Exhaust and Equilibrium Valves and their Gearing.
Year: 1888

page_text: Exhaust and Equilibrium Valves and their Gearing.
I, OTTO ERNEST POHL of 48 Regent Road, Liverpool in the County of Lancaster,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
-
Hitherto the cylinders of steam engines have been made, as a rule, of cast iron and
the valve boxes, jackets, passages etcetera are cast on. The object of this invention is,
to avoid the difficulties arising from this method through uncertain turn out of
material (flaws, ruptures) uneven expansion of parts, great waste of time and money,
in the moulding, casting, and boring, and the limit in length of cylinders, owing to
the certainty of breakage by expansion, through heat; also great weight of engine.
To accomplish this object, I employ steel tubes of any desired length, welded or
drawn, and shove each end into a hollow cast block of metal containing the steam
exhaust (and the equilibrium passages if used). The blocks have bolt-holes for
fastening them to the framework. A steam tight connection between the cylinder and
the blocks can be effected in three ways, namely,
1. By a stuffing box, the gland of which is made to fit the hollow of the block, stud
bolts, fast in the block, holding the lid of the gland, pressing against the packing
between cylinder and block.
2. The cylinder fits the hollow of the block, and on the inner side of the hollow a
groove is left and filled with lead or other metal, or other suitable material of greater
expanding power, than the cylinder or block material; on the heating through steam
taking place, the lead (or other material) ring in the groove, grasps the cylinder
tightly, and permits no escape of steam, though expansion of the cylinder may
take place lengthwise, a space being provided therefor in the block.
3. In case of short cylinders, a flange fastened on the cylinder may be joined to
Each block has a
the block, which may be without hollow in that case.
passage
for the incoming and another for the exhaust steam, and if a steam cushion is
desirable, it has a third passage for the equilibrium valve; each passage communicates
between the cylinder and the outside. The outsides of the passages may be shaped in
1011

page_text: the casting at once as valve faces, or these can be put on after. I use slide valves in
preference; but others may be employed likewise. The valves are arranged so that
one steam and one exhaust on the opposite block of the cylinder are joined in a
suitable manner and connected to moving gear, be it excentrics, cams, or other
means.
The exhaust valve is set so as to open earlier than the steam valve in order that the
steam of the one side of the piston may escape before fresh supply enters on the other
side. The exhaust valve may be pressed against its face by springs or other means,
if the face is direct unto the exhaust opening of the block. but a way far preferable to
this is to let the steam itself do the pressing work, by laying the face of the exhaust
valve on the lid of the box and letting the cylinder steam press on the top instead of
the bottom of the valve. In order to provide a steam cushion for the piston at the
end of the stroke, so called equilibrium valves communicate with each end of the
cylinder, through the third passages in the blocks, and at the same time each valve
communicates with another pipe, screwed into the cylinder not far from the end;
the distance from the end must be long enough to allow the piston to go over the
opening of this pipe, when the valve being opened simultaneously the steam on the
one side of the piston goes to the other side of the same, producing equilibrium, and
forms at the same time a steam cushion for the piston. These two valves are connected
by gearing and worked in such a way that one shutting, the other one opens. The
equilibrium valves, can be arranged in either of two ways:
1. A square box with two parallel partition plates, forming three compartments the
partition plates having each a slot, one above the other, the slide moving between the
plates by a rod through a stuffing box, shutting or opening the slots, so that steam
may enter and leave both ways. Each of the outer compartments has steam pipes
joined to it.
2. A box with one horizontal partition containing two slots, being shut by the
slide alternately and letting steam pass during the movement of the slide both
steam pipes entering the second chamber which is divided by a vertical partition.
My system applies to rotative engines, and to reciprocating ones as well.
