Volume compensation device for expansion joint of double-layer corrugated pipe

Abstract

The invention belongs to the technical field of petrochemical industries, relates to a volume compensation device for an expansion joint of a double-layer corrugated pipe, and mainly comprises a volume compensation corrugated pipe (15) and driving springs (16). The upper end of the volume compensation corrugated pipe (15) is connected with a vacuum pressure gauge (14) through a sealing plate (13), and the lower end of the volume compensation corrugated pipe (15) is communicated with interlamination of straight pipe sections of the double-layer corrugated pipe through an end pipe (1). Two driving springs (16) for driving the volume compensation corrugated pipe to achieve tension or compression to provide volume compensation are respectively arranged on two sides of the volume compensation corrugated pipe, and two ends of the driving springs (16) are respectively fixed on the end pipe (1) and the sealing plate (13). The volume compensation device for the expansion joint of the double-layer corrugated pipe can provide compensation volume larger than the volume of the interlamination of the double-layer corrugated pipe, compensates changes of vacuum degree caused by leakage of a vacuum system, avoids wrong judgment caused by the changes of vacuum pressure of a detection device, is matched with a monitoring device for use, and enables the monitoring device to be reliable.

Description

technical field [0001] The invention belongs to the technical field of petrochemical industry, and mainly relates to a volume compensating device for expansion joints of double-layer corrugated pipes. Background technique [0002] For the application environment with strict requirements for bellows failure control, the bellows is usually designed as a double-layer structure, and each layer can withstand the working conditions (temperature, pressure) independently. When one layer fails, the other layer can still work normally. In order to detect the failure of the bellows in time, it is necessary to set up a monitoring device to determine whether the bellows has failed. The vacuum method is one of the methods to determine whether the bellows has failed. To monitor the change of the vacuum degree between the bellows layers. According to the ideal gas state equation, PV=nRT (P is the gas pressure, V is the gas volume, n is the amount of gas substance, R is the ideal gas c...

AI Technical Summary

Problems solved by technology

After the double-layer corrugated pipe is evacuated, the two layers are closely bonded, the volume between the two layers is very small, and the interlayer pressure is close to 0. When the vacuum system leaks, the gas pressure entering the interlayer is P 0 , if the volume of gas entering the interlayer is very small as V 0 , since the interlayer volume is very small after vacuuming, the volume V of the interlayer gas balance of the double-layer bellows 1 ≈V 0 , so the vacuum system pressure P after gas balance 1 =P 0 V 0 / V 1 ≈P 0 , causing the pressure value displayed by the vacuum pressure gauge on the monitoring device to change greatly, which makes it very sensitive to the leakage of the vacuum system, and it is easy to cause misjudgment on whether the double-layer bellows leaks

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