IMPROVEMENTS IN PRESSURE AND FLUID LEVEL INDICATORS
Year: 1858

page_text: LETTERS PATENT to Edouard Aristide Servier, of Paris, in the Empire
of France, Engineer, for the invention of "IMPROVEMENTS IN PRESSURE
AND FLUID LEVEL INDICATORS,"
Sealed the 11th February 1859, and dated the 4th December 1858.
PROVISIONAL SPECIFICATION left by the said Edouard Aristide Servier
at the Office of the Commissioners of Patents, with his Petition, on the
4th December 1858.
I, EDOUARD ARISTIDE SERVIER, of Paris, in the Empire of France, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
PRESSURE AND FLUID LEVEL INDICATORS," to be as follows:-
This Invention consists in the application and use for the purpose of
indicating a maximum and minimum pressure of steam fluids, air, or gases, or
for indicating a maximum or minimam level of any liquid of electric currents,
and suitable apparatus for making and breaking contact, and reversing such
currents,in combination with ocular or auricular indicating mechanism, so that
two different signals may be conveyed to any required distance along one wire
or circuit, which signals will at once indicate that the pressure or level of the
fluid or vapour experimented upon has attained a given maximum or minimum,
each limit being indicated by a different signal. According to one form of my
apparatus, which, however,may be modified invariousways, without interfering
with the principle of my Invention, I propose to attach insulated metallic
Price 8d1

page_text: contact pieces to the stem or spindle of the float or other indicating apparatus,
and in juxtaposition to these contact pieces are other stationary or adjustable
contact pieces, connected respectively by wires with a battery and with a
galvanometer and magnetised needle, or with an electro-magnet and needle,
so that as the spindle of the indicator rises or falls to a maximum or minimum
elevation, the circuit will be established, and a current produced in one
direction or the other, according to the contacts made, which currents will act
upon a needle, and deflect it in opposite directions, so as to indicate respec-
tively a maximum or minimum elevation of the indicator spindle. Two electric
bells, each giving a different sound, may be placed in circuit with the needle,
so that simultaneously with a deflection in either direction a certains ound
will be produced by the striking of one or other of the bells. By suitably
adjusting the distances between the contact surfaces, the mean between the
maximum or minimum elevation of the indicating spindle can be regulated to
the greatest nicety. It will be observed that the movement in this apparatus
or commutator is simply a rising or falling one in a vertical line, but the
apparatus can be readily made to change the direction of the currents by a
rotatory reciprocatingmovement, in which case a pair of vibrating needles are
employed fixed on to a horizontal spindle, and insulated from each other, such
needles making and breaking contact, and reversing the currents, by coming
in contact with certain stud pins, suitably disposed, either permanently or inan
adjustablemanner, on two sets of concentricsemicircularconductorscomposedof
any good conducting metal, and disposed so as to forma divided circleconcentric
with the axis of the needles. These segments are respectively connected with
a battery, and with the galvanometer and magnetised needle, or with the
electro-magnet and needle. and alarm bells herein-before described, for
indicating the maximum or minimum pressure or level of the vapour, gas, or
fluid experimented upon. In both arrangements of apparatus no signal will
be given or indication made, so long as the pressure or level remains between
the two given points of maximum and minimum, as no circuit will be estab-
An
lished until such extremes of pressure or level have been attained.
automatic electric indicator, constructed on the principles herein-before set
forth, will be found particularly applicable to gas or water mains or pipes for
the purpose of indicating the maximum or minimum pressure on any parti-
cular portions of such mains or pipes, and also to the reservoirs of waterworks,
to indicate the approximate level of the water contained therein, and indeed in
all cases where indications of a maximum or minimum pressure or level are to
be transmitted through great distances.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edouard Auguste Servier in the Great Seal Patent Office on
the 19th March 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDOUARD
ARISTIDE SERVIER, of Paris, in the Empire of France, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of December, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give and grant unito
me, the said Edouard Aristide Servier, Her special liceuse that I, the said
Edouard Aristide Servier, my executors, administrators, and assigns, or such
others as I, the said Edouard Aristide Servier, my executors, administrators,
cr assigns, should at any time. agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,"
should and lawfully night make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of
IN PRESSURE AND FLUID LEVEL
Man, an Invention for "IMPROVEMENTS
INDICATORS," upon the condition (amongst others) that I, the said Edouard
Aristide Servier, by an instrument in writing under my hand and seal, should
particularlydescribe and ascertain the nature of the said Invention, and in what
manuer the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar mouths next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edouard Aristide Servier, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say:-
My said Invention relates to certain peculiar constructions, arrangements,
and combinations of apparatus for the purpose of indicating a maximum or
minimum pressure of steam, air, or gas, or for indicating a maximum or
minimum height or level of the surface of any liquid in a vessel or reservoir.
This apparatus, which I shall now proceed to describe, and which constitutes
the essential feature of my present Invention, is applicable to all pressure aud
fluid level indicators, whether indicating by a vertical motion in a straight line
or by a circular motion round a dial, and its object is to indicate at any
distance from the locality where the indicator is placed the moment at which

