Fixed-orifice, flow fuse valve

NO! Flow fuses are meant to prevent the uncontrolled movement of an actuator in case of hose failure. To avoid false tripping they must be set above the typical system flow, usually 50% above. On a 4 gpm (15 L/min.) circuit the flow fuse may need to be set at 6 gpm (23 L/min.) to avoid false tripping. Hoses do not normally fail totally, they spring a leak. If the hose springs a 5.5 gpm (21 L/min.) leak the flow fuse will not trip. 5.5 gpm (21 L/min.) of hydraulic fluid will feed a fire that would heat a small town in Ohio (Denmark) in January!

It is very, very difficult to predict the transient flows in a system. We say at least 25% above maximum normal system flow and should say 50%. Don’t back yourself into a corner by sizing a flow fuse at the top end of its range unless you can test it. If you have an FQCA in a 4 gpm (15 L/min.) circuit, set at 6 gpm (23 L/min.) and it false trips, you are out of luck. Select an FQEA and leave yourself some room for tuning.

What's wrong is that every time you start to lower your load, you get a flow transient that exceeds the setting of the flow fuse and trips it. Sun's flow fuses are very consistent and very fast.

There are exactly 250 Sun drops in a cubic inch or 15 in a cc.

NO! Flow fuses are meant to prevent the uncontrolled movement of an actuator in case of hose failure.