IMPROVEMENTS IN APPARATUS TO REGULATE THE PRESSURE OF FLUIDS, AND TO COMPENSATE FOR THE EXPANSION OF STEAM AND HOT WATER PIPES
Year: 1857

page_text: LETTERS PATENT to William Pratchitt and Samuel Horrocks, both of
Bolton-le-Moors, in the County of Lancaster, Engineers, for the Inven-
tion of "IMPROVEMENTS IN APPARATUS TO REGULATE THE PRESSURE OF FLUIDS,
AND TO COMPENSATE FOR THE EXPANSION OF STEAM AND HOT WATER PIPES."
Sealed the 29th January 1858, and dated the 13th August 1857.
PROVISIONAL SPECIFICATION left by the said William Pratchitt and
Samuel Horrocks at the Office of the Commissioners of Patents, with
their Petition, on the 13th August 1857.
We, WILLIAM PRATCHITT and SAMUEL HORROCKS, both of Bolton-le-Moors,
in the County of Lancaster, Engineers, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS TO REGULATE THE PRESSURE OF
FLUIDS, AND TO COMPENSATE FOR THE EXPANSION OF STEAM AND HOT WATER PIPES,"
to be as follows:-
The first part of this Iuvention is particularly applicable to regulate the
pressure of steam.
The apparatus consists of a mercury gauge, one leg of which projects
into the lower pressure side of a box containing a valve or valves. A float on
the mercury communicates with the valve or valves. The action is as.
follows: When the pressure of the steam falls below that required, in the
off-pipe, the mercury opens the valve or valves for the admission of steam

page_text: from the supply pipe. The contrary action takes place if the pressure in the
off-pipe increases beyond that required.
Our improvements in apparatus to compensate for the expansion of steam
and hot water pipes consist in the use of elastic wrought-iron or copper
chambers, so arranged on the steam or water pipes that the internal pressure
produced by expansion on the outer chamber is compensated by an inner
chamber. The two chambers are placed one within the other, the interior of
the inner one being open to the atmosphere, and its sides stayed to those of
the outer one in such a manner that the tendency of the pressure of the steam
or hot water to extend the sides of the outer chamber is neutralized by its
tendency to collapse those of the inner one.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Pratchitt and Samuel Horrocks in the Great Seal
Patent Office on the 12th February 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
PRATCHITT and SAMUEL HORROCKS, both of Bolton-le-Moors, in the County of
Lancaster, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of August, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said William Pratchitt and Samuel Horrocks, Her special licence
that we, the said William Pratchitt and Samuel Horrocks, our executors,
administrators, and assigns, or such others as we, the said William Pratchitt
and Samuel Horrocks, our 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 "IM-
PROVEMENTS IN APPARATUS TO REGULATE THE PRESSURE OF FLUIDS, AND TO
COMPENSATE FOR THE EXPANSION OF STEAM AND HOT WATER PIPES," upon the
condition (amongst others) that. we, the said William Pratchitt and Samuel
Horrocks, our executors or administrators, by an instrument in writing under
our, or their, or one of our or 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

page_text: Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that we, the said William Pratchitt and Samuel
Horrocks, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement (that is to say):--
The nature of our Invention of improvements in apparatus to regulate the
pressure of fluids consists in the application of a balanced valve to a mercury
guage, and the nature of our Invention of improvements in apparatus to com-
pensate for the expansion of steam and hot water pipes consists in the
introduction between such pipes of a compound chamber made of elastic
plates, and so united together that the internal pressure on the outer chamber
is balanced by the external pressure on the inner chamber.
And in order that our Invention may be fully understood and readily carried
into practical operation, we will proceed to describe the means pursued by us,
reference being had to the accompanying Sheet of Drawings, and to the
figures and letters marked thereon.
Figs. 1 and 2 are sectional elevations of an apparatus to regulate the
pressure of steam and other fluids to which our improvements are applied. a
is the mercury guage, of any required length, the mercury in which sustains
the float b, which acts by means of the rod and lever d upon the equilibrium
valve or valves c, the valve or valves being balanced by the weight e. By the
application of this balance weight the pressure of the steam or other fluid
passing through the inlet pipe f to the outlet pipe g can be more accurately
regulated than by the apparatus hitherto employed.
Fig. 3 is a sectional elevation of our improvements in apparatus to com-
pensate for the expansion of steam and hot water pipes; Fig. 4 is an external
view of the same; Figs. 5 and 6 represent similar views of a modification of
this part of our Invention; and Fig. 7, a vertical section of the same.
In Figs. 3, 4, 5, 6, and 7, h, h, are short pipes, connecting the apparatus
with the main range of piping; i, i, are the thin elastic plates forming the
outer chamber; and k, k, are those forming the inner chamber; 1, 1, are stays,
connecting the inner and outer chambers together. In Fig. 3, m is a small
pipe, forming a communication between the internal chamber and the atmo-
sphere. In the form of apparatus shewn in Figs. 5, 6, and 7, this pipe m
is not required, the atmosphere having free access between the sides of the
internal chamber, as shewn in the section, Fig. 7.
The compound chambers above described possess great advantages over the
single chambers hitherto employed to compensate for the expansion of steam

page_text: and hot water pipes; the atmosphere being admitted to the interior of the
internal chamber of our improved apparatus, and the internal chamber being
stayed to the external one, it is evident that the pressure of the steam or hot
water between the internal and external chambers is neutralized.
Having thus particularly described the nature of our Invention, and the
manner of performing the same, we declare that we claim,―
First, the application of a balanced valve to a mercury guage when used
to regulate the pressure of fluids, as shewn and described in reference to
Figs. 1 and 2.
Secondly, the improved compound chambers shewn and described in
reference to Figs. 3, 4, 5, 6, and 7, when applied to steam and hot water
pipes to compensate for the expansion thereof, or any modification of the
same.
And, lastly, the so constructing apparatus to compensate for the expansion
of steam and hot water pipes that the interior thereof shall be open to the
atmosphere.
In witness whereof, we, the said William Pratchitt and Samuel Horrocks,
have hereunto set our hands and seals, this Tenth day of February, in
the year of our Lord One thousand eight hundred and fifty-eight.
TY T
DD OCHLYTA
WILLIAM PRATCHE
(w.s.)
SAMUEL HORROCKS.
(L.S.)