GA

(expended) PhydrmechP

PW

M Q , p MF, v

, ,

QUALITATIVE APPROACH: FUNCTIONAL ANALYSIS

QUANTITATIVE APPROACH: NUMERICAL MODELS

GRC

WP

Q , p

Phydr

GU

WP

Date

File nametraen_eng

21 Dec 2017

ENERGY CONVERSION IN A FLUID POWER SYSTEM

PRIMEMOVER(electric motor,IC engine)

LOAD

GA: FLOW GENERATING GROUPGRC: CONTROL GROUPGU: USERS GROUP

PW

fluid leakages

mechanical friction

pressure drops

WASTED POWER(heat flow rate)

rotary shaftoil pipes oil pipes rotary shafts,

translating rods

Pmech(useful)

overall systemefficiency

Q: volumetric flow rate (L/min)p: gauge pressure (bar) - p = 0 --> atmospheric pressureM: torque (Nm) : angular speed (rad/s) / n (rev/min)F: force (N)v: linear speed (m/s)

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Date

File nameGA_GRC_GU_eng

09 Nov 2015

GA - GRC - GU

- pump(converts shaft speed into a volumetric flowrate by displacing trapped volumes of fluid)- reservoir (p = 0)- filter & heat exchanger- ...

valves:- to prevent / allow fluid flow- to direct selectively fluid- to limit / reduce a pressure- to control a flow rate (actuator speed)- ...

- linear actuators- hydraulic motors(convert volumetric flow rateinto shaft angular speed orrod linear speed)

application for printing cylinder positioning

supply line(high pressure)

return line(lowpressure)

control signal

manual electric hydraulic mechanical

directional control valve, manual operated

GA

GRC GU

pump

F, M pv,Q

motor

... and what about the fluid pressure ?

ONLY IF a flow rate meetsresistance a pressure is induced

In synthesis

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Date

File namenormintr0_eng

01 Feb 2018

YES NO

graphic representation of the model of a fluid power component or system

THE LANGUAGE OF FLUID POWER

function

operation

connections

manufacturing

dimensions

installation

GENERAL RULES: components are created using the basic symbols, taking into account the rules given for their creation symbols show the rest position of a component all ports (external connections) of a symbol must be shown basic symbols can be rotated (with increments of 90°) or mirrored to create components components must be represented in the same scale (relative size must be preserved)

International Standard ISO 1219/1-91(latest version 1219/1-2012)

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M,

A

B

P

T

GA GRC

p*

S

in regulating condition

FUNCTIONAL ANALYSIS: plant schematic according to ISO-1219

F,v

GU

Date

File namescstart_eng2

10 Feb 2018

M,

displacement

surface on which theinlet pp pressure acts

pilot line (transferspressure information)

Equations for pump and hydraulic motor (ideal)

drain line: return to thereservoir the fluid lostdue to the internalclearances

spring exerting a closingforce Fspr that can bemodified by the user

filter

unidirectional restrictor

reservoir

primemover(electricmotor)

pump

double acting linear actuator

hydraulic motor(two directions of flow)

D4/3

heat exchanger

pressure relief valve

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A

B

P

T

GRC

v

A

a

D

d F

A

B

P

T x

FUNCTIONAL ANALYSIS: plant schematic according to ISO-1219

F,v

GU

Date

File namescstart_eng3

09 Feb 2018

four-port three-positiondirection control valveclosed centre,solenoid actuated,spring centered

D = piston diameterd = rod diameter

equilibrium on the piston(steady-state)

the ingoing volume of fluid per unit time (Q)must be equal to the increment per unit timeof the chamber volume (incompressible fluid)

valid also for the outlet side:

position at rest(no command)

free flow(ideally p = p )

restricted flow(p > p )

1 2

1 2

12

restriction of the flowarea: the degree ofthrottling is decidedby the user

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Date

File namefc1a30_eng

15 Nov 2015

DUAL STAGE PRESSURE RELIEF VALVE (FLUID CONTROL 1A30)

SPOOL TYPE - CARTRIDGE CONSTRUCTION

P

T

fspr

p*S1

S2

SPOOL (MAIN STAGE) BALL POPPET (PILOT STAGE)

FUNCTIONALRESTRICTOR S1

DYNAMIC RESTRICTOR S2

INTERNAL DRAIN

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limpprop_eng

08 Jan 2018

PROPORTIONAL PRESSURE RELIEF VALVE (Denison R4VP)

P T

G

G

X Y

YX

Date

File name

mechanical pilot stage (safety)

main stage

proportional pilot stage

solenoid

LVDT

p*1

p*2

fm

S

97 Reprint 2018

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Date

File namesimVL1

08 Jan 2018

SIMULATION OF A DUAL STAGE RELIEF VALVE

S1

S2

PUMP FLOW RATE = 150 L/minD spool = 10 mmfspr = 30 Ndiameter S1 = 1 mm

S2 S1

p*

p* = 45 bar

fspr

restrictor (load)

