TECHNICAL MANUAL
ISSUED BY
INDEX 1. INTRODUCTION • Introduction • Warning on safety
www.manuli-hydraulics.com
[email protected]
3 4 6
2. BASICS OF HYDRAULICS • Hydraulic systems and fluids • Basics of hoses and assemblies • Hoses description • High pressure hydraulics: main applications
9 10 14 14 17
3. 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
19 20 20 22 24 39 41 43 47
4. 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
49 50 53 55 56 60 62 64 66 66 71 74 76 77 78 79 82 84 85
5. 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
91 92 92 96 97 98 98 98 101 101
6. QUICK COUPLINGS • Introduction • QSafe applications • Structure of a quick-coupling • QSafe product range • QSafe part numbering system
103 104 104 105 108 113
7. REFRIGERATION • Refrigeration applications • Hoses and fittings • Refrigerants and lubricants • Specifications
117 118 120 123 123
8. HOSE ASSEMBLY • Hose assembly data • Cleaning, inspection, testing • Hose assembly installation tips • Hose protection • European legislation on safety and conclusion
125 126 128 129 131 134
9. MAINTENANCE • Maintenance • Periodic inspections • Hose assembly troubleshooting guide
135 136 137 140
10. APPENDIX • System of units and conversion • Glossary • Type approvals
147 148 152 165
Introduction
INTRODUCTION
4
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.
Remark 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 communication channels.
FLUID CONNECTORS PRODUCT RANGE
All Manuli hydraulic products will provide you with a long service 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 maintenance 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 configurations, etc. This booklet suggests how to study the applications, 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 operating condition at any times, minimising 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 preventive 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;
ENGLISH / ESPAÑOL
• regularly scheduled inspections; • troubleshooting (identifying problems and solutions); • well-trained personnel. Additional technical information on components and accessories, 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. Safety applications training
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.
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WARNING ON SAFETY
6
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 pressurised 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 pinhole in the hose, can easily penetrate the skin. If this happens, seek medical assistance immediately. Fluid injections are considered a serious injury requiring prompt medical attention. Leak Leaking hydraulic fluid is hazardous. In addition to making workplace floors slippery and dangerous, leaks also contaminate 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 potential energy or absorb shock. This energy can create pressure that keeps the system’s components moving. Charged accumulators 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.
Due to the serious criticalities of hydraulic applications it is important to select and install assemblies with proper criteria: • select proper hose assemblies for the application, considering the numerous factors and conditions affecting the functionality and technical ability of the hose to meet the requirements; • hose assembly routing must not create an injury hazard or damage to the hose; • select hydraulic components so that the application's temperature, 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 qualification 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 applications; 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 equipment (historical data) • record maintenance data regarding inspections and testing or substitution of assemblies, etc. • only properly trained personnel should inspect, test or service 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;
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• 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 pressurised hydraulic components; • be aware that some hydraulic fluids are highly flammable.
J1273
Refer to SAE J1273 par. 4 specification for further details on safety aspects. Recommended Practices for Hydraulic Hose Assemblies
Basics of Hydraulics
HYDRAULIC SYSTEMS AND FLUIDS
10
Energy transmission systems Motors supply mechanical energy. An electric motor gets its motion from an electric flow of energy, 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.
Load
Actuator
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.
Pump
Motor
Any mass can have potential and kinetic energy; a fluid can also "transport" it from one point to another. Tank
For example, waterfalls take advantage of the potential energy linked to the different heights at which the water is before and after the transmission.
fig. 1 - Hydraulic circuit with cylinder Load
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).
Cylinders discharge lines potential criticalities for hose assemblies: negative load surges Pump outlets potential criticalities for hose assemblies: - pressure surges - vibration - temperature - severe installations
fig. 2 - Basic hydraulic circuit
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 themselves and a flexible hose suits at best the needs. Moreover, using fluid transmission mainly in engines operating
fig. 3 - Hydraulic cylinders
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.
fig. 4 - Hydraulic motors
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 textile braids). The actuator The most frequent actuator met in hydraulic systems is a cylinder. 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.
fig. 5 - Single acting cylinders
• 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.
fig. 6 - Single acting cylinders
Single acting cylinders and Double acting cylinders are represented 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 circuits we are describing use oils to convey energy.
fig. 7 - Double acting cylinders
fig. 8 - Double acting cylinders
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 evaporation at higher temperature and therefore a higher boiling temperature. 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
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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 boiling temperatures than water, so they can be used at higher intensity gaining productivity. The difference in price purchasing oil instead of water is certainly 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 material 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 temperature 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, environmental 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 substantial: 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.
fig. 9 - Pump
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 applications while the second for industrial ones. Important characteristics to define a fluid are its density and viscosity. 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/m2. Hydraulic energy Hydraulic energy is usually identified by the letter H and measured 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 energy 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, operating 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 --> v2/2g = 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.
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BASICS OF HOSES AND ASSEMBLIES
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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.
HOSES DESCRIPTION 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 compounds 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: Tube materials NBR (Nitrile Butadyene Rubber)
High resistance to mineral and biodegradable oils and fuels
CR (Chloroprene)
Mineral oils resistant
Polyammide
Resistant to wide range of fluids
PTFE
High temperature, oil, fuel and chemicals resistant
EPDM (Ethylene Propylene Diene rubbers)
Used for phosphate ester based fluids
Reinforcement The tube itself can surely not assure the resistance to the pressure 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.
