Concentric-F20LS/F30LS LOADSENSE PUMPS-2011-6 3 How the F20LS and F30LS Pumps Operate Every hydraulic application has two known operating conditions - running (when hydraulic flow is required) and standby (when no hydraulic flow is required). Running Condition: In the running condition, the F20LS/F30LS load sensing element continuously monitors the output flow required for the system load demand. The pump alters its flow at the pump and matches the system load demand and delivers the exact flow required. Flow regulation at the pump eliminates efficiency losses associated with alternative systems which alter flow at the directional valve and regulate system pressure with a system relief valve. Standby Condition: In the standby condition, the load sensing element senses a zero demand condition and unloads all flow directly to the system's reservoir. In the standby condition, flow is unloaded at approximately 20 PSI, hence, greatly reducing horsepower consumption and system heat. The chart below illustrates the horsepower conservation advantages of the F20LS/F30LS pump when compared to the common alternative system designs of a piston pump and a standard open center valve/gear pump combination. NOTE: In the standby condition, piston pumps operate at 200-500 PSI and produce 1-2 GPM for internal lubrication purposes. This condition results in higher horsepower consumption than the F20LS / F30LS at standby. Where to Apply the F20LS and F30LS Pumps Mobile Applications The F20LS and F30LS are best applied in mobile applications where the vehicle duty cycle is concentrated in either the full speed or the standby condition. The F20LS and F30LS are ideal choices for vehicles which have extended transport or "roading" modes. Examples of these types of vehicles would include tractors, wheel loaders, snow and ice removal trucks and many others. Significant horsepower savings as described above is achieved during the standby mode. The F20LS / F30LS may not have advantages over the piston pump in applications where flow must be continuously "metered", consequently the selection of these pumps is dependent upon the application. Industrial Applications The F20LS and F30LS can also be used in many industrial type hydraulic applications to simplify and cost reduce traditional circuits. General load sensing, accumulator unload, vented relief valve, multiple relief valve and other types of circuits can all be simplified and cost reduced by using the F20LS and F30LS pumps. These circuits typically use expensive unloader or vented relief valves and the F20LS and F30LS can reduce system costs by 50% or more by incorporating the load sensing feature in the pump and using significantly less expensive standard directional control valves. (Associated installation costs are also reduced because of the circuit simplification achieved by using the F20LS and F30LS along with standard directional control valving.) Standby Condition HP Consumption (Actual Consumption for 2.77-2.94 Cubic Inch Pumps) 0 1 2 3 4 5 6 F20LS (600 RPM) F20LS (2800 RPM) PISTON PUMP (600 RPM) PISTON PUMP (2800 RPM) STD. OPEN CENTER (600 RPM) STD. OPEN CENTER (2800 RPM) (In Horsepower) quality products for mechanical & fluid power ~ jbj Techniques Limited, www.jbj.co.uk UK distributor for Concentric Hydraulics
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