Improvements in Steam Stop Valves.
Year: 1896

page_text: Date of Application, 10th Nov, 1896-Accepted, 20th Mar., 1897
COMPLETE SPECIFICATION.
Improvements in Steam Stop Valves.
We, ROBERT MCLAUGHLIN, Mechanical Engineer, residing at No. 111 North
Sixteenth Street, in the City of Philadelphia, County of Philadelphia, State of
Pennsylvania, and United States of America, and WILLIAM MCLAUGHLIN,
Mechanical Engineer, residing at No. 2560 Cedar Street, in the City of
Philadelphia, County of Philadelphia, State of Pennsylvania, and United States
of America, 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:-
The object of our invention is to provide simple, efficient, and reliable means
for effecting, at a point more or less remote from a valve controlling the delivery
of steam from a boiler to an engine or other medium of utilization, the instantaneous
closure of said valve upon such sudden and abnormal reduction of pressure in the
delivery pipe leading therefrom as would be caused by the escape of steam in
considerable volume upon a rupture of the pipe or its connections, or by a sudden
and material release of load or resistance, in the operation of an engine supplied
with steam by said pipe.
The improvement claimed is hereinafter fully set forth.
The essential features of our invention, generally stated, consist in a piston
which is connected to a stop or throttle valve governing a steam supply pipe
leading from a steam boiler to an engine, a steam heating apparatus, or other
medium or means for the utilization of steam, and which is normally subject to
pressure by which it is maintained in position to hold, or to permit the valve to
remain open during normal conditions of operation, but, upon a release of such
pressure, or equivalently, upon the application of greater opposing pressure, the
valve is instantly, directly, and positively closed by an opposing pressure, applied
either on the opposite side of said piston, or to a connected piston, in oppositely.
acting direction, as the case may be. The release of the pressure upon the piston
by which the valve is held open, or the application of greater opposing pressure,
is effected either manually or automatically; in the former case, by the opening
of an outlet or valve by an operator, which outlet or valve may be one of a
number, located at different desired and determined points, more or less remote
from the stop valve, whereupon the pressure on the opposite side of the piston
moves it into position in which it closes the connected stop valve. Automatic
release of pressure upon a piston by which a stop valve is held open, is effected by
the sudden and material reduction of pressure in the steam supply pipe on the
delivery side of the valve, (from which portion of the pipe the steam which acts
on the piston is taken) caused by unduly sudden release of loal of the engine,
whereupon higher boiler pressure, acting upon a second piston of smaller diameter,
connected to the stop valve in opposite direction to the piston by which the valve.
is held open, closes said valve.
In order to prevent injury to an operator by the escape of steam from the outlet
through which pressure is relieved from a piston to close the stop valve, which:
outlet may be afforded by breaking a frangible tube or plate, or displacing a
detachable plug provided for the purpose, such tube, plate, or plug, is enclosed in.
a pressure tight safety box, having a pipe leading to a proper point of discharge,

page_text: and any desired number of such safety boxes, or of pressure release valves, may
be employed, being located at points where they may be readily accessible and be
operated without exposure to escaping steam from a rupture of the steam pipe,.
which would render the stop valve inaccessible. The improvement thus constitutes
an effective safety appliance, in preventing loss of life or severe injury to engineers
and firemen, or others employed in the fireroom of a steam vessel or other closed
boiler compartment, by enabling the escape of steam from a ruptured steam pipe
to be instantly stopped, by the actuation of a simple and positively acting device,
at any one of a number of points located in such positions, and at such distance
from the stop valve-and steam pipe, as to be accessible without contact with, or
injury from, the escaping steam.
Our improvement is readily applicable to stop valves of the ordinary pattern,
without involving any material alteration thereof, and may also be applied for
closing the main injection valves or other sea valves of steam vessels.
