Improvements in Recording Pressure-gauges.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Recording Pressure-gauges.
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this invention which has been com-
municated to me from abroad by Jarvis Bonesteel Edson of the City County and
State of New York United States of America and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
The object I have in view in these improvements is mainly to enhance the
adaptability of the gauge for recording and to render possible a reduced cost of.
construction.
Modern engineering employs greater pressures than were common a few years since
and in providing a recorder suitable thereto it has been found necessary to employ a
number of thin springs, or discs, to resist the great strain to which any form of
diaphragm is subjected. In order to secure greater sensitiveness and durability it is
important to obtain the utmost travel, or displacement, per unit of diameter of the
disc, and for the purposes for which the instrument is designed, it is equally necessary
to employ this travel with as little multiplication as possible of levers, gears, &c.
owing to the difficulties arising from loss of motion inherent in the construction, or
subsequently occasioned by wear, as well as to employ such method of construction as
shall enable a spring or disc to transmit its full travel with a minimum of friction.
Furthermore, when high pressures of dangerous fluids, or gases, are to be recorded,
it is highly important to provide against the serious results which would follow in
case of rupture of any of the diaphragms, due to overpressure, or fatigue of metal.
It is furthermore desirable to be able to control these pressures within certain limits,
by the sounding of electrical alarms, either on the instrument, or at a distance, when
certain limits of pressure are exceeded, or when pressure falls below prescribed limits.
It is further important that these alarms be susceptible of ready adjustment to these
different pressures, and also that when so adjusted, or set, to any given limits of
pressure, they may be easily tested from time to time, in order to ascertain whether
the battery, wires, or bells, are in proper condition, without changing or disturbing
the adjustment of these circuit closers.
To provide for the accomplishment of these results, I place either one or more
tempered steel corrugated convex diaphragm springs beneath the circular base, the
said springs being so placed as to receive the fluid pressure against the convex surface
of the diaphragm.
By convexing these corrugated diaphragm springs and causing the pressure to act
against the convexed side I am enabled to restrict the travel of the spring during its
early movement, resulting in giving more travel and sensitiveness as the diaphragm
distends until a point is reached at which it begins to rapidly slow down with the
motion of each additional equal increment of pressure. This is an important matter
in a recording gauge, of limited travel, and limited width of chart, particularly when
designed for high pressures.
In order to secure greater sensitiveness and durability where extreme high-pressures
are to be resisted, I employ a number of these convex diaphragms, corrugated as
described, and in order to provide against the action on the spring exposed to the
Buid, which is often caused by galvanic action, I place beneath the lower spring a
thin flexible lining or sheathing, say of copper, or an alloy of copper, so that the fluid
under pressure cannot reach the steel diaphragms. In order to provide against the
danger which might be caused by the bursting of one or more of these diaphragms,
if in so doing it allowed the fluid or gas to escape, I place either below, or between
the tempered steel diaphragmns a soft metal one, corrugated, the same as the remainder,

page_text: but left untempered, so as to be tough and yielding, but having less rigidity than
those which are tempered. To further provide against accidents which might be
caused by the escape of the imprisoned fluid, or liquid under pressure, I fill in the
space above the spring or springs in such manner that when the springs have been
distended to the full extent to which they are intended for the instrument, the action
of any further pressure tending to further deflect them, will be resisted by the metal
of the base. This is accomplished in various ways, but the one which I prefer, is to
fill in with soft metal having a low fusing point or cement or other suitable substance
while the pressure holds the spring deflected to its full range. Another method, which
works well in practice, is to make a plaster cast while the springs are under pressure,
and then remove it; then make a metal cast from the same.
In order to simplify as far as possible the movement transmitting mechanism of the
gauge, I make use of a multiplying lever which is in effect through a suitable
connection joined directly to the diaphragm-spring-or upper diaphragm spring, if
more than one be used; and to this multiplying lever I attach a marking arm which is
flexible, or has a flexible connection with the lever, so that during the vibrations of
the lever, the said arm may move up and down while maintaining contact with the
paper on which its movements are recorded. The details of this mechanism together
with those of the mechanism for the electrical alarm, as well as those of the other
improvements herein before referred to, can however best be explained and understood
by reference to the accompanying drawings in which I have represented a pressure
gauge embodying my said improvements in their preferred form.
