US1649299A - Compressor - Google Patents

Description

Nav. 15, T927.- 1,649,299

A. D. FERGUSON Nov. T927. 1,649,299

A D.l FERGUSON COMPRESSOR Filed Aug. 11. 1922 2 Sheets-Sheet 2 H/ n a Patented Nov. 15, 1927.

UNiTEo STATES PATENT OFFICE.

ALEXANDER D; FERGUSON, OF CHIGAGO, ILLINOIS, ASSIGNOB T SULLIVAN MACHIN- N EBY COMPANY, A CORPORATION OF MASSACH'USETTS.

l. Y coiiirnnsson.

Application led August 11 1922. Serial No. 581,253.

My invention relates to compressors, and more particularly to compressor systems provided with means `for effecting the progressive unloadin thereof whereby with a` constant speed drive it may be possible for the compressoroutput to be varied in such manner as to `riaintainthe discharge line l pressure within certain desired limits.

the unloading means An object of my invention is to provide an improved compressor mechanism. Another object. o my invention is to providean 'improved compressor mechanism havingv improved partial or step by step unloading means. A further object of my invention is to provide an improved compressor system having improved means for effecting a step by stepunloading of the entire system 'in whi h less of complication is involved than inr such systemspof other types. Other ob- 'ects and advantagesof my invention will ereinafter more fully appear.

In the accompanying drawings -l haveshown for purposes of illustrationV one form which my invention may assume in prac-v In these drawings,-

Fig. 1 is va diagrammatic view of av compressor system provided with the illustrative form` of my invention.

Fig. 2 is a view in central vertical section through the intake unloading means provided for use on the low pressure cylinders of the compressor units, certainlpartsl being shown in elevation.

Fig. 3 is a central vertical section through the pilot mechanism controlling. the operation of my improved system.

Fig. 4J is an, elevation of the saine viewed from a diierent angle.

Fig. 5 is a' transverse section on the line 5-5 of Fig.'3.

Fig. 6 is a detail sectional viewl throughl for one endl of one of the high pressure cylinders.

In the form of my invention shown for purposes of illustration in the accompanyv ing drawings I have shown it embodied in a twin angle compound compressor system which comprises a pair of angle compound discharging compressors 1 and 2, each having low pressure cylinders 3 and high'pressure cylin, ders 4, the low pressure cilinders bein supplied with air lfrom inta e lines 5 an through intercoolers 6 toV the gressive or step by step high pressure cylinders 4 which, in turn, discharge by way of a discharge line 7 to a receiver or other'point of storage or use.

In the customary construction the compressors 1 and 2 are driven romlla common crank shaft 7 more intelligible but in order to permit the disclosure of the piping system employed,.I have shown the compresser units 1 and 2 set .one behind the other instead of in their customary relation. As each of the units is the same in itsgeneral details and as it is by the particular nature of the piping connections lwith the pilot mechanism that the prounloading of the system is accomplished, it will" sutlice if I describe the operative unloading mechanism or one compressor and then describe the control connections and pilot valve for both units. i. L

Accordingly2 consideringy thel compressor unit 1 and noting particularly Fig. 2, it will be observedthat the intake line 5 communicates with a. casing 8 transversely of which there extend partition members 9 and 10, the partition members 9 and 10 being connected at about the longitudinal center of the casing 8 by a vertical partition 11 so that separate 13 are formed and thesechambers 12 and 13 communicate respective-- chambers 12 and by circular ports 15 and 16, which ports are surrounded by valve seats 17 and 18, the ports being identical at each side of the partition 11 and the upper ports being somewhat larger than the vlower to permit the insertion of the'valve mechanism. Slidable through the openings V15 and 16 are valve members which for purposes 'of convenience will 'be designated 20 for the .rear end of the cylinder and 21 for the front end thereof, these valve members each comprising a. pair of circular valve seat portions 22 and 23 which are respectively adapted to seat upon the seats 17 and 18 and from each of the valve seating portions 22 and 23 there depend supported by suitable ribs 24 and 25 guiding portions 26 and 27 which serve to maintain the esY ported through the valve seatymember 52 and so control the discharge of pressure to'la passage59 which communicates with the dis-.

