Lubrication Means for Cyclically Discharging Lubricant Into a Fluid Working Chamber

This invention pertains to lubricating means for machinery, and in particular to lubricating means having especial utility in a positive displacement machine, such as an air compressor, or engine, in which the piston operates in cycles to define repetitive compressed gas volumes.

It is an object of this invention to set forth, in a machine such as a gas compressor, gas expander, engine, pump, or the like, having a piston movably disposed within a chamber in which at least a first portion of said chamber defines an inlet area for admitting thereinto a fluid having the properties of a given velocity, a given volume, and a given pressure, and a second portion of said chamber defines a fluid-working area in which such admitted fluid has at least one of the properties thereof altered by interaction of surfaces of said chamber and said movable piston, means for lubricating said surfaces, comprising first means for providing a source of lubricant under pressure; a device having means comprising a repository for confining therein a volume of lubricant conducted thereto, and having means, operative in response to fluid under pressure addressed thereto, for moving lubricant from said repository to a lubricant-discharging location in said device; one conduit means, communicating said first means and said repository, for conducting lubricant to said repository; another conduit means, communicating one of said areas with said lubricant-moving means, for conducting pressured fluid from said one area and addressing the same to said latter means to effect operation thereof; and a further conduit means, communicating the other of said areas with said lubricant-discharging location, for conducting lubricant from said latter location into said other area for lubricating said surfaces.

It is another object of this invention to disclose, in a machine, such as a gas compressor, gas expander, engine, pump, or the like, having a piston, disposed within a chamber, for cyclic movement thereof within said chamber, in which at least a first portion of said chamber defines an inlet area for cyclically admitting thereinto a fluid having a given pressure, and a second portion of said chamber defines a fluid-working area in which such admitted fluid has the pressure thereof varied by cyclically repetitive interaction of surfaces of said chamber and said movable piston, means for lubricating said surfaces, in timed, cyclically repetitive sequences related to cyclic movement of said piston, comprising first means for providing a source of lubricant under pressure; a device having means comprising a repository for confining therein a volume of lubricant conducted thereto, and having means repetitively operative, in response to fluid under varying pressure repetitively addressed thereto, for moving lubricant from said repository to a lubricant-discharging location in said device; one conduit means, communicating said first means and said repository, for conducting lubricant to said repository; another conduit means, communicating said second portion of said chamber with said lubricant-moving means, for repetitively conducting varying-pressured fluid, cyclically, from said second portion and addressing such varying-pressure fluid to said latter means to effect a corresponding cyclic operation thereof; and a further conduit means, communicating said first portion of said chamber with said lubricant-discharging location, for conducting lubricant, cyclically, from said latter location into said first portion for lubricating said surfaces.

Yet, another object of this invention comprises, for retrofitting thereof to a machine, such as a gas compressor, gas expander, engine, pump, or the like, having a piston disposed within a chamber for cyclic movement thereof within said chamber, in which at least a first portion of said chamber defines an inlet area for cyclically admitting thereinto a fluid under a given pressure, and a second portion of said chamber defines a fluid-working area in which such admitted fluid has the pressure thereof varied by cyclically repetitive interaction of surfaces of said chamber and said movable piston, means for lubricating said surfaces in timed, cyclically repetitive sequences to cyclic movement of said piston, comprising a device having means comprising a repository for confining therewithin a volume of lubricant conducted thereto, and having means repetitively operative, in response to fluid under varying pressure repetitively addressed thereto, for moving lubricant from said repository to a lubricant-discharging location in said device; means for conducting lubricant under pressure, from a source thereof, to said repository; first conduit means communicating with said lubricant-moving means for conducting fluid under pressure thereto to effect operation thereof; said first conduit means having means for coupling thereof in fluid communication with said second piston of said chamber for conducting cyclically, repetitively varying pressure fluid from said second portion of said chamber to said lubricant-moving means; and second conduit means communicating with said lubricant-discharging location in said device for conducting lubricant therefrom; wherein said second conduit means has means for coupling thereof in fluid communication with said first portion of said chamber for conducting lubricant into said first portion for lubrication of said surfaces.

Further objects of this invention, as well as the novel features thereof, will become more apparent by reference to the following description taken in conjunction with the accompanying figures, in which:

FIG. 1 is a combination schematic and pictorial illustration of an embodiment of the invention in use with a rotary compressor;

FIG. 2 is a cross-sectional view of the lubricator valve employed in the embodiment of FIG. 1, the same being shown along the longitudinal axis thereof;

FIGS. 3, 4, 5, and 6 are sequential illustrations showing the rotor of FIG. 1 in successive, rotary dispositions within the machine; and

FIG. 7 is a combination pictorial and schematic illustration of an alternative embodiment of the invention, the same being shown in use with a reciprocating compressor.

As shown in the figures, a rotary compressor 10, having a three-lobed rotor 12, comprises a housing 14 which defines a chamber 16 in which the rotor describes a rotary, epicyclic motion. During the rotation, the rotor 12 cooperates with the housing 14 to define a chamber inlet portion 18, a compression portion 20, and an expansion portion 22. The housing 14 has coupled thereto an oil sump 24 and the compressor 10 is coupled to an ancillary device 26. The latter is provided for use in injecting minute portions of lubricant into the chamber 16 for the purpose of lubricating the surfaces of the rotor 12 and the walls of the chamber 16. Device 26 is a valve coupled to the compressor 10, first by an air pressure line 28 which communicates between a fitting 30, which is in traverse a wall of the housing 14, and opens onto compression portion 20 at the one end, and line 28 opens into the valve device 26 at the other end thereof. Another fitting 32 also in traverse of the wall of the housing 14 opens onto the inlet portion 18 of the compressor 10 and is also joined, through a lubrication injection line 34, to the valve device 26. An oil pump 35, driven by the compressor 10, by means of a lubrication supply line 36 is also coupled to the valve device 26. Finally, there is a lubrication return line 38 coupled to the valve device 26 and to the sump 24.