In these drawings
Figure 1 is a front elevation of the instrument with the base in section.
Figure 2 is a side elevation of the mechanism above the base.
Figure 3 is a bottom view or plan of the same.
Figure 4 is a perspective view on an enlarged scale of the multiplying lever and
parts immediately connected therewith.
Figures 5, 6 and 7 are diagrammatic views hereinafter more particularly
referred to.
In this gauge I may employ one or more tempered diaphragm springs; said
springs being convex and corrugated and so placed as to receive the fluid pressure
against the convex surface of the diaphragm.
In the drawing I have shown two of such diaphragm springs--similar in a general
way to the like part in my United States Patent No. 174,125 of February 29th,
1876.
A is the base of the instrument chambered or recessed at C; and D are two sheet
steel corrugated diaphragm-springs bunched together in the chamber or recess and
secured at their edges to the base in the customary way by the shell E, which clamps
the said edges and is fastened in place by bolts a passing through the flange of the
shell and the intervening edge of the diaphragm-springs into the base.
The diaphragm springs are convex and corrugated as shown, and are so placed,
that the pressure of the fluid entering through the port or duct in the shell will be
exerted against the convex side of the said bunched diaphragm-springs.
Below these two tempered diaphragm-springs and bunched with them is a similarly
corrugated soft metal untempered plate or diaphragm D¹ for the purpose herein before
mentioned; and below the diaphragm D₁ is a thin flexible sheathing D³, of copper,
brass or the like to prevent danger of the injurious corroding action which might take
place were the diaphragms exposed to direct contact with the fluid.
Above the upper diaphragm is a metal filling or backing D3 which is intended to
resist further deflection of the springs after they have been distended to the full
extent to which they are intended for the instrument. This backing in the
particular shape represented in the drawing is a soft metal backing which is
formed by first distending the springs to the full extent; and then, while main-
taining them in this position, running into the base above the springs, a soft metal
having a low fusing point. This backing when it cools and solidifies, is in effect
a counter-part casting of the upper surface of the diaphragm spring. The backing

page_text: however can be formed in other ways, as for example by casting the iron base A a
little full on the underside, and then turning this full underside down into suitable
shape to form the backing; or by proceeding to form it in any of the ways herein-
before adverted to; what is essential is that there shall be for the diaphragm-
springs a backing which after the said diaphragm-springs have been distended to a
predetermined extent will resist their further deflection.
Upon the base A, and a suitable frame B erected thereon, are supported the various
parts of the recording and electrical alarm mechanisms.
The instrument is provided as usual with the customary spools or reels K¹ K² from
one to the other of which the strip of paper K passes over an intervening portion of
the frame on which there is a fixed vertical scale K³ to indicate the different pressures.
The strip or paper passes behind the scale between it and the frame; and the said
strip as usual is ruled with parallel lines to correspond with the divisions on the
scale.
The paper as it unwinds from one spool is wound upon the other-the spools for
this purpose being driven by a chronometer mechanism as usual. This actuating
mechanism I have not deemed it necessary to illustrate, as it forms no part of my
present invention. One such mechanism for the purpose is set forth in my United
States Patent No. 174, 125, herein before referred to.
I come now to the indicating mechanism, which consists of the multiplying lever F,
the flexible marking arm G, and the connecting rod H which connects the multiplying
lever to the diaphragm spring.
The multiplying lever I prefer to form at its rear end with a rectangular skeleton
frame which is hung by its sides upon pivots c. The connecting rod H, is solidly
fastened to the diaphragm spring below, and above, it is jointed or pinned at d to the
multiplying lever. The front and rear cross bars e of the skeleton frame in which
the rear portion of the multiplying lever is secured, are of metal, and by bending
them slightly to the front or rear as the case may be, the point of attachment of the
connecting rod to the multiplying lever, can be moved nearer to or further from the
axis of motion of the lever, thus adjusting with the greatest nicety the throw of
the lever, for a given vertical movement of the connecting rod.
The multiplying lever at its front extends through a passage or opening made for
it in the front of the frame B, and to its outer end is secured the flexible vertical
marking arm G. This arm may be formed and secured to the lever in a variety of
ways. The construction I now prefer on the whole is represented in the drawing.
