IMPROVE- MENTS IN BLOW-OFF APPARATUS FOR STEAM BOILERS
Year: 1880

page_text: LETTERS PATENT to Stephen Watkins, of 5, High Street, Wolverhampton, in
the County of Stafford, Consulting Engineer, for an Invention of "IMPROVE-
MENTS IN BLOW-OFF APPARATUS FOR STEAM BOILERS."
PROVISIONAL SPECIFICATION left by the said Stephen Watkins at the
Office of the Commissioners of Patents on the 12th August 1880.
STEPHEN WATKINS, of 5, High Street, Wolverhampton, in the County of Stafford,
Consulting Engineer. "IMPROVEMENTS IN BLOW-OFF APPARATUS FOR STEAM
BOILERS,'
This Invention relates to improved blow-off apparatus for preventing serious
leakage through a defective blow-off cock or valve, the said apparatus also
answering the double purpose of blowing out the dirty water from the bottom of
the boiler and the scum from the upper stratum.
In the case of a boiler which has the blow-off cock fixed below, I carry a stand pipo
within the boiler from the bottom thereof to, or about to, the low water level. The
said stand pipe is joined at the blow-off outlet from the boiler by means of a faced
or other permanent joint, so that it is impossible for any water to pass into the
blow-off pipes except by first passing down the stand pipe. A pipe of larger
diameter (hereinafter called the "hood"-pipe), with the lower end open and the
upper end closed, is suspended within the boiler so as to be capable of being lowered
down over the stand pipe or raised, as desired. A hollow mounting is fixed upon
the top of the boiler to receive the upper end of the hood pipe, when the hood pipe
is raised fully up with the bottom of it and clear of the top of the stand pipes.
When the hood pipe is raised up the scum water only can be blown out through
the stand pipe and blow off cock, and it is impossible for the water to leak down
through the blow-off cock below the top of the stand pipe; but when it is desired
to blow out the bottom water the hood pipe is lowered, upon which the water
rushes up between the inside of the hood pipe and the outside of the stand pipe to
the top of the latter, whence it rushes down the inside thereof and so out through
the blow-off cock. When it is desired to empty the boiler cold the water can be
syphoned out by keeping the hood pipe down. The hood pipe may be raised and
lowered by means of a quick threaded screw passing through a nut fixed in the top

page_text: of the hood pipe, the upper part of the rod on which the screw is formed passing
out through a packing box on the top of the hollow mounting aforesaid, and having
a handle fixed to the top thereof; or the hood pipe may be raised and lowered in
any convenient manner. Guides between the stand pipe and hood pipe, or
equivalent arrangements, are used to prevent the latter pipe from being turned
when the screw arrangement is used for raising it, and to guide the hood pipe over
the stand pipe when raised above it. Roughly pointed or other shaped projections
may be cast or otherwise fixed inside the hood pipe so as as to break up any scale
which may form upon the stand pipe.
In the case of a double flued Cornish or Lancashire boiler the stand pipe is
placed between the flues; in the case of a single flued boiler the stand pipe may
be fixed to pass up through a vertical cross tube.
To facilitate the blowing out of the scum a saucer, or trough, or other suitable
shaped vessel, may be suspended or carried around the top of the stand pipe, but so
as to leave an annular opening for the passage of the hood pipe between the said
vessel and the stand pipe.
When the blow-off cock is fixed above the boiler, an inner pipe (hereinafter
called the hanging pipe, and corresponding to the stand pipe aforesaid), passes
from a blow-off outlet at the top of a hollow mounting on the boiler down to, or
about low water level, and an outer pipe (corresponding to the hood pipe aforesaid)
has its lower end open and its upper end provided with a packing box to slide on
the hanging pipe. As in the former case, the scum is blown off when the outer
pipe is up, and the bottom water when it is down. The outer pipe may be raised
by means of a quick threaded screw, passing through a nut in a lug on the side of
the pipe, or by any suitable means. Similar vessels for facilitating the blowing out
of the scum may be used to those before referred to.
Instead of the apparatus before described, a movable pipe may be connected by
means of a swivel or trunnion joint to the top of the stand pipe or bottom of the
hanging pipe, as the case may be. The movable pipe may be balanced by means of
a weight attached to a part of the pipe which may be produced for the purpose
beyond the fulcrum. The outer end of the movable pipe is raised for blowing off
the scum, and lowered for blowing out the bottom water. The raising and
lowering may be effected by means of a rod passing through a packing box on the
boiler top. For blowing off the scum the end of the pipe may be pulled up into
the bottom of a trough, or other suitable shaped vessel to receive the scum. The
stand pipe or hanging pipe may be bent sideways so as to bring the movable pipe
into the middle of the boiler, or the movable pipe itself may be bent.
