Accumulator or High Flow Pump Unloading Valve, with Dual Unloading/Reloading Pressure Adjustments

This Unique pressure control valve was developed in Western Europe where power costs are much higher and there is considerably more emphasis placed on efficient hydraulic systems that save power.  Thus, accumulators and high/low pump power units are more often required. Data sheet: 2.1-950E, and 2.1-970E

The main feature of the Wandfluh Accumulator or Pump Unloading Valve is that it offers adjustable pressure control for both the unloading (dump pump flow to Tank) and reloading (rebuild system pressure) functions.  Most unloading valve circuits offer only an unloading pressure adjustment and a fixed not readily adjustable reloading pressure.  The difference between the unloading and reloading pressure is example, typical unload-reload ratio for clamping circuits (hold at high pressure) is 90%; an example would be unload at 1000psi, reload at 900psi, but this is an uncommonly high ratio for many pressure holding circuits, and not practical for fast approach slow feed circuits where there is time to make up stored low pressure volume at low power input, or demand for holding pressure is sporadic and used only for emergencies.  Only one Wandfluh dual Adjustment Unloading valve is required for a wide variety of accumulator pressure control applications, and the desired unload-reload ratio can be re adjusted in the field if unload-reload requirements change.

Other important features are:
1.  Internal spook leakage is extremely low (see page 2 of data page) and thus do net bleed down the charged accumulator quickly and the pressure or charging pump does not have to operate often.
2.  The valve comes in 2 sizes, NG6 (NFPA D03) and NG10 (NFPA d05, and mounts on standard NFPA sub-plates.
3.  The NG6 size can used to pilot larger DIN type poppet vlaves that may require a variety of pilot pressures and flow rates depending on the ratio choices of different sizes of DIN poppet valves. 
4.  Both sizes are rated continuous duty to 5000 psi, peak to 5800 psi. 
5.  All working parts are of steel, sub-plates can be provided in steel or high grade aluminum, pressure adjustment valves have lock nuts; for fine resolution, 3 pressure adjustment ranges are offered as standard, seals are Buna N, or Viton; EP (ethelene propalene) on special quote.
6.  If valves are to be exposed to wet, humid, icy conditions, or salt water, ask us for quotation on CRES surface finishes or Type 316 L stainless steel external parts.

Ed V. Askey