AN IMPROVED EXPANSION GEAR FOR STEAM ENGINES
Year: 1876

page_text: LETTERS PATENT to Carl Pieper, of Dresden, 'Saxony, for the Invention of
"AN IMPROVED EXPANSION GEAR FOR STEAM ENGINES."
from Carl Joseph Cario, residing at Nienburg, Prussia.
A communication
PROVISIONAL SPECIFICATION left by the said Carl Pieper at the Office of
the Commissioners of Patents on the 24th February 1876.
CARL PIEPER, of Dresden, Saxony. "AN IMPROVED EXPANSION GEAR FOR
STEAM ENGINES." A communication from Carl Joseph Cario, residing at Nienburg,
Prussia.
The object of my Invention is to cause an automatic adjustment of expansion
valves in steam engines by means of the governor, and especially in those expansion
valves which consist of two parts sliding on the back of the distributing valve, and
which cut the steam off at an earlier or later period of the stroke, according as the
distance between the two parts is increased or decreased. Adjustment of the
expansion valve may be effected by some kind of hand gear, or it may be caused
automatically by the governor of the engine. All the arrangements, however,
hitherto designed for the latter purpose, either do not fulfil their object at all or
they require so much power from the governor that the same not only becomes very
insensitive but also quite uncertain in its action as soon as it may have to overcome
any accidental increase of resistance, the consequence being that the adjustment of
the expansion valve is incomplete and defective. These imperfections it is the
intention of my improved automatic expansion gear to obviate, and by the same to
ensure a certain and accurate action of the steam engine governor on the expansion
valve, so as constantly to keep the same duly adjusted for the mean velocity of the
engine. For this purpose I, by preference, adopt the following arrangements :-I
attach to each expansion valve part a separate rod passing through a stuffing box
of the valve chest. Outside of the latter these rods are by preference made
rectangular, between them lies a third rectangular rod jointed to and forming part
of the rod of the expansion eccentric. On a bolt passing through this centre rod.a
lever turns, the pins at either end of which project into vertical slots of the two
horizontal valve rods, so that the centre rod being kept stationary and the lever
being turned, the two expansion valve parts will be equally moved in opposite
directions, thereby altering their distance from each other without affecting the
D

page_text: distance between the centre of the entire valve and the eccentric. To the lever a
sector of a circle is attached, on which an adjustable break acts for causing sufficient
friction, so as to prevent any undesired alteration of the relative position of the
valve rods; each of these (the one on the right, the other on the left hand side)
bears two tappets, which strike against two vertically moveable inclined bars or
ledges, the distance between the tappets on either rod being such that they just
touch the corresponding ledges at the end of the stroke; the said ledges are suitably
attached to the governor, and moved vertically up or down by the same in proper
guides. As soon as the position of the inclined ledges is altered one of the tappets
will strike on one of the same sooner than before, but the eccentric continuing on
its course will either draw or push the centre bar onward, the lever consequently
turning on that one of its pins as a fulcrum, which is in relation to the rod
arrested by its tappet; the pin at the other end will shift the corresponding rod in
the direction in which the centre rod works, but it will shift it double the amount
of its own motion from the moment the tappet struck the inclined ledge; the two
valve parts will therefore be shifted further apart or closer together, as the case may
be, and the point of cut-off will be altered accordingly.
The said inclined ledges
are at liberty to move up and down by the action of the governor, and have not
themselves to operate the shifting of the slides; they only give the measure for the
shifting, which is then carried out by the full power transmitted through the eccentric.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Carl Pieper in the Great Seal Patent Office on the 24th August
1876.
CARL PIEPER, of Dresden, Kingdom of Saxony. "AN IMPROVED EXPANSION
GEAR FOR STEAM ENGINES." A communication from Carl Joseph Cario, of Nienburg-
on-the-Saale, Prussia.
