Pressure-reducing valve, pilot-controlled type VDM

Product documentation

pilot-controlled
Operating pressure pmax: 400 bar
Flow rate Qmax: 120 lpm

D 5579
09-2018-1.1
© by HAWE Hydraulik SE.
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Printing date / document generated on: 25.09.2018

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 Contents

1 Overview: Pressure reducing valve type VDM and VDX........................................................................................... 4

2 Available versions, main data............................................................................................................................. 5

3 Parameters......................................................................................................................................................... 7

4 Dimensions...................................................................................................................................................... 10
4.1 Pipe connection................................................................................................................................................. 10
4.2 Manifold mounting............................................................................................................................................. 11

5 Assembly, operation and maintenance recommendations.....................................................................................12

5.1 Intended use..................................................................................................................................................... 12
5.2 Assembly information......................................................................................................................................... 12
5.2.1 Creating the mounting hole................................................................................................................................. 12
5.3 Operating instructions.........................................................................................................................................13
5.4 Maintenance information..................................................................................................................................... 13

6 Other information.............................................................................................................................................14
6.1 Functional description........................................................................................................................................ 14

© HAWE Hydraulik SE D 5579 - 09-2018-1.1 3/15

 1 Overview: Pressure reducing valve type VDM and VDX

Pressure reducing valves are a type of pressure control valve. They maintain a
largely constant outlet pressure even at a variable (higher) inlet pressure.
The pressure reducing valve type VDM is hydraulically pilot-controlled. These
valves feature an override compensation, i.e. acting like a pressure-limiting valve
if the secondary pressure exceeds the set pressure e.g. due to external forces.
There is a design-related leakage ow.
Pressure reducing valve type VDM
Features and benets:
■ With safety valve function
■ Various adjustment options
■ Various additional functions

Intended applications:
■ General hydraulics
■ Jigs
■ Test benches

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 2 Available versions, main data

Circuit symbol: VDM VDX

Order coding example:

VDM 3 G H R - 250

Pressure specification (bar) for max. outlet pressure

Adjustment Table 5 Adjustment

Pressure range Table 4 Pressure range

Line connection Table 3 Line connection

Size Table 2 Size

Basic type Table 1 Basic type

Table 1 Basic type

Basic type Description

VDM hydraulically pilot-controlled pressure reducing valve
VDX hydraulically remote-controlled pressure reducing valve
Pilot valve PG 1.. according to D 4350 to L line and then unpressurised to the tank

Table 2 Size

Coding Flow rate

Qmax (lpm)
3 40
4 80
5 120

Table 3 Line connection

Coding Description Size

3 4 5
G Pipe connection G 1/2 (BSPP) G 3/4 (BSPP) G 1 (BSPP)
P Manifold mounting -- #13 #17

© HAWE Hydraulik SE D 5579 - 09-2018-1.1 5/15

Table 4 Pressure range

Coding Adjustment area for outlet pressure max. inlet pressure max. pressure difference between
(bar) (bar) inlet pressure and outlet pressure
(bar)
N 8 ... 100 400 300
H 10 ... 400 400 300

Note
Always monitor the pressure gauge when setting or changing the pressure yourself!

Table 5 Adjustment

Coding Description
No designation Series, xed (tool adjustable)
R Manually adjustable

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 3 Parameters

General information

Designation pressure reducing valve, pilot-controlled

Design spool valve

Model manifold mounting, pipe connection

Ports P - pressure oil input (pump)

A - reduced pressure
L = drain port (unpressurised to the tank)

Material Steel; nitrided valve housing, hardened and ground functional inner parts

Installation position As desired

Flow direction Work ow direction always P d A, in opposite direction free back pressure possible (see Sp-
Q characteristics), P = supply ow (primary side), A = consumer (secondary side)

Leakage oil (control oil drain) • with all valves independently of the pressure setting approx. 0.40 lpm
• escaping at L, unpressurised to the tank

Hydraulic uid Hydraulic oil: as per Part 1 to 3; ISO VG 10 to 68 according to DIN 51 519
Viscosity range: min. approx. 4 mm2/s
Optimal operating range: max. approx. 1500 mm2/s
Also suitable for biologically degradable pressure uids type HEPG (polyalkylene glycol) and
HEES (synthetic ester) at operating temperatures up to approx. +70°C.

Cleanliness level ISO 4406

21/18/15...19/17/13

Temperatures Ambient: approx. -40 ... +80°C, Fluid: -25 ... +80°C, Note the viscosity range!
Permissible temperature during start: -40°C (observe start-viscosity!), as long as the service
temperature is at least 20K higher for the following operation.
Biologically degradable pressure uids: Observe manufacturer's specifications. By considera-
tion of the compatibility with seal material not over +70°C.

© HAWE Hydraulik SE D 5579 - 09-2018-1.1 7/15

Characteristics

Oil viscosity approx. 32 mm2/s Δp-Q characteristics

A ow in the opposite direction A d P is only possible with the pilot valve closed, i.e. below
the outlet pressure set (control piston in open home position). The return ow should not
be greater than approx. 50% of Qmax here. If reversal of the ow direction is to be expected
during the control process (control piston in throttle position), the control piston would then
block the return ow. In such cases or when the full return ow must be possible in control
terms, a bypass check valve is required.

