IMPROVEMENTS IN ELECTRIC DEVICES FOR INDICATING SPEED AND FOR OPERATING SAFETY VALVES
Year: 1883

page_text: LETTERS PATENT to Robert Percy Sellon of Surbiton in the County of
Surrey, Electrical Engineer for an Invention of "IMPROVEMENTS IN ELECTRIC
DEVICES FOR INDICATING SPEED AND FOR OPERATING SAFETY VALVES
"
PROVISIONAL SPECIFICATION left by the said Robert Percy Sellon at the
Office of the Commissioners of Patents on the 31st May 1883.
ROBERT PERCY SELLON of Surbiton in the County of Surrey Electrical
Engineer "IMPROVEMENTS IN ELECTRIC DEVICES FOR INDICATING SPEED AND
FOR OPERATING SAFETY VALVES
"
My Invention relates to means and devices for obtaining indications of speeds of
motors such as steam or gas Engines Dynamos or other sources of power or for
indicating reversals of or variation in the speed of such motors by electricity thus
enabling one or more recording indicators to be placed at any distance from the
source of power all such appliances shewing the speed of or any variation in the
speed of such motors in any desired locality however far removed from the said
source of power or from each other.
My Invention further relates to automatic Electric safety valves forming either
a distinct apparatus independent of the ordinary safety valve applied to Engines
or other motors or an attachment actuating the said ordinary safety valve in case
this should not come into action when the pressure at which it may be set to open
is obtained.
In order to carry out the first part of my Invention I may employ the following
means: Any suitable centrifugal arrangement such as for instance an ordinary
steam Engine Governor is actuated by means of a belt or gearing or in any
convenient manner from the motor of which it is required to obtain indications of
speed, the said centrifugal arrangement may be made to vary the thrust of an
arın or similar arrangement which by means of a roller contact or otherwise may
be made to insert more or less resistance into one of the arms of "bridge" or
balance or vary the proportion between two of the arms of a "bridge" and so by

