Technical Manual 2011

TECHNICAL MANUAL

INDEX

INTRODUCTION

• Introduction • Warning on safety

BASICS OF HYDRAULICS

• Hydraulic systems and fluids • Basics of hoses and assemblies • Hoses description

• High pressure hydraulics: main applications

HOSE SELECTION

• Introduction

• Rubber hose structure

• Hydraulic hose international standards • Hose selection criteria

• Storage and shelf life conditions • Manuli recommendations • Service life considerations • Hose assembly routing

COUPLING SELECTION

• Introduction

• How to identify fluid connections • End-thread measurement • Couplings selection criteria

• MF2000 Manuli part numbering system • MF3000 Manuli part numbering system • MF4000 Manuli part numbering system • Termination ends and torque values • SAE Standard connections

• Metric couplings

• BSP (British Standard Pipe) • Japanese Style fittings - JIS B 8363 • NF French Standard connections • OEM Special connections • Torque values details • O-Ring recommendations • Adaptors

• Port dimensions

MINING

• Introduction

• Mining product range • MDG41 Compliance

• MF2000 Manuli partnumbering system • MF3000 Manuli partnumbering system • MF4000 Manuli partnumbering system • Mining adaptors part numbering system • Mining staples part numbering system • Mining ball valves part numbering system

QUICK COUPLINGS

• Introduction • QSafe applications

• Structure of a quick-coupling • QSafe product range • QSafe part numbering system

REFRIGERATION

• Refrigeration applications • Hoses and fittings

• Refrigerants and lubricants • Specifications

HOSE ASSEMBLY

• Hose assembly data • Cleaning, inspection, testing • Hose assembly installation tips • Hose protection

• European legislation on safety and conclusion

MAINTENANCE

• Maintenance • Periodic inspections

• Hose assembly troubleshooting guide

APPENDIX

• System of units and conversion • Glossary • Type approvals 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 3 4 6 9 10 14 14 17 19 20 20 22 24 39 41 43 47 49 50 53 55 56 60 62 64 66 66 71 74 76 77 78 79 82 84 85 91 92 92 96 97 98 98 98 101 101 103 104 104 105 108 113 117 118 120 123 123 125 126 128 129 131 134 135 136 137 140 147 148 152 165

www.manuli-hydraulics.com

[email protected]

INTRODUCTION

The purpose of this booklet is to provide technical information to support customers, OEMs and users for a proper selection, installation and use of the Manuli products.

Manuli offers an integrated hydraulic product range of fluid connectors, hose assemblies, hydraulic hoses, couplings, adaptors, accessories and crimping machines.

Catalogue describes the complete product range, while the present technical manual has the target to advise you how to proper install and maintain hydraulic products.

All Manuli hydraulic products will provide you with a long ser-vice life if they are properly selected, installed and maintained; the best way to achieve this, is a preliminary deep study of the application in order to select the proper components considering the mission profile and a preventive mainte-nance programme.

Your system/equipment applications study will drive you in the correct choice of the right Manuli components to achieve reliable solutions, ergonomics and suitable hose configura-tions, etc. This booklet suggests how to study the applicaconfigura-tions, evaluating their severity and technical aspects, in order to avoid potential mistakes since the preliminary design activities of the system/equipment.

Preventive maintenance is especially important, in fact the high pressures and temperatures which characterise hydraulic applications make hose and fitting selection, installation and maintenance critical. If done incorrectly, the risk of injury and/or excessive and costly downtime increases. That’s why there are several good reasons to implement a preventive maintenance programme:

• improving workers safety; • avoiding production downtime; • reducing repairs costs, etc.

A preventive maintenance programme will enhance also the productivity because your equipment will be in good operat-ing condition at any times, minimisoperat-ing safety hazards.

Combining the proper Manuli high quality products with a regular preventive maintenance programme, will keep your hoses and fittings trouble-free for a long time. An effective pre-ventive maintenance programme can be summarised in the following key elements:

• proper hose and fitting selection, evaluating the application type;

• proper assembly installation;

• maintaining a safe work environment;

Information contained in this document is intended for guidance only and may be subject to change. Any change will be notified (at the discretion of Manuli Rubber Industries) via selected communi-cation channels.

Remark

• regularly scheduled inspections;

• troubleshooting (identifying problems and solutions); • well-trained personnel.

Additional technical information on components and acces-sories, are supplied in order to support the assemblers and users: O-Rings dimensions, torque for coupling installation, routing tips, appendix with measurement units conversion, etc.

The information and details provided in this manual are also available through dedicated training courses. In addition, Manuli application engineers are always available to assist assemblers and OEMs on product applications. In case of need, please contact your closest Manuli representative.

5

WARNING ON SAFETY

Never underestimate the power of a blown hydraulic assembly. Serious injury, death and destruction of property can result from rupture or blow-off of a hydraulic hose assembly.

Hoses:

• damaged or worn out

• incorrectly assembled or installed

• not properly selected for the intended use/application are serious hazards.

Be aware of the dangers connected with hydraulic pres-surised systems/components

Hydraulic fluid under pressure is dangerous and can cause serious injury. Here are listed few common problems that may arise during the use of hydraulic hose assemblies and systems under pressure:

Pinhole

Hydraulic fluid, when released as a fine stream through a pin-hole in the hose, can easily penetrate the skin. If this happens, seek medical assistance immediately. Fluid injections are con-sidered a serious injury requiring prompt medical attention. Leak

Leaking hydraulic fluid is hazardous. In addition to making workplace floors slippery and dangerous, leaks also contami-nate the environment. Before cleaning an oil spill, always check local regulations.

Burst

Whether due to improper selection or damage, a ruptured hose can cause injury. If it bursts, people can be burned, cut, injected or injured because of equipment malfunction. Coupling blow-off

If the assembly is not properly made or installed, the coupling could come off with subsequent risk for severe personal injury. Whipping hose

If pressurised hose ends or end fittings come apart, the loose hose ends can flail or whip with great force and fittings can be thrown off at high speed.

Stored energy

Hydraulic systems sometimes use accumulators to store poten-tial energy or absorb shock. This energy can create pressure that keeps the system’s components moving. Charged accu-mulators can be lethal. Always open the accumulator’s valve to release pressure. Stay out of hazardous areas while testing hoses under pressure. Use proper safety protection.

7 Due to the serious criticalities of hydraulic applications it is

impor-tant to select and install assemblies with proper criteria: • select proper hose assemblies for the application, considering

the numerous factors and conditions affecting the function-ality and technical ability of the hose to meet the require-ments;

• hose assembly routing must not create an injury hazard or damage to the hose;

• select hydraulic components so that the application's tem-perature, pressure (including the possible peaks) and bend radius do not exceed recommended component limits; • never mix products from different manufacturers: evaluation

of hose and couplings combination requires relevant qualifi-cation programs, including in particular impulse testing and cannot be determined by a simple burst or proof pressure test. Manuli disclaims all liability for any hose assembly made in violation of Manuli recommendations, procedures and current swaging data (the swaging chart is updated every year);

• hoses must not be stretched, kinked, crushed or twisted during installation or use;

• hoses must not be bent to less than the minimum bend radius;

• do not use hydraulic hose to convey high pressure gases unless specifically designed and qualified for these applica-tions;

Follow good maintenance practices

• establish a program of inspection and eventual replacement of hose assemblies, considering factors including:

- severity of application

- frequency of equipment use (mission profile)

- past performance of hose assemblies on the same equip-ment (historical data)

• record maintenance data regarding inspections and testing or substitution of assemblies, etc.

