IMPROVEMENTS IN SAFETY VALVES
Year: 1876

page_text: LETTERS PATENT to John Dickinson, of the Palmer's Hill Engine Works,
Sunderland, in the County of Durham, for the Invention of "IMPROVEMENTS
IN SAFETY VALVES."
PROVISIONAL SPECIFICATION left by the said John Dickinson at the Office
of the Commissioners of Patents on the 12th July 1876.
JOHN DICKINSON, of the Palmer's Hill Engine Works, Sunderland, in the County
of Durham. "IMPROVEMENTS IN SAFETY VALVES."
This Invention has for its object improvements in safety valves.
I construct safety valves with the spring beneath the valve, and the valve spindle,
which is of Muntz metal, is let into a socket on top of the valve and passes down
through its centre. The valve is annular, and so also the valve seating, and the
steam space or passage immediately beneath. A brass bush is fitted into these
latter and continued down through and secured by a nut to make valve and seat
perfectly tight, and also to form a guide for the valve spindle. The spindle passes
through the centre of the coiled spring and receives at its lower end a long nut
having a loose flange on which the spring abuts. The spring can be compressed
more or less to vary the spring pressure on the valve by screwing this nut on the
spindle. The nut can be locked in any position by a plug screwed into its end,
where it projects below the spindle. The spring is enclosed in a spring box, and
from its position is but little liable to be brought into contact with and corroded by
the steam. As a further precaution, however, and to intercept any steam which
may pass down around the valve spindle I arrange a telescopic tube within the
spring and around the spindle. One portion of the telescopic tube is in steam-
tight connection with the bush on bottom and the other with the flanged nut upon
the spindle. The small quantity of steam which may pass down around the valve
spindle will condense within the telescopic tube and will drain off at the bottom.
The annular valve is provided with overhanging lips, on which the steam acts as
soon as the valve commences to open, this ensures the rise of the valve at once to a
height sufficient to give ready escape to the steam.
The valve spindle extends up above the valve into a cap at the top of the valve
box, and this cap can be turned by a hand wheel, crutch, or handle formed upon it.
In this way the valve can be turned round on its seat to remove any grit that may

page_text: have become deposited on its face, there being a key passing through the cap and
through an elongated hole in the valve spindle. By means of a lever the cap can
be lifted at pleasure, and thus the valve is raised from its seat; when it is desired
to give free vent to the steam by removing the cap a temporary weight or lever
may be applied to top of spindle and spring charged if broken, or new one put on,
without the necessity of blowing off the steam.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Dickinson in the Great Seal Patent Office on the 12th January
1877.
JOHN DICKINSON, of the Palmer's Hill Engine Works, Sunderland, in the County
"IMPROVEMENTS IN SAFETY VALVES."
of Durham.
This Invention has for its object improvements in safety valves.
I construct safety valves with the spring beneath the valve, and the valve spindle,
which is of Muntz metal, is let into a socket on the top of the valve and passes
down through its centre. The valve is annular, and so also is the valve seating and
the steam space or passage immediately beneath. A brass bush is fitted into. these
latter and continued down through and secured by a nut to make valve and seat
perfectly tight, and also to form a guide for the valve spindle. The spindle passes
through the centre of the coiled spring and receives at its lower end a long nut
having a loose flange on which the spring abuts. The spring can be compressed
more or less to vary the spring pressure on the valve by screwing this nut on the
spindle. The nut can be locked in any position by a plug screwed into its end
where it projects below the spindle. The spring is enclosed in a spring box, and
from its position is but little liable to be brought into contact with and corroded
by the steam. As a further precaution, however, and to intercept any steam which
may pass down around the valve spindle I arrange a telescopic tube within the
spring and around the spindle. One portion of the telescopic tube is in steam-tight
connection with the bush on the bottom and the other with the flanged nut upon
the spindle. The small quantity of steam which may pass down around the valve
spindle will condense within the telescopic tube and will drain off at the bottom.
The annular valve is provided with overhanging lips, on which the steam acts as
soon as the valve commences to open; this ensures the rise of the valve at once to a
height sufficient to give ready escape to the steam.
The valve spindle extends up above the valve into a cap at the top of the valve
box, and this cap can be turned by a hand wheel, crutch, or handle formed upon
it in this way the valve can be turned round on its seat to remove any grit that
may have become deposited on its face, there being a key passing through the cap
and through an elongated hole in the valve spindle. By means of a lever the cap
can be lifted at pleasure, and thus the valve is raised from its seat when it is
desired to give free vent to the steam. By removing the cap a temporary weight
or lever may be applied to the top of the spindle and the spring changed if broken,
On Sheet 1
or a new one put on, without the necessity of blowing off the steam.
Figure 1 shews a vertical section, and Figure 2 an elevation partly in section of a
pair of valves arranged as above desciribed; Figure 3 is a horizontal section
through the valve chamber; Figure 4, a cross section taken through one of the
springs; and Figure 5 is a partial plan view.
A is the cap for lifting and turning the valve on its seat; B is the key for locking
the cap to the spindle; B¹ is a hole formed through the key B, to allow of this key
being retained by a padlock; C is a lever for lifting the valve; it embraces lugs
which project from a ring D that is divided into two halves; E is the valve
chamber, and F the branch outlet for waste steam; G is the valve spindle passing
downwards through a bush H which forms a guide for it; I is the valve on the