page_text: inserting a greater resistance on one side of the "bridge" than on the other
causing the balance to be disturbed and a corresponding current to flow through
the coils of an indicator which produces a deflection on a needle or pointer and
thus indicates the speed of the motor or dynamo-I may cause the said Indicator
to take the place of the Galvanometer generally used in connection with the
"bridge" or "balance the dial or face of such indicator being graduated or
marked out in such a manner as to shew the number of revolutions of the motor
or dynamo or in any suitable or convenient manner. The above indicator may
be placed at any distance from the Apparatus actuated by the Engine or other
motor being connected thereto merely by two wires leading from the above
apparatus. It is obvious that any number of these indicators may be placed on
the same circuit with the above apparatus all shewing alike the speed of the
Engine or Dynamo or other motor and they may be placed at any desired distance
from one another. In order to prevent a current from the batteries or other means
of obtaining electrical energy from traversing the coils of the "bridge" or indicator
when the Engine or dynamo has ceased to revolve, I may cause the battery circuit
to be made and broken by the advance or retreat of the arm actuated by the
centrifugal Governor so that the circuit shall only be established when the Engine
or dynamo commences to revolve
Or instead of the above arrangement I may employ a dynamo or preferably a
Magneto Electric Machine or any suitable device driven from the motor or dynamo
of which it is required to obtain indications of speed or variation in speed by any
suitable means such as a belt er gearing such dynamo or Magneto Electric
Machine transmitting current to a second dynamo or Electric motor which may
be placed at any distance from the first Dynamo and in any desired locality being
merely connected thereto by two wires. This motor may actuate any suitable
centrifugal arrangement or governor as before mentioned which will in turn vary
the thrust of an arm which may by means of a train of wheels or in other suitable
manner impart motion to a needle or pointer such needle indicating on a dial the
variations of speed of the Engine dynamo or other motor_
In carrying out the second part of my said Invention I may cause the Indicator
needle of a Bourdon or other pressure Guage to complete a battery or electrical
circuit by coming into contact during its movement round the dial or face of the
pressure guage with a metal or suitable stop attached to the frame of the pressure
guage if desirable; the Indicator needle and the stop being insulated from one
another Included in the circuit of the battery or other Electrical circuit may be
placed a solenoid, magnet, or magnets, which when the circuit is completed by the
indicator needle coming into contact with the above mentioned stop may by the
attraction of a core or keeper be made to open the valve and permit of the escape
of steam in any convenient manner such for in-tance as by releasing a weight
where a comparatively small magnet will do the work of releasing the above
weight, the greater work of opening the valve being done by the gravity of the
weight
Or I may sometimes carry this part of my Invention into effect in the following
manner a circuit being closed as above mentioned by the indicator needle
coming into contact with a stop upon the pressure guage such stop being
adjustable so that the circuit may be completed at any desired pressure the
adjustment being preferably such that the following Electrical device will come
into play only when the valve fails to act, a current will traverse the coils of a
solenoid magnet or magnets which by the attraction of a core or keeper inay be
made to release a spring or weight in such a manner that an impulse shall be
imparted to the valve spindle causing the valve to open and permitting of the
escape of steam:-On the pressure falling the valve may close in the ordinary
way the above device being set to come into operation again at the desired
pressure.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Robert Percy Sellon in the Great Seal Patent Office on the
30th November 1883.
ROBERT PERCY SELLON of Surbiton in the County of Surrey Electrical
Engineer "IMPROVEMENTS IN ELECTRIC DEVICES FOR INDICATING SPEED AND
FOR OPERATING SAFETY VALVES
"
My Invention relates firstly to means and devices for obtaining indications of.
speeds of motors such as steam or gas Engines dynamo electric machines or other
machinery for obtaining motive power or for indicating variations in the speed of
such motors or machinery by electricity thus enabling an indicator or indicators
to be placed at any distance from the source of power or the indicators to
be placed at any distance from each other all such appliances shewing in any
desired locality the speed of or the variations in the speed of such motors or
machinery however far removed from the said source of power or from each other
the indicators may be.
My Invention further relates to automatic electric safety valves as hereinafter
described the said valves constituting either a distinct apparatus independent of
the ordinary safety valve applied to the boilers of engines or other motors or
apparatus or constituting an attachment for actuating the ordinary safety valve to
prevent as far as possible risk of its not coming into action when the pressure at
which it may be set to open is attained
"
"
In order to carry the first part of my Invention into effect I employ any suitable.
centrifugal arrangement such for example as the balls of an ordinary steam engine
governor actuated by means of a belt or gearing or in any convenient manner
from the motor or machinery the speed of which is to be indicated-The said
centrifugal arrangement is made to vary the thrust of an arui connected preferably.
to the spindle of the centrifugal arrangement this arm by the motion imparted to.
it by the centrifugal arrangement disturbing the equilibrium of an electrical.
"bridge
or balance-At any desired distance from this apparatus may be placed
an indicator consisting of a magnet or solenoid or magnets or solenoids and an
indicating needle or pointer to which motion is imparted by an armature or core
being attracted by the said magnet or solenoid or magnets or solenoids―This
indicating apparatus takes the place of the galvanometer generally used in
connection with a "bridge or balance the needle or pointer indicating upon a dial
graduated to denote speed tlie extent to which the equilibrium of the "bridge
or balance has been disturbed and consequently the number of revolutions of the
machine-The said indicator may be placed at any distance from the "bridge" or
balance being connected electrically thereto by means of conductors leading from
the said bridge or balance-In order to prevent a current from the batteries or
generators of electricity used in connection with the bridge from traversing the
arms of the bridge while the apparatus is at rent or when the engine or machine
whose speed is to be indicated has ceased to revolve or before it has attained a
speed requiring to be indicated I may cause the electrical circuit of the said
bridge" or balance to be made and broken by the advance or retreat of the arm
actuated by the centrifugal arrangement so that the circuit shall only be established
when the said engine or machine commences to revolve
46
"
Figure of the accompanying drawings illustrates diagrammatically a system
mode or manner in or under which the said first part of my Invention may be
carried into practical effect A represents any suitable centrifugal device which

page_text: when the balls thereof open out exerts a thrust upon the arm a which causes a
second arm a³ to which it is connected or upon which it bears to revolve about a
centre a³ the metal roller a' at the end of the arm a making contact with the
platinum wire b (or other suitable metallic wire or conductor) The said platinum
wire b on either side of the roller a' constitutes part of two arms of the "bridge"
or balance the fixed resistances b b constituting the other two arms-The circuit
through c cand a' may be closed (as soon as motion is imparted by the centrifugal
arrangement to the arm a) by the arm a closing the circuit between the contact
surface and the roller a so as to prevent the necessity for maintaining the
electric current when the machine is not in operation or until it has attained the
speed at which indication is necessary. D represents the battery or generator of
the electric current employed From the above described device two wires ff are
led to the indicating device F and connected to the solenoid f' which takes the
place of the galvanometer of the ordinary "bridge" On the equilibrium of the
bridge" being disturbed by the movement of the arm a³ a current passes
through the said solenoid and attracts a core f³ which is provided with a rack f
acting on a pinion g on the axis of the pointer g³ thus causing the said pointer to
indicate the speed of the Engine or machine upon the dial H
26
It is obvious that any number of indicators F may be placed on the same
circuit with the above apparatus all shewing alike the speed of the Engine or
machine and they may be placed at any desired distance from one another The
solenoid may it is evident be replaced by an ordinary electro magnet if desired
the armature thereof being arranged to operate upon the needle or indicator
through any suitable mechanism
Instead of the above described arrangement I may employ an electro dynamic
machine driven by a current derived from the machine whose speed is to be
indicated This current in the case where the speed of a dynamo electric machine
is to be indicated may be taken direct from the said machine but where the
machine whose speed is to be indicated is not a generator of electricity a. small
dynamo electric machine may be driven therefrom to supply the current to
the said electro dynamic machine-The indicating apparatus (of which the said
electro dynamo machine forms parts) is connected to the generating dynamo by
means of suitable conductors so that the said indicating apparatus may be at any
may construct
required distance from the machine whose speed is to be indicated
the said indicating apparatus as follows and as shewn in the diagram Figure 2.
In the case of a machine which is not a generator of electricity the dynamo
electric machine J is caused to rotate by a strap or other device from the machine
whose speed is to be indicated-In the case where the machine whose speed is to
be indicated is a generator of electricity the current is conveyed therefrom as
The
indicated by the dotted lines without the intervention of the machine J
electro dynamic machine K is caused to rotate by means of the current so
supplied
In the said Figure 2 the machine (shewn at L) the speed of which is to be
indicated is supposed to be a machine which is not a generator of electricity
In connection with the spindle of this motor K is a centrifugal device which
varies the thrust of an arm which by means of suitable gearing causes a needle or
pointer to revolve around a dial graduated to denote speeds
same as the indicating
This arrangement is or may be substantially the
arrangement F Figure 1 except that the part which actuates the finger or pointer
is acted upon directly by the centrifugal arrangement-The action of this apparatus
is as follows When the generating dynamo (either the dynamo whose speed is to
be indicated or the small dynamo J as the case may be) is set in motion a current
which varies in intensity according to the speed of the said Dynamo is passed
through the receiving Moter K causing it to revolve at a speed varying according
to the current passing through it. These variations in speed affect the thrust of
the arm the thrust being in accordance with the speed of revolution of the

