The function of 98898 Crank Assy for NOV Varco TDS11SA Top Drive

In petroleum drilling operations, the top drive system is unquestionably one of the most critical pieces of equipment on the entire rig. Among its many key components, the safety and reliability of the IBOP directly impact well control safety and the protection of personnel and property on site.

The NOV Varco TDS-11SA top drive is fitted with two ball-type IBOPs: an upper remotely operated valve and a lower manually operated valve, providing instant well control protection during drilling and tripping operations. The 98898 crank assembly is a key actuator component for the upper IBOP 110103-500 and 110103-502.

What is the 98898 External IBOP Crank Assembly?

The 98898 Crank Assembly, External, IBOP (OEM Part No. 98898) is an important part of the PH-75 Pipe Handler system on the NOV Varco TDS-11SA and TDS-9SA top drives, and is also used in the PH-50 torque stop assembly. In simple terms, it is the critical intermediary that converts the linear thrust of a hydraulic cylinder into a rotary motion to open or close the IBOP valve.

A complete 98898 crank assembly consists of the following core components:

Crank Housing

Crank Arm

Cam Follower

Roller Bearings

Working Principle

The working principle of the 98898 crank assembly reflects the elegance of mechanical transmission design: it skillfully converts the linear motion of a hydraulic cylinder into rotary motion, precisely controlling the 90° turn of the upper IBOP ball valve.

Specifically, when the driller operates the upper IBOP switch on the control console, the top drive system’s PLC sends signals to the corresponding solenoid valve, switching the hydraulic circuit. The hydraulic cylinder pushes the linkage, which drives the sliding sleeve inside the crank assembly up or down. The sliding sleeve’s motion is converted via an internal rocker arm assembly into a rotation of the plug valve, causing the ball to rotate 90° – opening or closing the internal blowout preventer.

The 98898 crank assembly has high mechanical efficiency. Under long-term exposure to extreme downhole pressures and high‑intensity operations, it consistently delivers stable torque output. At the same time, its roller bearings and lubrication system effectively reduce friction and wear between moving parts, extending the assembly’s service life.

Spare Parts Procurement

The 98898 crank assembly is available through well-established supply channels. Several professional oilfield equipment suppliers, such as Linhai Evergrow and GMS Supply, offer 98898 crank assemblies with performance equivalent to original parts. These products are ISO 9001 certified, kept in stock with short lead times, and backed by comprehensive after-sales support. For TDS-11SA users, the upper IBOP repair kit (Part No. 114859) is often stocked together with the 98898 crank assembly to facilitate on-site maintenance.

Conclusion

In the high risk, high investment world of oil drilling, the failure of any small component can trigger a chain reaction or even a major accident. The 98898 external IBOP crank assembly may seem unremarkable within the NOV Varco TDS-11SA top drive, but it plays an indispensable role in the well control safety line.

Understanding its structure and principle, implementing preventive maintenance, and paying attention to spare parts management will not only make the top drive more reliable but also provide an extra layer of safety for everyone on the rig floor. I hope this analysis is helpful to those who use or maintain the TDS-11SA top drive. If you encounter any difficult problems related to the crank assembly in actual operation, feel free to email emily@linhaievergrow.com and discuss!