page_text: the pressure or level, as the case may be, has reached a maximum or minimum,
the limits being adjusted or regulated beforehand to suit the requirements of
the case.
The peculiar characteristic of my apparatus is the giving of a different
signal for each extreme limit, and of a third signal for the intermediate
degrees, of pressure or points of elevation. My Invention is based upon the
following well-known principle:-Where an electric current passes along a
wire in the immediate neighbourhood of a magnetic needle, the latter will be
deflected from its normal position in one direction or the other according to
the direction of the electric current. I have applied this principle to
existing pressure and level indicators for obtaining the objects herein-before
mentioned.
In carrying out my Invention, I adapt to the pressure or level indicator or
commutator, arranged in such a manner that when the indicator assumes the
position corresponding to a maximum or minimum limit, which limit is
required to be signalled or indicated at some distance removed from the
indicator, an electric circuit is established, but in such a manner that when
the maximum limit is to be signalled the current passes in one direction,
whilst for a minimum limit the current passes in the contrary direction along
the same wire which connects the two stations or localities. If a galvano-
meter, having either a horizontal or a vertical needle, be placed within
and form part of the circuit at the distant station, the magnetic needle of the
galvanometer will be deflected in one direction for a maximum, and in an
opposite direction for a minimum limit of pressure or level, and will remain in
its normal position during all intermediate points between these limits. In
lieu of a galvanometer, an electro-magnet may be placed in circuit, the poles
of which will be reversed by simply reversing the currents by the aid of a
commutator. By this means one of the poles of a magnetic r.eedle placed
near the electro-magnet will be attracted by one end of the magnet for the
maximun, limit, and by the opposite end for the minimum limit, the normal
or intermediate position being always maintained during the intermediate
positions of the indicator.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, & for that purpose I shall
refer to the several Figures on the Sheets of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts throughout all the
corresponding Figures.
Figure 1 on Sheet 1 of the accompanying Sheets of illustrative Drawings
represents the application of my vertical commutator for definite and fixed

page_text: limits to an indicator acting vertically or in a straight line. O, O'. represents
the spindle of the indicator, on to which I fix a short rod or spindle composed
of ivory or other good non-conductor. This rod carries two metal contact
pieces A, B, which are thus effectually insulated. The other portion of the
commutator, which is' fixed and quite independant of the spindle O of the
indicator, consists of four metal contact pieces a, b, c, d, e, f, g, h, i, j, k, l, and
m, n, o, p, insulated one from the other by being fixed on to any good non-
conductor of electricity. The parts a, b, and i, j, are in the same horizontal
plane, as are also the parts c, d, and m, n, f, e, and p, o, g, h, and l, k. The
vertical distances or spaces a, d, and e, h, which are alike, represent the space
through which the indicator spindle moves to indicate a predetermined
maximum or minimum pressure or level. The points a, d, e, h, are in one
vertical line, as are also the points i, m, p, l. The part a, b, c, d, is in com-
munication, by means of a wire, with one of the poles of a battery, and the
part e, f, g, h, with the opposite pole of the battery. The part i, j, k, l, is
connected with one end of a wire leading to a galvanometer, or to an electro-
magnet; and, lastly, the part m, n, o, p; is connected with the other end of the
wire last referred to.
When
I shall now proceed to describe the operation of this apparatus.
the pressure or level reaches the minimum limit, the indicator spindle
descends and brings the metal contact piece A in metallic contact with
the parts h and, and the piece B in contact with the parts & and m, the
circuit is thus established, and the electric current passes along the wires
in the direction indicated by the red arrows, and the magnetic needle of
the galvanometer (Figure 2) assumes the position iudicated in red lines.
When, on the contrary, the pressure or level reaches its maximum limit, the
indicator spindle O rises, bringing the piece A in contact with the parts e and
p, and the piece B in contact with and i. The circuit is again established,
but the electric current pursues au opposite course indicated by the blue
arrows, and the magnetic needle is also deflected in the opposite direction, as
shewn by the blue lines. When the pressure or level is maintained between
these two limits, the metal pieces A, B, on the spindle of the indicator being
out of contact with the metallic contact pieces of the commutator, the circuit
will be broken, and the magnetic needle will rest in its vertical or normal
position. Should an electro-magnet be substituted for the galvanometer, the
current tor the minimum limit. passing in one direction will cause the pole A of
the electro-maguet (Figure 2) to become north; the needle which is placed
above withits south pole downwards will have its lower end attracted and will
assume the position indicated in red lines; but when the current passes in

