US2134693A - Pumping mechanism - Google Patents

Description

Nov. 1, 1938. .1. M. BAR-THOLOM-EW PUMPING MECHANISM Filed July 16, 1936 fizventbr: h dw'flfiarfalamem a Aw 1 mm,

Patented Nov. 1-, 1938 UNITED STATES PATENT OFFICE,

PUMPING MECHANISM Jess M. Bartholomew, Michigan City, Ind., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application July 16, 1936, Serial No. 90,946 15 Claims. (01. 230-24) My invention relates to an improved automatic system for controlling the starting and operation of a motor driven compressor.

It is desirable in the operation of motor driven compressors, particularly where a fairly constant and high demand for air exists, to operate the compressor on the continuous-drive, load-andunload system of output control. It is also desirable to control the compressor during starting in such manner that the compressor shall start unloaded. It-is further desirable to use the simplest possible controlling equipment to accomplish the functions mentioned. These same principles of course apply to pumps handling other fluids than air where the conditions are generally the same, and it is perhaps even more important to provide for starting of a hydraulic pump unloaded than is the case with compressors tor gaseous fluids. P

It is an object of my invention to provide an improved compressor controllmgapparatus. .It is another object of my invention to provide an improved compressor controlling apparatus operating to control the volume of fluid pumped by loading and unloading, while drive is maintained.

It is 'a. further object of my invention to provide an improved. pumping system having improved means for effecting unloading during starting, as

well as unloaded operation when a predetermined excess of fluid is pumped. Other objects and advantages of the invention will hereinaiter more fully appear.

In the accompanying drawing I have shown for purposes of illustration one embodiment which my invention may assume in practice.

In this drawing,

Fig. l is a diagrammatic view of a compressor outfit having associated therewith an illustrative embodiment of my improved controlling mechanism.

Fig. 2 is a fragmentary view showing a section through an electrically controlled pilot mechanism and through the valve mechanismand associated unloading device for a compressor cylinder.

Referring first to Fig. 1, it will noted. that a motor I drives a compressor 2, herein or the ver-- tical two-cylinder type. The compressor discharges fluid through the branch lines 3, 3 to a discharge line 4. which delivers to a receiver 5, from which the pumped fluid may be led away to a point of use through a connection 6. Current for operating the motor i is supplied from lines L, W and L4. and tha motor i is herein of the three-phase type. A multi-pole switch I having port it controllable by a valve 44.

concurrently movable contact elements I l I 2, and Ill respectively controlling current flow from the lines L ii. and L is arranged to control the supply to the motor leads M M and M and overload coils O and 0 are arranged in the 5 motor leads M and M A plunger l 4 is arranged in position to be raised by a solenoid l5 upon energization of the latter to close the multi-pole switch 1 and effect motor starting. The overload coils O and 0 have re- 10 spectively associated with them plungers 0 and 0" arranged so that either or both may actuate an appropriate overload controlled switch It.

The compressor cylinders I1 and 18 are each. provided with individual inlet and discharge 15 valves, and Fig. 2 shows the inlet and discharge valve mechanism and associated unloading mechanism for one oi the compressor cylinders. A passage 20 opens into the outer end of one of the compressor cylinders. An inlet valve mech- 80 anism 2| controls the admission of air to the cylinder through the port 20. A discharge valve mechanism 22 controls the discharge of air through the port 20 and to a space 23 communicating with one of the branch discharge lines 5. 25 A plunger 24 movable in a cylinder 25, and normally maintained in its outer position by a spring 2'6, actuates a fork-like member 21 whose prongs 28 pass through the port openings 29 in the inlet valve mechanism into engagement with the inlet 80 valve proper 30, and'open the latter and hold the latter unseated, that is, in unloading position, when air is admitted to the outer end oi the cylinder 25. Supply of air to the cylinder 25 is controlled by an electrically operated pilot mechas anism 32 which receives a supply of operating pressure through a line 33 leading from the receiver 5 and controls the delivery of that operating pressure through a line 14 to the cylinders 25. This pilot mechanism also controls the vent- {0 ing of pressure from theline 34 and cylinders 25 to a point of escape, as at 55. g

The pilot mechanism comprises a casing 31 having a vent chamber 38, a chamber 39 communicating with the cylinder 25, anda supply 45 chamber 40. Chambers 38 and 38 are connectible through a valve-seatisurrounded port 4| controlled bya valve .42, and chambers 39 and 4|! are connectible through a valve-seat-surrounded Valves 42 5c and M are so related that but one can be seated at a time. Springs 45 and 45 normally tend to close each of the valves whenever its closure is possible. By the provision of arelativel'y heavy plunger 48 operatively connected with the valves the interlock switch element 8i coacts in estab-,

