Apparatus for controlling a pumpjack prime mover

In a control system for the control of a prime mover of an oil well pumpjack apparatus which drives a downhole pump by means of a rod string, wherein the pumpjack unit includes structural components affixed to one another for reciprocating the rod string, the improvement comprising:

• control means by which the prime mover is selectively energized and de-energized;
• means measuring relative movement between said structural components, and converting the measurement into a pump-off signal which varies according to the magnitude of the movement;
• means storing said pump-off signal and when a plurality of pump-off signals which exceed a predetermined magnitude are accumulated, said control means is de-energized for a finite period of time and thereafter again energized;
• said pumpjack apparatus includes a gear box driven by the prime mover, and a main frame for supporting the gear box, said means measuring relative movement is connected between the gear box and the main frame of the pumpjack unit.

In a control system for the control of a prime mover of an oil well pumpjack apparatus which drives a downhole pump by means of a rod string, wherein the pumpjack unit includes structural components affixed to one another for reciprocating the rod string, the improvement comprising:

• control means by which the prime mover is selectively energized and de-energized;
• means measuring relative movement between said structural components, and converting the measurement into a pump-off signal which varies according to the magnitude of the movement;
• means storing said pump-off signal and when a plurality of pump-off signals which exceed a predetermined magnitude are accumulated, said control means is de-energized for a finite period of time and thereafter again energized;
• said pumpjack apparatus includes a ground supported main frame;
• said means measuring relative movement is connected to measure movement between the main frame of the pumpjack unit and the ground.

In a control system for the control of a prime mover of an oil well pumpjack apparatus which drives a downhole pump by means of a rod string, wherein the pumpjack unit includes structural components affixed to one another for reciprocating the rod string, the improvement comprising:

• control means by which the prime mover is selectively energized and de-energized;
• means measuring relative movement between said structural components, and converting the measurement into a pump-off signal which varies according to the magnitude of the movement;
• means storing said pump-off signal and when a plurality of pump-off signals are accumulated, said control means is de-energized for a finite period of time and thereafter again energized;
• said pumpjack apparatus is ground supported and said means measuring relative movement is connected between one of the structural components and the ground.

In a control system for the control of a prime mover of an oil well pumpjack apparatus which drives a downhole pump by means of a rod string, wherein the pumpjack unit includes structural components affixed to one another for reciprocating the rod string, the improvement comprising:

• control means by which the prime mover is selectively energized and de-energized;
• means measuring relative movement between said structural components, and converting the measurement into a pump-off signal which varies according to the magnitude of the movement;
• means storing said pump-off signal and when a plurality of pump-off signals are accumulated, said control means is de-energized for a finite period of time and thereafter again energized;
• said pumpjack apparatus includes the following structural components:
• a ground supported main frame, a Samson post, a gear box driven by said prime mover;
• said means measuring relative movement is connected to measure movement between one of said structural components and the ground.

In an oil well pumpjack apparatus having a main frame, a gear box supported on said main frame, and a Samson post affixed to said main frame, said apparatus having a prime mover which is connected to drive said gear box, a rocking beam journaled to said Samson post and connected to be rocked by said gear box, said rocking beam being connected to reciprocate a downhole pump by means of a rod string, and control means by which the prime mover is selectively energized and de-energized;

• an improved control system for said prime mover comprising:
• means for measuring relative movement between said gear box and said Samson post;
• means by which the measured movement is converted into a signal which varies proportional to the magnitude of the measured movement;
• means by which said signal is connected to cause said control means to de-energize said prime mover when the signal amplitude exceeds a predetermined magnitude which is indicative of a pump-off condition.

In a pumpjack apparatus of the type having structural componets spaced from one another and attached together to thereby reciprocate a rod string which extends downhole in a borehole, said structural components including a main frame, a gear box, and a Samson post, a prime mover connected to drive said gear box, means connecting said gear box to rock a rocking beam and thereby reciprocate the rod string, with said prime mover having control means by which it is selectively energized and de-energized, the method of controlling the prime mover according to the steps of:

• measuring the change in distance between two of said structural components as a result of stress and strain induced by the pumping action;
• converting the measured change in distance into a pump-off signal which varies according to the magnitude of the movement;
• storing the pump-off signals which exceed a predetermined magnitude;
• accumulating a plurality of stored pump-off signals and using the stored signals to cause the control means to de-energize said prime mover.