• only properly trained personnel should inspect, test or serv-ice hose assemblies.

Avoid injury for operating personnel and users/others • fluid under pressure can cause serious injury. It can be

almost invisible escaping from a pinhole, and it can pierce into the body;

• do not touch a pressurised hydraulic hose assembly with any part of your body;

• if fluid punctures the skin, even if no pain is felt, a serious emergency exists and a medical assistance is necessary immediately. Missing assistance can result in loss of the injured body part or death;

• stay out of hazardous areas when testing hose assemblies under pressure. Use proper safety protection;

• operating personnel must receive training on the use of hoses, couplings and assembly equipment, hose installation practices following the current operating manuals and swaging data;

• use only new (unused) recommended hose and fittings with the recommended swaging machines and correct crimp information; ensure that your assembly equipment is properly maintained and calibrated;

• operating personnel must wear safety glasses and proper protective clothes;

• if there are risks impacting safety requirements install proper protective shields and/or restraint systems (whipcheck) to protect the personnel from potential failures of the pres-surised hydraulic components;

• be aware that some hydraulic fluids are highly flammable.

Refer to SAE J1273 par. 4 specification for further details on safety aspects.

8

J1273

for Hydraulic Hose Assemblies

HYDRAULIC SYSTEMS AND FLUIDS

Energy transmission systems Motors supply mechanical energy.

An electric motor gets its motion from an electric flow of ener-gy, transforming it in mechanical power: supplying another form of energy to be used otherwise. Also chemical energy is transformed: a good example are diesel or petrol engines whose movement supply energy.

Unfortunately this first transformation is often unsatisfactory for the actual needs of many applications.

Not always the place where the action is required can be equipped with a motor and a proper operator.

The solution to this problem can be found making energy flow from the prime mover to the application point.

A common way to do this is by the use of hydraulic systems. Any mass can have potential and kinetic energy; a fluid can also "transport" it from one point to another.

For example, waterfalls take advantage of the potential ener-gy linked to the different heights at which the water is before and after the transmission.

Some turbines get their motion from the kinetic energy of the used fluid.

Other systems (the ones we will deal with in this manual) use an energy flow under form of pressure.

Hydraulic circuits

A hydraulic circuit is a system to supply energy, transported by means of a fluid under pressure.

A prime mover drives generally a pump whose task is to send a fluid into a circuit: it converts the mechanical energy of the motor into fluid power.

The fluid moves along a pipeline and reaches an actuator: generally a cylinder but often also a hydraulic motor (rotary actuator).

The described circuits can be represented by simple schemes related to a system with a linear actuator (cylinder), similarly in the case of rotative actuators (hydraulic motors).

The pipeline

The pipeline conveys the fluid; it may be built either with rigid steel pipes or with flexible hoses or also using a combined solution.

Many applications would hardly accept a rigid pipeline; often the connected parts are in relative motion between them-selves and a flexible hose suits at best the needs.

Moreover, using fluid transmission mainly in engines operating 10

fig. 1 - Hydraulic circuit with cylinder

fig. 2 - Basic hydraulic circuit

fig. 3 - Hydraulic cylinders

Actuator Load Load Cylinders discharge lines potential criticalities for hose assemblies: negative load surges

Pump outlets potential criticali-ties for hose assemblies: - pressure surges - vibration - temperature - severe installations Pump Motor Tank

at high speed, the systems have also a lot of vibrations; a flexible part in the system can better absorb them so to create a sort of insulation.

Flexible hoses will be widely described in this manual; basically the hose consists in a rubber tube winded up by a reinforcement and covered with a rubber or textile layer. The reinforcement consists in steel wires or textile yarns spiralled or braided around the tube (generally 4÷6 wire spirals or 1÷2 wire or tex-tile braids).

The actuator

The most frequent actuator met in hydraulic systems is a cylin-der. Cylinders may be single or double effect:

• Single effect cylinders consist in a tube in which a piston is pushed by the pressurised fluid. These applications generally use gravity to end their cycle and return to the start position. • Double effect cylinders have a piston with a non constant

diameter: for the whole length the piston's diameter is smaller than the internal diameter of the cylinder; generally in the centre of the piston the diameter is nearly equal so to have at disposal two surfaces to "convert" pressure in force. The circuit will direct the fluid to one or the other of the inlets moving the piston, in one or the other direction.

The cylinder bears two oil inlets at each end.

Single acting cylinders and Double acting cylinders are repre-sented in the schemes at side.

Other types of actuators, for example hydraulic motors, are currently used to transform hydraulic energy into mechanical power.

The fluids

The most common fluid is certainly water; yet most of the cir-cuits we are describing use oils to convey energy.

Actually the first systems used water and only with increasing complexity of technology oils started to be used.

The necessity to change came because water couldn’t assure the required properties: first of all a lubricant action, but also the absence of corrosive action and sediments, no evapora-tion at higher temperature and therefore a higher boiling tem-perature. These properties can be found with mineral oils. An oil pump can work at about 2000 cycles/1'. This means it can be directly connected to the motor. Using a water pump between it and the motor requires a speed reducer as the

11

fig. 5 - Single acting cylinders

fig. 6 - Single acting cylinders

fig. 7 - Double acting cylinders

fig. 8 - Double acting cylinders fig. 4 - Hydraulic motors

maximum number of cycles of this pump is about 200 (the motor can't work directly at such a slow rate).

The necessity of a reducer leads to greater sizes of the whole equipment creating space problems.

Furthermore while water causes oxidation and corrosion, oil protects the material of the pump assuring a longer life of the engines.

From a chemical point of view oils have generally higher boil-ing temperatures than water, so they can be used at higher intensity gaining productivity.

The difference in price purchasing oil instead of water is certain-ly covered by the advantages here mentioned.

The most common oil used in hydraulics is mineral based. Lately it is becoming necessary to use environment-friendly fluids. These fluids are bio-degradable and commonly called bio-oils. Their use is constantly increasing replacing mineral oils. Basically bio-oils can be divided in four families depending on the base material they are made of:

1. Polyethylene glycol base 2. Rape-seed oil base 3. Synthetic-ester base 4. Water based oil

1. Polyethylene glycol base - This family presents raw mate-rial available at a relative low price and a wide temperature range. Yet these oils are watersoluble so they can let water inside and damage the motors they are used for. Furthermore they are absolutely not mixable with mineral oils.

2. Rape-seed oil base - These oils have cheap raw materials as well and have a good compatibility with paints. Unfortunately the operating temperature range is not very wide due to bad working conditions at low temperatures and low stability at high temperatures. They are mixable with mineral oils but this mixability isn't very good.

3. Synthetic-ester base - Long life and a very wide tempera-ture range are the top performances of this family. Of course their price is higher than the others. The compatibility with the mechanics of hydraulic systems is also very good.

4. Water based oil - Water based oils are fire resistant, envi-ronmental friendly and acceptable. Their price is quite high, and present limited maximum service temperature.

Also water is still used in certain applications but mainly where it is directly used as working fluid and its consumption is sub-stantial: water cleaning and water blasting are examples where the pressurised fluid carries out its function and gets lost. The main difference between these two applications is the level of pressure at which the water is used.

