US1817698A

US1817698A - Unloading device

Info

Publication number: US1817698A
Application number: US363214A
Authority: US
Inventors: James O Mcmillan
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-05-15
Filing date: 1929-05-15
Publication date: 1931-08-04
Anticipated expiration: 1948-08-04

Description

Aug 4, 1931- J; o. MCMILLAN 1,817,698

UNLOADING DEVICE Filed May 15, 1929 2 SheBt's-Sheeb l m l O n U) ux n: i F 8 0` .tv

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4 Aug.- 4, 1931. J. o. McMlLLAN 1,817,593

UNLOADING DEVICE l Filed May 15, 1929 2 Sheets-Sheet 2 4R 31a/vanter J. o. MCMizzmg Patented Aug. 4, 1531 l i .l .i l i. j; Y .l l

UNITED STATES JAMES OQMCMILLAN; or WICHITA, Kansas UNLOADING DEVICE Appuation filed my i5, 1929. serial No. 363,214.

This invention relates to improvements in on the movement of the compressor piston for unloading devices for air or gas compressors, openin and closing the unloader. j and more particularly to a novel unloading Anot er object is to furnish an unloading device arranged in the discharge pipe of the device designed to unload the discharge pipe compressor and controlled by pressure in the so rapidly as to cause the ordinary check 55 compressorcylinder for automatically unvalve between the receiver 'and thecompressor loading the discharge pipe between the comto be instantaneously forced to its seat. Air presser and check valve whenever the comcheck valves of the dash pot type, often fail pressor comes to a stop. Such unloading deto seat, due to sticking caused by oil waste vice facilitates the starting of the compressor or carbon deposits, which sticking results in 00 against the load, thereby preventing the many other troubles. burning of the motor and transmission belt. Another object is to provide an automatic I have heretofore proposed a combination unloading device of durable and rugged concheck valve and unloader operating in the struction, simple and cheap to manufacture,

l5 discharge pipe of the compressor, and actunon-sticking, noni-clogging, and positive in o5 ated by the variations in the flow of air or gas action. 'y through the device; and the primary object It may be stated further that most unof the present invention is to provide an unloading devices inuse todayrequire adjusting loading device which is controlled by the means to have the device accord with the pressure in the compressor cylinder in startcompressor for which it is used. As inexperi- 70 ing, and by reduction of pressure in the unenced operators do not know how to properloading device back to the compressor cylin. ly adjust such devices, or the adjusting means der after the compressor comesto a stop for themselves become loose, and get out of order, unloadingthe discharge pipe. this results in the device becoming clogged',

Another important object of my invention therefore, it is a further object of this inven- 75 when used on small compressors, is to autotion to provide an unloading valve which is matically drain the watei` and oil Waste from fitted to the compressor and regulated autothe discharge line each time the compressor matically by the flow of air through the same, ceases its compressing operation. I am aware and which is not sensitive to clogging, due to that unloaders'of the bleeder type are in the fact that it has a large bleeding port. 30

general use, but suoli unloaders have given With the foregoing objects outlined and considerable trouble. The pressure switch with other objects in view which will appear bleeder valve is the type most generally in as the description proceeds,the invention conuse on automatic motor driven compressor sists in the novel features hereinafter deunits, and if the current fails or isswitched scribed in detail, illustrated in the accom- 85 oft while the installation is in operation, the panying drawings, and more particularly pressure switch remainsl closed, due to the pointed out in the appended claims.

fact that the pressure has not been built up Referring-to the drawings,

to the cut-out point. Consequently,` the Fig. 1 is a side elevation of a compressor 10 bleeder valve remains closed and the comand receiver, shown combined with one yform 9o pressoris not unloaded. Subsequently, when of my improved unloader. the current is resumed, under such conditions, Fig. 2 is an enlarged vertical sectional view, the installation. will start against full tank partly in elevation, of a portion of the unpressure, which causes blowing of fuses, buinloading device.

ing or jumping of belts, and sometimes a more Fig. 3 is a horizontal sectional view. on the .95 expensive occurrence, a burned out motor. l line 3-3 of Fig. 2.

My invention eliminates the possibilities Fig. 4 isa similar view of a modification. ofthe above mentioned troubles, slnce the op- Fig. 5 is a longitudinal sectional view of eration of the unloading device is independa special check valve forming part of the 5 ent of electrical means, and wholly dependent apparatus shown in Fig. 1| 10i In the drawings, 6 designates the cylinder of an air or gas compressor 7, which is driven by a motor 8, through the medium of a belt 9. The fluid compressed by the piston (not- .shown) of the compressor, is forced through the discharge pipe 10, into the receiver 11, and this discharge line is preferably provided with a manually controlled valve 12 and a check valve 13, the latter preventing any return of the compressed air or gas from the receiver to the compressor cylinder.

