Do outdoor compressed air pipes need expansion joints?
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There are 2 gas pipelines for normal-temperature use, installed side by side in the pipe tray, with diameters of DN300 and DN65. From the station building to the workshop, the outdoor section is about 80 meters long; are expansion joints and fixing brackets necessary? What needs to be paid attention to?
Recently, I saw the compressed air pipelines in the plant of a certain company; they were at room temperature, with a length of just over 100 meters and less than 200 meters, and the largest diameter was DN400. There were several bellows expansion joints and fixed supports installed along the pipelines, but it was found that the limiting rod of one of the bellows expansion joints had broken. It is said the reason is that no fixing bracket was provided at the free end of the compensator. I have been working on compressed air pipelines for some time now, and I think that such pipelines at normal temperatures should be fine even without fixed supports or compensators. Now that a compensator is in place, even without fixed brackets, the tie rods should not break!! I hope the experts here can give me some advice~~
If it is a pipeline at room temperature and its length isn’t too great, only 80 meters. In most cases, expansion joints are not necessary; a few bends in the pipeline are sufficient to absorb thermal displacement. Therefore, the use of expansion joints is not recommended.
Pipes with such a small diameter and short length are completely unnecessary; the medium flowing through them is at room temperature, and the only factor that can cause temperature changes is the ambient temperature, and these changes are not significant. In the example you gave, with a large diameter, it may be necessary to add compensators; however, it’s fine to include some elbows to accommodate changes in direction, and stress calculations are required for this.
It shouldn’t be necessary; it’s at room temperature, the pipeline is short, and the diameter is small
First, the type of pipeline compensator must be determined, with the specific model to be chosen based on actual requirements. It only mentions that the temperature is constant; is the pressure also constant? ? Since all the limit bolts have been pulled apart, it indicates that the setting of this compensator has exceeded its operational limits. Another key aspect is how to choose pipe compensators; generally, the most reliable approach is to install horizontal \"U\"-shaped bends at regular intervals along the straight pipes, as this provides the best compensation effect for pipes under high pressure with significant pressure fluctuations. For large-diameter low-pressure pipelines, corrugated pipe compensators must be used. For high-pressure pipes with limited space in special locations, there are also specialized compensators. (For reference)
It shouldn’t be necessary; it’s at room temperature, the pipes are short, and the pipe diameter is small. If the pipeline is long and there are not many elbows, adding them can be considered.
It should not be necessary; for pipes at room temperature with a small temperature difference, the amount of expansion or natural compensation can be calculated based on the direction in which the pipes run