IMPROVEMENTS IN APPA- RATUS APPLICABLE TO STEAM BOILERS.
Year: 1858

page_text: LETTERS PATENT to Thomas Greenhalgh, of Bury, in the County of
Lancaster, Manufacturer, for the Invention of "IMPROVEMENTS IN APPA-
RATUS APPLICABLE TO STEAM BOILERS.".
PROVISIONAL SPECIFICATION left by the said Thomas Greenhalgh at
the Office of the Commissioners of Patents, with his Petition, on the
3rd August 1858.
I, THOMAS GREENHALGH, of Bury, in the County of Lancaster, Manufacturer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
APPARATUS APPLICABLE TO STEAM BOILERS," to be as follows:-
The object of the first part of my Invention is to admit feed water into the
boiler. The apparatus consists of a pipe of about twelve feet in length, or more
or less, one end of which passes into the boiler a little below the required level
of the water; the other end of this pipe is in communication with a valve
through which the feed water has to pass. This pipe may be supported
between stay rods or otherwise. As long as the water remains at the proper
level in the boiler the pipe is kept cool, and the valve remains closed, but as
soon as the water descends sufficiently to uncover the end of the pipe, the steam
passes through the pipe, thereby heating and elongating it; this expansion of
the pipe opens the valve, and the feed water then passes through the valve, and
through a pipe into the boiler.

page_text: The object of the second part of my Invention is to give notice when the
water in the boiler descends below a certain level, and the apparatus consists
of a pipe opening into the boiler and placed at the level below which it is
considered unsafe to work; this pipe is twelve feet or more or less in length; to
the outer end is fixed a valve box, which is guided between two stay rods
furnished at the end with an adjustable crosshead. When the water in the
boiler is at or near its proper level, the water in the pipe remains cool, because
the valve at the end of the pipe is kept closed, but as soon as the water in the
boiler descends below the level of the end of the pipe, the water from the pipe
enters the boiler, the steam then entering the pipe heats it, and causes it to
clongate by expansion; the spindle of the valve at the end of the pipe is thus
brought against the crosshead of the stay rods, and opens the valve, the steam
then makes its escape, and it may be made to sound a whistle or other alarum
to call the attention of the workmen. When the level of the water in the
boiler again rises, the end of the pipe must be closed by suitable means, and
the apparatus remains in action until the boiler is again short of water.
The object of the third part of my Invention is to allow steam to escape
when the pressure thereof is greater than desirable. The apparatus for
effecting this consists of a pipe opening into the boiler and in communication
with a mercury gauge of the usual construction, and with a pipe supported
between stay rods; the bottom of the mercury gauge opens into a vessel into
which another pipe from the boiler enters; as long as the steam is under the
pressure determined upon, the mercury remains in the gauge, and the steam
cannot escape through the pipe supported between the stay rods, consequently
the said pipe remains cool; but when the steam exceeds the desired pressure
the mercury is blown out of the mercury gauge into a receiving tube, and the
steam escapes through the pipe supported in the stay rods, thereby heating
and elongating it. The elongation of this pipe causes the stay rods to open a
safety valve, thereby allowing the steam to escape until the pressure is
sufficiently reduced, or until the communication is shut off between the boiler
and the mercury gauge. The escape of steam may also. be. made to sound a
whistle or other alarum.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Greenhalgh in the Great Seal Patent Office on the
21st January 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
GREENHALGH, of Bury, in the County of Lancaster, Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of August in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-second year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Thomas Greenhalgh, Her special licence that I, the said Thomas
Greenhalgh, my executors, administrators, and assigns, or such others as 1,
the said Thomas Greenhalgh, 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 "IMPROVE-
MENTS IN APPARATUS APPLICABLE TO STEAM BOILERS," upon the condition
(amongst others) that I, the said Thomas Greenhalgh, my executors or
adininistrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and
nature of the said Invention, and in what manner the same
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.
ascertain the
was to be
NOW KNOW YE, that I, the said Thomas Greenhalgh, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement (that is to say) :-
The nature of my said Invention consists, first, in an improved apparatus
applicable to steam boilers, by which the supply of feed water is regulated.
Secondly, in an improved apparatus by means of which notice is given
when the water of a steam boiler descends below a certain level.
And, lastly, in an improved apparatus for allowing steam to escape when
the pressure in the boiler exceeds the required limits, part of which forms a
mercury safety valve.
And in order that my Invention may be fully understood and readily carried
into operation, I will proceed to describe the means pursued by me, reference