page_text: the contrary direction (as in the case of the maximum limit for example), the
pole B will become north, and the needle will be attracted to the opposite side,
as shewn by the blue lines. In some cases it will be desirable to be enabled
to vary at will the extreme limits of maximum and minimum pressure or
level, for which purpose I propose to use a commutator of variable limits,
constructed in the following manner :-The parts a, b, and i, j. f, e, and p, o,
of the preceding commutator, which I call the "vertical commutator," with
fixed limits, are moveable, and detached from the metal pieces of which they
form part, and upon which they are capable of sliding with some amount of
friction; they are fixed into an insulated plate, which is capable of vertical
adjustment either up or down, by means of an adjusting screw. By this means
the relative positions of the contact points of the commutator may be varied,
thus limiting the travel of the indicator spindle, and regulating or adjusting
the difference between the maximum and minimum. In order to vary the
absolute value of these limits it is simply necessary to raise or lower the ivory
rod which carries the two metal pieces A and B, and is fitted for this purpose
on to the spindle of the indicator by means of a set screw, as shewn in the
detail edge view of the rod at Figure 1.
The above description of my vertical commutator will enable the working
of the apparatus to be clearly understood, but in practice it may be still
further greatly simplified by adopting the following modifications:-
The metallic contacts a, b, c, d, e. f, g, h, are dispensed with and the poles
of the battery are made to communicate directly by means of flexible wires
which will not interfere with the motions of the indicator rod or spindle with
the metal pieces A and B, fitted to the indicator rod. The effect of the
commutator is then the same as before, whilst its construction is less complex.
My commutator is also applicable to circular indicators, that is, to those
indicators which are read off from a dial face or are of a circle, the vertical
movement being transformed into a circular motion so as to turn an indicating
needle or pointer. The form alone of this apparatus is varied, its effect being
precisely similar to that previously described, namely the reversal of the
electric current by the indicator itself. I have represented a side elevation
plan and edge view of this commutator (which I call the circular commutator]
at Figures 3, 1, and 5 respectively on Sheet 1 of my Drawings. O is the
axis of the indicating needle P, the extremities of which travel over a circle
composed of four metal segments or arcs A B, CD, E F, and G H, which
areinsulated from each other.; upon each of these segments are fitted (eithe
immoveably or in such a manner as to be capable of adjustment thereon a
will, according as the commutator is intended for fixed limits or for variabl