In the first and second arrangement of pipes, as above described, by keeping the
inner pipe sufficiently high, the scum water can be blown out at any level,
accordingly as the outer pipe is lowered; and the scum water can obviously be
blown out at any level by the thired arrangement; and by either arrangement the
level of the scum can be followed down.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Stephen Watkins in the Great Seal Patent Office on the 11th
February 1881.
STEPHEN WATKINS, of 5, High Street, Wolverhampton, in the County of Stafford,
Consulting Engineer. "IMPROVEMENTS IN BLOW-OFF APPARATUS FOR STEAM
BOILERS.
This Invention relates to improved blow-off apparatus for preventing serious
leakage through a defective blow-off cock or valve, the said apparatus also
answering the double purpose of blowing out dirty water from the bottom of the
boiler and scum from the upper stratum.
"
In the case of a boiler which has the blow-off cock fixed below, I carry a stand-
pipe within the boiler from the bottom thereof to the low-water level. The said
pipe is joined at the blow-off outlet from the boiler by means of a faced or other
permanent joint, so that it is impossible for any water to pass into the blow-off
pipes except by first passing down the stand-pipe. A pipe of larger diameter
(hereinafter called the "hood-pipe") with the lower end open and the upper end
closed is suspended within the boiler, so as to be capable of being lowered down
over the stand pipe or raised, as desired. A. hollow mounting is fixed upon the top
of the boiler to receive the upper end of the "hood-pipe," when the "hood-pipe
is raised fully up with the bottom of it clear of the top of the stand-pipe. When
the "hood-pipe" is raised up the scum water only can be blown out through the
stand-pipe and blow-off cock, and it is impossible for the water to leak down
through the blow-off cock below the top of the stand-pipe; but when it is desired
to blow out water from the bottom of the boiler the "hood-pipe" is lowered, upon
which the water rushes up between the inside of the "hood-pipe" and the outside
of the stand-pipe to the top of the latter, whence it rushes down the inside thereof
and so out through the blow-off cock. When it is desired to empty the boiler cold
the man-lid may be removed, or a cock or valve opened to allow of the ingress of
air above the water line, when the water can be syphoned out by keeping the
hood-pipe" down. The "hood-pipe may be raised and lowered in any convenient
manner.
To facilitate the blowing out of the scum a saucer, or trough, or other suitably
shaped vessel, may be suspended or carried around the top of the stand-pipe, but
so as to leave an annular opening for the passage of the "hood-pipe" between the
said vessel and the stand-pipe.
When the blow-off cock is fixed above the boiler an inner pipe (hereinafter called
the "hanging-pipe," and corresponding to the stand-pipe aforesaid) passes from a
blow-off outlet at the top of a hollow mounting on the boiler down to low water
level, and an outer pipe (hereinafter called the "sleeve-pipe," and corresponding
to the "hood-pipe aforesaid) has its lower end open, and its upper end provided
with a packing-box to slide on the "hanging-pipe." As in the former case scuin
is blown off when the outer pipe is up and the blow-off cock open, and water from
the bottom of the boiler when it is down and the blow-off cock open. The sleeve-
pipe may be raised and lowered by any suitable means.
Instead of either apparatus before described a movable pipe may be connected
by means of a swivel or trunnion joint to the top of the stand-pipe or bottom of
the "hanging-pipe, as the case may be. The movable pipe may be balanced by
means of a weight attached to a part of the pipe produced for the purpose beyond
the fulcrum. The outer end of the movable pipe is raised for blowing off the scum,
and lowered for blowing out water from the bottom of the boiler. The movable
pipe may be raised and lowered by any suitable means. The stand-pipe or " hanging-
pipe" may be bent sideways, so as to bring the movable pipe into the middle of the
boiler, or the movable pipe itself, or both of the pipes may be bent.

page_text: Having thus stated the nature of my said Invention I will now proceed to more
particularly describe and ascertain the manner of performing the same with
reference to the accompanying Drawings and the letters of reference marked
thereon.
