Sale of Governors. Visit from Mr. Allen. Operation of the Engine Sold
to Easton, Amos & Sons. Manufacture of the Indicator. Application on
Locomotives.
The governor seemed to please every one. In anticipation of a demand
for them, I had shipped a number to London, which met a ready sale.
The most appreciative persons as a class were the linen-manufacturers
of Belfast. One of them early took a license to sell them there. The
first one I sold in London was to my friends Easton, Amos & Sons. As
soon as they saw it in operation it struck them as the very thing they
needed. In connection with their engineering works they carried on the
manufacture of lead pipe by hydraulic pressure. The engine which drove
a large section of their machine tools also drove the hydraulic pumps
for this manufacture. It was a very trying service. The resistance was
very heavy and came on and off the engine instantly. The action of the
common governor was not prompt enough to control it, and they had to
employ a man handling a disk valve with a very short motion. He had to
keep his eye fixed on a column of mercury. When this rose he must open
the valve, and when it dropped he must shut it. It had been found that
this was a poor reliance for the instantaneous action required. They
got a governor from me at once. I received a message from them the next
day. The governor would not answer at all; would I come down and see
about it? I happened first to meet an old man, foreman of the turners.
“What is the matter?” “Matter! The governor won’t work, that’s what’s
the matter.” I was rather an impulsive young man and replied, “It will
work, or I’ll eat it.” He sharply responded, “If it does work I’ll eat
it, and I haven’t a tooth in my head.” Foolish old man! he was more
rash than I. I saw at a glance that the governor went through but half
its action. There was evidently some resistance in the valve, a common
fly-throttle. After they shut down at night I had the valve pulled out,
and found that the chamber was larger than the pipe and that the wings
of the valve were long and their points caught on the ends of the pipe.
The wings of the valve were soon shortened and rebedded in the chamber,
and when started again the governor controlled the motion of the engine
perfectly, to the great gratification of everybody, and the delight
of the boys, who had heard the old man promise to eat it. The valve
had been put in for my governor to work, and the fitters had put up a
job on me. The old man was not in the secret. So the laugh was on him
instead of on me.
Directly after this triumph I received an order from Mr. John Penn
for a governor to regulate the engine driving his marine-engine works
at Greenwich. This was the first and only engine I ever saw of the
grasshopper class, quite common, I learned, in earlier days. The
superintendent of his works afterwards told me, laughingly, that he
had a large account against me for loss of time; that he had become
so fascinated with the governor action that he had stood watching it
sometimes for twenty minutes. He knew by the position of the governor
every large tool that was running and what it was doing, if light or
heavy work, and especially every time a planer was reversed.
One day a gentleman asked me if I thought the governor could regulate
his engine. He was a manufacturer of the metal thread used in making
gold lace. A bar of silver, 2 inches in diameter and 2 or 3 feet long,
was covered with three or four thicknesses of dentists’ gold leaf,
and then drawn down to exceedingly fine threads, and the gold surface
was never broken. I have often wondered how thick that gold covering
finally was. The heavy drawing of the cold bars required a great deal
of power, and when they shot out the engine would run away and the fine
threads would be broken. No governor nor heavy fly-wheel would help
the matter, and they had to do their heavy drawing in the night. My
governor maintained the motion absolutely. Not only were the finest
threads not broken by the sudden changes in the heavy drawing, but the
occasional breakages that they had been accustomed to nearly ceased.
In this connection I cannot refrain from telling a good story on Mr.
Ramsbottom and Mr. Webb, although the incident happened the next year.
I received an order for a governor for the engine driving the shops of
the London & Northwestern Railway at Crewe. Soon after its shipment
there came a line from the office there that the governor was behaving
badly and I would have to go and see about it. I found that the engine
consisted of a pair of locomotive cylinders set upright on the floor
and directly connected above, the cranks at right angles with each
other, to the line-shaft, a plan which I have always admired, as a
capital way of avoiding belts or gearing. They were running at 120
revolutions per minute, and were connected in the middle of the shaft,
which was about 400 feet long. The governor was flying up and down
quite wildly. I had never seen such an action before, and was at a
loss what to make of it. I saw no fly-wheel, but it did not seem that
its absence could account for this irregularity. Indeed, with coupled
engines running at this speed, and only trifling changes of load, and
a governor requiring no time to act, a fly-wheel seemed superfluous.
