IMPROVEMENTS IN STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to James Vivian, of Mylor Bridge, in the County of Corn-
wall, for the Invention of "IMPROVEMENTS IN STEAM ENGINES."
Sealed the 22nd September 1877, and dated the 28th March 1877.
PROVISIONAL SPECIFICATION left by the said James Vivian at the Office
of the Commissioners of Patents on the 28th March 1877.
"
JAMES VIVIAN, of Mylor Bridge, in the County of Cornwall. IMPROVEMENTS
IN STEAM ENGINES."
This Invention consists of improvements in steam engines, which I designato as
"D engines," same being specially applicable for direct-acting pumps.
These improvements are mainly as follows:-Instead of the circular or round
piston employed in steam engines I substitute a semicircular or D piston, and I
dispense with the ordinary piston and connecting rods. Within the semicircular or
D piston is a guide into which a block is fitted, same being free to slide, the block
also being fitted on the crank pin. Thus, by this arrangement, instead of attaching
a slotted cross head to the piston rod, as is the case in some direct-acting donkey
pumps, I combine the piston and cross head together; and therefore, instead of the
ordinary slotted cross head to carry the slide block on the crank pin, I fit within
the D piston the guide which serves the same purpose, and the D piston serves as
the ordinary piston would in the usual arrrangement; and thus I have the cross
head, the slide block, and crank, all within the piston, the shaft passing through the
valve box cover and other parts.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Vivian in the Great Seal Patent Office on the 28th September
1877.
#
JAMES VIVIAN, of Mylor Bridge, in the County of Cornwall.
IN STEAM ENGINES."
"IMPROVEMENTS
This Invention consists of improvements in steam engines, which I designate as
D engines," same being specially applicable for direct-acting pumps.
These improvements are substantially as follows:-Instead of the circular or
round piston employed in steam engines, I substitute a semicircular or D piston,
and I dispense with the ordinary piston and connecting rods. Within the semi-
circular or D piston is a guide, into which a block is fitted, same being free to slido,
the block also being fitted on the crank pin. Thus, by this arrangement, instead of
attaching a slotted cross head to the piston rod, as is the case in some direct-acting
donkey pumps, I combine the piston and cross head together; and therefore, instead
of the ordinary slotted cross head to carry the slide block on the crank pin, I fit
within the D piston the guide which serves the same purpose, and the D piston
serves as the ordinary piston would in the usual arrangement; and thus I have the
cross head, the slide block, and crank, all within the piston, the shaft passing through
the valve box cover and other parts.
Having thus far described the nature of the said Invention, and incidentally
intimated in what manner the same is to be performed or carried out in practice, I
will now proceed (aided by the accompanying Drawings) to further and particularly
describe and ascertain in what manner the same is to be performed or carried out in
nuention that is to save
Fig. 1 represents a side elevation of my improved engine; Fig. 2 is sectional
clevation, the piston being at half stroke; Fig. 3, transverse section, the piston
being at half stroke; Fig. 4, clevation of guide and piston.
In these Figures A represents the shaft mounted in bearings A¹, said bearings
being secured to the framing A2 of the machine; B is the fly or driving wheel on
shaft A; C is the piston, of semicircular or "D" form, working in case D, in which
caso D the valve D¹ is inserted, saine being worked by shaft A. and eccentric in the
usual way; E, slido block working within piston C, said block E being attached by
crank pin and crank F to the shaft A; G, slide, fitted on to slide block E, and con-
tained within the piston C; H, guide attached to the piston C; I, packing ring.
The piston C is kept in position by india-rubber packing K, as shown in Fig. 3. The
shaft A and guide H work through stuffing boxes, as shown. It will be seen that
by these arrangements, as shown in the Drawings, the shaft A actuates the valve D¹
by means of an eccentric in the usual way, admitting steam through the ports to
the piston C, and driving same round, said piston having within it the slide block
E and slide G, the block being provided with the crank F and crank pin secured to
driving shaft A, on which is fixed the driving wheel B, as shown. The improve-
ments, as above described and illustrated, are applicable for direct-acting pumps,
and for propelling boats, and so forth.
Having now particularly described and ascertained the nature and object of the
said Invention and in what manner the same is to be performed or carried out in
practice, I hereby declare that I claim the Invention of "Improvements in Steam
Engines," substantially as shown by the accompanying Drawings, and herein
described; particular and important points in such Invention being that, instead of
attaching a slotted cross head to the piston rod, as is the case in some direct-acting
donkey pumps, the piston and cross head are combined together; and therefore,
instead of the ordinary slotted cross head to carry the slide block on the crank pin,
within the D piston a guide is fitted which serves the same purpose, and the

page_text: D piston serves as the ordinary piston would in the usual arrangement, and thus the
cross head, the slide block, and crank are all within the piston, the shaft passing
through the valve box cover and other parts.
In witness whereof, I, the said James Vivian, have hereunto set my hand and
seal, this Twenty-sixth day of September, in the year of our Lord One
thousand eight hundred and seventy-seven,
Witness,
Wm. OATES,
Mylor Bridge,
Cornwall.
JAMES VIVIAN. (L.S.)