A NEW OR IMPROVED COMPOUND STEAM ENGINE
Year: 1879

page_text: LETTERS PATENT to Charles Spruyt de Bay, of 9, Victoria Chambers, West-
minster, Civil Engineer, for the Invention of "A NEW OR IMPROVED
COMPOUND STEAM ENGINE."
Sealed the 23rd January 1880, and dated the 25th July 1879.
PROVISIONAL SPECIFICATION left by the said Charles Spruyt de Bay at
the Office of the Commissioners of Patents on the 25th July 1879.
CHARLES SPRUYT DE BAY, of 9, Victoria Chambers, Westminster, Civil Engineer.
"A NEW OR IMPROVED COMPOUND STEAM ENGINE."
This Invention has reference to compound engines in which the motive force acts
upon pistons of different areas, the smallest area receiving the highest pressure of
the motive force, which is afterwards expanded on the largest piston area before its
final release into the atmosphere or condenser. The object of this Invention is to
combine the cylinder of the ordinary engine where the piston moves in a rectilinear
direction with the cylinder of a rotary engine, so as to produce a compound engine
in which the bigh pressure cylinder will be of one class, and the low pressure
cylinder of the other class, that is, one with a rectilinear movement of piston, and
the other with a rotary movement of piston.
The low pressure engine would not be of any particular class of rotary engine, as
in the combination of the reciprocating high pressure and the rotary low pressure
whatever defects might exist in the rotary engine as used simply by itself as a high
pressure engine from leakage, friction, or other causes would be very considerably
modified when used as the low pressure part of a compound engine, as the piston
pressure would be considerably reduced. But though the Invention is not limited
to the combination of any particular class either of high pressure reciprocating or
low pressure rotary engines, but to any or all of them, I will briefly describe one
class of rotary engine which is very well adapted for the purpose of this Invention.
In this engine the cylinder which lies horizontal has in it parallel to its axis but
eccentric to its bore a revolving hollow drum having flanges at its ends, which
embrace the cylinder ends and fit over them, and which are grooved to support and

page_text: carry the pistons. The joint between the flanges and the cylinder ends is packed,
and the pistons have upon their ends legs which are carried in the grooves, and
which project beyond the body of the pistons. To the ends of these legs are
attached slides which travel on an outer ledge nearly concentric with the bore of
the cylinder, and which assist in keeping the pistons in steam tight contact with
the cylinder bore. Outside the flanges of the revolving drum are fixed covers
secured to the cylinder, completely enclosing all the working parts, and being also
constructed to carry the bearings of the engine shaft. The high pressure ordinary
piston engine is secured to a bed plate which also carries the rotary one, and the
shafts of the two engines can be either separate, and the power taken off each
separately, or the shafts may be coupled together and the power of both trans-
mitted through the one shaft.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Spruyt de Bay in the Great Seal Patent Office on the 24th
January 1880.
CHARLES SPRUYT DE BAY, of 9, Victoria Chambers, Westminster, Civil Engineer.
"A NEW OR IMPROVED COMPOUND STEAM ENGINE."
This Invention has reference to compound engines in which the motive force acts
upon pistons of different areas, the smallest area receiving the highest pressure of
the motive force, which is afterwards expanded on the largest piston area before its
final release into the atmosphere or condenser. The object of this Invention is to
combine the cylinder of the ordinary engine when the piston moves in a rectilinear
direction with the cylinder of a rotary engine, so as to produce a compound engine
in which the high pressure cylinder will be of one class, & the low pressure
cylinder of the other class, that is, one with a rectilinear movement of piston, and
the other with a rotary movement of piston.
The low-pressure engine would not be of any particular class of rotary engine, as
in the combination of the reciprocating high pressure and the rotary low pressure,
whatever defects might exist in the rotary engine as used simply by itself as a
high pressure engine from leakage, friction, or other causes would be very con-
siderably modified when used as the low pressure part of a compound engine, as
the piston pressure would be considerably reduced. But though the Invention is
not limited to the combination of any particular class, either of high pressure
reciprocating or low pressure rotary, but to any or all of them, I will briefly
describe one class of rotary engine, which is very well adapted for the purpose of
the Invention. In this engine the cylinder which lies horizontal has in it parallel
to its axis but eccentric to its bore a revolving hollow drum having flanges at its
ends, which embrace the cylinder ends and fit over them, and which are grooved to
support and carry the pistons. The joint between the flanges and the cylinder
ends is packed, and the pistons have upon their ends legs which are carried in the
grooves, and which project beyond the body of the pistons. To the ends of these
legs are attached slides which travel on an outer ledge nearly concentric with the
bore of the cylinder, and which assist in keeping the pistons in steam-tight contact
with the cylinder bore. Outside the flanges of the revolving drum are fixed covers
secured to the cylinder, completely enclosing all the working parts, and being also
constructed to carry the bearings of the engine shaft. This high pressure ordinary
piston engine is secured to a bed plate which also carries the rotary one, and the
shafts of the two engines can be either separate and the power taken off each
separately, or the shafts may be coupled together and the power of both trans-
mitted through the one shaft. The object of this Invention is to combine the
advantages of a low pressure rotary engine, that is, one whose piston or pistons
rotate round its shaft, with those of a high pressure reciprocating engine, whose
piston or pistons move in straight lines, so as to secure the maximum of economy
in the use of steam, and the minimum of space for an engine of given power.
Hitherto, all high pressure rotary engines have been unsuccessful in consequence of
the number of joints to be packed, and the great difficulty in keeping them tight
against high pressures. This difficulty is entirely removed when low pressures are
used, as the springs necessary to pack the joints can easily be made to overcome
the low pressure where they would be rendered quite useless against steam of high
pressure. Another advantage of the combination is the great steadiness of motion
given to the engine by the uniform pressure exerted upon the pistons of the rotary
engine, which in itself constitutes a most effective fly-wheel for the reciprocating
engine, without the weight and loss of power which is unavoidable with large fly
wheels, besides the space occupied. Fig. 1 is a longitudinal section through the
compound engine; Fig. 2 is a transverse section through the low pressure engine, and