page_text: centrifugal arrangement and consequently with that of the machine whose speed
is to be indicated so that in this way the pointer is caused to indicate upon the
dial the revolutions of the said machine of which it is required to indicate the
speed. It will be evident that more than one electro dynamic machine and
indicating arrangement inay be employed if desired so that the speed may be
indicated at more than one place.
In carrying out the second part of my said Invention I may cause the Indicator
needle or equivalent part of a Bourdon or other pressure gauge or device acted upon
by the pressure in the boiler or other vessel to complete a battery or electrical
circuit by coming into contact during its movement or during its travel round the
dial or face of the pressure gauge with a metal or conducting stop attached to the
frame or other suitable part of the pressure gauge or equivalent device. Included
in the circuit of the battery or other electrical circuit is a solenoid magnet or
magnets which when the circuit is completed by the indicator needle coming into
contact with the above mentioned stop may by the attraction of a core or armature
be made either directly or through any suitable machanism to open the valve and
permit of the escape of steam. This opening of the valve may be effected by
releasing a weight when a comparatively small magnet will be sufficient to cause
the releasing of the said weight the greater work of opening the valve being done
by the gravity of the weight or any other device suited to the purpose may be
employed.
Or I may carry this part of my Invention into effect in the following manner
A circuit is closed as herein before described by the indicator needle coming into
contact with a stop upon the pressure gauge or equivalent device. The said stop is
adjustable so that the circuit may be completed at any desired pressure the adjust-
ment being preferably such that the following electrical device will come into play
only when the valve fails to act When this is the case a current will traverse tho
coils of a solenoid magnet or magnets which by the attraction of a core or keeper is
made to release a spring or weight in such a manner that an impulse is imparted to
the valve spindle causing the valve to open and permitting of the escape of steam
or the relief of pressure On the pressure falling the valve may close in the
ordinary way the above device coming into operation again at the desired pressure.
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the saine is or may be used or carried into
effect I would observe in conclusion that what I consider 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-In electric devices for indicating speeds or variations of speeds the
combination of a centrifugal arrangement or governor and a "bridge" or balance
for giving the required indications at any suitable place or places substantially as
herein before described.
Second The arrangement and combination of parts constituting the speed
indicator herein before described and illustrated by Figure 1 of the accompanying
Drawings.
Third-In electric devices for indicating the speeds of steam engines or
machinery the combination of an electricity generator and electric motor or motors
and a centrifugal arrangement or governor or governors acting upon an indicator or
indicators substantially as hereinbefore described and illustrated by Figure 2 of the
accompanying drawings.
Fourth In electric devices for indicating the speeds of electricity generators or
dynamo electric machines the combination of an electric motor or motors and a
centrifugual arrangement or governor or governors acting upon an indicator or
indicators substantially as herein before described and illustrated by Figure 2 of the
accompanying Drawings,
Fifth In electric devices for operating safety valves the employment of an
electro magnet or solenoid energized by an electric current the circuit of which is
•

page_text: completed by a pressure gauge or equivalent device acted upon by the pressure of
the boiler or other vessel or container substantially as herein before described.
In witness whereof I the said Robert Percy Sellon have to this my Specification
set my hand and seal this twenty eighth day of November One thousand eight
bundred and eighty three
ROBERT PERCY SELLON (L.S.)