perbandingan acrylic, kaca dengan polycarbonat, keuntungan dan kerugian serta aplikasinya
kumpulan bahan
OBDeleven PRO vs VCDS ( VAG COM ) vs VCP ( Vag Can Pro) vs Carista vs Carly for VAG vs Launch EasyDiag supported functions CompareFull description
Sandingan Sistem Manajemen Keamanan Informasi vs Sistem Manajemen Anti Penyuapan vs Sistem Manajemen Mutu vs Sistem Manajemen LayananFull description
PEOPLE VS PASUDAG, PEOPLE VS ZUELA, PEOPLE VS ABE VALDEZ PEOPLE VS PASUDAG, PEOPLE VS ZUELA, PEOPLE VS ABE VALDEZ CasesFull description
digestedFull description
Comparison of Petrol diesel,lpg & CNG run vehicle cars
VS Aristóteles - EnsayosDescripción completa
Descripción: P
difference between guilty and plead guilty under indian evidence act and inherent powers of the high courtFull description
vdb
cabague
kk
Full description
LSDeskripsi lengkap
Descripción: texto
Proportional, Priority, Pressure Compensated Hydraulic Systems Objectives: • Provide students with a comparison of a basic PPPC hydraulic system to a basic LS/PC hydraulic system • Explain PPPC hydraulics as it is used on representative Cat products
FLOW CONTROL VALVE PRESSURE REDUCING VALVE ORIFICE
FLOW CONTROL VALVE PRESSURE REDUCING VALVE ORIFICE
Definition: Pressure Compensation A control system which results in constant implement speed for a given lever displacement. The system does this by maintaining a controlled pressure drop across the main control or directional spool in each circuit.
LOAD SENSING WITH SIGNAL NETWORK
ENGINE
RESOLVER
LOAD
300 PSI SPRING RESOLVER LOAD FLOW CONTROL VALVE RESOLVER 3000 PSI SPRING
A RELIEF VALVE
B
SIGNAL NETWORK
BOOM
ENGINE
SWING
LEFT RIGHT STABILIZER STABILIZER
BUCKET
STICK PRIMARY RESOLVER SECONDARY RESOLVER
300 PSI SPRING
FLOW CONTROL VALVE
3000 PSI SPRING
RELIEF VALVE
TO IMPLEMENT CONTROL VALVES
Definition: Load Sensing A control system that maintains a pump supply pressure at a fixed value above the highest system pressure requirement.
VARIABLE DISPLACEMENT PUMP PUMP OUTPUT LARGE ACTUATOR
YOKE PAD SWASH PLATE
DRIVE SHAFT
FLOW COMPENSATOR ( MARGIN SPOOL)
PRESSURE COMPENSATOR (PRESSURE CUT-OFF)
SMALL ACTUATOR & BIAS SPRING
LOAD SENSING / PRESSURE COMPENSATION
LOAD ENGINE
FIXED DISPLACEMENT PUMP DOUBLE CHECK VALVE
300 PSI SPRING
FLOW CONTROL VALVE
3000 PSI SPRING
50 PSI SPRING
PRESSURE REDUCING VALVE
CLOSED CENTER CONTROL VALVE
LOAD SENSING / PRESSURE COMPENSATION PUMP CONTROL VALVE
LOAD
ENGINE
VARIABLE DISPLACEMENT PUMP
DOUBLE CHECK VALVE
50 PSI SPRING
PRESSURE REDUCING VALVE
CLOSED CENTER CONTROL VALVE
LOAD SENSING TWO VALVE OPERATION MOTOR
LOAD
LOAD 300 PSI SPRING
3000 PSI SPRING
A
B
LS Only - Pressure Differentials Flow Needs Met Maximum Pump Flow = 30 gpm Valve A desired flow = 10 gpm Valve B desired flow = 10 gpm Margin Pressure is normal System Pressure = Valve A load plus margin pressure = 2300 psi
If Valve A load stayed the same and Valve B would vary as the load on the circuit varied, the operator would have to constantly shift the lever to maintain implement control.
LOAD SENSING / PRESSURE COMPENSATION TWO VALVE OPERATION ENGINE LOAD
300 PSI SPRING
LOAD 50 PSI SPRING
3000 PSI SPRING
A
50 PSI SPRING
B
LS/PC - Pressure Differentials Flow Needs Met Maximum Pump Flow = 30 gpm Valve A desired flow = 10 gpm Valve B desired flow = 10 gpm Margin Pressure is normal System Pressure = Valve A load plus margin pressure = 2300 psi
LS/PC - When Flow Demand Exceeds Available Pump Flow Maximum Pump Flow = 30 gpm Margin Pressure less than normal
Valve A @ 2000 psi Valve B @ 1000 psi Valve C @ 500 psi Total
Desired Flow 30 gpm 20 gpm 10 gpm
Available Flow 0 gpm 20 gpm 10 gpm
60 gpm
30 gpm
PPPC HYDRAULIC SYSTEM TWO VALVE OPERATION / FLOW NEEDS MET 2000 PSI
1000 PSI 10 GPM FLOW REQ'D
10 GPM FLOW REQ'D
VALVE B
VALVE A
PRESSURE COMPENSATING CHECK VALVE
FEEDER PASSAGE
BRIDGE PASSAGE
50 PSI SPRING
PILOT OIL
DIRECTIONAL SPOOL
PILOT OIL SIGNAL LIMITER VALVE
300 PSI MARGIN SPRING PUMP 3500 PSI CUTOFF SPRING
50 PSI SPRING
30 GPM MAXIMUM FLOW
3000 PSI SPRING
PPPC - Pressure Differentials Flow Needs Met Maximum Pump Flow = 30 gpm Valve A desired flow = 10 gpm Valve B desired flow = 10 gpm Margin Pressure is normal System Pressure = Valve A load plus margin pressure = 2300 psi
PPPC - When Flow Demand Exceeds Available Pump Flow Maximum Pump Flow = 30 gpm Margin pressure less than normal
Valve A @ 2000 psi Valve B @ 1000 psi Valve C @ 500 psi Total
Desired Flow 30 gpm 20 gpm 10 gpm
Available Flow 15 gpm 10 gpm 5 gpm
60 gpm
30 gpm
Definition: Proportional, Priority, Pressure Compensated Hydraulic System Provides precise multiple circuit flow control whenever pump flow is exceeded. This is accomplished through post main spool pressure compensation, which results in proportional flow division.
PPPC HYDRAULIC SYSTEM TWO VALVE OPERATION / CUTOFF CONTROLS MAX. PRESSURE 3500 PSI
1000 PSI 10 GPM FLOW REQ'D
VALVE B
VALVE A
PRESSURE COMPENSATING CHECK VALVE
FEEDER PASSAGE
BRIDGE PASSAGE
50 PSI SPRING
PILOT OIL
DIRECTIONAL SPOOL
PILOT OIL SIGNAL LIMITER VALVE
300 PSI MARGIN SPRING PUMP 3500 PSI CUTOFF SPRING
50 PSI SPRING
30 GPM MAXIMUM FLOW
4000 PSI SPRING
PPPC - Pressure Differentials Pressure Cutoff Controls Maximum System Pressure Maximum Pump Flow = 30 gpm Valve A desired flow = Stalled Valve B desired flow = 10 gpm Actual Flow = 0 gpm Margin pressure = 0 System Pressure = Controlled by Pressure Cutoff = 3500 psi