IMPROVEMENTS IN SAFETY VALVES FOR STEAM BOILERS
Year: 1857

page_text: LETTERS PATENT to Rudolph Bodmer, of 2, Thavies Inn, Holborn, in
the City of London, for the Invention of "IMPROVEMENTS IN SAFETY
VALVES FOR STEAM BOILERS."-A communication.
Scaled the 3rd July 1857, and dated the 23rd April 1857.
PROVISIONAL SPECIFICATION left by the said Rudolph Bodmer at tho
Office of the Commissioners of Patents, with his Petition, on the
23rd April 1857.
I, RUDOLPH BODMER, of 2, Thavies Inn, Holborn, in the City of London,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SAFETY VALVES FOR STEAM BOILERS" (a communication from a foreigner residing
abroad), to be as follows:-
It is a well-known fact that safety valves of the ordinary construction do
not, especially in the most urgent cases, admit of the escape of the steam in
proportion to the surplus evaporation of the boiler, and that, moreover, they
seldom or never completely close when the necessity for the escape of the
steam has ceased.
Now, these improvements have for their object to remedy these very serious
defects, and consist in a comparatively small weighted valve, which when the
pressure of the steam rises beyond its fixed standard is raised, and admits
through a pipe passing into the boiler, and reaching either above or below

page_text: the water level, steam or water upon a piston, which is in connection with
the steam escape or safety valve. Water is preferred to steam, on account of
its steadier action, arising from its want of elasticity. The water under the
pressure of the steam in the boiler will act upon the piston, and through
it upon the escape valve, and the lift of the piston can be so adjusted as to
afford a passage for the escape of the steam fully equal to the area of
the escape valve. To insure the closing of the escape valve, on the steam
pressure being reduced to its normal state, its area is made less than that
of the piston, and the steam from the boiler is admitted between the two, the
consequence of which arrangement is that as soon as the weighted valve
closes, owing to the reduced steam pressure in the boiler, the piston will,
because of the gradual escape of the water from underneath it, be gradually
and slowly depressed, and never fail to close the escape valve in proper time.
The escape valve may be placed either over or under the piston. In the
latter case,
the piston is acted upon by a spring, which closes the escape valve
in proportion as the water is expelled by the piston after the steam in the boiler
has been reduced to its normal pressure. A lever may be applied to raise
the weight by hand, so as to ascertain whether the valves are in good order.
And in cases where the piston is placed above the escape valve, it may be
connected by means of a lever with a weighted valve, controlling the admission
of the feed water, in such a manner that when, on the pressure of the steam
in the boiler rising beyond its proper limit, the piston descends, the valve is
raised, and admits the feed water into the boiler. By this means the feed
water is made to absorb a portion of the surplus heat, which would otherwise
be lost through the escape of the steam. If desired, a safety valve of the
ordinary construction may be made to act as the steam escape valve, in com-
bination with the small weighted valve and piston. In that case the piston
is continued downwards at a reduced diameter, and supports at its lower
extremity the short arm of the ordinary safety valve lever, the long arm being
pressed down by a weight or spring as usual. When the steam in the boiler
rises beyond its normal pressure the water which fills the space above the
piston forces the weighted valve opeu, and finds its way through a passage under
the piston, the surplus water at the same time escaping through a small
opening sideways. The piston will therefore, assisted by the pressure upon
the escape valve (in this case the ordinary safety valve), gradually rise until
the escape valve is open to its full extent, that is, until the circumference of
the valve multiplied by the lift is equal to the mean area of the valve. On
the steam in the boiler being reduced to its standard pressure the weighted
valve closes, and the piston will gradually and slowly descend, carrying the

page_text: escape valve lever with it, until the escape valve is also closed. In this case
also a lever can be applied to raise the weighted valve by hand, so as to
ascertain whether the valves act properly.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Rudolph Bodmer in the Great Seal Patent Office on the
23rd October 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RUDOLPHI
BODMER, of 2, Thavies Inn, Holborn, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of April, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Rudolph Bodmer, Her special licence that I, the said Rudolph Bodmer, my
executors, administrators, and assigns, or such others as I, the said Rudolph
Bodmer, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
SAFETY VALVES FOR STEAM BOILERS" (a communication from a foreigner residing
abroad), upon the condition (amongst others) that I, the said Rudolph
Bodmer, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Rudolph Bodmer, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the follow-
ing statement (that is to say):
It is a well known fact that safety valves of the ordinary construction, i. e.,
those in which the escaping steam raises and sustains the valve, do not,
especially in the most urgent cases, admit of the escape of the steam in pro-
portion to the surplus evaporation of the boiler, and that, moreover, they
seldom completely close when the necessity for the escape of the steam has