In FIG. 2 the device 26 is shown, in greater detail, to be a piston-operated valve 40 which comprises a valve body 42 having a central channel 44 formed therein in which a stem 46 is slidably disposed. The stem 46 is substantially of a uniform diameter excepting for an intermediate portion 48 thereof having a reduced diameter. Portion 48 is normally disposed within a repository 50 formed between, and joining, an inlet oil port 52 (hidden, as it opens into the valve 40 from the rear thereof, as viewed in FIG. 2), and an outlet oil port 54 (which opens onto the front of the valve 40). The channel 44 opens onto a larger passageway 56 which further communicates with a cylinder 58 in which a piston 60 is reciprocably disposed. A compression spring 62 biases the piston 60 to the right, as viewed in FIG. 2. Inlet and outlet compressed air ports 64 and 66, respectively, open into the valve body 42, on opposite (upper and lower) sides thereof, to communicate with an oil-discharging void or area 68 within the body.

With the rotor 12 cycling within the chamber 16 the piston 60 is caused to retract and transfer oil, which is confined within the repository 50 to the oil-discharging area 68. Here, the oil will be ejected by the compressed air, and conducted, through the lubrication injection line 34, to the inlet portion 18 of the compressor 10.

The sequence of events can be appreciated by reference to FIGS. 3 through 6 in turn. Considering the lobes "A", "B", and "C" it can be seen that, in FIG. 3, lobe "A" is so disposed in the chamber 16 that the rotor 12 has not yet closed off the inlet 70 to the compressor 10. The arrows shown in the illustration represent the lubrication injection line fitting 32 and the air pressure line fitting 30. In FIG. 4 lobe "A" of the rotor 12 is commencing to occlude the inlet 70 of the compressor 10, and in FIG. 5 it has completely closed off the inlet 70. Accordingly, the volume of fluid (air) within the chamber 16 between lobes "A" and "B" will proceed to diminish and be pressurized. As a consequence, the portion of such compressing fluid, which is tapped off via fitting 30 and line 28, will enter port 64 and passageway 56. This will cause the piston 60 to retract and carry oil, on portion 48 of the stem 46, from the repository 50 to the oil-discharging area 68 in the valve. The rotor 12 continues to rotate, and the compression portion 20 of the chamber 16 greatly reduces in volume. The compressed air product proceeds to exit via the discharge port 71. The resulting increasing air pressure in line 28, port 64 and area 68 blows the oil off the stem portion 48 and passes it through the port 66 and the lubrication injection line 34 to the fitting 32 from whence the oil is expelled into the inlet portion 18 of the compressor 10. In FIG. 6, the rotor 12 has moved on to a further positioning in which lobe "A" has passed by the fitting 30. Now then, fittings 30 and 32 and ports 64 and 66 share a common ambient or inlet pressure; as a consequence the spring 62 returns the piston 60 to the normal (FIG. 2) disposition. The reduced or intermediate stem portion 48 returns to interpositioning, between the inlet oil port 52 and the outlet oil port 54, in the repository 50, to pick up another charge of lubricant. It will be understood, then, that each time the rotor 12 describes a one hundred and twenty degree rotation a new charge of oil is injected into the compressor 10.

While the invention has particular utility in rotary machines, it is also applicable to reciprocating machines, and FIG. 7 illustrates an embodiment thereof so employed. In this, the same valve 40 and pump 35 are employed, but here the machine is a reciprocating air compressor 72, in which the piston 74 travels from a first positioning 76, which corresponds to its top dead center, to a second positioning 78, corresponding to the piston's bottom dead center. Compressor 72 has the conventional inlet and discharge valves 80 and 82 mounted atop the cylinder 84, and they function in the conventional manner. A minute aperature 86 is formed in the top of the cylinder 84 to receive a fitting to accommodate the air pressure line 28 (FIG. 1). However, to admit the lubricant into the cylinder 84 for lubrication three (only two are visible) minute holes 88, for ejection fittings 32 (FIG. 1), are formed through the wall of the cylinder 84 intermediate the first and second positionings 76 and 78 of the piston 74. In the same manner as explained in connection with the embodiment of FIG. 1, the reciprocation of the piston 74 in the cylinder 84 will cause the fluid (air) pressure to inject oil into the cylinder. The oil will pass from the valve 40 and through the lubricating injection line 34 into the three holes 88 in the cylinder 84 to lubricate the walls of the cylinder and the outer surfaces of the piston 74.

Machines, i.e., gas compressors, engines, expanders, and the like, of course, can be originally fabricated with the instant invention incorporated therewith. Alternatively, the invention can be retrofitted to existing machines. Such is simply accomplished by providing the valve device 26, lines 28, 34, 36 and 38, and fittings 30 and 32, and (a) setting the fittings in traverse of the machine housing, and (b) coupling the lines to the fittings, the machine sump 24, and pump 35, as shown in FIG. 1 (or FIG. 7).

While I have described my invention in connection with specific embodiments thereof, it is to be clearly understood that this is done only by way of example, and not as a limitation to the scope of my invention, as set forth in the objects thereof and in the appended claims.