Almo Manifold & Tool Co., East Tawas, Mich., offers a slip-in cartridge-style, solenoid-operated loading relief valve that conforms to the DIN 24342 (ISO 7368) standard. The design promises faster response and lower leakage rates than larger conventional spool-type valves. These valves accommodate pressures to 5,000 psi and maximum flow from 50 to more than 700 gpm.
The valve incorporates a single-cavity manifold block (with Code-61 or Code-62 flange mounting) that holds a spring-biased poppet-valve insert. A relief cover that mounts over the block contains an adjustable screw-in cartridge relief valve and a two-position, three-way directional-control valve.
While the solenoid is deenergized, pressure on the bottom surface of the poppet overcomes the spring force at the top. The poppet shifts to open a flow path to tank. Pump flow passes freely with minimal power loss.
To load the system’s pump, the solenoid is energized. Pressure then builds in the manifold chamber above the poppet and combines with the spring force to shift the poppet to its closed position. The cartridge-style relief valve in the cover now takes over to maintain the pressure above the poppet at the relief setting. (Orifices in the cover limit flow to the relatively small relief valve.) Any excess pressure above the poppet exhausts through the cartridge relief.
If system pressure below the poppet exceeds the relief setting, the force it generates overcomes the spring and pressure force above the poppet. The poppet then shifts open again to pass pump flow directly to tank.
For more information call Almo Manifold & Tool at (877) 256-6669, or visit www.almomanifold.com.