US1864131A - Compressor unloading mechanism - Google Patents

Description

June 21, 1932. H. B. HALVORSEN COMPRESSOR UNLOADING MECHANISM Filed Oct. 29, 1928 fizz/with Ha? ZePYB. HlZum'Jen/ fig Auk ,4- mm,

Patented June 21, 1932 NETED STATES PATENT OFFICE HALBERT B. HALVORSEN, OF MICHIGAN CITY, INDIANA, ASSIGNOR TO SULLIVAN MACHINERY COMPANY, A CORPORATION OF MASSACHUSETTS COMPRESSOR UNLOADING MECHANISM Application filed October 29, 1928. SerialNo. 315,734.

The invention relates to compressor unloading mechanism and particularly to high pressure cylinder relief valve mechanisms for compound compressors. It is an object of the invention to provide an improved and simplified compressor unloading system. Another object is to provide improved high pressure cylinder relief valve controlling mechanism. Still another object is to provide an improved high pressure cylinder unloading mechanism, automatically controlled by fluid pressure in the intercooler. A more specific object is to provide an improved high pressure relief valve mechanism of extremely compact construction to facilitate manufacture and installation. Other objects and advantages of the invention will hereinafter more fully appear.

For purposes of illustration 1 have shown in the accompanying drawing one-embodiment which my invention may assume in practice.

In the drawing Fig. 1 is a diagrammatic view in side ele vation of an angle compound compressor having my invention associated therewith.

Fig. 2 is a fragmentary view of the high pressure cylinder at right angles to Fig. 1, showing part of the mechanism of my invention.

' Fig. 3 is a central vertical section on line 33 of Fig. 2 through an illustrative form of my improved high pressure cylinder unloading mechanism which is automatically controlled by fluid pressure in the intercooler. i

Fig. 4 is a central transverse section through this unloading mechanism on line 44 of Fig. 3. I

In the illustrative embodiment as shown in Fig. 1, the angle compound compressor is generally indicated at 1 and has a horizontal low pressure cylinder 2 and a vertically arranged high pressure cylinder 3. An intercooler 4t is connected with the low pressure cylinder by pipe 5 and with the high pressure cylinder by another pipe 6. The high pressure cylinder is shown discharging compressed fiuid into a receiver tank 7 through a discharge pipe 8. Any usual form of pilot valve controlled unloading mechanism may be employed for unloading the low pressure cylinder; Since the particular form of'the unloading mechanism for the low pressure cylinder forms no part of the present invention, it has not been described or shown in detail. Oneform which this unloader may assume is indicated at 9 which is a total clo sure inlet valve for controlling the intake of fluid through the opening 10, control be.- ing effected by a pilot valve P. V.

Novel means for unloading the high pressure cylinder a definite time after unloading of the low pressure cylinder will now be described. It will be readily understood that it is very desirable to allow the high pressure cylinder to operate effectively for a few strokes after the low pressure cylinder has been rendered ineffective, in order that the air remaining in the interco-oler under an intermediate pressure, may be pumped out. The necessity of relieving the high pressure cylinder when the compressor runs unloaded for any considerable length of time is readily understood by those skilled in the art. If this were not done, the high pressure cylinder would take in fluid from the intercooler at a fairly high vacuum and compress it up to thedischarge pressure. Thevery high ratioof compression which would take place would cause excessive heating and=possibly explosions. The novel mechanism illustrated herein comprises valve mechanism generally indicated by the member 11 having separate connections 12 and 13 with opposite ends of the high pressure cylinder. The interior of the valve housing has chambers 14 and 15 which are connected by passages 17 and 18 respectievly with a common vent or discharge pipe 16 which opens to the atmosphere.

Communication between the opposite ends of the high pressure cylinder and the atmosphere is controlled by meansof annular plate valve 19 and 20 which control series of ports 21 and 22 which connect the chamhere 14 and 15 with the respective connections 12 and 13. The plate valves close upon flat seats formed on the hardened plate memhers 23 and 24 and which surround theseries of ports .21 and 22 respectively. When these valves are free to move, the high pressure cylinder is rendered ineifective since the valve plates 19 and 20 may now act as outwardly opening check valves. In other words, the building up of a slight degree of pressure in either end of the high pressure cylinder will open the valve 19 or 20 to vent the end to atmosphere through chamber 14 or 15; but sucking of air back into the cylinder from the chambers 14 and 15 is prevented by the valves 19 and 20.

