Improvements in Steam Engine and like Indicators.
Year: 1898

page_text: Date of Application, 26th July, 1898-Accepted, 27th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in Steam Engine and like Indicators.
I, GEORGE FRANKLIN ATWOOD, of 20, Hurlbut Street, Orange, in the County of
Essex and State of New Jersey, United States of America, Electrical Engineer,
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:
My invention is designed to give continuous measurements by visual indications
of the mean or average pressure of energy given to prime movers, such as steam,
gas, air, and water motors, and in such manner that the indications will be of a
dead-beat" nature; that is to say, will give indications of varying loads put upon
the prime mover without sudden or violent fluctuations.
To this end my invention consists in a novel instrument for accomplishing this
result, and the especial points of novelty thereof will be particularly pointed out
in the claims at the end of the following specification, reference being had to the
accompanying drawings for a full understanding of the invention, in which,
Figure 1 is a vertical sectional view of the entire instrument taken on the
line yy, Figure 2.
Figure 2 is a rear elevational view of the instrument as seen looking at Figure 1
from the left toward the right hand side of the drawings, part of the casing being
broken away to better illustrate the interior structure of the instrument.
Figure 3 is a front elevational view, as seen looking at Figure 1 from the right
toward the left hand side of the drawings.
Figure 3 is a detail plan view; and,
Figure 3" is a side elevational view of an adjustable supplemental index to be
used in connection with the stationary scale of the instrument.
Figure 4 is a transverse sectional view of the instrument taken on the line y-y,
see Figure 1, and as seen looking at that figure of the drawings from the right
toward the left hand side thereof.
Figure 5 is a sectional view taken through Figure 6 on the line z-z, parts of
the instrument being shown in elevational view and as seen looking at said figure
from the bottom toward the top of the drawings in the direction of the arrows.
Figure 5 is a detail view of one of the nozzles which directs the propelling
medium, such as steam, upon the buckets or vanes of the motor.
Figure 6 is a front elevational view of the nozzles and the pivoted screens for
opening and closing the outlets of the nozzles and the interconnected mechanism
for effecting such result.
Figure 7 is a side elevational view of an ordinary steam engine illustrating the
application of my invention thereto, parts of the engine and instrument being
broken away to better illustrate the working of the same.
Prior to my invention it was customary in measuring the mean effective pressure
on the piston of a steam engine or analogous prime mover to utilize a "steani engine
indicator" the motive part of which was actuated by the steam as it entered the
card" during
cylinder at one end thereof and caused to trace a diagram upon a
"

page_text: one or two strokes of the engine or motive device. This diagram was then used as
the basis of a computation of the amount of energy given to the piston during the
particular interval occupied in its construction. The calculations were usually
made by tracing the diagram or card" by a planimeter, in order to obtain the
area thereof, and then by a well known formula the mean effective pressure and
total energy were calculated. Such diagram or card as it is termed, is always
traced upon a reduced scale and it is obvious therefore that any error in the
measurement of its area or average height which represents the mean pressure will
be multiplied in a ratio corresponding to the reduction of the scale upon which
the "card" is constructed. It is well known, furthermore, that these computations
involve considerable time and are, at best, only momentary indications of the actual
energy used. It is very desirable, therefore, to devise an instrument which will
at all times indicate upon visual inspection the actual energy given to the piston
without the necessity of performing laborious calculations, and it was with this
end in view that the present invention was conceived and devised.
My invention comprehends an instrument adapted to be attached to either or
both ends of the cylinder of well known forms of steam engines, and in practice I
use a small turbine or rotary motor actuated by one or more jets of steam or water,
directed through a jet pipe or nozzle and impinging upon the blades or buckets
thereof at its periphery or sides. The shaft of this turbine or rotary motor is con-
nected mechanically to a dynamometer which will balance or measure the force
given by the jet or jets of steam or water, and the scale of the dynamometer may
be either graduated in the ordinary manner, as is customary in calibrating steam
gauges, or it may be calibrated empirically from actual tests, thus indicating the
desired units of energy, such for instance as mean effective pressure or horse power.
The well known formula for calculating the energy of an engine contemplates
the multiplying the area of the piston head in square inches by the mean effective
pressure and the multiplication of this product by the distance travelled in feet
per minute, which total product is divided by 33,000 ft. pounds. The area of the
piston head and 33,000 ft. pounds being constant, the quantities to be measured
are, therefore, the mean effective pressure and the velocity in feet per minute.
