Improvements in Air and Like Compressors.
Year: 1899

page_text: Date of Application, 15th Apr., 1899-Accepted, 30th Sept., 1899
2
Improvements in Air and Like Compressors.
We, JAMES ADAMS CHARTER, of Franklin and Monroe Streets, Chicago, Illinois,
and FRANKLIN GATFIELD HOBART, of the City of Beloit, Wisconsin, (address c/o
Works of Fairbanks, Morse & Co., Beloit, Wisconsin), both of the United States
of America, Mechanical Engineers, 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:-
This invention relates to that form of compressor which comprises essentially
a power and compression cylinder mounted upon opposite ends of a common
frame or bed, and having a crank shaft between such cylinders.
The first of the objects of this invention is the provision of a compressor of
the type specified, which will be simple and economical in construction, positive
and reliable in its operation, and more compactly arranged than most of the
compressors of like kind now in common use.
In order to acomplish the above object, there is provided a bed or frame
having a power cylinder mounted upon one end and a compression cylinder
mounted upon the other end thereof, and a crank shaft carried by bearing blocks
arranged intermediate said cylinders. Within the power cylinder, is arranged
a trunk piston of considerable length, one end of which projects out of such
cylinder in the direction of the compression cylinder, and is supported by guide-
ways, as and for a purpose which will hereinafter be more particularly described.
Between the power and compression cylinder is provided a yoke and rod
connection having opposite rods arranged on opposite sides of the crank shaft so
that the strain or force transmitted from one cylinder to the other will be carried
along a straight line, and not produce any side stresses, such as would result in
uneven wear of the cylinders and pistons.
In order to secure as compact an arrangement of the parts as possible, the two
cylinders are placed but a short distance apart, and in the inwardly projecting
end of the compression cylinder is provided an arrangement of slots which form
clearance ways for the yoke, and permit the full length of stroke required, while
at the same time affording an efficient guide for the compressing piston.
.i
The second part of this invention relates to that part of the apparatus which
is designed for the purpose of controlling or regulating the amount of pressure
delivered to and held within the fluid compressor receiver or reservoir, an
apparatus to which the term "unloading device" is not infrequently applied.
Heretofore it has been quite common to construct mechanism in which, when
the desired pressure in the reservoir was reached, an unloading or escape valve
from the compressor was opened by the operation of the pressure in the receiver
exerted against a diaphragm or piston, the diaphragm or piston being the moving
force which opened and closed the unloading valve. Such an arrangement has been
found to be objectionable, for the reason, first, that if a piston is employed,
leakage is almost sure to result, whereas if a diaphragm be used but little
range of movement is available, and the satisfactory-operation of the unloading

page_text: pression controller or unloading valve applied thereto;
Fig. 5 is an enlarged view, in section, showing the slow seating check valve;
Fig. 6 is a plan view of part of the mechanism of Fig. 4;
Fig. 7 is a partial elevation of some of the parts shown in Fig. 4, but on a
larger scale;
Figure 8 shows a portion of a compressor cylinder having the improved valves
applied thereto;
Fig. 9 is a section through an inlet and discharge valve;
Fig. 10 shows a detail of the guide used for the inlet valve stem;
In the practice of this invention there is provided, first, a bed or frame, 1,
upon one end of which is mounted a power cylinder (in this case a gas engine
cylinder) 2, and upon the other end of which is mounted a compression cylinder 3.
Between the two cylinders are bearing blocks or journals, 4, which carry the
crank shaft, 5. In order to support the projecting end of the power piston, 6,
and take the weight off the cylinder so as to prevent uneven wear of the latter,
there is provided a pair of guideways, 7, arranged as shown in Fig. 2, these
guideways carrying a combined cross-head and yoke casting, 8, attached to the
piston. Within the compression cylinder is a piston, 9, to the projecting end of
which is secured another yoke casting, 10, and within the inwardly projecting
extension of the compression cylinder are formed a pair of slots, 11, arranged
so as to make a clearance way for the yoke, and permit the latter to move past
the end of the cylinder, these provisions all permitting a full length of stroke
with a comparatively short length of the machine as a whole. As will be clearly
seen from an examination of Figs. 2 and 3, the rod or yoke connections, 12, are
arranged in a plane at an angle about halfway between the vertical and horizontal,
so as to pass one above and the other below the crank shaft, and yet transmit the
strains and power from one piston to the other in a direct line without any side
strain or bending moment, such as would result in an uneven wear of the
cylinders and pistons, as well as a certain loss in the percentage of power.
This improvement may be used on compressors actuated by hydrocarbon or
explosive engine cylinders, and it is in connection with such power cylinder
that the same has been illustrated and described herein, but it is not desired to
limit the claims on this feature to this particular class of power apparatus, as it
is obvious that the advantages of this improvement are applicable also to com-
pressors operated by other motive fluids.
Referring now more particularly to Fig. 4, it will be seen that in the connec-
tion leading from the compression cylinder, 3, to the receiver, 13, there is intro-
duced a check valve, 14, and between the check valve and the compression
cylinder there is a connection, 15, leading to an unloading or escape valve, 16,
the outlet, 17, of which goes to the atmosphere.
The valve, 16, is bolted to the frame of the compressor, and adjacent thereto
is an automatic pressure operated device, 18, having its pressure inlet connected
with the receiver by means of a pipe, 19. The plug, 20, of the valve, 16, (see
Fig. 7) is secured to a handle, 21, which is provided with a double set of
ratchet teeth, 22, 23, pointing in opposite directions. Mounted above these teeth
is a double ratchet pawl, 24, pivoted upon the outer end of a rocking lever, 25,
and arranged so that the reciprocating movement imparted to it through the
rod, 26, and the eccentric pin, 27, will tend to rotate the plug, 20, so as to open
or close the unloading valve according to which of the two sets of ratchet teeth
is engaged by the pawl, 24. This is determined by the amount of pressure in the
receiver acting against the diaphragm, 28, and lever, 29, in opposition to the
spring, 30, the upper end of the lever, 29, being connected to a rocker arm, 31,
the movement of which is transmitted to the pawl through the spring, 32, and
the link, 33, (see Fig. 6). By suitable adjusting devices the tension of the
open
spring, 30, can be set at any point desired, so that the unloading valve will
at any predetermined pressure in the receiver.

