US2741987A - Safety means for electrically operated pumps - Google Patents

Description

April 11, 1956 F. w. MURPHY ET AL 2,741,987

SAFETY MEANS FOR ELECTRICALLY OPERATED PUMPS Filed Feb. 10. 1953 l I I n I I l 4-5O 55 z4- 5/ 4a 5 INVENTORS Fran/r: WMu rfhz firfar CYMur vhy ATTORNEY5 United States Patent SAFETY MEANS FOR ELECTRICALLY OPERATED PUMPS Frank W. Murphy and Arthur C. Murphy, Tulsa, (this. Application February 10, 1953, Serial No. 336,068 1 Claim. (Cl. 103-25) This invention relates to a safety means for an electrically operated pump.

In an electrically operated pump, particularly of that type having a relatively high voltage motor, when there is a break in the fluid line thereby reducing pressure below the operating minimum, or when for some reason the fluid pressure rises above the desired maximum, the motor and pump will continue to operate and thereby cause a loss of the fluid or cause a break in the pipe line or other equipment due to the excessive high pressure. It is, therefore, an object of this invention to provide an automatically operable safety means connected in circuit with the electromagnetic switch for breaking the circuit to the switch when the fluid pressure reaches a predetermined maximum, and also for breaking the circuit to the switch when the fluid pressure reaches a predetermined minimum.

Another object of this invention is to provide in an automatic safety means of this kind, manually operable means for starting the operation of the motor, and manually operable means for stopping the motor irrespective of the fluid pressure.

A further object of this invention is to provide in combination with a pressure gauge, a pair of normally closed switches mounted on the face of the gauge and operable by the pressure indicating hand for breaking the circuit in which the switches are interposed and in which the switches are connected together in series when the pressure is either at a predetermined minimum or maximum.

A further object of this invention is to provide a safety means which can be mounted as an attachment on a conventional pressure gauge and connected in circuit with an electric motor which may or may not be operated by an electro-magnetic controller.

With the above and other objects in view, our invention consists in the arrangement, combination and details of construction disclosed in the drawing and specification, and then more particularly pointed out in the appended claim.

In the drawing- Figure l is a detailed front elevation of a fluid pressure gauge having a safety means associated therewith and mounted within the housing thereof,

Figure 2 is a fragmentary front elevation of the safety switch means on an enlarged scale,

Figure 3 is a diagrammatic view showing the electric circuits with which the safety means is coupled,

Figure 4 is a fragmentary sectional view taken on the line 4-4 of Figure 2,

Figure 5 is a fragmentary sectional view taken on the line 5-5 of Figure 1.

Referring to the drawing, the numeral designates generally a gauge housing which includes a nipple 11 adapted to be connected to a source of fluid pressure supply. A swingingpointer 12 is formed as a part of the gauge structure and is movable across a graduateddial 13.

In order to provide a means whereby theelectric motor 14 which operates a pump with which thegauge 10 is connected may be cut off when a predetermined maximum 2,741,987 Patented Apr. 17, 1956 pressure is produced, I have provided .a pair of switch membersgenerally indicated at 15 and 16.

Themotor 14 has connected therewith an electromagnetic or solenoid operated switch 17v of conventional construction which includes acoil 18 with acore 19 movable relative to thecoil 18. A pair ofsupplyconductors 20 and 21 forming the supply circuit for themotor 14 are connected toapair of contacts 22 and 23 andzatpair of conductors 24- and 25are connected toa pair ofcontacts 26 and 27. t

Abridging contact member 28 is fixed relative to thecore 19 and is adapted to bridge the twocontacts Hand 26. A second bridging member orcontact 29 is also fixed to the core 19-and is adapted tobridge thecontacts 23 and 27. One end of solenoid coil 18Iis connected as by aconductor 30 to supplyconductor 21.

Aconductor 31 is connected at one end'to the opposite end ofcoil 18 and is connected atthe opposite end thereof toconductor 20. A manuallyoperable switch 32 which is normally biased to open position is interposed inconductor 31 and constitutes astarter switch whereby thecoil 18 may be initially energized to close the power circuit embodied inconductors 21, 24, and 25m themotor 14.

The twosafety switches 15 and'16 areof like construction and each includes an elongated base member 33 which is formed with a right angularly disposedear 34 frictionally engaging a connectingbar 35. The ear 34fhas fixedly secured relative thereto abolt 36 which extends-through the transparent panel 37.- of thegauge 10.

Aknob 38 is threaded onto thebolt 36 on the outer face of thepanel 37 and provides a means whereby the base 33 may be swung with thebolt 36 as an axis.

