The Influence Of The Exposure Temperature On The Working Pressure Of The Hose
The influence of the exposure temperature on the working pressure of the hose
Why is the hose called 20bar working pressure sometimes only under the working pressure of 8.4bar? Under what conditions can our hose achieve the maximum working pressure? This involves a lot of factors, such as temperature, joint, withholding etc.. Today we focus on the effect of working temperature on working pressure.
The effect of temperature rise on any hose system is significant, but it is often ignored in China. Because most of the hose's identification and brochures indicate the maximum working pressure and the maximum working temperature, there is a misunderstanding: the hose achieves the maximum pressure and the maximum working temperature at the same time. But in fact, when the hose is heated, it becomes very soft. This change will weaken the pressure capacity of the hose, and also reduce the hose holding ability of the joint, thus affecting the working pressure. So the question is, what is the relationship between the work pressure and the temperature?
Generally speaking, the working pressure of fluid connectors and hoses is set at 20 C at room temperature. If the temperature exceeds 20 C, the working pressure of hoses will decrease.
Hose type description
Steam pipe: the emphasis is on the hose that conveyed hot water and steam.
Bitumen pipe: rubber pipe for transporting high temperature oil based products such as tar, asphalt and hot oil. The working pressure is affected by the temperature of the steam pipe.
PVC tube: smooth polyvinyl chloride or ethylene tube;
Chemical pipe: the internal glue material is PTFE, UHMW, XLPE, does not include the inner tube is the type of soft rubber;
Water gas pipe: a conventional multi-function tube used to transport water and compressed air.
Soft wall tube: smooth, thick, soft, multi fingered natural rubber or food grade rubber tube;
PTFE pipe: PTFE hose, containing steel wire and bare pipe.
The problem is simple. Based on the temperature of the hose system application, the appropriate pressure drop coefficient is multiplied by the pressure level of the hose system, and the real working pressure can be obtained. Here in the United States Supflow (seyfer) CRATOS anti rolling food pipe as an example.
The anti rolling food pipe CRATOS, which has special reinforced layer material and excellent flexibility, can be recovered after accidental extrusion. It is usually used for gravity flow transportation, pressure transportation or suction operation of oil and non oil food in tanker.
Hose: 2 "CRATOS nominal working pressure is 20bar
Joint: 2 "DIN nominal pressure 25bar
Use temperature: 90 degrees centigrade
Depressurization coefficient: 0.42
The working pressure of the hose assembly: 20barX0.42 = 8.4bar
Note: the hose assembly needs to select the working pressure of the weakest part of the assembly part of the hose assembly as the working pressure of the assembly.
The production of non blue assembly was carried out in strict accordance with the ASTM D380 and NAHAD manual and tested at 20 C at normal temperature. The normal use of the customer hose assembly, transport medium at room temperature, working pressure is the same; but when the online cleaning and disinfection, customers will choose to use 90 hot water, according to the above calculation, we now know hose assembly working pressure is 8bar (no longer nominal 20bar), which is widely used in the scene. So the customer needs to pay attention to the pressure effect of the temperature change in the use and use it correctly.
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