page_text: ceased owing to the valve presenting a larger surface to the pressure of the
steam when open than when it is closed.
Now, the object of these improvements is to remedy these very serious
lefects, for which purpose the safety apparatus is constructed in such a manner
that when the pressure of the steam rises beyond its fixed standard, steam or
water (the latter, however, in preference, on account of its steadier action)
is admitted, either under or over a piston, moveable in a regulating cylinder
or barrel by means of a pipe, which takes up the steam or water at such a
distance from the point where the steam escapes through the escape valve
as that no sensible diminution of pressure may take place. The steam or
water may either be admitted through a weighted valve, which rises as soon
as the steam exceeds its normal pressure, or it may be admitted directly, and
the piston upon which it acts may be in direct connection with the steam
escape valve; or the piston may be stationary, whilst the cylinder or barrel
forms the escape valve. In either case the escape valve is by the action of
the steam or water raised to a height from its seating, which, multiplied by
the effective circumference of the valve opening, shall produce an area equal
to that of the valve opening itself. To insure the closing of the escape valvo
on the steam pressure being reduced to its normal state, the area of the
piston is either made larger than that of the escape valve, and steam admitted
between the two, or water or steam, at the pressure in the boiler, is admitted
both over and under the piston, the area of one of the faces being reduced
below that of the other. The effect of this arrangement is that, owing to
the reduced pressure of the steam in the boiler, the piston will, because of
the gradual escape of the water (where water is used as a means for raising
the escape valve) through contracted passages, be gradually and slowly
depressed, and close the escape valve in proper time, though never suddenly
and violently. In cases where water is admitted over the piston without the
intervention of a weighted valve, it will on the steam pressure being reduced
be forced back into the boiler through the conducting pipe.
In order that this Invention may be more easily understood, and readily
carried into effect, I will now proceed to describe the same, reference being
had to the annexed Sheets of Drawings, and to the letters and figures marked
thereon. And I would also observe that the most essential parts recurring
in every modification of the improved safety apparatus herein-after described,
are throughout marked with the same letters of reference.
.In Sheet 1, Fig. 1 represents, in vertical section, one mode of constructing
the improved safety apparatus. The pipe A', whose upper end is fixed in
the socket 1, reaches down to a few inches below the water level in the

page_text: boiler. Another tube B, which by means of the pipe B', attached to it, also
dips to the same depth below the water level, terminates upwards in a spherical
or ball valve C, and in a cup C² above that. The valve C' so long as there
is no surplus pressure of the steam rests upon its seating a, whilst another
spherical valve C, to which the cup C² serves as a guide, has its seating at b.
A weighted box or casing 2, which rests upon the shoulder 3*, presses upon
both valves by means of the spindle 3, the lower conical end of which rests
in a corresponding indentation on the top of the valve spindle C³, whilst it
is guided above by a stay 4, which is fixed across the dome 5. To the lower
end of the pipe B' a weight is attached, which is immersed in the water.
and in consequence of the state of ebullition in which the water is kept
whilst steam is being produced, the pipe B' and tube B will be affected by
a slightly pendulous motion, which will prevent both the valves C' and C
from getting fast on their respective seatings. The pedestal 6 of the dome
5 is contracted in the centre to the size of the opening necessary for the
escape of the steam, and forms the seating c of the escape valve D, which
is screwed down upon the shoulder E', over the bush E³, by means of the
nut 7. The bush E is cast of one piece with the piston E, which must be
a good but easy fit in the cylinder F, and which is hollowed out to make
room for the valves C and C and their appendages. The cylinder F is
supported by four arms F', which unite it with a hoope F, the latter being
recessed partly into the dome pedestal 6 and partly into the flange 8. A
hoop 9 is similarly recessed into the steam pedestal 6 immediately above the
rim F, and supports by means of four arms 9" the conical roof 9b, which
fits tightly upon the cylinder F, and is intended, on the one hand, to limit
the lift of the piston E, and, on the other hand, as a protection to the piston
from injury by the dust which may drop down from the valve D when it is
being ground up. The steam has free access through the spaces between the
arms F and 9 under the valve D and over the piston E, and as the area of the
latter is about one and a half times as large as that of the former, the escape
valve D will remain closed so long as it is not otherwise acted upon. Now,
as soon as the steam rises beyond its normal pressure, which is determined
by the weight 2, the water which fills the pipe B will force the valve C open,
escape through the holes e in the cup C³ (see Fig. 2), and fill the space both
under and within the piston E. The piston E will therefore, owing to the
unbalanced. pressure upon the valve D, be gradually and slowly raised and
the escape valve D opened until the piston E is arrested by the roof 9b, where
it will form a steam-tight fit against the seating d, and close the cylinder F
in the manner of a valve. On the steam pressure being once more reduced

