CR
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Catalog excerpts

Switch unit type CR with an automatic pre-relieving feature (shock-free decompression) for the control of bottom-ram presses with dual stage drive either manual or solenoid actuation Pressure pmax = 400 bar (high pressure) = 60 bar (low pressure) Flow Qmax General information ' Compression cycle Combines both pump delivery flows for the rapid approach cycle. Fully automatic switch-over of the low-pressure pump to idle circulation, when the pressure equals or exceeds the low-pressure value selected for the rapid approach cycle. Both pressure stages are safeguarded by a built-in high pressure limiting valve and by the pressure limiting function of the low-pressure switch-over valve. ' Maintaining the pressure 2/2-way valves, check valves and all other functional parts show zero leakage while connected to consumer port A. An additional pump is not required during the compression interval. The two-stage pump is cut-off by the pressure switch unit when the compression pressure is attained (see pamphlet 5440). Prerequisite: Press cylinders with no leakage. ' Opening the press Type Electrical actuation of the pilot-operated solenoid valve initiates a soft pressure reduction (decompression) down to approx. 10 bar. This occurs without any pressure surges, thus protecting the unit from damage, and then passes over into a rapid and complete opening of the 2/2-way valve which also occurs without any pressure surges. Optimum lowering rates are attained from a tare or deadweight pressure of approx. 2 bar or more. When the hand lever is thrown into position a , the operator will first distinctly feel a straining point at which a pre-relieving valve connected in parallel to the return valve opens, thereby effecting shock-free decompression. The straining point disappears upon completion of decompression and the hand lever can be moved until it stops, thereby opening the return line completely. The deadweight pressure should be higher than 0.5 bar. HAWE HYDRAULIK SE STREITFELDSTR. 25 • 81673 MÜNCHEN D 7150 Switch unit type CR September 1999-02

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Available versions, main data CR 4 M - WG 230 - 400/60 CR 4 H Pressure setting (bar): Low pressure High pressure Table 1: Basic type and size Application Table 2: Actuation / mode Electrical Bottom-ram presses with deadweight return Applies to CR 4 and CR 5 Solenoid, conf. VDE 0580 Coding Flow Qmax (lpm) High pressure (HP): = 400 bar Low pressure (NP): = (0) ... 60 bar Mass (weight) Deadweight pressure Switching On time (ms) Off Manual Hand lever (only for CR 4!) H Only little manual force necessary Available with a fixed setting only, specify the desired pressure setting when ordering; see...

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Unit dimensions All dimension in mm and subject to change without notice! Type CR 4 M.. and CR 5 M.. Manual emergency operation M10, 12 deep in front and back (thread), thru-hole Type Press the emerg. bolt inwardly with an appropriate tooI (screw driver, etc.), max. operating force is 150 Nm. The manual emergency function can be put out of commission by inserting a screw M3 x 5 DIN 921 M10, 12 deep in front and back (thread), thru-hole Subsequent pressure adjustment (always check using a manometer) monitored by a pressure gange and pumps running High pressure adjustment possible after...

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Typical circuit diagrams Bottom-ram press with CR 4 M..- or CR 5 M..- control (CR 4 H analogously) Cycle chart for this circuit Cycle Platen movement Closure (rapid approach) Pressure build-up final press. Automatic relief of 1-3 low pressure pump M off Pressure mainten. Pressure switch in cycle 2 - end, e.g. also starts timer for cycle 3 By pressing a button or expiration of timer Open, stop By limit switch, button release, etc. Start by pushing button Two-stage pump Type RZ acc. to D 6910 H Type MP acc. to D 7200 H In the CR 4 H control, cycles 1 (hand lever in "close" position) to 3 are...

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