US1708171A - Compressor-unloading means - Google Patents

Description

p 9, E929. H. B. HALvoRsEN COMPRESSOR UNLOADING MEANS RJQSJIH Filed Feb. 25, 1924 2 Sheets-Sheet l Eig.

pf 9, 1929. H.v B. HALvoRsl-:N LMSJ'H COMPRESSOR UNLOADING MEANS Filed Feb. 25, 1924 2 sheets-sheet 2 Patented Apr. 9, 11929..

narran stares y avea-,ui rarest ermee.

HALBERT B. HALVORSEN, QF MICHIGAN CITY, INDIANA, A/SSIG-NOR TO SULLIVAN MACHINERY COMPANY, A CORPORATION F MASSACHUSETTS.

COMPRESSOR-UNLOADING MEANS.

Application led February 25, 1924.- Serial No. 694,926.

4 compression ot' any air which might leak past the intake unloader valve when the compressor 1s turning over unloaded from a partial vacuum to receiver pressure. Other ob- ,jects and Vadvantages of my invention will be apparent in the course of the following specitication and appended claims. Y

In the accompanying drawings I have sho wn for purposes of illustration several embodiments which my invention may assume in practice.

ln these drawings,-

Fig. 1 is a sectional view through one illustrative embodiment of my improved unloading mechanism.

Fig. 2 is a similar section on the line 2 2 of Fig. 1.

Fig. 3 is an end view ofthis mechanism.

'F ig. 4 is a sectional view through a diftferent illustrative form on a plane corresponding to vthe line 4 4 of Fig. 6, parts being shown in elevation.

Fig. 5 is a section on the line 5 5 of Fig. 6.

Fig. 6 is an end view with a portion eut away to show details of the construction of this second illustrative `form of my invention.

Fig. 7 is a view corresponding to Fig. 4 through a third form.

As the details of construction of compressors with which mechanism of this type may be used are so Well known, it seems unnecessary to illustrate one of these mechanisms in 4position upon a compressor. The general disposition of these devices may, however, be observed if necessary in the patent to H. C. Johansen, 1,404,176,- patented J an. V17, 1922.

Compressors of the type With which thisIl mechanism is used vcomprise W and high pressure cylinders connected by an intercooler, and the low pressure cylinder intake is controlled by an intake closure valve. As a result, when the compressor is unloaded, if the valve does not seat perfectly tight, there is some small leakage of air int-o the low pressure cylinder but this is not of sutieient quantity to maintain the inter-cooler pressure as high as atmospheric pressure, for the high pressure cylinder keeps this pumped down to quite a substantial vacuum despite the leakage. As a result, what little air does leak in must be compressed in the high pressure cylinder :trom a partial vacuum up to receiver pressure; and there is thereby produced a very high tempera ture on account ofthe number of compressions, with resultant burning of the lubricant, dama-ge to valves and other injurious consequences. For the purpose of avoiding the compression 'of any air lwhich may leak in, and to vent it to the atmosphere whenever thepressure exceeds atmospheric, I have devised the invention, three illustrative forms of Which are shown herein.

