New Holland CSX7000 - Stack Valve Operation and Description

DISTRIBUTIONSYSTEMS-PRIMARYHYDRAULICPOWERSYSTEM
Stackvalve-Dynamicdescription
Ifallvalvesareinthe"0"position,then:
Thevalves(13),(15),(17),(21)and(28),(RefertoStackvalve-Staticdescription(A.10.A))areclosed,which
meansthattheoilcannotowthroughthesevalves.
Thepressureraisesat(7b),(27b),untiltheloadsensingspoolispushedopenagainstspringpressure(deltaP=3
bar)andthereturnpressureinthepilotline(7a),(27a).Nowpumpoilowsintothereturnlineatstandbypressure.
Whenactivatingthelateraloatcontrolspools(ifinstalled),thehydrauliccylinderpressure(pumppressuremeasured
afterthespoolrestriction)ispresentinthepilotline(7a),(27a)andclosestheloadsensingspool.Theoilpressureis
availablefortheactivatedcontrolspool(s).
Whenthepumppressurereachesthecylinderpressure(+3bar),theloadsensingspoolispushedopen.Thenec-
essaryamountofoilwillowtothecontrolspoolattheneededpressure.Excessoilisdumpedintothereturnline.
Whenactivatingvalveswithoutdirectloadsensing,(13),(15),(17)and(21),thepilotvalve(42)isactivatedaswellto
connectthepressurelinewiththeloadsensinglineandclosestheloadsensingspool.Theoilpressureisavailable
fortheactivatedcontrolspool(s).
Whenthepumppressurereachesthecylinderpressure(+3bar),theloadsensingspoolispushedopen.Thenec-
essaryamountofoilwillowtothecontrolspoolattheneededpressure.Excessoilisdumpedintothereturnline.
Whenthecylinderreachesendofstroke,thesystempressurestartstoraise.Whenthepilotpressurereaches207
barforthemainstackvalve(175barforthelateraloatstackvalve)thepressurereliefvalveispushedopenand
systempressureislimitedto210bar(207+3bar)
Theloadsensinglockoutvalveensuresthatpilotpressurecannotescapeintothereturn.
RNPH08CS0008A0B1
84210989A24/04/2009
A.10.A/
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