page_text: to its proper limit, the weight 2 will close the ball valve C, and the piston E
will descend as gradually and gently as it had risen, the water under and
within the piston in the meantime making its escape through the bush E²,
and round the ball guide C³ of the valve spindle C³ into the dome, where
the greater part of it will evaporate and make its way into the atmosphere
through the pipe 5*. A portion of the water will escape through the same
passages even whilst the piston E is being raised. It will be seen that the
pipe A¹ may contain either water or steam, according to circumstances, and
that the valve C' is quite at liberty to act in a similar manner to the valve C,
either by steam or by water pressure, in which case the valve C' carries the
valve C and its weight 2 with it, the weight suspended from the pipe B'
being so adjusted as to exert upon the valve C¹ the same pressure relatively
to its size that the weight 2 exerts upon the valve C, and both agreeing with
'the normal steam pressure. By means of the lever 10 the weight 2 can be
raised by hand from time to time, for the purpose of ascertaining whether the
valves are in good working order. The flange 8 is fastened to the boiler G,
and the steam dome 5 upon the flange 8 by means of bolts 8. With this
improved safety apparatus a valve of 34 inch diameter is amply sufficient
to admit of the escape of the steam to the full extent of the area of the valve
opening, whereas it would require a safety valve of more than 26 iuches
diameter to effect the same purpose if constructed in the ordinary manner,
and opening, as is generally the case, not more than one-eighth of an inch.
The apparatus shown in Sheet 2, Fig. 1, is almost indentical with that
described with reference to Sheet 1, the only difference being that the holes
marked e in Sheet 1 are omitted; that the cylinder F and piston E are shorter
and of a different shape, the former being besides supported in a different
manner; and that the roof marked 9b in Sheet 1, instead of forming a separate
piece is in this instance cast of one piece with the cylinder F; besides which
the spindle 3 instead of resting upon the top of the short stem C³ of the ball
valve C, as in Sheet 1, reaches down to the centre of the valve C, the stem of
which is moreover prolonged upwards, and furnished with a six-sided bead C³
to admit of the valve being ground up by turning it round with a screw
key.
In Sheet 2, Fig. 2 is a vertical section of a modification of the safety appa-
ratus, described with reference to Sheet 1; Fig. 3 shows another partly vertical
section of the same, with the valves in the position in which they are when
fully open. The pipe B', a prolongation of which reaches to a few inches
under the level of the water in the boiler, admits the water through the tube
and passage B under the ball valve C, which is weighted by the casing 1

page_text: placed on the spindle 2, the latter bein guided at its upper end by the cross
stay 8, whilst its lower conical end 2* is inserted in and resting upon the ball
valve C., As soon as the steam exceeds the pressure to which the ball valve C
is loaded, the water arriving by the pipe B' and passage B, lifts the ball valve
C from off its seating a, forces its way through the passage 4 and presses the
piston E downwards (see Fig. 3), and as the piston E, which must be a correct
but easy fit in the cylinder F. is by means of the spindle 5 connected with the
escape valve D (see Fig. 2), the latter will be forced open against the pressure
in the boiler, and allow the steam to escape freely between the escape valve
guides D', and through the openings 6 and 7 (sec Figs. 2, 3, & 4,) into the
dome 8, and from thence into the atmosphere by the pipe 8. The upper end of
the bush 9 which is recessed partly into the cylinder F and partly into the body
of the barrel 10, which latter serves as guide to the valve D by means of the
guides D', arrests the piston E as soon as the escape valve D has been
depressed from its seating to a sufficient extent, and when in that position
forms the roof of the steam passages 7. The spiral spring 11, which must be
of sufficient strength to raise the piston E to its original position, and to close
the escape valve D whilst the steam pressure rises in the boiler, surrounds the
spindle 5 and is confined longitudinally between the boss 9 of the bush 9 and
the nut 5, whilst the spindle 5 terminates in a ball end 5b, which is confined
within the valve D by a nut 12. The steam having been reduced to its normal
pressure the weighted valve C will close, and the water from above the piston
E will escape through the passage 4, and through grooves 6 cut for that pur-
pose in the ball valve C itself (see Figs. 5 & 6), and past its ball guide or
button C. A bridle 18 prevents the valvo D from falling into the boiler in
case of its being detached from the piston E. The lever 14 serves the pur-
pose of raising the weighted casing 1 by hand, in order to ascertain whether
the valves act freely.
In Sheet 3 an apparatus, similar to that described with reference to Sheet 2,
Figs. 2 & 3 of Drawings, is represented in combination with an arrangement
for admitting cold feed water into the boiler during the time the safety valve
is in action. As the piston E (see Fig. 1) is pressed downwards with con-
siderable force during the time that the safety or escape valve D is open, the
lever 15, whose bent arm 15 abuts against the under side of the piston E, is
thereby also depressed, so that the weight 16 with which the valve 17 is con-
nected by means of a rod 17" and a bush 17b, is raised by the lever arm 15b,
and allows the water from the feed pump to be injected into the boiler through
the pipes 18 & 19 at a depth of a few inches below the water level. By this
arrangement a portion of the steam is condensed, so much less steam is blown