12

While water cleaning applications utilise pressures from 100 to 400 bar, water blasting reaches 1450 bar and, water cutting even to 2000 bar. It's clear that the first is for domestic applica-tions while the second for industrial ones.

Important characteristics to define a fluid are its density and vis-cosity.

The density (usually identified by ρ) is the quantity of mass per volume and measured in kg/m3_.

Usually the reference is taken at 20°C and the value is about 870-900 kg/m3_{(water has} ρ = 1000 kg/m3_).

The viscosity is a measure of the resistance of a fluid to creep. Both kinematic viscosity ν and dynamic viscosity η can be used; their relation is η = ρν.

Kinematic viscosity is measured in centiStoke (cSt): 1cSt=10-6_m2_/s.

Dynamic viscosity in centiPoise (cP): 1cP=10-3_{N s/m}2_.

Hydraulic energy

Hydraulic energy is usually identified by the letter H and meas-ured in meters.

It can as usual be divided into two parts: potential energy and kinetic energy; the potential energy itself can be considered as due to position (identified by z) and to pressure. Kinetic ener-gy is due to the fluid’s velocity and goes with its square value. The corresponding equation is:

γ is the specific weight

The applications we are interested in, using hydraulic hoses, transfer energy under form of pressure; that is the second term of the equation above, remains the one to be considered. Just to give an idea about the importance of the three terms let's suppose a 4m long hose of 12,7 mm of diameter, operat-ing at 100 bar, with a water flow of 50 l/1’:

z can be at maximum 4m (hose completely vertical) 100 bar = 10000000 N/m2_;

γ = 1 kg/l = 9810 N/m3 --> p/γ = 1019 m

Q = 50 l/1’ = 0,000833 m3_/s

Q = v . πd2/4 --> v = 4Q/πd2 _{v = 6,58 m/s}

g = 9,81 m/s2 _{--> v}2_{/2g = 2,21 m}

It can be noticed how pressure energy takes part for 99,39 % to the total so it can be considered alone for any calculation.

A flexible conduit to transfer fluids or gases from one point to another is called hose assembly.

An assembly is basically built with the hose itself, and the extremity connections, solid couplings or fittings.

The hose is the flexible part of the assembly; its structure depends on the application and on the environment.

Basically the inner most part of the hose is the tube, winded up by a reinforcement and completed with a cover.

To connect the hose to the outer system and prevent leakage, dedicated fittings are used. They are put at each end of the hose and crimped to force a tight seal on the tube.

Fittings can be either permanent or reusable depending on the application.

The interface between hoses and fittings is a very important point in the design of the system: their functionalities are of utmost importance for a correct application.

Tube

As described above the inner part of a hose is the tube; its function is to contain and convey the service fluid. Furthermore it also protects the outer elements of the hose from the possible aggression of the conveyed fluid.

The material of the tube is chosen among a great number of synthetic rubbers. The chemical composition of the com-pounds should be selected to meet the requirements of the applications.

Basically there are some typical families of material assuring special properties; the following list shows the most used:

Reinforcement

The tube itself can surely not assure the resistance to the pres-sure of the conveyed fluid; in fact, as mentioned above, the design of the tube considers only its compatibility with the fluid to contain, while the very wide range of pressures present in hydraulic applications must be analysed otherwise.

BASICS OF HOSES AND ASSEMBLIES

14

HOSES DESCRIPTION

EPDM (Ethylene Propylene Diene rubbers)

High resistance to mineral and biodegradable oils and fuels Mineral oils resistant

Resistant to wide range of fluids High temperature, oil, fuel and chemicals resistant

Used for phosphate ester based fluids

This element was properly called reinforcement as its duty is to give pressure performance to the hose.

The type of reinforcement classifies hoses in two basic families: • Braided hoses

• Spiral hoses

The pressure resistance of the hose must be higher than the working pressure. The safety factor is defined as the ratio between the burst pressure and the max working pressure; for the hydraulic applications the safety factor is set to 4:1 by International Standards, some special static applications as water cleaning for example (ISO 7751) have 2,5:1 safety factor. For low pressure applications (up to 100 bar for example), tex-tile reinforcements may be used. So nylon, rayon or polyester fabrics are woven, braided or wrapped around the tube. When the pressure gets higher stronger materials are needed and steel wire spirals or braids are used.

Wire braided hoses bear generally one or two layers of rein-forcement (in some cases even three) while spiral ones have commonly four or six spirals (layers).

The application of braids and spirals can also be mixed depending on the most appropriate design.

Between each layer of braids or spirals an interlayer or breaker strip is put to create a bonding effect and to prevent frictional wear between the wires.

Cover

Environment, machines and operators themselves can damage the reinforcement. The cover, outermost element of the hose, is used to protect it.

There are several types of cover, each designed depending on specific requirements: economy, safety, abrasion resistance, chemical resistance, etc.; even aesthetics are features linked to the choice of the cover (e.g. colour).

Rubber cover can have wrapped finish: instead of the smooth finish a wet nylon tape is used around the hose during the vul-canisation; at last the nylon tape is removed and leaves the hose bearing its imprint.

Free steam vulcanisation is also used: the hose is directly vul-canised without any wrapping or shaping method.

The vapour steam at high temperature is directly in contact with the outer rubber cover of the hose.

This allows to save some steps of the entire manufacturing cycle saving time and materials.

Particular attention must be paid to maintain the tolerances and to avoid local defects on the cover.

Cover finish is smooth.

15

fig. 1 - Single braided hose

fig. 2 - Double braided hose

fig. 4 - Spiral hose (6 spirals)

Rubber cover Steel braid Rubber tube Rubber tube Rubber tube Inner breaker Adhesive rubber layer Adhesive rubber layer Rubber cover 2nd_braid 1st_braid Rubber cover

Body spiral carcass

Rubber cover

Inner breaker

Rubber tube

Adhesive rubber layer

Body spiral carcass

Also fabric braided cover are yet used: the cover is braided fabric, often impregnated with rubber adhesive. This is the best solution when minimum weight and heat dissipation are required. This solution is usually used on low or medium pres-sure hoses due to its relative weakness (e.g. R5 hose type). Coverless type is usually only used for stainIess steel braided hoses, mostly PTFE hoses.

17

HIGH PRESSURE HYDRAULICS: MAIN APPLICATIONS

Construction and public works • road pavers

• construction equipment • earth moving equipment

Well known applications use Manuli Rubber Industries universal product range. Tractor® _{hoses are widely used; for heavy}

applications Rockmaster®_{covers is better suited for high}

abra-sion resistance. On big machines the Manuli Rubber Industries Extreme product range is recommended in order to offer performances exceeding the standard requirements. Underground and open pit mining

• long wall support

• open pit mining equipment • drilling machine

For these applications Manuli Rubber Industries recommends Rockmaster®_{and Shieldmaster}®_{product ranges offering the}

highest abrasion resistance, flame retardant properties of the cover (MSHA approval, etc.), ozone resistance, cover shield. Energy

• off-shore oil platforms

The very severe atmospheric conditions require hoses with cover compounds offering particular characteristics, such as resistance to ozone and sea water. Manuli Rubber Industries recommends the use of the Extreme Product range in parti-cular NoZone hose are suitable for extended life exposed to harsh weather conditions and ozone attack.