page_text: being had to the accompanying Sheet of Drawings, and to the figures and
letters marked thereon.
Figure 1 is an elevation, partly in section of my improved apparatus,
applicable to steam boilers, for regulating the supply of the feed water.
Figure 2 is a transverse section of part of the same. a, is a pipe connected
to the force pump in the ordinary manner; b is a valve seating fixed in the
elbow pipe a¹; c is the valve fitting the seating b, this valve is closed by the
expansion of the pipe or tube d, which I prefer to make twelve feet long, but
it may be longer or shorter, if required. To the outer end of the tube d is
secured the coupling piece e, into which the screw fits loose, this screw is
screwed into the crosshead g, and to it is fixed the hand wheel h. To the
other end of the tube d is fixed the connecting rod d¹, which passes through
the stuffing box in the elbow of the pipe į, through which the water is
conveyed to the boiler. The stay rods h, k, pass through the flanges of the
stuffing box i¹, and the crosshead g, and they are connected to each by double
nuts; these stay rods are supported by the fixing . The pipe d is connected
to the tube d, and is for the purpose of allowing the condensed steam to run
off; the pipe 3 is connected to the other end of the tube d, and is in com-
munication with the fixing m which is screwed to the top of the boiler
marked m', this fixing serves as fulcrum for the lever n, to one end of which
is suspended the float n¹ and to the other the weight n². The fixing m also
serves to support the two valves o and p, the former of which is to open and
close the communication between the pipe d³ and the boiler, and the latter
opens and closes the communication with the pipe q, the object of which will
be explained hereafter. The shanks of the valves o and p have springs coiled
around them acting on shoulders; the object of these springs is to close the
valves when the projections n³ and n are not influencing the positions of the
said valves.
The mode of operation is as follows:-the Drawing represents the parts in
the positions they occupy when the water in the boiler is at its proper level;
the float n then keeps the lever .n about horizontal, and the projection n
acting on the shoulder of the valve o holds this valve off its seat, consequently,
the steam passing through the pipe d³ into the tube d heats and expands the
tube, and as the tube is held fast by the crosshead g, it is evident that the
expansion of the tube causes the connecting rod d¹ to hold the valve c against
the seating b, consequently the supply of feed water is shut off until the level
of the water in the boiler, in descending, allows the float n¹ to drop until the
lever n comes into the position shewn by dotted lines, or sufficiently low to
remove the projection from the shoulder of the valve o, when the spring

page_text: acting on this valve presses it against its seating and closes the communication
between the boiler and the pipe d. By thus shutting off the steam from the
pipe d³ and tube d, the heat of the tube will be reduced until it contracts
sufficiently to draw the end of the connecting rod d' out of contact with the
valve c, when the pressure of the feed water on the said valve will force it
off its seating, and the water will then flow through the pipe to the boiler,
as indicated by the arrows in Figure 1. The object of the hand wheel h and
screw is to be able to adjust the position of the tube d and rod d', according
to that of the valve c, and also to be able to remove the end of the rod d¹
from the valve c, when it is requisite to supply a greater quantity than usual of
feed water to the boiler.
My improvements in apparatus for giving notice when the water in the
boiler descends below a certain level, will be readily understood in reference
to Figures 1, 3, 4, and 5. Figure 3 is an end view of a boiler on a reduced
scale; Figure 4 is a sectional elevation, and Figure 5, a plan, of the escape
valve and parts connected therewith. r is a vertical tube of twelve feet or
more or less in less in length, similar to the horizontal tube d in Figure 1; to
the upper end of the tuber is fixed the crosshead r', supported by the stay
rods s, s, the lower ends of which are secured to the lid s¹ of the valve box s³,
this valve box is bolted to the short pipe fixed to the top of the boiler
marked m¹. The upper end of the tube r, projecting through the cross-
head r, is furnished with a regulating cap, which has a hole through it for
the escape of steam. The stay rods s, s, are supported above by the brackets",
fixed to the pipe t, through which the steam from the valve t' is carried off.
The seating t, of the valve t¹, is fixed in the valve box s; the spindle of the
valve is acted upon by the rod r, fixed to the end of the tuber which
passes through the stuffing box s. The pipe is to carry off the water from
the tube r, and the pipe is to carry off the water from the pipe f. The
pipe q in Figure 1 which is fixed to the bracket m is in communication with
the pipe q, projecting from the tuber in Figure 4.
The mode of operation is as follows:-When the water in the boiler is at
its proper level, the lever n, see Figure 1, is held about horizontal by the
float n', and the valve p is kept closed by the spring coiled around its shank,
as already described, consequently no steam can enter the tube r, which
remains cool, and the valve t' is kept closed, as shewn in Figure 4, by the
pressure of the steam; but as soon as the water in the boiler descends to the
level below which it is unsafe to work, the float n' causes the lever n to
assume the position indicated by dotted lines; the valve p is then moved off
its seating by the projection. n*, acting on the shoulder of the valve p, and the

