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 be contained in 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 applications, 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 and has the freedom to create hydraulic solutions that provide the perfect fit for the application.
Case In Point: Casinjac
Superior Fabrication Inc. (SFI; Elk City, OK) manufactures production equipment for the oil and gas industry. Among its product offerings are hydraulic jacks capable of lifting drill strings up to one 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,” said 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 Inc. (Yukon, OK) 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. If 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,” said 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,” said Cansler. “With other power units, different styles of pumps can have fluctuations. They might build up to 3000 lb of pressure, for example, but could drop off to 2500 lb before building back up again.”
“With the Casinjac, you want a nice easy, flow of hydraulic oil going to that jack,” he added.
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 lb of drill-string pipe, you can pre-set the pressure setting. A lot of the other HPUs do not allow you to do that,” said Cansler.
Although the Casinjac can be powered by other manufacturers’ HPUs, it can come at some risk of efficiency loss. In one case, 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. They allow you more control of the operation you will be performing on the well,” said Cansler.
Mobile Irrigation Equipment
For Destry Suthers, vice president of Knutson Irrigation Design LLC (Yukon, OK), an off-the-shelf, assembled solution was not sufficient for the company’s portable irrigation equipment that utilized hydraulic systems.
Since 1981, Knutson Irrigation has been a distributor of unique irrigation, turf, and hobby farm maintenance products, including electric gas and diesel pumping solutions for applications in many different industries.
The company required a custom solution for a specific piece of patented equipment it manufactures.
“We are able to outsource the hydraulic piece of the puzzle while we worked on other aspects of the project,” said Suthers, who also turned to Devine Industrial Systems. “That allowed us to work on things that were more in our wheelhouse.
“They can take whatever your application is and engineer and design a system that will have the capacity to operate whatever it is you are going to power,” Suthers continued. “There is a fair amount of design that goes into that.”
Suthers added that for larger hydraulic systems, the sizing of the HPU should match the size of the unit.
“An off-the-shelf unit may not be sized to exactly what you need,” explained Suthers. “Devine Industrial Systems’ forte is laying out the package so that it works within certain space constraints, such as a portable enclosure, skid or trailer.”
Another advantage of going with a true manufacturer with full fabrication capabilities is the customization of the mobile equipment’s controls. Depending on the application, the controls could be manual, electric or even electronic for remote control.
“They can put the operator controls wherever you want it so it’s nice, convenient, and easy to use,” said Suthers. “They can basically build it however you need to build it.”