US2997609A

US2997609A - Starting switch for submersible pumps

Info

Publication number: US2997609A
Application number: US674076A
Authority: US
Inventors: Kenneth R Lung
Original assignee: Tait Manufacturing Co
Current assignee: Tait Manufacturing Co
Priority date: 1957-07-25
Filing date: 1957-07-25
Publication date: 1961-08-22
Anticipated expiration: 1978-08-22

Description

2, 1961 K. R. LUNG 2,997,609

STARTING SWITCH FOR SUBMERSIBLE PUMPS Filed July 25, 1957 2 Sheets-Sheet l 23 FIG-1 FIG-2 Z5| 2! 5'4 INVENTOR.

KENNETH R. LUNG BY WWW, 6

ATTORNEYS United, States Pate 2,997,609 STARTING SWITCH FOR SUBMERSIBLE PUMPS Kenneth R. Lung, Dayton, Ohio, assignor to The Tait Manufacturing Company, Dayton, Ohio, a corporation of Ohio Filed July 25, 1957, Ser. No. 674,076 Claims. (Cl. 310--87) This invention relates to submersible pump assemblies of the type including a motor as a part of the entire assembly which is submerged in a well.

The invention has special relation to electric motors for use in such submersible pump assemblies and which are intended to be filled with liquid during operation thereof, and the invention is directly concerned with controls for such submersible motors. Thus it is a primary object of the invention to provide a novel, simple and eifective construction for the starting switch of a liquid-filled motor which shifts the motor circuits between the starting and running conditions thereof.

Another object of the invention is to provide a submersible motor as outlined above wherein the starting switch is caused to shift from its starting position to its running position as the result of a pressure condition which is developed within the liquid-filled motor casing by a pumping member driven by the motor.

An additional object of the invention is to provide a starting switch construction for a submersible motor as outlined above wherein the motor shaft carries a special impeller which develops hydraulic pressure in the liquidfilled motor casing as the motor comes up to speed and wherein this developed hydraulic pressure causes movement of an operating member for the switch in the direction to shift the motor circuits from starting to running condition.

A further object of the invention is to provide a starting switch construction for a submersible motor as outlined above wherein the impeller which causes operation of the starting switch also constitutes a thrust bearing for the motor shaft.

A still further object of the invention is to provide a liquid-filled submersible motor wherein the starting switch is operated by a member supported for guided movement in a tubular guideway which is in turn connected in such manner with a pumping member driven by the motor that when the motor comes up to speed, this pumping member develops hydraulic pressure in this guideway effective to move the operating member for the switch in the direction to shift the switch from starting to running position.

It is also an object of the invention to provide a submersible motor having one or more of the characteristics outlined above which incorporates a flexible diaphragm member forming a pressure connection between the interior of the motor casing and the surrounding atmosphere to maintain the casing sealed and filled with liquid when the casing is submerged in a surrounding liquid in order to assure proper response by the control mechanism for the starting switch to the pressure condition developed within the casing by operation of the motor.

Additional objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims- In the drawings-- FIG. 1 is an elevational view illustrating a submersible pump assembly incorporating a liquid-filled electric motor constructed in accordance with the invention;

FIG. 2 is an enlarged fragmentary view in axial section through the lower end of the motor portion of the assembly of FIG. 1;

FIG. 3 is a detail section on the line 3-3 of FIG. 2;.

FIG. 4 is a wiring diagram for the motor of FIG. 2;

FIG. 5- is a view similar to FIG. 2 showing another control switch construction in accordance with the invention;

FIG. 6 is an enlarged fragment of FIG. 5 taken approximately on the line 6-6 of FIG. 5 and showing the parts at rest;

MG. 7 is a further enlarged fragment of FIG. 6 showing the parts in the positions they occupy when the motor is at operating speed;

FIG. 8 is a section on the line 8-8 of FIG. 6; and

FIG. 9 is a wiring diagram for the motor of FIGS. 58.