page_text: off, and the surplus heat of the water in the boiler is absorbed by the cold
feed water thus admitted. The weight 16 must, as a matter of course, be
regulated by the pressure of the steam and by the area of the valve 17.
Sheet 4 represents the improved system of effecting the lift of the escape
valve as applied in combination with a valve similar to an ordinary safety
valve, an arrangement which is peculiarly adapted for locomotive engines.
Fig. 1 is a front view, showing a portion of the boiler and the safety or
steam escape valve, in section; Fig. 2 a side view, partly in section; and
Fig. 3, a view from above. The safety or escape valve D is guided by the four
wings or diaphragms D¹ within the barrel 1. It is weighted by means of the
lever 2 acting upon the pin 3, and as the points of application of the pin 3 lic
on the one hand in the centre line b, c, of the lever 2, and on the other in a
horizontal plane nearly corresponding with the lowest part of the wings D' of
the escape valve, the latter must necessarily at all times occupy its proper
position on its seating, and the wings D'aro exempt from any side pressure.
The lever 2 is held down by the usual spring balance 4, and is connected by
means of the bridle 5 and the rod 6 with the hollow piston E, the rod 6 of
which passes through a stuffing box 9, whilst the bridle 5 is guided by two
forks F, which are cast to the cylinder F, in which the piston E is a tight fit,
and which is by means of the bracket F attached to the boiler. Tho space
over the piston E is in constant communication with and filled with water
from the boiler through the tubo 7. A lid 8 closes the cylinder F at the top,
and bottom plate 9 is fitted with a ball valve C, which is pressed downwards
by the rod 10 through the instrumentality of the spiral spring 11. This
spring is contained within the casing 12, which is fixed to the bottom plate 9,
the latter being perforated immediately over the ball valve C, so as to serve as
its guide through the button C', which is cast of one piece with it. The pipe
B places the ball valve C in communication with the water in the boiler,
being jointed above to the branch pipe B, which projects from the bottom
plate 9 and below to the branch 13, which projects from the flange B³ by
means of the nuts 13 & 18ª, for the purpose of facilitating its removal. As
soon as the ball valve C is raised, owing to the excess of the boiler pressure
over that to which the spring 11 is regulated, the water from the boiler will
penetrate through the pipes B2, B3, B and through the passage 14 under the
piston E, and neutralize the pressure upon it; and as the lever 2 (see Fig. 1) S
is, by means of the spring balance 4, the bridle 5, and the piston rod 6, in
connection with the piston E, the escape valve D is thenceforth at liberty to
rise, until it is checked by the top of the piston E coming in contact with the
lid 8, by which time the lift of the escape valve D will be completo; the

page_text: water over the piston E having been forced back into the boiler, and the space
under it having at the same time been filled by the water forcing its way
from the boiler through the pipes B², B, B, and passage 14. When, in con-
sequence of the pressure in the boiler having been reduced to its proper
standard by blowing off, the ball valve C closes the pressure upon the under
sido of the piston E is removed; the piston is therefore, owing to the pressure
upon the water in the boiler, once more depressed, and the water from under
it expelled through the passage 14 through the grooves in the ball valve C
(see Fig. 4) round the button C', and through the waste pipe 15 in the direc-
tion of the arrow, whereupon the escape valve D will also close. From the
extremity of the long arm of the lever 2 a pin 16 projects, from which is
suspended the rod 17 by means of the bush 17, into which the rod 17 is
screwed, an adjusting nut 17 admitting of the length of the rod. being regu-
lated at pleasure. This rod 17 serves the purpose of compressing the spiral
spring 11, and its lower end passes through the bush 18, which is screwed on
to the top of the casing 12 by the screw thread 18". When in consequence
of the increased pressure of the steam in the boiler the escape valve.D begins
to rise, the rod 17 recedes from the spring 11, whereby the ball valve C is
relieved, in consequence of which it opens, thus producing the effect already
described. On the steam pressure in the boiler subsiding altogether the
pressure upon the piston E also vanishes, and the spring balance 4 is reduced
to a state of rest; but as soon as the pressure again rises, the tension upon
the spring balance will increase in the same proportion.
In Sheet 5, Fig. 1 is a front view, partly in section, of another modification
of the improved safety apparatus, (similar to that described with reference to
Sheet 4,) acting in connection with the cold feed water admission valve; Fig. 2
being a longitudinal elevation; and Fig. 3 a ground plan of the same, with
the lever and spring balance removed. The escape valve, which is not shown
in the Drawing, is supposed to be 4 inches in diameter. The arms of the
lever 1, through the intervention of which the weight or spring balance acts
upon the escape valve, are in the proportion of 1 to 9. The regulating
piston E is here represented as being in connection with the spring balance 2,
of which only the top and bottom, with a very small portion of the barrel '2",
are shown in the Drawing. The upper end of the spring balance 2 is hinged
to the lever 1 in the usual manner, whilst the lower end thereof is connectedl
with the piston E by means of the rod 3 and the regulating screw 4; the
latter being grasped by a slot in the hook 3, in which the upper end of the
rod 3 terminates (see Fig. 3.) Whilst the apparatus is not in action,
the pistou E rests upon the seating a, forming a steam-tight fit upon the

