Unic URW295CR - Oil Flow During Unloading

（１０−３）
10.3Oilflowinthein‑outbody
whenunloading
Workingpressure
ofpumpismaintained
at1Mpaorless
Emergencyscrew
Secondary
pressure
Spool
Core
Mainrelief
valve
Tank
Whenelectriccurrentflowsthroughtheunloadingsolenoid,
thecoreinthesolenoidismagnetized.
Magnetizedcoreallowsthespooltomovetotherighttoleadmain
reliefsecondarypressuretothetank.
Mainvalveopenstoreturnalltheoilfedoutofthepumptothetank.
Pressureinthecircuitatthispointis1Mpaorlessandtheback‑
pressurevalveandthepressureregulatorvalveareclosed.
Lockingwiththespoolintheunloadingsolenoidconnectedtothetank
allowsallthecranefunctionstoturnintoinoperablecondition.
Ifthishappens,tightentheset‑boltsothatthemainrelief
secondarypressurewillnotbereturnedtothetanktoallow
thecranetobeoperated.
Mainvalve
Pressurereducing
valve
Set‑bolt
Solenoidvalveforunloading
Reliefvalve
forstoringhook
Solenoidvalve
forstoringhook
Pressureregulatorvalve
Backpressurevalve
Tank
Solenoidvalve
forstoringhook
Primary
pressure
Secondary
pressure
Solenoidvalve
forunlading
pressurereducingvalve
Pump
Tank
2
Mainreliefvalve
2
Reliefvalveforstoringhook
2
Backpressurevalve
2
Pressureregulator
valve
2
Emergencyscrew
(Stopvalve)
3.0MPa
(30kgf/cm)
20.6MPa(210kgf/cm)
Set‑bolt
(Stopvalve)
3.9MPa(40kgf/cm)
Working
pressur
G.P
Pailotpressurer
G.P
1.0MPa
(10kgf/cm)
1.0MPa
(10kgf/cm)
Portreliefforstoringhook
Solenoidvalve
forunlading
Pressurereducingvalve
Mainreliefvalve
Backpressurevalve
3.0MPa(30kgf/cm)
2
2
1.0MPa(10kgf/cm)
Tankport
Solenoidforstoringhook
Accelerator
cylinder
Gaugeport
Gaugeportforpilotpressure
Needlevalveforreleasing
autmaticstopforover‑winding