CONTROL FOR SUMP PUMP

• US 3,667,022 A
• Filed: 09/02/1970
• Issued: 05/30/1972
• Est. Priority Date: 09/02/1970
• Status: Expired due to Term

• Current Assignee: James L. Quinn
• Original Assignee: James L. Quinn
• Inventors: Quinn, James L.
• Primary Examiner(s): Gilheany, Barnard A.
• Assistant Examiner(s): Langer, Thomas
• Application Number:
  US05/068,940
• Time in Patent Office: 636 Days
• Field of Search: 318/482,642 417/36,44,45 137/392
• US Class Current: 318/482
• CPC Class Codes: G05D 9/12 characterised by the use of electric means

Abstract

A control for a motor driving a sump pump having lower and upper limit probes which includes first and second silicon controlled rectifiers having electrodes which are coupled to the respective probes. The anode-cathode circuit of the second silicon controlled rectifier includes a lamp having an associated photocell. The photocell is connected to the control electrode of a bilateral solid state switch, or triac, which is in series with the motor. The first silicon controlled rectifier is supplied with half-waves of a-c. so that it conducts when the lower limit probe is submerged, but is non-latching. Responsive to such conduction is a capacitor which applies direct voltage to the second silicon controlled rectifier so that the latter latches on when the upper probe becomes submerged. Thus when the water in the sump is pumped down, out of contact with the upper limit probe, the motor continues to be energized. However, when the water is pumped below the level of the lower limit probe, the first silicon controlled rectifier becomes non-conducting and the capacitor no longer applies direct voltage to the second silicon controlled rectifier so that the latter becomes unlatched, thereby turning off the motor. The silicon controlled rectifiers are supplied with current from an isolated secondary winding and the circuit is further isolated from the motor by lamp and photocell.

Claims

1. In a control for a motor driving a sump pump having associated lower and upper limit probes and intended for operation from the regular a-c. supply line, the combination comprising a transformer having its primary winding connected to the a-c. line and having a low voltage secondary winding with an associated rectifier to serve as a source of rectified half-waves of alternating current, first and second silicon controlled rectifiers having anode-cathode circuits connected in series with one another across said source and having control electrodes coupled to the respective lower and upper limit probes, the side of the transformer secondary winding which is associated with the anode terminals being grounded so that the controlled rectifiers are successively conditioned for conduction as the water rises to the level of the lower and upper limit probes, means including a capacitor connected in the anode-cathode circuit of the first controlled rectifier for applying direct voltage to the anodecathode circuit of the second controlled rectifier for latching the same in the conductive state until such time as the water level drops below the level of the lower limit probe, a lamp connected in series with the anode-cathode circuit of the second controlled rectifier, a photocell close-coupled to the lamp so as to be responsive to the illumination thereof, a bilateral solid state switch having a load circuit connected in series with the motor and supply line and having a control electrode coupled to the photocell so that the motor remains turned on as long as current flows in the anode-cathode circuit of the second controlled rectifier.

2. In a control for a motor driving a sump pump having lower and upper limit probes, the combination comprising a transformer source of half-waves of a-c., a reference ground connection at the output side of the transformer, solid state switch having an anode-cathode circuit and a control electrode, a second solid state switch having an anode-cathode circuit and a control electrode, the anode-cathode circuits being connected in series with one another to the source of pulses, a capacitor connected in series with the anode-cathode circuit of the first switch and in parallel with the anode-cathode circuit of the second switch, the control electrode of the first switch being connected to the lower limit probe so that when the lower limit probe is submerged half-waves of current flow through the first switch to charge the capacitor, the second switch having a latching characteristic when energized by direct voltage and the control electrode of the second switch being connected to the upper limit probe so that when the upper limit probe is submerged by rising of the water level in the sump latched current flows through the second switch, and isolating relay means responsive to current flow through the second switch for turning on the motor with the latter being monitored on by reason of the latching until the water level drops below the lower limit probe.

3. In a control for a motor driving a sump pump having lower and upper limit probes, the combination comprising a transformer source of rectified half-waves of a-c., a reference ground connection at the output side of the transformer, first and second solid state switches having anode-cathode circuits connected to the source and the ground and having lower and upper control electrodes respectively connected to the probes, a capacitor connected in the anode-cathode circuit of the first switch so that the capacitor is charged whenever the first probe is submerged, means for applying direct voltage from the capacitor to the anode-cathode circuit of the second switch, the second switch having a latching characteristic when energized by direct voltage so that when the second probe is submerged by reason of a rise in the water level, latched current flows through the second switch, and relay means responsive to the current flow through the second switch but electrically isolated therefrom for energizing the motor until the capacitor is discharged by reasons of dropping of the water level below the lower limit probe.