As there shown, the marking arm which is composed of a flexible spring metallic
strip, provided at its lower end with a socket or holder g for the pencil or other
marking device, is secured at its upper end by a set screw or otherwise to a head gl
which is pinned or pivotted at g to the multiplying lever. A spring g³ bears out-
wardly against the upper portion of the head at a point above the pivot g² with the
effect of keeping the lower end of the flexible marking arm in contact with the paper,
as the said arm rises and falls with the multiplying lever.
The spring g is on or forms part of a second head g which is also pinned to the
multiplying lever on the pivot or axis g', and is prolonged into a spring arm G¹ which
extends down upon the rear face of the front of frame B, and presses against that
face--being provided at its contacting point with a roller g to reduce friction. This
arm serves in a measure to guide and steady the marking arm in its movement, the
two arms G G' forming in effect spring jaws which press against the front of the
frame B from opposite sides. This indicating mechanism is one in which the parts
are reduced to a minimum number, and in which this gain in simplicity is attained
without impairing the efficiency of the mechanism; indeed its efficiency is rather
enhanced than otherwise, owing, among other things, to the few connections and
consequent reduction of lost motion. I may remark here that while I have represented
this indicating mechanism as connected to and used in conjunction with a corrugated
convex diaphragm, yet the same may be used with diaphragms of other constructions--
whether corrugated or plain.
The electrical alarm which sounds whenever certain limits of pressure are exceeded

page_text: in either direction consists of an alarm bell I an automatic rheotome L for sounding
the hell a normally open electric circuit for the, same and two circuit closers N Ni
one for "high" and the other for "low" pressure by the operation of either one of
which the circuit can be closed. I am of course aware that an electrical alarm
included in a normally open circuit which is closed by suitable mechanism whenever
temperature or pressure or the like exceeds a certain limit in, either direction is not
new broadly considered. My improvements in this direction are designed to meet the
practical needs and requirements of the recording instruments to which my invention
relates and particularly to render the alarm susceptible of ready adjustment to any
given limits of pressure while permitting it at all times to be easily and quickly
tested to ascertain whether it is in proper condition without in any way disturbing or
affecting the particular adjustment to which it has been set.
Upon a suitable post on the frame of the instrument is fastened a bell I the
clapper I of which is fast to the armature lever i¹ of the magnet i the parts i¹ with
their circuit connections constituting the ordinary automatic rheotome of an alarm or
call bell. The "high" circuit closer consists of an insulated arm or rod N which has
a reciprocating motion imparted to it by being jointed to a projection n² extending
downwardly from one side of the skeleton frame of the multiplying lever. The
compound rod thence extends forward and out through a bearing (lined with insulating
material) in the front of the frame B. The "low" circuit closer consists of a similar
arm N similarly arranged and mounted on the opposite side of the skeleton frame
of the multiplying lever save that it is pinned or jointed to a projection n³ which
extends upwardly from said frame. Thus when the multiplying lover vibrates the
two rods will reciprocate in opposite directions--rod N advancing and rod N¹ receding
when the lever rises and moving in the contrary direction respectively when the
lever descends. In the path of each circuit closer, and in position to make contact
with it when it has advanced to the requisite extent is a stationary contact n or n².
Each contact consisting of an adjusting screw which screws through an opening
formed for it in the lower end of a spring arm o which hangs down in front of the
front plate of the instrument.
The upper end of the spring arm is curved or arched and at its extremity is
fastened by an insulated support to the frame B. By screwing the contacts n n¹ in
or out they can be adjusted so as to be met by their respective rods whenever the
lever rises or falls beyond a predetermined limit; at the same time the spring arms o
afford ready means by which each contact can be operated like a spring push button to
close the circuit whenever it is desired to test the condition of the circuit or the parts
included therein-the contact as soon as pressure is removed from it springing back
at once into its normal adjusted position.
In the main figure in the drawing both high and low alarms are to be sounded on
one bell located on the instrument itself and under this arrangement the wiring is as
follows, see Figure 5: from one pole of battery by wire 1 to frame of instrument from
frame of instrument to armature lever i¹ by wire 2 from backstop of rheotome by wires 3
to both contacts n n' from either circuit closer N or N¹ by wire 4 electrically connected to
both of said circuit closers to and through magnet i, and thence back to other pole of
battery. It may be desired at times to have two alarms-one on the instrument
itself and another located at a distant point and such an arrangement is represented
diagrammatically in Figure 6. The wiring and circuit arrangement in the instrument
is represented by the dotted lines and requires no explanation. In Figure 7 I have
shown diagrammatically still another arrangement-one in which the bell is removed,
from the instrument and in lieu thereof there are provided two bells-one for "high"
and the other for "low" pressure-placed outside of the gauge or at a distant point.
