Among all hydraulic directional-control valves used in mobile equipment applications, the spool valve is arguably the most popular, and sectional types allow for flexible construction. The VD8A directional-control valve from Salami SpA, Modena, Italy, has a modular construction and consists of an inlet section, up to eight working modules and an outlet section. All the elements are secured in one block by means of tie-rods.
The company’s VD8A/Z version is a sectional mobile control valve with integrated electrohydraulic PWM proportional control. It has a cast-iron body with hardened steel spools that are nickel plated for enhanced corrosion resistance. Several types of available spools include double- and single-acting, spool motor and regenerative position. Electrohydraulic open loop on-off and proportional control are offered with 12 or 24 Vdc. It also has power-beyond or high-pressure carry over (HPCO) capabilities. The VD8A/Z includes parallel circuits with a load check valve on every section, and an emergency command button.
Inlet valves include direct, pilot and unload versions, and auxiliary valves are overload, anticavitation, overload and anticavitation, and conversion options. Available ports have threads such as BSP, BSPF-JIS B, metric ISO 262, metric ISO 6149, or SAE UN-UNF.
The VD8A/Z offers nominal flow of 75 l/min (20 gpm) with maximum flow of 90 l/min (24 gpm). Operating pressure ratings are 315 bar (4,600 psi) nominal and 350 bar (5,070 psi) maximum.