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— PRE* valves are pilot operated pressure relief valves

with electric proportional control and mounting

interface in compliance with ISO 6264 standards.

— These valves are used to control hydraulic circuit

pressure and to enable the use of the full flow rate of

the pump, even with settings approach the calibration

value.

— The two-stage design and wide passages ensure

reduced pressure drops thereby improving the system

energy performance.

— The design of these valves has a mechanical pressure

limitation feature inside the pilot stage, for higher

safety of the application.

— Valves can be controlled directly by a current control

supply unit or by means of an electronic control unit, to

exploit valve performance to the full (see par. 11).

— They are fitted with a manual pressure relief valve

which is factory set to ≥ 15% of the maximum value in

the pressure control range.

— They are available in three sizes for flow

rates up to 500 l/min and in five pressure

control ranges up to 350 bar.

PRE*

PROPORTIONAL PRESSURE

RELIEF VALVES,

PILOT OPERATED

SERIES 20

HYDRAULIC SYMBOL

OPERATING PRINCIPLE

81 311/118 ED

SUBPLATE MOUNTING

ISO 6264

p max

350 bar

Q max (see table of performances)

PERFORMANCES (obtained with mineral oil

with viscosity of 36 cSt at 50°C and electronic control card)

PRE10 PRE25 PRE32

Maximum operating pressure: bar 350

Minimum controlled pressure see ∆p-Q diagram

Maximum flow l/min 200 400 500

Step response see paragraph 6

Hysteresis (PWM 200 Hz) % of p nom < 5%

Repeatability % of p nom < ±1,5%

Electrical characteristic see paragraph 5

Ambient temperature range °C -20 / +60

Fluid temperature range °C -20 / +80

Fluid viscosity range cSt 10 ÷ 400

Fluid contamination degree

According to ISO 4406:1999

class 18/16/13

Recommended viscosity cSt 25

Mass: kg 5 5,8 8

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PRE*

SERIES 20

- IDENTIFICATION CODE

Coil electrical connection:

plug for connector type

EN 175301-803

(ex DIN 43650) (standard)

Seals:

N = NBR seals for mineral oil (standard)

V = FPM seals for special fluids

Series No.

(from 20 to 29 sizes and mounting dimensions

remain unchanged)

Size: 10 = ISO 6264-06

25 = ISO 6264-08

32 = ISO 6264-10

Pressure control range:

025 = up to 25 bar

070 = up to 70 bar

140 = up to 140 bar

210 = up to 210 bar

350 = up to 350 bar

D12 = Nominal solenoid voltage 12V DC

D24 = Nominal solenoid voltage 24V DC

Pilot operated pressure

relief valve

Electric proportional control

2 - CHARACTERISTIC CURVES

(

measured with viscosity of 36 cSt at 50°C)

Typical control curves according to the current supplied to the solenoid (D24 version with maximum current 860 mA) for the available pressure

control ranges, measured with input flow rate Q = 50 l/min. Curves have been obtained without any hysteresis and linearity compensation and

they have been measured without any backpressure in T.

MINIMUM CONTROLLED PRESSURE pmin = f (Q)

PRESSURE VARIATION pmax = f (Q))

P R E - / 20 - K1

PRESSURE CONTROL p = f (I)

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PRE*

SERIES 20

7 - INSTALLATION

We recommend installing the PRE* valve either in horizontal

position, or vertical position with the solenoid downward. If the valve

is installed in vertical position and with the solenoid upward, you

must consider possible variations of the minimum controlled

pressure, if compared to what is indicated in paragraph 2.

Ensure there is no air in the hydraulic circuit. In particular

applications, it can be necessary to vent the air entrapped inside

the solenoid tube, by using the apposite drain screw (see par. 8 - 9

- 10). At the end of the operation, make sure of having correctly

screwed the drain screw.

Connect the T port on the valve directly to the tank. Add any

backpressure value detected in the T line to the controlled pressure

value.

Maximum admissible backpressure in the T line, under

operational conditions, is 2 bar.

Valves are fixed by means of screws or tie rods on a flat surface

with planarity and roughness equal to or better than those indicated

in the relative symbols. If minimum values are not observed, fluid

can easily leak between the valve and support surface.

Surface finishing

5 - ELECTRICAL CHARACTERISTICS

Proportional solenoid

The proportional solenoid comprises two parts: tube and coil.

The tube, screwed to the valve body, contains the armature which is

designed to maintain friction to a minimum thereby reducing

hysteresis.

The coil is mounted on the tube secured by means of a lock nut and

can be rotated through 360° depending on installation clearances.

6 - STEP RESPONSE

(obtained with mineral oil with viscosity of 36 cSt at 50°C and electronic

control card)

Step response is the time taken for the valve to reach 90% of the

set pressure value following a step change of reference signal.

The table illustrates typical step response times measured with a

PRE32-210 and with input flow rate Q = 50 l/min, and a pressure oil

volume of 2 litres. The response time is affected by both the flow

rate and the oil volume inside the piping.