Logistics

• port equipment • material handling

Applications working in continuous long term aging condi-tions, where hose flexibility and high abrasion resistance are required. Sometimes the twin hose version is requested. Industrial machines

• production machinery • injection moulding • steel works

• marine fleets

Applications with continuous long term aging conditions, where pressure rates and related peaks, together with the heavy mission profiles require heavy duty hoses with specifics well over the actual working pressures. The Manuli Extreme hose range is suggested.

Industrial and maintenance services • aerial platforms

• street cleaning machines • airport equipment

18

Applications with continuous long term aging conditions, where pressure rates and related peaks require, ozone, weather and abrasion resistance.

The Manuli Extreme hose range is suggested. Agriculture

• tractors

• combined harvester • implements

Light duty applications for which the Manuli Universal product range is fit for use.

Water blasting • cutting

• waste removal • descaling

Water blasting applications are growing in the industrial and construction sectors. A key factor for water blasting equipment is safety and key performances required are compactness, lightness, flexibility and high abrasion resistance.

The Manuli GoldenblastTM _{range is dedicated to these}

appli-cations

Water cleaning • industrial cleaning • paint removal

Water cleaning systems are used not only in the hobby appli-cations but also in industrial sectors such as: agriculture, food production, etc. Resistance to high temperature water and high pressure are required, together with abrasion resistance (for those hoses dragged along the ground).

Manuli Rubber Industries water cleaning offer is included in the Universal hose range.

Refrigeration applications • mobile refrigeration • bus air conditioning • off-highway vehicles a/c

Mobile refrigeration, bus air conditioning and off-highway vehicles air conditioning use special hose assemblies offered by Manuli Rubber Industries Refrigeration Connectors.

Braid

INTRODUCTION

This section is presented as a guide through the basics of hydraulic hose, fittings and assemblies to give the reader a better understanding of proper hose selection, care and use, as important component in modern hydraulic equipment.

RUBBER HOSE STRUCTURE

Traces of history and reasons of development

The first really flexible rubber hose, was developed during the 1870's. This was a rubber-coated canvass fire hose that was developed to replace leather hoses in use since the early 1600's. The first pressure rated hydraulic hose was on the mar-ket in the mid 1920's, but development still had a long way to go. The German Government did a lot to push development of a reliable hydraulic hose because of a need to be able to retract airplane landing gear to increase the plane's speed. This was the beginning and from then it has grown at a spec-tacular rate.

The primary reasons for this growth are:

• hydraulic systems can do more work and occupy less space than mechanical systems that use gears, pulleys, belts or chains;

• movement can be obtained between the various compo-nents when using flexible hose;

• hose will act as a system shock absorber while rigid steel tubing will not;

• hose will allow positioning of components almost anywhere; no required alignment as with conventional mechanical drives.

Hose structure

Hoses that are used to convey liquid and or gas under pres-sure are constructed in layers, and each layer is designed to fit a particular need in the overall performance requirement. Most hoses have at least tthree layers, which include the tube or inner liner, one or more layers of reinforcement and the cover. There are some hose types where the cover is also the reinforcement.

Tube

The tube or inner liner is generally made of some type of syn-thetic rubber or thermoplastic like nylon or polyester. The main function of the tube is to convey the liquid, gas or a combi-nation of the two. For this reason it must be chemically resist-ant to the Fluid conveyed. Always consult the Manuli’s chemical resistance information for proper selec-tion.

20

fig. 1 - One braid hose

cover

fig. 2 - Two braids hose

fig. 3 - Wire spiral hose

fig. 4 - Suction hose with helix wire

SAE 100R4 Helix Wire

reinforcement inner tube

Reinforcement

The reinforcement layer or layers, provide the strength to resist system pressure. They can be made from textile materials or wire. Some of the most common textile materials used are polyester, polyamide and aramide. Wire materials can be car-bon steel, stainless steel of different strength and thicknesses. There are three common methods of applying the hose rein-forcement. The most common is braiding, where the wire or textile materials are interwoven, to realise hoses from the low to high pressure range. For very high and ultra high pressure applications the reinforcement is generally applied in spiral configuration on the hose. Depending on the pressure range, multiple layers of reinforcement can be used. Another type of reinforcement is a combination of textile braiding and a helix wire inserted between the layers of braid. The helix wire pre-vents collapse under vacuum and is used in suction hose. (See Figures 1, 2, 3 & 4)

Cover

The cover, as the name implies is the outermost layer of the hose. It's main function is to protect the tube and reinforce-ment from external damage. Cover materials are selected based on their ability to resist abrasion, sunlight, chemicals and extreme temperatures with consequent ageing effects. Another function of the cover is to provide a place for the manufacturer to identify the product. This branding or layline, as it is called, will often contain the manufacturer's name, part number, pressure range or application, size, date of manufac-ture, industry specification, etc. A common industry specifica-tion on hydraulic hose would be an ISO or SAE rating.

HYDRAULIC HOSE INTERNATIONAL STANDARDS

In order to have a better understanding of the selection crite-ria for engineering, design and structure of hoses, it is useful to introduce the main International Standards for wire braided and wire spiral hoses.

Generally speaking, Europe and the markets traditionally linked to Europe have the tendency to refer to EN standards, while American markets and the market traditionally linked to America have the tendency to refer to SAE standards.

Both standards specify the minimum requirements and char-acteristics for all the different categories of hoses; among oth-ers, these are the ones relevant to the scope of this manual:

The norms specify mainly:

• the physical dimensions (internal, external diameters, cover thickness etc.)

• hydrostatic requirements as the maximum working/burst pressure

• the minimum bend radius

• the testing and qualification requirements.

In an effort to consolidate all norms, ISO standards are designed to merge both SAE and EN. Gradually ISO specifications are going to take place in the whole market:

22

*

Manuli Rubber Industries has a wide range of products that covers all specifications of the international standards.

EN and SAE standards do not cover all the requirements in the market. Therefore Manuli Rubber Industries also manufactures hoses that have characteristics well beyond the international specifications. 23 ISO Standard Wire Braid Textile Wire Spiral Current EN Standard Traditional International Standard Manuli Hose Line ISO 1436 - 1 ST ISO 1436 - 1 SN ISO 1436 - 2 ST ISO 1436 - 2 SN ISO 1436 - R1A ISO 1436 - R1AT ISO 1436 - R2A ISO 1436 - R2AT ISO 11237 - 1 SC ISO 11237 - 2 SC ISO 11237 - R16 ISO 11237 - R17 --ISO 4079 - 1TE ISO 4079 - 2TE ISO 4079 - 3TE ISO 4079 - R6 ISO 4079 - R3 ISO 3949 - R7 ISO 3862 - 4SP ISO 3862 - 4SH ISO 3862 - R12 ISO 3862 - R13 ISO 3862 - R15 EN 853 - 1 ST EN 853 - 1 SN EN 853 - 2 ST EN 853 - 2 SN --EN 857 - 1 SC EN 857 - 2 SC --EN 854 - 1 TE EN 854 - 2 TE EN 854 - 3 TE EN 854 - R6 EN 854 - R3 EN 855 - R7 EN 856 - 4SP EN 856 - 4SH EN 856 - R12 EN 856 - R13 --DIN 20022 - 1 ST DIN 20022 - 1 SN DIN 20022 - 2 ST DIN 20022 - 2 SN SAE J517 - 100R1A SAE J517 - 100R1AT SAE J517 - 100R2A SAE J517 - 100R2AT --SAE J517 - 100R16 SAE J517 - 100R17 SAE J517 - 100R5 SAE J517 - 100R4 DIN 20021 - 1TE DIN 20021 - 2TE DIN 20021 - 3TE SAE J517 - 100R6 SAE J517 - 100R3 SAE J517 - 100R7 DIN 20023 - 4SP DIN 20023 - 4SH SAE J517 - 100R12 SAE J517 - 100R13 SAE J517 - 100R15 Tractor / 1T Rockmaster / 2ST Tractor / 2T Harvester / 1T Harvester / 2T Tractor / 1K Tractor / 2K Lyte-Flex Harvester / 17 Cover Spyrtex / K Multitex Astro / 2 Astro / 3 Multitex Adler / 2 Hydroplast Goldenspir / 4SP Goldenspir / 4SH Goldenspir / 12 Goldenspir / 13 Rockmaster / 15