The object of this Invention is to cause an automatic adjustment. of expansion
valves in steam engines by means of the governor, and especially of those expansion
valves which consist of two parts sliding on the back of the distributing valve, and
which cut the steam off at an earlier or later period of the stroke, according as the
distance between the two parts is increased or decreased. The adjustment of the
expansion valve may be effected by some kind of hand gear, or it may be caused
automatically by the governor of the engine. All the arrangements, however,
hitherto designed for the latter purpose, either do not fulfil their object at all or
they require so much power from the governor that the same not only becomes very
insensitive but also quite uncertain in its action, as soon as it may have to overcome
any accidental increase of resistance, the consequence being that the adjustment of
the expansion valve is incomplete and defective. All these imperfections are
obviated by the improved automatic expansion gear, as the same ensures a perfectly
certain and accurate action of the steam engine governor on the expansion valve, so
as constantly to keep the same duly adjusted for the mean velocity of the engine.
For this purpose to each expansion valve part a separate rod is attached passing
through a stuffing box of the valve chest. Outside of the latter these rods are by
preference made rectangular; between them lies a third rectangular rod jointed to
and forming part of the rod of the expansion excentric. On a bolt passing through
this centre rod a lever turns, the pins at either end of which project into vertical
slots of the two horizontal valve rods, so that the centre rod being kept stationary
and the lever being turned, the two expansion valve parts will be equally moved in
opposite directions, thereby altering their distance from each other without affecting
the distance between the centre of the entire valve and the excentric. To the lever
a sector of a circle is attached, on which an adjustable break acts for causing
sufficient friction, so as to prevent any undesired alteration of the relative position
of the valve rods; each of these (the one on the right, the other on the left hand

page_text: side) bears two tappets, which strike against two vertically moveable inclined bars
or ledges, the distance between the tappets on cither rod being such that they just
touch the corresponding ledges at the end of the stroke; the said ledges are suitably
attached to the governor, and moved vertically up or down by the same in proper
guides. As soon as the position of the inclined ledges is altered one of the tappets
will strike on one of these ledges sooner than before, but the excentric continuing on
its course will either draw or push the centre bar onward, the lever consequently
turning on that one of its pins as a fulcrum, which is in relation to the rod
arrested by its tappet; the pin at the other end will shift the corresponding rod in
the direction in which the centre rod works, but it will shift it double the amount
of its own motion from the moment the tappet struck the inclined ledge; the
two valve parts will therefore be shifted further apart or closer together, as the
case may be, and the point of cut-off will be altered accordingly. The said inclined
ledges are at liberty to move up and down by the action of the governor, and
have not themselves to operate the shifting of the slides; they only give the measure
for the shifting, which is then carried out by the full power transmitted through the
excentric.
This arrangement is represented on the annexed Sheet of Drawings in Figures 1
to 4. A and A¹ are the two parts of the expansion valve, to which are attached
the rods B and B¹; outside of the valve chest these are provided with the slotted
lugs C and C¹, through which pass the pins at the ends of the double lever D, D¹,
the arms of the latter being equal. This lever turns by a bolt E in a bearing at
the end of the rod F, which is jointed to the excentric rod, or which forms part
of the same.
As long as the lever D, D¹, is retained in its relative position
to the rod F, the valve rods B and B¹ have to partake of the motion of the
excentric rod; but if one of the valve rods strikes with one of the lateral
tappets, G, G¹, or H, H¹, on any fixed point before having finished its course, the
lever D, D, will turn, and the rods B and B will be shifted with respect to each
other, so as either to increase or to decrease the distance between the valve parts.
The piece I embraces the three rods B, B¹, and F, and an adjustable wedge K serves
to press the same against the sectors L and L attached to the double lever D, D', so
as to cause friction between the two; this piece I consequently acts as a brake to
prevent the lever and the valve rods from altering their relative position by any
accidental cause, and the wedge K has to be so adjusted that the friction between
the brake block I and the sectors L, L', is just sufficient for the stated purpose,
without causing an undue resistance against the desired shifting of the valve parts;
this friction, however, need but slightly to exceed the greatest possible difference
between the frictional resistance of the one valve part with its rod and that of the
other. The fixed points alluded to above, against which the tappets of the valve
rods strike, are given by the two inclined bars or ledges M and M¹.
