Dampers of Steam-boiler Furnaces.
Year: 1887

page_text: Dampers of Steam-boiler Furnaces.
We, DAVID PARSONS, DAVID JOHN PARSONS, JOSEPH HENRY PARSONS and
SAMUEL JESSE PARSONS, all trading together as David Parsons & Sons, of Corbyns
Hall Iron Works, Pensnett, near Dudley, Staffordshire, Engineers and Ironfounders,
do hereby declare the nature of this invention to be as follows:-
This invention has reference to improvements in apparatus for automatically con-
trolling the dampers of steam-boiler furnaces by the pressure of the steam in the boiler
or pipes which apparatus automatically closes the damper or dampers on the steam
rising above its proper working pressure, and opens the damper or dampers on the
steam pressure falling and maintains it or them in that position.
We will describe our invention in the form of an apparatus for controlling for
instance a steam-boiler damper which is arranged to work in a vertical direction. We
provide a fixed vertical steam cylinder containing a piston having a piston rod working
through a stuffing-box in the cylinder cover. This piston rod is connected to the
damper by a chain or wire rope passing over a suitable guide pulley so that when the
damper is open the piston is near the bottom of the cylinder and when the damper is
closed the piston is near the top of the cylinder. The damper is counterbalanced so
that it is slightly the heavier and will fall and close when the pressure on each side of
the piston is equal. Live steam from the boiler is admitted to the cylinder above the
piston the steam inlet to the cylinder being opened or closed by a suitable balanced
slide valve, preferably a piston valve. By moving this slide valve in one direction
steam enters the cylinder and depresses the piston and opens the damper, and on
moving the slide valve in the opposite direction the steam inlet is cut off and an
exhaust port opened to allow the steam in the cylinder to escape and the damper to
close. This slide valve is automatically controlled by the pressure of the steam acting
upon a column of mercury as follows:
―
Near the steam cylinder is a closed vessel containing mercury and having an inlet
opening above the level of the mercury through which live steam is admitted from the
boiler. From this vessel rises a small vertical tube about equal in length to the height
of the column of mercury corresponding with the working pressure of steam in the

page_text: boiler. This tube opens out at the top above the mean level of the mercury into a
chamber containing a float which is connected to the slide valve of the steam cylinder
by suitable rods and levers or by a chain running over guide pulleys.
When the steam in the boiler does not exceed its proper working pressure, cor-
responding with the height of the mercury column, the said float rests upon the bottom
of the chamber and through its said connections with the slide valve maintains the
slide valve open and allows steam to enter the cylinder to keep the piston at its lowest
position and the damper open. Directly the steam in the boiler rises above its proper
working pressure, the mercury column is by the steam caused to rise and to carry
with it the float which latter in rising moves the slide valve and closes the steam inlet
to the cylinder and opens the exhaust through which the steam contained in the
cylinder escapes thus allowing the damper which is now the heavier, to gradually close
and raise the piston. On the steam in the boiler falling again to the proper working
pressure the mercury and float correspondingly fall and cause the slide valve to close
the exhaust outlet and to open the steam inlet to the cylinder when the piston will
move to its lowest position again and in so doing open the damper.
On first lighting the boiler furnace the damper has to be raised by hand and main-
tained open by a hook in the damper chain or by other means until sufficient steam
has been generated in the boiler to act upon the piston to maintain the damper open.
The said apparatus may either be arranged to control a single damper as above
described or a single apparatus may control several dampers as for instance in a range
of steam-boilers. In this latter case for instance the chain or rope from the piston rod
may be connected to a pulley fixed upon a rocking shaft on which shaft also are fixed
the chain pulleys of the various dampers so that the dampers will all be opened together
by the steam acting upon the piston and turning the rocking shaft in one direction and
all closed together when the steam has been caused to escape from the cylinder as
above described.