valves 20 and 21 properly centered within their seats during reciprocation thereof. The valves are hollow throughout their length as indicated at 28,' thereby permitting the connection of the chamber 14 with the chamber below the partition 9. Extending ccntrally through the valve members are valve stems 30 which are connected as at 31 to cross arms 32, these latter being in turn connected by springs 33 with cross arms 34 arranged at the top of operating cylinders 35 which are mounted as indicated at 36 upon heads 37 closing the top of the casing 8. Within the cylinders 35 there are pistons 38 reciprocable, these pistons engaging stems 39 connected with the stems 30 and being operative to force the valves 20 or 21, as the case may be, closed on admission of air to their cylinder 35. Suitable stops 42 limit the upward travel of the pistons 38.

For the purpose of greater convenience in subsequent reference to the unloading system as a whole, the unloading mechanism for the front end of the low pressure cylinder of unit No. 1 will be designated generally 43, that for the rear end thereof 44, that for the front end of the Alow pressure cylinder of the unit No. 2 45, and that for its rear end 46.

It will be obvious that' any suitable type of inlet or discharge valves may be employed upon the low pressure cylinders, the mode of operation of my mechanism being absolutel independent of the nature of the valves use On the high pressure cylinders I prefer for reasons which will shortly be apparent to employ a type of combined inlet-and discharge mechanism which is disclosed in the application of one Frank A. Halleck, Serial No. 532,741, tiled Jan. 30, 1922, this mechanism comprising a pair valve seat elements 51 and 52 coaxially arranged with respect to each other and disposed at opposite sides of a port 53 communicating with the end ofthe cylinder bore whereby an annular chamber 54 communieating with the. cylinder bore of the high pressure cylinder is formed between the valve seat members 51 and 52. Suitable annular valves 55 normallyl held closed by transversely flexedspring's 56, which are supby guards' 57, close the ports `58 charge line 7'.l Suitable valves 60 normally vheld closed by transversely y lexed springs '-61-v supported v by a. gna-rd member V62, 'normally maintain passages 63 communicating wit vthe intake lchambers 64 of the high pressure cylinder closed. It will be evident that durf ingthe normal operationof the compressor,

vupon-the suction strokes of thehigh pressure piston, the valve Willbe unseated' by,

intercooler pressure during I the suction of spaced strokes, and that during the discharge strokes the valves 55 will be unseated by the pressure .within the cylinder. One or more of these valve mechanisms may be used at each end of the high pressure cylinders of both the units 1 and 2. Disposed within the intake chambers 64 at thel upper ends of the high pressure cylinders 4 of units 1 and 2, there are mechanisms including valve seat members bolted as at 66 in position upon the tops of the inlet valve cages 51 and each having a port 67 traversing the same, which port is surrounded by a valve seat 68. These mechanisms also each include a` valve member 69 adapted to seat upon the valve seat 68 and formed at the lower end of a piston member 70 which is reciprocable in a cylinder 71 supported on a closure member 72 and projecting through an opening in the upper end of the cylinder head of the cylinder 4. The piston 70 is normally held in raised position with the valve member 69 spaced from the seat 68 by a relatively heavy spring 74 which engages the lower side of the head ofv and the inlet valve shut oil` from all communication with the intercooler while without pressure in the line 75 the valve 69 will stand open and the inlet valve will be free to admit charges of air from the intercooler. To permit the escape of fluid from above the piston 70 any suitable leakage means may be provided, as for example a pin hole 76. These mechanisms or'the units 1 and 2 are respectively designated 81 and 82. Each of the high pressure cylinders 4 is alsoin addition provided with automatic means, herein numbered 85, of the type shown in the patent to H. C. Johansen 1,404,176, Jan. 17, 1922, which is operative to permit the automatic discharge, when the compressor is completely unloaded, of any small leakage past the intake closure valves directly to the tmosphere from the high, pressure cyliners.

