Although the benefits of hydraulic integrated circuits (HICs) are not as dramatic as those in the electronics world, they still can substantially reduce the size, complexity, and overall cost of hydraulic systems. Furthermore, HICs exhibit additional advantages that go beyond these benefits.
An HIC consists of a manifold containing multiple pressure-, directional-, and even proportional-control valves. In extreme cases, an HIC may even contain pumps, filters, actuators, or any combination of these to form a completely self-contained hydraulic system. This has become a growing trend in hydraulics by using a variable-speed electric motor to drive the hydraulic pump. Most HICs, however, consist of a manifold containing inlet and outlet ports, cartridge and subplate mounted valves (or both), and a network of internal passages that route hydraulic fluid through branch circuits of the hydraulic system.
Realizing the Benefits
Traditional hydraulic systems use hose and metal tubing to route hydraulic fluid from a hydraulic power unit (HPU) to a variety of valves and actuators, and back to the HPU. With an HIC, hose and tubing still routes fluid from the HPU to a variety of valves, but most of these valves may be contained within a single manifold tucked away in an available space on a machine.
With a conventional system, the line-mounted valves take up more space than cartridge valves, so they may end up being installed at many different locations throughout a machine. This complicates troubleshooting and maintenance and can require installing hoses in locations where they could be struck by foreign objects or otherwise damaged by ambient conditions.
Although the time to design the HIC and machine the manifold are additional expenses for the initial system, this cost usually is more than offset by the lower cost of cartridge valves, reduction in the cost of required hose, tubing, and fittings, and the much lower cost of assembly and installation. This means benefits like a lighter, more compact system and easier maintenance come at no additional cost.
Troubleshooting can be easier with an HIC because multiple valves, switches, and test points may all be located within close proximity to each other, instead of being located throughout a machine. Furthermore, eliminating hose and tubing assemblies and fittings reduces the potential for leakage and component failure, so less maintenance is required and reliability is improved.
Don’t Settle for Breaking Even
However, don’t expect to integrate all in-line valves into HICs. The break-even point must be considered when making a switch to integrated circuits. The financial advantage to using HICs depends on quantity—but not in the usual sense that unit cost decreases as the number of units increases.
From the aspect of quantity, mining equipment, for example, might not seem to be a viable application because only a few complete units of a particular model machine are manufactured annually. But HICs are effective here because one machine—such as a roof bolter—contains so many components that can be incorporated, integrated, or eliminated.
An equipment builder may need a specific HIC only two or three times a year, so there’s no way a custom-made block will be more economical than off-the-shelf components. However, the installed cost of the block with the many cartridge valves can be much less than the numerous individual valves, fittings, hose, and the cost to install them would’ve been. What’s more, the HIC adds even greater value throughout the life of the machine because a cartridge valve can be replaced at a fraction of the cost of its in-line counterpart—and without even having to disconnect a single hose!
Moreover, real estate on mining equipment has become a real focus with OEMs because of ever-increasing options required on equipment. That makes HICs and their benefits even more attractive to an OEM’s design engineers. Couple that with the movement to standardization for global design, and you more opportunities than ever.