page_text: The
limits), two metal pins a b, vd, cj, gh, forming contact pieces.
segment or arc A, B, is in communication with one of the poles of a battery Q,
the segment or arc E, F, is in communication with the opposite pole of the
same battery; the segment or arc C, D, is connected with one end of a wire w
leading to the galvanometer or electro-maguet; and the segmentor arc G, H,
is connected with the opposite end w¹ of the same wire. The needle of the
indicator is composed of two identical pieces of metal P. P1, (Figure 5) placed
the one behind the other, and insulated from each other, as shewn by the part
colored red in that Figure. These twin needles carry at each of their extre-
mities a flexible steel spring m, n, o, p, establishing the electric circuit
by coming in contact with the metal pins herein-before referred to in the
segment or arcs. The pins e, a, d, h, are in the same radius line, and the pins
g, c, b, f, are in another radius line, as will be seen on referring to Figure 3.
The two metal blades which constitute the twin needle of the indicator turn
simultaneously, the two being connected together; but one piece moves in
front of the segments, and the other moves behind them (see Figure 5), whilst
the pins e, g, f, d, project from the front of the segments, and the pius u, c, b,
, project from the back of the segments, so that each needle may come in
contact only with the proper pins. By this means, when the twin needles of
the indicator assume the position shewn in red lines and corresponding, for
example, with the minimum limit the electric circuit will be established and
the current departing from the positive pole of the battery, will pass along the
segment E, F, and the pin e, the front needle P', the pin d, and the segment
C, D, and follow in the direction of the red arrows, the wires which connect
the two stations; the current will then return to the negative pole of the
battery by the segment G, H, the pin h, the back needle P, the pin a, and
the segment A, B. When the needle is in the position shewn by blue lines
and corresponding, for example, to the maximum limit, the circuit will beagain
established, but in such a manner as to reverse the direction of the current
which, in this latter case, will follow the segment E, F, the pin f, the front
needle ", the pin g, the segment G, H, and pass along the wire w¹ in the
manner shewn by the blue arrows, back again to the negative pole by the
segment C, D, the pin c, the back needle P, the pin b, and segment A, B.
I thus obtain the same results from indicators moving in a rectilinear direction
and the same set of signals will be given by applying my system to either one
or the other of these two kinds of apparatus. By varying the extent of the
are described by the needle (by suitably displacing and adjusting the contact
pins), but in such a manner that they will remain in the same radii, the
distance between the maximum and minimum will be varied, and the absolute

page_text: value of these limits will be varied by turning more or less the insulator upon
which the metallic segments are fixed. The construction of this circular
commutator may, like the vertical commutator, be considerably simplified.
Figure 1 on Sheet 2 of my Drawings represents a front elevation of such
simplified modification; Figure 2 is a vertical section of the same taken
through the needle axis; and Figure 3 is a plan. In this latter arrangement
a direct metallic communication is established between the two poles of the
battery and the twin needles, but in such a manner as not to interfere with
their free movements. Two metallic arcs or segments A, B, and E, F, are
required fitted respectively with steel springs a, a', and d, dl, tipped with
platinum. The two needles K and L are both on the same side of the arcs
or segments, and are fixed upon the axis O in such manner as to be insulated
from each other. Z and are two springs which bear each upon the axis of
one of the needles, and are severally connected by wires with the two poles of
the battery; G, H, I, J, is a circle of non-conducting material for the purpose
of insulating the segments from the central supporting arms or disc, as is
clearly shewn in Figure 2. Supposing a maximum limit be attained, the
needles will be deflected so as to come in contact with the springs a' and a,
the current will then pass through the spring or wire Z, along the needle K,
spring d, segment E, F, and along the wire connected therewith in the
direction indicated by the blue arrow, returning to the battery by the segment
A, B, the spring a¹, needle L, and spring or wirez'. When a minimum limit
is attained, the needles will be brought into contact with the springs a and di
and the current will pass in the direction indicated by the red arrow, that is,
through the needle K, spring a, and segment A, B, and return by the
segment E, F, spring a needle L, and spring or wire Z. The springs a' and
d are carried respectively by the clips C and D, which are free to slide along
the periphery of their respective segments for the purpose of adjusting the
apparatus to different limits, each slide being fitted with a binding or set
screw for the purpose of fixing it in any desired position on its segment.
The system of signals may be perfected by the use of two electric indicating
bells giving a different sound for each of the extreme positions of the indicator.
I carrying out this idea, the axis of the magnetic needle (Figures 2, 6, and
7, Sheet 1) carries two platinum wires a, b, and a, b, bent into arcs of a
circle, as shewn. When the magnetic needle is deflected in one direction by
the passage of the current, one of the extremities a and a¹ of each of these
wires plunges into a small cup of mercury on the binding screws p,p. To
one of these screws p is screwed one of the ends of the coil wire arc of electro-
magnet, connected with the electric bell S (the other end of the wire being in