The latter is easily obtained by measuring the revolutions per minute of the shaft
of the engine and multiplying the same by twice the length of the stroke in feet;
but, as above explained, the measurement of the mean effective pressure involves
the described method of tracing a diagram with an indicator.
Referring now to the drawings in detail, in all of which like letters of reference
represent like parts wherever used.
A represents a cylindrical metallic enclosing casing secured directly to a cylin-
drical motor chamber B₁ having a detachable head B secured thereto by
screws nnnn, said parts when united constituting a steam chamber for a rotary
turbine or motor T of disc form, having one surface provided with radially disposed
buckets or vanes 9 g, said motor being secured to a shaft S by a hub S3 and provided
with ball bearings bbbb secured in the well known manner in a stationary hub S²,
by cones and cups, as clearly illustrated in the drawings, see Figure 1. tttt are pairs
of nozzles secured to the upper ends of steam tight collars K K, see Figures 5 and 6,
said nozzles being arranged at suitable angles for directing the flow of the steam
or other motive agent against the buckets or vanes gg of the motor T. These
nozzles are preferably constructed as shown in Figure 54, in which the steam or
other motive agent is emitted or ejected through an orifice v having substantially
the conformation shown. I have found that the ordinary tapering nozzles, as
usually constructed, will become coated interiorly with a deposit of partially
carbonized oil, thus effectually choking or clogging them up, and the form of con-
struction shown in Figure 54 of the drawings will effectually overcome this defect.
www¹ w¹ are screens carried at the outer ends of segments w² w³, supported in turn
by arms VV pivoted to the collars K K by shoulder screws V₁ V₁, the arrange-
ment being such that when the screens ww are out of the path of their correspond-
ing nozzles tt the other pair w¹ w¹ will be directly in the path of their corresponding

page_text: nozzles t't' and vice versa. Y is a yoke having its opposite ends pivotally con-
nected with the free ends of the arms VV, the middle of said yoke being in turn
connected to a reciprocating rod I having vertical movement in a guide or sleeve d
secured in the detachable head B, see Figure 1.
12 13 is a bell crank lever secured to the detachable head B at I, the free end of
the arm I of said bell crank lever extending into a slot in the reciprocating rod I,
to which it is pivotally connected by a pin as shown, see Figures 1 and 6. The arm I³
is pivotally attached at 15 to a rod R¹ provided with an adjustable turn buckle TB,
connected in turn to the upper end of a lever L2 pivotally supported by an adjust-
able fulcrum AF to a stanchion or standard ST rigidly secured to the bed-plate of
the engine SE, see Figure 7. To the lower end of the lever L2 is secured a rod R³
adapted to move in longitudinal directions through a bearing or support m, secured
to one of the engine guides EG; gq being collars or tappets adjustably secured to
the rod R, E B being a lug or projection secured directly to the cross-head CH of
the engine and adapted to engage said tappets at the termini of the strokes.
KK are pipes running from the opposite ends of the cylinder of the engine to
the inlet collars KK, said pipes being connected to the inlet collars by the screw
threaded portions PP, see Figure 5. C3 C3, Figure 7, are three-way cocks in the
pipes K¹K¹ for enabling one to apply the ordinary steam engine indicators in
the usual manner. E is the exhaust pipe of the apparatus which may lead into
the open air or into the exhaust of the engine, as is desired. C is a cup or receptacle
secured to the upper part of the instrument and connected to a tube c running to
the interior chamber of the ball bearings 6 of the motor, its function being to
supply a solvent material to said bearings for the purpose of preventing a coating
or deposit thereon of the carbonized oil, which is carried into the ball bearing
chamber by steam from the engine.
I have found in experimenting with and using my instrument in connection with
steam engines that the lubricants supplied to the cylinder of such engines become
partially decomposed or volatilized by the high temperature of the steam and that
such decomposed or volatilized lubricants will deposit in the form of a coating upon
the balls of the ball bearings, therefore increasing their diameter and ultimately
effectually preventing the operation of the instrument, and it was with a view of
rendering the operation of the instrument more perfect that I supply a means of
preventing the same in the nature of the cup C and its contained solvent liquid,
such for instance as a potash solution or any hydrocarbon oil. C¹ is an adjusting
screw for regulating the outflow of the solvent as desired.