As a preliminary it may be stated that these three forms diii'er from each other primarily in that use has been made of three different types of valve mechanism, namely, the end seating or poppet type, the slide type, and the piston type, in the three forms. Taking up the first form which is shown in Figs. l, 2 and 3, it will be observed that it comprises a casing 1 from whose opposite sides pipes 2 and 3 lead to the counterbores or clearances at the opposite ends of a high pressure cylinder of a compressor. The pipes 2 and 3 open into chambers 4 and 5 respectively which are arranged at opposite sides of a chamber 6 which opens into a larger chamber 7. Chamber 7 is in turn connected by a series of ports 8 controlled by a thin annular valve 9 with a recess l formed in a cap member 11, there being an opening 12 leading to the atmosphere through the cap member 11. A spring 13 transversely Hexed and held in position by a machine screw 14 serves'to maintain the valve "9 normally seated but permits it to open when the pressure Within the chamber 7 is substantially above atmospheric pressure. Between the chambers 4 and 5 and the chamber 6, therearc arranged a pair of valve seats 15 and 16 respectively, these being coaxial with each other. Valve means including a pair of coaXially arranged valves 17 and 18 connected by a stem portion 19 and mounted upon the upper end of a piston 20 are adapted to seat upon the seats 15 and 16 and interrupt communication between lines 2 and 3 and the chamber 6. It will be observed that the piston 2() is reeiproeable in a cylinder 21, that it is normally held in the position shown in be at once'readily apparent. When the coinpressor is running loaded the pressure in the intercooler will be substantially above atinospheric, probably approximately one-halt the desired pressure to which the high pressure cylinder compresses the fluid pumped. Accordingly, at this time the Apiston 20 will be held up both by the intercooler pressure and by the pressure of the. spring 22; and the maX- imum pressure communicated from the high pressure Cylinder acting upon the much smaller effective area of valve 17 exposed thereto will be insuflicient to open the valves. When, however, the compressor is Funloaded and the intake closure valve operates to discontinue the admission of fluid to the compressor intake, the intercooler pressure will rapidly fall to less than atmospheric and accordingly the' piston 20 will be moved downwardly; and the two ends of the cylinder will then be connected to each other through the lChamber 6; and when the pres ire in the cylinder exceeds atmospheric pressilre it will force the valve 9 off its seat and pass to the atmosphere through the passage 12. lVhen the compressor isre- 'loaded and as soon as the intercooler pressure builds up to the necessary degree, the .valves 18 and 17 will seat and the compressor will operate in a normal manner. It should be noted that a counter-bore 26 is provided at the lupper end ofthe bore '21 and if this is connected by a small port,26 to the atmosphere the opening of the valves will be more positive and continuous during unloaded running.

In the form of my invention shown in Figs. 4, 5, and 6, instead of using a pair of end seating valves to control communication between the pipes 2 and 3, and between them and the atmosphere, I have provided slide valve mechanism for accomplishing this same function. Herein it will be noted that the parts 20, 21, 22, 23, and 24, 25 and 26, are to all intents and purposes identical with those previously described and referred to by these saine numbers, but instead of employing the poppet valves a pair of slide valves 31 and 32 are provided. These valves are reciproeable in ehamberst33 and 34 respectively communieating with the pipes 2 and 3 and opening through ports 35 and 36 into a recess 37 corresponding to the recess 8. A suitable valve 39 and spring 40 are provided for controlling the venting of fluid tothe atmosphere; and a suitable atmospheric vent 41 corresponding to the vent 12 may further be provided. It will be noted that the ports 35 and 36 open through a flat valve seat surface 42 and that the valves have flat faces 43.and 44 cooperating with these seais. The valves are held in position by parallel lugs 45 seating in cutaway por- 70 tions 46 on a stem 47 projecting upwardly from the piston 20, and springs 48 lodged in recesses 49 within the stem maintain these valves seated. As the mode of operation vis precisely like that previously described except that upon unloading the valves move downwardly and uncover the passages 35 and'36 by sliding off them, no further description of this form of my invention seems necessary.

In Fig. 7 a still further and more pro- 80 nouncedly modified construction is presented. In this case the pipes 2 and 3 leading to the counterbores at the opposite ends of thecylinderl open into annular groovesn 52 and 53 formed in the inner .walls of a eyljndrically g5 bored housing 54. Within the bore 55 of this housing a piston 56 is reciprocable, and this piston is normally maintained in the position shown in Fig. 7 by a. spring 58 which cooperates withian Vadjustable follower 59 at its 90 elower end. This'follower is adjusted by a screw 6'0 in a manner similar to the adjustments of the previously describedsprings. A

' connection 6 1 leads oil to the intcnplgr from the space within the bore 55 at the lo er side 95 of the piston 56. At its upper side the piston i, 56 carries 'an upwardly extending -boss 62 which at its extreme upper end-is provided with an enlarged portion providing a valve seating surface 63 upon which an annular 100 valve 64 is normally held seated by a resilient bowed spring 65 held in position by'a screw 66. A cover 67 threaded as at 68 to the top of the casing member 54\encloses the valve mechanisin and provides a shoulder 69 against which the, outermost portion of .the valve seat is adapted to rest. An atmospheric vent is shown at 70 from the chamber 71 in which the valve is mounted. The space between-the enlarged portion carrying the valve seat 63 and 110 the. portion 56 is sufficient to connectv the grooves 52 and 53 when the parts have moved to bottom position.

