System and method for monitoring rod position and rotation

Abstract

A system and method for monitoring a rod string used in a pumpjack machine comprises a load-cell device including at least one sensor, a controller configured to receive a signal from the load-cell device and control a pump operation. The load-cell device is attached to a part of the pumpjack machine and wirelessly communicates with the controller to determine the pump operation of the pumpjack machine. The load-cell device is capable of generating a position marker to determine a location of the rod string during a cyclic event of the pumpjack machine. Further, at least one sensor of the load-cell device includes a RF transceiver configured to detect a RF transmission path between the load-cell device and the controller such that the controller is configured to monitor and use the detected RF transmission path to indicate a rotational position and/or a rotational rate of the rod string.

What is claimed is: 
     
         1 . A system for monitoring a rod string used in a pumpjack machine having a gear box and a prime mover, the system comprising:
 a load-cell device including at least one sensor; and   a controller configured to receive a signal from the load-cell device and control a pump operation of the pumpjack machine,   wherein the load-cell device is attached to a part of the pumpjack machine and wirelessly communicates with the controller to determine the pump operation of the pumpjack machine.   
     
     
         2 . The system of  claim 1 , wherein the load-cell device is capable of generating a position marker to determine a location of the rod string during a cyclic event of the pumpjack machine. 
     
     
         3 . The system of  claim 2 , wherein the load-cell device is in communication with a base receiving unit of the controller to transmit the signal having the generated position marker. 
     
     
         4 . The system of  claim 3 , wherein the controller is configured to detect an amount of slippage occurring between a motor output pulley of the prime mover and an input pulley of the gear box and determine a calculated position of the rod string based on the detected slippage. 
     
     
         5 . The system of  claim 4 , wherein the controller is configured to phase the calculated position of the rod string at the location of the rod string determined by the generated position marker. 
     
     
         6 . The system of  claim 1 , wherein the load-cell device is securely attached to the rod string and wirelessly in communication with the controller of the pumpjack machine. 
     
     
         7 . The system of  claim 1 , wherein the at least one sensor of the load-cell device includes an accelerometer, a magnetometer, a Radio-Frequency (RF) transceiver, a proximity sensor, or a strain gauge to generate a position marker of the rod string. 
     
     
         8 . The system of  claim 1 , wherein the pumpjack machine further includes a polished rod connected to a top end of the rod string and a rod rotator installed at the polished rod. 
     
     
         9 . The system of  claim 8 , wherein the load-cell device is securely attached to the polished rod, and placed above the rod rotator and beneath a rod retaining clamp. 
     
     
         10 . The system of  claim 9 , wherein the load-cell device attached to the polished rod rotates together with the rod string such that the load-cell device is configured to index an angular position of the rod string during the pumpjack stroke. 
     
     
         11 . The system of  claim 8 , wherein the at least one sensor of the load-cell device includes a RF transceiver configured to detect a RF transmission path between the load-cell device and a base receiving unit of the controller. 
     
     
         12 . The system of  claim 11 , wherein the controller is configured to monitor and use the detected RF transmission path to indicate a rotational position and/or a rotational rate of the rod string for controlling the pump operation of the pumpjack machine. 
     
     
         13 . A method for monitoring a rod string used in a pumpjack machine having a gear box and a prime mover, the method includes the steps of:
 providing a load-cell device including at least one sensor;   providing a controller configured to receive a signal from the load-cell device and control a pump operation of the pumpjack machine;   generating a position marker from the at least one sensor of the load-cell device;   communicating wirelessly between the load-cell device and the controller to transmit the generated position marker; and   controlling the pump operation of the pumpjack machine based on the generated position marker generated from the load-cell device.   
     
     
         14 . The method of  claim 13 , wherein the step of controlling the pump operation of the pumpjack machine includes the step of detecting an amount of slippage occurring between a motor output pulley of the prime mover and an input pulley of the gear box. 
     
     
         15 . The method of  claim 14 , wherein the step of controlling the pump operation of the pumpjack machine includes the step of determining a calculated position of the rod string based on the detected slippage. 
     
     
         16 . The method of  claim 15 , wherein the step of controlling the pump operation of the pumpjack machine includes the step of phasing the calculated position of the rod string at the location of the rod string determined by the generated position marker. 
     
     
         17 . The method of  claim 13 , wherein the step of providing the load-cell device includes the step of placing the load-cell device on the rod string. 
     
     
         18 . A method for monitoring a rod string used in a pumpjack machine having a polished rod connected to a top end of the rod string and a rod rotator installed at the polished rod, the method includes the steps of:
 providing a load-cell device including at least one sensor;   providing a controller configured to receive a signal from the load-cell device and control a pump operation of the pumpjack machine;   detecting a RF transmission path between the load-cell device and a base receiving unit of the controller; and   controlling the pump operation of the pumpjack machine based on the detected RF transmission path.   
     
     
         19 . The method of  claim 18 , wherein the step of controlling the pump operation of the pumpjack machine includes the step of monitoring the RF transmission path to indicate a rotational position and/or a rotational rate of the rod string. 
     
     
         20 . The method of  claim 18 , wherein the step of providing the load-cell device of the pumpjack machine includes the steps of attaching the load-cell device to the polished rod, and placing above the rod rotator and beneath a rod retaining clamp.