During maintenance and installation operations on machinery or their components, it is sometimes necessary to keep the load suspended for hours and ensure its complete «immobility.» Despite the apparent obviousness of this requirement, the block valves commonly installed on the boom cylinders exhibit minimal leaks, equivalent to a few drops per minute. Even the slightest leakage can affect the stability of the suspended load and therefore the outcome of the ongoing intervention. In light of these considerations, Manitex Valla has developed a unique and innovative solution: EHV is a double zero leakage block valve system, specifically designed for Pick&Carry cranes, in collaboration with Valvole Italia, a leader in this field.
The effectiveness of this solution has been demonstrated through rigorous testing, ensuring complete load stability at any height. The valve designed for this system is distinguished by its internal redundancy in load-holding functionality. Compared to traditional solutions that use a single overcenter with mechanical seal between ground components, this configuration employs two overcenters mounted on a flanged block on the cylinder, arranged in series on the load support line.
This approach significantly enhances load stability over time and provides superior performance, even in unforeseen situations of oil contamination. Additionally, the valve is equipped with a damped opening system that, in synergy with the machine’s control system, ensures precise positioning and smooth movement, even at low speeds, making it ideal for precision work.