In the operation of this mechanism it will be evident that when intercooler pressure falls below atmospheric pressure to the iequisite degree, the piston 56 and all the connected parts will move downward, and that the piston, having `moved downward, will uncover the annular grooves 52 and 53 and 12e they will. be freely in communication with each other through the space surrounding the boss 62. As the piston moves downward its valve seat portion will also move downward in a like manner and as a result there will 'occur a separation between the valve seat and the shoulder 69.r Any `pressure admitted to cient to overcome the pressure of the spring 65 will unseat the valve 64 and be vented to the atmosphere. On reloading, the parts will move up to the position shown in Fin'. 7 again.

It will be evident that in all forms otmy invention which I have illustrated herein there will be an automatic avoidance of any harmful temperatures, and that the opposite ends of the cylinder willbe brought into communication with eachother before the pressure in the intake to the high pressure cylinder is lowered to any substantial extent below atmospheric pressure. It is furthermore evident that simultaneously with the opening of communication between the ends of the cylinder, an outlet to the atmosphere is provided for the fluid as fast as it reaches a little above atmospheric pressure.

While I have in this application specifically described several embodiments which my in- .vention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended clai-ms.

What I claim as new and desire tosecure by Letters Patent is:

1. In an unloading mechanism, in combination, a casing having chambers respectively communicating with the opposite ends of a compressor cylinder, an intermediate chamber communicating with the atmosphere, valve means operative to connect said first mentioned' chambers with said intermediate chamber and through the latter with each other, and means directly responsive to intercooler pressure for controlling the position of said valve means.

'2. In an unloadingmechanism, in'combination, a casing having chambers respectively communicating with the opposite ends of a compressor cylinder, an intermediate chamber communicating with the atmosphere, end seating valve means operative to connect said first mentioned chambers with said intermediate chamber and through the latter with each other, and means directly responsive to intercooler pressure for controlling the position of said valve means.

3. In an unloading mechanism, a casing having chambers respectively communicating with the opposite ends of a compressor cylinder, an intermediate chamber communicating with the atmosphere, end seatlng s1- multaneously movable valve means operative to connect said Iirst mentioned chambers with said intermediate chamber and through the latter with each other, and intercooler pressure responsive means for controlling the position of said valve means. c

4. vIn an unloading mechanism, a casing havingl chambers respectively communicating with the opposite ends of a compressor cylinder, an intermediate chamber communieating with the atmosphere, end seatingvalve means simultaneously movable in the same directions and operative to connect said first mentioned chambers with said intermediate chamber and through the latter with each other, and intercooler pressure responsive means for controlling the position of said valve means. i

5. In an unloading mechanism, a casing having chambers respectively communicating with the opposite ends of a compressorcylinder, an intermediate chamber communicable with the atmosphere, spring loaded valve means controlling said communication, valve means loperative to connect said lirst mentioned chambers with said intermediate chamber and through the latter with each other, and intercooler pressure responsive means for controlling the position of said valve means.

6. In an unloading mechanism, a casing having chambers respectively communicating with the opposite ends of a compressor cylinder, an intermediate chamber communicable with the atmosphere,` spring loaded valve means controlling said communication, end seating valve means operative to connect said first mentioned chambers with said intermediate chamber and through the latter with each other, and intercooler pressure responsive means for controlling the position of said valve means.