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Date

File namesimVL2

18 Jan 2017

SIMULATION OF A DUAL STAGE RELIEF VALVE

p* main stage = 51.5 bar max pressure = 52.4 bar

p* pilot stage FORCES ON THE MAIN STAGE

p* pilot stage main stage p*

fspr / S = 3.8 bar

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Date

File namegumdevcb_eng

08 Jan 2018

RV2

VSH

p

p

GAQF (p*)

p*

1

2

2

21

A

a

VCBVCBsprF

J1J2

J3 J4

NR3NR2

J5

J7 J8

J6

J9NR1

J10

(p* )VCB

2 1

v FvF

CONTROL OF OVERRUNNING LOADS WITH "COUNTERBALANCE" VALVES

overrunning load resistant load

resistant load

overrunning load

STUDY HYPOTHESES position D2 (outward stroke) ---> flow through VCB2 resistant and overrunning loads

Remarks: leak tight conditions attained through poppet design. Spools

are not leak proof! By-pass centre of DCV to avoid spurious pilot signals RV2 is necessary to limit the pressure at the actuator outlet

2 equations to determine the pressures p1 and p2 actuator equilibrium VCB2 equilibrium

DCV

S S

sprF

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p*a

p*2

Ap* a -2p*

p*

2p*

a

v>0

v=0

v<0

p

p

1

2

p

F

2p* a

Ap*

p*A2p* A

F

Q/A

Q/a

v

2

p*VCB

Aa

Date

File namevcbpfvf_new_eng

08 Jan 2018

v FF

in

out

v

resistant load

overrunning load

DVC in D2

position D2

position D1

in

out

STEADY STATE CHARACTERISTIC p-F AND v-F WITH VCB

resistantoverrunning

resistantoverrunning

VCB open2VCB regulates2VCBclosed

2

decreasing flow area

RV

2 re

gula

tes

RV2 regulates

NR3 closed

p*VCB

Ap*VCBAp*

VCB resist.Foverr.

resistant load

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Date

File namevcb_1cpbd30

19 Jul 2017

VCB VALVE (Integrated Hydraulics 60 1CPBD300)

AB X

Y

A

B

X Y

A

B

X (cross pilot line)

ACTUATOR

DIRECTION CONTROL VALVE

integral NR valve

193 Reprint 2018

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Date

File nameguvcbsez_eng

08 Jan 2018

RV2

GAQF (p*)

p*2

21

A XY

B

PLANT WITH CONTROL OF OVERRUNNING LOAD THROUGH VCB VALVES

D0: load blockedD1: load lowering (overrunning load)D2: load lifting (resistant load)

0

B

AX

F

Note:valves representedin configuration D1

non return valve behaviourVCB behaviour

Kg

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Date

File namemodcar1_eng

24 Nov 2013

TEST RIG FOR OVERCENTRE VALVES (LOAD TEST RIG)

Primary circuit(hydraulic winch)

Secondary circuit (load)Flywheel

OVCundertest

286 Reprint 2018

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Date

File namemodcar1b_eng

24 Nov 2013

SIMPLIFIED HYDRAULIC SCHEME

br

SE

p*

D2

0

M1 M2p*

VL

LOAD TEST RIG

VL

1

Primary circuit Secondary circuit

PVB 3

s

S

p*

OVC

OVC

VPA 40 LS VPA 20 MS

NR2

01 2

1 2 P T Y

Notice that: VM1 = VM2

PVB3 is mounted on the LS test rig The flow generation unit is located downstairs Qmax PVB 3 < Q VPA 20

PVB3 decides the flow rate throughthe primary circuit

VL and NR2 decide the pressurerespectively in the high and lowpressure lines of the secondary circuit

D2 selects the type of load

287 Reprint 2018

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Date

File namemodcarico_eng

19 May 2015

P1

3A 3B

21

P2 (VPA 20)

0

GA

LS

LS test rig

T

br

SE

p*

D2

0

NR2

St

M1 M2

NR3 NR3

NR3NR3

LOAD TEST RIG

SC

1

Y1 2 P T

Q4

Q 3 Q1Q 2

SE

St

1 2

Q4NR1 NR1

Ap Bpbrakep

1p

2p

Ap Bpbrakep

brp*

M1

VPA20p

Primary circuit Secondary circuit

PVB 3

s

S

p*

OVC

OVC s

S

p*

OVC

OVC

mounting of the OVC withintegral shuttle valve

T

DETAILED SCHEME

p*VL

VL

quick couplings

288 Reprint 2018

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Date

File namemodcaricoall_eng

24 Nov 2013

COMPLETE LAYOUT

Load Sensingtest rig

Flow generating unit(downstairs)

OVC valve test rig

Data acquisition system

PVB 3 joystick

289 Reprint 2018

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