These are
attached to the inside of a suitable sliding frame T, T, moved vertically up and
down by the sliding collar of the governor, as shown by Fig. 4. In Fig 1 these
inclined ledges are nearly in their lowest position, so that the valve parts are close
together. Supposing now the governor to rise by an increase of speed, the ledge M
will be raised and (the rod F moving to the left) tappet H meets the ledge sooner
than before, consequently the rod B is arrested, but rod F moving onward over-
comes the friction between L, L, and I, and shifts the rod B₁ and valve part A¹ in
the same direction forward, for double the amount of that part of its own course
travelled through from the moment in which tappet H met the ledge M to the end
of the stroke, and the consequence is that the valve part A¹ will close the left-hand
steam port of the distributing valve sooner than before. The effect of the rising
of the governor is consequently such as to cause an carlier cut-off of the steam for
the same stroke of the engine, and as will be perceived from the whole design the
alteration in the relative position of the valve parts is carried out quickly. If the
excentric rod with the rod F moves in the direction opposite to that supposed
before, the tappet G₁ will now meet the inclined ledge M sooner than before, so as
thereby to be arrested, the effect on the valve being only in so far different as the

page_text: slide part A is now advanced to the right, so as to cause the earlier cut-off by this
port, through which the steam is entering at the monent. The governor descending,
either one of the tappets G or H₁ comes into action, so as to shift the valve parts
closer together.
The amount of inclination of the ledges M and M¹ is to be equal to the greatest
difference in the distance of each valve part from the centre line of the entire valve.
In case a great nicety and correctness of regulation is desired these ledges should
have a curved shape, as the relation between the variations in the rise of the
governor and the variations of the engine power, from an alteration in the
expansion, are not to be expressed by a simple mathematical proportion, but in
general it will be preferred to make the ledges straight.
As has been stated the tappets should just touch the corresponding inclined
ledges at the ends of the stroke, to adjust them properly so as to fulfil this
condition a wedge N has been arranged acting on the bearing of the bolt E; by
this wedge and the other one K, the relative position of the rod F to the rods B
and B may be slightly altered, so as to make up for any minor inaccuracy of
workmanship. The ledges M and M being inclined the tappets will cause a certain
angular pressure on the same, which will even affect the governor in case the angle
of inclination is smaller than the angle of friction between tappets and ledges. In
general this angle should be larger, but in case it is desired to give a short lift to
the governor the ledges may be made rough, or they may be provided with
horizontal furrows, the tappets being fitted with a sharp edge corresponding to the
furrows; these sharp edges may be made in separate picces out of steel, which are
then to be hardened and fastened to the tappets.
For sake of facility in the manufacture it is prefered to make the valve rods out
of two parts, and to join them together by a cotter. The part passing through the
stuffing box is of course to be round, whilst the other part should be of rectangular
section, as also the rod F; this shape allows of placing the rods close together
and of letting them work in one guide. The part O designed for this purpose is
conveniently cast together with the standard of the governor, and as is shown in
the Drawing it may at the same time serve for guiding the rod of the main steam
valve and also the frame T.
If the governor is driven by a strap, as supposed in the Drawing, the engine is in
danger of assuming an exceedingly high velocity; in case this strap breaks, or if
it falls off from the pulleys, as the governor stopping in consequence, would allow
the ledges M and M₁ to assume their lowest position, and to adjust the expansion
valve to the greatest possible admission of steam. To prevent the danger which
might arise from such an occurrence, two projections Q and Q have been fixed
inside of the frame T; these correspond to the lower ends of the ledges M and M¹
and act in the same manner as these, so that the frame T dropping down altogether
the valve will be adjusted to the shortest admission of steam; if the governor is
driven by tooth wheels this arrangement may be dispensed with. On the sector La
scale may be engraved, on which a fixed pointer (represented in the Drawing as a
projection on the wedge K) shows at every moment the amount of steam admitted.
