03. Simrit - Broșura Merkel PRW 1 Double Wiper

8/12/2019 03. Simrit - Broura Merkel PRW 1 Double Wiper

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Product InformationMerkel Hydraulics

Merkel PRW 1 Double Wiperwith Integrated Pressure Relieve


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Make the most of Simrits service

package and give yourself a

real competitive edge:

Constant innovations

Uniquely wide range of

products

Strong product brands

Unique materials expertise

A wide range of value

added services

Vibration Control

Special Sealing Products: Bellows, Diaphragms,Elastomer Composite Parts and Precision Mouldings

Lederer Liquid Silicone Products

ISC O-Ring

Integral Accumulator

Merkel Hydraulics / Pneumatics

Simmerring

Simrit, Your Global Technology Specialistfor Seals and Vibration Control

This way we secure competitive

advantages for you based on

experience all around the world:

Simrit has a presence through-

out Europe, America and Asia,

either directly or through its

affiliated companies NOK

(Japan) or Freudenberg-NOK

(USA). The transfer of know-

ledge between these markets isincorporated directly into the

Simrit service package.

With our many Simrit Service

Centres and Simrit distribution

Partners, we serve and supply

more than 100,000 customers

worldwide. Our Simrit Partners

ensure rapid availability from

stock. This means spare parts

quickly arrive when and where

they are needed. There is aSimrit Partner near you as well.

Simrit, Your GlobalTechnology Specialistfor Seals and VibrationControl offers you acomplete service pack-age. A unique rangeof products and servicesguarantees you numer-ous advantages over the

competition.

Simrit acts as a partner to

general industry. Its position as

a market leader is achieved

through continuous research,

development and manufacture.

We have the worlds widest ran-

ge of seals and vibration con-

trol products, and can offer you

solutions based on the demands

of state-of-the-art-technology,solutions which set standards.

Simrit offers a complete package of

products and services, including leading

brands such as Simmerring, Merkel,

Integral Accumulator, Meillor and

ISC O-Ring.

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reliability of the sealing system

while simultaneously reducing

the total costs of the cylinder.

The use of the Merkel PRW 1

double wiper can bring about

a marked improvement in func-

tional reliability and tightness

compared with a solution in-

volving the very popular

single-action wipers.

The Merkel PRW 1 double

wiper is used by well-known

manufacturers and has already

proved its worth in a whole

range of different applications.

Pressure-relieve double wipers make hydraulic cylinderseven more reliable and economical

pressure build-up between the

seal and wiper. There is no

longer any need at all for the

pressure relieving bore pre-

viously required an economi-

cal simplification for the manu-

facture of hydraulic cylinders.

The new Merkel PRW 1 double

wiper offers greater functional

The newly developed Merkel

PRW 1 double wiper is a key

component of modern Merkel

rod seal systems in hydraulic

cylinders. This innovative step

forward with the PRW (Pressure

Relieve Wiper) involves the

patented pressure relieve

function incorporated in the

wiper. This reliably prevents


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Merkel PRW 1 double wiperwith integrated pressure relieve

Fig. 2: The patented valve function consists of three quasi-static

sealing lips, which open at approx. 3 bar, relieve the built-up

pressure in the intermediate chamber and then close again

immediately afterwards.

Today's requirementson hydraulic seals arereliability and a highlevel of tightness with asimultaneous reductionin costs. Leak-freeoperation over the entireoperating service life iscrucial, particularly in

the case of rod sealsystems. Modern rodseal systems are madeup of components thathave been speciallycoordinated to eachother.

Cost reduction thanks toMerkel PRW 1 doublewiperThe new Merkel PRW 1 double

wiper (Pressure Relieve Wiper)with an optimised sealing and

wiping effect features an inte-

grated pressure relieve func-

tion. It prevents a critical pres-

sure build-up (> 1 MPa) in the

space between the wiper and

the rod seal. The pressure

relieve function has been incor-

porated in the outer diameter.

This means there is no need for

a relieving bore between thedouble wiper and rod seal

(Pat. No: German Patent 100

10524). The dynamic sealing

lip of the Merkel PRW 1

double wiper reduces the

residual oil film of the rod seal,

avoiding undesirable wiper

leakage. The Merkel PRW 1

double wiper has been deve-

loped for housings based on

DIN/ISO 6195 type A (detai-

led information in article list onpage 7).

Fig.1: Modern rod seal system with pressure relieve Merkel PRW 1

double wiper, Merkel U-ring LF 300 and guide ring Merkel

Guivex SBK

Segmented front face provides

for pressure relieve

Static sealing lip (1)

prevents ingress of dirt

and water

Wiper lip with radius wipes

off dirt efficiently while leaving

a residual oil film on rod

Static sealing edge (2)

additional protection from

ingress of dirt and water

Segmented static

sealing lip (3)

designed for channelling

of liquid provides for

pressure relieve

Dynamic sealing lip

with knife-cut sealing edge

excellent tightness

low wear


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Drive

Oil supply Intermediate flange Dustatmosphere

Wiper underexamination

To particlesensor

Cylinder chamber

Piston rod:Piston rod :Speed:Hydraulic fluid:Pressure in cylinder:Test dust:Dust supply:

Rigid shaft Ra0.2 m50 mm0.45 m/sHLP 3250 barISO MTD of PTI5 g/h

Functional reliabilityThe attainment of the seal wear

limit and malfunctions of the

rod seal are indicated via the

wiper pressure relieve. The

system also remains functional

in this state. The Merkel PRW 1

double wiper is not pressed

out. Resulting damage to the

hydraulic system is avoided.