For the purpose of controlling these valves and holding them against their seats on the plates 23 and 24 during the time that the compressor is operating loaded, I have provided a novel fluid pressure operated mechanism which will now be described. 7 Since the construction is the same at both the upper and lower ends, only one end will be considered. Arranged on the opposite side of the valve 19 from its seat on the plate 23, I have provided a yoke 25, which is provided with an annular surface 26, adapted to' bear against the valve 19. The yoke 25 is guided in its movement by upwardly extending guides 27 cooperating with a recess 28 in the plate 23. The yoke at the other end, is attached by any suitable retaining means such as the bolt 29 to a flexible diaphragm 30. The diaphragm for the lower end is indicated at 31 and these two diaphragrns cooperate with an annular casing 35 to form a closed chamber which is connected by pipe 32 with the intercooler. The connection to the intercooler may be made at any convenient location. The diaphragms and 31 are clamped in position between the casing 35 and the respective valve housings. The passages 17 and 18 may, as shown in this preferred embodiment, be extended through the diaphragms, and continued so as to meet within the annular casing 35. The discharge pipe 16 is threaded into tne casing 35 and I communicates with the juncture of the pas-, sages 17 and 18. For the purpose of limiting the inward movement of the diaphragms and yokes, there is provided a central abutment 33, against which the bolt heads, holding the diaphragms in position, are adapted to strike. The difierent sections of the valve housing, the annular casing 35, the diaphragms 30 and 31, and the plates 23 and 24 are all held in assembled relation by means of longitudinally extending side bolts 34, which are shown in section in Fig. 4.

The operation of my improved relief valve controlling mechanism will now be described. Assume that the compressor is operating normally and it builds up a pressure in the receiver tank which will trip the pilot valve of the low pressure cylinder unloader. The unloader valve 9 is then closed and the low pressure cylinder rendered ineffective. 0on4 tinued operation of the compressor will cause a rapid reduction 1n pressure in the lntercooler, and after a few strokes this pressure will be reduced to about 4 or 5 lbs. per square inch above atmosphere. This pressure is of course, communicated to the diaphragms 30 and 31 and the holding pressure on the valves 19 and 20 is reduced to such an extent that the pressure within the high pressure cylinder, tending to open valves 19 and 20 will push back the yokes 25, 25 alternately, thereby venting the ends of the high pressure cylinder directly to atmosphere through chambers 14 and 15, passages 17 and 18, and the pipe 16. This will cause a still further reduction of pressure in the intercooler; and, as soon as the intercooler pressure is below atmospheric pressure, the yokes 25 are forced back by the atmospheric pressure in chambers 14 and 15, causing the bolts 29 to press against the abutment 33. The valves 19 and 20 are now permitted to operate freely as check valves and thus relieve both ends of the high pressure cylinder. When pressure in the receiver tank is reduced to the point required to cause the opening of the unloader 9, the low pressure cylinder will become eifective and cause a rapid building up of pressure in the intercooler. This pressure does not need to be materially greater than atmospheric pressure to cause the closing of valves 19 and 20 against the pressure in the high pressure cylinder, since the effective pressure area on each of the diaphragms is much greater than the opposed pressure area on one of the valves. Probably 5 or 6 lbs. would be sufficient with a practical design of the device. The valves 19 and 20 will thus be held closed by the diaphragms 30 and 31; and the intercooler pressure will build up to normal, and supply the high pressure cylinder. The operation of the high pressure cylinder unloading mechanism is thus made automatic and dependent upon the operation of the low pressure cylinder unloader, although it is not connected thereto.

As a result of my invention, it will be apparent that a very compact and simplified means has beendevised for effectively relieving the high pressure cylinder at just about the proper time. The device is very compact since it only comprises a single valve unit which may be easily installed.

While I have in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is 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 claims.

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

1. In a relief valve type unloading means for the high pressure cylinder of a compressor which comprises a low pressure cylinder, a high pressure cylinder, and an intercooler, in combination, an annular flat valve seat, an

annular plate valve mounted for limited movement relative to said seat,v and1fluid pressure operated mechanism controlled by fluid pressure in the compressor intercooler for controlling said plate valve,said.mechanism including a reciprocable member movable relative to said annular plate valve, said reciprocable member engaging said plate valve to hold the same seated during normal operation of the compressor and releasing said plate valve during unloading of the high pressure cylinder, and said plate valve controlling a vent from the high pressure cylinder.

2. In a relief type unloading means for the high pressure cylinder of a compressor which has a low pressure cylinder, a high pressure cylinder and an intercooler, in combination, relief valves one connected to each end of the high pressure cylinder to relieve pressure fluid pumped by the same, and means for v holding said valves closed during normal conditions in the intercooler, including a pair of movable members one cooperating with each relief valve, said movable members having each a surface subjected to intercooler pressure, said surfaces constituting walls of a common pressure chamber connected to said intercooler.

3. In an unloading mechanism for the high pressure cylinder of a compressor which has a low pressure cylinder, a high pressure cylinder, and an intercooler, in combination, relief valves one connected to each end of the high pressure cylinder to relieve pressure fluid pumped by the same, and means for holding said valves closed during normal pressure conditions in the intercooler, including a casing connected to the intercooler, said casing having Walls constituted by diaphragms one cooperating with each relief valve.