F is a rotary fan having two or more blades or vanes secured by screws to a
hub f, as shown, which in turn is secured to one end of the shaft S, see Figures 1
and 2, said fan being adapted to rotate within the cylindrical casing A. F¹ is a
second fan adjacent to and similar in all respects to the fan F and secured by
a hub f to a second shaft s2, which in turn is provided with ball bearings 6161
secured in the usual manner in cones and cups carried by metallic discs D4 D5,
fitting snugly within the inner surface of the casing A and separated from each
other by pillars pp.
H is a dial hand secured to the shafts by a nut s¹ and s is a retractile spring
having one end secured to the shaft 2 by a hub h and the other to a pillar or post
carried by a magnetic disc D2, supported in turn beneath the springs by a series
or radially disposed arms D³ attached to the disc D4 by screws, as shown, the func-
tion of the disc D² being to prevent the springs from becoming permanently
magnetized.
D' is a Foucault disc of copper or other metal secured to the shaft 2 by the hub h
and adapted to rotate between the poles of one or more permanent magnets M M M M
secured to the disc D, its function being to steady the dial hand from undue
fluctuations. D is the dial secured to the outer surface of the disc D by screws,
as shown in Figures 1 and 3 of the drawings, said dial being calibrated to the
desired units, such for instance as pounds pressure per square inch.
eee, Figure 3 are adjustable indices adapted to be moved independently around

page_text: the periphery of the dial, said indices being provided with individual numbers
illustrated in the drawings as running from 20 to 280. In Figures 3* and 3º I
have illustrated these indices in detail, e3 being a metallic clip integral with
a pointer e¹ to which is pivotally secured the disc e for the numerals by a rivet e²,
the arrangement being such that when said indices are shifted or adjusted to
different positions said discs may be individually rotated, in order that the
mumerals thereof may always stand in a legible position. These indices are
attached to the dial D by slipping clips e³ over the outer edge of the dial, there
being sufficient friction between the dial and the clips to maintain them in any
position in which they may be set. The function of the outer scale of indices e
is to provide an approximate indication of horse power units when the instrument
is attached to an engine. G is a glass cover enclosing the dial D and attached
parts, said cover being secured to the enclosing casing A by a ring or rim R
and screws 0 0.
My invention depends for its operation upon the fact that I utilize or absorb
a portion of the steam or motive agent which is given to the cylinder of the prime
mover or engine, in such manner as to drive a motor having sufficient moment
of inertia to enable it to run at a practically constant velocity for successive
impulses of equal values in pressures and durations, which motor in turn drives
indicating mechanism adapted to indicate directly, in established units, the
power or pressure utilized to drive the prime mover or engine itself and this
is accomplished by causing the steam, which successively enters the cylinder at
the opposite ends behind the piston, to continuously drive a rotary motor T
having a sufficient moment of inertia and adapted to perform a definite amount
of work proportionate to the work performed by the prime mover or engine, the
power of which it is desired to ascertain, and in the application of this generic
principle of measuring a definite proportion of power used and giving a direct
visual indication of the same lies the essence of my invention. It is a well
established fact in the operation of steam engines that there is a wide variation
of pressure in the cylinder upon the piston between the beginning and ending of
each complete stroke and that the mean effective pressure upon the same, which
is the quantity to be measured, is the resultant of the mean or average pressure
on one side minus the mean or average pressure on the opposite side, the latter
being due to the resistance of the exhaust and to compression "after the
exhaust valves are closed.
$6
"
"
"
I will now describe the operation of my invention reference being had to
Figure 7 of the drawings in which the steam is presumed to be driving the piston
from left to right in the direction of the arrow, the effect thereof on said piston
being indicated by the character "+." At the same time there is back pressure
caused by the steam in the other end of the cylinder against the opposite side
of the piston, which pressure is indicated by the character " and is due to
the resistance of the "exhaust" and " compression" after the exhaust valve is
closed. These pressures indicated by " +
and "
characters are varying
within wide limits; for instance, supposing that steam be admitted to the
evlinder at say 80 pounds pressure to the square inch and that at two-tenths of
the stroke the valve closes. The steam now expands; driving the piston forward to the
end of the stroke, its pressure falling by a well known law to say 5 pounds. A
definite proportion of the steam now passes upward in the direction of the vertical
arrow. through the pipe K¹, three-way cock C³ and the lower nozzle t impinging
ubon the buckets or vanes g of the rotary motor T, tending to impart motion thereto
in the direction of the arrow. At the same time the back pressure indicated by
the character " in the right hand end of the cylinder causes a definite pro-
portion of the steam to pass upward therefrom through the pipe K' in the direction
of the vertical arrow, through the three-way cock C², lower right hand nozzle
impinging against the buckets or vanes of the rotary motor T, tending to retard
the forward motion thereof, with the result that the rotary motor, due to its inertia
"

page_text: and the arrangement of the nozzles, rotates in a direction and at a velocity which
is the resultant and a measure of the mean effective pressure of the two forces.
