Hose Installation Guide 软管安装指南

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Hose Installation Guide[size=14.44444465637207px]

Installation, maintenance and safety guidlines

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Flexible hose assemblies are engineered to provide maximum service life when properly installed. It is important to note that improper installation, incorrect flexing or careless handling in an application will reduce the effective service life of the hose and cause premature failure of an assembly.

The following installation and handling precautions should be observed to achieve optimum performance from your corrugated hose assemblies.

Avoid Torque	Do not twist the hose assembly during installation when aligning the bolt holes in a flange or in making up pipe threads. The utilization of swivel / lap joint flanges or pipe unions will minimize this condition. It is recommended that two spanners be used in making the union connection; For example; one to prevent the hose from twisting and the other to tighten the coupling.
In plane lateral offset installation	Prevent out-of-plane flexing in every installation as this will cause hoses to twist; however it should be noted that this can be compensated by using rotary unions. Always install the hose so that the flexing takes place in only one plane. This plane must be the plane in which the bending occurs.
Avoid over bending	The repetitive bending of a hose to a radius smaller than the radius listed in the products data sheet found on the Flextech’s website for corrugated metal hose assemblies will result in premature hose failure. Always provide sufficient length to prevent over bending and to eliminate strain on the hose and the end connections.
Avoid sharp bends	Utilize sound geometric configurations that avoid sharp bends, especially near the end fittings of the assembly is essential for good installation practices. It should be noted that failure to comply to these requirements will result in un-necessary tension being generated and premature failure will occur. This is one of the most common causes of premature hose failure which can be easily eliminated. If in doubt then please contact our sales office for advice.
Provide support	When installing the assembly in a horizontal loop, provide support for the arms to prevent the hose from sagging. The weight of hose will put un-necessary tension on the hose connection ends and will reduce the life expectancy causing premature failure.
Do not compress or extend axially	A piping system which utilizes flexible hose assemblies  to absorb movement must be properly anchored and/or guided. Always support the piping to prevent excessive weight from compressing the hose and relaxing the braid tension.

Handle with care
Avoid careless handling of the hose assembly. Always lift or carry metal hose to prevent abrasion damage particularly to braided corrugated hose.
Store all hose assemblies away from areas where they  can be subjected to spillage, corrosive fumes or sprays, weld splatter, or any other possibility which may cause damage to the hose.
If the hose’s external braid or covering becomes damaged then the hose assembly must be removed from service and tested at 1.5 times its max operating pressure to re-validate as safe for service.

Do not depressurise or expose to high temperatures
The system that the hose assembly is to be installed into shall be protected from over pressurization and from excessive temperature.
If a hose is exposed to either over pressurization or excessive temperatures outside of it’s recommended parameters then it must be removed from service and tested at 1.5 times its max operating pressure.

Do's

Dont's

Follow any printed instructions included with the hose assemblies. Follow industry–recommended practices and use care in handling and installing all hose assemblies. Always install hose assemblies so that the bend is as close to the centre of the connector as possible. Observe the minimum bend radius as specified by the manufacturer. Trial-fit threaded connections by hand, unmake and then make permanent. Use a hose assembly of proper length to suit the installation. Only tighten up on the fitting hex flats as provided. Install vents and draws to permit the hose to be removed. Install the proper length hose assembly to allow a 2" straight run of hose at each end fitting. Use correct sized spanners on both mating hexes to avoid twisting the hose during installation. Visually inspect hose on a regular basis. Test hose at 1.5 times its maximum operating pressure annually. Check for leaks before covering the installation. Install in such a manner that the hose assembly can be removed easily when required. Make sure the pressure rating of a hose assembly  is not exceeded.

Apply a spanner / grips to a hose, collar or assembly. Twist hose assemblies during installation or when aligning the bolt holes in a flange or when making up pipe threads. "Pre–flex" a hose assembly to loosen it up as over–bending could cause damage and result in leakage. Over–bend a hose assembly. A 45°–90° bend should be sufficient to install any flexible connector. Install a hose assembly with the bend next to the end fittings. This could cause damage and result in leakage. Lay the hose assembly on rocks or objects which could puncture the hose and cause leakage. Attempt to stretch or compress a hose assembly to fit an installation. Restrict flexibility by allowing the hose assembly to come into contact with other components or equipment during installation.

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Maintenance and Replacement Guidelines

Even with proper selection and installation, hose life may be significantly reduced if a continuous maintenance program is not in place. The frequency of inspection and replacement of assembly components should be determined by the system’s operating environment, the potential risk from a hose failure and any past experience of hose failures in the application or in similar applications.

Visual Inspection:
Any of the following conditions require immediate shut down and replacement of the hose assembly:

• Fitting slippage on hose.
• Damaged, cracked or charred hose.
• Damaged, frayed outer braids or covers.
• Cracked, damage or badly corroded fittings.
• Leaks at fitting or in hose.
• Kinked, crushed, flattened or twisted hoses.
• Blistered, soft, degraded or loose covers.
  