42 and 44, the valve 44 may be maintained open -on the other hand, plunger 48 is raised, valve 44 closes port 48 and valve 42 opens port 4|, and

accordingly no more air is supplied to the 'cyl-' inder 28,'but instead the latter is vented through connection 84, chamber 89, passage 4|, chamber 88 and port 88 to the atmosphere. To raise the plunger 48 when'desired, a magnetwinding 58 is arranged in proper relation to the plunger so that upon the supply of current to the magnet winding 58, the same will be energized and effective to lift the plunger 48 -and',cause a reversal of the position of the valves shown in Fig. 2. It will be noted that the pilotmechanism 32 will effect unloading'when the. solenoid or magnet 88 is de-energized, .and loading when it is energized, and so that energization and de-energization of the magnet '58 may becaused to take place in proper dependence upon the receiver pressure, means is provided including a pressure responsive switch 82 having herein a pressure responsive element 58 subjected at one side 'to receiver pressure through -a connection 84 and having its other side adapted to transmit motion to a switch element 88 through a suitable mechanism, herein a bell crank mechanism 56.

Before further describing the circuits of the illustrative embodiment of the invention I may state that I provide a starting switch mechanism, generally designated START, and a stopping switch mechanism, generally designated STOP, and that with the starting switch mechanism there is herein associated a time delay device 88 whose purpose and structure will later be de-- scribed. It may be noted also that at 8| there is provided an auxiliary switch element of the so-called interlock type whose purpose will shortly be apparent, this switch element being moved to closed position concurrently with the closure oi the starting switch 1.

- Now it will be noted that a conductor 82 leads from-the motor lead M? to one end of the magnet winding 88, and that the other end 01 this magnetw'indingis connected by a conductor 88 to one of the stationary contact elements 64 asso; ciated with the receiver-pressure-operated switch element 88. ,The other stationary contact 88, with which the switch element 55 coacts, is connected by a conductor 88 to a contact 81 forming one of an upper pair (the other numbercd 88) of contacts of the START switch apparatus. A movable contact member 88 in its upper position is adapted to connect the contacts 81, 88. Contact 88 is connected by a conductor 18 and a conductor H to line L and by a-conductor 12 is connected both to a conductor 18 leading to a stationary contact 14 with which iishing a circuit later more fully described, and also by a conductor 18 to a lower stationary contact 18 forming one of a pair (the other element is numbered 11) of lower contacts of the START switch mechanism. Contact element 11 is connected by a conductor 18 to an upper contact 19 engageable in its closed position by the switch element 88 of the STOP switch mechanism. The other stationary contact of the STOP switch mechanism, designated 8|, is connected by a conductor 82 to the pivot end of the interlock switch 8i. From theconductor 18 there branches a conductor 83 which leads to one end of the main operating coil l for the starting switch, and the other end of said operating magnet coil is connected by a conductor 84 to a stationary contact 85 with which switch element l8 'coacts. The other stationary contact 86 with which switch element l6 contacts is connected by a conductor 81 toline L. A spring 88 normally maintains the STOP switch element 88 in contact with stationary contacts 19, 8|. A spring 89 normally maintains the switch element 69 in contact with the contacts 81, 88. A manually operablev plunger 98 may be moved downward through means including the dashpot mechanism 68 against the pressure of the spring 89 with substantially no retardation, and cause 69 to connect contact elements 16, 11. The dashpot device 68 provides a slow, retarded, upward movement of the switch element 69 with a substantial time delay after pressure is removed from the plunger 98 before contact will be broken between the element 69 and the contacts 18 and 11. The by-pass 9i permits a sharp upward movement of the switch element 68 just as it approaches the point of leaving contact with the stationary switch elements 18, 11, so that arcing is minimized.

Now, the mode of operation of this device will be readily understood, but as a preliminary, it should be said that the time delay created by the dashpot device 88 will be made such that the motor I will have had abundant time to bring the compressor 2 up to full operating speed before, even following an immediate release of pressure from the plunger 98, the switch element 89 will be able to leave contact with the stationary switch elements 16 and 11.

