IMPROVEMENTS IN SPRING SAFETY VALVES
Year: 1881

page_text: LETTERS PATENT to Thomas Adams, of West Gorton, Manchester, in the
County of Lancaster, Engineer, for an Invention of "IMPROVEMENTS IN
SPRING SAFETY VALVES."
PROVISIONAL SPECIFICATION left by the said Thomas Adams at the Office
of the Commissioners of Patents on the 23rd March 1881.
THOMAS ADAMS, of West Gorton, Manchester, in the County of Lancaster,
Engineer. "IMPROVEMENTS IN SPRING SAFETY VALVES."
This Invention has for its object improvements in spring safety valves.
In order to provide for a free escape of steam from marine and other boilers of
large dimensions should the pressure of steam get too high, I employ four valves
ranged in a square, and each opening upwards into one chamber above them. The
spindles which hold these valves down on to their seats pass up through the top of
the chamber into another chamber, in which each spindle is surrounded by a
coiled spring which serves to hold down the valve in the usual way. The lower
chamber is divided into two or more compartments by vertical partitions which
pass from one side of the chamber through its centres, and extends a short distance
into a side outlet passage which is provided from the chamber. The partitions
pass between the valves so that there shall be one or two valves in each com-
partment. Each valve is so formed that when it once lifts it opens wide in the
manner now well known.
By the above arrangement if any one or other of the valves in either compartment
lifts, the steam issuing from it escapes from that compartment through the side
outlet passage, and rushing past the end of the partitions before mentioned tends to
reduce the pressure of air upon the top of the valves in the other compartments,
and so permits them also to lift, and thus a very free escape for the steam is
afforded. For controlling the pressure of the springs used for holding safety
valves down on to their seats, the coiled springs which surround the valve spindles
are ordinarily made to rest against a cap, which is forced downwards by the lower
end of a hollow screw bolt or nut bearing upon it, whilst the spindle can rise or
fall freely through the bolt or nut. When the bolt has been screwed down

page_text: sufficiently to give the required compression to the spring, its head is made to
come down on to a stop formed of a loose ring through which the stem of the bolt
passes, and the pressure that can be put upon the spring is carefully adjusted by
making this ring of the thickness required.
Whenever the valves have to be tested, these rings are taken away and the
valves are tested without the rings being in place. When the valves have been
tested the rings have to be replaced, and to do this it is necessary to let down the
pressure of steam, then to take out the bolt, place the ring around it, and screw it
back into its place. The letting down of the steam pressure and afterwards again
getting up steam occupies considerable time, and often causes a steam vessel to be
delayed for a tide at starting.
'
1
According to my Invention I divide the ring into two or more pieces, which if
the bolt is slightly slackened can be slipped in under the head of the bolt, and can
then be embraced by a split spring ring, and be so clamped together around
the bolt, thus the ring stop can be put into and secured in place with but little
loss of time.
For spring safety valves of small size suitable for locomotives and for other
boilers I provide a cylindrical chamber above the valve seat; the cylinder at its
lower end has a screw thread cut around it internally, and screws onto the outer
circumference of the plate in which the valve seat is formed. The cylinder is open
at the top with the exception of a small central cap, which is carried by radial
arms from the side of the cylinder. The bottom of the cap I make to bear upon
the top of a casing within which is contained the spring by which 'the valve
spindle is forced downwards, so that by screwing the cylindrical chamber down-
wards more or less the pressure of the spring can be set to any pressure required,
and the cylindrical chamber can then be locked and prevented from being turned
by any suitable lock. The upper end of the valve spindle rises up into the cap,
sufficient space being left between the top of the spindle and the top of the cap to
allow of the valve lifting.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Adams in the Great Seal Patent Office on the
23rd September 1881.
THOMAS ADAMS, of West Gorton, Manchester, in the County of Lancaster,
Engineer. "IMPROVEMENTS IN SPRING SAFETY VALVES."
This Invention has for its object improvements in spring safety valves.
In order to provide for a free escape of steam from marine and other boilers
of large dimensions should the pressure of steam get too high, I employ four
valves ranged in a square, and each opening upwards into one chamber above
them. The spindles which hold these valves down on to their seats pass up
through the top of the chamber into another chamber, in which each spindle is
surrounded by a coiled spring, which serves to hold down the valve in the usual
way. The lower chamber is divided into two or more compartments by vertical
partitions, which extend a short distance into a side outlet passage which is
provided from the chamber. The partitions pass between the valves so that there
shall be one or two valves in each compartment. Each valve is so formed that
when it once lifts it opens wide in the manner now well known. An assemblage
of three valves may be arranged in a somewhat similar way.
By the above arrangement if any one or other of the valves in either com-
partment lifts the steam issuing from it escapes from that compartment through
the side outlet passage, and rushing past the end of the partitions before
mentioned tends to reduce the pressure of air upon the top of the valves in the
other compartments, and so permits them also to lift, and thus a very free escape
for the steam is afforded.
In this way I am able to use three or four valves of small diameter in place
of the pairs of valves of large diameter at present used on large marine and
other boilers.
Figure 1 of the Drawings hereunto annexed shews a sectional elevation, and
Figure 2 a plan partly in section of a group of four lock up safety valves combined
in one casing and constructed as above described.
A is the valve box containing the four valves, each divided from the other by a
division plate B; C are the seatings of the valves. Above them are the valves
each with a chamber D formed around them, so that if they once lift they open
wide, as is now well understood.
The division plates B enter the side exit A' from the valve box A, as shewn
at Figure 2, to serve the purpose above mentioned; E are the valve spindles,
where they pass up through the top of the chamber and enter the spring box
above it; a steam tight joint is formed by a packing ring F split into two halves,
and held together with a clip spring; in this way steam is prevented from entering
the spring box and corroding the springs; G are the springs, and H is a pintle
or sleeve extending up inside of each spring, the lower end of which is formed
into a collar on which the spring rests; should the spring break the pintle catches
it and prevents the broken ends from passing each other, and the spring
consequently performs its functions on the valve notwithstanding it may be
broken.
I is a plate or cover bolted to the top of the spring box; K are the compression
nuts screwed through brass bushes in the cover I, and which serve to compress the
springs and put the necessary load on the valves.
L is a check ring or metal washer which is fitted between the compressing nut K
and the plate I, to prevent any further load being put on the valve after it has
been adjusted to the required pressure..