In the accompanying drawings:
Figure 1 is a diagrammatic vertical longitudinal section through a steam vessel,
illustrating an application of our invention; Fig. 2, a similar transverse section;
Fig. 3, a similar section through a building, showing our invention applied in:
connection with the boilers thereof
Fig. 4, a vertical central section through a steam stop valve embodying our
invention; Fig. 5, a similar section taken at a right angle to Fig. 4;
Fig. 6, a view, partly in elevation and partly in section, of a safety box;
Fig. 7, a similar view of a steam stop valve, illustrating a structural modification
of our invention; Fig. 8, a similar view of the same, taken at a right angle to
Fig. 7;
Fig. 9, a vertical central section through a stop valve, illustrating a further
structural modification; Fig. 10, a view, partly in elevation and partly in section,
of the same, taken at a right angle to Figure 9;
Fig. 11, a front view, in elevation, of the safety box of Fig. 10;
Fig. 12, a front view, in elevation, illustrating a modified form of safety box;
Fig. 13, a longitudinal central section through the same;
Fig. 14, a view, partly in elevation and partly in section, of a portion of a steam
pipe, illustrating the application of our invention with the employment of two
pistons; Fig. 15, a transverse section through the same, and,
Fig. 16, a side view, in elevation, of a steam engine, with the device of Figs. 14
and 15 applied on its steam pipe.
Referring first to Figs. 4, 5, and 6, our invention is shown as applied in
connection with a steain stop valve, which, in and of itself, is substantially of the
ordinary standard form, and is of the type known as a non return valve, the valve
proper being held in open position by the pressure of the steam in the boiler, and
closing by its own gravity when the pressure therein falls to or near that of the
atmosphere. The globular body 1, of the valve, is provided with inlet and outlet
passages 2, 3, having suitable flanges for connection to a boiler and to a steam
pipe, respectively, and is closed at top by a cap 4, having a central stuffing box 5.
Communication between the inlet and outlet passages 2 and 3 is controlled by a
lift or poppet valve 6, which seats on a ring or bushing 7, at the inner end of the
inlet passage 2, and which is connected, by a screw cap 8, to a central stem 9,
having handles 10 on its outer end. Except when held down to its seat by the
screwed stem and out hereinafter described, the valve 6 may be raised therefrom
by the stem 9, or by steam pressure in the inlet passage 2. Two parallel
columns 11, 11, are screwed into the body 1 and cap 4, and are connected at top
by a yoke 12, which is held in position by nuts 13, engaging threads on the upper
or outer ends of the columns. For convenience of construction, the collars 14,
against which the yoke bears, are made separate from the columns, which are
slightly reduced in diameter at and adjacent to their outer ends, to receive and
hold the collars against shoulders.

page_text: A cylinder or pressure chamber 15, having a circumferential flange 16 on its
outer end, and provided with a head 17, of substantially similar diameter to the
flange 16, is fitted to slide longitudinally on the columns 11, the flange 16 and
head 17 being recessed to fit thereon, as indicated by dotted lines in Fig. 4. The
inner end of the cylinder 15 is closed, and provided with a central tubular
extension 18, which passes through the stuffing box 5, of the valve body, and is
made of such length that when the cylinder 15 is brought to its lowest or
innermost position, the tubular extension will abut against the screw cap 8 of the
valve 6, and hold the latter against its seat 7. The cylinder 15 is fitted with a
properly packed piston 19, the diameter of which is greater than that of the
valve 6, and to which is fixed a tubular piston rod 20, which passes through the
tubular extension 18 and surrounds the stem 9 of the valve. The inner end of
the piston rod 20 is adapted to abut against the cap 8 of the valve, and it is made
of such length that when the piston is depressed to the inner extremity of its
traverse in the cylinder, the piston rod will force the valve 6 to, and hold it on,
its seat.
The cylinder 15 may be raised and lowered, and held in any determined position,
on the columns 11, in order to hold the valve 6 closed when required, or to limit,
as desired, the maximum elevation of the valve from its seat.
For this purpose,
the head 17, which is bolted to the cylinder, is provided with a tubular stem 21,
which surrounds the valve stem 9, and is externally screw threaded, its thread
engaging a nut 22, which is fitted to rotate in the yoke 12, and is connected to a
hand wheel 23. By rotation of the hand wheel in one or the other direction, the
cylinder may be raised or lowered as desired, and is held in adjusted position by the
engagement of the stem 21 and nut 22.
The piston 19 is normally held at the outer extremity of its traverse in the
cylinder, by being subjected, when in such position, to the pressure of steam from
the boiler upon a greater area on its inner than on its outer side.
The piston'
is made a differential one, in this instance, by forming a projecting ring 24
on its outer face, which ring is finished and fits truly against a corresponding
finished annular face 25, on the inner side of the head 17. Pressure on the
outer side of the piston, therefore, acts only on the smaller annular surface
thereof surrounding the ring 24, when the piston is at the outer extremity of
its traverse, while pressure on the inner side of the piston acts upon the
materially larger area surrounding the tubular piston rod 20.
