US1968864A - Pump controlling apparatus - Google Patents

Description

ug.v7, 1934. w; H. WINEMAN PUMP CONTROLLI NG APPARATUS Filed Dec.

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n.. :E Q i PatentedAug. 7, 1934 UNITED SrArss ,rerrNr--orrics Wade n. wineman, Michigan camine.; assigner f to SullivanvMachiner-y Company, a corporation, v H

' Application Decanter` 217, 1929, serial m4111014 l11 claims. (01.23097) This invention relates to pressure switch `mechanism@ `More particularly, .this invention relates to mechanism for controlling .now .of actuating medium to a compressor unloading 1, `:i meansw 4 N V One objectgof my invention is to provide a pressure` switch mechanism so constructed as .to` control 'a circuit in .which a` heavy current may flow, employing a pressure responsive means .1: and means including a pair of electric circuits controlled by the pressure responsive means for making and breaking the main circuit. A furtherobject` of my .invention is` to provide such a; pressure switch mechanism Vin which a 1 5 light currentis suiiicient to actuate themeans Whichfvmake and break- Vthe mainzzcircuit.; .A still41 further object of my inventionis to provide a pressure switch `mechanism having `a main circuitincluding a movable member for break-V l2Q ingthe circuitgan'd meansjfor controlling move.-

ment thereof `including solenoids which carry current only for short periods; rA stilljfurther objectrof my inventionpis to provide mechanism for* controlling flow of actuating mediurnto a 1525 compressorV unloading means comprising an electrical' deviceV adapted when actuated, to permit flow of actuating medium to the unloading means, a main circuit for supplying thercurrent ,tosaid electrical device, and means requiring ``3 0 but `a small amount `of current for controlling the movablemember which makes andbreaks the main circuit. Further. objectsof my in-` vention will become apparent inthe courseof the ensuing description and willbe particularly .35 pointed. out inthe accompanying claims.

u In .one form, my invention may comprise `a main circuit including a movable switch member Vfor making and breaking the same, together with means for controlling movement ofthe 4v4to movable switchl memberincluding a movable contact'which` moves to dilerent `positions as the' pressureqof the controlling fluid changes, an electric circuit having a contact in position to be engaged by the contact memberiwhen a KLii'wpredetermined relatively higher pressure occurs in the controlling fluid, said circuit supplying current for moving the switch member 'inone directiom 'and a 'circuit having a contact in position tobe engagedv by the contact member 501 when a predetermined relatively lower pressure occurs in the controlling fluid; said last mentioned circuit supplying current for moving the switch member in anotherl direction. v'

` 55 For purposes of illustration oneembodiment which my invention may assume is disclosed in the accompanying-drawing, in which,-`

Fig. 1 isa View in sideselevation of a compressor driven by anelectric motor and providedfwith unloading mechanism to which pressure iiuid is supplied' under the control of` a pressure` switch embodying my inventiony Fig. 2 is a diagrammatic -view of such apressurelswitch, together with a wiring diagram il. lustrating-the connections to a valve for` con- 6 trolling flow of pressurerfluidrto :the unloading mechanismshown inFig. 1 and t 1 1 Flg.-3fis an enlarged, fragmentary view,A partially in sectioni showing; details of construction. ,The compressormechanism shown1 in Fig.1 iris ofv thecornpound vvtype having a llow pressure cylinder 6" extending horizontally fromv a base ramel. v The fluid` is'pumped through an intercooler intoa high pressure cylinder 9. 'Dis-1 charge from the compressor takes places through a'conduit 10 intozanreceiver 11.1' An` electric motor l-zisoperatively connected tofthe ily wheel-13` of the compressor for driving the same. Unloading mechanism 4l5-of the complete closure `typeV cooperates with the inlet 16 ofthe low pressure cylinder to prevent air entering the low pressure cylinder when it is desired to unload Y the compressor. A servo-motor 17 is connected by pipe 18 to thereceiver V11A lsothat' pressure fluid maylow from" the latter to the `servomotor 17 to .1 actuate the same;` VA three-way valve mechanism .19j `controls flow offluid through.the pipe l18. ,1 1 Thisvalve mechanismrlQ includes a chamber 2Q1closed by athreadecl'plug 21', and a vent 22 controlled.V by avalve 231which cooperates` with a valveseatzlV surrounding the vent 22. The stem or" thevalve 2.3 is shown-hereinA as integral with 4the stemiof a yvalve 26 which co4 operates-with the valve seat V2'lrto control 110WY oi fluid `fromvthe `chamber. 20 into a bore 28: Obviously .unless-.1a divided casing :were to be used, separate end-abutting stemsv for valves 23 and 26 would be used. spring 29 guided by. a pin 30 supported by the-plug' 21 biases Vthe valves .23 and 26 into `position or closing ,the passage between the chamber 20 andthe bore; 28'. Arbore 31 is formed inthe outer-end of .the valve126 toyreceive the adjacent end olf :fthe springv29. A spring 32 similarly cooperates with the valve 23 abutting at Aits outer end against aY head Y33 on the .core` 34` oasolenoid 35. 1 A stiffV coil springV 36 `surrounds the core 34 and tendsto `force the core Bfl toward the valve 23 to-V close the vent 22. The ,valve mechanism-19 is interposed between two sections of the pipe 18, one section being threadedly connected with the casing of the valve mechanism 19 so as to communicate with the bore 28 and the other section being threadedly connected with the casing of the mechanism 19 so as to communicate with the chamber 20.