The wiring and circuit connections in this arrangement also are simple and require no
explanation other than that afforded by the figure itself.
"
Having described these improvements and the best way now known to me of
carrying the same into effect I desire to state in conclusion that I do not restrict
myself to the particular details herein before shown and set forth in illustrations of

page_text: these improvements for manifestly the same can be varied considerably without
departure from my invention; but what I claim as new and desire to secure by
Letters Patent is :
1. The combination of the diaphragm spring the multiplying lever the connection
between the lever and the diaphragm spring and the flexible marking arm attached
to and carried solely by the lever and hearing towards and against the surface to be
marked with yielding pressure substantially as and for the purposes herein before set
forth.
2. The combination of the multiplying lever the flexible marking arm attached
to and carried by said lever the diaphragm spring the connecting rod between the
diaphragm spring and the multiplying lever and the filling or backing for resisting
deflection of the diaphragm spring beyond a predetermined limit substantially as and
for the purposes hereinbefore set forth.
3. The combination of the diaphragm spring containing chamber the convexly
corrugated diaphragm spring located therein in such manner that the pressure will
be exerted against its convexed surface the multiplying lever the connection between
the lever and the diaphragm spring and the flexible marking arm attached to and
carried solely by the lever and bearing towards and against the surface to be
marked with yielding pressure substantially as and for the purposes herein before set
forth.
4. The combination with the corrugated diaphragm spring or springs and the
supporting base of the metal filling or backing moulded or shaped to the exact counter-
part of the shape assumed by the upper surface of the diaphragm when the latter is
distended or deflected to the predetermined limit and so located that the diaphragm
when thus distended or deflected will meet it throughout its entire surface and thereby
will be supported throughout its whole area against excessive pressure as and for the
purposes herein before set forth.
5. The combination in a pressure gauge with the diaphragm spring or springs
and the fluid chamber or receptacle of an untempered steel or iron diaphragm
bunched with said diaphragm springs substantially as and for the purposes herein-
before set forth.
6. The combination of the fluid chamber or receptacle the diaphragm spring or
springs the untempered steel or iron diaphragm bunched with said diaphragın springs
and the thin flexible sheathing for preventing corroding action upon the same
substantially as and for the purposes herein before set forth.
7. The combination with the indicating and recording mechanism and the alarm
bell and electrical appliances for operating the same of a circuit closer included in
the circuit of said electrical appliances and consisting of a rod connected to and
actuated from the indicating mechanism a stationary contact to and from which
said rod moves and a spring support in which said contact is adjustably mounted
substantially as and for the purpose hereinbefore set forth.
8. The combination with the indicating and recording mechanism and the alarm
bell and electrical appliances for operating the saine of "high" and "low" circuit
closers included in the circuit of said electrical appliances and consisting of rods
actuated from the indicating mechanisu to move to and from stationary contacts
said contacts having contact pins or points carried by and adjustable in spring
supports substantially as and for the purposes herein before set forth.
9. The combination of the diaphragm spring or springs the multiplying lever the
connecting rod between the lever and diaphragm spring the flexible marking arm
attached to and carried by the multiplying lever the reciprocating circuit closing
rod N or N jointed to and moved by the multiplying lever and the adjustable contact
point or pin n or n¹ and the flexible or spring support for the same substantially as
and for the purposes herein before set forth.
10. The multiplying lever secured at its rear to the cross bars of a rectangular
skeleton frame the sides of which are journaled in or pivoted to the frame of the
instrument in combination with the diaphragm spring or springs and the connection

page_text: between the same and the lever substantially as and for the purposes hereinbefore set
forth.
11. The combination with the pivoted multiplying lever of the flexible marking
arm and its fellow arm pivoted or pinned to the lever and extending down upon
opposite sides or faces of the front. plate of the instrument, and a spring whereby
said arms are caused to bear from opposite sides upon said plate with a constant
pressure throughout and during the movements of the multiplying lever substantially
as and for the purposes hereinbefore set forth.
Dated this 9th day of December 1890.
J. H. JOHNSON & Co.,
Agents.