We do not,
however, limit ourselves to a differential piston of the above specific construction,
and hereinafter describe another form by which the same result is equivalently
attained.
Steam from the boiler is supplied to the cylinder 15, on opposite sides of its
piston 19, by a pipe or pipes 26, a single pipe, with proper connections, being,
in this case, employed, and communication with the cylinder being effected
through telescoping pipes, in order to admit of the longitudinal movement of
the cylinder on the columns, without permitting the escape of steam. The
pipe 26 leads into a chamber 27, formed in the yoke 12, and a pipe 28, fixed
to the cylinder head 17, and passing through a stuffing box into the chamber 27,
supplies steam to the cylinder, ou the outer side of the piston 19. A similar
chamber 29, is fixed to the cap 4 of the valve body, and a pipe 30, fixed to
the inner end of the cylinder 15, passes through a stuffing box into the chamber 29.
The pipes 28 and 30 telescope into and out of the chambers 27 and 29, in the
movements of the cylinder, and thus maintain cominunication between the same
and the chambers, irrespective of the position, or condition of movement or
rest, of the cylinder.
The chamber 29 may communicate either directly or indirectly with the pipe 26,
or communicate directly with the boiler by an independent pipe, as preferred.
In the instance shown in Fig. 5, a branch pipe 31 is led from the boiler supply
pipe 26 into a chamber 33, in the lower part of which it opens by a contracted

page_text: nozzle 32. A partition 34, in which are formed openings or perforations having an
aggregate transverse area substantially equal to, or somewhat greater than, that of
the pipe 30, is fixed in the chamber 33, above the nozzle 32, and a pipe 35 is led
from the chamber 33, above the partition 34, to the chamber 29. Steam from the
boiler passes through the pipes 26 and 28 to the outer side of the piston 19, and
through the pipes 26 and 31, chamber 33, and pipes 35 and 30, to the inner
side of said piston, a free discharge being admitted from the inner side, when
required, by the perforations in the partition 34.
The release of pressure from the inner or lower side of the piston 19, is effected,
whenever the closure of the valve 6 is desired to be made by said piston, by
opening an outlet from a release pressure pipe 36, communicating with the
chamber 33, and, through said chamber and the pipes 35 and 30, with the
cylinder 15, on the inner side of the piston 19. The release pressure pipe 36 is
led to any desired point or points, (which may be more or less remote from the
stop valve), at which it may be deemed advisable or necessary to provide means
for closing the stop valve, and, at each of said points, it communicates with a
discharge pipe 37, leading to the atmosphere, to the condenser, or to any other safe
and convenient point of discharge. The release pressure pipe and discharge pipe
communicate either through a connecting pipe 38, governed by a release valve 39,
or through a normally closed passage, having a frangible or detachable member 40,
which may be a glass tube, as shown in Figs. 5 and 6, a disc, as shown in Fig. 10,
or a detachable plug, as shown in Fig. 13. Both of these pressure varying or
releasing devices, that is to say, a valve governed pipe, and a pipe having a
frangible or detachable member, may be applied at each point of desired actuation,
the special object of the latter device being to provide a means of release which
can be actuated with quickness and certainty by unskilled persons, who, in an
emergency, might not be able to properly operate a valve. The frangible or
detachable member 40 is preferably enclosed in a pressure tight safety box 41, in
order to prevent the operator from being scalded by the escaping steam, and is
broken er detached, as the case may be, by striking a slight blow upon a head 42,
fixed upon a pin 43, the opposite end of which abuts against the frangible or
detachable member 40. Upon the breakage or detachment of said member, an
outlet is immediately opened, through which pressure on the inner side of the
piston 19 is released, through the pipes 36 and 37 and their connections, and the
pressure on the outer side of the piston thereupon depresses said piston and closes
the valve 6.
As shown in Figs. 1 and 2, the pressure varying or releasing devices may
be located in various positions in a steam vessel, as in the engine room, fire
room, pilot house, and different points on the several decks. Fig. 3 shows the
releasing devices in the engine room, fire room, and each of the different stories of
a building. It will also be seen from these figures that by connecting the pressure
release pipes of the stop valves of a battery or set of boilers, the simultaneous
closure of the stop valves of all the boilers will be effected..