To start the compressor, the operator will depress the plunger 98 and move the contact ele* ment 69 into contact with the elements 18 and 11. This will establish a circuit from line L through conductor 81, switch 86, I8, 85,conductor 84, magnet winding l5, conductor 83, conductor 18, switch 11, 89, 18, and conductor 15, conductor 12 and conductor 1| to line L This will energize the magnet winding l5, and'the plunger l4 will close the switch 1 and move the interlock switch element 8| into contact with the stationary contact element 14. Closure of the switch element 6| will result in a circuit from line B through conductor 81, switch 88, I8, 85, conductor 84, magnet" l5, conductor 83, the stop switch 19, 88, 8!, conductor 82, switch element 8i, stationary switch contact 14, and conductors 18, 12, 1| to line L this being in parallel to the circuit originally established; and accordingly, even through the spring 89, after a few seconds of initial supply of motor starting current, moves the contact 89 to break the circuit between contacts 16, 11, there will be maintained an energizationbi the solenoid l8 and a maintenance of the switch 1 in closed position. It will be noted that this holding circuit includes the STOP switch mechanism, and that by depressing the member 88 out of contact with the contacts 18, 8t, the solenoid l5 can be readily de-energized and the motor caused to stop by the opening of the starting switch 1'. Itwill be noted, moreover, that upon an overload of the motor, the

excessive flow 01' current through either coil 0 or or both. will be effective to cause opening of the switch I, and this also will break .the

circuit through the main motor switch operating interlock switch element 8| also moves to open position, and so manual closure of the starting switch mechanism, including the downward movement of the plunger 98 and the switch eiement 88, the latter into contact with the contacts T6 and TI, is necessary to restart the motor.

It will be observed that the depressing o! the element 69 out of engagement with the contacts 61 and 68 prevents the establishment of a circult, which would otherwise have been made on closure of the switch element ii, if the pressure was low enough tocause switch 58 to close, from line L throughswitch element 12, motor lead M", conductor 62, magnet winding 50, conductor 88, contact 64, switch element 55. contact 65,

conductor 66, contact 81, switch element 69, contact 68, conductor 18, conductor H, and line L Accordingly, energization of the winding 58 is impossible until switch element 68 moves back a into contact with the contacts 61, 68, and therefore, because of the time delay device, loading will be impossible until the motor has come up to speed, the time lapse occasioned by the dashpot mechanism 68 giving time enough for this to result. Obviously, the 'dashpot 80 could be omitted if it were desired to hold the element 69 manually out of contact with the contacts 81, 68 long enough to permit the motor to come up to speed before establishment of the circuit by the switch parts 61, 68 and 89.. Of course, if the switch isopenpas will be the case if the receiver pressure is greater than the predetermined minimum for which the switch. mechanism 82 is set, the compressor will not load, even on the upward movement to the position shown in Fig. l of the contact element 69.

It will be appreciated that I have provided an exceedingly simple and very effective arrangement for maintaining a compressor unloaded during the time when the latter is comingup to speed. Moreover, with a minimum ofmechanism, this function is accomplished, and the compressor system enabled to operate under the load-and-unload system of output control.

While I have in this application specifically described one embodiment which the invention may assume in practice, it will be understood that this embodiment of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without. departing ,irom its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is z I 1. In combination, a pump having unloading means, pressure responsive controlling means for said unloading means, a driving motor for said pump, motor controlling means includinga member movable from one predetermined position to ,another to start said motor and out of the lat- ,a predetermined position to make said unloading means inoperative, a driving motor for said pump, and means for starting said motor connected with said member and moving'the latter onto! said predetermined position when actuated to start said motor, and means for maintaining said motor in operation when said member is returned to said predetermined position.

3. In combination, a pump having unloading means, an electric control for the latter including a pressure responsive switch, a solenoid, and a further switch, both said pressure responsive switch and said further switch having to be closed to effect loading, a pump driving motor having a starting'switch, and controlling means 'for the latter necessitating opening of said second mentioned switch during starting of the pump driving motor,

4. In combination, apump having unloading means, an electric control for the latter including a pressure responsive switch, a solenoid, and a further switch, both said pressure responsive switch and said further switch having to be closed to effect loading, apump driving motor having an electrically actuated starting switch, an operating magnet for the latter having a control circuit established by said further switch when thelatter is moved to open the circuit of said unloadng means control,'and means for maintaining said magnet energized independentiy of said further switch, whereby reclosing of said further switch after motor starting is possible. v

5. In combination, a pump having unloading means, an electric control for the latter including a pressure responsive switch, a solenoid, and

a further swi ch, both said pressure responsive switch and said further switch having to be closed to eflect loading, means for automatically mov- 'means operable to open said parallel circuit and deenergize said operating magnet.

6. In combination, a pump having unloading means, a driving motor for said pump, a starting switch for said motor having an operating magnet, controlling means for said unloading means including an operating solenoid energized to effect loading, separate circuits for.said magnet and solenoid, a switch element operative in different positions thereof to establish said separate circuits, and means operable by said magnet for maintaining a holding circuit through said magnet.