page_text: bottom plate 5, and allowing neither steam nor water to penetrato into
the passage 6, although the piston E does not form a tight fit in the cylinder
or barrel F. And it will be at once understood, that any small quantity of
water which may find its way through between the piston E and the cylinder
F, whilst the apparatus is in action, can in nowiso affect its efficiency.
Whether the lever 1 be acted upon by weights, or by a spring balance, as
indicated in the Drawing, the general arrangement would only in so far have
to be modified in the former case, that, instead of the regulating screw 4, a
prolongation of the piston rod 3 would have to be connected with the weight,
which latter would consequently bo raised by the piston E, and that the ball
valve C would have to act in concert with tho weight, instead of acting with
the spring balance, as shown in the Drawing. When, owing to the surplus
pressure of the steam in the boiler, the escape valve begins to rise and to lift
the lever 1, and through it the spring balance 2 and the rod 7, through the
medium of which latter and the spindle 9, the spiral spring 8 (which is con-
fined between two collars 8 & 8b at top and bottom) presses upon the ball
valve C. The tension of the spring 8 becomes reduced to the extent
determined by the space left between the lid 11 of the spring casing 10 and
the collar 8. The ball valve C thus relieved, will therefore rise at the same
instant, and admit water from the boiler through the passage 6 under the
piston E; the water above the piston E in the barrel F being at the same
time forced back into the boiler through the tube 12, (see Figs. 1 & 3.)
The piston rod 3 will consequently raise the lever 1, and allow the escape
valve to rise to the required height, and keep it open so long as is necessary
to reduce the steam pressure to its normal state. As the ball valve C is
weighted by means of the spiral spring 8, in the position in which it is shown
in the Drawing, exactly to such an extent, that on the steam pressure rising
beyond the fixed standard, it will be forced open by the water arriving from
the boiler through the pipe B', B, thereby admitting the water under the
piston E; the escape valve will be set free by the rising of the piston E in
the manner already described. And it will be seen, that the escape valve and
ball valve thus react upon each other, and tend to produce the same result,
whereby increased safety is insured. The ball valve C has sufficient play in tho
box, and the button C¹ in the aperture within which it is confined, to allow the
water which is forced back by the descent of the piston E on the steam
pressure in the boiler being reduced, to escape and to flow off through the
tube 10%, and it only remains to be observed, that the aperture which serves
.as a guide to the button Cand the seating of the ball valve C, must be
equally large. The whole apparatus may be attached to the boiler by means

page_text: of an angle piece 17. The opening of the cold feed water valve is effected in
the following manner:-As soon as the piston E begins to rise as above
described, the rod 3 rises with it, and presses, by means of the tappets 3b, one
of which projects from the hook 3ª on either side, against the fork lever 13,
which, by means of the tail piece 18, is hinged upon the pin 18, between
two ears 14, projecting from the stuffing box 14. The spur 13%, which
projects outward from the tail end 13 of the lever 18, is thereby depressed,
pushes the rod 15 downwards, and thereby forces open the feed water admission
valve 15 against the pressure of the feed pump, so that the water ascending
through the tube 5b is forced into the boiler through the pipe 16.
In Sheet 6 of Drawings, Fig. 1 represents in sectinal elevation another
modification of the improved system of safety valves for steam boilers; Fig. 2
is a ground plan of the same, with the steam escape valve removed; Fig. 3
being a section through the valve plate, valve seating, piston, and water or
steam admission pipe; and Fig. 4 showing in ground plan one half of
the valve plate, with the piston and its stem cut off level with the valve
seating.
In this apparatus, instead of employing a cylinder and a moveable piston
in connection with the escape valve, as described with reference to the pre-
ceding Sheets of Drawings, the arrangement is reversed, a fixed piston being
made use of as a guide for a cylinder, either in direct connection, or of one
picce with the escape valve. The piston E is cast of one piece, with the
circular foot plate E' being connected therewith by means of the four wings
or diaphragms E2 & E³, the latter also uniting the plate E' with the tube
B, through which steam or water is admitted between the piston E and
the cylinder or cap D, F, which latter with its lower rim a upon the valve
seating b, so long as the steam does not rise beyond its standard pressure, and
thus forms the safety or steam escape valve. The cylinder or cap D, F, is
turned internally, so as to be a good, but easy fit upon the piston E, and it
is further guided by the four wings or diaphragms E², which extend to the
circumference of the piston E, and are turned at the same time, and to
the same diameter as it. The pipe B' is screwed or otherwise fastened into
the socket B² of the tube B, and when steam is to be used for raising tho
escape valve, it must be bent sideways, so as to take up the steam at some
distance from the point of its escape, in order that it may undergo but little,
if any, diminution of pressure, owing to such escape. Where water is made
absolutely necessary to
use of as a means of lifting the escape valve, it is not
take this precaution. The top of the cylinder or cap D, F, is formed and
turned out in the shape of a funnel, in order to bring the point of application