Pretty soon it came out that the want of fly-wheel could not cause the
trouble, for they had two. Where were they? There was one at each end
of the shaft, close to the end walls of the building, where wall boxes
afforded excellent supports. Fly-wheels at the ends of 2-inch shafts
and 200 feet from the engine! I fairly shouted with laughter, told
them to take off their fly-wheels, and came home. The fly-wheels were
taken off, and there was no further trouble. Well, what should railway
engineers, absorbed in locomotive designs and everything pertaining
to railroading, be expected to know about fly-wheel inertia and shaft
torsion?
About midsummer I had the pleasant surprise of a visit from Mr. Allen,
whose gratification at the show I had made was unbounded. We saw much
of the exhibition together. Perhaps the most interesting exhibits in
the machinery department, to us both, were the working models shown
by the marine-engine builders. There were a large number of these,
generally not much over one foot in any dimension, but complete to
every bolt and nut, superbly finished, and shown in motion. They had
evidently been made regardless of cost. In the progress of engineering
science, everything represented by these elegant toys has long since
vanished. We were much impressed by a cylinder casting, 120 inches in
diameter, shown by Mr. Penn, one of a pair made for a horizontal engine
for a British warship, to work steam at 25 pounds pressure. Everything
there shown pertaining to steam engineering, except our own engine, was
about to disappear forever. How long before that also shall follow?
Soon after Mr. Allen’s return he sent me a drawing of his four-opening
equilibrium valve with adjustable pressure-plate. I realized the great
value of this most original invention, now so well known, but its
adoption required a rescheming of the valve-gear, and that had to be
postponed for some years.
In setting up the engine in the works of Easton, Amos & Sons, I had
a curious example of English pertinacity. Old Mr. Amos said to me,
“Porter, where is your pump?” “The engine has no pump.” “No pump!” “No,
sir; we consider a feed-pump as an adjunct to the boiler, never put it
on the engine, and generally employ independent feed-pumps which can
be adjusted to the proper speed. Besides, a feed-pump could not be run
satisfactorily at the speed of this engine.” He heard me through, and
then, with a look of utter disgust, exclaimed: “If a man should sell
me a musket and tell me it had no stock, lock, or barrel, these were
all extra, I should think it just about as sensible.” Nothing would do
but that this engine must have a pump. I had intended to cut off the
projecting end of the shaft, but Mr. Amos ordered this to be left, and
had an eccentric fitted on it, and set a vertical pump on the floor to
be driven by this eccentric, at 225 double strokes per minute. Also the
feed-pipe had to be over 50 feet long, with three elbows.
Of course, as the boys say, we had a circus. A mechanic had a daily
job, mornings, when the engine was not running, securing that pump
on its foundation. The trembling and pounding in the feed-pipe were
fearful. I suggested an air-chamber. They sent word to me that they had
put on an air-chamber, but it did no good. I went to look at it, and
found a very small air-chamber in the middle of the length of the pipe,
where it seemed to me more likely to do harm. At my suggestion they
got one of suitable size and attached it to the pump outlet, when the
noise and trembling mostly disappeared, as well as the disposition of
the pump to break loose. It did fairly well after that, and they made
it answer, although I do not suppose it ever one quarter filled.
Mr. Amos was the consulting engineer of the Royal Agricultural Society.
At this exhibition American reapers made an invasion of England. Mr.
Amos set his face against them, and in reply to my question, what
objection he made to them, he said, “We prefer to get our grain into
the barn, instead of strewing it over the field.” And yet this man, the
engineering head of this firm, was the only man in England, so far as I
knew, advanced enough to take up the Wolff system of compounding, and
who had bought my engine to run at 225 revolutions per minute, which it
continued to do with complete satisfaction until some years later, when
these works were removed to a location on the Thames, east of London,
when I lost sight of them.
