Improvements in or relating to Superheaters for Steam Boilers and Valves therefor.
Year: 1890

page_text: Date of Application, 17th Nov., 1890
Complete Specification Left, 14th Mar., 1891-Accepted, 2nd May. 1891
PROVISIONAL SPECIFICATION.
Improvements in or relating to Superheaters for Steam Boilers and
Valves therefor.
1, MAX GEHRE, of Rath near Dusseldorf, in the Empire of Germany, do hereby
declare the nature of this invention to be as follows:-
To avoid excessive pressure in the superheater connected with a steam boiler it
is proposed to arrange in addition to the ordinary back-pressure valve opening
into the superheater, another back-pressure or compensation valve which
according to its load, will, under a greater or less excess of pressure open
into the boiler.
Another arrangement consists in providing a valve between the superheater and
boiler which valve is normally closed by a piston-shaped projection which causes
no excess of pressure either in the superheater or the boiler; but which valve when
the pressure sustained by it is greater than the resistance of a spring buffer adapted
to receive the valve before it comes down on its seat, will be pressed against the
latter and thus closed.
The superheater may be arranged within the widened portion of the funnel or
chimney. The heating or flue pipes of the superheater are preferably arranged
vertically; and the products of combustion issuing from the boiler or furnace
partly escape through the said flue pipes while the remaining portion flows
round the walls of the superheater this heating the latter externally. Above
the superheating pipes the chamber contracts and assumes the ordinary shape of
a funnol.
In addition to the back pressure valve through which steam is periodically con-
veyed from the boiler into the superheater another check valve is arranged to open
into the boiler whenever the pressure within the superheater exceeds a certain limit,
which may result from the engine having remained inoperative for a somewhat
lengthy period or from other causes.
This additional valve thus acts as a safety valve as it prevents excessive steam
pressure in the superheater.
The back-pressure valve opening into the superheater may, by suitably adjusting
its load, be converted into a reducing valve and the excess of pressure under
which the safety valve will open into the boiler may be regulated at will.
Should moreover the steam be superheated to an extent capable of endangering
the piston and packing of the cylinder a water-jet arrangement of any suitable
construction may be set in operation to introduce a small amount of water
in the form of spray into the superheater and thereby to bring the steam nearer
to saturation.
In the instance here described the injecting arrangement consists of an injector
proper connected by a suction pipe with a water reservoir and fed with steam from
the dome or crown of the boiler. The saturation water is forced in through a pipe
which connects the injector with the superheater.
The steam dried in the superheater passes on, in the usual manner, through a
pipe to the cylinders; while the escape steam is discharged by the exhaust pipe
passing through the superheater and the funnel. Valves of this description may be
applied to steam superheaters of any construction whatsoever.
As the conical bodies of these valves are constantly rising from and falling on to
their seats both the cones and the seats are liable to rapid wear and the larger the
size of the valve the more powerful is the wearing effect of the strokes. The
consequence is that valves of this class do not close tightly beyond a short time
and necessitate frequent repair. Besides where conical valves of the ordinary

page_text: construction are employed the surface sustaining the steam pressure above the head
of the valve is larger than that pressed upon by the steam below the valve by the
whole area of the valve seat; whence result objectionable differences of pressure
between the superheater and the boiler which are very liable to interfere injuriously
with the action of the superheater.
To obviate these drawbacks a special arrangement has been devised in which the
two horizontal surfaces of the seat but very rarely come in contact with each other
in the ordinary operation or are entirely dispensed with and yet sufficiently tight
closing is obtained between the spaces containing superheated and saturated steam
to protect the former from saturation. The body of the valve here assumes a partly
cylindrical shape so that it exactly though removably fits the valve sent against
which it is pressed only when the steam pressure in the superheater becomes
excessive or when it is specially desired to close the valve this being effected by
means of a spindle and by overcoming the pressure of a spring.
Between the valve-box of well-known construction and the cover is inserted a
plate or diaphragm perforated for the reception of the valve spindle. This inter-
mediate plate serves the double purpose of an additional guide and means of
adjustment of the stroke of the valve and of a point of support or fulcrum for a
spring. A screw spindle serves for closing the valve and also for controlling the
stroke thereof. The arrangement is such that owing to the action of the spring
the closing surfaces of the valve and valve seat never meet under ordinary
circumstances the cylindrical portion of the valve forming a sufficient block between
the superheater and the saturated steam. There are preferably employed two
springs, one above and the other below the intermediate plate.
In an alternative device the horizontal closing surfaces are dispensed with
entirely a spring forming a protecting pad between the valve and the intermediate
plate.
Dated this 17th day of November 1890.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Superheaters for Steam Boilers and
Valves therefor.
1, Max GERE of Rath near Dusseldorf in the Empire of Germany, Engineer,
do hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:
In the back pressure valves as hitherto arranged between the steam boilers and
superheaters it has been observed that in consequence of the fluctuations of pressure
the valves constantly strike upon their seats as they are continually opening and
closing, the result being an exceedingly rapid wear of the valves which are usually
conical, and imperfect closing. The wear of the valve is thus very rapid and the
larger the size of the valve body the more powerful are its strokes and the more
considerable the wear, so that as a rule valves of this class are only capable for a
short time of closing in a perfectly steam-tight manner and demand frequent
repairs. Besides this, valves of the ordinary mushroom or conical construction
present to the steain above them a pressure surface larger than that which they
offer to the steam below by the amount of the whole area of their seat.
This gives
rise to material differences of pressure between the superheater and the boiler
which seriously interfere with the action of the superheater; it is the object of the
present construction of back pressure valve to avoid these drawbacks.
In the accompanying drawings
Fig. 1 is a vertical section of a valve adapted to carry out these improvements.
Fig. 2 is a similar view of a similar valve slightly modified from Fig. 1, and