page_text: of the spindle 1 as closely as possible to the level of the valve seating, and it
is scarcely necessary to say, that between the funnel-shaped indentation of the
cap D, F, and the corresponding recess in the piston E and tube B, sufficient
space must be left for the free passage of the steam or water, with allowance
besides for the grind up of the valve and scating. The pillar or stud 2
rests upon the foot 2", (see Fig. 2) which is of the form of a segment of a
circle, and the bolts 2b, (see also Fig. 2,) which hold it down upon the plate
E¹, at the same time unite together the plate E' and H, the latter being
screwed upon the boiler G in the usual manner.
The slot 2° in the upper
and enlarged end of the stud 2, serves as a guide to the short arm of the
lever 3, and the foot 4 of the blow-off pipe 4 is hold down upon the sides of
the dome 5 by means of the nut 2d on the stud 2°, the conical end of which
constitutes the fulcrum of the lever 3. The foot 6" of the pillar or stud 6 is
similarly to the stud 2 attached to the plates E¹ & H by the bolts 6ª, the
slot 6 in its upper and enlarged end acting here as a guide. to the long arm
of the lever 3, and the nut 6° performing the office of holding the foot of the
blow-off pipe 4 down upon the dome 5.
Now, upon the pressure of the steam in the boiler rising beyond that to
which the escape valve D, F, is adjusted, (and which adjustment may be
effected either by a weight, as shown in the Drawing, or by a spring balance)
the water or steam admitted through the pipe B¹ and tube B, raises the
cylinder or cap D, F, from its seating at 6 to the required height, as shown in
dotted lines a, a, in Fig. 1, and allows the steam to escape freely; the circum-
ference of the escape valve, multiplied by the height of the lift, representing
an arca fully equal to that of the passages c (see Figs. 3 & 4) in the
plate E. This apparatus also recommends itself for its comparative cheap-
ness and simplicity; the piston E, plate E¹, and tabe B, consisting of onc
picce, which is capable of being completely finished on the lathe.
It will be perceived that, when the cylinder or cap D, F, is lifted by means of
steam, it need not form such a very accurate fit on the piston E, inasmuch as,
after the escape valve has been raised, an escape of steam along the piston
cannot do much harm. In fact even a slight escape of water, where water is
used for raising, the escape valve, could not be very prejudicial, since such
loss would only take place during the comparatively short period of the
blowing off.
As in this modification of this improved safety apparatus, as well as in the
apparatus described, with reference to the precceding Sheets of Drawings, it
is not the blow-off steam which has to lift and keep the
escape valve open, but
the steam or water which is taken up at the full boiler pressure at a remote

page_text: and lower part of the boiler; it is evident that this steam or water will act
with a more uniform pressure upon the escape valve, and is therefore more
likely to raise it and to keep it at the proper height for the free escape of the
steam than is the case with ordinary safety valves, to which this system has
not been applied.
The connection with the feed water admission valve 7 is effected by means
of a prolongation 3ª beyond the extreme end of the short arm of the lever 3,
which is furnished with a set screw 3b, and depresses the valve rod 7" whilst
the escape valve is open, and steam is therefore being blown off. In the
absence of steam pressure in the boiler, a spiral spring may be applied to close
the valve. It is evident (and this observation applies to all similar cases) that
the size of the feed water valve must be regulated according to the quantity of
steam which is capable of issuing through the fully opened escape valve under
a given pressure; so that in no case more steam can blow off than will be
immediately and amply replaced by the injected feed water, which will in its
turn at once re-establish the normal steam pressure and arrest the blowing off.
Sheet 7 represents the improved system of raising the escape valve in com-
bination with a valve similar to an ordinary safety valve. Fig. 1 showing, in
vertical section, a piston and ball valve, similar to those previously described;
and Fig. 2, also in section, the escape valve; Fig. 3, being a ground plan of
the former, and Fig. 4 a ground plan of the latter; Fig. 5 a vertical section
of the apparatus through the line A, B (Fig. 3); and Figs. 6 & 7 respectively,.
sections through the lines C, D, and E, F (Fig. 3).
A pipe attached to the short tube B conducts the water from the boiler into
the passages 1 (see Fig. 6), and into the space between the top of the piston E
and that of the cylinder F (see also Figs. 1 & 5). A prolongation E¹ of the
piston E, but reduced in diameter, extends downwards, and forms an exact but
easy fit in that part of the barrel 2 which immediately adjoins the cylinder F ;
this piston or plunger E' is still further reduced at its lower end E', through
which a slot or groove a is cut (see Figs. 1 & 5), which admits and carries the
extreme end of the short arm of the escape valve lever 3, upon which the
piston bears, through the interposition of steel centre pins 3* which are partly
recessed into E, and partly into the lever 3; the latter bears at 6 (sec
Fig. 2) upon the spindle 4, which in its turn bears upon the escape valve D,
which is guided by the wings D', whilst the long arm of the lever 3 is, by
means of the rod 5, connected with a spring balance or weight, as the case
inay be, in the usual manner. Now, when the pressure of the steam rises
beyond the required limit, it will, in the first instance, slightly raise the escape
valve D. The steam pressure however still going on increasing, the water in