page_text: steam passing through the pipe to the tube r, heats this tube until it is
sufficiently elongated by expansion to force the valve 'off its seating; the steam
then makes its escape up the pipe t, as indicated by the arrows, and it may be
made to sound a whistle or other alarum, if necessary, to attract the notice of
the attendant. The steam will continue to blow off, until the level of the water
again rises sufficiently to allow the spring to close the valve p, when the tube r
in cooling will contract, and the steam acting on the valve ', again closes
it. I wish to remark that the pipe q may be brought from the tuber into
the boiler, the end of the pipe being open and placed at the level below which
it is considered unsafe to work; the steam entering the pipe q when the water
is too low, would, in this case, heat the tube r, as above described. I prefer,
however, the use of a float as being more certain in its action.
The last part of my Invention, which relates to the improved apparatus for
allowing steam to escape from the boiler, when the pressure thereof is greater
than desirable, is shewn in Figures 3, 4, 5, and 6, the latter view being an
elevation, partly in section, of part of my improvements. In Figures 3 and 6,
u is the ordinary glass tube to indicate the level of the water in the boiler;
and is a mercury guage of the usual construction; to the lower end of the
mercury guage is connected the pipe , the lower portion of which with the
tube of the mercury guage form a syphon. The tube v, after rising the
required height (which depends upon the pressure at which the steam is
worked) is bent down, and the end is secured to the top of the vessel v', to
which a second pipe 2 is secured; this second pipe is connected to the tube r,
as seen best in Figure 3. Between the vessel and the mercury guage
is a three-way tap w. This apparatus acts in the following manner:-When
the boiler to which my improved apparatus is applied is at work, the pressure
on the steam is indicated as usual by the mercury guage; if it is decided to
work the steam up to thirty-five pounds pressure on the square inch, then the
mercury must be at the bottom of the guage when that pressure is attained, and
the pipe must then be about seventy inches in height, so that when the steam
exceeds the said pressure, the mercury is forced out of the guage, through the
pipe v, and into the vessel . When all the mercury has passed into the
vessel ', the steam from the boiler is at liberty to pass through the pipes v
and 3, to the tube r, which it heats and expands, thereby forcing the valve t',
see Figure 4, off its seating and allowing the steam to blow off. When the
pressure in the boiler is sufficiently reduced, the attendant, by turning the
handle w¹, see Figure 3, moves the three-way tap w, until the passage between
the vessel and the mercury guage is opened; the mercury then drops into
the mercury guage, and the tap w is brought again into the position shewn

page_text: in Figure 6, consequently the steam in the boiler is then brought to act on
the mercury, which shuts off the communication between the boiler and the
tube r; this tube then cools, and in contracting allows the valve t' to be closed
by the steam. The steam in escaping from the vessel v¹, may be made to
sound a whistle or other alarum, instead of being conveyed to the tuber as
above described; by this means the mercury guage would answer as safety
valve possessing this advantage, that when the mercury was collected in the
vessel v', the steam would be able to escape without the resistance offered by
safety valves of the usual construction.
Having thus stated the nature of my Invention, and described the best
means with which I am acquainted for carrying the same into operation, I
wish it to be understood that I do not limit myself to the details set forth;
but what I claim is,-
First, the improved apparatus shewn and described in reference to Figures
1 and 2, for regulating the supply of feed water to steam boilers.
Secondly, the improved apparatus shewn and described in reference to
Figures 1, 3, 4, and 5, for giving notice when the water of a steam boiler
descends below a certain level, or any combination of parts for effecting the
same object by the expansion or contraction of a metal tube or rod.
Thirdly, the improved apparatus shewn and described in reference to
Figures 3, 4, 5, and 6, for allowing steam to escape when the pressure in the
boiler exceeds the required limits, or any combination of parts for effecting
the same object by the expansion or contraction of a metal tube or rod.
And lastly, the improvements in mercury guages, shewn and described in
reference to Figures 3 and 6, by which the mercury, when forced out of the
indicating tube, is collected in a vessel, and the steam is then at liberty to
escape.
In witness whereof, I, the said Thomas Greenhalgh, have hereunto set my
hand and seal, this Seventeenth day of January, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witness,
H. B. BARLOW,
Manchester.
THOMAS GREENHALGH. (L.S.)