When the solenoid 35 is deenergized, the stii spring 36 which must be powerful enough to overcome any receiver pressure which will ordinarily occur, forces the valve 26 off its seat and closes the vent 22 by forcing the valve 23 against its seat 24. Fluid under pressure now ows from the receiver 11 through pipe 18 to the servo-motor 17 to unload the compressor. If the solenoid 35 be actuated, the spring 36 will be compressed and valve 26 will engage its seat 27 to prevent further supply of fluid from the receiver 11 while at the same time the vent 22 will be open to permit the servo-motor 17 to be vented so that the compressor may run loaded.

It is obvious that, if desired, the spring 36 may be reversed in its operations so as to normally bias the head 33 away from valve seat 24. If this change be made, the direction in which the solenoid 35 acts will be reversed. Under these conditions, the unloading mechanism will be altered so as to unload the compressor whenever the servo-motor 17 is vented. The operation of such a device will be as follows. When the solenoid is deenergized, communication between the two sections of the pipe 18 is cut ofi and the servo-motor is vented so that the compressor is unloaded. If the solenoid 35 be now energized, the vent 22 will be closed and the pressure uid will be supplied througfh pipe 18. from the receiver 11 to the servo-motor 17 so as to load the compressor. Such an arrangement will call for appropriate design of the control circuits.

A switch 38 whose contacts are adapted to break the flow of a substantially heavy current is mounted in a box or casing 39 and connected in the circuit to which current is supplied from the main leads 40, 41 for energizing the solenoid 35. One of the contacts 42 is supported by the casing 39 and the other, 43, is carried by the depending arm 44 of a bell crank lever which is pivoted at 45 to the casing 39. The depending arm 44 constitutes a switch member carrying the contact 43. The other arm 47 of the bell crank lever carries at its outer end a lower contact 48 which is secured to the lower face of the arm 47 and a contact 49 which covers the end of the arm 47. A circuit which is connected to the lead 40 includes a line 50, a pointer 51 of a pressure gauge 52, a contact 53, a line 54, a solenoid 55, and a line 56 which extends along the arm 47 and is connected to the contact 48. This circuit continues through a contact 57 which is carried on a pivoted arm 58 pivoted at 59 to the casing 49. The circuit is completed to the main lead 41 through a line 60. A second circuit includes the line 50, the pointer 51, a

j contact 61, a line 62, a solenoid 63 and a line 64 which extendsalong the ar m47 and is connected to the contact 49. This circuit is completed through the contact 57 and the line 60.

The operation of my improved pressure switch is as follows. The pressure gauge 52 is connected to the receiver tank 11. Should the valve mechanism 19 be in the condition shown in Fig. 2, thecompressor will be loaded, since the circuit from the leads 40, 41 through the switch 38 is complete. If the pressure in the receiver should rise sufficiently to bring the pointer 51 into contact with the contact 53, the circuit through the solenoid 55 and wire 56 is completed by way of contacts 48 and 57. The energizing solenoid 55 quickly moves the pivoted arm 58 to the left so that the bell crank lever may drop, breaking the circuit through the solenoid 35 at switch 38. The contact 57 comes into engagement with the Contact 49 which is on the end of the arm 47, and the arm 47 and contact 49 operate as a latch to hold the arm 58 against return to its vertical position by the spring 65, so that the pivoted arm 58 is held in canted position even though the solenoid 55 is at once deenergized by the breaking of the circuit through wire 56, contact 48 and Contact 57. The solenoid 35 is now deenergized and the compressor unloaded until the pressure drops low enough so that the pointer 51 comes in contact with the contact 61.

