For OEMs that design and build equipment or machinery, the hydraulic systems that drive the elements that lift, push, pull, drill or dig are often outsourced so as to maintain focus on their core competency – the rest of the system.
However, sourcing the ideal hydraulic solution can present several challenges. To ensure optimum performance, the hydraulic power unit (HPU) must be designed to meet the specific requirements of the application. Complicating matters, these systems often must fit within specific, unique dimensions to fit a specific enclosure, skid or trailer.
When this occurs, OEMs often turn to more vertically integrated custom manufacturers that can design and build such systems from the ground up. By doing so, the hydraulic system can be optimized to improve performance, efficiency, and long-term reliable service of OEM equipment in the field.
Outsourcing Hydraulic Systems
Hydraulic systems are largely comprised of standard components that include a prime mover (diesel engine or electric motor) along with pumps, valves, actuators, reservoirs, accumulators, filters and other parts.
However, in the industry, there is delineation between those that manufacture – or perhaps more appropriately stated, assemble – such systems and vertically integrated fabricators that engineer and build the system from the main structural steel components through to the required controls.
In some cases, off-the-shelf or assembled systems are available from large component product distributors. With a heavy leaning towards incorporating the parts/products in their portfolio, these distributors often farm out the fabrication of the metal structures as well as other key sub-assemblies.
Although this may be sufficient for some application, it eliminates some of the flexibility to adapt or fine tune the design. In some cases, component parts may be too large or not rated for the application, leading to premature failure.
A true, vertically integrated manufacturer, on the other hand, can fabricate from raw steel the main structure and with no predilection to specific brands has the freedom to create hydraulic solutions that provide the perfect fit for the application.
Case in point: Casinjac
Superior Fabrication Inc. (SFI) manufactures production equipment for the oil and gas industry. Among its product offerings are hydraulic jacks capable of lifting drill strings up to 1 million pounds in weight. The Casinjac is often used for plug abandonment (P & A) of oil and gas wells to extract the casing.
The process of removing the wellhead slips often requires the pipe string be lifted to take the string weight off the wellhead slips. When the force required to move the pipe upward is greater than the safe pull force of a work-over or drilling rig, the Casinjac can be used.
Factors contributing to the required lift force include the pipe being stuck at a shallow depth, the work-over or drilling rig is not rigged up over the hole, the wellhead slips are binding in the wellhead or the pull sub is not straight.
To lift the immense weight, each Casinjac requires a hydraulic power source and the performance of the jack depends on the capabilities of that power source.
“We’ve designed our hydraulic power units with optimum performance of the jacks in mind,” says Joe Cansler, head of the Casinjac division at SFI. “Each particular potential use of the Casinjac has its own horsepower, flow, and pressure requirements.”
Currently, SFI offers three standard HPUs. The units were originally designed by Devine Industrial Systems for the Casinjac and are still manufactured by them today. Founded in October 2004, Devine Industrial Systems designs and creates hydraulic power systems as well as sub-assembly parts. As requested, the company can also provide custom units to SFI.
“The hydraulics for us are not a high-quantity type of manufacturing so rather than us jumping into it and warehousing the parts and putting the staff together, it just made sense to continue to outsource it to Devine Industrial Systems,” says Cansler.
Critical design features play a big part in the function of the unit. Each HPU utilizes pressure-compensated hydraulic pumps that allow the jacks to exert a steady, continuous pull force.
“The hydraulic power units we supply utilize a pressure-compensated piston pump that delivers a constant, even flow of hydraulic pressure to the jack,” says Cansler. “With other power units, different styles of pumps can have fluctuations. They might build up to 3,000 lbs of pressure, for example, but could drop off to 2,500 pounds before building back up again.”
“With the Casinjac, you want a nice easy, flow of hydraulic oil going to that jack,” he adds.
The operational controls engineered as part of the system also provide the ability to increase or decrease pressure without being engaged in the jacks.
“If you know you need to pick up 200,000 pounds of drill-string pipe, you can pre-set the pressure setting. A lot of the other HPUs do not allow you to do that,” says Cansler.
Although the Casinjac can be powered by other manufacturers’ HPUs, it can come at some risk of loss of efficiency. In one specific example, a customer utilized a unit that failed in the field. In examining it, some of the components were not rated for the pressures applied.
“We always make sure the customer understands that our power units are the only ones designed to officially and effectively operate our equipment in the safest manner and it allows you more control of the operation you will be performing on the well,” says Cansler.
By Jeff Elliott