.For the purpose of controlling the supply of operating fluid to the receiver pressure operated unloading 'means 43, 44, 45, 46, 81

vand 82, I have devised an improved pilot valve mechanism which I shall now proceed to describe. This pilot valve mechanism --1s generally vdesignated and ,y comprises aspectivelylh 102, 103 and 104, which valve members' are controlled by means which l `shall now more specifically describe. The

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valve members 101 to 104 respectively are arranged to cooperate with .seats 105,' 106, 107, and 108, the several seats being plane and each containing an'annular groove 109, the several annular grooves 109 communicating respectively by passages respectively numbered 110, 111, 112, and 113 with pipes 114, 115, 116 and 117, which pipes I will shortly referto again. Each of the seats to 108 inclusive is traversed by a central passageway, these passageways being of uniform diameter and being indicated at 118. Extending longitudinally through the several passageways mentioned is a stem 120 formed at its top with a plunger or piston 121 upon which a spring 122 housed in the vcasing 123 and adjustable by means of a follower 124 coacts. Formed upon the stem 120 is a collar 125^which is adapted to engage after a predetermined movement from a given lower position which will be more fully described later, the valve member 101 and lift it from its seat 105. Resting upon the top of the valve member 101 is a sleeve 126 which is of slightly less length than the distance between the valve member 101 and the valve member 102 when both are seated. This sleeve is adapted to be raised on upward movement of the valve 101 and after suicient upward movement to engage and lift the valve member 102. A similar sleeve cooperating with the valve 103 in a similar manner and 'designated 127 is superimposed on the valve 102 and a1 further similar sleeve 128 is arranged to be lited by the valve member 103 and to raise the valve member f 104. The piston 121 is slidable in a cylinder 129 Jformed in the casing 123 and fluid pressure from a suitable source. is conducted by a passage 130 to chambers 131, 132, 133, and 134 in which the valve members 101 to 104 respectively are located. This pressure normally tends, of course, to maintain the several valve members seated and as it will be observed that each of the valve Y'members is raised successively alone from its seat and as it will be observed that the valve members are allot substantially equal diameter with the piston 1 1, it willV be apparent that the pressure of air acting beneath the piston 121 is such as to /practically neutralize the work d necessary in raising one of the valve members 0E its seat. The stem 120 asses through a suitable bore 136 downward into a s ace formed between a pair of support mem ers 137 formed integral with a support 138. Secured to the support 138 is an expansible diaphragm chamber 139 to whose interior 140 Huid may be conducted by a passage 141 and a series of grooves 142 formed in a-member 143 which threadedly 'engages the lower head 144 of the diaphragm chamber and l holds-it tixedly in position on the member 138. The member 143 istraversed by a passage 145 through which a plunger 146, alined with'the stem-120 and having suitable sealing grooves 147 snugly extends, the plunger 146 engaging at 148 the upper-'head 149 of thediaphragmchamber. The plunger 146 is provided at its lower end with a handle 150 and is traversed by a series of four parallel transverse passageways 151, ,152, 153,

` and 154. The member 143 is provided with seated and as each successive pair of holes is brought into register an additional valve is opened. The function of this mechanism will shortly be explained.

Leading from a receiver pressors discharge, or from their common discharge line, is a passage or connection controlled by a stop valve 161 and provided with a strainer 162 to prevent the passage ofimpurities or solid matter to the valve mechanism. Beyond the strainer 162 is a T 163 from which a connection 164 leadsto the passageway 130 previously described. From -the other end of the T a connection 165 leads to the pop valve 166 which pop valve. works on the principle of the ordinary safety valve, that is, it opens when a desired pressure is reached in the line 160' and permitsy a pressure equal to the excess the desired pressure in line 160 to pass 4through the valve before it again closes.

The chamber above the valve in the pop valve 166 communicates with the passage 1'41 so that a pressure equal to the excess above the seating of the pop valve will be transmitted to the diaphragm chamber 140. Upon the top of the pop valve 166 is a safety valve 167 loaded to prevent building up of' more than a desired ressure in the diaphragm chamber 140. hole leak or adjustable leak 166 as may be desired' is arranged at any suitable point between the pop valve 166 and the 'limits of the diaphragm chamber whereby the pressure in the chamber 140 will promptly fall' on closure of the pop valve 166; Leakage may also to which the combe permitted aroundthe plunger" lill) above lll) suitable pin.