Referring to the drawings, which illustrate preferred embodiments of the invention, the submersible motor assembly shown in FIG. 1 includes a motor casing 16 and a pump shell 11 connected by an intake cap 12 covered by a screen 13. The motor is shown in FIG. 2 as of the oil-filled type, and the lower end of the motor casing is connected with a housing which forms an extension thereof and is in turn provided at its lower end with a flexible seal between its interior and the outside atmosphere, comprising a diaphragm 16 of rubber material housed in an end cap17 having an opening 18 therethrough for direct access by the outside atmosphere to one side of the diaphragm 16. Details of the structure of these parts of the pump assembly are disclosed in my copending applications Serial No. 633,412, field January 29, 1957, and Serial Nos. 646,667 and 646,693, filed March 18, 1957, all of which are assigned to the same assignee as this application.

The motor shown fragmentarily in FIG. 2 may be of the construction shown in detail in my copending application Ser. No. 672,654, filed July 18, 1957, and also assigned to the same asignee as this application. The motor includes a stator 20 which carries the main field winding 21 and the starting winding '22. The rotor 23 is secured on the motor shaft 25 which is mounted at its upper end in the end bracket 26 as shown in one or more of the above applications. The lower end of shaft 25 is supported by a bushing 27 in a bracket 30 secured between the end ring 31 on casing 10 and the end housing 15 by bolts 32 as shown in FIG. 2.

The motor in casing 10 is shown as of the split phase type requiring a single pair of leads L and L which are indicated in FIG. 1 as included in cable 33. The starting and running circuits for the motor are shown fragmentarily in FIG. 4 as including a starting switch 35 and a starting capacitor 36 connected with the starting winding 22 across the lines L and L in parallel with the main winding 21. This is a well known and conventional starting circuit, and the switch 35 is intended to be opened when the motor comes up to speed in order to establish the running circuit for the motor utilizing only the main winding 21. The present invention is particularly directed to the mechanism for operating this switch 35.

Referring particularly to FIG. 2, the switch 35 is shown as of the mercury type, and it includes an arm 40 pivoted at 41 on a mounting 42 carried by the bracket 30. A mercury switch is particularly advantageous for use in an oil filled motor as shown, since its contacts are sealed from access by the oil and therefore not only are protected thereby against excessive burning but also are prevented from causing cracking of the oil due to arcing when the switch changes positions. A spring 44 on a guide pin 45 is arranged to bias the switch arm 40 in clockwise direction as viewed 11 FIG. 2 and thereby to shift switch 35 to its open position. FIG. 2 also shows how the capacitor 36 is readily mounted within the housing 15, as by means of suitable centering rib portions 37 of the housing.

Provision is made by the invention for biasing the switch 35 to its closed position when the motor is at rest and for developing a hydraulic pressure condition within the motor casing as the motor comes up to speed which will cause shifting of switch 35 to its open position in order to change the motor circuit from starting to running condition. The lower end of shaft includes a hollow portion 50 extending upwardly from the lower end thereof. A plunger 51 is mounted for sliding telescoping movement in the guideway provided by this hollow shaft portion 50 and a spring 52 is arranged in the shaft portion St? to bias the plunger 51 downwardly against the switch arm 40. The spring 52 is of greater force than the spring 44 so that when the motor is at rest, the switch is biased to its closed position shown in FIG. 4.

The outer diameter of the hollow shaft portion is of reduced diameter to provide a circumferential shoulder 54, and an annular disk is secured thereon as by press fitting. The proportions of these parts are such that the lower surface of the disk 55 is in thrust bearing relation with the upper end surface of the bracket 30. In addition, the disk 55 is provided with a plurality of passages 56, four being shown, which extend radially outwardly from an internal peripheral groove 57, and the shaft 25 is provided with radial ports 58 which connect the groove 57 with the hollow inner portion 50 of the shaft. These ports and passages thus cause the disk 55 to function as a centrifugal impeller upon rotation of the shaft, and the hollow shaft portion 50 cooperates with the ports 58 to form the inlet of the impeller.