The "hood-pipe" arrangement of my Invention is illustrated by Figures 1 to 4
(Sheet 1); Figure 1 is a transverse section through a double-flued Cornish boiler,
shewing this modification of my Invention also in cross section. This section is
taken on line x, x, of Figure 2, which latter is a section (but with the upper part
in elevation, and the "hood-pipe" shewn down instead of up) taken on line y, y,
of Figure 1. A is the stand-pipe fixed to the stool B by means of a faced joint;
C is the "hood-pipe;" D, a hollow mounting fixed on the top of the boiler to
receive the upper end of the "hood-pipe. The "hood-pipe" is shewn to be raised
and lowered by means of a quick-threaded screwed rod a rotated by the wheel and
handle b. The upper end of the screwed rod is plain and passes through a packing-
box C, but is provided with a collar within the packing-box, as shewn, resting upon
the bush in the bottom of the packing-box. The part where the screwed rod a
passes through the top of the "hood-pipe" C is screwed to receive the rod; the
screwed part consisting preferably of a gun-metal bush held in by means of a set
screw or otherwise. Figure 3 is an enlarged section, shewing the bottom of the
pipe C and the top of the pipe A in the same relative position as they are shewn in
Figure 1; Figure 4 is a section taken on line ¹, x, of Figure 3; d, d, are pro-
jections at the bottom of the pipe C, so as to form a stop when the pipe C is
screwed down, and thus leave an aperture between the bottom of the pipe and the
inside of the bottom of the boiler. The said projections d, d, also carry the lower
part of the V-pieces e, e, which extend for a short distance up the inside of the
pipe C; ff, are V-guides extending down each side of the pipe A and act as
guides to the V-pieces e, e, and thus prevent the pipe C from being turned as it is
screwed up or down. Of course provision must be made in the bottom stool B to
allow the V-guides f, f, to pass therethrough when placing the pipe A in position.
In Figure 1 the pipe C is shewn raised up above the pipe A, and in such position
of course only water above the low-level height can be blown off when the cock E
(Figure 2) is open, and the water cannot run down lower than low-water level
through the pipe A, however badly the cock E may leak, nor even if it is left open.
In Figure 2 the pipe C is shewn screwed down, in which case only water from the
bottom of the boiler can be blown out when the cock E is open, the water rushing
under the bottom of the pipe C, as shewn by the arrows, thence up between the
walls of the pipe C and the pipe A, over the top of the pipe A, and down the inside
of the pipe A. The pipe C is screwed down only at such times as it is desired to
blow out water from the bottom of the boiler. It remains screwed up above low-
water level at all other times, and especially when left for the night, thus absolutely
preventing any possibility of the water leaking down below low-water level on
account of any defect in the blow-off cock. When it is desired to empty the
boiler cold the "hood-pipe" is screwed down the same as for blowing-off, when the
water will syphon out. It will also syphon out at a tolerably high temperature (at
180 degrees Fahrenheit, and even upwards) depending somewhat on the height of
the fall through the blow-off pipes. When however it is desired to syphon out the
water it is a wise precaution to screw down the "hood-pipe" immediately after
the fires are drawn, in which case the "hood-pipe" and stand-pipe will be full of
water when the cock is opened for syphoning out, and the man-lid should be taken
off or other aperture opened into the boiler to allow the ingress of air as the water
is syphoned off.
In applying this arrangement to a single-flued boiler, a vertical "Galloway" or
other vertical cross-tube must be fixed in the internal flue, and of sufficient diameter
to allow the pipes C and A to pass through it. Of course in such a case the
arrangement must be fixed somewhat beyond the fire bridge.
The stand-pipe A may rise to any desired level above the low-water level, the
lengths of the pipe C and hollow mounting D being altered to correspond, in which

page_text: case scum water may be blown off from any desired level of stratum, accordingly
as the "hood-pipe" is lowered down.
In Figures 1 and 2 an arrangement of scum troughs is shown in connection with
the stand-pipe and "hood-pipe." F, F, etc., are the troughs extending across the
boiler and resting on the flues, and extending also lengthways of the boiler at each
side for any desired extent. Of course, if the parts lengthways of the boiler
extend for any considerable length, their ends must be supported by a bar resting
across the tubes, or by any convenient method. Perforations are shewn in the
troughs. The part G, which is cylindrical, allows of the passage of the pipe C, and
also prevents water from the upper stratum from entering the pipe A, except
through the troughs F, F, etc. The troughs F, F, etc., are covered over at the
parts H, H, so as to prevent too great a rush of water at those points, and thus
interfere with the distribution of the flow. The "hood-pipe" arrangement may be
used with or without the troughs. The part G should be carried up to high water
level, and the scumming troughs may be placed at any desired level; probably two
or three inches under high-water level for the top of the troughs would be the best
level for ordinary purposes, but as the employment of scumming troughs is not
novel, persons having experience in their use will know the proper level to fix
them to suit the circumstances under which they are required. Pipes or any other
suitably shaped vessels may, of course, be used in the place of the troughs.
The pipes A and C are shewn circular in section, but they may be of any desired
section, and where the flues of a double-flued boiler are unusually close to-gether,
it may be considered desirable to use oval pipes.
