A NEW OR IMPROVED COMBINED STEAM GAUGE AND SAFETY VALVE
Year: 1876

page_text: LETTERS PATENT to Edward Thomas Hughes, of the Firm of Hughes and
Son, Patent Agents, 123, Chancery Lane, London, for the Invention of
"A NEW OR IMPROVED COMBINED STEAM GAUGE AND SAFETY VALVE" A
communication from abroad by Nicolam Kaysser, of Hochet-on-the-Maine, and
August Kaysser and Johann Baptiste Helwig, both of Frankfort-on-the-Maine,
Germany.
Sealed the 20th March 1877, and dated the 23rd September 1876.
PROVISIONAL SPECIFICATION left by the said Edward Thomas Hughes at
the Office of the Commissioners of Patents on the 23rd September 1876.
EDWARD THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents,
123, Chancery Lane, London. "A NEW OR IMPROVED COMBINED STEAM GAUGE
AND SAFETY VALVE." A communication from abroad by Nicolam Kaysser, of
Hochet-on-the-Maine, and August Kaysser and Johann Baptiste Helwig, both of
Frankfort-on-the-Maine, Germany..
The object of this improved apparatus is to indicate the pressure of steam in the
boiler and to effect the automatic opening of a safety or discharge valve when the
pressure of the steam exceeds the prescribed limit, and also to close the said valve
when the normal or lower pressure is re-established. In carrying this into effect a
small cylinder is employed, in which is a plunger piston turned to exactly fit the
cylinder, and further provided with metal hoops or band packing to render same
thoroughly tight. The piston rod is continued beyond the cylinder head, and there
formed with teeth and provided at its end with an enlargement or bead, which
slides in a small cylinder. The steam or water (the latter under pressure like the
steam) enters through a small pipe above the piston to force same down.
The toothed portion of the piston rod gears with two segment pinions, the pivota
or arbors whereof carry counterweighted arms to act upon the piston in a contrary
direction to the steam or water.
The segment pinions make a quarter revolution on their axis, therefore the
weighted arms can be raised from a vertical to a horizontal position, and in this
latter position the pressure of the steam will be at its greatest. One of the segment
pinions has a cam arm or projecting piece, to which is pivoted a link rod jointed at

page_text: its extremity to one arm of a pivoted crank piece, the other arm of which crank
piece serves as an index finger or pointer, and traverses a dial plate divided to
indicate (in pounds or atmospheres) the pressure of the boiler.
I will now describe the valve, its connections, and working. When the steam or
water under pressure has reached its maximum, and acting upon the piston has
forced same down, the piston head acts upon a pin or stud in a hinged pice con-
nected to a slide valve rod, thereby drawing down the slide valve to open a port in
connection with and to admit steam to a cylinder, and in rear of a piston working
therein to actuate levers to open a valve in the steam boiler.
When the normal pressure is re-established the gauge piston is again raised
through the segment pinions, and weighted levers and a spring on the slide valve
rod will draw same back to close the valve and shut off pressure from the rear of
piston of safety valve levers.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Thomas Hughes in the Great Seal Patent Office on the 23rd
March 1877.
EDWARD THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents,
123, Chancery Lane, London. "A NEW OR IMPROVED COMBINED STEAM GAUGE
AND SAFETY VALVE." A communication from abroad by Nicolam Kaysser, of
Hochet-on-the-Maine, and August Kaysser and Johann Baptiste Helwig, both of
Frankfort-on-the-Maine, Germany.
The object of this improved apparatus is to indicate the pressure of steam in the
boiler and to effect the automatic opening of a safety or discharge valve when the
pressure of steam exceeds the prescribed limit, and also to close the said valve when
the normal or lower pressure is re-established.
In order that the incans for carrying this Invention into practical effect may be
clearly understood a Sheet of Drawings is hereunto annexed, illustrative thereof, and
reference is made in the following description to the figures and letters marked
thereon.
Figure 1 is a vertical section on line C, D, of Figure 2, and Figure 2 is a like
section at line A, B, of Figure 1. In a small cylinder F is arranged a piston or
plunger G turned to exactly fit the cylinder, and further provided with metal hoops
or band packing to render same thoroughly tight. The piston rod is continued
beyond the cylinder head, and there formed with teeth G¹, and provided at its end
with an enlargement or head G, which slides in a small cylinder F¹. The steam or
water (the latter under pressure like the steam) enters through a small pipe H
above the piston G and exerts its force thereon to force same down.
The toothed portion of the piston rod gears with two segment pinions C, C₁, free
to work on the pivots a, a, and said segment pinions carry arms I, I, counter
weighted as at B, B1, to act upon the piston G in a contrary direction to the steam
or water.
The segment pinions C, C¹, can make a quarter revolution on their axes, therefore
the weighted arms I, 1', can be raised from a vertical to a horizontal position, or in
the direction of the line a, as, Fig. 2, and in this latter position the pressure of the
steam will be at his greatest, that is, as represented in the Drawings, equal to eight
atmospheres. The distance a to a8 is eight times longer than the radius of the
segment wheel C. The line a, S, represents the centre of gravity of the lever I, and
is equal to line a, a³. The line a, as, is divided equally into eight parts, a, a¹ to
as, each of which divisions is of equal length to the radius of the segment C
(measured on the pitch circle). The oblique lines a¹, a², to a', repressed the
positions which the counterweighted lever I will occupy at the various increasing
or decreasing pressures; thus a, o, will be the position of the lever when the

