Improvements in Valves for Blowing Engines.
Year: 1896

page_text: Date of Application, 1st Dec., 1896-Accepted, 23rd Jan., 1897
COMPLETE SPECIFICATION.
[Communicated from abroad by JULIAN KENNEDY, of Pittsburg, in the County
of Allegheny, State of Pennsylvania, one of the United States of America,
Mechanical Engineer.]
Improvements in Valves for Blowing Engines.
I WILLIAM BURGELAND JOHNSON of 4 Clayton Square, Liverpool in the
County of Lancaster, Engineer, 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, reference being had to the
accompanying drawings forming part of this specification in which :-
Figure 1 is a vertical longitudinal section of a blowing engine cylinder provided
with my improved valve system.
Fig. 2 is an end elevation of the piston head showing one of the valves in cross-
section.
Fig. 3 is a top plan view of the cylinder and
Fig. 4 is a view similar to Fig. 1, showing a modification.
My invention relates to the valves employed in pneumatic cylinders-such as
blowing engines, air compressors, refrigerating apparatus, etc. and is designed to do
away with the disadvantages consequent to the use of the present type of valves.
In blowing machinery where the valves are of the gridiron type, they are
unbalanced and considerable power is necessary to move them. As they must be
moved quickly and with intermittent motions, severe shocks, and strains are set up
in the valve gear. In former valves of the piston type, in which the above named
disadvantages are not present, a large amount of clearance was necessary in the
operating cylinder. These evils are entirely done away with by my invention.
In the drawings, in which like numerals indicate like parts, 2 represents a
blowing cylinder, having therein the piston 3, whose piston-rods 4 are actuated by
a suitable motive cylinder. Through the head of the piston 3 pass two tubular
valves 5 and 6, which are open at both ends and are surrounded by suitable
packing rings, as shown, where they pass through the piston and the cylinder-
heads. Each valve is reciprocated independently of the piston by means of the
valve-stems 7, which in turn may be actuated by eccentrics or by other mechanism.
There are also near to its ends annular bridged ports 8, 9, 10, and 11, the ports 8
and 9 being in the inlet valve 5, while the ports 10 and 11 are located in the outlet
valve 6. The outlet valve 6 is considerably longer than the inlet valve, and its
ends are cased in by projecting end pockets 12, which communicate with the
common offtake 13 leading to the reservoir.
14 are tubular stays for the valve casings or pockets.
arrow,
The action is as follows:-As the piston moves upward in the direction of the
it is forcing air through ports 10 into the valve 6, and therethrough into
the reservoir. At the same time it is drawing in air upon the other side through
the open ends of the valve 5 and the ports 9. As the piston nears the end of its
stroke, the valve 5 is moved down and the valve 6 is moved up, and as it reaches
the end of its stroke, the valve 5 reaches its mid-position and both ports 8 and 9
are shut off, while the valve 6 has moved up to such point as to close the outlet-
port 10. As the piston begins to move down, the valve 5 is also moved down and
air enters behind the piston through the port 8. The outlet valve, however being
longer and thus provided with inside lap, has not yet reached the point where the

page_text: ports 11 communicate with the interior of the cylinder, and hence the piston
compresses the air in the cylinder to or about the pressure of the reservoir before
the ports 11 come within the cylinder, upon which air passes from the cylinder into
the valve and from both ends thereof to the reservoir. As the piston nears the end
of its down stroke, the valves are moved, valve 5 up, and valve 6 down, closing
both the inlet and outlet ports at or about the instant when the piston has reached
the end of its stroke, and when the piston again reaches its mid-stroke the cycle of
movements again begins.
Instead of the reciprocatory tubular valves 5 and 6, I may employ stationary
valve casings 15 and 16 as shown in Fig. 4 over which the piston head reciprocates
and within which move the valves 18 which are adjustably secured to the valve
stems 17. These valve-casings are provided within the cylinder with annular
bridged ports 19, and the valves are actuated in a similar manner to those above
described, the operation being substantially similar. I prefer however, the form
of Fig. 1, because all clearance in the cylinder is thereby done away with.
The advantages of my invention will be apparent to those skilled in the art,
since the piston acts to the very end of its stroke, there being no clearance on
account of the movement of the tubular valve. The valves are balanced in all
positions and move smoothly and uniformly with no pounding and require little
power to be exerted thereon, while all their movements are positive and not
dependent either upon the air or upon weights or springs.
The reciprocatory valve-tubes might be closed at the ends, and many other
changes may be made without departing from my invention, since I consider myself
the first to provide a valve which passes through the piston and cylinder-heads, the
word "valve "being used in its broad sense whether consisting of a movable tube
as in Fig. 1 or a stationary tube and inner moving port, as in Fig. 4, as well as the
first to employ the tubular valve in the combination recited in my last claim.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
First. A cylinder having a moving piston or plunger-head, a valve extending
through the piston head and through the cylinder heads and means independent of
the piston for actuating the valve; substantially as described.
Second. A cylinder having a piston or plunger head, and tubular inlet and outlet
valves extending through said piston-head; substantially as described.
Third. A cylinder having a piston or plunger head, tubular inlet and outlet
valves extending through said piston-head, and ineans for reciprocating said valves;
substantially as described.
Fourth. A cylinder having a piston or plunger-head, tubular valves having ports
in their sides and extending through the piston-head, and means for reciprocating
said valves independently of the piston-head; substantially as described.
Fifth. A cylinder having a piston or plunger-bead, tubular inlet and outlet
valves extending through said piston head, and means for reciprocating said valves,
the outlet valve being arranged to open after the piston has moved a part of its
stroke; substantially as described.
Sixth. A cylinder having a piston or plunger head, and tubular inlet and outlet
valves extending through the piston head and through the cylinder heads;
substantially as described.
Seventh. In a punip or compressor system, a cylinder provided with a moving
piston, a tubular valve arranged to reciprocate through the cylinder head, and
having side ports, and means for moving the valve so that its ports shall be
alternately placed inside and outside said head; substantially as described.
Dated this 30th day of November 1896
W. B. JOHNSON.