page_text: Fig. 3 is a plan. Steam is admitted at a high pressure in the cylinder A of the
reciprocating engine upon the piston B, and transmits its force through the piston
rod C and connecting rod D upon the crank pin E of the shaft F, which it causes to
rotate when the piston B has arrived at the bottom of its stroke; the valve G
having previously cut off the supply of steam now opens the interior of the cylinder
above the piston to exhaust, and the steam which has been slightly expanded
passes through the valve G into the receiver H, and thence through the pipe I into
the rotary engine K. There it acts upon the several pistons of the engine in
succession, causing them to rotate round the shaft L. In the position of the
reversing valve V, as shown, all the ports are closed to the entrance and exit of
steam; upon shifting the valve to the left by means of the reversing lever R, the
low pressure steam flows through the port M direct upon the right hand side of
the piston N at the top, and the left hand side being open to exhaust, viz., to
the atmosphere or condenser, it is caused to move in the direction of the arrow.
When the piston passes the left hand port M the steam escapes from between
the pistons, and the following piston receives in its turn the full pressure of steam
upon its right hand side. Although in the Drawings but one kind each of rotary
and reciprocating engines are shewn, the Invention is not limited to, these two
kinds, but to all forms of rotary and reciprocating engines, and this particular
rotary engine is shown only because it is believed to be the best form of rotary
engine yet made. Also, in the Drawings the two engines forming the component
parts of the compound engine are shewn attached to separate shafts, the one a
hollow, and the other a solid shaft passing through the former, and this is a
form of the engine which is suitable for driving dual screws and propellers,
disintegrators, &c. And to keep the two engines revolving at the same speed
small bevel gearing or frictional gearing can be used, or various other methods
employed, such as a governor to each engine regulated for the same speed, and
controlling the throttle valves of the two engines, pulleys, and belts, &c.
Having thus described the nature and object of my said Invention, I declare
that what I claim and desire to be secured to me by the hereinbefore in part
recited Letters Patent is,-
1st. The combination of the high pressure reciprocating engine with the low
pressure rotary engine producing a new compound reciprocating rotary engine,
substantially as hereinbefore described and shewn on Drawings or any mere
modification thereof.
2nd. The combination of the above two engines with separate shafts, one hollow
and the other a solid shaft passing through the former, substantially as hereinbefore
described and shewn on Drawings or any mere modification thereof.
In witness whereof, I, the said Charles Spruyt de Bay, have hereunto set my
hand and seal, this Twenty second day of January, A.D. One thousand eight
hundred and eighty.
Witnessed the signature of
Charles Spruyt de Bay,
H. M. SYDNEY,
Solicitor,
53, Promenade des Anglais,
Nice,
France.
C. SPRUYT DE BAY. (L.S.)