Proper Hose Selection using STAMPED-Hydraulic hoses and fittings UAE.
Here are seven steps represented by the acronym STAMPED to determine and select the right hose and connections for the hydraulic system or application.
Size – Use the proper hose size both inside diameter and outer diameter that match exactly to the original hose, use a precision engineered calliper to check and mathc sizes. Outer Diameter, is especially important when hose support clamps are being used or when hoses are routed through bulkheads. The hose should be the exact length as the one being replaced. Longer than original size hose may be pinched or even severed by moving components whereas cutting it too short may cause the hose to be stretched and contracted greatly reducing the service life of the hose.
When replacing a hose assembly, always cut the new hose the same length as the one being removed. Moving components of the equipment may pinch or even sever too long a hose. If the replacement hose is too short, pressure may cause the hose to contract and be stretched, leading to reduced service life.
Temperature – Based on Fluid temperature they are designed for, all hoses are rated with a maximum working temperature between All hoses are rated with a maximum working temperature ranging from 90°C to 150° C. Continuous exposure to higher than rated temperatures will lead to reduced flexibility of hoses and eventual failure. Use of the right hydraulic oil with the correct viscosity can is also a very important consideration and hence following the hose manufacturers written recommendation is imperative.
Exceeding the recommended temperatures can affect hose life negatively by as much as 80%. Acceptable temperature range may vary from -55° F to 205° C. Other than atmospheric temperatures, hoses exposed to heat sources in the work environment also becomes a deciding factor. Exposure to high external and internal temperatures concurrently, will reduce the hose service life considerably, hence insulating sleeves must be considered to protect the hoses from extreme heat from hot equipment parts and other such sources. Additional barriers may also be required to protect the hydraulic fluid from exposure to high temperatures.
Application – Care should be taken to mmed the bend radius requirements of the hose. Is the radius smaller than the recommended minimum value? If so, this will impact the hose reinforcement adversely and reduce the life of the hose. Wherever possible, aligning high pressure hydraulic hoses in line with machine contours helps reducing the line lengths and minimizes the requirement for flow restricting bends. This protects the hydraulic lines from external abrasions and servicing of the hose is also easier this way.
Materials – An obvious mandatory requirement should be to refer to the compatibility chart to check that the fluid used in the system and the hose material is compatible. Higher temperatures, contamination of fluid and concentration of the fluid will impact chemical compatibility. Though most hydraulic hoses are compatible with petroleum based oils, the new range of bio-degradeable or so called green fluids may present a problem for some hoses.
Pressure capabilities – The working pressure of the hose chosen for a particular hydraulic system, must always be equal to or greater than the maximum system pressure, including pressure surges. Pressure surges greater than the published working pressure will shorten the hose life significantly.
Ends– The end fittings are an integral part of the assembly. Determine the style thread necessary to connect the hose to the equipment. Find out the ideal orientation 45 or 90 degree fittings or straight in-line? Also, make sure that the correct compatible metal type is used for the media that is being transported.
Delivery-This really is about testing, packaging and delivery requirements. Does your hose need to be pressure tested? Do you want to specify a specific packaging to ensure the hose assembly arrives to your door in the right condition? and How soon do you need your hose assembly. All these factors relate to delivery of the hose
Other considerations –The mechanical interface between the hose and the coupling should be compatible so that the connection of the components is free of leaks, whether it is a permanent type used primarily by equipment manufacturers or the field attachable types. In both the cases, the end fittings are typically not suitable for reuse, as the threads distort during the primary attachment.
Mostly, the only difference between an SAE grade coupling and a non SAE coupling are the thread configuration and the seat angle of the seal. International threads ends can be metric i.e. in mm or BSP (British Standard Pipe) threads in inches. The country of origin may provide an indication as to what type of thread is used, for instance, DIN (Deutsche Industrial Norme) fittings originated in Germany and are now found all over Europe, whereas BSP threads are found on British Equipment. Japanese Komatsu machinery uses the metric (mm) Komatsu fittings some other Japanese equipment uses JIS (Japanese Industrial Standard) threads or even BSP with either tapered or straight threads. So to identify end fittings correctly, check
- Type of seat – Regular (JIS & Komatsu), inverted (BSP; DIN), or flat (flat face, flanges etc.)
- Seat angle -30° (JIS,BSP, DIN and Komatsu) or 12° (DIN, and
- Type of threads-metric (DIN or Komatsu), BSP (BSPP, BSPT or JIS) or tapered (BSPT or JIS tapered)
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