page_text: communication with one of the poles of a battery). To the other screw p' is
screwed a copper wire communicating with the other pole of the battery.
The circuit is therefore established, and the current passing through the axis
of the needle by means of the platinum wires, and through the electro-magnets
of the bells or sounding apparatus causes this latter apparatus to be put into
operation. The same disposition being symmetrically repeated, it follows that
when the magnetic needle is deflected in the contrary direction, the current
will pass through the electro-magnet of the second bell, which is consequently
sounded. The difference of tone of the two bells will thus serve to indicate to
which side the needle is deflected, and consequently whether the maximum or
minimum limit is attained by the indicator; the blue and red lines in Figure
2, Sheet 1, as well as in all the other Figures, indicate the relative positions
of the apparatus at the maximum and minimum limits. The action of the
electro-magnet upon the maguetic needle is so energetic even with a very
weak battery, when this needle is properly mounted upon pivots, that it will
not be found necessary to employ mercury to establish a perfect electric
contact. I therefore replace the two platinum wires with which the magnetic
needle is furnished, by two steel springs arranged in a similar manner, and
having the same form, and terminating at each extremity by a small blade of
platinum; these springs, by the play of the magnetic needle, come in contact
with other springs also terminated with platinum, and in communication with
the binding screws p, p', these latter springs replacing the mercury.
All
these springs are so disposed, having their extremities which come in contact
furnished with platinum, that no oxidation will be produced, which would be
apt to interfere with the perfect contact of the metals. The two electric bells
may be put into operation by the same battery, in place of having a separate
battery for each bell, for this purpose it will suffice to connect by a metal wire
two of the binding screws which contain the mercury, or the springs furnished
with platinum; those two, for example, with which the platinum wire a¹, b',
forms contact by the play of the needle in one direction or the other. One of
these binding screws is placed in communication with one of the poles of the
battery, whilst the other pole communicates at the same time with one of the
extremities of the electro-magnet of each 'bell. The apparatus works as
lierein-before described, one battery only being employed to act upon the
two bells.
In order to simplify the apparatus the two electric bells may be combined
into one apparatus, arranged in the following manner:-Two electro-magnets
E. E', (Figure 4, Sheet 2 of my Drawings) are placed face to face, and
between them is the contact piece c suspended by a steel blade spring, after

page_text: the manner of a clock pendulum. This contact piece carries at its lower
extremity, which is considerably reduced in thickness to render it flexible, the
hammer head M, which will strike either the small bell T or the larger bell
T, 80 as to produce a different sound, according to the direction of deflection
of the magnetic needle. The contact piece is in communication with one of
the poles of the battery P by means of the binding screw p. A spring r, r³,
is placed in each side of the contact piece c, and these springs are in metallic
contact therewith by the aid of the two projections s, s¹, on the contact piece.
The spring communicates with one of the extremities of the coil of the
electro-magnet E', and the spring with one of the extremities of the coil
of the electro-magnetic E; the other extremity of the wire coil communicates
with the other pole of the battery by the intervention of the well-known
arrangement applied to the magnetic needle, that is to say, that when the
magnetic needle is deflected one only of the electro-magnets will be found in
the electric circuit and become excited. Suppose the magnetic needle to be
deflected to the left, it enables the current to pass through the magnet E;
this current passes through the binding screw p, the contact piece c, the
spring, the electro-magnet E, and will regain the negative pole by the axis
of the needle; but the projection S₁ will leave the spring, and the current
will be interrupted, and the spring r will compel the contact piece c to resume
its vertical position. It will again come in contact with the spring r,and the
same effect will be produced, and the hammer M will strike with repeated
strokes upon the bell T. When, on the contrary, the magnetic needle is
deflected to the right, it will establish the circuit through the electro-magnet
E, and the hammer M will strike the bell T.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as variatious may be made therefrom without deviating
from the principles or main features of my said Invention; but what I con-
sider to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent, is,―
First, thegeneralconstructions, arrangements,and combinationsofindicating
apparatus, in the mauner and for the purpose herein-before described and
illustrated on my Drawings.
Second, the berein-before described peculiar constructions and arrange-
ments of commutators or apparatus for reversing electric currents when used
in the manner and for the purpose herein-before set forth.

page_text: Third, the combination of my improved commutator with any convenient
pressure or level indicator, for the purpose of indicating at a distance by
separate and distinct signals or signs the attainment of a given maximum or
minimum pressure or level, as herein-before described.
Fourth, the system or mode of indicating at any distance the attainment of
a maximum or minimum pressure or level, by using one electric wire or circuit
in combination with a magnetic needle or electro-magnet, each reversal of the
current in the wire producing a different signal, as herein-before described.
In witness whereof, I, the said Edouard Aristide Servier, have hereunto
set my hand and seal this Fourth day of March, One thousand eight
hundred and fifty-nine.
EDOUARD ARISTIDE SERVIER. (...)