Ferro Dene, Green Lane, North Dulwich in the County of
Surrey, Engineer, do hereby declare the nature of my said invention for IMPROVE-
MENTS IN MACHINERY FOR ROLLING STRENGTHENING RINGS ON CIRCULAR FLUES OR
FURNACES FOR STEAM BOILERS to be as follows:--
Stiffening rings are in tin smith work rolled by a pair of rollers, one having a
circumferential convexity and the other a corresponding circumferential concavity.
My invention relates to an arrangement of mechanical parts and carriage
apparatus forming a convenient complete system for rolling strengthening rings
on boiler flues or furnaces.
To effect this I have introduced the following improvements. In the usual
application of these rollers one of the rollers have a permanently fixed axis and the
cylinder to be worked upon is wound radially in respect to the rollers as required.
With heavy boiler work it tends to expedition to have the flue maintained in
position about a fixed axis during the operation and to clear the rollers from the
rolled rings I make both rollers moveable. To permit of rolling rings at any
required place on a flue I make the support for the inner roller a strong hollow
bracket projecting horizantally sufficiently far from a strong head framing to admit
of more than half the length of the longest flue to be operated on.
In the centre of this projecting bracket or arm there is a shaft with a strong
crank disc and pin at the end of the bracket. The crank disc eccentric with the
shaft is supported in a bearing in the end of the bracket and a pin parallel with
the shaft and out of the centre is the crank on which the inner roller runs.
On the other end of the shaft a worm wheel is keyed and there is a worm and
hand wheel by which the shaft can be turned to move the centre of the inner roller
to follow up the formation of the strengthening ring.
The outer roller is carried on a counter balanced swing frame which can be fixed
in place for rolling by a cotter at one end.
When the rolling of the ring is completed the cotter is withdrawn and the
counter balance raises the roller free from the ring.

page_text: The outer roller is keyed upon a shaft aud driven by bevil wheel gear at the
head of the machine. To allow this shaft to rise at the roller end the bearing at
the gearing end is on trunion pins central with the axis of the bevil gear.
To bring the flue into position for the operation of rolling there is a special
carriage on rails. The flue lies thereon on guiding rollers which are raised
together by screws and levers to hold the flue in position while it is being rolled.
These screws and levers are parts of the carriage.
COMPLETE SPECIFICATION.
Improvements in Machinery for Rolling Strengthening Rings on
Circular Flues or Furnaces for Steam Boilers.
I DAVID PURVES of Ferro Dene Green Lane, North Dulwich in the county of
Surrey, Engineer, do hereby declare the nature of my said invention for IMPROVE-
MENTS IN MACHINERY FOR ROLLING STRENGTHENING RINGS ON CIRCULAR FLUES OR
FURNACES FOR STEAM BOILERS and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
My invention relates to an arrangement of mechanical parts and carriage
aparatus forming a convenient complete system for rolling strengthening rings
on boiler flues or furnaces.
To effect this I have introduced the following improvements. In the usual
application of these rollers one of the rollers has a permanently fixed axis and the
cylinder to be worked upon is wound radially in respect to the rollers as required.
With heavy boiler work it tends to expedition to have the flue maintained in
position about a fixed axis during the operation and to clear the rollers from the
rolled rings I make both rollers moveable. To permit of rolling rings at any
required place on a flue I make the support for the inner roller a strong hollow
bracket projecting horizontally, sufficiently far from a strong head framing to admit
of more than half the length of the largest flue to be operated on.
In the centre of this projecting bracket or arm there is a shaft with a strong
crank disc and pin at the end of the bracket.
The crank disc eccentric with the shaft is supported by a bearing in the end of
the bracket and a pin parallel with the shaft and out of the centre is the crank on
which the inner roller runs,

page_text: On the other end of the shaft a worm wheel is keyed and there is a worm and
hand wheel by which the shaft can be turned to move the centre of the inner roller
to follow up the formation of the strengthening ring.
The outer roller is carried on a counterbalanced swing frame which can be fixed
in place for rolling by a cotter at one end.
When the rolling of the ring is completed the cotter is withdrawn and the
counterbalance raises the roller free from the ring.
The outer roller is keyed on a shaft and driven by bevil wheel gear at the head
of the machine. To allow this shaft to rise at the roller end the bearing at the
gearing end is on trunion pins central with axis of the bevil gear.
To bring the flue into position for the operation of rolling there is a special
carriage on rails. The flue lies thereon on guiding rollers which are raised together
by screws and levers to hold the flue in position while it is being rolled. These
screws and levers are parts of the carriage.
Having fully described the nature of my invention I shall now particularly
describe the mechanical combination by which according to this invention
strengthening rings are rolled on flues for steam boilers.
In figures 1. 2. 3. I shew the machine as adapted for rolling separate rings on
flues. My invention does not relate to the arrangement of these strengthening
corrugations on the flue, but only to the machine for forming such corrugations.
By the worm wheel A, and its worm, the shaft A is rotated to elevated or to
depress the eccentric pin A, to bring the loose corrugating roller A into position
either for corrugating or to clear the flue.
By the bevil gear B₁ the shaft B is turned carrying the fixed corrugated roller B,
the shaft B is supported in the trunion bearing B, and in bearings on the counter-
weight lever B, B. The counterweight lever is hinged on bearings Be Be in the
brackets B, Br. These bearings B₁ B have clearance on the underside to allow of
the elevation of the roller B, without binding.
Between the brackets B, B, there is a distance piece B, with a slot B, admitting
of the required elevation of the counterweight lever which is held down when
required by the moveable cotter B10-
The carriage C is shewn as adapted for the formation of separate strengthening
rings, the lifting screws C₁ elevate the lifting bar C, and the levers C, with their
rollers C. These rollers have to be spaced to clear the corrugations.
The flue D is shewn in place on the carriage.
The bracket arm E is a strong projecting support for the corrugating roller.
This bracket must project at least half the length of the flue but it will generally
be better to make it strong enough and to project to and take in the furthest
corrugation of the flue.
When the corrugation is to be wholly one spiral the carriage and flue are set
horizontally oblique to the shaft A.
To admit of greater obliquity the bracket can be formed with the shaft A nearer
to one side than the other. A. stationary carriage will then take the place of C and
another length of carriage on wheels as C will run up to butt the stationary
carriage making together a bed about twice the length of that shewn.
rollers C, will then be on a separate axles inclined to be all normal to the direction
of the spiral
The
When the corrugation is to be a spiral the inner roller A must be slightly convex
longitudinally on the body to correspond with the oblique section of the furnace.
The outer roller may be similarly concave longitudinally.
The carriage is stationary while the corrugations are being formed.
Having set forth how the rolling of strengthening rings can be accomplished on
flues for steam boilers I state that there are obvious mechanical equivelents for
many of the details some of which may be adopted without departing from the
substance of my invention and that corrugations have been rolled on cylinders
nade of thin plates by other machines not adapted to the heavy work of steam
boilers.

page_text: I declare that what I claim as the improvements constituting my invention as
parts of a machine for corrugating the flues for steam boilers are:-
First. The eccentric shaft A A with a mechanical feed.
Second. The counterweight roller lever B B.
Third. The trunion bearing for the shaft C, C.
Fourth. A carriage upon which the flue can be transported from the heating
furnace fitted with a roller bed on which the furnace revolves while being
corrugated.
Fifth. The general arrangement of mechanical parts described as a machine for
forming corrugations on flues of steam boilers.
All substantially as described and for the purposes set forth; or their mechanical
equivelents.
DAVID PURVES.