page_text: Fig. 3 is another slight modification.
In these figures A represents the cock body, B the valve-seat and C the valve.
It will be seen that both the valve-seat B and the valve C are cylindrical and while
the valve is free to move in the seat it is made as close a fit as possible so as to
make a practically steam-tight joint. The valve as will be seen consists of the
cylindrical portion C and the webs or wings D turned to fit the cylindrical seating
and extending considerably below the body of the valve so that when the latter is
raised above the seating the wings will still remain in the seating and besides
keeping the valve in its proper position facilitate its return while the steam is
allowed free passage between the valve body and the seat and between the webs D.
In Fig. 3 the wings D are dispensed with and the spindle G (to be presently
described) continued below the valve and provided with an additional bearing P so
that the valve C remains in alignment with the seating B when removed from
contact with it as in its open position represented in Fig. 3.
This
The upper portion of the seating at is turned off true at a right or other augle
to the cylindrical portion and the valve C carries a flange or collar F turned to
correspond with this portion E of the seating, or the two parts are otherwise
arranged so as to make a tight joint, so that when the valve is forced quite home
an extra bearing between it and the seating is obtained and a perfectly tight joint
can be effected. The valve C carries an extension or spindle G which passes
through the bracket H secured between the body A and the cover I.
bracket H provides a second bearing to assist in steadying the valve and between
it and the spindle head J is a helical spring K which acts as a buffer when the
valve by a constant pressure of steam is forced hard down upon its scat. Upon the
spindle G also but below the bracket H is another helical spring or buffer L
preferably having a washer M above it which acts as a buffer in case the valve
is driven up very high from its seat. By these means all violent concussions are
avoided.
In the operation of this valve the steam from the boiler enters from beneath as
indicated by the arrow, raises the valve so that the cylindrical portion C is clear of
the seating B and escapes by the side passage, also as indicated by the arrow,
while back pressure in the reverse direction drives the valve back into the seating,
the cylindrical portion of the valve thus entirely closing the seating and preventing
the passage of steam while if the pressure of the steain be excessive the flange F
will be forced down upon the end E of the seating but this will be a gradual closing
as the spring K will then be called into play.
The screw spindle N which passes through a stuffing box O in the cover and is
provided with a hand wheel or equivalent outside to turn it by, can if desired be
screwed down upon the end of the spindle G so as to entirely close the valve or
regulate its stroke as required.
The construction and operation of the valve shown in Fig. 2 are substantially
the same excepting that the valve flange F and screwed spindle N are dispensed
with this valve also is shown with a straight through-way instead of having the
branches at right angles to each other. Excepting for the closing by the flanges F
and E the operation is precisely similar to that in the first case.
:
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a back pressure valve the combination with a cylindrical valve such as C
of a cylindrical seating such as B the closing being effected by the close though
movable contact between the two cylindrical surfaces substantially as described and
illustrated in the accompanying drawings.
2. In a back pressure valve the combination with a cylindrical valve such as C
working in a cylindrical seating of a flange or collar such as F adapted to engage
with the end of the said seating substantially as described and illustrated
Figure 1 of the accompanying drawings.
גון

page_text: 3. In a back pressure valve the combination with a cylindrical valve and a
cylindrical seating such as described of one or more springs or buffers such as K
or L for the purpose of obviating concussion substantially as described and
illustrated in the accompanying drawings.
4. The combination and arrangement of parts constituting the complete back
pressure valve substantially as described and illustrated in Figures 1, 2 or 3 of
the accompanying drawings.
.
1
1001
W. P. THOMPSON & BOULT,
Agents for the Applicant.