Extremely cold environments with conditions such as snow, ice, and high wind speeds are a challenge for all rubber hydraulic hoses.
Frequently, hoses must withstand temperature ranges below -57 °C which influences the rubber compounds used on the inner tube and the hose cover. What does this mean for your equipment?
What are the consequences of changed material characteristics in rubber hoses exposed to extreme cold?
When the rubber is permanently cooled, the material characteristics and the bending behaviour will change even if the product has been developed for such temperature limits. Elastomers are used at the inner tube and the hose cover. When cooled to permanent low temperatures, hoses may no longer behave with their normal characteristics and become hard, stiff and inelastic. They can even decompose or work at reduced performance under continuous thermal loads. The material parameters change under the influence of heat and cold. If you cool down to lower temperatures, rubber becomes hard, tough and leathery.
Engineers describe this process with thermal changes that affect the molecular behaviour and the microstructure becomes crystalline. The result is that the rubber compounds become brittle, but in principle, they remain deformable. The heat builds up in heat or mechanical energy. At -40 ° C (depending on rubber compound and hardness) the so-called glass point is reached; the rubber is hard. Crystallization of the elastomer at low temperatures may cause cracking. However, this depends strongly on the type of load in the low-temperature range, more critical here are shock loads. We strongly recommend a regular visual inspection of the rubber for cracks, which can reduce its service life under unfavourable conditions and failure and leakage can occur when the temperature exceeds the rubber compounds acceptable range.
How do the right ingredients influence the performance of rubber hoses in extreme cold?
Hose manufacturers, such as Parker, are continuously putting their designs to the test. With the latest in technology, our state-of-the-art materials development and performance test labs are capable of determining baseline engineering and design properties to ensure that hoses meet application requirements. The cold-flexibility test is one of those tests required to meet specific specifications such as ISO 10619-2. An advantage to Parker's manufacturing process is the use of in-house compounds. This advantage opens new opportunities for the ideal compounds mixture of hoses such as Parker's SX35LT and SX42LT, which are multispiral hoses with four or six spiral high tensile steel wires for high-pressure applications of 35,0 Mpa (5000 psi) and 42,0 Mpa (6000 psi) for extremely cold environments. These hoses are developed for extreme cold and demanding low-temperature applications.
Parker also offers braided hoses with a synthetic rubber inner tube and as well a No-Skive thin synthetic rubber cover construction for mobile applications in low-temperature environments such as forestry machines or refrigerated warehouses (461LT) or a 3-wire braid low-temperature compact hose with 4SP working pressures (371LT). These two hose types are not only cold resistance up to -50 °C but also characterized for an excellent ozone resistance. General typical applications are heavy construction equipment, side booms, mining and/or mobile equipment, arctic oil fields, materials handling in low-temperature conditions, snow grooming equipment and any cold storage applications.
Hoses fail when you least expect it; What does this mean for you when working in remote places?
If your equipment relies on hydraulic systems, you know, it is not “IF” but “WHEN” a hydraulic hose fails, the race against downtime begins. The longer your equipment is down, the greater the loss and cost. Hydraulic system failures cause 35 to 65 percent of all mobile equipment downtimes – a great part due to relatively simple and cheap hydraulic hoses.
Ask yourself the following questions:
- Do you lose money when your equipment is down?
- Do you have to travel a far distance to reach the nearest hose workshop?
- Do you have to wait a considerable time for a replacement hose assembly?
- Do you have to replace hose assemblies often?
- Do you have to replace hoses at night or even on weekends?
If YES is the answer to your questions, then the Parker Parkrimp No-Skive Self-Assembly system might be a problem solver for you.
Learn more about how to make your own assemblies using Parkrimp® No-Skive hose crimpers.
International companies with substantial expertise, such as Parker, have a global presence for the leading companies of the mobile market and can offer the right hose for each mobile application and on top, you can choose the way of product supply which best answers your individual manufacturing philosophy. The delivery options include complete hose assemblies, hose/tube assemblies, single hose and fittings and hose crimpers and tooling for the Parkimp No-Skive self- assembling.
This blog was contributed to by Conny Stöhr, marketing services manager, Hose Products Division Europe.
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