The parts 6 to 13 inclusive may be of conventional construction, and the present' improvements includes a T 14 which may beA chamber 15, as shown in Figs. 1 and 2, or

may be screwed directly into the T 14, as indicated at 19 in Fig. 4. vA port 20 inthe valve casing communicates .with a chamber 21 of the casing, in which a valve 22 operates. While this' valve may be of any suitable construction, it is preferably of the needle type, and its conical end 23 cooperates with an annular valve seat 24 provided at one end of the port 20. This valve has a disk 25 at one end which is pressed by a spring 26 against a flexible diaphragm 27 that is preferably clamped in position against one end of the casing by means of a threaded cap 28 which has an internally threaded port into which one end of the pipe 17 is screwed. The chamber 21 of the valve casing is in constant communication with the atmosphere by means of a pipe 29. As shown in Fig. 5, the pipe 17 is connected to the compressor cylinder by means of a special check valve This check valve `is constructed to bleed in opposite directions. Its valve housing 37 has two

valve seats

38 and 39 which cooperate with a ball 40. In this form of the in'- vention each valve seat has a

bleed groove

41, 42.' Consequently, with this form of check valve, while the compressor is forcing air through the pipe 17 into the chamber 36,

the passage of air will be delayed due to the bleed groove 41. On the other hand, during unloading, the groove 42 will restrict the passage of air from the chamber 36, and somewhat retard the unloading.

As shown in Fig. 4, the pipe 17 is connected to the compressorcylinder by' means of another form of check valve 30a which includes a tubular housing 31 that is internally threaded for connection with the pipe 17. This housing has an annular valve seat 32 that cooperates with a ball 33 which is forced towards the seat by a coiled spring 34. A bleed groove 35 extends along the bore of the housing from the valve seat toward the interior of the cylinder 6 for the purpose of delaying the return of the pressure luid'from the chamber 26 of the unloader valve' to the compressor cylinder.

In operation, it will be understood that the compressor 6 will force the air or gas through the discharge pipe 10, into the air receiver 11. The pressure fluid will not alone be forced through the pipe 10, but it will immediately be built up in the chamber 36 to close the valve 22 to prevent any bleedingof the air to atmosphere through the pipe 29, while the compressor is in action. While the compressor is in action, especially with small compressors, water and waste oil will gather in the chamber 15, and my improved mechanism functions not alone to unload the compressor but to discharge such water and oil waste.

When the pressure in the receiver 11 reaches a predetermined degree, the motor 8 is automatically stopped by the usual cut-out means (not shown). Immediately when this occurs, the unloader comes into operation,

and the check valve 13 is instantly forced to its seat to prevent any return of pressure fluid from the chamber 11 to the cylinder 6. As the compressor comes to a halt, the pres# sure in the cylinder 6 automatically lowers and consequently, the spring 26 forces the valve 22 away from its seat, so that pressure fluid in the conduit 10 and chamber 15 blows any water or oil waste out through the pipe 29 to atmosphere, and at the same time, it

yrelieves the system at the entrance side of the 'check valve 13 of pressure fluid.

As shown in Fig. 5, the pressure fluid in passing from the chamber 36 to the cylinder 6, will pass-through the bleed groove 42, and thus the releasing of the oil from the chamber 36 will be retarded tothe desired degree On small compressor units, it is important fto have what Ais termed an unloading chamber or cooler, and trap. This chamber traps much ofthe waste water and oil, it cushions the pulsations on the check valve 13, it cools the oil somewhat, and acts as an unloading chamber in that the com ressor must turn vover several times before uilding up vmuch of a pressure. In draining oil from this chamber, it has always been necessary to do `so by opening a cock by hand. In my improvements, this is done automatically each time the' compressor comes to a stop. When the compressor comes to a stop, the valve 22 is unseated, and the fluid in the chamber 15 is forced out through the pipe 29. After the fluid has been expelled, the air in the discharge line will also be released, and the system unloaded, cleaned and ready to be started. When the unloading chamber 15 is used, the

valve 22 will close on the first twoor three revolutions of the compressor, due to the fact thatI there is too much air space to be filled,y and very little pressure being produced on the side of the diaphragm 27, next to the chanber 21.

My unloadingl valve indicated in its entirety by 16, made in one size, will operate successfully on several sizes of compressors, but after a certain size compressor, the 'unloading valve should be a size larger 1n proortion to the next sizes of compressors it 1s to be used on.

My unloader is simple, durable and of rugged construction. It is cheap to manufacture, dependable, positive in operation, comprises only a few moving parts, and can be easily assembled, even by an unskilled person. No adjustments are necessary with the same. There is no sticking, and no clogging. Furthermore, when it includes the chamber 15, the latter forms an automatic waste eliminator.-

The terms and expressions employed herein are used as terms of description, and not of said line to the cylinder of the compressor, and an unloading valve interposed in said conduit and functioning due to pressure change in the compressor cylinder to unload the compressor and discharge line.