page_text: with the stem, and which is threaded to engage the spring retaining nut, 48.
The enlargement is designed to prevent the valve from dropping out in case the
spring-bearing nut should work off, and the nut is used in combination with the
enlargement because if the enlargement were made in itself of sufficient size
to form a bearing for the spring it would be more difficult to put the spring in
position. Surrounding the stem, 46, is a guide bushing, 49, which is made in two
parts, divided along a middle plane, as clearly shown in Fig. 10, so that they may
be put around the stem in spite of the enlargement, 47.
To facilitate the handling of these parts, not only in putting them in place,
but also in drilling and machining them when they are first made, there is
provided a containing collar, 50, made to fit snugly over the two split portions
of the guide bushing, 49, when the latter are in place on the stem, 46.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is:-
1. An improvement in compressors comprising a bed or frame, a power cylinder
mounted upon one end thereof, a compression cylinder mounted upon the other
end, a power piston having one end projecting out of said power cylinder, and
guideways carrying the projecting end of said piston.
2. An improvement in compressors comprising a bed or frame, a power cylinder
mounted upon one end thereof, a compression cylinder mounted upon the other
end, a power piston operating within said power cylinder, a compression piston
operating within said compression cylinder, a crank shaft mounted between said
cylinders, and a yoke and rod connection between said pistons, opposite rods
being arranged on opposite sides of said shaft and also on opposite sides of said
crank.
3. An improvement in compressors comprising the combination with a bed or
frame, a power cylinder and a compression cylinder mounted thereon, a power
piston and a compression piston operating in said cylinders, and a yoke connec-
tion between said pistons, of slots in the inwardly projecting end of said com-
pression cylinder, said slots forming clearance or guideways for said yoke.
4. The combination with a compressor having an unloading valve applied
thereto, of a check valve between said unloading valve and the compressor
receiver, said check valve being provided with means whereby its seating is
retarded.
5. A compressor unloading device or controller comprising an unloading
valve, means whereby said valve may be opened and closed by motion received
from some moving part of the compressor, and means whereby said first men-
tioned means is thrown into or out of action automatically by the pressure in the
receiver.
G. A compressor unloading device comprising a check valve, a ratchet handle
secured thereto, a pawl designed to engage said ratchet handle, connection between
said pawl and some moving part of the compressor whereby said pawl receives a
reciprocating motion, and an automatic pressure operated device whereby said
pawl is thrown into or out of action to open or close said unloading valve.
7. A compressor unloading device comprising a check valve, a ratchet handle
secured thereto, a pawl designed to engage said ratchet handle, connection
between said pawl and some moving part of the compressor whereby said
pawl receives a reciprocating motion, and a spring and diaphragm device whereby
said pawl thrown into or out of action to open or close said unloading valve.
8. A compressor unloading device comprising a check valve, a ratchet handle
secured thereto, a pawl designed to engage said ratchet handle, an eccentric pin
rotated by the compressor whereby said pawl receives a reciprocating motion,
and an automatic pressure operated device whereby said pawl is thrown into or out
of action to open or close said unloading valye.
9. A compressor valve having a stem provided upon its spring end with an