For slide valves a new mode of motion has been invented, (for the reciprocating
engine preferably). Two cylinders are required which form the engine, or if one only
is intended as chief worker, an auxiliary one becomes necessary. The two cylinders
being laid or erected parallel at a distance from one another on a plate, a pillar is
fastened to this plate in the centre of that square, two sides of which are formed by
the two piston rods, when at full stroke out of the cylinder. On this pillar two swinging
levers are arranged one above the other with telescopic motion from the piston rod
ends or crossheads. Parallel to the outstretched piston rods, bars are so fixed on the
plate, that the levers (which may also be forkshaped) sweep over or under them; the
bars have holes in them into which tappets, hung on bolts in framework, are shoved
by those levers, effecting a throw, on the one stroke of a certain distance, and on the
return stroke the levers pass over them, without moving said tappets, or if they do so,
the tappets are arranged in such a manner, as to give way and not work. They are
hung eccentrically in the frame, so as to have one end heavier than the other one,
which makes them fall back to their first position, after having been removed on the
back stroke. To increase the difference of weight of the two ends of the tappet,
mercury or lead may be put in bore holes. The tappets pushed for the certain
distance, required for the valve stroke, move the framework which is fast by a rod to
a lever, connected to the valve rod. Through this gear it becomes possible to cut off
the steam at any part of the stroke in the same valve box, which admits the steam into
the cylinder. One can arrange the movement of the cylinder in opposite directions or
very nearly simultaneously, use the tappets at the top or bottom of the holed bars and
introduce many varieties.
For the one cylinder the crosshead is required to cut off the steam when the tappets
are standing with the tappet points facing each other, upper side sloping, lower side
horizontal in the case of the opening tappet, upper, side horizontal, lower side sloping
in the case of the shutting tappet. It is evident that if the tappets stand in the reverse

page_text: way, namely, points facing opposite ways, but lower sides horizontal in each case, one
lever may work them; two tappets with their frames work one valve rod, the one
opening, the other shutting the valve, the one in doing so erecting always the other
one for the net-work.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or Appertaining to Steam Cylinders and Steam,
Exhaust and Equilibrium Valves and their Gearing.
I, OTTO ERNEST POHL of 4S Regent Road, Liverpool in the County of Lancaster,
Manufacturer, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
Hitherto the cylinders of steam engines have been made, as a rule, of cast iron, and
the valve boxes, jackets, passages, etcetera, are cast on. The object of this invention
is to avoid the difficulties arising from this method through uncertain turn out of
material (such as flaws or ruptures) through uneven expansion of parts, through great
waste of time and money in the moulding, casting, and boring, and through the
limited length of the cylinders, owing to the certainty of breakage by expansion
through heat; also the great weight of the engine is another difficulty.
Referring to the accompanying drawings
-
Figures 1 and 2 show, in end elevation and longitudinal section respectively, one
way of securing the ends of the cylinders to the cylinder blocks.
Figures 3 and 4 are similar views showing a modified way of securing the
cylinders to the blocks.
Figures 5 and 6 show, in transverse section and central section respectively,
cylinder block with its passages and valve boxes.
the
Figures 7 and 8 are sectional plans of the steam and exhaust valves respectively
with their boxes.
Figures 9, 10, and 11, show, in front sectional elevation, side sectional elevation,
and sectional plan respectively, one form of equilibrium valve and box.
Figures 12, 13 and 14, show, in side sectional elevation, front sectional elevation,
and sectional plan, respectively, another form of the above valve and box

page_text: Figures 15, 16, and 17, show in front elevation, side elevation, and plan respec-
tively, one way in which the invention may be applied to a rotative engine.
Figure 18 shows a detail of the valve gear for said engine.
Figure 19 is a plan of a pair of horizontal reciprocating engines as constructed
in accordance with my invention.
Figure 2 is a longitudinal sectional elevation of the starboard engine.
Figures 21 and 22 are transverse sections of the starboard and port engines,
respectively.
Figure 23 is an enlarged view of the tappet gear for working the valves.
Figures 24 and 25 illustrate the working of the valves of the port and star-
board engines respectively.