During the latter part of the exhibition I learned that the McNaught
and the Hopkinson indicators were in common use in England; that one or
both of these were to be found in the engine-rooms of most mills and
manufacturing establishments, and that if the Richards indicator were
properly put on the market there would probably be some demand for it,
although at existing engine speeds the indicators in use appeared to
be satisfactory. A special field for its employment would doubtless
be found, however, in indicating locomotives. I felt sufficiently
encouraged to set about the task of standardizing the indicator, and
during the winter of 1862-3 made a contract with the firm of Elliott
Brothers, the well-known manufacturers of philosophical apparatus and
engineering and drawing instruments, to manufacture them according to
my plans.
This was my first attempt to organize the manufacture of an instrument
of any kind, and I set about it under a deep sense of responsibility
for the production of an indicator that should command the confidence
of engineers in its invariable truth. I found that the opportunity I
had enjoyed for studying the subject had been most important. The daily
use of the indicator which I had brought to the exhibition was an
invaluable preparation for this work.
I decided, first, to increase the multiplication of the piston motion,
by means of the lever, from three times to four times, thus reducing
by one quarter the movement of the piston required to give the same
vertical movement to the pencil, and, second, to increase the cylinder
area from one quarter to one half of a square inch. The latter was
necessary in order to afford sufficient room for springs of proper
size, and correct reliable strength in their connections.
The first problem that presented itself was how to produce cylinders
of the exact diameter required, .7979 of an inch, and to make an error
in this dimension impossible. This problem I solved in the following
manner: At my request Elliott Brothers obtained from the Whitworth
Company a hardened steel mandrel about 20 inches in length, ground
parallel to this exact size and certified by them. Brass tubes of
slightly larger size and carefully cleaned were drawn down on this
mandrel. These when pressed off presented a perfect surface and needed
only to be sawed up in lengths of about 2 inches for each cylinder.
Through the whole history of the manufacture that removed all trouble
or concern on this account.
The pistons were made as light as possible, and were turned to a gauge
that permitted them to leak a little. The windage was not sufficient to
affect their accuracy; a thickness of silk paper on one side would hold
the pistons tight; but they had a frictionless action, and the cover of
the spring case having two holes opening to the atmosphere, there could
be no pressure above the piston except that of the atmosphere.
[Illustration:
SPRING-TESTING INSTRUMENT.
USED IN THE MANUFACTURE OF THE RICHARDS INDICATOR.
Designed by Charles T. Porter.
LONGITUDINAL SECTION.
SCALE, HALF SIZE.
END VIEW]
The second problem was to insure the accuracy of the springs. This was
more serious than the first one. The brass heads of the springs were
provided with three wings instead of two, which mine had. The spring,
after being coiled and tempered, was brazed into the grooves in the
first two wings, and the third wing was hammered firmly to it. This
prevented the stress on the spring from reaching the brazed joints,
and these heads never worked loose. One head was made fast at once;
the other was left free to be screwed backward or forward until the
proper length of the spring was found. To insure freedom from friction,
I determined to adjust and test the springs in the open air, quite
apart from the instrument. For this purpose I had a stout cast-iron
plate made, with a bracket cast on it, in which the slides were held
in a vertical groove, and bolted this plate on the bench, where it was
carefully leveled. The surface of the plate had been planed, a small
hole drilled through it at the proper point, and a corresponding hole
was bored through the bench. A seating for the scales also was planed
in the bracket, normal to the surface of the block. The spring to be
tested, in its heads as above described, was set on the block, and a
rod which was a sliding fit in the hole was put up through the bench,
block, and spring. This rod had a head at the lower end, and was
threaded at the upper end. Under the bench a sealed weight, equal to
one half the extreme pressure on the square inch to be indicated by the
spring, was placed on the rod.