"'7. In combination, a pump having unloading means, a driving motor for said pump, .a starting switch for said motor having an operating magnet, controlling means for said unloading means including an operating solenoid energized to effect loading, separate circuits for said magnet and solenoid respectively, a switch element operative in different positions thereof to form an element of said separate circuits, means for automatically restoring said switch element, when moved'therefrom, to a position to form an ele-, ment, of the solenoid controlling circuit, means operative on closure of said starting switch due I to movement of said switch element into said magnet circuit to create a holding circuit around said switch element for said magnet, and means operable to open said holding circuit and deenergize said magnet.

8. In combination, a pump having unloading means, a driving motor for said pump, a starting -switch for said motor having an operating magnet, controlling means for said unloading means including an operating solenoid energized to effect loading, separate circuits forsald magnet and solenoid respectively, the circuit for said solenoid containing a pump-discharge-pressure responsive switch, a switch element operative in diflerent positions thereof to form an element of said separate circuits, means for automatically restoring said switch element, when moved therefrom, to a position to form an element of the solenoid controlling circuit, means operative on closure of said starting switch due to movement of said switch element into said magnet circuit to create a holding circuit around said switch element for said magnet, and means operable to open said holding circuit and deenergize said magnet. v

9. In combination, a pump having unloading means, a driving motor for saidpump, a starting switch for said motor having an operating magnet, controlling means for said unloading means including an operating solenoid energized to effect loading, separate circuits for said magnet and solenoid respectively, a switch element operative in diflerent positions "thereof to form an element of said separate circuits, means for automatically restoring, after a predetermined time lapse, said switch element, when moved therefrom, to a position to form an element of the solenoid controlling circuit, and means operative on closure or said starting switch due to movement of said switch element into said magnet circuit to create a holding circuit'around said switch element for said magnet.

10. In combination, a pump having unloading means, a driving motor for said pump, a starting switch for said motor having an operating magnet, controlling means i'or said unloading means including an operating solenoid energized to effect loading, separate circuits for "said magnet and solenoid respectively, the latter circuit containing a pump discharge pressure responsive switch, a switch element operative in difierent positions thereof to establish said separate circuits, means for normally maintaining said switch element in the solenoid circuit and for automatically'returning it thereto after movement to establish the magnet circuit, and means operative on energization of said magnet due to movement of said switch element into said magnet circuit to shunt said switch element in the magnet circuit and maintain said magnet circuit closed after said switch element has been returned to said solenoid circuit.

11. In combination, a pump havingunloading means, a driving motor for said pump, a starting switch for said motor having an operating ,mag-

net, controlling means for said unloading means including an operating solenoid energized to efiectloading, separate circuits (or. said magnet and solenoid respectively, the latter circuit con taining a pump discharge pressure responsive switch, a switch element operative in different positions thereof to establish said separate cirment to establish the magnet circuit, means operative on energization of said magnet due to movement of said switch element into said magnet circuit to shunt said switch element in the magnet circuit, and dashpot means retarding movement of said switch element out of the magnet circuit.

12. In combination, a pump having unloading means, a driving motor for said pump, motor starting and stopping means including a member movable to a predetermined position to eflect motor starting and thereafter movable out of said position without stopping said motor, pressure responsive controlling means for said unloading means requiring the positioning of said member out of said predetermined position thereof to enable loading, and controlling means for the positioning of said member.

13. In combination, a pump having unloading means, pressure responsive controlling means for said unloading means including an operating system in which the operating medium is controlled both in response to pump discharge pressure and through the position of a control element, a driving motor for said pump, and controlling means for said driving motor requiring the positioning of said control element in'a position to precludepump loading to effect motor starting, but not subsequent thereto for continued motor operation, and means for controlling the position of said controlling element.

14. In combination, a pump having unloadin means, pressure responsive controlling means for said unloading means including an operating system in which the operating medium is controlled both in response to pump discharge pressure and through the position of a control element, a driving motor for said pump, and controlling means for said driving motor requiring the positioning of said control element ina position to preclude pump loading to effect motor starting, but not subsequent thereto forcontinued motor operation, and means for controlling the position of said controlling element automatically, normally maintaining the same ina position enabling the effecting of loading.

15. In combination, a pump having unloading means, a controlling system for the latter including a pressure responsive element movable to control the flow of an operating medium and a second element also movable to control the flow of such operating medium, a pump driving motor, and'controlling means for said motor including devices for effecting motor starting rendered operative on movement of said second element to interrupt operating medium flow in said system,-

means for maintaining said motor in operation after starting thereof, independently of the position of said second element, and a further elementmovable to effect motor stopping.

JESS M. BARTHOLOMEW.

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