Q ow rate (lpm); Sp ow resistance (bar)

1 Size 4
2 Size 5
3 Size 3

Δp-QA characteristics

1 Pressure setting
2 Pressure drop approx. 5%

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Weight

Type
VDM 3 G, VDX 3 G = 1.1 kg
VDM 4 G, VDX 4 G = 1.5 kg
VDM 5 G, VDX 5 G = 2.0 kg
VDM 4 P, VDX 4 P = 2.0 kg
VDM 5 P, VDX 5 P = 2.5 kg

© HAWE Hydraulik SE D 5579 - 09-2018-1.1 9/15

 4 Dimensions

All dimensions in mm, subject to change.

4.1 Pipe connection

VDM 3 G, VDM 4 G VDM 5 G

VDX 3 G, VDX 4 G VDX 5 G

1 Pilot valves see below

Type a b c d e f g h i k l
VDM 3 G 60 65 30 25 34 27 11 51.5 7.5 8.5 56.5
VDM 4 G 65 71 40 26.5 39 25 15 55 10 7 60

Size Ports (ISO 228-1) (BSPP)

P, A L
3 G 1/2
4 G 3/4 G 1/4
5 G1

Pilot valves

VDM VDX
Fixed Coding R

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4.2 Manifold mounting

VDM 4 P VDM 5 P
VDX 4 P VDX 5 P

1 Pilot valves see Chapter 4.1, "Pipe connection"

Base plate hole pattern

VDM 4 P VDM 5 P
VDX 4 P VDX 5 P

© HAWE Hydraulik SE D 5579 - 09-2018-1.1 11/15

 5 Assembly, operation and maintenance recommendations

5.1 Intended use

This valve is intended exclusively for hydraulic applications (uid technology).

The user must observe the safety measures and warnings in this documentation.

Essential requirements for the product to function correctly and safely:

– All information in this documentation must be observed. This applies in particular to all safety measures and warnings.
– The product must only be assembled and put into operation by qualied personnel.
– The product must only be operated within the specied technical parameters. The technical parameters are described in detail in this
documentation.
– The operating and maintenance manual of the components, assemblies and the specic complete system must also always be
observed.

If the product can no longer be operated safely:

1. Remove the product from operation and mark it accordingly.
✓ It is then not permitted to continue using or operating the product.

5.2 Assembly information

Danger
Risk to life caused by sudden movement of the hydraulic drives when dismantled incorrectly!
Risk of serious injury or death.
■ Depressurise the hydraulic system.
■ Perform safety measures in preparation for maintenance.

5.2.1 Creating the mounting hole

See description in Chapter 4, "Dimensions".

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5.3 Operating instructions

Note product configuration and pressure / ow rate

The statements and technical parameters in this documentation must be strictly observed.
The instructions for the complete technical system must also always be followed.

Note
■ Read the documentation carefully before usage.
■ The documentation must be accessible to the operating and maintenance staff at all times.
■ Keep documentation up to date after every addition or update.

Caution
Risk of injury on overloading components due to incorrect pressure settings!
Risk of minor injury.
■ Always monitor the pressure gauge when setting and changing the pressure.

Purity and ltering of the hydraulic uid

Fine contamination can significantly impair the function of the hydraulic component. Contamination can cause irreparable damage.

Examples of ne contamination include:

– Metal chips
– Rubber particles from hoses and seals
– Dirt due to assembly and maintenance
– Mechanical debris
– Chemical ageing of the hydraulic uid

Note
Fresh hydraulic uid from the drum does not always have the highest degree of purity. Under some circumstances the fresh
hydraulic uid must be ltered before use.

Adhere to the cleanliness level of the hydraulic uid in order to maintain faultless operation.
(also see cleanliness level in Chapter 3, "Parameters").

Additionally applicable document: D 5488/1 Oil recommendations

5.4 Maintenance information

Conduct a visual inspection at regular intervals, but at least once per year, to check if the hydraulic connections are damaged. If
external leakages are found, shut down and repair the system.
Clean the device surface of dust deposits and dirt at regular intervals, but at least once per year.

© HAWE Hydraulik SE D 5579 - 09-2018-1.1 13/15

 6 Other information

6.1 Functional description

Function
The pressure reducing valve type VDM and VDX is hydraulically pilot-controlled. It consists of a main valve and a pilot valve.
The required outlet pressure is set with the pilot valve (ange-mounted pressure-limiting valve).
In the main valve a spring-loaded piston (pressure maintenance valve) is controlled via the pilot valve. The piston continuously changes
a ow cross section as a function of the inlet pressure. If the inlet pressure increases, the throttle resistance increases by the same
amount. If the inlet pressure drops, the throttle resistance falls by the same amount. This maintains the outlet pressure (= difference
between inlet pressure and throttle resistance) at a constant level.
The control oil ow, which is necessary for the control action of the piston, is drained externally via the pilot valve as leakage ow.

Schematic diagram

1 Input
2 Output
3 Leakage oil
4 Main valve
5 Pilot valve
6 Sealing disc

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 Further information

Additional versions
■ Pressure-limiting valve type DV, DVE and DF: D 4350
■ Pressure-reducing valve type ADM: D 7120
■ Pressure-reducing valve type CDK: D 7745
■ Proportional pressure-reducing valve type PDM and PDMP: D 7584/1
■ Proportional pressure-limiting valve type PDV and PDM: D 7486
D 5579 - 09-2018-1.1

HAWE Hydraulik SE
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Tel +49 89 379100-1000 | Fax +49 89 379100-91000 | info@hawe.de | www.hawe.com