Ingress of dirtThe ingress of dirt via the

housing is reliably prevented

by the static sealing lip on the

front face and the static sealing

edge of the Merkel PRW 1

double wiper. The optimised

wiper lip ensures that soiling is

always removed while leaving

the lubricating film on the rod

(mean particle ingress accor-ding to ISO 4406: 1987

13/5). This means that the

Merkel PRW 1 double wiper

far exceeds the requirements

on the degree of purity as

specified by ISO 4406 for

high-performance servo systems

and high pressure systems

(Fig.3) and (Fig.4).

Contaminated oil

Light source Photocell

Measuring cell

Q = constant25 ml/min

Metering flumeMeter

P

article>x

/m

l

Particle size

Measured resultsfor a specifiedtime interval

Type of hydraulic system Degree of purity

ISO 4406: 1987

Sensitive control systems,11 / 8laboratory, aerospace industry

High-performance servo systems,14 / 11high pressure systems

High-quality and reliable systems,16 / 13gen. mechanical engineering

Medium pressure range, general18 / 14mechanical engineering and vehicles

Low pressure range, general heavy19 / 15plant engineering, vehicles

Fig.4: Functional principle of an automatic particle sensor

Fig. 5: Recommendations for degrees of purity

(source: Mahle Filterfibel)

Fig.3: Basic diagram for dirt ingress test rig


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Technical properties and behaviour

Merkel PRW 1 double wiper

made of low-temperaturepolyurethane (92 AU 21100)

for use under extremely cold

conditions on demand

Tolerance

recommendation

Nominal d D D1

16 100 H 10 H 10

Possible applications with various hydraulic media

Surface quality R max Ra

Running surface * *

Bottom of groove < 6,3 m < 1,6 m

Side of groove < 15,0 m < 3,0 m

Medium/Temperature Material 94 AU 925

Hydraulic oils, HL, HLP 30 C to + 110 C

HFA/HFB liquids + 5 C to + 50 C

HFC liquids 30 C to + 40 C

HFD liquids

Water + 5 C to + 40 C

HETG (rape seed oil) 30 C to + 60 C

HEES (synthetic ester) 30 C to + 60 C

HEPG (glycol) 30 C to + 40 C

Mineral greases 30 C to + 110 C

* The surface roughness of

the running surface should

be related to the sealing

component used!


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Merkel PRW 1 double wiperHousing based on DIN/ISO 6195 type A

Article list

d D D2 L1 L2 R(1) R(2) H3 Profile Article No.

22 30 28 4 6 0.3 0.2 7 4 49012374

25 33 31 4 6 0.3 0.2 7 4 49012375

28 36 34 4 6 0.3 0.2 7 4 528538

30 38 36 4 6 0.3 0.2 7 4 530000

32 40 38 4 6 0.3 0.2 7 4 531403

35 43 41 4 6 0.3 0.2 7 4 531022

36 44 42 4 6 0.3 0.2 7 4 531411

37 45 43 4 6 0.3 0.2 7 4 49012106

38 46 44 4 6 0.3 0.2 7 4 49005191

40 48 46 4 6 0.3 0.2 7 4 531116

45 53 51 4 6 0.3 0.2 7 4 531412

48 58 56 4 6 0.3 0.2 9 5 52667950 58 56 4 6 0.3 0.2 7 4 528607

55 63 61 4 6 0.3 0.2 7 4 528815

70 80 77 6.3 8.3 0.3 0.2 9 5 49022349

77 87 84 6.3 8.3 0.3 0.2 9 5 49005392

80 90 87 6.3 8.3 0.3 0.2 9 5 49005193

85 95 92 6.3 8.3 0.3 0.2 9 5 49005391

92 102 99 6.3 8.3 0.3 0.2 9 5 49005192

Surface correspondsto bottom of groove

rounded and burr-free


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Product InformationMerkel Hydraulics

20GB0122.0

0205Br.ABT

Simrit, Your Global Technology Specialistfor Seals and Vibration Control

Excellent tightness

Improved functional reliability

Overall reduction in costs

e. g.

Your Benefits

Simrit Services Your Benefits

Merkel PRW 1 Double Wiper with Integrated Pressure Relieve

Unique materials expertise

Vibration ControlSpecial Sealing Products: Bellows, Diaphragms,Elastomer Composite Parts and Precision Mouldings

Lederer Liquid Silicone Products

ISC O-Ring

Integral Accumulator

Merkel Hydraulics / Pneumatics

Simmerring

Headquarters EuropeFreudenberg Simrit KG

69465 Weinheim, Germany Phone: +49 (0) 1805- 74 6748Fax: +49 (0) 1803 -746748e-mail: [email protected]

Specialised technological expertise

All from one source

Technological edgeConstant innovations

Uniquely wide range of products

Strong product brands

Longer unit service life

Competitive advantages, efficiency and lower costsA wide range of value added services

03. Simrit - Broșura Merkel PRW 1 Double Wiper

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