When the apparatus is arranged for a range of boilers and the cylinder and the
vessel containing the mercury receive their steam from the main steam pipe, we some-
times find it necessary to continue a tube from the mercury column above the said
chamber so that if the pressure in the steam main should rise very considerably above
proper working pressure (as would be the case if the steam from one of the boilers
working at a higher pressure than the others were suddenly turned into the main) the
mercury can rise up the said continuation of the tube and prevent the chamber bursting
as it otherwise might do.
the
We sometimes find it necessary to provide a spring cushion in the cylinder which
acts as a buffer and brings the piston to rest gradually at the end of its stroke after it
has been moved by the steam.
The steam cylinder may be arranged horizontally instead of vertically and instead
of being single acting as above described it may be double acting, the slide valve being
operated by the column of mercury, as above described, and arranged so as to admit
steam either at one or the other side of the piston similarly to an ordinary steam
engine cylinder. A double acting cylinder is more particularly useful when the
damper moves horizontally and the circumstances will not permit of a counterweight
being used.
Instead of operating the piston and the column of mercury by steam as above
described, compressed air may be used and this arrangement applies very conveniently
when the boilers are supplying steam for a blast engine, the steam cylinder and the
vessel containing the mercury being connected to receive compressed air from the
blast main. In this and similar cases where the blast or pressure of air available is
comparatively small we sometimes use water or some lighter liquid than mercury in
place of the mercury.
Tt1: 59 1
1
1001

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Automatically Controlling the
Dampers of Steam Boiler Furnaces.
We, DAVID PARSONS, DAVID JOHN PARSONS, JOSEPH HENRY PARSONS and
SAMUEL JESSE PARSONS, all trading together as David Parsons & Sons, of Corbyns Hall
Iron Works, Pensnett, near Dudley, Staffordshire, Engineers and Ironfounders, do
hereby declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following statement:-
This invention has reference to improvements in apparatus for automatically con-
trolling the dampers of steam-boiler furnaces by the pressure of the steam in the boiler
or pipes which apparatus automatically closes the damper or dampers on the steam
rising above its proper working pressure, and opens the damper or dampers on the
steam pressure falling and maintains it or them in that position.
We will describe our invention in the form of an apparatus for controlling lor
instance a steam-boiler damper which is arranged to work in a vertical direction. We
provide a fixed vertical steam cylinder containing a piston having a piston rod
working through a stuffing-box in the cylinder cover. This piston rod is connected
to the damper by a chain or wire rope passing over a suitable guide pulley so that when
the damper is open the piston is near the bottom of the cylinder and when the damper
is closed the piston is near the top of the cylinder. The damper is counterbalanced so
that it is slightly the heavier and will fall and close when the pressure on each side of
the piston is equal. Live steam from the boiler is admitted to the cylinder above the
piston the steam inlet to the cylinder being opened or closed by a suitable balanced
slide valve, preferably a piston valve. By moving this slide valve in one direction
steam enters the cylinder and depresses the piston and opens the damper, and on
moving the slide valve in the opposite direction the steam inlet is cut off and an
exhaust port opened to allow the steam in the cylinder to escape and the damper to
close. This slide valve is automatically controlled by the pressure of the steam
acting upon a column of mercury as follows:-
Near the steam cylinder is a closed vessel containing mercury and having an inlet
opening above the level of the mercury through which live steam is admitted from the
boiler. From this vessel rises a small vertical tube about equal in length to the
height of the column of mercury corresponding with the working pressure of steam
in the boiler. This tube opens out at the top above the mean level of the mercury
into a chamber containing a float which is connected to the slide valve of the steam
cylinder by suitable rods and levers or by a chain running over guide pulleys.