page_text: the passages 1 and cylinder F will cause the ball valve C to be raised (see
Figs. 1 & 5), whereupon the water will force its way down the passage 6
(see Fig. 7), and under the piston E, whilst at the same time a small portion
thereof will begin to escape through the small opening in the tube 7. The
pressure of the water above the piston E will thus be counteracted to the
extent of the difference between the area of the piston E and that of its pro-
longation E¹; and the piston E will therefore, assisted by the pressure upon the
escape valve D, be gradually and slowly raised, until the upper face of it shall
have assumed the position indicated by the line y, by which time the escape valvo
D will be completely open, as indicated in dotted lines in Fig. 2. And whilst
the short arm of the lever 3, guided in the slot f, follows the motion of the
piston E, the spring balance or weight at the opposite end will hold the long
arm down upon its rest d in the fork 8 (see Fig. 8). As soon however as the
pressure of the steam becomes reduced to its proper standard the ball valve C
will close, and the water under the piston E will gradually and slowly escape
through the hole c, and allow the piston to descend until after it has resumed
its position on the seating e, as shown in Figs. 1 & 5, the escape valve D will
also have become closed, owing to the connecting existing between the piston
and the lever, which has been above described, and the long arm of the lever 3
will again be raised from its rest d to the position in which it is shown in the
Drawing. The water which escapes through the pipe 7 may either be carried
off altogether, or be brought within reach of the feed pump. A dish 2ª,
cast on the lower part of the barrel 2, collects any water that may find its
way to the outside, especially through the slots f, and allows it to drop into
the bottom of the barrel 2 through the holes 2 (see Fig. 5), and as soon as
the water accumulates so as to reach the pipo 9, the latter carries it off to the
feed pump or elsewhere. In order to enable the attendant at all times to
ascertain whether the valves are in good working order, a rod 10 (see Fig. 8),
acted on by a spring 11, is connected by means of the elbow lever 12 and
rod 18 with the crank 14, which is fixed at one end of a short shaft 15,
passing through a bush 16 which is screwed into the cylinder F. The
enlarged end of the shaft 15, which projects into the cylinder F, is intended
at the same time to close the bush 16, and to support the pin or spindle 17,
which has to act upon the valve C. For this purpose the enlarged end of the
shaft 15 nearest to the bush 16 is turned conically, and fits tightly into a corre-
sponding recess in the bush, like a valve on its seating, whilst the ledgo 15"
supports the shoulder 17 of the spindle 17, which extends downwards
in a short length 17" through a conical hole g; as soon therefore as the
attendant either pulls or pushes the rod 10, the shoulder 17 will be raised on

page_text: its edge and lift up the ball valve C, which is acted upon by a spiral spring 18,
whose tension is regulated in accordance with the steam pressure required to
be kept up in the boiler. The boiler is supposed to be furnished with two
safety valves (one on each side of the regulating apparatus) which are acted
upon simultaneously in the manner above described. The method of fixing
the various apparatus on the boiler is similar to that in ordinary use, and
requires therefore no further description.
Instead of the arrangements above described, the apparatus represented in
Figs. 1 & 2, Sheet 8, may be employed. In this case the construction of the
passages, cylinder, and piston is the same as before or nearly so; but instead
of the spiral spring 18 pressing upon the ball valve C, the weighted casing 1
and spindle 2 are substituted, and these are similar in construction to those
described with reference to Sheets 1 & 2, and act in a similar manner, with .
the exception that the dome 3 is closed at the top, and that the pipe 4 carries
off the water, which escapes past the ball valve and its guide.
Figs. 3 & 4 represent a modification of the apparatus for ascertaining
whether the valves are in good order, and this in combination with the safety
valve lever 5, by means of the stud 6 which is screwed into the lever at a
short distance from its outer end. The stud 6 passes through a slot a in the
lever 7, one arm 8 of which carries a swivel joint 8, in which the rod 9 is
secured, the latter being at its other end connected with the arm 10 of an
elbow lever (see Fig. 1), whose other arm 11 reaches under the weighting appa-
ratus 1. Now, whenever the safety valve acts in the usual manner, the stud G
moves up the slot a, which forms an inclined plane, draws the rod 9 in the
direction of its arrow, and raises, by means of the elbow lever 10, 11, the
weight casing 1, so as to allow the ball valve C to rise, whereby the escape
valves will be set at liberty, and rise also, in the manner already described.
The same effect may be produced by raising the long arm of the lever 5.
Having now described the nature of these improvements, as well as various
modes of applying the same so as to suit different circumstances, I wish
it to be understood that I do not confine myself to the particular details of
the arrangements herein-before described; but what I claim as the Inven-
tion, intended to be secured to me by the above in part recited Letters
Patent, is,
Firstly, the pipe or tube marked B, B', in Sheets 1, 2, 3, 5, & 6 of Draw-
ings; B, B', B, in Sheet 4 of Drawings; and B, in Sheet 7 of Drawings, by
which pipe or tube the steam or water which is intended to lift the safety or
escape valve is taken up at such a distance from the point at which the