page_text: M is the cap or top cover, and N are the levers for easing the valves; O are the
handles or sleeves which by means of the cottar P turn the valves round on their
seating as usual.
Figure 3 shews a horizontal section of assemblage of three safety valves in one
case A and separated the one from the other by division plates B led into the side
outlet A³ from the case in a similar manner to that above described with respect to
four valves, the object being the same, viz., that if one valve lifts the others shall
be likewise lifted. The arrangement is shewn by full lines, and a modification of
the arrangement by dotted lines.
One arrangement is shewn in full lines, and a modification of the arrangement in
dotted lines.
Another part of my Invention consists in forming the check rings L (used in
safety valves for preventing any further load being put upon the valves after they
have been adjusted to the required pressure) in two or more pieces, which if the
bolt is slightly slackened can be slipped in under the head of the bolt, and can
then be embraced by a split spring ring and be so clamped together around the
bolt; thus the ring stop can be put into and secured in place with but little loss
of time.
A ring stop so divided into two or more parts and held together by a split spring
ring clip is shown at Figure 1; L is the divided ring stop, and L', the split spring
ring for holding the parts of the stop together.
The thickness of the ring stop is as heretofore carefully adjusted, so that the
head of the hollow screw bolt or nut K may bear upon it when the bolt has been
screwed down sufficiently to give the required compression to the spring G, by
which the valve is held down on to its seat.
Whenever the valves have to be tested these rings have to be taken away, and
the valves are tested without the rings being in place.
When the valves have been tested the rings have to be replaced, and to do this
if a ring stop formed in one piece is used, as heretofore, it is necessary to let down
the pressure of steam, then to take out the bollow screw bolt, place the ring around
it, and screw it back into its place. The letting down of the steam pressure and
afterwards again getting up steam occupies much time, and often causes a vessel to
be delayed for a tide at starting. All these inconveniences are avoided by using a
check ring divided into two or more parts, as above described, and holding them
together by a split spring ring.
For spring safety valves of small size, especially suitable for portable locomotives,
and for boilers of small size, I provide a cylindrical chamber above the valve seat;
the cylinder at its lower end has a screw thread cut around it internally, and
screws onto the outer circumference of the plate in which the valve seat is formed.
The cylinder is open at the top with the exception of a small central cap, which is
carried by radial arms from the side of the cylinder. The bottom of the cap
I make to bear upon the top of a casing within which is contained the spring by
which the valve spindle is forced downwards, so that by screwing the cylindrical
chamber downwards more or less the pressure of the spring can be set to any
pressure required, and the cylindrical chamber can then be locked and prevented
from being turned by any suitable lock. The upper end of the valve spindle rises
up into the cap, sufficient space being left between the top of the spindle and the
top of the cap to allow of the valve lifting.
Figure 4 is a vertical section of a safety valve, constructed as above described.
A is the valve seating having a screw thread formed around its outer edge;
B is a cylindrical casing, the lower end of which screws on to this screw thread;
C is a central cup or boss at the top of the casing by means of which the requisite
load is put upon the valve D, as above described; E is the valve spindle, the point
of which is always below the mitre of the valve; F is a casing or pintle which
protects the spring G from corrosion, and also in the event of the spring breaking
acts in the same manner as the pintle before described. At the bottom of the
cylindrical casing B is a small flange H, and a corresponding flange is formed

page_text: around the seating A. When the valve has been adjusted to the required blowing
off pressure a check ring L is fitted in between the flanges; the flanges and check
ring are then locked by a small bolt K and padlock I, and in this
way any further
load is prevented from being put upon the valve.
Having thus described the nature of my Invention, and the manner of performing
the same, I would have it understood that I claim,―
First. The combination of an assemblage of three or four safety valves within
one casing divided into compartments by partitions extending to a side outlet
from the chamber, substantially as herein before described and illustrated in the
Drawing annexed.
Second. Forming the check rings L in two or more parts, and holding them
together by a split spring ring which is made to embrace them, substantially as
described.
Third. The construction of safety valves, substantially as herein before described
with reference to Figure 4.
In witness whereof, I, the said Thomas Adams, have hereunto set my hand
and seal, this Twenty ninth day of August, in the year of our Lord One
thousand eight hundred and eighty one.
THOMAS ADAMS. (L.S.)