The following items must be tightened, repaired, corrected or replaced as required:

• Leaking fittings.
• Worn clamps, guards or shields.
• System fluid level, fluid type and any air entrapment.
  

Function Test:
Operate the system at maximum operating pressure and check for possible malfunctions and leaks.
Personnel must avoid potentially hazardous areas while testing the system.

Replacement Intervals:
Hose assemblies and seals used on Hose Fittings and adapters will eventually age, harden, wear and deteriorate under thermal cycling and compression set.
Hose assemblies and all seals should be inspected and replaced at specific replacement intervals based on previous service life, industry recommendations, or when failures could result in unacceptable downtime, damage or injury risk.

Seals used in fittings and adapters:
All seals, such as Dowty and Elastomeric, will eventually age, harden, wear and deteriorate under thermal cycling and compression set. These seals should be inspected regularly and replaced when needed.

Hose inspection and failure
From time to time hose assemblies will fail if they are not replaced at appropriate time intervals.
Usually these failures are the result of some form of misapplication, abuse, wear or failure to perform proper maintenance. When hoses fail, the high pressure fluids can escape in a stream which may or may not be visible to the user. Under no circumstances should the user attempt to locate the leak by feeling with their hands or any part of the body. High pressure fluids can penetrate the skin and cause severe tissue damage. If hose failure occurs shut down the equipment immediately and leave until pressure has been completely released from the hose assembly. Simply shutting down the system may not eliminate the pressure in the hose assembly.
It may take some time for the pressure to reduce to a safe level for inspection. The hose assembly and equipment then can be checked and faulty components replaced.

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Considerations

Provided the correct and full conditions of use have been given at the time of order placement and the assembly is subsequently installed within its design parameters, the flexible hose assembly (FHA) or pressure equipment can give many years of satisfactory service life. To help maximise this service life the following guidelines should be followed.

1. Integrity
The integrity of FHAs is very dependant on the correct selection of hose product and adherence to the installation procedures. Flextech suggest that all personnel required to install, inspect and maintain FHAs should be formally authorised, and fully conversant with the appropriate installation, test and maintenance procedures, failure criteria etc.

2. Safety Considerations
• FHAs should not be used where it is safer to install permanent pipe work.
• Design – FHA’s suitability with systems piping and equipment.
• Application – suitability of the FHA in relation to media, pressures, temperature and when used in suction applications, ability to withstand vacuum.
• External Environment - FHAs should only be used for duties for which they are approved.
• Installation - FHA’s should be adequately supported and installed to the manufacturer guidelines, as applicable and  consistent with the best practice principles contained within this guidance document.
• Length – FHA’s should be kept to a minimum, consistent with flexibility and required function.
• Electricity – dangers of static electricity in the application and effects on all components associated with FHA’s continuity requirements.

3. Vibration/Movement
FHAs may eliminate the transmission of vibration or movement in a specific application. FHAs will only efficiently eliminate the transmission of vibration, movement or noise if the adjacent pipe work is properly anchored on the downstream side of the hose. In the worst cases, failure to ensure this can lead to uncontrolled movement of the FHAs and premature failure.

4. Misalignment
FHAs should not be used as a remedy for poor design or installation, eg to correct misalignment of rigid components.

5. Degradation
Degradation of FHAs can be accelerated due to heat, environmental conditions or contamination of the outer coverings and braids due to chemicals, ultraviolet light, ozone, salt, water etc. It should be noted that the fluid composition could change over the expected lifecycle.
Note: Heat tracing and insulation can considerably accelerate any corrosion mechanisms.

6. Storage
All FHAs should be stored in clean, dry conditions and hoses of rubber and composite construction should be kept in a cool atmosphere protected from direct sunlight. Some hose linings, if not protected prior to putting into service, have a finite shelf-life.

7. Cleaning and Flushing
All components used in a system that includes a FHA should be cleaned and flushed prior to use, to prevent debris being carried, damaging the liner of the hose.

8. Operations, Maintenance, Inspection & Testing
Users should ensure that all FHAs are subject to a periodic inspection routine. Only authorised, competent personnel should be permitted to install, inspect and maintain flexible hose lines. Visual inspection of the hose body for cuts, kinks, bulges, signs of abrasion, corrosion products etc. Particular attention should be focused close to the end coupling for signs of over-bending or leakage.

9. Changing Conditions
The user should be aware of changing conditions, which may move the FHAs away from the original design intent. Changes can include, but are not limited to: pressure, temperature, flow, media etc.

10. User’s/Purchaser’s Responsibility to Define Requirements
The user or purchaser of any FHA should always ensure that the following information is provided as applicable: Always consider and properly define the application of the FHA by referring to: STAMPED: Size, Temperature, Application, Media, Pressure, Ends,  In addition consider static or dynamic use of hose and the working environment.

11. Legal Requirements
It is a legal requirement under health and safety law, power regulations and the Pressure Equipment Directive 97/23/EC that those responsible for work activities ensure that hazards are adequately identified risks are adequately assessed and that suitable control measures are put into place.

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