With the introduction of Tier 4 engine emissions standards, the conventional wisdom of bigger meaning better has been jettisoned. As OEMs find themselves having to make more efficient use of their available horsepower, the demand has grown for compact and “tune-able” control options.
To give system designers a superior level of control with less pump flow and pressure drop, HydraForce has introduced a line of multi-function cartridge valves that enable more compact circuit designs without compromising on power and performance. HydraForce will be highlighting these new valves at its IFPE Booth 80930.
By consolidating multiple control system functions into a single cartridge, HydraForce has created many clever and compact valve solutions including combined system relief and on-off control, system bypass and flow regulation, and electrohydraulic valves with integral load sensing and load holding capabilities.
“By pushing the boundaries of computational fluid dynamics and other modeling software, we’ve been able to optimize the internal pressure dynamics and flow capacity of our valves while minimizing their actual size,” said Ron Morgenson, VP of Worldwide Technology at HydraForce.
The lineup now includes more than two dozen valve choices, encompassing electrohydraulic and mechanical flow, direction and pressure controls that can handle flow rates up to 303 lpm (80 gpm) and continuous operating pressures up to 350 bar (5075 psi).
The latest in the series of multi-function valves are the HSPEC valves which combine an electrohydraulic flow control valve with integral pressure compensation. There are two variations; one model features a post pressure compensating element that enables flow sharing, while the other features a load holding compensator that is ideal for stable lifting and lowering operations. Both models are available in three flow ranges that can satisfy flow demands from 0 to 32 lpm (9 gpm), 0 to 70 lpm (18 gpm) and 0 to 120 lpm (35 gpm) respectively.
Applications for HSPEC Technology
The HSPEC-30 valve provides the functionality that would otherwise require three separate cartridges. In a single cavity, it combines an electro-proportional flow control valve, a post-pressure compensated logic element, and load sense check valve. This new breed of multi-function valves is driving down the size of manifolds, giving machine designers the freedom and flexibility to locate the manifold where it makes the most sense. Whether the hydraulic circuit is packaged in a single centralized manifold, or is distributed and directly mounted to a hydraulic actuator, HSPEC technology provides the machine designer with uncompromising flexibility and ensures a more robust and responsive solution for machine control.
The HSPEC-30 valve enables “tune-able” directional control circuits in a way that cannot be accomplished with traditional options. With three sizes to choose from, the optimal cartridge size can be selected for the exact flow requirements of the application. With the freedom to mix and match cartridges with different flow ratings, directional control circuits can yield significant improvements in system response, flow control, and metering resolution.
The serviceability aspect of cartridge valve-based circuits is often overlooked. While it may take hours to repair or service a conventional stack-type directional control valve, it takes only minutes to remove and replace a cartridge valve. When servicing a cartridge valve-based circuit, the loss of hydraulic fluid and introduction of contaminants are also greatly reduced. Pairing a function with an optimally-sized control valve and avoiding depot-level maintenance on a directional control valve can be a boon to productivity.
An ideal application for the HSPEC-30 valve is a flow-sharing directional control circuit. A cartridge valve-based directional control circuit provides independent control of meter-in and meter-out flow logic.
By using the HSPEC-30 for the meter-in side of flow control, the flow-sharing benefits associated with post-pressure compensation allow precise motion control of a hydraulic motor or cylinder. Cartridge valve-based directional control circuits also have the added advantage in how they can be packaged. Although a single centralized type manifold is most common, a cartridge valve-based directional control circuit can be distributed and directly flanged to each hydraulic actuator; a feat not possible using conventional spool valve technology.
What goes up must come down
The HSPEC-34 replaces three valves as it combines the functionality of an electro-proportional flow control valve, a pressure compensating logic element, and a load-holding valve. This new family of multi-function valves was designed to provide superior load-holding characteristics, while allowing for precise and stable flow control. An ideal application for the HSPEC-34 valves are boom control circuits that benefit from the ability to selectively choose between power-down and gravity-assisted lowering. By using the boom’s structurally induced load pressure, the HSPEC-34 harnesses the natural force of gravity and provides smooth and stable lowering. With an emphasis toward increased efficiency, the HSPEC-34 has the potential to convert gravity-assist lowering into significant fuel savings.
As a result of extensive machine testing in the field, HydraForce documented a 22% increase in fuel efficiency, when using a gravity-lower circuit over a conventional power-down / counter-balance- valve- equipped boom control circuit. This equates to a fuel savings of 4 l (1 gal) of fuel per hour when running a machine through a typical boom up/down work cycle.