A typical application of a seat tight proportional flow control valve is the lowering and holding of loads such as those used in a forklift truck. The pressure compensator integrated into the valve compensates for any load changes, while the volume flow and thus the traverse speed of the hydraulic cylinder can be controlled very precisely and sensitively via the solenoid current. In the de-energised state, the valve closes tightly and thus the load can be held securely in the desired position. The proportional valve can continuously adjust volume flows between 0.5 l/min and 35 l/min via the solenoid current at an input pressure of max. 350 bar.
The possibility of a sensitive adjustment of the volume flow in the small-signal range can be seen by a slightly progressive valve characteristic. Combined with coated and precisely aligned valve parts, the specially designed armature tube leads to a very finely adjustable volume flow with low hysteresis. Due to the hardened and polished valve components, only minimal wear occurs and thus a long service life is guaranteed. Also, the zinc-nickel coated valve outer parts ensure a high level of corrosion protection.
Further, the valve can also be opened manually using integrated manual emergency actuation, even without solenoid current. The normally closed valve with the designation QSPPU10 is available as a 2-way function with a U10 cavity according to the Wandfluh standard and can be operated with all Wandfluh standard and special solenoid coils of size 35 mm. A solenoid coil with integrated electronics is also available and enables the setting and adjusting of the valve at the factory.