In the engine fitted with the gear of the Drawing this admission varies from 0·052
to 0.949 of the stroke.
'
The shape and arrangement of the inclines M and M₁ may be modified in various
ways; each of the valve rods, for instance, may have but one tappet, which moves
between the inclined ledges of two wedge shaped plates united at the ends, so
as to form a hollow parallelogram, as shown by Figures 5 and 6; of these wedge
pieces the one may be left away, so that the adjustment of the valves is effected
but once at every revolution, and this arrrangement shown by Figures 7 & 8 may
be considered preferable for engines running at a high speed.
In the Figures alluded to the wedge plates have moreover been arranged so as
to move horizontally in front of the valve rods' ends, the tappets being thereby
dispensed with; in this case the ends of the said plates have to be placed square,
one above the other; but these single wedges may also be arranged vertically, or

page_text: the double wedges horizontally; and, finally, in all these constructions the valve
rods may be placed at the sides of the excentric rod, instead of being above and
below the same.
The principle of the described arrangement for regulating steam engines by
altering the degree of expansion may however be applied with similar advantages
for regulating the speed of other motors.
良
The modification of the Invention shown in the Figures 9 to 12 serves for
regulating the speed of turbines and water wheels, as well as of steam engines in
general, and of other prime motors, by acting on a sluice valve, a throttle valve, &c.,
or on any expansion gear whatever. The levers D, D¹, and the first arrangement
have been designed in the present modification as full discs D, D', on which the two
brake blocks I and I act from opposite sides; these blocks, of which Fig. 12 is an
end view, also serve for guiding the rods B and B¹. The oscillations of the
discs D, D¹, are transmitted by a connecting rod N to a sluice valve, or to other
parts which regulate the introduction of the dynamic medium. The rod F has to
receive a reciprocating motion from an excentric, or from any other suitable part of
the motor. The rods B and B' upon arriving at the end of their stroke should just
touch the double wedge M, whilst the latter remains stationary, but as soon as the
wedge rises or descends, according to the action of the governor to which it is
connected, the two rods B and B are shifted with regard to each other; but instead
of utilizing this effect directly, as with the expansion valves, the angular motion of
the discs D, D¹, resulting from the relative shifting of the rods B and B¹, is trans-
mitted by the connecting rod N to a sluice valve, &c., in the manner as stated
above. The block P at the end of the rod F moves between the guides Q, which
also serve as support for the double wedge M to bear against whilst the rods B or B¹
press on it; laterally the wedge is guided by a slot in the rod F, through which it
passes. If an adjustment of the rods B and B¹ is required at both ends of their
stroke, a second double wedge has to be arranged, which acts on the other end of
the rods. Moreover, the arrangement of the wedges may be modified in a similar
manner, as has been described with regard to the designs of the Figures 5 to S.
The Figures 13 to 15 represent this Invention applied to a steam engine with
reversing gear. In this case two pairs of wedges are wanted, the one pair M, M¹,
for the forward, the other pair M³, M³, for the backward motion; the upper
wedges M and M² are in one piece, as also the lower ones M1 and M³ (see Fig. 15)
and both pieces are connected together by stays. The wedges act on the double
lever D, D, which is held in its position by the friction caused by the brake plates I
acting laterally on the rib K of the aforesaid lever; the arm L of this lever carries
the sector block of the sector G, G¹. The combined wedges are adjusted for forward
or reverse motion according as the bar P is hooked either with the notch n or the
notch on the stud m of the wedges; whilst this is being carried out by hand,
the resistance caused by the weight of the balls of course has to be overcome.
one pair of wedges causes the lever L to stand in any position above the center
line E, E, and to descend to within this line, according as the governor rises, and
the other pair makes the lever L assume a position below the said line and to rise
with the rising of the governor, but within the same limit; the entire lift of the
governor corresponds to the length of either pair of wedges. The wedges are hung
to the tops of the swinging rods 0, 0, and they bear at the back against the frame
of the governor.
