Flow responsive time delay pump motor cut-off logic

An automatically controlled fluid flow responsive method for achieving de-energization of an electric motor of a downhole pump being connected to a production tubing string of a well when flow from the downhole pump becomes abnormally low, wherein a time delay motor cut-off logic is provided having a cut-off timing circuit into which is connected a cut-off delay circuit being adjustable for adjustment thereof within a time delay/voltage range, said method comprising:

• (a) establishing a selective pump cut-off flow rate representing a predetermined minimum rate of discharge flow from the downhole pump;
• (b) receiving a flow signal representing the actual rate of discharge flow from the downhole pump;
• (c) establishing a selected electronically controlled time delay period being initiated when the actual rate of discharge flow from the downhole pump becomes less than said selective pump cut-off flow rate;
• (d) electronically interrupting electrical power supply to said rotary electric motor when said rate of discharge flow remains less than said selective cut-off flow rate for the duration of said electronically controlled time delay period;
• and
• (e) adjusting said cut-off delay circuit to a selected delay value within said time delay/voltage range representing the maximum time period that the pump motor will be permitted to operate in a continuous low flow condition before de-energization of the pump motor by said time delay motor cut-off logic.

A pump discharge flow responsive electronic time delay motor cut-off control system for de-energizing the motor of a downhole pump in the event the discharge flow from the downhole pump becomes abnormally low and remains abnormally low for a predetermined period of time, comprising:

• (a) a flow transducer sensing the discharge flow of the downhole pump and providing a flow transducer voltage representing the discharge flow from the downhole pump;
• (b) an adjustable "set-flow" circuit providing a set-flow voltage range and being adjustable to provide a set-flow voltage output within said set-flow voltage range;
• (c) logic circuitry for comparing said flow transducer voltage and said set-flow voltage and providing a flow related logic output;
• (d) a cut-off delay circuit receiving said flow related logic output and having a maximum delay timing sequence range, said cut-off delay circuit being initiated for timing as long as said flow related logic output represents a rate of pump discharge flow below that set by said adjustable "set-flow" circuit and being terminated when said logic output represents a rate of pump discharge above that set by said adjustable "set-flow" circuit and providing a motor cut-off signal for de-energization of said motor at the completion of said delay timing sequence, said cut-off delay circuit being reinitiated when said flow related logic output is above said set flow voltage;
• and
• (e) an adjustable cut-off delay circuit being provided in said cut-off delay circuit and being selectively positionable for adjustment of the duration of said delay timing sequence.

An electronic flow rate responsive time delay motor cut-off system for a rotary downhole pump in a well for production of well fluid being driven by a rotary electric pump motor having a motor circuit including a motor switch for energizing and de-energizing the motor circuit, comprising:

• (a) a flow transducer being located to sense the rate of discharge flow of said rotary downhole pump and providing electronic flow rate signals indicating the rate of discharge flow from said downhole pump;
• (b) control circuitry having controlling connection with said motor switch for turning said pump switch "on" and "off" for controlling the supply of electrical power to said rotary electric motor;
• (c) an electronic "set flow" circuit being connected to receive said electronic flow rate signals and being adjustable to provide a low flow signal output when said electronic flow rate signals indicate pump discharge flow at or below a set flow rate;
• represented by the setting of said electronic "set-flow" circuit and
• (d) an adjustable cut-off timer circuit being connected to receive said low flow signal output of said electronic "set-flow" circuit and being adjustable to establish a selected time period being initiated by said low flow signal output and being terminated by absence of said low flow signal output, said adjustable cut-off timer circuit being connected to the motor switch of said rotary electric motor and turning said motor switch off for de-energization of said rotary electric motor upon completion of a selected time period during which said low flow signal output being provided showing a continuous low flow condition of rotary downhole pump discharge throughout the entirety of said selected time period.