A fixed contact 39 extends through insulation 40 carried by the base member 33 and is; disposed in confronting position to amovable contact 41 carried by an elongatedresilient bar 42 which is fixedasv at 43* to the outer end of the base bar 33. The base 33:also has extendingright angularly therefrom afiange 44 and an elongated lever 45 ispivotally mounted on. a pivot member46 extending through theflange 44. i i

The lever 45 has extending from the outer end thereof a right angular extension 47 disposed in the path of the swinging of thepointer 12, and an insulated sleeve 48 is mounted on the extension 47. The lever 45 also includes a short lever 49 extending from the opposite side of pivot member 46 and a rightangular projection 50 extends from the short lever 49 and is engageable with thespring contact carrier 42 so that whenpointer 12 bears against extension 47 and rocks this extension with lever 45 toward the base 33,projection 50 will raisespring contact carrier 42 upwardly to circuit breaking position.

Contact 39 is connected by means of aconductor 51 to a manually operated stop switch 52 which is biased to a circuit closing position. Switch 52 is connected by a conductor 53 toconductor 31. The connecting bar ormember 35 is connected between the twoears 34 of theswitch members 15 and 16, and as shown diagrammatically in Figure 3,switch 15 is connected by means of aconductor 54 to a fixedcontact 55. A second fixedcontact 56 is connected by a conductor 57 toconductor 31 and abridging member 58 carried by thesolenoid core 19 is adapted when thecoil 18 is energized to engage thecontacts 55 and 56.

Theswitch members 15 and 16 being normally biased to a circuit closing position will maintain thesolenoid coil 18 energized so long as thepointer 12 is disposed between the predetermined minimum and maximum pressure.

Ashunt switch 59 is connected betweenconductors 51 and 54, being manually operable, and forming a safety switch adapted to be operated before pressure has built up in thegauge 10.

In the use and operation of this safety means, the twoswitch members 15 and 16 are manually adjusted relative to thedial 13 by turning theknobs 38 so as to bodily swing theswitch members 15 and 16 to the predetermined minimum and maximum circuit breaking position. As shown in Figure 1,switch member 15 is adapted to break the electric circuit to thesolenoid 17 whenpointer 12 reaches a minimum of approximately 100 lbs. Switch member 16 is adjusted to break the electric circuit to thesolenoid 17 when a maximum pressure of approximately 500 lbs. has been reached.

These minimum and maximum pressures may be regulated as may be desired so that thesolenoid 17 will be de-energized at any predetermined minimum and maximum. Assuming that themotor 14 is to be initially started,switch 32 is initially closed manually, thereby energizingsolenoid 17 so thatbridging members 23 and 29 will be disposed in bridging position with respect to associatedcontacts 22 and 26,: and 23 and 27. At the sametime bridging member 58 will be disposed in contact withcontacts 55 and 56. At the start of the motor 14 Ipointer 12 will engage extension 47 ofswitch 15 so that the latter switch will be disposed in circuit breaking position. At thistime switch 59 may be initially closed manually and withswitch 32 closed,motor 14 will operate to build up pressure ingauge 10.

Afterpointer 12 has moved clockwise, as viewed in Figure 1, away from extension 47 ofresilient carrier 42 ofswitch 15,contact 41 ofswitch 15 will engage contact 39 of this switch. At the same time switch 16 will be disposed in a circuit closing position so that a circuit will be completed throughswitches 15 and 16,conductors 51, switch 52, andconductor 31 to supplyconductor 20 andconductor 54 throughbridging member 58 and conductor 57 toconductor 30.

Thesolenoid 17 will thereby be maintained energized until a maximum pressure has been built up and when this maximum pressure is reached,pointer 12 will strike extension 47 of switch 16 so as to move the latter switch into a circuit breaking position. With switch 16 in a circuit breaking position, the circuit to one end ofcoil 13 will be broken andsolenoid 17 will thereby be de-energized and bridgingmembers 28 and 29 will be spring urged to a circuit breaking position.

The safety means hereinbefore described is adapted to be connected to the conventionalsolenoid switch which latter switch is connected with a pump operating motor so that the motor will be cut off when a predetermined maximum'pressure has been reached and the circuit will also be broken in the event pressure generated by the pump drops below a predetermined minimum.

We do not mean to confineourselves to the exact details of construction herein disclosed, but claim all variations falling within the purview of the appended claim.

What we claim is:

In combination with an electrically operated pump having an electro-magnetic switch interposed in the power circuit for the motor and a pressure gauge having a rotatablepointer connected with the pump, a pair of normally closed separable contact switches carried by said gauge connected in series with said electro-magnetic switch, means rotatably mounting said pair of switches in said gauge on the axis of rotation of said pointer for angular adjustment relative to each other, and means carried by each of said pair of switches projecting into the path of movement of said pointer whereby said pointer upon contact with said means of one of said pair of switches moves said switch to circuit breaking position when a predetermined maximum pressure is indicated by said pointer and upon contact with the means of the other one of said pair of switches moves said other switch to circuit breaking position when a predetermined minimum pressure is indicated by said pointer.

References Cited in the file of this patent UNITED STATES PATENTS 821,747 Richards May 29, 1906 1,253,687 Hicks Jan. 15, 1918 1,570,784 Schmidt Ian. 26, 1926 1,589,545 Newkirk June 22, 1926 1,826,089 Persons Oct. 6, 193]. 2,211,052 Cole Aug. 13, 1940

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