Frequently Asked Questions
You say your valves leak 5 drops/min. How can I keep my load from drifting?
The 5 drops/min. are at the point of reseat which is 85% of cracking pressure. If the valve is set correctly it will never see a load that is higher than 77% of cracking (1/1.3). At this pressure, in a typical system the counterbalance can be considered a zero leak device. Using counterbalance valves to prevent drift is an accepted and common practice on almost all manlifts and hydraulically operated cranes. If a load drifts because of the counterbalance valve, the seat has probably been damaged and the valve should be replaced.