"
Figure 5 illustrates in elevation a different method of raising and lowering the
"hood-pipe" C to that already described; g is a rod passing through a packing-
box c on the top of the hollow mounting D. This rod is cottered by means of a
cotter h (see enlarged detail section view of the top of the pipe C, Figure 6), into
a boss on the top of the "hood-pipe" C. The top of the rod g is connected to a
chain passing over a pulley l, and terminating in a hook n. The hood-pipe" C
is held up by hooking the hook n on to a ring or staple screwed or cast into, or
otherwise fixed, to the mounting D. The pulley 7 may be carried by a standard
or roof truss, or by any convenient means. The chain k may pass to the front of
the boiler if preferred and be actuated therefrom. According to this arrangement
guides on the pipes are not necessary, though they may be employed to keep them
central. The weight of the "hood-pipe "C may be partially counterbalanced by a
weight on the fall-end of the chain k.
Figures 7 and 8 illustrate an arrangement of my Invention applicable when the
blow-off outlet is above the boiler, as is sometimes the method adopted in the case
of plain cylindrical boilers; Figure 7 is a cross section, and Figure 8 a section on
line y', y, of Figure 7. A is the "hanging-pipe" fixed to the top of the hollow
mounting D by means of a faced joint. The pipe A extends above the top of the
mounting D, and by means of a branch is connected to the blow-off cock E, or
the blow-off pipes. C is the "sleeve-pipe" provided at its upper end with a
packing-box to slide on the pipe A (which is turned for the purpose), and provided
at its lower end with a cross-bar f, which is secured to lugs on each side thereof by
means of screws. A. screwed rod a, provided with a wheel and handle, and similar
to the rod a before described, passes through a packing-box at the top of the pipe A,
and extends down to the bottom of the boiler. This rod is screwed through a
thickened part of the bar f, and is shewn placed eccentrically with the pipes A
and C. A light rod o is passed through an eye on an extended part of the cross-
bar f, and fixed vertically within the boiler. The rod a may, if desired, be placed
centrally with the pipes A and C, in which case the lift on the pipe C is more
direct, but greater friction is thrown upon the guide rod o if placed in each case as
close as possible to the pipe, and any slight tendency which the eccentric rod a
has to prevent the turning of the pipe C is thus not taken advantage of. The
"hanging-pipe" A must not be fixed to extend below low-water level.
The pipe C

page_text: may, of course, be raised by means of a similar arrangement to that shewn at
Figure 5, the rod a in this case being, of course, fixed to the cross bar f, but not
continued below, and the guide arrangement may be dispensed with. This
modification cannot be depended upon for syphoning the water out to empty the
boiler. It is recommended that the arrangement be constructed so that the
packing-box and the bottom of the pipe A shall not descend below high-water
level, so as to be clear of scurf, which might otherwise prevent the easy sliding
of the pipe.
Figures 9 and 10 (Sheet 2) illustrate a modification of my Invention, suitable
for either double-flued or plain cylindrical boilers, or for any boiler in which
there is space to work it; Figure 9 is a part longitudinal section through the
boiler, shewing the improved blow-off apparatus in side elevation, and Figure 10
is a section on line Z, Z, of Figure 9. A is the "stand-pipe" fixed similarly to that
previous illustrated. B is a movable-pipe hinged to the pipe A by a trunnion joint
at C, consisting of a socket a on the pipe B, a collar b on the pipe A, and a gland c
divided in halves horizontally, and screwed up to the flange on the socket a, and
bearing against the collar b. The joint may be packed between the collar b and the
gland c, if desired, but I do not consider this at all necessary as long as the joint is
in good condition and does not leak badly, as a slight leakage will not prevent the
water syphoning out, and no leakage can take place, in ordinary working, below
low-water level. D is a quadrant cast upon the pipe B. A chain is held at one
end by the pin d in a groove in the face of the quadrant, the other end of the
chain being attached to the rod E, which passes up through a packing-box on
the top of the boiler, and is raised and lowered by a similar arrangement to that
illustrated by Figure 5 (Sheet 1). G is a lever cast on to the pipe B, and extending
beyond the fulcrum to carry the weight H, which partly counterbalances the weight
of the pipe B. The pipe B is lowered down for blowing out water from the bottom
of the boiler, and is raised up, as shown by dotted lines, Figure 9, for blowing out
scum. F is a trough-shaped vessel through the bottom of which the pipe B is
shewn to be lifted, when up, for better collecting the scum. A "hanging-pipe "
may pass down from a blow-off cock on the top of the boiler instead of using a
stand-pipe, and, of course, in either case the trunnion joint must not be below
low-water level.