When the pointer 51 completes the second circuit by contacting with the contact 61, the solenoid 63 is energized to elevate the arm 47, thereby bringing the contact 43 against the contact 42. It will be noted that movement of the arm 47 into raised position permits the contact 57 to be moved by the compression spring 65 beneath the outer end of the arm into supporting relation therewith. It is obvious that closing of the switch 38 immediately energizes the solenoid 35 to load the compressor by moving the valve 23 away from the seat 24 to open the vent 22, and also seating valve 25 to interrupt pressure supply to the servo-motor 17. The

Contact 49 is moved away from the contact 57 i;

and accordingly the circuit through the solenoid 63 is broken and the same is deenergized. Both the contact 48 and the contact 49 are insulated from the arm 47 and from each other. It will furthermore be noted that there is a gap between contact 48 and contact 49 which is of advantage when a circuit is to be broken by movement of the contact 57 from engagement with contact 43 or movement of contact 49 from engagement with contact 57. furthermore be noted that neither solenoid 63 nor solenoid 55 is energized for a long period 0f time, since the circuit through each solenoid is broken by movement of the member actuated by the respective solenoid. It is obvious therefore that my pressure switch has the advantage of using no current during periods when the compressor runs unloaded, or, when the compressor runs loaded, except such current as is used in the solenoid 35. It will furthermore be noted that only a small amount of current needs to pass through the'pointer 51 as the current which actuates the device for supplying or venting actuating medium to the compressor unloader liows through leads 4l and 40 by way 1 of switch 38. By introducing sufficient resistance in the circuits to the solenoids 55 and 63 the current owing through the same may be cut down to an amount just sufficient to actuate these solenoids. Moreover, the pointer f does not move out of engagement with either contact 61 or contact 53 while current is nowing through the same. This results because the current through both solenoid 55 and solenoid 63 is interrupted as soon as the pivoted member 1:."

58 or the bell crank lever 56 has been moved. Because of this fact, there is no tendency to fuse the point of the pointer 51 to either contact 53 or contact 61 by the formation of an arc therebetween.

It should 1:'

incassi 3 fWhile there isf in this application sp'ecilcally fdesoribed Aone `form 'which the invention may assumednpractica it will be understood that this form of the same 'is shown for purposes Tcf illustration and that the invention may be modifiedv and embodied in various other forms without departing irom its'spirit Vor the scope Oi`the`appended claims. I V"What- I Vclaimas new and desire to secure by Letters" Patent isi:

combination, a compressor, means for driving the same, said compressorl havingv unloading means ofthe -fluid actuated type, and means for `alternatively supplying and venting `operating medium to vsaid'unloading means to "control the-output of the compressor while the `same is "driven continuously including valve means, Vand anv electrical device adapted when actuated to" move said valve means to control 'flcwoi actuating medium, a main circuit for the actuating current for said electrical device, said main circuit including a movable member for breaking the same, and means for controlling movements of said member including an upper limit solenoid and a lower limit solenoid, means for completing a circult through said upper limit solenoid. when a predetermined maximum compressor discharge pressure is attained, and means for completing a circuit through said lower limit solenoid when a predetermined minimum pressure is reached by ,the compressor discharge pressure, the circuit through one of said solenoids being bro-ken by movement oi said movable member in response to energization of one of the solenoids.

2. In combination, a compressor, means for driving the same, said compressor having unloading means oi the i'luid actuated type, and means for alternatively supplying and venting operating medium to said unloading means to control the output of the com ressor while the same is driven continuously including valve means, and an electrical device adapted when actuated to move said valve means to control flow of actuating medium, a main circuit for the actuating current for said electrical device, said main circuit including a movable member for breaking the same, and means for controlling movements of said member including an upper limit solenoid and a lower limit solenoid, means for completing a circuit through said upper limit solenoid when a predetermined maximum compressor discharge pressure is attained, and means for completing a circuit throughsaid lower limit solenoid when a predetermined minimum pressure is reached by the compressor discharge pressure, the circuit through each of said solenoids being broken by movement of said movable member in response to energization of the solenoids.