With this construction, when the motor is at rest, the parts will occupy the relative positions shown in FIGS. 2 and 4, with the spring '52 biasing the plunger 51 in the direction to hold switch 35 in its starting position, i.e. closed, and with the entire open space within the hollow shaft portion 50 being filled with oil (not shown). When the motor is first energized, by operation of the usual remotely located main switch (not shown), the impeller will begin to revolve with the motor shaft. As it revolves, the impeller 55 will develop suction within the shaft portion 50 by tending to discharge through its outlets 56 the oil which was occupying the space 50. This suction will be effective on the plunger 51 in the upward direction against spring '52, and when this developed suetion is suflicient to overcome the force of spring 52, which occurs when the motor has come up to speed, the plunger will move upwardly and cause switch arm 40 similarly to rise in response to its spring 44 and thereby to shift switch 35 to its running position wherein it disconnects the capacitor 35 and starting winding 22 from the motor circuit to establish the running circuit as already described.

This invention accordingly provides a compact and effective mechanism for controlling the starting switch of a liquid-filled motor by utilizing the presence of the liquid in the motor casing. In addition to the fact that operation of this mechanism is simple and sure, construction of its component parts is also simple and does not require close tolerances. In particular, it is not essential that the plunger 51 fit closely within its guideway formed by the hollow shaft portion 50, and in fact it is satisfactory if there is some limited clearance around the plunger for leakage of the oil, provided only that this leakage should not reach a point such that it will supply the suction demand of the impeller 55 to an extent permitting the spring 52 to overcome the desired suction force on the plunger.

It will be apparent that the principles of this invention are applicable to a variety of motors, including waterfilled motors as well as those of the type filled with oil or other insulating liquid, provided only that the motor casing be normally filled with a liquid capable of being pumped by the impeller on the motor shaft. It is also apparent that the switch construction of the invention is not limited to a particular motor circuit but can be employed in combination with a wide variety of circuit arrangements requiring operation of a switch which is responsive to motor speed to shift between the starting circuit for the motor and its running circuit, and such shifting may require either opening or closing of the switch depending upon the particular circuit. The wide applicability of the invention is illustrated in part by another form thereof which is shown in FIGS. 5-9 in connection with a motor of the capacitor-run type.

In FIG. 5, the motor is housed in a tubular casing 60 which in use is filled with a suitable liquid. The motor shaft 61 projects at its upper end through a rotary seal indicated diagrammatically at 62 in the bracket 63 corresponding to the bracket 26 in FIG. 1 by which the motor and pump sections of the assembly are connected. The lower end of the shaft 61 is mounted by a bearing 65 in a housing 66 to which the tubular extension 67 of the casing is similarly attached.

The motor stator 70 within the casing 60 is indicated as including a main winding 71 and a starting winding 72, with the latter being connected across leads L and L in series with the running capacitor 73. The starting capacitor 74 and the. starting switch 75 are connected in series with each other and in parallel with the main running capacitor 72 The two

capacitors

73 and 74 are both shown in FIG. 5 as mounted within the casing extension 67 by means of a bracket 77 depending from the housing 66.

The bottom end of the casing extension 67 is provided with a flexible diaphragm 80 of the bellows type which is mounted on an annular plug 81 secured within the open lower end of the casing extension 67 by screws 82 and an O-ring S3. The pont 85 through plug 81 connects the outside atmosphere with the interior of the bellows diaphragm 80, and the dotted line showing in FIG. 1 illustrates how the diaphragm 80 may expand under the pres sure or" the outside liquid entering through the port 85 to maintain the interior of the motor casing uniformly filled with oil in the event of leakage. If, however, such leakage should be excessive, a safety switch 88 is mounted on the lower end of the bracket 77 for operation by diaphragm S5 in its fully expanded position, the switch 88 being a shut-off switch for the motor as indicated in PEG. 9.

