IMPROVEMENTS IN THE CONSTRUCTION AND PACKING OF SLIDE VALVES AND ADJACENT PARTS FOR STEAM AND OTHER ENGINES.
Year: 1867

page_text: LETTERS PATENT to Norman Willis Wheeler, of the City of Brooklyn, in
the County of Kings, in the State of New York, in the United States
of America,, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION
AND
PACKING OF SLIDE VALVES AND ADJACENT PARTS FOR STEAM AND OTHER
ENGINES.".
COMPLETE SPECIFICATION filed. by the said Norman Willis Wheeler
at the Office of the Commissioners of Patents; with his Petition and
Declaration, on the 7th May 1867, pursuant to the 9th Section of the
Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, NORMAN
WILLIS WHEELER, of the City of Brooklyn, in the County of Kings: in the
State of New York, in the United States of America, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
THE CONSTRUCTION AND PACKING OF SLIDE VALVES AND ADJACENT PARTS FOR
STEAM AND OTHER ENGINES," and have petitioned Her Majesty to grant unto
me. my executors, administrators, and assigns, Her Royal Letters Patent
for the same, and have made solemn Declaration that I am the true and first-
Inventor thereof.
NOW KNOW' YE, that I, the said Norman Willis Wheeler, do hereby
déclare that the following Complete Specification, under my hand and seal; fully
[Price $d.]

page_text: the same is to be performed, in and by the following statement, reference
-being-had to the accompanying Drawings, with letters of reference_marked
thereon, forming a part of this Specification, in which Figure 1 is a longi-
tudinal section of a part of a steam chest. fitted with a half piston or valve;
Figure 2 is a cross section of the same; Figure 3 represents a steam chest
fitted with a piston valve, the left half being, a longitudinal section, the right
half a side elevation; Figure 4 is a cross section of the same on line T, T, in
Figure 3 Figure 5 is an end elevation of the steam chest. the left half
having the cover on, the right half the cover off; Figure 6 is a longitudinal
section on line S, S, Figure 4. representing an additional detail, which may
be used and which forms a part of my Invention. Similar letters of reference
indicate like parts in the several Figures.
Piston slide valves have been considered by theorists the best valves known
for steam engines: they probably would be so were it not for the difficulty of
mechanically adjusting the packing rings to meet the peculiar requirements of
their functions. In all examples that have come to my knowledge the packing
rings have been "set" or compressed against the sides of the valve cylinder
by springs or other means by a constant energy. Now when the valve
covers only a part of a port which is taking steam. so much of the surface of
the piston as is not covered by the surface of the valve cylinder is pressed
inwards by the action of the steam, and if the springs be not so strong as to
cause a great amount of friction the ring must yield to such pressure and
allow steam to pass the valve into the exhaust chamber. This difficulty has
instigated the trial, in many partially successful instances, of methods of
setting the rings by rigid mechanical arrangements. whereby the valves while
in use were in effect solid and unyielding pistons or discs, and only adjustable
while less hot than when in use, and not capable of accommodating themselves
gradually to the gradual wear of the parts.
In the examples before us a is the steam cylinder; b, b, the steam ports;
c, the exhaust. way; d. d, the valve rod; e, e, the piston valves; f, f, the
packing rings thereof; i, i, i, small ports leading from the exposed valve faces
into the space within the rings i, j, the live steam passages g, the valve
cylinder which is seen in Figures 1 and 2 as a semi-cylinder 1. 1. When the
engine is in motion the valves e, e, have a reciprocating motion longitudinally
with their axes over and across the ports b. b, and when either valve is
delivering steam to the engine steam passes into the corresponding port and
presses the rings inward; or in the example Figures 1 and 2 presses the valve
up against the semi-cylinder 1, 1, but at the same time steam passes into the

page_text: spaces . o. inside the rings and neutralizes the aforesaid pressure. When
the exhaust takes place the valve is in such position. see the left in Figure 3,
that the steam flows out of the ports i. i, and relieves the internal pressure at
the same time that the external pressure is relieved, so that if the valve
pistons be fitted with ring springs or the rings fit the valve cylinder by their
own clasticity, in the same manner as is usual for working pistons. the rings
will have for all the time not requisite for the lap of the ports i. i, the effective
pressure only of the springs against the sides of the valve cylinder, and will
accommodate themselves in the varying expansions and wear of the valve
cylinders in a more perfect manner than analogous devices have hitherto been
made to do.
In Figures and 2 the valves having a solid face and being backed with
packing rings the rings are made in halves or such parts of a circle that their
ends may fit fair upon the valve face. the semi-rings. being riveted together
near the ends and the cuts distributed properly around the semi-circle. In
the construction and use of piston valves, especially in the case of these which
are provided with periodical steam packing behind or inside the rings.
experience has shown that the bridges across the port for the cuts of the rings
to traverse are necessary, and that it is difficult to bore the valve barrels truly
cylindrical if the ports are made in the barrel before it is bored; and, further.
that the aberrations occur chiefly upon the surfaces of the bridges. Of course
if the barrels are not truc the valve rings will not fit tightly in all positions.
and there will occur a loss by leakage, and the friction will be increased. For
the sake of truthful work I bore out the chamber to fit a tapered bush g'.
which bush is in turn fitted by turning and scraping or grinding to the
chamber and secured tightly by the half-and-half threaded set. bolts p, p; the
bush is then easily bored true, and the ports cut afterwards, leaving the bridges
true with the other parts of the barrel; and the work is greatly facilitated for
the reason that the bush may be treated separately and no hand holes or caps
to allow access at the proper points to cut the ports are necessary, as would be
the case if the barrels were in one piece with the chamber.
Figure 6 shows an attachment which is useful in some cases, for instance,
when it is not desirable to construct the engine with a crank attachment. g²
represents a small cylinder in one with the cap of the valve chamber, into
which is fitted a corresponding piston attached to the end of the valve rod,
and so proportioned that the steam port for the small cylinder will be covered
by the piston as it approaches the end of its throw, so as to imprison the steam
beyond it and form a steam cushion to arrest the movement at the proper
point. At the opposite end of the valve chamber is fixed a corresponding

page_text: piston and cylinder. The steam passages b' lead from the steam passages b
between the valve and the working cylinder. Now when the valve is thrown
by means of a tappet or otherwise so far that steam will enter the working
cylinder_through_one_of_the_passages-the-release-will-have-taken-place-through-
the other, and the 'sicam' pressure upon the respective small pistons will be
equal to that in the respective ends of the working cylinder by reason of the
communications through the small passages b', and the overbalancing pressure
upon one of the small pistons will complete the throw beyond that made by
the tappet or other device, which tappet or device must compress or cause the
partial expulsion of the steam in one of the cylinders opposing its action until
the release takes place.
Having described my Invention I will proceed to state what I consider
new and useful, and for which I desire to secure Letters Patent, viz.
First, claim the bushing constructed and arranged substantially as
represented relatively to the valve e and the ports b for the purpose set
forth.
Second. I claim in combination with the engine the within-described
construction and arrangement of the ports ii. packing ring or rings /.
expanded substantially as herein set-forth:
In witness whereof I have hereunto set my hand and seal, this "Third
day of April. A.D. 1867.