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When Timing is Everything

JDR Level Winds with the Candy Differential

JDR is an innovator and leading provider of subsea technology and services for the oil, gas and renewable energy industries. Simply put, JDR’s products provide the delivery of power and control that is critical to subsea wells and renewable energy applications. Products from JDR include power cables, production umbilicals, intervention workover control systems (IWOCS), end terminations and other accessories.

jdr-level-winds-with-the-candy-differential-01Faced with the challenge of providing accurate spooling of cables, also referred to in the industry as “level wind,” JDR turned to Candy Controls and the Candy Differential for help. IWOCS incorporate umbilicals and these umbilicals are custom made cables that provide conduits for hydraulic fluids, process chemicals, electrical power and communication necessary to monitor and control the operation of subsea oil and gas wells. These cables can be up to 8500 feet long and can be stretched along the sea floor connecting multiple wells.  Due to the length of these cable assemblies, unwinding, and particularly rewinding can be a challenge. The umbilicals need to be aligned when reeled around the spool drum and if you have ever tried to wind a long garden hose you begin to understand just one of the many problems JDR helps solve for energy producers around the world.

Imagine a garden hose reeler. Now picture that on an enormous scale, with an 8,500-foot umbilical capacity, mounted on a sea-based rig and providing power and control to the well, or wells, below. Accurately spooling an umbilical not only requires maintaining a tight wrap, but also positioning the cable evenly across the width of the drum, creating a slight lag to the nominal spooling position. JDR incorporated a precision differential gearbox from Candy Controls to mechanically control the position of the umbilical cable as it is being reeled-in.

The Candy Differential is a phase-shifting gearbox that allows the output shaft position, or phase, to be changed relative to the input shaft, either statically or dynamically. The differential has three shafts; input, output and control shaft. When the control shaft is held stationary, the input and output shafts rotate at a 1:1 ratio, as if the gearbox is not even there. When the position or speed of the rotary process that is driven by the output shaft requires adjustment, a rotation can be applied to the control shaft creating the differential action. The rotation on the control shaft can be intermittent for rotary position control or constant for speed trimming the output shaft relative to the input.

jdr-level-winds-with-the-candy-differential - internalIn JDR’s reeler application, the Candy Differential is used to control the position of the level wind assembly relative to the drum. This assembly runs back and forth across the drum and has rollers over which the umbilical passes to help control position as the cable is being wound. The horizontal adjustment of the level wind assembly, which affects nominal cable wrap position, can be made while the drum is static or moving through the use of an air motor on the control shaft of the Candy Differential.

The reelers are designed and fabricated in JDR’s state-of-the-art manufacturing facility located in the United Kingdom. This is where JDR’s design team turned to the Candy Differential to assist with level winding. When asked of the benefits provided by the reeler design with the Candy Differential, the Design Manager, Umbilical Reeler Systems, spoke of its importance to help control level wind, quickly and efficiently, and doing so while the reeler drum is stationary or moving. Another benefit was the ease of installing Candy’s phase-shifting gearbox into JDR’s design. Perhaps the most significant benefit pointed out by the Design Manager, is the reduction in required reeler size as a result of the ability to more efficiently control spooling position. The Design Manager states, “We normally design drums with 20% excess capacity, however, by using the Candy gearbox with a powered override option, we can reduce the spare capacity to 10%, thus reducing the size of the drum, which also affects deck footprint.” Space on an off-shore rig comes at a premium, and JDR helps its customers by reducing the physical size of its equipment while not sacrificing umbilical capacity.

Energy is vital to modern life, it is an integral component of the world economy, and it has significant implications for the further advancement of technology and ultimately our standard of living. Producing energy more efficiently and more safely is absolutely critical and JDR helps its customers do just that. JDR is a world-class company and we at Candy Controls are proud of our association with JDR through the Candy Differential application on JDR’s umbilical reelers.

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