When the steam in the boiler does not exceed its proper working pressure, corre-
sponding with the height of the mercury column, the said float rests upon the hottoin
of the chamber and through its said connections with the slide valve maintains the

page_text: slide valve open and allows steam to enter the cylinder to keep the piston at its lowest
position and the damper open. Directly the steam in the boiler rises above its proper
working pressure, the mercury column is by the steam caused to rise and to carry
with it the float which latter in rising moves the slide valve and closes the steam inlet
to the cylinder and opens the exhaust through which the steam contained in the
cylinder escapes thus allowing the damper which is now the heavier, to gradually
close and raise the piston. On the steam in the boiler falling again to the proper
working pressure the mercury and float correspondingly fall and cause the slide valve
to close the exhaust outlet and to open the steam iniet to the cylinder when the piston
will move to its lowest position again and in so doing open the damper.
On first lighting the boiler furnace the damper has to be raised by hand and
maintained open by a hook in the damper chain or by other means until sufficient
steam has been generated in the boiler to act upon the piston to maintain the damper
open.
The said apparatus may either be arranged to control a single damper as above
described or a single apparatus may control several dampers as for instance in a range
of steam-boilers. In this latter case for instance the chain or rope from the piston
rod may be connected to a pulley fixed upon a rocking shaft on which shaft also are
fixed the chain pulleys of the various dampers so that the dampers will all be opened
together by the steam acting upon the piston and turning the rocking shaft in one
direction and all closed together when the steam has been caused to escape from the
cylinder as above described.
When the apparatus is arranged for a range of boilers and the cylinder and the
vessel containing the mercury receive their steam from the main steam pipe, we some-
times find it necessary to continue a tube from the mercury column above the said
chamber so that if the pressure in the steam main should rise very considerably above
the proper working pressure (as would be the case if the steam from one of the boilers
working at a higher pressure than the others were suddenly turned into the main) the
mercury can rise in the said continuation of the tube and prevent the chamber bursting
as it otherwise might do.
We sometimes find it necessary to provide a spring cushion in the cylinder which
acts as a buffer and brings the piston to rest gradually at the end of its stroke after it
has been moved by the steam.
On the accompanying drawings Fig. 1 represents in sectional side elevation and
Fig. 2 in front elevation an apparatus for automatically controlling the damper of a
steam boiler furnace constructed according to this invention and Figs. 3 and 4
represent details of parts of the same on an enlarged scale.
The same letters of reference indicate corresponding parts in all the Figures of the
drawings.
a is the steam cylinder containing the piston band having the piston rod c working
through a stuffing box in the cylinder cover. The upper end of the piston rod b is
connected by the wire rope or chain d to the pulley e which is fixed on the wayshaft f
on which is also fixed the pulley g over which the chain passes the damper i
is suspended at one end of the chain h and the balance weight at the other end.
The weight of the damper is only partly counterbalanced so that if unsupported the
damper would descend and close the flue. is the balanced slide valve (in the
arrangement illustrated an ordinary double piston valve is used but we do not
confine ourselves to any particular kind of valve or valves) which regulates the
admission of steam to the cylinder a and its exhaust therefrom and which works in the
cylindrical casing provided with the steam inlet m leading from the boiler or boilers.
is the steam inlet and outlet orifice of the cylinder a, and o is the exhaust pipe, which
is also connected at of to the lower part of the cylinder below the piston 6 so that the
underside of the piston is always open to the atmosphere. p is the closed vessel
which contains mercury and p² is the pipe which admits live steam thereto from the
boiler or boilers. 7 is the pipe of small bore up which the mercury is forced by the
steam and which is about equal in length to the height of the column of mercury
corresponding with the working pressure of steam in the boiler or boilers. The pipe

page_text: p.
is screwed into a plug which is screwed into the top of the vessel p and the lower
end of the pipe reaches almost to the bottom of the vessel
A small hole q is pro-
vided through which the mercury can be poured into the vessel and which is closed
by a screw. is the chamber in which the top of the tube 7 opens and which is
supported by the standards and contains the float t which passes through the cover and is
counterbalanced by the counterweight connected thereto by the chain 3 passing
over the guide pulley . Motion is transmitted from the float to the valve by the
rod u and lever the rod being adjustably connected to the cross piece (which
latter is secured to the float and guided by the pin t) and jointed to the free end of the
lever to which also the valve kis jointed at u³.
