US1769667A - Compressor-unloading means - Google Patents

Description

y 1; 6 H. B. HALVORSEN 1,769,667

COMPRES SOR UNLOADING MEANS Filed Feb. 25, 1924 2 Sheets-Sheet 2 v 5 w E 11/.

Patented duty i EQidfi wearer HALBERT B. HALVQRSEN, 3F MICHIGAN II TY, INDIANA, ASSIGNQB T6 SULEWAN NAOHINERY GQMPQANY, A COR'PQRATION OF MASSACHUfiETT COMPRESSQB-UNLDENG MEANS Application filed Febrnaryfifi, MM. Serial Na'QMflW.

My invention relates to compressor unloading means.

An object of my invention is to provide an improved compressor unloading means & and more especially an improved compressor.

unloading means of the auxiliary unloader type adapted to be used with a compressor having an intake t pe unloader and having for its particular unction the avoidance of shown for purposes of illustration. several.

v:forms which my invention may assume in practice.

In these drawings Fig. 1 is a central section through one illustrative form of my invention.

Fig. 2 is a view of a compressor provided with this illustrative form of'my invention.

Fig. 3 is a view of a somewhat similar modification incentral section.

Fig. 4 is a fragmentary view on an enlarged scale illustrating the connection of this last mentioned modification tothe high pressure cylinder of a compressor.

Fig. 5 is a central sectional view on the line 5'-5 of Fig. 6 through a further modification.

Fig. 6 is a central sectional view through the mechanism of Fig. 5 taken on a plane corresponding to the section line 6-6 of Fig. 5.

Fig. 7 is a sectional view similar to that of Fig. 6 showing a further modification.

Fig. 8 is an elevational view of the high pressure cylinder of a compressor, illustrating the application of theforms of my invention shown in Figs. 5, 6 and 7 thereto.

It will be understood that in the event that there is any leakage past the intake closure valve 1n a compound compressor, there will be very undesirable consequences in the high -pressions that take place.

pressure cylinder unless some/special auxiliary means is provided therefor, for the high pressure cylinder will pump down the pressure in the intercooler to a partial vacuum notwithstanding any ordinary leakage and so, if such means is not provided, the high pressure piston will compress air from a partial vacuumnp to full receiver pressure and a very hi h temperature will be developed due to t e number of com- For the purpose of preventing any such undesirable results, I have disclosed the several different forms referred to above, each of which constitutes means for venting the ends of the highpressure cylinder of a compound compressor when the latter is running unloaded and as. soon as the pressure in the high pressure cylinder becomes a little above atmospheric pressure. I

In Fig. 2 there is shown a compressor provided with one of the illustrative forms of my invention, the same being generally designated 1 and comprising'a low pressure cylinder 2 discharging to an intercooler 3, with which a high pressure cylinder 4 is connected bya pipe 5. Mounted upon the higlh pressure cylinder 4 is an unloading mec anism generally designated 6 and including a casing 7 having chambers 8, 9 which are connected by pipes 10' 11 respectively with the counterbores or othcr'suitable points at the lower-and upper ends of the cylinder 4. Between the chambers 8 and 9 is a third chamber 12 which communicates with the surface 15 w ichprovides valve seats 16 and 17 respectively surroundin .a'series of ports 18 and 19 opening from t e chambers 8 and 9 into chamber 13. Midway between the valve seats 16 and 17 there is arranged a seat 20 for a. poppet type valve 21 which is carried upon, a stem 22 guided as at 23 and adapted to be moved by a piston 24.- reciprocab e in. acylinder 25 arr ed coaxial with the valve stem. This cylinder 25 is vented to the atmosphere 'by'means of a Ill port and is connected at a point above the piston'24 with the intercooler by means of a connection 26. A spring'27 surrounds the stem. 22 and acts between an abutment 28 on the casing 7' and a shoulder 29 at the lower end of the stem and the piston 24 on moving upwardly is adapted to engage the lower extremity of the stem and. raise it and with it the valve 21. Arranged upon 4 low pressure cylinder '2 is provided is closed sothat the compressor has ceased to pump any fluid into the intercooler except such as may leak by the intake closure valve, it will be evident that the high pressure cylinder 4 will soon produce a partial vacuum in the intercooler 3 and as quickly as this happens the piston 24 will be moved upward against the pressure of the spring 27 by the atmospheric pressure acting upon its lower side with the result that the valve 21 will be unseated and the chamber 13 will be placed in free cornmunicationwith the atmosphere throughthe passage 12. -Thereafter, as soon as there is any compression of the air which may leak ast the intake closure valve to even a sma l degree above atmospheric pres sure, the valve 30 or the valve 31 'will be unseated' at such time as this pressure is reached and will discharge the airto the atmosphere. As a result, it will be evident that the number of compressions which can take place is decidedly reduced and the danger of burning of the lubricant and injury to the parts by high temperatures is totally prevented.

