SUN HYDRAULICS Ventable, pilot-operated, balanced piston relief valve – before check (HVCALAN)

The ventable relief-before-check cartridge is a CavitySaver™ (multi-function) valve incorporating a ventable, pilot-operated, balanced piston relief tee’d in before a check function. When the pressure at the inlet (port 2) reaches the relief valve setting, the valve starts to open to tank (port 3), throttling flow to regulate the pressure. The check valve flow is from the inlet (port 2) to the system port (port1). The valve includes a vent port (port 4) that connects between the main piston and pilot stage to provide for remote control by other pilot or 2-way valves.

These valves are accurate, have low pressure rise vs. flow, are smooth, quiet, and are moderately fast.

• Note! This valve deviates from Sun’s normal flow path for relief valves. It is probably not useable in current Sun relief manifolds.
• Minimum setting is 75 psi (5 bar) for all spring ranges.
• Back pressure at port 3 (tank) is directly additive to the valve setting at a 1:1 ratio.
• The check portion of the valve has a maximum leakage rate of less than 1 drop/minute (0,07 cc/min).