Figure 11 illustrates in vertical section a modification of my Invention, partaking
in some respects of the nature of each of the modifications before described. This
nodification is given as an instance of several modifications, which will readily
suggest themselves to the mind of a person skilled in mechanics upon a perusal of
the foregoing description and Drawings. Figure 12 is a section on line Z, Z, of
Figure 11.
A is a stand-pipe," or, if turned the other way up, a " hanging-pipe."
B is a sliding-pipe, capable of vertical movement in the sleeve C formed out from
the top of the pipe A. When the pipe B is down in the position shewn, water from
the bottom of the boiler can rush up the pipe B when the blow-off cock is open,
through the opening a and down the stand-pipe A; but when the pipe B is raised,
with its lower end just above the opening a, the scum water only can rush into the
pipe A through the opening b or other openings formed as desired in the sleeve C.
The pipe B is prevented from turning by means of a key c, as shewn, fixed in the
sleeve C. An advantage of this modification is that a smaller opening will require
to be formed in the top of the boiler to receive the pipe B into the hollow mounting,
as the pipe B is smaller than when used as a "hood-pipe" or a "sleeve-pipe." The
communication also between the pipes B and A is cut off when the pipe B is lifted
with its opening at a clear of the corresponding opening in the pipe A. This
modification however is not recommended, as it will be liable to be choked up with
scurf in the sleeve, which must be bored to fit truly around the pipe B, and besides
this the water will not syphon out cold after the sleeve C has worn sufficiently for
the pipe B to be quite loose therein. The sleeve may be kept above high-water
level to be clear of scurf, but in this case the apparatus cannot be used for scumming.

page_text: The modification which I very much prefer, and recommend in all cases where it
can be used, is that illustrated by Figures 1 to 4, whether actuated as shewn, or
according to Figure 5.
Having now stated the nature of my said Invention, and particularly described
and ascertained the manner of performing the same, I declare that I claim as
my Invention, and desire to secure by the herein before in-part-recited Letters
Patent,-
1st. The employment of a "stand-pipe "or a "hanging-pipe" connected with the
blow-off outlet of a steam boiler, and terminating at or somewhat above low-water
level, and capable of being placed in communication with the water, either at the
upper stratum or at the bottom of the boiler as may be desired by means of a
suitable movable pipe, whether hinged or otherwise, substantially as and for the
purpose herein described and illustrated by the Drawings.
2nd. The blow-off apparatus for steam boilers, consisting essentially of the
"stand-pipe" A and the "hood-pipe" C, substantially as and for the purpose herein
described and illustrated by Figures 1 to 4 of the accompanying Drawings.
"
"
3rd. In combination with the blow-off apparatus referred to in claim 2 the
employment of the hollow mounting D, substantially as and for the purpose herein
described and illustrated by Figures 1 and 2 of the accompanying Drawings.
4th. The blow-off apparatus consisting essentially of the "hanging-pipe " A and
"sleeve-pipe" C, substantially as and for the purpose herein described and illustrated
by Figures 7 and 8 of the accompanying Drawings.
5th. In combination with the blow-off apparatus referred to in claim 4 the
employment of the hollow mounting D, substantially as and for the purpose herein
described and illustrated by Figure 7 of the accompanying Drawings.
"
6th. In combination with the blow-off apparatus referred to in claims 2 and 4
the employment of scum pipes or troughs, having a vertical part surrounding the
stand-pipe" or "hanging-pipe" and the "hood-pipe or "sleeve-pipe," substan-
tially as and for the purpose herein described and illustrated (as applied to a
'stand-pipe and "hood-pipe") by Figures 1 and 2 of the accompanying
Drawings.
7th. The blow-off apparatus consisting essentially of the "stand-pipe" A (or of a
"hanging-pipe") and movable pipe B, substantially as and for the purpose herein
described and illustrated (with a stand-pipe) by Figures 9 and 10 of the accompanying
Drawings.
Sth. In combination with the blow-off apparatus referred to in clain: 7 the
employment of a trough-shaped vessel or perforated pipe, with an opening through
which to receive the movable pipe, substantially as herein described and illustrated
by Figures 9 and 10 of the accompanying Drawings.
In witness whereof, I, tho said Stephen Watkins, have hereunto set my hand
and seal, this Ninth day of February, in the year of our Lord One thousand
eight hundred and eighty one.
STEPHEN WATKINS. (L.S.)
Witness,
HENRY CHILTON,
Clerk to Stephen Watkins, Assoc. M. Inst. C.E.,
Wolverhampton.