The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1891-09-06
NEW ADAPTATION
OF old IDEAS
Steam and Heated Air in Conjunction
will OutW0rk Steam.
A Basic Idea Upon Which to Found an Electro
cal Theory-Practical Application Of
New Force to Machinery.

IL is we'll known tnat the practical ell
| cheney of the steam engine is very far be-
| low the standard which theory correctly
| sets up for it. The mechanical work done
| by pound of coal In our best engines-that
| is, by the conversion of heat into motion
| is greatly less than theory tells us it should
| be, says the London Times 1t has been
| proposed to supersede steam by various
| gases, or to add them to it and use them in
4 mixed form. Air has found much favor
with inventors. and there have been times
when the use of combined air and steam
appeared to be a practical method of i'm
proving the steam engine. But, apart from
gas engines and hot-air engines pure and.
simple, down to the present time there has
been n record of commercial or even prae-
tical success having attended the introduce
ton of air in any way into the steam
engine.
Among others who have taken a deep
practical interest in the question of the use
of combined air and steam in the engine Is
Mr. Edward Field, C. E., who has been
well known for many years past in cOnnec-
ton with the steam boiler bearing his name.
His Improvement was a great step In adj
vance in the steam boiler, but it is probable
that it will be found that he has now made
far greater advance in the engine by i'll
creasing its efficiency and economy in a
very remarkable degree. And what he has
really done parta6es rather Of the nature OK
discovery than an invention.
Put in a few plain words. Mr.. Field pro-
duces the volume of mixed gases under pres
sure necessary for performing given
amount of work in an engine with the use
of only from 12h to 20 per cent of the guam
tity of steam which would be used in the
same engine to perform the same amount Of
work. II volume of mixed gases con-
sists of a suIall volume of steam introduced
into large volume of heated air.
WHATEVER OF INVENTION
There is in the present connection relates to
the apparatus by means of whirh the dis
covery is utilized in practice. This appara-
tus consists of two portionS-uamely, the
experimental, whereby Mr.. Field demon
strates the principles of his discovery, and
the practical, by which he illustrates the
application of those principles in doing work.
This apparatus Of both kinds we have re-
Gently had the opportunity of inspecting and
of seeing in operation with results which
fully support all that MIR. Field claims i'll
respect of the principle. The experimental
apparatus consists OF two measuring cham
bers of different capacities, and working
cylinder having weighted piston. In order
to prevent condensation or loss of heat a
high temperature is maintained In each of
the chambers. In order TO render the ex-
periments comparative, steam was first adj
mitted to both OF the measuring chambers
at a pressure of sixty pounds per square
inch. This steam, which represented
twenty volumes, was then admitted
to the working cylinder, and it raised
the piston, with a load of III pounds,
to height of five and one-half inches.
The experiment was repeated, when the
piston was only raised four and three
fourths inches. The smaller of the two
chambers was then half-fled with steam at
sixty pounds pressure, and the larger cham
Der with heated air at a temperature of
400 Fahrenheit, which is about the temper
AZURE required in practice and at atmO-
spheric pressure, as shown by the respec-
tive gauges The proportions were two Of
steam and sixteen of heated air, and upon
the admission of the steam to the air the
gauges on both chambers instantly showed
q pressure of sixty pounds per square inch.
UPON THE MIXTURE OF STEAM AND AIR
Being admitted to the cylinder the Weighted
piston was rapidly driven seven and half
inches. which was as high as it could reach,
and represented the stroke OF the cylinder.
Upon the experiment being repeated the
weighted piston rose much more rapidly
giving the cylinder covering violent blow.
A number of other experiments were made
with similar results. and, as whole. clearly
demonstrated that the twenty volumes Of
steam failed to do the work that two
volumes of steam combined with sixteen .
volumes of heated air did. They further
showed that the best results we're obtained
with these proportions of the two fluids,
and these are about the proportions which
Mr.. Field employs in practice.
1t should be observed that in practice the
air is heated at little or no cost by the waste
heat, which in an ordinary engine escapes
into the atmosphere.
The principles here involved have been
put in practice by Mr.. Field in portable
engine, which, however, has several draw
backs in consequence of the mixing chambers
having to be superadded to the existing en-
CINE works. These chambers are mounted
on the top of the engine cylinder, and there
is a chamber each oVlIn6nr.
Each of these chambers in turn receives its
charge of heated air. into which is delivered
pr0portiOnate charge Of steam. The mix
ture is delivered from each chamber alter
nately 10 the front and the back end of the
cylinder, causing the outstrokes and in
strokes of the piston in succession. Upon
the occasion of our visit the engine was first
run with steam alone and without load. 1t
was then run with compound steam and
heated air in about the proportions preyi-
0usly stated. The conditions under which
this run was made were the same as in the
previous run, and the same observations
were taken.
IT MAY BE MENTIONED
That the temperature in the air chamber
should not be less than 1000 Fahrenheit for
the proper development of the advantages
of the system. As matter of fact the air
temperature during the engine trials was
not higher than 300o, but was generally
much lower, owing TO the draughts and to
apparatus. On comparing the results of tho
two engine runs made respectively with
pure steam and with combined steam and
heated air, it was found that there was an
absolute gain of Al per cent in favor of the
Field system as against ordinary steam.
The system, as well as the experimental
apparatus, has been independently tested
by three engineers, namely, Mr.. COL
lett Homersham, c. E.; Mr.. d. K. Clark, C.
E., and Perry f. Nursey. G. E each of
whose reports substantates this economy
and points to still higher results with a
larger engine properly and efficiently fitted
with the necessary adjuncts for working
upon Mr.. Fields principle. This, in
fact, is what is now being done. and
in due cours the results will be ar
rived at and made known. Should they
confirm the results already attained-and
there does not appear TO be any reason why
they should not-Mr. Fields discovery can
not fail to produce complete revolution in
motive power. The opinion of this system
entertained by Mr.. ID. X. Clark, whose re-
port has already been referred to, may be
gathered by the following extract from that
document: 1t means an enormous COM
mercial success, If properly manipulated.
and under Mr.. Fields experienced super
vision it seems quite possible that this en-
| CINE will bring about the same benefit with
regard to the economical use OF steam as
| Bessemer's steel gave to its own specific
| industries"
Tu,n lar Gol1 Eafrn