3. In combination, a compressor, driving means therefor, and means for controlling the output of the compressor in accordance with the discharge pressure thereof during continuous driving of said compressor including pressure actuated unloading means and controlling means thereior for controlling the flow of actuating medium relative thereto including a valve mechanism and an electrical controlling device therefor adapted when actuated to cause said valve mechanism to control flow of actuating medium, a main circuit for the actuating current for said electrical device, said main circuit having a movable member for breaking the same, and means including a secondary circuit for controlling saidmain circuit operable withasmaller amount'of current than"'=fl`ows through said main circuit.

4."`In 'combir1ation,"'a compressor, vdriving 1means therefor, andmans 'for controlling the output of the compressor in accordance with the discharge pressure thereof during continuous driving oi said compressor including pressure actuated unloading means and controlling Ameans therefor for controlling the ow of? actuating medium relative'thereto including a-valve mechanism and Aan electricalcontrolling device therefor adapted when `actuated to cause said 4valve mechansm to control flow of actuating medium, a main circuit for4 the actuating-.cur-

rent for said electrical device, said main fcircuit `including a movable member for breakingthe saine, andfmeans forv controlling said man'circuit including, a secondary dircuit `having a 'solenoid therein of high resistance wherebyv a 'smaller current is used in said secondary circuit than flows thrOughsaid main circuit.

5. In combination, a i compressor', driving means therefor, and means for controlling the output of the compressor in accordance with the discharge pressure thereof during continuous driving of said compressor including pressure actuated unloading means and controlling Teo means therefor for controlling the flow of actuv ating medium relative thereto including a valve mechanism and an electrical controlling device therefor adapted when actuated to cause said valve mechanism to control flow of actuating medium, a main circuit for the actuating current for said electrical device, said main circuit including a movable member for'breaking the same, and means including a secondary circuit having a solenoid operated element, for controlling said main circuit, said solenoid circuit and main circuit being supplied from a common source and the resistance of the respective circuits being such that a relatively large current flows through the main circuit` and a relatively small current through the secondary circuit.

6. In combination, a compressor, driving means therefor, said compressor having unloading means and means for operating said unloading means to load and unload the compressor during continuous driving thereof including an electrical device for controlling the unloading operation, a main circuit for actuating said device, a secondary circuit for controlling said main circuit, and means whereby said secondary circuit is energized only momentarily while controlling said main circuit.

7. In a pressure responsive control mechanism, a controlling device normally biased toward one position, means including a solenoid for moving said controlling device to its opposite position, latch means for holding the controlling device in the last mentioned position automatically when it reaches the same, means including a solenoid for releasing said latch means, and means for energizing said solenoids separately including switch means responsive to a pressure to be controlled.

8. In a pressure responsive control mechanism, a switch member carrying a contact and normally biased toward one position, means including a solenoid for moving said switch member to its opposite position, latch means for holding the switch member in the last mentioned position automatically when it reaches the same, means including a solenoid for releasing said ilo latch means, and means for energizing said solenoids separately including switch means responsive to a pressure to be controlled.

9. In a pressure responsive control mechanism, a switch member carrying a Contact and normally biased toward one position, means including a so-lenoid for moving said switch inember to its opposite position, latch means for holding the switch member in the last mentioned position automatically when it reaches the same, means including a solenoid for releasing said latch means, and means for energizing said solenoids separately including switch means responsive to a pressure to be controlled and switch elements movable with said latch means and said switch member.

10. In a pressure responsive control mechanism, a switch member carrying a contact and normally biased toward one position, means including a `solenoid for moving said switch member to its opposite position, latch means for holding the switch member in the last mentioned position automatically when it reaches the same,

means including a solenoid for releasing said latch means, and means for energizing said solenoids separately including switch means responsive to a pressure to be controlled and means for precluding the breaking of live circuits at said last mentioned switch means.

11. In a pressure responsive control mechanism, a switch member carrying a Contact and normally biased toward one position, means including a solenoid for moving said switch memloer to its opposite position, latch means for holding the switch member in the last mentioned position automatically when it reaches the same, means including a solenoid for releasing said latch means, and means for enerizing said solenoids separately including switch means responsive to a pressure to be controlled and means for precluding the breaking of live circuits at said last mentioned switch means including switch elements respectively moved by said` solenoids.

WADE H. WINEMAN.

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