The form of my invention shown in Figs. 3 and 4 differs from that shown in Figs. 1 and 2 only in that the chan es in pressure in the highpressure cylin er proper are relied upon to effect the operation of the atmospheric vent means. The structure,

with the exception of the means for eilectiug upward movement of the piston which controls the atmospheric vent valve,.is identical with theparts previouslydescribed and accordingly it is unnecessary to restate any part of this structure. It will be observed that instead of employing the connection 26 to the intercooler there is provided a connection from each of the chambers 8 and 9 to the .s ace above the piston 24, these connections ing respectively designated 38, 39 and being controlled by simple plate valves of thinflexible material" 40 cooperating with seats 41, to prevent thepassage of amass? ing portions 42- which serve to center them 7 while permitting the passage of fluid past the valves when the latter are unseatedu Springs 43 are provided to maintain the valves 40 normally seated, these being held in position by plugs 44.

Now considering the mode of operation of this form of my invention it will be observed thatupon the closure of the intake controllin valve the pressure in the intercooler will speedily be pumped down to less than atmospheric pressure and accordingly the movements of the high pressure piston will produce a partial vacuum at the end of the cylinder away from which the piston is moving at any given moment. When the pressure is thus reduced it is obvious that h it will be correspondingly reduced in the chambers 8 and 9 and accordin ly the pressure above the piston 24 wil force the valves 40 off their seats and pass into the low pressure spaces at the ends of the cornpressor high pressure cylinder. As soon as the pressure above the piston 24 is sufiiciently reduced the latter will move upwardly and engage the stem 22 with the result that the valve 21 will be unseatedc Thereafter, since there will be a artial vacuum during each suction stroke, t e piston will be maintained in raised position until the compressor is reloaded notwithstanding the fact that there may be pressures at the end of the compression strokes sufiiciently high to momentarily unseat the valves 30 and 31, During the unloaded running of the com;- pressor, it will be evident that any pressure which may tend to be built up within either end of the compressor cylinder will be vent ed to the atmosphere very soon after it at tains a ressure equal to atmospheric pres sure and there will therefore be no possi bility of an undesirable range of compression which would result were these vent means not provided. -When the compressor is reloaded there will no longer. be any tendency for fluid to flow from above the piston 24 to the opposite ends of the cyl inder and 'asthe piston 24 15 not a perfectl tightlfit for its cylinder, the leakage throng leakage around the stem 22 a so which would aid in this edect.

In Figs; 5, 6 and 8, a still further form of my improved construction is illustrated, w 11 e in Fig, 7 the structure is substantially the same as that in the figures just menone end of the high pressure cylinder is tioned, but there is a small" change which will be noted. In these species of my invention it will be observed that a relief valve is arranged at each end of the high pressure compressor valves comprising casings 51, which casings are supported by the pipes 52 which connect certain chambers within the casings with the counterbores or other similar parts of the compressor high pressure cylinder. Within the casings 51 there are arranged three alined chambers, respectively 53, 54,

55, a discharge chamber 56 and a passage or communication chamber 57. The chamber 53 which is connected by the pipe 52 with spaced by a septum 58 from the chamber 54,

this septum providing a valve seat 59 with p which a valve 60 cooperates. The chamber 54 is separated by a septum 61 from the discharge chamber 56, and passages 62lopening through a valve seat 63 in the chamber 56 serve to conduct fluid from the chamber 54 into the chamber 56. Suitable sprin closed annular valves 65 yieldingly hel closedby transversely flexed springs 66 normally close the communication between chambers 54 and 56. Atmospheric dichar passages '67 lead from the chambers 56. T e valves 60 are connected b chambers 55, these istons being normally held in the position s own in Fig. 5 with the valve 66 seated upon itsseat 59 by springs 70. The space within the chamber 55 above the piston communicates by way of the passage 57, a port 71, avalve chamber 72, and

. the port 73 with the space 53. Within the valve chamber '72 is a valve seat 74 with which a plate valve 75 of the t pe previously described cooperates, whic valve is normally maintained seated by the spring .76 and serves to permit flow from, but not towards, the chamber 55.

