If you plan on upgrading conventional circuits to hydraulic integrated circuits, be sure to avoid pitfalls that may not be all that apparent.

Integrated circuits are one of the foundations of modern technology. The electronic variety is at the heart of everything from smart coffee makers to supercomputers, and the hydraulic variety is well on its way to becoming equally indispensable across a wide range of applications. Although the comparison may seem a bit forced at first, the similarities between the two technologies and the reasons for their explosive growth over the last few decades are remarkable.

Both, for example, are products of a quest to combine higher performance with improved reliability in ever smaller physical packages. Both seek to achieve these goals by packing more capabilities into individual components while minimizing the size of the physical connections between them. Furthermore, both are well on their way to replacing the older technologies from which they sprang — and for many of the same reasons.

Traditional hydraulic circuits consist of line-mounted valves and other components linked together through tubes and hoses. Sometimes they are attached to a common plate, and other times they are distributed throughout a system.

Designers later began mounting valves onto subplates to make them easier to maintain and change when necessary. Later still, the subplates were bolted to manifolds to create even more compact control assemblies. Connections got shorter, leakage was reduced, and systems became more compact, but everything was still essentially bolted together in an ad-hoc arrangement.

The age of modular circuit design
While that trend was evolving, a revolution was taking place in valve design. Screw-in cartridge valves made their first appearance on agricultural equipment in the late 1960s. As the name implies, these valves are screwed directly into a manifold, eliminating the traditional cast iron valve body completely. Initially limited to basic functions, cartridge valves quickly grew in performance and sophistication to mirror many of the capabilities of traditional valves.

The merging of the two trends is represented by what Eaton calls modular circuit design, a technology that consolidates most or all of the control functions required in a vehicle or device into a single, compact manifold populated primarily by cartridge valves with only a few surface-mounted valves. Other manufacturers have their own terminology, but regardless of what they’re called, these hydraulic integrated circuits are well on their way to becoming the standard solution for hydraulic control systems in the majority of both mobile and stationary applications.

Hydraulic integrated circuits offer several advantages, such as:

• Short flow paths and customized designs can provide higher performance than traditional line-mounted and subplate-mounted systems can.

• Control assemblies are extremely compact, inherently vibration resistant, and highly reliable.

• Installation is simplified because fewer hydraulic and electrical connections are required. Hydraulic integrated circuits often can be attached directly to steering units, pumps, and cylinders to reduce both overall system complexity and installation because fewer connections need to be made.

• Opportunities for leakage are dramatically reduced because all control interconnections and most of the moving valve components are inside the manifold block. Only connections for input and return lines, and links to cylinders, motors, and other actuators are required.

• Identical custom units with specialized capabilities are easily and economically produced in quantity. Mounting, plumbing, and wiring all can be standardized.

• Single-sourcing simplifies procurement processing and reduces overall system costs. This can also mean leveraging complementary technologies, including industrial and mobile valves, fittings, and fluid conveyance to produce cost-effective solutions.