Often industries develop the proper tool for a particular task. In the case of sucker rod make up the industry took from existing technologies and the “sucker rod tong” was born. A conventional sucker rod tong typically consists of a large displacement hydraulic motor driving a gear train that rotates the upper rod until the hydraulic pressure driving the tong is relieved over a hydraulic relief valve. That valve has a Deadband that is affected by temperature, pressure, flow, and oil viscosity resulting in improperly made up connections. It is for this reason that all industry tongs estimate their makeup based on speed and torque. The API Recommended Practice 11BR for Care and Handling of Sucker Rods states:
“as a result, applied torque has not proven to be the most accurate, nor the most practical means of measuring the preload stress level in a sucker rod joint”
Thus the recommended practice to properly make up sucker rods is Circumferential Displacement or CD. The recommended method of reaching CD involves rotating the sucker rod connection to shoulder (where the threads bottom out and usually a small tap with a rod wrench), then “carding” the rod OEM provided card. Marks are drawn vertically on the coupling and the rod connection that will be made up. Then the operator moves the top line the proper CD (matches to the bottom line) and now the connection is properly made.
*For this example we are leaving out proper rod prep, cleaning the threads, lubrication, etc.
The CD Rod Tong™ by Automated Rig Technologies Ltd. correctly makes up the rod connection every time by rotating the rod to shoulder, stalling at approx 60 ft-lbs, and then moving with a linear actuator to the correct user set CD. The CD Rod Tong™ makes the connection correctly every time!
The CD Rod Tong™ can be used in the field to make up connections perfectly and can be used in a plant application to correctly make up one side of the coupling prior to heading the field. Our RodIQ™ System will data log each connection and report to you and your client that their string was made up to OEM specifications.