146,41. shoulder 168 thereon then cooperat-,

ing with the top of the member 143 in preventing leakage whenthe diaphragm is collapsed to its smallest size. j

It will be recalled that a seriesA of pipes 114, 115, 116, and 117 have been described above; These pipes are connected to the several unloading means 43, 44, 45, 46, 81 and`vv 82 as follows: The pipe 114 connects by.

branches 17.5 and 176 respectively to the low, pressure intake closure typ-e unloading means 44 and the high pressure unloading means 81 of unit No. 1, the pipe 115 connects vto the vother low pressure unloading means 43 of vunit No. 1. Pipe 116 connects -by suitable branches 177 and 178 respectively to the low pressure unloading means 46 and the high pressure unloading means 82 of unit No. 2, while the passage 117 connects to the second'low pressure'unloading means 45 of unit No. 2.

` From the description of the mechanism itself, the mode of operation of this invention will already be apparent,'but it may be briefly summarized as follows: Let. it be assumed that the compressor is supplying air to a plant in which the demand for air is such as to cause the compressor to operate at full load to maintain the necessary supply line pressure'. .Now let it be assumed that the demand for air falls off slightly. As a result, since the compressor is being driven at a constant speed, the pressure in the compressor discharge line, i. e. the supply line tothe plant, will rise and as aD result the pop valve 166 which is set to open when the pressure exceeds the desired line/pres# su-re, say 100 pounds, will open and pressure will be transmitted into the diaphragm chamber 140. 'If the pressure rises to a value say two or three pounds in excess of the desired 100 pounds, `the expansion of the diaphragm chamber will cause the collar 125 t\o raise the valve 101 and pressure will be supplied to the line 114. As a result, air will be supplied to close the intake to the head end ofthe low pressure cylinder and to the head end of the high pressure cylinder, this being accomplished by means of the unloading mechanisms 44 and 81, and the-compressor system will then operate at three-quarter load, unit No. 2 continuing to'operate at full load and unit No. 1 acting as a compressor havin@ single acting high and low pressure .cylin ers. It the demand for air fallsv off sufficiently to cause the pressure to reach a value a few pounds higher than was necessary to open valve 101, valve 102 will be raised by continued up- Ward movement of valve 101, causing the sleeve 118 to lift valve 102. Pressure will then be transmitted through pipe 115 to' unloading means 43and the intake to the crank end of low pressure cylinder ofunit No. 1 will also be closed. Unit No. 1 will then be completely unloaded since no air except a small yquantity which may leak in can secure admission to the compressor. The small quantity of air which may leak past the `closed intake controlling valves 20 and 21 orwhich may leak in through the packings around the piston rods, etc., will be discharged direct to the atmosphere by the automatic means 85 previously described. If the pressure in the discharge line rises still further, the valve 103 will be opened and pressure supplied through pipe 116 to close the connections between the head ends of the low and high pressure cylinders of unit No. 2 and the points of suction of these cylinders, that is, the low pressure cylinder can no longer draw in air from the atmosphere and the high pressure cylinder canno longer draw in air from the intercooler, as to their head ends respectively. It the demand falls oil' still further or ceases entirely, the valve 104 will finally be opened and transmission of pressure through line 117 to the unloading means 45 will completely unload unit No. 2. As the demand for air increases, the compressor units will be progressively reloaded l in an obvious manner as the valves 104, 103,

102, and 101 are successively closed.

In case the demand for air over a long period is less than the capacity of the com pressor, the handle 150 may be forced upward and by the insertion of a suitable pin through the holes 151 and 159 the compressors maximum output may be reduced to three-quarters of its potential output, or byinserting the pin in other pairs of mating holes, other still smaller maximum capacities may be obtained. y vWhile I have in this application specilical-` ly described one form which my invention may assume in practice, it will be understood that this form of the same is shown for purposes of yillustration and that the invention may be modified and embodied in 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 pumping unit, in combination, a compound pump havingdouble acting high and low pressure cylinders each provided with suitable inlet and discharge valves, means for closing olf communication between the inlet valves atv one end of both the high and .low pressure cylinders and their respective supply spaces,l means for closing the V...intake to the other end of said lowpressure cylinder, pump discharge pressure controlled means controlling said first and second mentioned means, and relief valve means for venting said high pressure cylinder.