Proper hose selection is critical in order to realise a safe hydraulic system. The first step in having a safe hydraulic sys-tem is selecting components that meet the needs. Compromises in hose selection may create situations of dan-ger, as well as affect the performance and durability of the sys-tem. The choice may work for the short run, but may not be a good long-term decision.

The most important target in this activity is the safety. Many interacting factors influence the hose service life and the ability of each fluid-power system to operate satisfactorily. The combined effects of these factors on service life are often unpredictable.

Each system has to be carefully analysed in order to proceed with a proper hose and related components selection, to cor-rectly design routings, to meet the system performance and reliability (hose service life requirements), and to minimise the risks of personnel injury and/or property damage. The “SEVEN EASY STEPS” is a useful method that must be carried out for a preliminary analysis of the critical factors.

An effective way to remember the hose selection criteria is to remember the word STAMPED, acronym of:

S = Size T = Temperature A = Application M = Material to be conveyed P = Pressure E = Ends of coupling

D = Delivery (flow rate and fluid velocity). Hose Size (Dash numbers)

The inside diameter of the hose must be adequate to keep pressure loss to a minimum and avoid damage to the hose due to heat generation or excessive turbulence. Dedicated nomographics for pressure loss and fluid velocity can be used to determine the most proper hose size following the over mentioned criteria. Alternatively the traditional calculation schemes are also available on the Manuli web site.

In case of substitution of a hose on field applications, read the hose size on the branding of the original hose; in case the original hose branding is worn off, the original hose must be cut and inside diameter measured for size.

Remark

Before cutting an original hose assembly, measure the overall assembly length and fitting orientation. These measures will be necessary to build the replacement assembly.

24

The hose size numbering systems

Different hose size numbering systems are currently used by hose manufacturers to identify hose sizes:

• the “dash” numbering system: the I.D. (Inside Diameter) of the hose is expressed in 1/16-inch increments. The dash size coincides with the number of 1/16-inch increments of the hose I.D.

• “inch” and corresponding “mm”

• also the DN (Nominal Diameter) ref. ISO 4397 in mm are currently used as reference.

For example 3/8” ID=6/16 inch therefore the dash size is –06. The corresponding value in mm is 9,53mm, the Nominal Diameter by ISO 4397 is 10.

Exceptions to the hose size numbering system are PTFE hoses and SAE 100R5 hoses (see the scheme here below).

25

Standard hydraulic hoses (ref. ISO 4397) Inches

Dash No. mm Inches mm

R5 and PTFE hoses

---4.8 6.4 7.9 10.3 12.7 15.9 --- 22.2 28.6 34.9 46.0 --- 60.3 --- --- --- ---3/16 1/4 5/16 13/32 1/2 5/8 --- 7/8 1 - 1/8 1 - 3/8 1 - 13/16 --- 2 - 3/8 --- --- --- ---3.2 5.0 6.3 8.0 10.0 12.5 16.0 19.0 - 25.0 31.5 38.0 51.0 - 63.0 76.0 89.0 102.0 -1/8 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1 1 - 1/4 1 - 1/2 2 2 - 1/4 2 - 1/2 3 3 - 1/2 4 4 - 1/2 -2 -3 -4 -5 -6 -8 -10 -12 -14 -16 20 -24 -32 -36 -40 -48 -56 -64 -72 Hose I.D.

The hose size numbering system

Hose is sized

on I.D. Hydraulic Tubingis sized on O.D.

SAE 100R5

Their size is designated by the tubing O.D. dash size which they would replace. PTFE and SAE 100R5 hoses have the same I.D. as that of the equivalent dash size hydraulic tubing (SAE 100R5 hose type was the first hydraulic hose developed to replace rigid tubing: that’s why it remains traditionally iden-tified with the same sizing as tubing).

See the enclosed table of correspondence.

In order to select the hose ID, which suits the flow rate of oil being pumped through the hydraulic system, the nomograph provided in this Technical Manual can be used.

This diagram will help you to calculate the optimum hose diameter starting from 2 known values:

a) max. recommended fluid velocity b) flow rate of your system

As the correct fluid velocity choice is important to avoid turbu-lence and excessive pressure loss (for suction lines the poten-tial pump cavitation must be considered). Manuli reports the following maximum recommended values:

Max. fluid velocity limits m/sec.:

• Pressure lines up to Max. 8-10 m/sec. • Return lines up to Max. 3-4 m/sec. • Suction lines up to Max. 1,5 m/sec. See also ISO 4413 specification

26

Nominal diameter calculation

l / m 500 400 350 300 250 200 150 100 70 60 50 40 30 20 10 5 4 3 2 1 100 75 50 40 30 20 10 5 4 3 2 1 0,5 0,4 0,3 0,25 4 ” 3 ” 2 ” 1 1/2” 1 1/4” 1 ” 3/4” 5/8” 1/2” 3/8” 5/16” 1/4” 3/16” DN 102 DN 76 DN 51 DN 38 DN 31,5 DN 25 DN 19 DN 16 DN 12,5 DN 10 DN 8 DN 6,3 DN 5 0,1 0,2 0,3 0,4 0,5 1 1,5 2 3 4 5 6 8 10 0,5 1 1,5 2 2,5 3 3,5 4 5 6 7 8 9 10 15 20 gal / m m / s ft / s Velocity Flow Rate Diameter

Knowing the flow rate of your system draw a line from this point to the limit velocity and read the intersection with the diameter line, the first upper value can be chosen for your system. For example 70 l/1’ for pressure lines leads to a choice of DN 19 (3/4”) considering maximum fluid velocity 5 m/s; 30 gal/1’ for return lines need DN 38 (1-1/2”)

Unlike hoses, hydraulic tubing is sized by its O.D. (Outside Diameter). The number of 1/16-inch increments in its O.D. represents its dash size.

Temperature

When selecting a hose, care must be taken to ensure that the system fluid and ambient tempera-tures, both static and transient, do not exceed the limitations of the hose.

Operating temperatures specified refer to the maximum temperature of the fluid being conveyed. High heat conditions may have an adverse effect on hose due to degradation of the rubber which will limit hose usefulness and reduce fitting retention.

In some cases the fluid being conveyed will slow down this degradation whereas other fluids may accelerate it. Therefore, the maximum temperature of each hose does not apply to all fluids.