To accomplish the object above mentioned, I employ steel tubes 1 of any desired
length, welded or drawn, and shove each end into a hollow cast metal block 2, contain-
ing a steam passage 3, Figures 5 and 6, and exhaust passage 4, and an equilibrium
passage 5 (if equilibrium valves be used). The blocks have bolt-holes through which
bolts 6 may be passed for fastening them to the framework 7. A steamtight con-
nection between the cylinder and the blocks can be effected in three ways, namely:-
1. By a stuffing box, the gland 8 (Figures 1 and 2) of which is made to fit
the hollow S of the block 2, and by stud bolts Sb fast in the block, holding the
gland and pressing it against the packing between cylinder and block.
2. The cylinder fits the hollow 2 of the block, and on the inner side of the
hollow, a groove 9 (Figures 19 and 20) is left and filled with lead or other metal,
or other suitable material of greater expanding power, than the cylinder or block
material. On the heating through steam taking place, the lead ring (or ring of other
material) in the groove 9 grasps the cylinder tightly, and permits no escape of
steam, though expansion of the cylinder may take place lengthwise, a space 2
being provided therefor in the block.
3. In case of short cylinders, a flange 10 (Figures 3 and 4) fastened on the
cylinder, may be joined to the block, which may be without hollow in that case.
Each block has a passage 3 for the incoming, and another 4 for the exhaust steam.
If a steam cushion is desirable it has a third passage 5 for the equilibrium valve 5*
or 5, which passage communicates between the cylinder and the outside of the
block. The outer ends of the passages may be shaped in the casting at once as valve
faces, or these can be put on after. I use slide valves in preference, but other
forms may be employed likewise. The valves are arranged so that one steam
valve 3 and one exhaust valve 4" on the opposite block 2 of the cylinder, are joined
in a suitable manner and connected to moving gear 12, be it eccentrics 13, cams 14,
or other means.
The exhaust valve 4" is set so as to open earlier than the steam valve, in order that
the steam of the one side of the piston may escape before fresh supply enters on the
other side. The exhaust valve may be pressed against its face by springs or
other means if the face is direct unto the exhaust opening of the block, but a
way far preferable to this, is to let the steam itself do the pressing work by laying
the face 11 (Figures 5 and 6) of the exhaust valve on the lid of the box, and letting
the cylinder steam press on the top instead of the bottom of the valve. In order to
provide a steam cushion for the piston at the end of the stroke, so called equilibrium
valves 5ª or 5 communicate with each end of the cylinder, as in Figures 16 and 20,
through the small passages 5 in the blocks 2, and at the same time each valve com-
municates with another pipe 15 screwed into the cylinder not far from the end.
The distance of this pipe from the end of the cylinder must be long enough to
allow the piston 16 to go over the opening of this pipe, when, the valve being
opened simultaneously, the steam on the one side of the piston goes to the other side
of the same, producing equilibrium, and forming at the same time a steam cushion for
the piston. These two valves are connected by gearing 17, and worked in such a
way that on one shutting the other one opens. The equilibrium valves can be
arranged in either of two ways:-
1. A square box 18 (Figures 9, 10 and 11) with two parallel partition plates 18ª

page_text: forming three compartments, the partition plates having each a slot 18 one
above the other, the slide 5 moving between the plates by a rod 18 through a
stuffing box, shutting or opening the valve so that steam may enter and leave
both ways.
Each of the outer compartments has steam pipes 19 joined to it.
2. A box 20 (Figures 12, 13 and 14) with one horizontal partition. 20° con-
taining two slots 20 being shut by the slide 5 alternately, and letting steam pass
during the movement of the slide. Both steam pipes 20° enter the second chamber
which is divided by a vertical partition 20d.
My system or arrangement of valves applies to rotative engines as in Figures
15, 160, and 17, and to reciprocating ones as in Figures 19 to 22 as well.