The starting switch 75 is mounted within the housing 66 by a bracket 9d located to align the operating button 1 of switch 75 in line with the motor shaft 61. The lower end of the motor shaft carries a centrifugal impeller secured thereon by a screw and a lock washer 7, and the impeiler 95 includes a plurality of radially extending outlet passages 9'3 and an extended tubular inlet portion 99 of cylindrical configuration which forms a guideway for a plunger 10-3 which is the operating member for the switch 75. The compression spring 101 is mounted in inlet 99 between plunger and the end of the motor switch to bias the plunger downwardly and thus to cause its pin portion 102 to engage the switch button 91 and to close switch 75.

The operation of this form of the invention is similar to that already described in connection with FIGS. 1-4. When the motor is at rest, the parts occupy the relative positions shown in FIG. 6, with the spring 101 holding switch button 91 downwardly against the internal spring of the switch 75 indicated diagrammatically at 103 in FIG. 9. When the motor comes up to speed, the suction developed in the inlet 99 will cause plunger 100 to raise against spring 101 and thus cause switch 75 to be opened by its spring 103. It will therefore be apparent that this same switch operating mechanism could be employed in the motor of FIGS. 24, and vice versa, and that the same advantages will be available with either arrangement.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be U made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, 2. motor including a motor shaft within said casing, means for maintaining said casing substantially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, an operating member for said switch mounted in said casing and surrounded by the liquid Within said casing, means biasing said operating member in the direction to shift said switch to said starting position, a pumping member in said casing operated by said motor shaft to circulate the liquid within said casing, and means communicating with said pumping member and responsive to the hydraulic force developed by said pumping member in said liquid for creating a pressure differential on opposite sides of said operating member to cause said operating member to move against said biasing means and thereby to shift said switch to said running position.

2. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, a motor including a motor shaft within said casing, means for maintaining said casing substantially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, an operating member for said switch mounted in said casing and surrounded by the liquid, means biasing said operating member in the direction to shift said switch to said starting position, a centrifugal impeller on said motor shaft within said liquid-filled casing, and means actuated by the flow of the liquid in said casing for creating a pressure differential on opposite sides of said operating member in response to operation of said impeller for causing said operating member to move against said biasing means and thereby to shift said switch to said running position.

3. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, a motor including a motor shaft within said casing, means for maintainin said casing substantially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a mercury switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, means mounting said switch within said casing for tilting movement between said positions, an operating member for said switch, means biasing said operating member in the direction to tilt said switch to said starting position, a pumping member in said casing operated by said motor shaft to circulate the liquid within said casing, and means responsive to the suction force developed by said pumping member in said liquid for creating a pressure differential operating on opposite sides of said operating member and against said biasing means for causing said operating member to move against said biasing means and thereby to tilt said switch to said running position.

4. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, a motor including a motor shaft within said casing, means for maintaining said casing substantially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, an operating member for said switch, guide means supporting said operating member in said casing for operating movement with respect to said switch, means biasing said operating member in the direction to shift said switch to said starting position, and means responsive to the operation of said motor shaft for developing hydraulic pressure in said casing and cooperating with said guide means to provide a pressure differential effective on said operating member in the direction to move said operating member against said biasing means and thereby to shift said switch to said running position.

5. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, a motor including a motor shaft within said casing, means for maintaining said casing substantially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, an operating member for said switch, tubular guide means in said casing supporting said operat ing member therein for operating movement with respect to said switch, means biasing said operating member in said guide means in the direction to shift said switch to said starting position, a centrifugal impeller mounted on said motor shaft and having an inlet, and means connecting said inlet with said guide means to cause said impeller to develop suction within said guide means effective on said operating member in the direction to move said operating member against said biasing means and thereby to shift said switch to said running position.

6. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, 2. motor including a motor shaft within said casing, means for maintaining said casing substantially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, a centrifugal impeller mounted on said motor shaft and having an extended tubular inlet, an operating member for said switch supported in said inlet for operating movement with respect to said switch, means biasing said operating member in the direction to shift said switch to said starting position when said shaft is stationary, and said operating member being movable in said inlet against said biasing means in response to the suction developed in said inlet by operation of said motor to shift said switch to said running position.

7. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, a motor including a motor shaft within said casing, means for maintaining said casing substantially filled with liquid during operation of said motor, circuit means defining diiferent starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, said shaft including a hollow portion extending upwardly from the lower end thereof, an operating member for said switch supported in said hollow shaft portion for operating movement with respect to said switch, means biasing said operating member in the direction to shift said switch to said starting position when said shaft is 7 stationary, and a centrifugal impeller mounted on said shaft with the interior thereof connected with said hollow shaft portion to develop suction in said hollow shaft portion effective on said operating member in the direction to move said operating member against said biasing means and thereby to shift said switch to said running position.

8. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with. liquid, a motor including a motor shaft within said casing, means for maintaining said casing substantially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, bracket means in said casing journaling the lower end portion of said shaft, said shaft including a hollow portion extending upwardly from the lower end thereof, an operating member for said switch supported in said hollow shaft portion for operating movement with respect to said switch, means biasing said operating member in the direction to shift said switch to said starting position when said shaft is stationary, a centrifugal impeller mounted on said shaft above said bearing means with the interior thereof connected with said hollow shaft portion to develop suction in said hollow shaft portion effective on said operating member in the direction to move said operating member against said biasing means and thereby to shift said switch to said running position, and the lower surface of said impeller being constructed and positioned to form a thrust bearing with respect to said bracket means.

9. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, a motor including a motor shaft within said casing, means for maintaining said casing substan tially filled with liquid during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, bracket means in said casing journaling the lower end portion of said shaft, said shaft including a hollow portion extending upwardly fnom the lower end thereof through said bracket means, an operating member for said switch supported in said hollow shaft portion for operating movement with respect to said switch, means biasing said operating member in the direction to shift said switch to said starting position when said shaft is stationary, an annular disk secured on said shaft above said bracket means in thrust bearing relation therewith, said disk having a plurality of passages extending outwardly therethrough from the inner periphery thereof, and said shaft having ports therein connecting said hollow shaft portion with said passages to develop suction in said hollow shaft portion upon rotation of said shaft effective on said operating member in the direction to move said operating member against said biasing means and thereby to shift said switch to said running position. i

10. In a submersible motor construction of the character described adapted to be submerged in a surrounding liquid, the combination of a casing constructed to be filled with liquid, a motor including a motor shaft within said casing, means for sealing said casing against the escape of liquid therefrom during operation of said motor, circuit means defining different starting and running circuits for said motor, a switch included in said circuit means and shiftable between a starting position establishing said starting circuit and a running position establishing said running circuit, an operating member for said switch mounted in said casing, means biasing said operating member in the direction to shift said switch to said starting position, a pumping member in said casing operated by said motor shaft to circulate the liquid within said casing, means responsive to the pumping force developed by said pumping member'in said liquid for causing said operating member to move against said biasing means and thereby to shift said switch to said running position, flexible diaphragm means forming a pressure connection between the interior of said casing and the surrounding atmosphere to maintain said sealed casing substantially filled with liquid when said casing is submerged in a surrounding liquid for assured response of said responsive means to said pumping force, and a shutoff switch for said motor mounted in said casing in the path of movement of said diaphragm inwardly of said casing for operation by said diaphragm in response to a predetermined reduction in the volume of said liquid within said casing.

References Qited in the file of this patent UNITED STATES PATENTS 1,946,165 Irwin Feb. 6, 1934 2,055,480 Coberly Sept. 24, 1936 2,219,199 Renner Oct. 22, 1940 2,539,048 Arutunolf Jan. 23, 1951 2,752,516 Kalikow June 26, 1956 FOREIGN PATENTS 897,231 France May 22, 1944