Continuous use at maximum temperatures or near the maximum rated temperatures will materially reduce the service life of the hose (e.g. ref. DIN 20066, SAE J1273, etc.) and should always be avoided. Continuous use at or near the maximum temperature rating will cause a deterioration of physical properties of the tube and cover, deterioration that will reduce the service life of the hose. Also the external ambient temperature must be carefully con-sidered:

• extreme cold environmental temperatures for the potential hose cracks due to bend efforts;

• extreme hot ambient temperatures, in presence of irradia-tion inside engine compartments, etc.,may have a high ageing effect on the rubbers.

Most standard hydraulic hoses are designed to operate in the temperature range between -40°C (-40°F) and +100°C (+212°F), range generally considered as standard.

But also other categories of hoses exist: some hoses manufac-tured with special rubber compounds are designed to operate between:

• -40°C (-40°F) and 121°C (250°F): range considered high temperature

• -55°C (-67°F) and 150°C (+300°F): range considered extended temperature, etc.

For example, for extended temperature range applications use Manuli EQUATOR™ hose (see the Manuli temperature range categories).

When selecting a replacement assembly, the same considera-tions must be applied: fluid temperature and ambient temper-ature must be carefully considered. The hose selected must be capable of withstanding the minimum and maximum temper-ature seen by the system. Care must be taken when routing near hot manifolds: in extreme cases, heat shield may be advis-able.

Additional information and limits on Manuli Rubber Industries hydraulic hoses temperature ranges referred to specific fluids must be checked on the catalogue or contacting Manuli Rubber Industries specialists.

Application

When selecting a hose, it is basically important determining where or how the hose or assembly is to be used. To fulfil the requirements of the appli-cation, additional questions may need to be answered, such as:

• where will the hose be used? • equipment type and mission profile? • fluid and ambient temperature? • working and surge pressures? • minimum bends radius? • excessive flexing movement? • fluid compatibility?

• environmental conditions? • external abrasive stress? 28

ST

Standard Temperature 125 peaks

-40 100 continuous

Three main categories of temperature range

HT

High Temperature 135 peaks

-40 121 continuous

ET

Extended Temperature 150 peaks

29 • what about vibrations?

• hose flexibility/structure?

• coupling termination end type and thread type? • suction or return line application?

• routing requirements?

• safety and industry specifications to be met?

• external mechanical loads and/or unusual forces that need to be considered

• antistatic and/or flame retardant cover requested? • critical nature of the application (e.g. mines, etc.)

Let’s consider for example the harsh conditions covers, often cause of failure. In general covers of hoses are subject mainly to abrasion and ozone attacks. Working life can be substan-tially reduced in conditions where the cover of the hose is dragged against hard rough surfaces. The work in mines for example or in some industries where the hose is rolled on pulleys or rubbed against sharp angles is very demanding. In this conditions standard covers are not recommended. Rockmaster®_{is a heavy duty hose line specially engineered for}

applications such as marine & off-shore, forestry and mining. Shieldmaster® _{is a hose line with characteristics of abrasion}

resistance even more extreme!

Under ISO 6945 abrasion resistance test, Rockmaster® _cover

outperformed the standard requirements by an order of mag-nitude specifications requirements and Shieldmaster® _cover

was so resistant that the result has lost significance: the cover offers a resistance at least 1000 times higher than required by standards.

In any case it is important always to ensure that the hose is fit for the intended purpose.

Ensure also that the selected hose and fittings are either com-patible or protected from the specific environment to which they are exposed: severe environmental conditions such as salt water, chemicals, air pollutant, ozone and sunlight, etc. can cause degradation and lead to premature failure.

0,6 0,5 0,4 0,3 0,2 0,1 0 0,50 0,25 0,05 0,01

_<0,001

_<0,001

_<

_<

_<

_<0,001

Abrasion Resistance ISO 6945 (2000 cycles, 2,5kg)

OFFERS

AT LEAST 1000 TIMES

HIGHER RESISTANCE THAN STANDARD

In order to support application engineers to carry out their application analysis, a useful scheme is here enclosed as a guideline. It is also useful for field test analysis.

Even though each application must be carefully analysed, these are some general guidelines for the Manuli product selection criteria and application families:

Hydraulic earth moving machines

The standard product are generally fit for use. The extreme products meet and exceed the requirements. On big machines the extreme products must be preferred.

Hydraulic agriculture machines

Light duty applications: the standard products are fit for use. Hydraulic mobile equipment (trains, trucks, etc.)

They are very particular applications, where the pressure plays a secondary role while the ozone, vibrations at high frequency, high temperature, powder, mud, water and cleaning water jetting with aggressive detergents require the use of the Extreme hose range with eventually external protections. Hydraulic continuous long term aging (industrial machines, etc.)

Let’s take as reference the world of the presses (moulding machines, etc.), where the pressure rates and the related peaks, the heavy mission profiles (continuous 24 h per day), etc. require selection of hose overdesigned respect to the actual working pressures, because of the long term aging conditions. Hydraulic systems on marine and off shore applications The atmospheric conditions very severe require hoses with cover compounds with particular characteristics, like the resist-ance to ozone and sea water. The extreme products are for sure the most indicated. Stainless steel fittings are generally requested for naval and marine applications.

Mining applications, underground and open-pit mines Critical applications. Recommendations: Extreme products high abrasion resistant, flame retardant property of the cover, skive fittings, avoid very small diameters, robust fittings, etc. Forestry machines

Critical applications: high abrasion resistant cover, resistance to high pressure, fatigue and twist, low bend radius, 3/4” and 1” are the most common used sizes and 1/2” also. Wire spiral solutions are suggested for the most severe conditions. Lift

Large size braided hoses are fit for use. 30

31

Field analysis data

Customer

Machine

Hose

Fittings

Working pressure Static

Fix Weather Abrasion Environmental Ozone Industrial cleaning Dynamic Flexing Certification requested Industry Near the fittings? Transportation Agriculture Earth moving

Working pressure max/min Pmax bar Pmin bar

bar bar m/sec per hour mm mm theoretical effective l/min. bar Pump press.

MINERAL BIO mi -1 P P T hrs/day ∞C T ∞C h Pressure peaks Impulse frequency Fluid velocity Oil

Medium oil temperature

Working time

Installation

Anverage nr. of flexing

Min. bend radius

External temperature

Environmental conditions

Date Name

Relief valve setup

Total working

time h

Vibrations

(frequency Hz, amplitude +/- mm)

32

Material to be conveyed

Some applications require special oils or chemicals to be conveyed through the system. Hose selection must assure compatibility of the hose tube, cover, couplings and O-Rings with the fluid used. Additional caution must be used in hose selection for gaseous applications such as refrigerants, compressed air or LPG, etc. When selecting a hose for gaseous applications where permeation of fluid through the hose wall may occur, consider the possibility of hazardous effects, such as explo-sions, fires and toxicity. Refer also to applicable standards for specific applications such as refrigerants. If fluids permeate through the hose tube, consider the use of perforated covers to prevent fluid cover blistering under the cover (pin-pricking). Also ensure the compatibility of the system fluid not only with the hose tube, but also with the braid, cover, fittings and other components since permeation may expose the entire hose assembly to the system fluid.

Regarding the hydraulic fluids, mineral & biological oils, Manuli wire braided and wire spiral hoses have a wide inner tube compatibility: spiral hoses are also identified by the BIO logo on the hose lay-line. Anyway each single oil brand name has to be carefully checked, seen the wide differentiation of the additive packages used by many hydraulic oils producers in their fluids. That’s why an intense activity of oil compatibility is currently performed on the Manuli rubbers, as support to customers and OEMs.