For slide valves a new mode of motion has been invented (for the reciprocating
engine preferably). Two cylinders 1 (Figures 19 to 22) are required, which form
the engine, or if one only is intended as chief worker, an auxiliary one becomes
necessary. The two cylinders are laid or erected parallel to and at a distance from
one another on a plate 21, and a pillar 22 is fastened to this plate in the centre of
that square, two sides of which are formed by the two piston rods 23, when at full
stroke out of the cylinder. On this pillar two swinging levers 24 and 24* are
arranged one above the other, being connected by telescopic device to the piston rod
ends or to the cross heads 23ª and 23. Parallel to the outstretched piston rods, bars
or plates 25 are so fixed on the plate 21, that the levers 24 and 24" (which may also
be forkshaped if desired) sweep over or under them. The bars have holes 26
(Figures 19 and 23 to 25) in them, into which tappets 27 and 27, hung on bolts 28
in framework 29, are shoved by the levers 24 and 24ª as soon as they have effected a
throw of the framework on the one stroke of a certain distance. On the
return stroke, the levers 24 and 24" pass over the bars 25 without moving
said tappets 27 or 27ª, if they are in the position shown in dotted lines at 27,
or if they do move the tappets, the latter are arranged in such a manner, as to give
way and not work the framework 29, this may be seen from Figures 23 to 25: They
are hung eccentrically in the frames 29, so as to have one end heavier than the other
one, which makes them fall back to their first position, after having been removed on
the back stroke. To increase the difference of weight of the two ends of the
tappet, mercury or lead may be put in bore holes therein. Or springs may
be used to return the tappets to their proper position. The tappets pushed for the
certain distance required for the valve stroke, move the framework 29, which, is con-
nected by a rod 30 to a lever connected to the valve rod. Through this gear it
becomes possible to cut off the steam at any part of the stroke, with the same valve.
and valve box which admit the steam into the cylinder, as it is only necessary to
alter the positions of the tappets and that of the holes 26. One can arrange the
pistons to move in opposite directions or very nearly simultaneously, and the
tappets may be used at the top or bottom of the holed bars 25, and many varieties in
details may be introduced. The tappets may be struck by blocks sliding upon the
edges of the bars 25, the said blocks being provided with a pin which projects upwards
into a slot in the lever 24 or 24. This ensures the tappets being struck always in
the same straight line.
In one cylinder (the port cylinder in the drawings) the steam is cut off directly
by a projecting arm 23 on the crosshead 23°. In this case the tappets 27 are
arranged as in Figure 24, that is, with their points facing each other. In the
other cylinder the tappets are arranged as in Figure 25, with their points looking
away from each other.
17ª is the gear connecting a rod 30 with one steam and one exhaust valve, and 17b
is the gear connecting another rod 30 with the other steam and exhaust valves.
In the engine shown on the drawings, the valves and their gear are so arranged
that the pistons move almost abreast of each other. The starboard cylinder, how-
ever, receives its steam for a greater portion of the stroke than the port cylinder. As
a consequence of this, the lever 24 arrives at the end of its travel and takes up its
working position behind the steam tappet of the port cylinder, just before the arrival
of the port piston at the end of its stroke. During the remaining portion of the

page_text: stroke of the port piston it causes the lever 24" to be moved backwards to the full
extent of its travel so that it engages the starboard steam tappet and admits steam
to the starboard cylinder for the return stroke. The starboard piston thus receives an
impetus, in the reverse direction by the time the port piston has reached the end of
its stroke, and on the commencement of the return stroke of the starboard piston
the lever 24 strikes the port steam tappet, behind which it was momentarily
resting, and quickly admits steam into the port cylinder for the return stroke. It
will thus be seen that there is no likelihood of either of the pistons sticking at the
extreme ends of their strokes. The above arrangement may, of course, be reversed,.
the port engine taking the lead.