The advantages of the described regulating gear are the following:-
The
1. It causes no resistance to the governor; the action of the latter is therefore
solely dependent on the influence of the engine.
2. The alteration in the position of the governor only give the first cause and the
measure for the shifting of the parts, by which the regulation is to be effected,
whilst the shifting itself is carried out in conformity with this measure by the full
power of the motor, and consequently with absolute certainty and accuracy.
3 According to the shape which is given to the ledges M and M¹ (in the case of
expanding steam engines) the amount of alteration in the degree of expansion for

page_text: different points of cut-off may be different for equal variations in the position of
the governor balls, i. e., the increase or decrease of admission of steam at different
grades of expansion may be any desired mathematical function of the rise of the
governor. Taking into account that for a given amount of relative shifting of the
valve parts the alteration of the engine power is greater at a low grade of admission
of steam than at a higher one, the stated property gives the means for compensating
the undue influence of this circunstance on the final effect of the governor, in case
a great nicety of regulation is required.
4. In expansion steam engines the adjustment of the valve parts (Fig. 1-4)
according to the position of the governor balls is not carried out gradually, but on
the contrary suddenly, and before the closing of the steam port; consequently, the
smallest as well as the greatest deviation from the mean speed is immediately
counteracted in a corresponding degree, so that an increase of such deviation (which
may easily arise from an incomplete or a retarded correction) can never take place,
the number of revolutions which the engine makes remaining almost exactly
the same.
With regard to turbines the effect of my apparatus is similar.
5. The entire regulating gear for steam engines is placed outside of the valve
box, it is therefore easy of access, and no parts are exposed to set fast from
heat.
6. The described gear for steam engines is the single automatical one in existence;
which not only allows a perfectly free play of the governor but also a variation in
the admission of steam, from zero to the full contents of the cylinder.
7. The arrangement is simple, it does not contain any parts uncertain in their
action, and it is not liable to any material wear.
Having now particularly described and ascertained the nature and object of the
said Invention, and in what manner the same may be performed or put in practice,
I hereby declare that I claim the herin described Invention, wherein the following
are important points or features:—
1. The inclined, either straight or otherwise shaped bars or ledges M. and M³,
Figures 1-4, or their equivalents, such as wedge picces, &c., in combination with
a steam engine governor, and acting on the two rods of an expansion valve, as and
for the purpose set forth.
2. The projections Q and Q¹ of Figures 1-4, in combination with the aforesaid
bars or ledges M and M', as described.
3. The lever or levers D and D¹, Figures 1-4, combined with the two valve
rods B and B and the excentric rod F, as stated in the foregoing.
4. The brake block or blocks I, Figures 1-4, acting on the sector or sectors L
and L¹, or any equivalent of these parts, in combination with the valve rods B
and B and the excentric rod F, as and for the purpose described.
5. The double wedge M, Figures 9 & 10, the two rods B and B¹, one or two
dises D, D¹, the brake block or blocks I, I¹, and the rod F, or the equivalents of
these pieces combined together, and with the governor, as and for the purpose
specified.
6. The two pairs of wedges M, M³, and M2, M3, Figures 13-15, the lever D, D, L,
the brake plates I, or any equivalents of these pieces combined together and with the
governor of a steam engine, as described, and for the purpose stated.
In witness whereof, I, the said Carl Pieper, have hereunto set my hand and
seal, this Thirteenth day of July, in the year of our Lord One thousand
cight hundred and seventy-six.
CARL PIEPER. (L.S.)