4. In a control for a motor driving a sump pump having lower and upper limit probes, the combination comprising a transformer source of half-waves of a-c., a reference ground connection at the output side of the transformer, first and second silicon controlled rectifiers having their anode-cathode circuits connected to the source and having control electrodes respectively connected to the lower and upper probes, means including a capacitive element for operatively coupling the anode-cathode circuit of said first silicon controlled rectifier to the anode-cathode circuit of said second silicon controlled rectifier so that a rise in water level to the lower probe causes conduction in the first controlled rectifier for charging of the capacitor for application of direct voltage to the second controlled rectifier and a rise in water level to the upper probe causes flow of current in the second controlled rectifier which is latchingly maintained until the water level drops below the level of the lower probe, and solid state relay means responsive to flow of current in the second controlled rectifier but electrically isolated therefrom for energizing the motor.

5. In a control for a motor driving a sump pump having lower and uPper limit probes, the combination comprising a transformer source of half-waves of a-c., a reference ground connection at the output side of the transformer, a solid state switch having an anode-cathode circuit connected to the source and having a control electrode connected to the upper probe, said switch having a latching characteristic when its anode-cathode circuit is energized by an uninterrupted forward biasing direct voltage, means including a capacitor coupled in series with the lower probe for applying an uninterrupted, forward biasing direct voltage component to the anode-cathode circuit of said switch as long as the lower probe is submerged so that when the control electrode is energized due to a rise in water level to the upper probe the switch is latched on and continues conduction until the water level drops below the lower probe despite the subsequent de-energization of the control electrode associated with said solid state switch, and solid state relay means responsive to the flow of current in the anode-cathode circuit but electrically isolated therefrom for energizing the motor.

6. In a control for a motor driving a sump pump having lower and upper limit probes, the combination comprising a transformer source of half-waves of a-c., a reference ground connection at the output side of the transformer, a solid state switch having an anode-cathode circuit connected to the source and having a control electrode connected to the upper limit probe, said switch having a latching characteristic when its anode-cathode circuit is energized by an uninterrupted, forward biasing direct voltage, a lamp connected in series with the anode-cathode circuit, a photocell coupled to the lamp, a bilateral solid state switch having a load circuit connected in series with the motor and having a control electrode coupled to the photocell for turning on the motor, and means including a capacitor coupled in series with the lower limit probe for applying an uninterrupted, forward biasing direct voltage to the anode-cathode circuit of said solid state switch to latch in the solid state switch for continued running of the motor, despite the subsequent de-energization of the control electrode associated with said solid state switch, until the water drops below the lower limit probe.

7. In a control for a motor driving a sump pump having associated lower and upper limit probes and arranged for powering from the regular a-c., power line, the combination comprising a transformer having its primary connected to the power line and having a low voltage secondary winding and an associated full-wave rectifier for providing a continuous train of rectified half-waves of a-c., a solid state switch having an anode-cathode circuit connected to the source of rectified half-waves and having a control electrode connected to the high limit probe, the switch having a latching characteristic when its anode-cathode circuit is energized by an uninterrupted, forward biasing direct voltage, a lamp connected in series with the anode-cathode circuit, a photocell closely coupled to the lamp but electrically isolated therefrom, a bilateral solid state switch having a load circuit connected in series with the motor and having a control electrode connected to the photocell so that when the water rises to the level of the upper limit probe conduction occurs in the solid state switch, means in series with and controlled by the lower limit probe for applying an uninterrupted, forward biasing direct voltage to the anode-cathode circuit of the solid state switch as long as the lower limit probe is submerged thereby to produce latching of the solid state switch and continued running of the motor, despite the subsequent de-energization of the control electrode associated with said solid state switch, until the water drops below the lower limit probe whereupon the motor is turned off, the lower limit probe being effectively connected to one terminal of the secondary winding and another terminal of the secondary winding being grounded so that alternating voltage is continuously applied to the lower limit probe thereby to minimize electrolytic plating or corrosion of the lower limit probe during sustained contact with the water in the sump.