page_text: steam escapes, as that its pressure shall not be sensibly diminished by such
escape.
Secondly, the weighted valve marked C, in Sheets 1, 2, 3, 4, 5, 7, & 8 of
Drawings, the object of which valve is to be raised by the steam or water
(admitted as described) so soon as the pressure in the boiler exceeds the
required standard, and to admit such steam or water either over or under the
regulating piston, marked E throughout the Drawings, which piston moving
in a cylinder marked F, is either directly or indirectly connected with the steam
escape or safety valve marked D, in Sheets 1, 2, 3, 4, 5, 7, & 8, and D, F, in
Sheet 6 of Drawings, and on being raised or depressed, as the case may be,
opens the steam escape or safety valve to the required extent..
Thirdly, with regard to Sheet 1, and to Fig. 1, in Sheet 2 of Drawings, the.
.peculiar combination of the weighted valve marked C, with the lift valve
marked C', which admits of the action of either the one or the other. Also
the tube or pipe marked A', which prevents the steam from gaining access
to the valves C & C¹, when water is to be used as a means of raising the
escape valve.
Fourthly, with regard to Sheet 2 of Drawings, Figs. 2 & 3, the peculiar
combination of the valve C, piston E, and escape valve D, by means of which
the latter is made to open downwards, when, owing to the surplus pressure in
the boiler, tho water or steam raises the valve C.
Fifthly, with regard to Sheets 3, 5, & 6 of Drawings, the connecting the
safety apparatus with the feed water admission valve in such a manner that,
whilst the steam escape valve is open, cold feed water is being admitted into
the boiler, for the purpose of absorbing the surplus temperature of the water
in the boiler, and thus reducing the quantity of steam to be blown off...
Sixthly, with regard to Sheets 4 & 5 of Drawings, the peculiar combination
of the piston marked E, with the spring balanco marked 4, in Sheet 4, and
2, 2ª, 2, in Sheet 5, the upper end of the cylinder or barrel marked F, being
in constant communication with the water in the boiler. Also the establishing
a connection between the weighted valve marked C, and the spring balance or
weight which act upon the escape valve, by means of a rod marked 17 in
Sheet 4 and 7 in Sheet 5, so as to cause the weighted valve (C) and the
escape valve to act mutually upon each other, thereby insuring greater
certainty of action, and consequently greater safety.
Seventhly, with regard to Sheet 6 of Drawings, the making the piston
marked E stationary or fixed, and the cylinder or barrel marked D, F,
moveable on the piston, the cylinder or barrel forming at the same timo or
9

page_text: being in immediate connection with the steam escape valve. Also the
peculiar combination of the piston marked E, with the tube marked B, and
foot plate marked E¹, the latter forming at the same time the valve seating,
and containing the spaces marked c for the escape of the steam from the
boiler.
Eighthly, with regard to Sheets 7 & 8 of Drawings, the peculiar com-
bination of the piston marked E, with a double set of lever, safety, or escape
valves. Also the peculiar combination of the piston E, with the valve lever
marked 3 in Sheet 7, and 5 in Sheet 8, and the effecting the gradual opening'
of the escape valve, by causing the water above the piston E to raise the
weighted valve marked C, and to penetrate also under the piston. Also the
combination of parts marked 10, 11, 12, 18, 14, 15, 16, 17, & 17 in Sheet 7,
and 1, 8, 9, 10, & 11 in Sheet 8, the object of which is to ascertain whether
the valves are in proper working condition, as well as to connect the steam
escape valve with the weighted valve.
Ninthly, with regard to Sheets 1, 2, 3, 4, 5, 6, 7, & 8 of Drawings, the
regulating the closing of the steam escape valve, by compelling the water
under or over the piston to force its way through contracted openings or
passages, after the pressure in the boiler has been reduced to its normal
state.
In witness whereof, I, the said Rudolph Bodmer, have hereunto set my
hand and seal, this Twenty-third day of October, in the year of our
Lord One thousand eight hundred and fifty-seven.
זת זמת
-גותה
RUDOLPH BODMER.
(v.S.)