The hose selection activity must ensure compatibility mapping of the hose tube, cover and fittings with the type of fluid to be conveyed. If the end fitting type requires an O-Ring for sealing, ensure that the O-Ring compound is also compatible with the system fluid.

For tube compound evaluations, please refer to the Manuli Rubber Industries Approved fluid compatibility chart following the evaluation criteria supplied here below reported. For spe-cific information, contact Manuli Rubber Industries.

For the mineral and biological oil classification you can refer to the following table, summarising the main characteristics of each family, advantages and disadvantages, and cost estima-tion compared to the tradiestima-tional mineral based.

33 For particular or unusual fluids check compatibility together

with MRI’s specialists.

Pressure

Knowing the system pressure, including pressure spikes, surges, etc. is of the greatest importance for the hose selection process. The hose catalogue working pressures must be equal to or greater than the system pressure, including peaks. Pressure spikes greater than the published working pressure will shorten hose life and must be taken into consideration (e.g. ref. SAE J1273). Pressure peaks must be measured with electronic devices capable to record very short transients not measurable with traditional analogical instruments.

The rated pressure of primary and eventual secondary valve of the system gives an additional information of what can be the maximum pressure peak inside the system. The Max working Hydraulic oils classification

Mineral oils Oil Family Low: -40 ∞C High: +150 ∞C Oper. Temp.

• The traditional solution, widely industrially available, suitable for the majority of relevant applications

• Low cost if compared to alternative solutions

Advantages

• Not ecologically acceptable 1

Cost Disadvantages Natural oil based Rape-seed HETG Low: -30 ∞C High: +80 ∞C

• Suitable for the majority of relevant applications

• Limited by their poor oxidative thermal and hydrolitic stability • May bio-degrade in the system: the oil stability is very susceptible to water contamination • Possible strong odours in use and formation of gums

2 to 3 Water based fluids HF HF-A Low: -5 ∞C High: +60 ∞C HF-C Low: -40 ∞C High: +60 ∞C

• FIRE RESISTANCE hydraulic fluids • Similar applicability than polyglycols • For their high water content they can be considered ENVIRONMENTAL FRIENDLY & ACCEPTABLE

• Moderate hydraulic fluid properties 3 to 6 Polyglycols (HEPG) PEG PAG PPG Low: -50 ∞C High: +130 ∞C

• Limited to areas where water solubility is advantageous, for example, inland waterways, spillage of non soluble products results in a perceivable surface film • Areas where cleaning by simple water washing is employed may also benefit

• Due to the high water solubility their use is somewhat limited or prohibited (Switzerland) due to the risk to pollute the water-bearing stratum • Absorbed water can effect the performances 5 to 7 Synthetic esters HEES Low: -30 ∞C High: +90 ∞C

• Better stability than vegetable oils, wider range of successful applications

• Diesters: used mainly in aviation, automotive, compressor applications

• Hindered esters: application similar to diesters and also steel rolling or industrial hydraulic

• Stability can be affected by water contamination

• The high cost tends to limit their use

6 to 10

The hydraulic hoses of the Manuli product range are not designed for immersion in the service fluid. This type of special applications should be avoided or care-fully studied with additional external protections for the hoses, selection of special hose types, e.g. with thermoplastic cover and validation on the specific appli-cation. The turbulence of the fluid, the high temperature and nature of the fluid as well as other elements may impact the properties or integrity of the hose cover material (the cover compound of the hose is designed may impact the properties or integrity of the hose cover material (the cover compound of the hose is designed to resist to oil drops and extrernal agents, not immersion in the service fluid). For more detailed information conact Manuli Rubber Industries.

pressure inside the system in fact cannot be simply equal to the pump rated working pressure, but must consider also the functional activities of the equipment (negative loads, vibra-tions, etc.) and the consequent pressure peaks.

Be aware that hydraulic fluid under pressure can be potential-ly dangerous!

• An explosive bursts or stream of escaping fluid can cause damage to equipment or serious injury to persons nearby • Highly pressurised fluid escaping from a small pinhole can

be almost invisible and yet exert extreme force capable of penetrating the skin and other tissue, causing possible severe injury

• Pressurised fluids, if released uncontrolled, can exert an explosive force

• Hot fluids or chemicals can cause severe burns • Some fluids are highly flammable, etc.

The maximum rated working pressure of any assembly will be defined by the lowest working pressure of the hose, the end fitting or any adaptor (consequently it is recommended to select the proper cou-plings and adaptors with working pressure higher or equal to the hose one, never lower). Always take into consideration any pressure spikes or potential pressure surges in the system, but also the fatigue mission profile of the application, number of pressure impulses per hour/day/year, in order to proper pro-vide eventual oversizing of the hose reinforcement compared to the minimum theoretical requirement. In particular also the position of the hose inside the system must be considered, seen the different functions: see the following scheme and mission profiles of the applications.

34 Hose WP selection hose WP system pressure history system WP time spikes P

"The hose working pressure should include the pressure surges (spikes) that, even if not indicated on many common pressure gages,

must be identified on electronic measuring instruments with a high frequency response"

35

Pressure (Power) lines

High pressure, may be also over 400-500 bar Fluid velocity: Max. 8-12 m/s

Heavy duty working conditions (high fatigue stress) can be present, Manuli wire spiral and two wire braids hoses are generally requested

Suction lines

Low pressure (max 5-10 bar)

Fluid velocity: Max. 1,5 m/s (to avoid pump cavitation) Resistance to vacuum is requested up to -0,83/-0,90bar Large I.D. requested to reduce pressure drop

Spirtex/K and two wire braided hoses are designed for this applications and in particular for vacuum resistance

Drain lines

Low pressure (Max 20-30 bar) Fluid velocity: Max 3-4 m/s Small bend radius requested

Large I.D. requested to reduce pressure drop Return lines

Low pressure (Max 30-50 bar) Fluid velocity: Max. 3-4 m/s Small bend radius requested Vacuum resistance

Large I.D. requested to reduce fluid velocity and pressure drop Multitex and Astro hoses line generally suitable

For a proper hose selection in terms of pressure resistance, it is also useful to consider the following working pressure classification, with progressive fatigue stress and consequent necessary design criteria:

• low pressure up to 70 bar • medium pressure up to 210 bar • high pressure up to 210-350 bar • very high pressure up to 350-420

bar or higher

Pilot lines

Medium pressure (Max 100 bar) Fluid velocity: Max. 5 m/s

Compact dimensions & flexibility are a “must” Small bend radius requested

Lightness is appreciated

The Manuli solution for pilot lines is Pilot hose

Ends of coupling

Select the proper end fitting from the Manuli cata-logue, being careful to the maximum working pressure of the termination end (by the reference international specifications), in consideration of the hose to which it is applied.

Additional considerations of mechanical robustness and seal-ing capabilities of the termination ends can be advisable for heavy duty applications and/or specific installations: refer to the coupling selection criteria supplied in the relevant section of the manual; contact Manuli Rubber Industries for specific detailed information.

When replacing an assembly, identify end connections and sealing surfaces. Once thread ends have been identified, con-sult the appropriate section of the Manuli Rubber Industries catalogue for specific part number selection.