Between the spring and the scale I employed a lever, representing that
used in the indicator, but differing from it in two respects. It was of
twice its length, for greater convenience of observation, and it was
a lever of the first order, so that the weight acting downward should
represent the steam pressure in the indicator acting upward.
The weight was carried by a steel nut screwed on the end of the rod and
resting on the upper head of the spring to be tested. This nut carried
above it a hardened stirrup, with a sharp inner edge, which intersected
the axis of the rod, produced. A delicate steel lever was pivoted to
turn about a point at one fifth of the distance from the axis of the
rod to the farther side of the scale seat. The upper edge of this lever
was a straight line intersecting the axis of its trunnions. The short
arm of the lever passed through the stirrup, in which it slid as the
spring was compressed, while the long arm swung upward in front of the
scale. The latter was graduated on its farther side, and the reading
was taken at the point of intersection of the upper edge of the lever
with this edge of the scale.
The free head on the spring was turned until the reading showed it to
be a trifle too strong. It was then secured, and afterwards brought
to the exact strength required by running it rapidly in a lathe and
rubbing its surface over its entire length with fine emery cloth.
This reduced the strength of each coil equally. This was a delicate
operation, requiring great care to reduce the strength enough and not
too much. A great many springs had to be made, several being generally
required, often a full set of ten, with each indicator. This testing
apparatus was convenient and reliable, and the workmen became very
expert in its use.
The spring when in use was always exposed to steam of atmospheric
pressure. At this temperature of 212° we found by careful experiment
that all the springs were weakened equally, namely, one pound in forty
pounds. So the springs were made to show, when cold, 39 pounds instead
of 40 pounds, and in this ratio for all strengths.
This system of manufacture and testing was examined in operation by
every engineer who ordered an indicator, the shop on St. Martin’s Lane
being very convenient. They generally required that the indicator
should be tested by the mercurial column. The Elliotts, being large
makers of barometers, had plenty of pure mercury, so this requirement
was readily complied with, and the springs were invariably found
to be absolutely correct. We never used the mercurial column in
manufacturing, but were glad to apply it for the satisfaction of
customers.
I employed the following test for friction. The indicator when finished
was set on a firm bracket in the shop. The spring was pressed down as
far as it could be, and then allowed to return to its position of rest
very slowly, the motion at the end becoming almost insensible. Then a
fine line was drawn with a sharp-pointed brass wire on metallic paper
placed on the drum. The spring was then pulled up as far as possible
and allowed to return to its position of rest in the same careful
manner. The point must then absolutely retrace this line. No indicator
was allowed to go out without satisfying this test. The workmanship was
so excellent that they always did so as a matter of course.
Mr. Henry R. Worthington once told me, long after, that on the test of
an installation of his pump in Philadelphia, after he had indicated it
at both steam and water ends, the examining board asked him to permit
them to make a test with their own indicator, which they did the next
day. They brought another indicator, of Elliott’s make like his own,
but the number showed it to have been made some years later. “Would you
believe it,” said he, “the diagrams were every one of them absolutely
identical with my own!” I replied that the system of manufacture was
such that this could not have been otherwise.
[Illustration: Plan of Spring-testing Instrument.]
I wish to acknowledge my obligation to Elliott Brothers for their
cordial co-operation, their excellent system of manufacture, and the
intelligent skill of their workmen, by one of whom the swiveling
connection of the levers with the piston-rod was devised.
The indicator was improved in other important respects, but I here
confine myself to the above, which most directly affected its accuracy.
This soon became established in the public confidence. During my stay
in England, about five years longer, the sale of indicators averaged
some three hundred a year, with but little variation. The Elliotts
then told me that they considered the market to have been about
supplied, and looked for a considerable falling off in the demand, and
had already reduced their orders for material. Eight years after my
return I ordered from them two indicators for use in indicating engines
exhibited at our Centennial Exhibition at Philadelphia. The indicators
had from the first been numbered in the order of their manufacture.
These came numbered over 10,000.
The indicators were put on the market in the spring of 1863, and I
sought opportunity to apply them on locomotives. In this I had the
efficient co-operation of Zerah Colburn, then editor of _The Engineer_.