The construction shown in Figs. 7 and 8 operates similarly to that shown in
Figs. 4, 5 and 6, and above described, and differs therefrom only in the form of
the differential piston 19, which in this case is that of a frustum of a cone, the
pressure chamber 15, which corresponds, in function and relation to other members,
with the cylinder 15 before described, corresponding in form with the piston. The
piston 19 is provided with expansible packing rings 45, which fit in circumferential
grooves in the piston, and are maintained in contact with the surface of the pressure
chamber 15, by steam which is admitted behind them, from the space above the
piston, through passages 44, leading into the packing ring grooves. By the contact
of the expansible packing rings 45 with the pressure chamber, which is thus
maintained in all positions of the piston, it is made differential, and, as in the
instance first described, subjected, when in normal position, to pressure upon a
larger area on its inner than on its outer side. The pipe connections employed

page_text: in this construction may be similar to those shown in Fig. 5, and before
described.
In the modification shown in Figs. 9 and 10, the piston 19 is, as in the preceding
instance, normally subject to an excess of pressure on its inner side by which it is
maintained at the outer limit of its traverse. The inward stroke of the piston, by
which the closure of the valve 6 is effected, is, however, in this case, produced by
the admission of steam to the cylinder 15 on the outer side of the piston, instead of
by its release from the inner side as in the preceding instances, and the outward
pressure on the piston is afforded by a spring. The cylinder 15 is open at its inner
end, and is provided with legs or standards which are bolted to the cap 4 of the
valve body 1. A. short stem 46, is formed on or fixed to the lower side of the
valve 6, and moves in a guide 47, fixed in the inlet passage 2. A piston rod 48,
secured to the piston 19, passes through the stuffing box 5, of the valve body, and
is connected, at its lower end, to the valve 6. A helical spring 49, which surrounds
the piston rod 48, abuts against the inner side of the piston 19, and against a stop
fixed to the inner end of the cylinder, the tension of said spring being such as to
normally hold the piston at the outer limit of its traverse, in which position the
connected valve 6 will be fully open. To enable the valve 6 to be closed, or its
lift limited, when and as required, a stem 50 passes through a stuffing box in the
cylinder head 17, and abuts against the piston when at the outer limit of its
traverse, said stem being threaded to engage a nut in the yoke 12, which, in this
case, is fixed to the cylinder, and carrying a hand wheel 51. By the rotation of the
hand wheel, the piston and connected valve 6 may be pressed downward until the
valve is brought to its seat, or for such shorter distance as will limit the lift
of the valve to any desired degree.
The pressure supply pipe 26 leads from the boiler into the outer end of the
cylinder, and a safety box 40 is interposed between two sections of said pipe.
Communication between the sections of pipe on opposite sides of the safety box is
normally cut off by a frangible member 40, which, in this instance, is in the form of
a plate or disc closing a port or passage way through the safety box. The plate 40
may be broken by a blow on the head 42, of a pin 43, which passes into the safety
box and abuts against the plate 40. Upon the fracture of the plate 40, steam is
admitted to the outer side of the piston 19, and by its pressure thereon, forces the
piston downwardly and seats the connected valve 6, as in the instances before
described.
Figs. 12 and 13 show a form of safety box in which communication is established
between the release pressure pipe 36 and discharge pipe 37, to release the pressure
from the inner side of the piston, in the constructions of Figs. 4, 5, 7, and 8,
by displacing a detachable member having the form of a plug 40, which closes the
opening of the pipe 36 to the safety box 41. The plug 40 normally rests on a
block 53, which is preferably provided with an elastic bearing, and which may be
adjusted to hold the plug properly in position by a set screw 54. The detachment
of the plug is effected, when immediate closure of the stop valve is desired, by
striking a slight blow on the head 42 of the pin 43, which abuts against the plug 40,
and pressure is thereby released from the inner side of the piston, through the
pipes 36 and 37, as before described.