Do not mix and match hose and fittings from different suppliers: in fact relevant testing qualification programs are necessary to validate the hose and fittings compatibility. Hydraulic hose from one supplier is seldom compatible with fittings from another; in any case the assembler is responsible for the guarantee of proper compatibility existing between the hose and fitting if the manufacturer prescriptions are not correctly followed.

Ensure that the correct inserts and ferrules are chosen for the hose type.

Delivery (Flow rate and fluid velocity)

When replacing an assembly, we can assume the system is properly sized to efficiently transport fluid, that’s why the same I.D. of the original hose can be used.

Eventually it can be useful to determine if the system is properly sized to efficiently convey the max. flow rate: in this case follow the recommendations below.

If the system is new or altered, determine the hose I.D. needed to convey the max. flow rate considering the maximum recommended fluid velocities for each application type (pres-sure lines, return lines, suction lines) and a max. pres(pres-sure loss inside the line, in order to avoid excessive friction, vibrations 36

37 and heat generation. The use of Nomographic Charts or

cal-culation schemes (see Manuli web site tool and the enclosed table) can be useful to determine the minimum size needed for the application, ensuring that the required system flow rate is available avoiding excessive pressure drop from occurring. Data needed to determine pressure drop are:

• Fluid type (specific gravity) and viscosity

• Fluid temperature (in order to calculate the correct viscosity value)

• Flow rate

• Hose size and length • Number and type of fittings

The traditional formula from hydraulics is the following:

dimensionally:

λt = friction factor (generally close to 0,03 for rubber smooth tube hoses. It is an adimensional coefficient). λt depends on viscosity and therefore on the fluid temperature.

l = length of hose (m)

= fluid density (volumetric mass : kg/m^3) v = fluid velocity (m/s)

d = Inside Diameter (m)

In addition the following parameters are requested: ν = fluid viscosity (cSt): to determine the friction factor Q = flow rate (l/minute) to determine the fluid

See the following table reporting pressure loss data for the most common applications.

38

viscosity (cSt) 20 - oil specific gravity 0,85

diameters (mm) flow (l/m) 1 2 5 10 15 20 25 30 40 50 100 200 300 400 500 600 700 800 900 1000 4,8 0,216 0,433 1,082 3,457 6,3 0,073 0,146 0,364 0,729 1,931 3,195 8,0 0,056 0,140 0,280 0,421 1,027 9,5 0,028 0,070 0,141 0,211 0,454 0,671 0,923 1,528 12,7 0,044 0,066 0,088 0,169 0,233 0,385 0,568 1,912

See also the calculation tool on www.manuli-hydraulics.com

16,0 0,026 0,035 0,044 0,078 0,128 0,190 0,638 2,147 19,0 0,018 0,022 0,026 0,057 0,084 0,282 0,949 1,930 25,4 0,007 0,008 0,011 0,021 0,239 0,486 0,804 1,188 1,635 31,8 0,006 0,024 0,082 0,167 0,276 0,409 0,562 0,736 0,930 1,143 38,1 0,010 0,035 0,071 0,117 0,173 0,238 0,312 0,394 0,484 0,582 50,8 0,003 0,009 0,018 0,030 0,044 0,061 0,080 0,100 0,123 0,149

Pressure loss (bar) per meter of hose

Table of oil viscosity according to temperature 3000 2000 1000 500 300 200 100 50 30 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 200 20 15 10 8 6 5 4 3

Note: Oil viscosity decreases when the temperature increases

Temperature °C Viscosity mm 2/s 1 2 3 4 5 6 7 1) ISO VG 320 2) ISO VG 150 3) ISO VG 68 4) ISO VG 46 5) ISO VG 32 6) ISO VG 22 7) ISO VG 16

39 Hose, Connectors & Adaptors Handling,

Storage & Traceability – Hose

It is well known that, with time, rubbers age and their physical properties change. Eventually, the same rubbers can lose their optimal characteristics for the applications to which they are dedicated.

Consequently the targets for the storage methods of rubber based products are aimed to avoid or reduce at minimum level the aging of rubbers:

• reduce the storage period to a minimum, considering rub-bers are subjected to ageing with time;

• guarantee the best storage conditions, carefully considering all the main parameters influencing the ageing process. Also, hose storage requires particular conditions for the best results in maintaining the products initial properties and characteristics.

The following table lists the main specifications regarding storage conditions for hoses:

specification issue date

ISO 8331 Ed. September 1991 - New Release 2007 BS 5244 Ed. 1986, reaffirmed 1996

DIN 20066 Ed. October 2002 SAE J1273 Ed. August 2004 Summary of their recommendations:

ISO 8331: Rubber and plastics hoses and hose assemblies – Guide to selection, storage, use and maintenance

Max. storage duration

<4 years before assembly operation <2 years for hose assemblies

If further storage periods cannot be avoided, hoses should be inspected and/or tested before use (tests are not specified). This specification does not state any max. service life duration for the hose assembly.

The new release of 2007 doesn't report any storage life duration requirements and refers to ISO 2230.

ISO 2230: Rubber products - guidelines for storage

Not specific for hoses but for rubber goods, classified in 3 groups (A, B, C).

Manuli products are classified as B, with this storage requirement: • 7 years as initial storage period

• 3 years as possible extension after test

STORAGE AND SHELF LIFE CONDITIONS

4 years maximum age of hose material production date hose material production date assembly 2 years maximum storage duration 6 years maximum utilisation

limit of hose line

fig. 1 - Hose storage and utilisation limits according to DIN 20066, part 5.

40

DIN20066: Hydraulic fluid power; hose assemblies; assessment of service performance (fig. 1)

Max. storage duration

<4 years before assembly operation <2 years for the assemblies

Stress conditions are quoted which are potentially able to reduce the hose assembly service life.

A max. functionality period of 6 years is indicated including the storage period as assembly. As a consequence each storage period consumes an equivalent part of the service life of the hose. BS 5244: Application, storage and life expiry of hydraulic rub-ber hoses and hose assemblies

Max. storage duration for hoses and assemblies <3 years: no tests required on the hose

• 3 - 5 years: hydraulic proof pressure tests required

• 5 - 8 years: hydraulic proof pressure tests, impulse test, burst test, cold flexibility test, electrical test required

>8 years: hose to be scrapped

Max. storage duration for assemblies installed on stored equip-ment

<3 years: no tests required on the assemblies

• 3 - 5 years: hydraulic proof pressure and burst test required >5 years: assembly to be scrapped

The service life duration of a hose assembly is quoted as being “dependent on the equipment” (to which the hose has been fitted), therefore stating that a general estimate is not possible. It advises that “records be kept for each type of equipment with a view to establishing a working life for each particular application”.

SAE J1273: Recommended Practices for Hydraulic Hose Assemblies

Max. storage duration Rubber hose:

<10 years in bulk form

<10 years for assemblies passing visual inspection and proof test Thermoplastic or PTFE hoses: considered unlimited

The specification reports general requirements on factors that can affect hose products in storage.

The specification does not give indications on hose assembly service life duration, stating that it is unpredictable, considering the combined effects of all the factors involved. Each system has to be carefully analysed for the purpose.

The specification gives general criteria for a maintenance pro-gram of hose assemblies, to be carried out by the users. The maintenance program must suit the specific application and each specific hose on that application.

The specification asks to evaluate factors such as the nature and severity of the application, past history, etc., to establish the frequency of visual inspections and functional tests.