The first application of them was on a locomotive of the London and
Southwestern Railway, and our trips, two in number, were from London
to Southampton and return. The revelations made by the indicator were
far from agreeable to Mr. Beattie, the chief engineer of the line. Mr.
Beattie had filled his boilers with tubes ⁷⁄₈ of an inch in diameter.
The diagrams showed the pressure of blast necessary to draw the gases
through these tubes to average about ten pounds above the atmosphere,
the reduction of the nozzles producing this amount of back pressure
throughout the stroke. Another revelation was equally disagreeable.
The steam showed very wet. We learned that Mr. Beattie surrounded his
cylinders with a jacket. This was a large corrugated casting in which
the cylinder was inserted as a liner. To keep the cylinder hot the
_exhaust_ was passed through this jacket. Mr. Colburn made both of
these features the subjects of editorials in _The Engineer_, written
in his usual trenchant style. The last one was entitled “Mr. Beattie’s
Refrigerators,” and produced a decided sensation.
Our next trips were made on the Great Eastern Road, one from London to
Norwich and one from London to Great Yarmouth. On these trips we were
accompanied by Mr. W. H. Maw, then head draftsman of the Great Eastern
Locomotive Drawing Office, under Mr. Sinclair, the chief engineer, and
by Mr. Pendred. These gentlemen were afterwards, respectively, the
editors of _Engineering_ and _The Engineer_.
[Illustration: Diagrams from English Locomotives taken with Richards
Indicator.]
The diagrams from the Great Eastern engines were, on the whole, the
best which were taken by us. On one of these trips I was able to
get the accompanying most interesting pair of diagrams, which were
published by me in the appendix to my treatise on the Indicator. One of
them was taken at the speed of 50 revolutions per minute, and the other
at the speed of 260 revolutions per minute, running in the same notch
with wide-open throttle. The steam pressure was higher at the rapid
speed. They afford many subjects of study, and show the perfect action
of the indicator as at first turned out, at this great speed. I learned
afterwards that the almost entire freedom from vibration at the most
rapid speed was due to the gradual manner in which the pressure fell
from the beginning of the stroke. This fall of pressure before the
cut-off I fancy was caused largely by a small steam-pipe.
Our last diagrams were taken from a locomotive on the London and
Northwestern, by the same four operators as on the Great Eastern trips.
We ran from London to Manchester. On our return trip Mr. Webb joined us
at Crewe, and accompanied us to London. I am sorry to say that in one
respect the revelation of the indicator here was almost inconceivably
bad. Mr. Ramsbottom did not protect his cylinders, but painted these
and the steam-chests black, and in this condition sent them rushing
through the moist air of England. If the steam cooled by “Mr. Beattie’s
refrigerators” was wet, that in Mr. Ramsbottom’s cylinders seemed to
be all water. A jet of hot water was always sent up from each of the
holes in the cover of the spring case to a height of between one and
two feet. We had much trouble to protect ourselves from it, and it
nearly always drenched the diagram. I never saw this phenomenon before
or since. I have seen the steam blow from the indicator cocks white
with water when the indicators were removed. But I never saw water
spurt through the spring-case cover, except in this instance. Truly, we
said to each other, Mr. Ramsbottom has abundant use for his trough and
scoop to keep water in his tanks. It was on this trip that I observed
how enormously the motion of a black surface increased the power of
the surrounding air to abstract heat from it. While we were running
at speed I many times laid my hand on the smoke-box door without
experiencing any sensation of warmth. I wondered at this, for I knew
that a torrent of fire issuing from the tubes was impinging against
the opposite surface of this quarter-inch iron plate. In approaching
Rugby Junction I observed that the speed had not slackened very much
when I could not touch this door, and when we stopped, although the
draft had mostly ceased, I could not come near it for the heat. At the
full velocity with which the air blew against this door the capacity of
the air to absorb heat evidently exceeded the conducting power of the
metal.
[Illustration: W. H. MAW]