It will be apparent, therefore that whatever may be the action of the steam upon
the opposite sides of the piston during its stroke, there will be a corresponding
proportionate action upon the opposite faces of the buckets or vanes of the rotary
motor, as will be obvious on inspection of Figure 5 of the drawings. As the piston
approaches the end of its stroke the lug or projection E B carried by the cross-
head CH comes into mechanical contact with the right hand tappet q carried by
the rod R, so that the further advancement of the piston imparts to the lower end
of the lever L³ movement to the right and to its upper end a movement to the left,
thereby causing the rod R¹ to give to the arms 13 Is of the bell crank lever a
corresponding movement, to the reciprocating rod I and yoke Y a downward move-
ment, and to the arms VV a rotary movement sufficient to cause the segmental
screens tow to close the nozzles tt and at the same time remove the screens 10¹ w¹
from before the nozzles t¹t, see Figure 6. Consequently, as steam enters the right
hand end of the cylinder the pressures indicated by the
"
"and
+
-" characters
in Figure 7 of the drawings are reversed and in like manner a corresponding pro-
portion of the steam now impinges upon the buckets or vanes of the motor
through the upper nozzles t¹¹, tending to impart motion to the rotary motor T
in the same direction as before and with a like resultant effect, due to the action of
the steam from both of said nozzles. In like manner, when the piston approaches
the extreme left hand stroke, the lug or projection EB comes into mechanical con-
tact with the left hand tappet q and reverses the action of the parts, thus completing
one cycle. These operations continue successively so long as the engine is running.
Referring now to Figures 1, 2, 3 and 4 for a detail description of the operation
of the indicating instrument, it will be apparent that when the rotary motor T
is set in motion the fan F, mechanically connected thereto, imparts motion to the
air within the fan chamber, thereby tending to rotate the second or independent
fan F in the same direction against the retractile force of the springs and causing
the dial hand H to assume a definite angular deflection over the scale of the dial D,
proportionate to the velocity of the fan F, the magnets M acting as a damper, in
a well understood manner, upon the Foucault disc D¹.
In the event of any variation of load being put upon the engine there results
a corresponding variation of pressure in the cylinder thereof and, consequently, a
proportionate variation in effect will be given to the motion of the motor; in as
much as the deflection of the dial hand H is a measure or indication of the velocity
of the rotary motor T, which in turn is a measure of the mean effective pressure on
the piston, said dial hand will give a deflection corresponding to these variations.
In calibrating the instrument for the fixed or M.E.P. (mean effective pressure)
scale indicated by the numerals 10, 20, 30 to 90 inclusive, Figure 3 of the
drawings, it is attached to a steam boiler or compressed air reservoir provided with
a standard pressure gauge and steam or compressed air allowed to flow through
one nozzle t only, at definite pressures, in such manner as to drive the motor T in the
proper direction, the deflection of the dial hand being noted and marked on the dial
at the corresponding pressures, 10, 20, 30 to 90 inclusive, as indicated by the
standard pressure gauge, after which they are sub-divided, as shown, into smaller
units.
"
"
If now the instrument be attached to a steam engine and operated in the manner
shown in Figure 7 of the drawings, as hereinbefore described, it will be found that
the variable pressures due to the action of the steam, as indicated by the " +
and " characters in Figure 7, will give to the indicating hand a deflection which
corresponds to the mean effective pressure upon the piston. In other words, if the
dial hand H gives a definite deflection, say 30, it will be found that the mean
effective pressure on the piston at that time is 30 pounds, if measured independently
in the well known way by a steam engine indicator."
"
Referring now to the outer scale, bearing numbers from 20 to 280 and as
designed to indicate approximately the horse power for different pressures, I will

page_text: describe the function and manner of use thereof. In all self-governing steam
engines the speed is practically constant and an instrument that will measure and
indicate the mean effective pressure thereof can be calibrated so as to read in units
of horse power, in as much as the other quantities are constant with the exception of
the mean effective pressure which is to be measured, and this will vary in propor-
tion to the total energy of horse power. Bearing this in mind it is an easy matter
to provide an adjustable scale which may be set to indicate definite horse powers
for definite pressures when the engine is run at a constant speed.