page_text: valve spindle and J its annular seat; K is a steam chamber below the annular
valve seat; L is a steam branch from this chamber to fit on to the top of the
boiler. The dotted lines M shew also how the steam chamber K may be formed
with a branch to fit on to the side of a steam dome. N is a cup for holding the
valve spring 0; P, is the telescopic casing round the valve spindle to prevent steam
getting to and injuring the spring; Qare drain holes from the bottom of this
casing; R is the nut for adjusting the compression of the spring, and S is the check
nut for the same; T is the keyway formed in this check nut, to allow of its being
turned; U, U, are the casings for the springs. The construction of the different
parts of the valve is clearly shewn in the Drawing, so that it is unnecessary to
give any further detailed description of it.
The advantages derived from constructing safety valves in the manner above
described are as follows:-The valve being annular and having two faces for the
escape of steam it will be sensitive and blow off rapidly when raised, and thereby
contribute to the safety of a steam boiler. The valve spindle G being carried up
through the top of the valve chamber or box, and being taken hold of by a cap A,
the valve can be turned on its seat to remove any grit that may have settled
between them. The spring O being below the valve seat and steam chamber
steam may be got up and the valve tested and defects, if there are any, remedied
before fixing the bottom casing which encloses the spring or the top casing over the
valve. The arrangement also prevents any waste steam from getting to the springs,
as the steain before it can get to the spring must pass down between the valvo
spindle and bush H, whereby it is condensed, and flows off through holes Q in cup N
and casing U. The telescopic tube P also serves as a further protection to impede
escaping steam from coming into contact with the spring. Another advantage in
the arrangement is that in the event of a broken spring the top cap A can be taken
off and the valve spindle be weighted until a new spring has been put on, and this
may be done in a few minutes without, as at present necessary, blowing down the
steam.
The compression of the spring O can readily be adjusted, and when the proper
pressure has been put upon the valve the nut R can be locked by the check nut S,
and the key for turning this nut can then be given in charge of the responsible
official.
On Sheet 2 is shewn a modification of the valve. In this modification one spring
only is employed for the pair of valves in place of a separate spring for each
valve.
Having thus described the nature of my Invention, and the manner of performing
the same, I would have it understood that I claim the improvements in the con-
struction of safety valves substantially as herein described.
In witness whereof, I, the said John Dickinson, have hereunto set my hand
and seal, this Ninth day of January, in the year of our Lord One thousand
eight hundred and seventy-seven.
TATTIT
JOHN DICKINSON. (L.S.)