As, in the above arrangement, the starboard engine takes the lead and receives a
greater amount of steam than the port engine, it may be found desirable, in order to
ensure the opening and closing of the starboard equilibrium valves at the proper
moment, to work the latter valves, independently of the movement of the port piston,
by means of a separate lever. This lever may be pivoted at some convenient point in
such a manner that its lower end projects into the path of the crosshead 23, and its
upper end into that of the frame 29. The crosshead, as it approaches the end of
its stroke, strikes the lower end of the lever and causes the frame 29 to be moved
in the reverse direction, so as to open the equilibrium valve.
It will be seen from Figures 24 and 25 that two tappets with their frames are
employed to work one valve rod. The movement of the frames when operating the
valve rod in one direction, causes the inoperative tappet to be erected ready for work-
ing the rod on the return stroke of the lever.
In figures 15 to 18 inclusive, the invention is shown as applied to a rotative
engine. The valves, valve casings, &c., are similar to those already described, the
chief difference in the construction of the machine being that the valve rods 12 and 17
are actuated by means of the cam 14 or the eccentrics 13, instead of by tappets.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. A steam engine cylinder composed of a tube of drawn or welded steel, secured at
either end to a cast block, containing the necessary steam passages and valve boxes.
2. In a steam engine cylinder such as herein set forth under Claim 1, the combina-
tion with the steel tube and end blocks thereof, of a stuffing box surrounding each
end of said tube and secured to each of the said blocks, whereby steam tight con-
nection between the said tube and end blocks is obtained, substantially as set forth.
3. In a steam engine cylinder such as herein set forth under Claim 1, the combina-
tion with the steel tube and end blocks thereof of a ring of metal or other material
(having a greater rate of expansion than steel) surrounding said tube at each end, and
held within a groove in each of said blocks, whereby a steam tight connection between
the said tube and end blocks is obtained, substantially as described.
4. A steam engine having a cylinder composed, as herein described and. claimed, of
a steam tube and cast end blocks, and having the necessary cylinder valves located
within boxes in said blocks, and worked by suitable connecting rods, links or
. their equivalent outside the said cylinder, substantially as set forth.
5. In a steam engine having a cylinder such as herein described, an exhaust valve
working against a valve face on the valve chest cover with its back turned to the
steam contained in the cylinder, and connected by gear outside the cylinder and steam
passages in the air with the steam valve on the opposite end of the cylinder, substan-
tially as and for the purposes set forth.
6. In a steam engine and equilibrium valve consisting of a box divided into three
compartments by two parallel partitions, each of the outer compartments communica-
ting with a steam pipe, and each of the said partitions, being provided with an
opposing slot and having a sliding valve located between them, and working over said
slots, whereby the passage of the steam from one outer compartment to the other is
momentarily interrupted, substantially as described.

page_text: 7. In a steam engine, an equilibrium valve, consisting of a box divided into three
chambers by two partitions at right angles to each other, each of two of said chambers
communicating on the one hand with a steam pipe, and on the other hand by means
of a slot with the third of the said chambers, the latter chamber being provided with a
sliding valve which closes each of said slots alternately, and thereby momentarily
interrupts the passage of the steam, substantially as set forth.
S. A steam engine cylinder provided with two synchronously working equilibrium
valves, such as herein set forth in Claim 6, each of said valves, communicating on the
one hand with the extreme end of the said cylinder, and on the other hand with a
hole therein at a distance from the end of said cylinder slightly in excess of the depth
of its piston, whereby the steam in the cylinder, after serving for the work of the
stroke, is led to the opposite side of the piston and restores equilibrium in the cylinder,
and at the same time serves as a cushion to the piston, substantially as described.
9. In a steam engine, the means herein set forth, for actuating the valves and
regulating the cut off, namely, a series of counterweighted tappets hung eccentrically
in a framework and actuated from the piston rod, through the medium of a crosshead
and a telescopic lever, by being dropped into holes in one or more bars located below
them, substantially as set forth.