4. In an unloading mechanism for the high pressure cylinder of a compressor which has a low pressure cylinder, a high pressure cylinder, and an intercooler, in combination, relief valves one connected to each end of the high pressure cylinder to relieve fluid pressure pumped by the same, a pair, of yokes one cooperating with each relief valve for holding the same closed during normal pres sure conditions in the intercooler, a pair of diaphragms one connected to each yoke for actuating the same, and a casing defining a chamber formed with openings, two of said openings being closed by said diaphragms and a third being connected to the inter cooler.

5. A relief valve mechanism adapted to unload both ends of the high pressure cylinder of a compressor having a low pressure cylinder, a hi h pressure cylinder and an intercooler, comprising a casing, said casing providing a chamber with a plurality of openings, a pair of members each having a surface constituting a movable-wall closing one of said openings, means adapted to connect a third of said openings with the intercooler, and a pair of relief valve mechanisms, one controlled by each of said members.

6. In a relief valve mechanism for unloadingboth ends of the high pressure cylinder of a compressor which has a low pressure cylinder, a high pressure cylinder, and an intercooler, in combination, a valve casing having its opposite ends connected one to each end of the high pressure cylinder, a valve and valve seat in each end of said casing, a pair of diaphragmsmountedin said casing between said valves for holding the latter in closed position when said diaphragms are subjected to pressure, and means for subjecting said diaphragms to pressure in the intercooler.

7 L In an unloading system for a compressor having a low pressure cylinder, a high pressure cylinder, and an intercooler, a unitary relief valve mechanism for unloading both ends of the high pressure cylinder, comprising a valve casing having a centralchamber connected to the intercooler, diaphragms at opposite sides of said chamber subjected to intercooler pressure, a ported valve seat mounted in each end of said casing,.said seat-s communicating one with each end of the high pressure cylinder, annular plate valves one mounted for limited movement relative to each seat, and yokes one connected to each of said diaphragms and arranged tobear against one of said valves.

8. In a compressor unloading system, the combination as defined in claim 7 wherein each of said yokes is provided with means for guiding its respective annular plate valve. 9; Relief valve mechanism for unloading a high pressure cylinder of a compressor having alow pressure cylinder, a high pressure cylinder, and an intercooler, comprising meansproviding a passage connecting an. end of the high pressure cylinder to atmosphere, avalve mechanism for controlling said passage-comprising a. valve seat, a guard and a valve loosely disposed between. said guard and seat when the cylinder is unloaded, and meansresponsive to intercooler pressure for reciprocating said guard for holding said valve seatedwhen the pressure in the intercooler is above a predetermined point and for releasingsaid valve when intercooler pressure drops below a predetermined point 10. A relief valve mechanism for unloadi-ng both ends of the high'pressure cylinder of a compressor having a low pressure cylinder, a high pressure cylinder, and an intercooler, comprising a casing having two movable walls, a pair of relief valves controlling passages connecting the opposite ends of the high pressure cylinder to atmosphere, and means connecting each of said movable walls to a relief valve for controlling unloading ion izo

of the high pressure cylinder, said casing being connected to the intercooler whereby said relief valves are held closed when the intercooler pressure exceeds a predetermined amount and are released to vent fluid pressure pumped by the high pressure cylinder when intercooler pressure falls below a predetermined amount.

11. Relief valve mechanism for venting both ends of a high pressure cylinder of a compressor having a low pressure cylinder, a high pressure cylinder, and an intercooler, comprising opposed valve seats, valves cooperating with said seats and oppositely moving on opening, and actuating means for holding said valves seated during normal pressure conditions in the intercooler, said actuating means comprising a casing having two movable walls, one connected to each relief valve, said casing being connected to the intercooler.

12. In an unloading means for a doubleacting pump cylinder, means forming a pair ofpassages adapted to communicate with the ends of a cylinder, a pair of valves controlling communication of said passages with the at-' mosphere, and means for normally holding said valves closed including means forming a pressure chamber having oppositely movable walls and means through which said walls Ina-y respectively move said valves to closed position.

13. In an unloading means for a pump cylinder, means forming a passage adapted to communicate with an end of the pump cylinder, and mechanism for controlling communication of said passage with the atmosphere including a valve seat, a coaxial valve guard and guiding member, a valve member cooperating with said seat and guided and limited in its movement relative to the seat by said guard and guiding member, and means for moving said guard and guiding member relative to said seat to clamp the valve'on the seat. I

14:. In an unloading means for a pump cyl inder, means forming a passage adapted to communicate with an end of the pump cylinder, and mechanism for controlling communication of said passage with the atmosphere including a valve seat, a coaxial valve guard and guiding member, a valve member cooperating with said seat and guided and limited in its movement relative to the seat by said guard and guiding member, and pres sure fluid operated means for moving said guard and guiding member relative to said seat to clamp the valve on the seat.

15'. In an unloadingmeans for a double acting pump cylinder, in combination, means forming a pair of passages adapted to communicate with the ends of a cylinder, a pair of valves controlling communication of said passages with the atmosphere, and means

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