Figs. 14, 15, and 16, illustrate our invention as applied to effect the closure of a
valve 57, controlling the steam supply pipe 55, ef a steam engine 56, so as to
immediately and automatically shut off the supply of steam to the engine, in the
event of a sudden and abnormal decrease of the load of the latter, and thereby
prevent the damage resultant upon the engines "running away," which is liable to
occur in such case. The construction will also effect the closure of the valve, in
the event of the bursting of the steam pipe on the side of the valve towards the
engine. The valve 57, which is of the butterfly type, is journalled transversely to
the steam pipe 55, and a double armed lever 59 is fixed on the projecting end of one
of its journals. A cylinder 15, provided with a piston 19, is journalled to the steam
pipe, on one side of the axis of the valve 57, and a cylinder 15, of smaller

page_text: -diameter and fitted with a piston 19, is journalled to the steain pipe on the opposite
side of the axis of the valve. The piston rod 48, of the cylinder 15, is coupled to
one of the arms of the lever 59, and the piston rod 48, of the smaller cylinder 15*,
is coupled to the other arm of said lever. Steam from the boiler is supplied to the
cylinder 15, by a pipe 26, and the cylinder 15 is connected, by a pipe. 58, with the
steam pipe 55, at a point near the engine. The pipes 26 and 58 are made
sufficiently flexible, or are jointed, as to permit of the vibration of the
cylinders 15 and 15* upon their pivots or trunnions, when required, without leakage
of steam.
SO
The pressure of the steam upon the piston 19, of the cylinder 15, is normally
greater than that upon the piston of the cylinder 15, owing to the larger area of
the former, and forces the piston 19 to the outer limit of its traverse, in which
position it holds the connected valve 57 open, and permits a free flow of steam,
through the nipe 55, to the engine. When, however, the pressure in the steam
pipe, on the side of the valve nearer to the engine, is suddenly and materially
reduced, as by an abnormal increase in the speed of the engine, or by the bursting
of the pipe, the then greater pressure in the pipe 26, acting on the piston 19ª, of the
cylinder 15, moves said piston outwardly, against the diminished resistance of
the pressure on the piston 19, and iminediately closes the valve 57, shutting off the
supply of steam to the engine, or to the ruptured portion of the steam pipe, as
the case may be.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
1. The combination of a valve for controlling the flow of fluid through a pipe,
two pistons which are normally and coincidently subject to pressure upon unequal
areas respectively, rods connected to said pistons and adapted to impart the
differential pressures acting thereon, in opposite directions, to said valve, and
means for applying a preponderance of pressure to the smaller piston area.
2. The combination of a valve for controlling the flow of fluid through a pipe, a
piston which is normally subject to unequal pressures on opposite sides, a rod
connected to said piston and adapted to impart pressure to said valve, a normally
closed pipe through which a variation of the degree of pressure on one side of said
piston may be effected, and a frangible or detachable member for opening
communication through said pipe.
3. The combination of a valve for controlling the flow of fluid through a pipe,
a piston which is normally subject to unequal pressures on opposite sides, a
rod connected to said piston and adapted to impart pressure to said valve, a
normally closed pipe through which a variation of pressure on one side of said
piston may be effected, a frangible or detachable member for opening communication
through said pipe, and a pressure tight safety box enclosing said frangible or
detachable member.
4. The combination of a valve for controlling the flow of fluid through a pipe, a
piston which is normally subject to unequal pressures on opposite sides, a rod
connected to said piston and adapted to impart pressure to said valve, a normally
closed pipe through which a variation of the degree of pressure on one side of said
piston may be effected, and a series of frangible or detachable members for opening
communication through said pipe at any one of a number of points variously
located relatively to the valve.
5. The combination of a valve for controlling the flow of fluid through a pipe, a
differential piston mechanism, which normally permits the valve to remain open, and
means for effecting the closure of the valve by said differential piston mechanism by
changing the direction of preponderance of pressure thereon.
6. The combination of a valve for controlling the flow of fluid through a pipe, a
cylinder or pressure chamber fitted to traverse towards and from said valve on
guides on the body or casing thereof, a differential piston fitting said pressure.

page_text: chamber and held normally by pressure therein in position to permit the valve to
be open, a rod on said differential piston extending into the valve body and adapted
to impart pressure to the valve, pipes for the supply of fluid under pressure to
opposite sides of said differential piston, and means for releasing pressure from the
larger area of said differential piston.
Dated i
D
daw of Databan
Witnesses:
J. SNOWDEN BELL,
ALEXANDER BYERS,
As to Robert M Laughlin.
MARK MCLAUGHLIN,
JAMES MCLAUGHLIN,
As to William M.Laughlin.
ROBERT MCLAUGHLIN.
WILLIAM MCLAUGHLIN..