7. In an unloading mechanism, a casing having chambers respectively communicating with the opposite ends of a compressor cylinder, an intermediate chamber communicable with the atmosphere, spring loaded valve means controlling said communication, end seating simultaneously movable valve means operative to connect said lirst mentioned chambers with said intermediate chamber and through the latter with each other, and intercooler pressure responsive means for controlling the position of said valve means. l

8. In an unloading mechanism, acasing having chambers respectively communicating with the opposite ends of a compressor cylinder, an intermediate chamber communicable with the atmosphere, spring loaded valve means controlling said communication, end seating valve means simultaneously movable in the same directions and operative to connect said first mentioned chambers with said intermediate chamber and' through the latter with each other, and intercooler ,pressure responsive means for controlling the position of said valve means.

y 9. In an unloading mechanism, means forming a pair of chambers respectively communicating with the opposite ends of a high pressure cylinder, each of said chambers being further provided with 'a port adapted to connect the same to the atmos- Cii phcie, valve means respectively controlling said atmospheric ports, and a single actuating means directly controlled by lntercoolerY vJressure c Vlinder atmos )heric vent means l a a valve means respectively controllingl comn'iunication of said chambers with saidatmospheric vent/means, and means including a single piston normally held in position to close said valve means and movable in accordance with pressure variations resulting from unloading for simultaneously moving` said valve means to open positions.

12. In an unloading mechanism, a casing having chambers respectively communicating with the opposite ends of a compressor cylinder, atmospheric vent means, valve means controlling the intercommunication between said chambers and their communication with said atmosphericvent meansand common means controlled by pressure variations resulting from unloading for controlling `the position of said valve means and operative to effect such intercommunication between said chambers.

13. In an unloading mechanism for the high pressure cylinder of a compound compressor, a casing.. having chambers respectively communicating with the opposite ends of a compressor cylinder, atmbspheric vent means, and means movable in accordance with variations in pressure growing out of unloading the compressor forsimultaneously providing access between said chambers and with said atmospheric vent means.

14. n unloading mechanism adapted for connection to a compressor cylinder comprising multi-valve means movable as a unit to effect an unloading controlling function simultaneously with respect to the two ends of acompressor cylinder, and vacuum controlled means for effecting the movement of said valvemeans.

15. An unloading mechanism adapted for connection to a compressor cylinder comprising means forming uid conducting passages adapted to communicate respectively with the end s of a compressor cylinder, valve means individual to each passagevfor controlling flow of fluid from the compressor to the atmosphere by way of said passages, common means .for always maintaining said valve means m an open position while the compressor is vunloaded to permit'uid in said compressor to bedischarged to the atmosphere, and one-way flow control means for preventing back flow of fluid to said compressoi'. l

16. An unloading mechanism adapted-for connection to a compressor cylinder comprising means forming fluid conducting 'passages adapted to communicate respectively with the ends of la compressor cylinder, valve means for interconnecting'said passages and for connecting the same to atmosphere whereby the ends'ofthe compressor cylinder may be placed in communication with each other and the fluid in the compressor discharged to the atmosphere, and one-way flow cont-rol means .connection to a compressor cylinder comprising a casing provided with fchambers adapted for'cennection respectively with the ends-of a compressor cylinder, means comprising a unitary valve mechanism for interconnecting said chambers and connecting the same to atmosphere whereby an unloading function with respect to both ends of the cylinderis effected simultaneously, and intercooler pressure-responsive means for con-` trollinr said unitary valve mechanism. 18. n unloading mechanism adapted for connection to a compressor cylinder operative to effect unloading by venting and to allow communication between the ends of a compressor cylinder including passage forming means adapted for connection to the opposite ends of a cylinder, and a unitary valve mechanism for controlling intercommunication between said passage forming means and effecting unloading by venting.

19. An unloading mechanism adapted for.

connection to a compressor cylinder comprising valve means movable as a unit to interconnect the ends of a compressor cylinder, and means controlled by cylinder intake pressure controlling said valve means.

In testimony whereof I aiix my signature.

HALBERT B. HALvoRsEN.

CERTIFICATE 0F CORRECTION.

Patent No. 1,708,171. Granted April 9, 1929. to

HALBERT B. HALVORSEN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 4, line 101. claim i8, for the word "communication" read intercommunication", und line 105, for the word "interconununication" read "communication"; and that 'the said Letters Patent should he read with these corrections therein that the same may conform to the record of the case inV the Patent Office.

Signed and sealed this 7th day of May, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

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