Suppose for instance, that the instrument be attached to an engine having a
piston area of 176 square inches, travelling at a velocity of 500 feet per minute and
that the mean effective pressure thereon for a given load equals 30 pounds. By
the well known formula for calculating the horse power of an engine,and herein-
before referred to, the calculated horse power would equal 80; therefore, a movable
index having the numeral 80 and adjusted opposite the Figure 30 on the scale
would indicate that a mean effective pressure of 30 pounds on the piston running
at that speed would equal 80 horse power. The same process is gone through for
the remaining individual indices with the result that an outer horse power scale
may be adjusted for the conditions, as to speed, under which the engine is working.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. A mean effective pressure indicator for steam or analogous engines consisting of
a continuously driven motor actuated directly by a part of the steam which drives the
engine, and having sufficient moment of inertia to render its velocity substantially
constant for successive impulse effects of the steam, when said impulses are of equal
value in average pressure and duration, and an indicator driven by the motor and
adapted to give visual indications of a unitary nature.
2. A mean effective pressure indicator consisting of a rotary motor having
sufficient moment of inertia to render its velocity substantially constant for suc-
cessive impulses of the motive agent, said motor being attached to a rotary fan;
in combination with a second fan adapted to be propelled by the first named fan
and an indicating hand carried by a shaft which sustains the second fan; means
as a retractile spring for retarding or opposing the forward movement of said fan,
together with a dial calibrated to read units of measurement.
3. A mean effective pressure indicator for steam or analogous engines consisting
of a rotary motor actuated directly by a part of the motive agent which drives the
engine, and having sufficient moment of inertia to render its velocity a measure of
the mean effective pressure of the successive impulses of such motive agent, in
combination with an indicator driven by the motor and adapted to give visual
indications of a unitary nature.
4. A mean effective pressure indicator consisting of a rotary motor having a
sufficient moment of inertia to render its velocity a measure of the mean pressure
applied to the piston, in combination with means adapted to convey a part of the
motive agent directly from the cylinder of the engine to the rotary motor at the
same time that it is applied to the piston of the engine; together with means
driven by the motor for indicating definite units of pressure or energy.
5. A mean effective pressure indicator consisting of a rotary motor having a
sufficient moment of inertia to render its velocity a measure of the mean pressure
applied to the piston, in combination with two or more nozzles adapted to direct a
part of the motive agent from the cylinder of the engine to the rotary motor, said
nozzles being so arranged that the velocity of the motor is the resultant of two
forces acting in opposing directions.
6. A mean effective pressure indicator, consisting of a rotary motor having
sufficient moment of inertia to render its velocity a measure of the mean pressure
applied to the piston, in combination with two or more nozzles adapted to direct a
part of the motive agent from the cylinder of the engine to the rotary motor;

page_text: together with means for alternately opening and closing the nozzles at the termini
of each stroke of the engine.
7. A mean effective pressure indicator consisting of a rotary motor having
sufficient moment of inertia to render its velocity a measure of the mean pressure
applied to the piston, in combination with two or more nozzles adapted to direct
a part of the motive agent from the cylinder of the engine to the rotary motor,
said nozzles having each a discharge orifice of minimum longitudinal surface, as
shown, and so arranged that the direction of rotation of the motor and its velocity
is the resultant of two forces acting in opposing directions.
8. A mean effective pressure indicator consisting of a rotary motor having
sufficient moment of inertia to render its velocity a measure of the mean pressure
applied to the piston in combination with means for conveying to the ball bearing
chamber a solvent, such as a potash solution or a hydrocarbon oil, whereby the
decomposed products of the lubricants used in the engine and entering the ball
bearing chamber are prevented from being deposited upon the ball bearing
surfaces.
9. In a mean effective pressure indicator a dial having a fixed scale calibrated
to units of a definite nature, in combination with an adjustable scale calibrated to
units bearing a mathematical relation to the calibrations of the first named scale.
10. In a mean effective pressure indicator a dial having a fixed scale calibrated
to units of mean effective pressures, in combination with an adjustable scale adapted
to indicate units of energy.
11. An index for a mean effective pressure indicator consisting of means for
adjusting it relatively to a fixed scale and provided with a numeral indicating
surface adapted to be rotated so as to maintain the numerals thereon always in a
legible position.
Dated this 20th day of July 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.