REFERENCE SIGNAL STEP 0 → 100% 100 → 0%

Step response [ms] 120 90

NOMINAL VOLTAGE

V DC

12 24

RESISTANCE (at 20°C)

Ω 3.66 17.6

NOMINAL CURRENT

A 1.88 0.86

DUTY CYCLE

100%

ELECTROMAGNETIC

COMPATIBILITY (EMC)

According to

2014/30/EU

CLASSOFPROTECTION

atmospheric agents (IEC 60529)

coil insulation (VDE 0580)

impregnation

IP 65

class H

class F

- MAX PRESSURE VALUES

This valve incorporates a mechanical limit of the maximum pressure, that operates independently of the applied current. This kind of design

ensures the pressure cannot rise over even if the solenoid current exceeds the maximum current (I > I

Values obtained with oil viscosity of 36 cSt at 50°C, Q = 50 l/min

4 - HYDRAULIC FLUIDS

Use mineral oil-based hydraulic fluids HL or HM type, according to ISO 6743-4. For these fluids, use NBR seals (code N). For fluids HFDR type

(phosphate esters) use FPM seals (code V). For the use of other kinds of fluid such as HFA, HFB, HFC, please consult our technical

department.

Using fluids at temperatures higher than 80 °C causes a faster degradation of the fluid and of the seals characteristics. The fluid must be

preserved in its physical and chemical characteristics.

PRE*-025 PRE*-070 PRE*-140 PRE*-210 PRE*-350

pressure value at 800 mA (bar) 27 85 147 220 365

max pressure value when I > I

max

(bar) 35 95 165 255 370

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PRE*

SERIES 20

- PRE10 OVERALL AND MOUNTING DIMENSIONS

dimensions in mm

MOUNTING INTERFACE:

ISO 6264-06-09-*-97

(CETOP 4.4.2-2-R06-350)

Fastening bolts: 4 SHCS M12x40 - ISO 4762

Torque: 69 Nm (A8.8 screws)

Thread of mounting holes: M12x20

Mounting surface with sealing rings:

2 OR type 123 (17.86x2.62) - 90 Shore

1 OR type 109 (9.13x2.62) - 90 Shore

EN 175301-803 (ex DIN 43650) electric connector

Connector removal space

Coil removal space

Breather (male hexagonal spanner 4)

Pressure relief valve (factory set)

NOTE:

at the first start up, or after a long period of no use,

it is necessary to vent the air through the breather

(5) placed at the end of the solenoid tube.

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SERIES 20

- PRE25 OVERALL AND MOUNTING DIMENSIONS

dimensions in mm

Mounting surface with sealing rings:

2 OR type 3118 (29.82x2.62) - 90 Shore

1 OR type 109 (9.13x2.62) - 90 Shore

EN 175301-803 (ex DIN 43650) electric connector

Connector removal space

Coil removal space

Breather (male hexagonal spanner 4)

Pressure relief valve (factory set)

NOTE:

at the first start up, or after a long period of no use,

it is necessary to vent the air through the breather

(5) placed at the end of the solenoid tube.

MOUNTING INTERFACE:

ISO 6264-08-13-*-97

(CETOP 4.4.2-2-R08-350)

Fastening bolts: 4 SHCS M16x60 - ISO 4762

Torque: 170 Nm (A8.8 screws)

Thread of mounting holes: M16x25

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PRE*

SERIES 20

0 - PRE32 OVERALL AND MOUNTING DIMENSIONS

dimensions in mm

MOUNTING INTERFACE

ISO 6264-10-17-*-97

(CETOP 4.4.2-2-R10-350)

Fastening bolts: 4 SHCS M18x60 - ISO 4762

Torque: 235 Nm (A8.8 screws)

Thread of mounting holes: M18x27

NOTE:

at the first start up, or after a long period of no use,

it is necessary to vent the air through the breather

(5) placed at the end of the solenoid tube.

Mounting surface with sealing rings:

2 OR type 4137 (34.52x3.53) - 90 Shore

1 OR type 109 (9.13x2.62) - 90 Shore)

EN 175301-803 (ex DIN 43650) electric connector

Connector removal space

Coil removal space

Breather (male hexagonal spanner 4)

Pressure relief valve (factory set)

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PRE*

SERIES 20

PRE10 PRE25 PRE32

Type

PMRQ3-AI4G

rear ports

PMRQ5-AI5G

rear ports

PMRQ7-AI7G

rear ports

P, T ports dimensions

P: 1/2” BSP

T: 3/4” BSP

1” BSP 1” ¼ BSP

X port dimensions 1/4” BSP 1/4” BSP 1/4” BSP

1 - ELECTRONIC CONTROL UNITS

EDC-112

for solenoid 24V DC

plug version

see cat.

89 120

EDC-142

for solenoid 12V DC

EDM-M112

for solenoid 24V DC

DIN EN 50022

rail mounting

see cat.

89 251

EDM-M142

for solenoid 12V DC

12 - SUBPLATES

(

see catalogue 51 000)

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SERIES 20

REPRODUCTION IS FORBIDDEN. THE COMPANY RESERVES THE RIGHT TO APPLY ANY MODIFICATIONS.