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:
Rubber cover Steel braid Rubber tube
• Braided hoses • Spiral hoses
fig. 1 - Single braided hose Rubber cover 2nd braid Adhesive rubber layer 1st braid Rubber tube
fig. 2 - Double braided hose Rubber cover Body spiral carcass
Inner breaker
Adhesive rubber layer Rubber tube
fig. 3 - Spiral hose (4 spirals) Rubber cover Body spiral carcass
Inner breaker
Adhesive rubber layer Rubber tube
fig. 4 - Spiral hose (6 spirals)
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), textile 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 reinforcement (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 vulcanisation; at last the nylon tape is removed and leaves the hose bearing its imprint. Free steam vulcanisation is also used: the hose is directly vulcanised 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.
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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 pressure 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.
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 abrasion 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 particular 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 conditions, 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
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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 Goldenblast TM range is dedicated to these applications Water cleaning • industrial cleaning • paint removal Water cleaning systems are used not only in the hobby applications 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.
Hose Selection
INTRODUCTION
20
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 cover
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 market 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 spectacular 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 components 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 pressure are constructed in layers, and each layer is designed to fit a particular need in the overall performance requirement. Most hoses have at least three 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 synthetic rubber or thermoplastic like nylon or polyester. The main function of the tube is to convey the liquid, gas or a combination of the two. For this reason it must be chemically resistant to the Fluid conveyed. Always consult the Manuli’s chemical resistance information for proper selection.
reinforcement
inner tube
fig. 1 - One braid hose
Braid
fig. 2 - Two braids hose
fig. 3 - Wire spiral hose
SAE 100R4
Helix Wire
fig. 4 - Suction hose with helix wire
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 carbon steel, stainless steel of different strength and thicknesses. There are three common methods of applying the hose reinforcement. 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 prevents 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 reinforcement 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 manufacture, industry specification, etc. A common industry specification on hydraulic hose would be an ISO or SAE rating.
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HYDRAULIC HOSE INTERNATIONAL STANDARDS
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In order to have a better understanding of the selection criteria 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 characteristics for all the different categories of hoses; among others, these are the ones relevant to the scope of this manual:
*
* 100R1A, 100R1AT, 100R2A, 100R2AT 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:
Manuli Rubber Industries has a wide range of products that covers all specifications of the international standards. 23
Manuli Product Range
Wire Braid
Textile
Wire Spiral
ISO Standard
Current EN Standard
Traditional International Standard
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
Manuli Hose Line 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
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.
HOSE SELECTION CRITERIA
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Proper hose selection is critical in order to realise a safe hydraulic system. The first step in having a safe hydraulic system is selecting components that meet the needs. Compromises in hose selection may create situations of danger, as well as affect the performance and durability of the system. 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 correctly 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.
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. Hose I.D. Standard hydraulic hoses (ref. ISO 4397)
R5 and PTFE hoses
Dash No.
Inches
mm
Inches
mm
-2 -3 -4 -5 -6 -8 -10 -12 -14 -16 20 -24 -32 -36 -40 -48 -56 -64 -72
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
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 -
----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 ---------
----4.8 6.4 7.9 10.3 12.7 15.9 --22.2 28.6 34.9 46.0 --60.3 ---------
• “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). The hose size numbering system
Hose is sized on I.D.
Hydraulic Tubing is sized on O.D.
SAE 100R5 and PTFE
Tubing
25
26
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 identified 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 turbulence and excessive pressure loss (for suction lines the potential pump cavitation must be considered). Manuli reports the following maximum recommended values: Nominal diameter calculation Flow Rate 100
Velocity
75
0,1
50 40
Diameter 0,5
30
0,2
4”
DN 102
0,3
3”
DN 76
2”
DN 51
0,4 0,5
1 1,5 2 3 4 5 6 8 10
1 1,5 2 2,5 3 3,5 4 5 6 7 8 9 10 15
1 1/2” 1 1/4”
10
DN 38 DN 31,5
1”
DN 25
3/4” 5/8”
DN 19 DN 16
1/2”
DN 12,5
3/8” 5/16”
DN 10 DN 8
1/4”
DN 6,3
3/16”
20
DN 5
500 400 350 300 250 200 150 100 70 60 50 40 30
5 4
20
3 2
1
10
5 4
20 3
ft / s
m/s
0,5 0,4 0,3 0,25
gal / m
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
2
1
l / m
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 temperatures, 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 considered: • extreme cold environmental temperatures for the potential hose cracks due to bend efforts; • extreme hot ambient temperatures, in presence of irradiation 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 manufactured 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.
27
28
For example, for extended temperature range applications use Manuli EQUATOR™ hose (see the Manuli temperature range categories). Three main categories of temperature range -40 ST Standard Temperature
100 continuous
125 peaks
-40 HT High Temperature
121 continuous
135 peaks
-55 ET Extended Temperature
When selecting a replacement assembly, the same considerations must be applied: fluid temperature and ambient temperature must be carefully considered. The hose selected must be capable of withstanding the minimum and maximum temperature seen by the system. Care must be taken when routing near hot manifolds: in extreme cases, heat shield may be advisable. 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 application, 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?
135 continuous
150 peaks
• 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 substantially 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 magnitude 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. Abrasion Resistance ISO 6945 (2000 cycles, 2,5kg) grams lost
0,50 OFFERS AT LEAST 1000 TIMES HIGHER RESISTANCE THAN STANDARD
0,6 0,5
0,25 0,4 0,3
0,05
0,2
0,01 1
< 0,001