18
The operation of the parts above described is as follows:-When the steam in the
boiler or boilers to which the inlet m is connected does not exceed its proper working
pressure, corresponding with the height of the mercury column in the pipe 7, the float t
rests upon the bottom of the chamber (see Fig. 3) and through the rod and lever u
maintains the slide valve open so that steam can pass through the pipe m into the
valve casing and through the holes and orifice n into the cylinder above the piston
which is by the steam maintained near the bottom of the cylinder and the damper i
open as shewn by our drawings. On the steam in the boiler rising above its proper
working pressure the steam acting upon the mercury in the vessel p causes it to rise
in the pipe 7 into the chamber carrying the float upwards which latter raises the
valve which stops the supply of steam to the cylinder a by closing the steam inlet
holes, and allows the steam in the cylinder a to escape into the exhaust pipe o by the
valve krising far enough to open the holes ³. The damper i now gradually descends
and raises the piston band counterweight j. On the steam in the boiler or boilers
falling again to its proper working pressure the mercury in the pipe q and the float
correspondingly fall and cause the valve k to move downwardly and to close the
exhaust outlets 3 and open the steam inlet holes so as to admit steain into the cylinder a
which will depress the piston and raise the damper.
The apparatus above described and illustrated by the accompanying drawings can
readily be applied for controlling several dampers as in a range of steam boilers by
extending the way shaft and suspending each of the dampers therefrom by a chain h
and counterweight so that the dampers will all open or close together by the steam
acting upon the piston & as above described.
is the small pipe which is connected to and carried above the chamber r and is by.
preference led downwardly to a vessel which is connected by a small pipe to the
vessel p. Should the steam suddenly rise very considerably above its normal pressure
the mercury would rise in the pipe and pass down into the vessel ², from whence
by opening a small cock in the pipe it can be allowed to run back into the
vessel p.
w is a pad of lead in the bottom of the cylinder a for the piston b to strike
upon if it should descend too quickly.
The steam cylinder may be arranged horizontally instead of vertically and instead
of being single acting as above described, it may be double acting, the slide valve
being operated by the column of mercury, as above described, and arranged so as to
admit steam either at one or the other side of the piston similarly to an ordinary steam
engine cylinder. A doable acting cylinder is more particularly useful when the
damper moves horizontally and the circumstances will not permit of a counterweight
being used.
Instead of operating the piston and the column of mercury by steam as above des-
cribed, compressed air may be used and this arrangement applies very conveniently
when the boilers are supplying steam for a blast engine the steam cylinder and the
vessel containing the mercury being connected to receive compressed air from the
blast main. In this and similar cases where the blast or pressure of air available is
comparatively small we sometimes use water or some lighter liquid than mercury in
place of the mercury.
We wish it to be understood that we do not limit ourselves to the details herein
described and illustrated by the accompanying drawings as it is evident the same may
be varied in many ways without departing from the nature of our invention.

page_text: Having now particularly described and ascertained the nature of our said Inven-
tion, and in what manner the same is to be performed, we declare that what we claim
15:
1st. The employment, with a steam cylinder and piston for actuating the damper or
dampers of steam-boiler furnaces, of a column of mercury or other fluid which is acted
upon by steam from the boiler or boilers and arranged to operate the valve or valves
for admitting steam to the said steam cylinder or allowing steam to escape therefrom
so that the opening or closing of the damper is dependent upon the height of the said
column of mercury or other fluid, substantially as described.
2nd. An apparatus for automatically controlling the dampers of steam-boiler
furnaces arranged and operating substantially as hereinbefore described and illustrated
by the accompanying drawings.
Dated this 50th low of Lune 1998
CHARLES BOSWORTH KETLEY,
Agent for the Applicants.