Submersible pump with integrated liquid level sensing and control system

• US 20070048157A1
• Filed: 08/24/2005
• Published: 03/01/2007
• Est. Priority Date: 08/24/2005
• Status: Active Grant

• Current Assignee: SPX FLOW, Inc. (SPX Corporation)
• Original Assignee: Johnson Pumps of America, Inc. (SPX Corporation)
• Inventors: Collins, Michael, Assessor, Gerald
• Granted Patent: US 7,625,187 B2
• Time in Patent Office: Days
• US Class Current: 417/423.300
• CPC Class Codes: F04D 15/0218 the condition being a liquid level or a lack of liquid supply

Abstract

In accordance with one embodiment of the present invention, there is provided a submersible pump that includes a pump housing forming a main compartment for receiving a pump impeller and having liquid entrance and exit openings in said main compartment, and an impeller mounted in the main compartment. The pump housing is adapted for submersion in a body of liquid whose level is to be controlled, and a sealed auxiliary compartment is formed as an integral part of the housing and located to be at least partially submerged in the liquid body. A drive motor is coupled to the impeller for rotating the impeller to eject liquid from the main compartment through the exit opening. An electric-field sensor is mounted in the sealed auxiliary compartment for detecting the elevation of the surface of the liquid body adjacent the sealed auxiliary compartment. At least one controllable switch is connected in the power supply line for controlling the supply of power to the drive motor, and the electric-field sensor is connected to the controllable switch for opening and closing the switch in response to changes in the detected elevation of the surface of the liquid body adjacent the outer surface of the sealed auxiliary compartment.

Claims

1. A submersible pump comprising

a pump body forming a main compartment having liquid intake and discharge openings, said pump housing being adapted for submersion in a body of liquid whose level is to be controlled,

a drive motor in said main compartment,

an impeller coupled to the lower end of said drive motor for ejecting liquid through said discharge opening when said impeller is rotated by said drive motor,

a sealed auxiliary compartment formed as an integral part of said pump body and located to be at least partially submerged in said liquid body,

at least one electric-field sensor mounted in said sealed auxiliary compartment adjacent an outer wall thereof for detecting the elevation of the surface of said liquid body adjacent the outer surface of said sealed auxiliary compartment,

a pair of electrical conductors for coupling said electric-field sensor and said drive motor to a power supply, and

a controllable switch coupled to said conductors for controlling the supply of electrical power to said drive motor, said electric-field sensor being connected to said controllable switch for turning said drive motor on and off in response to changes in the detected elevation of the surface of said liquid body adjacent the outer surface of said sealed auxiliary compartment.

2. The submersible pump of claim 1 which includes a pair of said electric-field sensors located at different elevations, the upper sensor producing a signal for turning said drive motor on after the surface of said liquid body rises to a first predetermined elevation, and the lower sensor producing a signal for turning said drive motor off when the surface of said liquid body drops to a second predetermined elevation.

3. The submersible pump of claim 2 wherein said second predetermined elevation is less than about 0.7 inch above the lowermost surface of said pump.

4. The submersible pump of claim 1 which includes a manual override switch for connecting said drive motor directly to a power supply, bypassing said controllable switch.

5. The submersible pump of claim 1 which includes a detachable volute at the lower end of said main compartment to facilitate access to said impeller.

6. The submersible pump of claim 5 which includes mechanical connectors formed as integral parts of said pump body and said volute for detachably attaching said volute to said pump body, said connectors including cam surfaces for drawing said volute tightly against said pump body as said volute is attached to said pump body.

7. The submersible pump of claim 6 wherein said connectors are flanged tabs extending upwardly from the top edge of said volute, and cooperating lugs on said pump body for engaging said flanged tabs as said volute is rotated relative to said pump body, at least one of the engaging surfaces of said flanged tabs and lugs forming said cam surfaces.

8. The submersible pump of claim 7 wherein said drive motor is contained in a motor housing surrounded by an O-ring that engages an opposed surface of said main compartment to form a liquid-tight seal between upper and lower regions of said main compartment.

9. The submersible pump of claim 7 wherein said upper portion of said main compartment above said O-ring is sealed against the entry of liquid.

10. The submersible pump of claim 1 which includes a strainer detachably attached to the lower end of said pump body to prevent large solid material from entering said main compartment.

11. The submersible pump of claim 10 wherein the lower portion of said strainer is tapered inwardly to reduce the footprint of said strainer so as to facilitate the mounting of said pump in cramped spaces.

12. The submersible pump of claim 1 wherein said electric-field sensors are mounted on a printed circuit board attached to the inside surface of an outer wall of said auxiliary compartment.

13. The submersible pump of claim 12 wherein said electrical conductors pass through a sealed aperture in a wall of said auxiliary compartment and are electrically connected to conductors on said printed circuit board.

14. The submersible pump of claim 12 wherein said controllable switch is mounted on said printed circuit board, and which includes electrical conductors connecting said controllable switch to the upper end of said drive motor.

15. The submersible pump of claim 1 which includes a spout extending outwardly from said discharge opening and adapted to receive a check valve.

16. A method of pumping liquid from a liquid body with a pump submerged in said liquid body whose level is to be controlled, said method comprising

submerging a pump body forming a main compartment having liquid intake and discharge openings in said body of liquid whose level is to be controlled, said main compartment containing a drive motor connected an impeller for ejecting liquid from said body of liquid outwardly through said discharge opening when said impeller is rotated by said drive motor,

detecting the elevation of the surface of said liquid body with at least one electric-field sensor mounted in a sealed auxiliary compartment formed as an integral part of said pump body and located to be at least partially submerged in said liquid body, said sensor being located adjacent an outer wall of said sealed auxiliary compartment and producing an output signal that changes with the presence or absence of liquid along the outer surface of said auxiliary compartment adjacent said sensor, and

controlling the supply of electrical power to said drive motor in response to changes in said output signal from said sensor.

17. The method of claim 16 which includes a pair of said electric-field sensors located at different elevations, the upper sensor producing a signal for turning said drive motor on when the surface of said liquid body rises to a first predetermined elevation, and the lower sensor producing a signal for turning said drive motor off when the surface of said liquid body drops to a second predetermined elevation.

18. The method of claim 17 wherein the turning on of said drive motor is delayed by a predetermined delay interval following the detection of the rising of the surface of said liquid body to said first predetermined elevation