From the description given it will be at once apparent how this mechanism operates, when it is observed that there is an opening 77 admitting atmospheric pressure to the lower side of the piston 69. Assume that the compressor is unloaded and that a partial vaccuum is drawn in one end of the high pressure cylinder during one stroke of the piston. This will cause thevalve 75 to be unseated by the pressure in the passage 57 and chamber 55 and if the compressor continues to run unloaded, the pressure above each piston 69 will be reduced to such an extent that the pistons will move 11 wardly while the valves 75 will maintain the pressure less than atmospheric in. the passage 57 Accordingly upon the discharge,

strokes, it will at once result that the ressure" in the chamber should it excee atmospheric will be free to pass the valve 60 and enter the chamber 54 whence it may cylinder, these relief.

stems 68 with pistons 69 which are reciprocable in the passthrough ports 62, valves 65 and so to the atmosphere through the opening 67.

Each end or" the cylinder-herein provides its own unloading mechanism. The valve 65 prevents back flow of air into the cylinder.

. As to the form of this mechanism shown in Fig. 7 it differs from that shown in Fig.

free movement relative to the stem. Theeneral mode of operation is, however, identical with the form shown in Figs. 5, 6 and 7, Here also it will be observed that the movement of the piston to effect the closure of the valve 60 is accomplished by reason of leakage past the pistons or along the stems 68 or 68".

In connection with Figs. 5, 6, 7 and 8 it may be noted the chambers 57 of the mechanisms at the opposite ends of the high pres sure cylinder may be connected b a pipe connection 79 (see Fig. 8), this being done for the purpose of effecting the unloading at the opposite ends 'of the cylinder uniformly.

their respective pistons 24, 69 and 78 must be selected-so that the product of the efiective area of the pistons multiplied by the difference between atmospheric pressure and the sub-atmospheric ress ure produced as a. result of -unloading o the low pressure cylinder will exceed the product of the pressures valves Q1 or 60 multiplied by the effective area of those valves. The present drawings are illustrative of positional relations, and changes appropriate to the conditions of operation are to be made in accordance with the foregoing principle.

In all the forms of my invention it will be observed that means is provided of very simple construction which automatically takes care of the condition which may grow out of a. leaky intake closure valve and which results' in a really complete unloading of the compressor and the prevent-ion of any possible in'ury due to high temperatures.

While I ave in this application specifically described several forms which my inven-' tion 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 withoutv 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. An unloading mechanism comprising a casing provided with a chamber which has an outlet to the atmosphere, a valve opening against fluid pressure in said chamber forcontrellin said outlet member controllin 25 acting during loaded operation upon the v tainin the outlet valve, means for normally mainsaid outletvalve closed, and means for su jecting said member to subatmospheric pressure to efiect movement thereof to .open the outlet valve includingcheck' valve controlled passages adapted for connection to the opposite endsol a cylinder.

2. In a compressor unloading mechanism comprising a casing having a chamber adapted for communication with one end of a compressor cylinder, a chamber in constant communication with the atmosphere, a chamber intermediate said first and second mentioned chambers, a check valve opening. toward the second mentioned chamber controllin communication between said second and third mentioned chambers, a valve controlling communication between said first and; third mentioned chambers, a fourth chamber, a piston therein operative to efi'ect opening of said second mentioned valve, and a check valved connection between said piston containing chamber and said first mentioned chamber.

3; In an unloading mechanism comprising a casin having a chamber provided with an atmosp eric vent, chambers at the opposite sides of said first mentioned chamber adapted for connection with the o posite ends of a compressor cylinder, a c amber communicable with all three-of said previously mentioned chambers, check valves openin toward said last mentionedchamber control ing the communication therewith of said second mentioned chambers, a valve controlling communication between said fourth chamber and said first chamber, and means operativeto open said valve.

