Airline lubricator

An airline lubricator in which a diaphragm is disposed in a closed annular chamber surrounding an axial air passage to divide the chamber into an air pressure chamber and a lubricant reservoir. The air pressure chamber is coupled by an angulated pressure tube to the primary air passage adjacent the lubricator inlet. A metering tube and adjustable screw arrangement at the output of the reservoir control the amount of lubricant fed to the primary air passage as a function pressure drop across the primary air path. A ball-type check valve including an adjustable valve seat is disposed across the primary air path in opposition to the metering tube for preventing passage of lubricant in the absence of primary air flow.

The present invention is directed to airline lubricators, and more 
particularly to a device for automatically injecting lubricant into a 
compressed airline fed to a pneumatic tool or the like. 
A general object of the present invention is to provide an airline 
lubricator of simple construction which is economical to manufacture and 
which provides reliable service over an extended operating lifetime. 
A more specific object of the invention is to provide an airline lubricator 
of the described type which is adapted to be coupled to an airline in any 
desired orientation, and which feeds lubricant to the airline only when 
air is flowing therein. 
Yet another object of the invention is to provide an airline lubricator of 
the described type wherein the amount of lubricant fed to the airline may 
be readily adjusted.

The drawings illustrate a presently preferred embodiment 10 of an airline 
lubricator in accordance with the invention as comprising an enclosure or 
casing 12 including a hollow cylindrical tube or pipe 14 defining a 
central air passage 16 of uniform diameter extending along the tube axis. 
An inlet head 18 is integral with tube 14 at one end thereof, and includes 
a tapered internally threaded opening 20 aligned with passage 16 for 
defining an air inlet. An outlet head 22 is threaded onto the opposing end 
of tube 14 and includes an internally threaded tapered opening 24 aligned 
with passage 16 for defining an air outlet. An airline may be connected to 
openings 20,24 using suitable fittings (not shown). 
A cylindrical sleeve or casing wall 26 is captured between heads 18,22 and 
cooperates therewith to define an annular chamber 28 coaxially surrounding 
air passage tube 14 intermediate the air passage ends. An annular 
diaphragm 30 of resilient elastomeric oil-resistant construction has a 
circumferentially continuous bead 32 at one end captured in sealing 
compression by wall 26 against a radially facing shoulder 34 on head 18. A 
second circumferentially continuous bead 36 at the opposing end of 
diaphragm 30 is elastically received in tension over tube 14 adjacent head 
22. In its relaxed state (not shown in the drawings), diaphragm 30 extends 
from beam 32 along the inner surfaces of wall 26 and head 22, and along 
tube 14 to bead 36. Thus, diaphragm 30 effectively divides annular chamber 
28 into an annular air pressure chamber 38 adjacent inlet head 18 and an 
annular oil reservoir 40 adjacent outlet head 22. 
An air pressure tube 42 extends at an angle through tube 14 at the juncture 
of the latter with inlet head 18. The end 44 of tube 42 within air passage 
16 is disposed at about the axis thereof and is cut or formed at an angle 
so as to be oriented in a radial plane facing in the direction of inlet 
opening 20. Thus, tube 42 feeds inlet air pressure to chamber 38. An 
annular resilient O-ring 46 is sealingly captured in compression by wall 
26 against a radially facing shoulder 48 on head 22. A lubricant passage 
50 extends within head 22 from reservoir 40 parallel to the axis of air 
passage 16. A metering tube 51 is press-fitted into head 22 and extends in 
the radial direction from the reservoir-remote end of passage 50 into air 
passage 16, terminating adjacent the air passage central axis. A set screw 
52 is threaded into head 22 in axial alignment with tube 51 and has an 
insert 53 at the inner end thereof which cooperates with the opposing 
radially outer flat end of tube 51 for varying the effective opening size 
of the metering tube input end, and thereby varying the amount of 
lubricant fed to air passage 16 for a given drop in pressure through air 
passage 16. 
A check valve 54 is carried by head 22 for preventing flow of lubricant 
from metering tube 51 into passage 16 in the absence of air flow in the 
latter. Check valve 54 comprises a head 55 threadably received in 
enclosure head 22, and a hollow sleeve or shank 56 extending integrally 
and coaxially therefrom in diametrically opposed alignment with metering 
tube 51. A coil spring 58 is carried internally of sleeve 56 and biases a 
valve element ball 60 against the opposing flat end of metering tube 51. 
As best seen in FIG. 4, ball 60 is disposed at about the central axis of 
air passage 16. The outside diameter of ball 60 is less than the inside 
diameter of sleeve 56. A ring 63 surrounds sleeve 56 and engages the 
opposing threads in head 22 for holding head 55 in desired set position. 
FIG. 3 illustrates the reservoir fill mechanism as comprising a fill 
passage 62 extending within head 22 axially and then radially from 
reservoir 40. A screw 64 closes the reservoir-remote end of passage 62. A 
ball 66 is captured by a retaining clip 68 within passage 62 adjacent 
reservoir 40 to prevent back-flow of lubricant under pressure to screw 64. 
In operation, in the absence of air flow in passage 16, metering tube 51 is 
closed by valve ball 60 and passage of lubricant to the airline is blocked 
in all orientations of lubricator 10. As air flow begins within passage 
16, an increase in air pressure with chamber 38 urges lubricant from 
within reservoir 40 through passage 50 and tube 51 against ball 60. When 
lubricant pressure is sufficient to overcome spring 58, ball 60 will be 
urged away from metering tube 51 and lubricant will be aspirated into the 
flowing air. Transparent wall 26 permits observation of lubricant 
reservoir 40, which may be refilled through passage 62 (FIG. 3) when 
empty. It will be appreciated that screw 52 and head 55 are accessible 
from externally of enclosure 12 and may be readily adjusted during 
operation of the lubricator. Likewise, ball valve 66 permits removal of 
screw 64 and filling of the reservoir without shutting down the airline 
and/or removing lubricator 10 therefrom. Screw 52 adjusts the amount of 
lubricant fed to metering tube 51 as a function of air pressure, and head 
55 adjusts the effective spring pressure on valve ball 60.