2. In a pumping system, a pair of compound pumps each )having double acting.

high and low pressure cylinders which are provided with suitable inlet and discharge valves, means for unloading said pumps comprising intake closure means for one end of both the high and the low pressure cylinders of one of said pumps, intake closure means for the other end of the low pressure cylinder of said pump, similar unloading means for the secondl pump, pump discharge pressure controlled means for controlling serially i ally disposed inlet and of said pumps.

said several unloading means, and automatic relief means for the high pressure c linders 3. In a compressor, in combination, an inlet valve, a yalveseat therefor, and 1ntake closure means including a valve coaxlally arranged with respect thereto and movable rectilinearly axially thereof, and a valve seat cooperating with said second valve, said seat being disposed parallel to said first seat.`

4. In a compressor, in combination, coaxidischarge valves, and intake closure means coaxially arranged with respect thereto.

5. In a compressor,

with adapted to control flow' of fluid to said inlet valve, and a cylinder and piston coaxially arranged with respect to said valves for operating said intake closure valve.

6. In combination with coaxially arranged inlet and discharge valve mechanism for a high pressure cylinder having a head, of intake closure means coaxially arranged With espdect to said inlet valveV disposed in said ea v 7. In a compressor, 1n combination, an iniet valve, a cage therefor, and a -cover fork controlling How of fluid through said cage, and actuating means through which said controlis effected including a cylinder and piston coaxially arranged with respect to said inlet valve.

8. In combination with a compressor inlet and exhaust valve mechanism, of intake closure means coaxially arranged with respect thereto, and actuating means therefor, said closure means constituting an element of said actuating means.

9. In a compressor system including a plurality of pumping units cooperating in delivering air to a common control means for controlling the latter operative to cause successive unloading of said units and including means for manually shutting down certain of said units.

10. In a compressor system vincluding a plurality of pumping units cooperating i'n delivering air to a common discharge line, unloading means for each unit, and common control means for controlling the latter oper- ,A

ative to cause successive unloadingof said umts and including means for,1 manually shuttlng down certain of said units, While leaving the. remaining .units under the autop operable matic control of said-controlling means.

11. -In a pumping mechanism, a plurality of pumpin units, common controlling lmeanstherefor adapted to control said units serially automatically, and manually operable means adjustable to remove certain of said units from automatic 12. In a pumpingmechanlsm,

in combination, an inlet valve, avalve disposed coaxlally theredischarge line, unloading means for each unit, and common control While ,leaving the remainder subject thereto.

` a plurality I of lpumping units, common vcontrolling means therefor adapted to control said units serially automatically,'and manuallyl operable means adjustable to remove certain of said units vfrom automatic control While leaving the remainder subject thereto and under identical controlling conditions.

13. In a pumping mechanism, a plurality ofy pumping units, commonv controlling means therefor adapted to interrupt the pumping operation of said units at different predetermined pressures, and manually operable means adjustable to remove certain of said .units from automatic control While leaving the remainder subject thereto.

14. In a pumping mechanism, a-plurality of4 pumping units, common controlling means therefor adapted' to interrupt the pumping operation of said units at different predetermined pressures, and manually operable means adjustable to remove certain of said units from automatic control While leaving the remainder subject thereto at the same pressure conditions as when all are automatically controlled.

15. In a pumping mechanism, of pumping units, common means therefor adapted to control said units serially automatically, and manually operable means adapted to act upon the automatic means and adjustable to remove certainof said units from automatic control whileleaving the remainder subject thereto.

16. In a 'pumping mechanism, a plurality of pumping units, common controlling means therefor adapted to control said units serially able means adapted to act ,upon the automatic means and adjustable to remove ce1;- tain of said units from automatic control While leaving the remainder subject thereto and under identical controlling conditions. 17. In a pumping mechanism, a plurality common controlling to interrupt Athe a plurality of pumping units, means therefor adapted .pumping operation of said units at different and 'manually predetermined pressures,

to act upon the operable means adapted automatic means and adjustable to remove certain of said units from automatic control while leaving the remaindery subject thereto.

A18. In a pumping mechanism, a plurality of pumping units, common controlling means therefor "adapted to interrupt the pumping operation of said units at different redetermined pressures, and manually automatic 'certain of said;l units from automatic control While leaving the remainder subject-thereto at the same pressure" conditions as when all are automatically controlled.

In testimony whereof I aiiix'mysignature.

ALEXANDER D. FERGUSON.

automatically, and manually opercontrolling means adapted to act Lupon the means vand adjustable to remove-

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