2. In an apparatus of the character described, a compressor cylinder havinga discharge line, a receiver connected to said line, a check valve interposed in said line for preventing pressure fluid from moving from the-receiver to the cylinder, a conduit connecting the cylinder to said line and connected to the latter at a point between the check valve and the cylinder, and unloader valve means interposed in said conduitl and functioning due to pressure change in the cylinder to release the pressure fluid from the discharge line and cylinder. f"

3. An apparatus as claimed in claim 2,

in which said conduit includes an unloader chamberfunctloning to gather wastewater and oil from the discharge line, the valve means being so arranged relatively to the unloader chamber as to discharge any water and oil waste from the unloader chamber when the unloader valve means opens.

4. An apparatus as claimed in claim 2, including a check valve arranged' in said conhav. `ing a discharge line, a conduit connecting and cluding. a check valve interposed invsaid conduit between the vunloader valve means and the cylinder, and functioning to allow the lgradual flow of pressure fluid from the valve means toward the cylinder.

V6."'An apparatus as claimed in claim 2, includinr a check valve interposed Vin said conduit lbetween the unloader valve means and the cylinder, and functioning to restrict the flow of ressure fiuid from the valve means towarthe cylinder, said last mentioned check valve comprising a notched seat and a valve member cooperating with said seat.

7. An apparatus as claimed in claim 2, including a check Valve arranged in said conduit between the unloader valve means and the cylinder, said last mentioned check valve including a housing provided with opposed seats; and a valve member interposed in the housing and cooperating with both of said seats.

8. An apparatus as claimed in claim 2, including a check valve arranged in said conduit between the unloader valve means and the cylinder, said last mentioned check valve including a housing provided with opposed seats, and a valve member interposed in the housing and cooperatino' with both of said seats, each of said seats low the flow of pressure fluid to pass the valve member when the valve member is seated.

. 9. An apparatus as claimed in claim 2, in which said unloader valve means includes a valve seat, a valve member cooperating with said seat, and a diaphragm cooperating with the valve member for forcing the same against its seat.v

10. In an apparatus of the character described, an unloader valve housing, a diaphragm arranged in the housing and dividing the interior of the same into first and second chambers, a port to place the first chamber in communication with a compressor discharge line, a valve seat for said port, a valve member cooperating with said seat and adapted to be forced against the latter by the diaphragm under fluid pressure created in the second chamber, and a second port communicating with the first chamber and' placing said first chamber in communication with the atmosphere.

11. In an apparatus of the character described, an unloader valve housing including a body having a removable cap, a flexible diaphragm arranged in said housing and clamped in position by the cap, said diaphragm dividing the interior of the body into first and second chambers, a port to admit pressure-Huid to the first chamber and provided with a valve seat, a port to admit a pressure iuid to the second chamber, a valve 'being notched to ali member movable with said diaphragm and arran ed in the first chamber and cooperating with said seat, said valve member functioning to move toward the diaphragm when moving away from said seat and another port placing the rst chamber in communication with the atmosphere.

12. In an apparatus of the character described, a compressor cylinder, a pressure fluid receiver, a'di'scharge pipe connecting the cylinder to the receiver, a check valve interposed in said pipe for preventing the How of pressure iuid from the receiver to the cylinder, an unloader chamber' connected to the discharge lpipe at a oint between the check valve and the cylin er and arranged to receive any liquid draining from the discharge pipe, an unloader valve connected tothe lower end of the unloader chamber, and functioning to discharge air and gas from the unloader chamber, and a conduit placing said last mentioned valve in commumcation with the cylinder, whereby pressure created in the cylinder is used to close said unloader valve. 13. A compressor unloader comprising a valve casing to be connected to the discharge of a compressor between the compressor and check valve, a diaphragm in the casing, a cap clamping the diaphragm to the casing and so forming with the latter up er and lower chambers, a valve member in t e upper chamber to open and close a port communicating the upper chamber with that of the compressor discharge, said casing having a second port communicating the upper chamber with the atmosphere, a pipe communicating the lower chamber with the compressor cylinder, a check valve in said pipe, means within the said check valve for automatically de- 0 laying the time for the compressor to take the full load by permitting the air from the compressor to escape to the atmos here through the unloading valve until su cient v speed has been attained to take the full load, whenever the compressor comes to a stop, means being provided in the check valve connected to the compressor cylinder for releasing pressure on the diaphragm of unloader to open a port communicating the compressor 5u discharge between the compressor and the discharge check valve to atmosphere as the compressor comes to a stop, and means for releasing an accumulation of waste oil and water, a quick release of air from the discharge line also forcing the discharge check valve to seat.

JAMES O. MGMILLAN.