4. In an unloading mechanism com rising a casing having a chamber provide with an atmos heric vent, chambers at the oposite si es of said first mentioned chamr adapted for connection with the opposite ends of a compressor cylinder, a champ with an atmospheric vent, chambers at the her communicable with all three of said previously mentioned chambers, check valves opening toward said last mentioned chamber controlling the communication therewith of said second mentioned-chambers, a valve controlling communication ing said last mentioned side to pressure greater than and less than atmospheric. 5. In an unloading mechanism compris mg a casing having a chamber provided opposite sides of said first mentioned chamber adapted for connection with the opposite ends of a compressor cylinder, a chain manner her communicable with all three of said previously mentioned chambers, check valves opening toward said last mentioned chamsaid valve including a piston constantly subjected on one side to atmospheric pressure, a spring adapted to oppose movement of said piston, and means for intermittently subjecting the opposite side of said piston to pressures equal to and less than atmospheric.

6. In an unloading mechanism comprising a casing having a chamber provided with an atmospheric vent, chambers'at the opposite sides of said first mentioned chamber adapted for connection with the opposite ends of a compressor cylinder, a chamber communicable with all three of said previously mentioned chambers, check valves opening toward said last mentioned chamber controlling the communication therewith of said second mentioned chamhere, a valve controlling communication between said fourth chamber and said first chamber, and means operativeto open said valve including a filth chamber, a piston therein subjected constantly on one side to atmospheric pressure and alternately subjected on its other side to ressures equal to and less than atmospheric and also including check valved connections between said second mentioned chambers and said filth chamber. 7

'Z. An unloading mechanism, adapted for connection to a compressor cylinder, com rising valve means adapted to efiec't an an cod ing controlling liinction for a compressor, means whereby said valve is always maintained in an open position while the compressor is unloaded to permit fluid in connected compressor to be discharged to atmosphere, and a plurality of valves for preventing baclr fiow of fluid to the 3lllpressor while unloaded.

8. A compressor unloading mechanism comprising a casing having separate valves posits ends of a compressor cylinder with which said casing is adapted for connection, valve means therein for controlling discharge to the atmosphere from said ends, and vacuum responsive means therein 'l'or actuating said latter valve means. a 9. A compressor unloading mechanism comprising chamber forming means adapt ed for communication with a compressor cylinder, means therein for controlling disc arge o'l lluid to the atmosphere from the cylinder to which it is connected aid to ell feet unloading thereof, said latter means including a plurality of valves opening intill lllti lllli Hill . port, a member controlling said latter valve,

- inder,

wardly of said chamber forming means, one of said plurality of valves being a check valve adapted to trap fluid pumped into said chamber forming means from said cyl- ,10. A compressor unloading mechanism comprising chamber forming means adapted for communication with a compressor cylinder and adapted to be subjected to pressure existing in the cylinder with which it has communication, means for controlling the unloading of said compressor including a plurality of valves opening inwardly of said chamber forming means, one of said plurality of valves being a check valve for interrupting return flow from said chamber forming means to said \cylinder.

. 11. A compressor unloading mechanism comprising chamber forming means adapted for communication with a compressor cylinder and adapted to be subjected to pressure existing in the cylinderwith which it has communication, means for controlling the unloading of said compressor including a plurality of valves opening inwardly of said chamber forming means, and means whereby one of said valves is adapted to be seated while the other is open.

for maintaining said latter valve closed, and means for sub ecting said member to subatmospheric pressure produced by said compressor cylinder to efiect movement thereof to open said latter valve.

In testimony whereof I afiix my signature.

HALBERT B. HALVORSEN.

12. A compressor unloading mechanism comprising a casing having a chamber adapted for communication through a check valve controlled passage witha compressor cylinder and through a port to the atmosphere, a valve opening against fluid pressure in said chamber for controlling said means for'normally maintaining said latter valve closed, and means for subjecting said member to sub-atmosphericpressure to ef- 7 feet movement thereof to open said latter valve.

13. A compressor unloading mechanism comprising a casing having a chamber adapted for communication through a check valve controlled passage with a compressor cylinder and through a port to the atmosphere, a valve opening against fluid pressure in said chamber for controlling said port, a member controlling said latter valve, means for maintaining said latter valve closed, and means for subjecting said member to sub-atmospheric pressure rotluced by said compressor cylinder to e ect movement thereof to open said latter valve when said compressor is unloaded.

14. A compressor unloading mechanism comprising a casing having a chamber adapted for communication with both ends of a compressor cylinder, a check valve adapted to interrupt return flow to each end of said cylinder from said chamber, said chamber having a valve controlled discharge to the atmosphere, said latter valve opening against fluid pressure in said chamber, a member controlling said latter valve, means

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