page_text: pressure is at zero, because the centre of gravit S is vertically under the centre a,
and a¹ will be its position at one atmosphere, and so on.
It is clearly shewn that the counterweighted lever I is of a length, in a horizontal
direction, equal to a, a¹, for a pressure of one atmosphere, that is, its free end moves
that distance horizontally, and is also equal in the same sense to the radius of the
segment wheel C, and for two atmospheres is equal to twice the radius of C, and
for eight atmospheres is equal to eight times the radius of C, whilst the piston G
always acts upon the same lever arm, that is, the radius of C.
One of the segment pinions C has a cam arm or projecting piece N, to which is
pivoted a link rod N, P, jointed at its extremity P to one arm P of a pivotted crank
piece, P, Q, R, the other arm R of which crank piece serves as an index finger or
pointer, and traverses a dial plate T, divided to indicate (in pounds or atmospheres)
the pressure in the boiler.
I will now describe the valve, its connections, and working. When the steam
or water under pressure has reached its maximum, and acting upon the piston G
has forced same down, the piston head G acts upon a pin or stud g¹ in a hinged
piece t¹ connected to a slide valve rod t, thereby actuating the slide valve n to open
a port d leading and admitting steam from the slide valve chamber p through a
channel m to the cylinder E, and in rear of a piston D working therein. The valve
chamber P receives the steam from pipe H through the opening h. On the piston
D being raised it will actuate the lever x, x1, x2, and through it the safety valve M
communicating with the inside of the boiler.
When the normal pressure in the boiler is re-established the gauge piston G will
rise in consequence of the pressure thereon being removed and by reason of the
weighted levers I and toothed segment wheels C, C¹, acting on the toothed part G¹,
and pressure will also be removed from the stud 91, and the spring f will return the
slide valve to its original position. The steam and water under the piston D now
escapes through ports e, i, to the outside, piston D sinks down and the safety valve
M is closed. The mechanism is enclosed in a box L, L, which may be locked, so
that the engine man may not interfere with its working, and a small door v,
Figure 1, is provided in the boxing to allow of the parts being oiled. is a sheet of
glass for observation of the dial plato T; u, Figure 2, are studs or stops for levers
I, I, when said levers are acted upon by the maximum pressure. This mechanism
offers the advantage of quickly opening and with certainty and security a large
safety valve, the which cannot be rendered useless by improperly charging it.
Having now described the nature and particulars of the said Invention, I claim,-
First. The use of steam or fluid pressure upon levers fitted with weights instead
of springs, operated and working substantially as horein set forth.
Second. The automatic opening and closing of the safety or discharge valve of a
boiler by means of a steam or fluid worked piston D with its automatic gearing
and connections, substantially as herein described and shewn in the Drawings.
And, Third. The new or improved combined steam gauge and safety valve,
arranged and working substantially as herein set forth.
In witness whereof, I, the said Edward Thomas Hughes, have hereunto set my
hand and seal, this Twenty-third day of March, One thousand eight hundred
and seventy-seven.
E. T. HUGHES. (L.S.)