The design pressure of the ventilation pipe wall bushing is greater than 1.6MPa for the casing with gas medium, 2.5MPa for the casing with liquid medium, and the casing with flammable, explosive or toxic medium above medium hazard. The ventilation pipe wall bushing shall perform dye penetrant inspection or radiographic inspection on the inner surface of the outer surface of the weld that can be used for flaw detection. The wall bushing of ventilation pipe shall be used for the casing of gas medium with design pressure greater than 0.1MPa but less than or equal to 1.6MPa, and the wall bushing of ventilation pipe with design pressure greater than 0.1MPa but less than or equal to 2.5MPa and used for liquid medium.

對每批同材料同厚度的縱焊縫應(yīng)進行少10%的抽樣著色探傷或射線探傷，同時，抽樣應(yīng)不少于一條焊縫。著色傷只適于管坯厚度不大于2mm的單道焊縫。驗收標準為：不允許有裂紋等線狀顯示、四個或四個以上邊距小于1.5mm的成行密集圓形顯示、任一150mm焊縫長度內(nèi)五個或五個以上直徑大于1/2管坯厚度的隨機分散的圓形顯示。用于通風管道穿墻套管通常有兩種，一種是機械加工成形的，另一種是通風管道穿墻套管。

For each batch of longitudinal welds with the same material and thickness, at least 10% of the samples shall be subject to dye penetrant inspection or radiographic inspection, and at least one weld shall be sampled. The stain damage is only applicable to the single weld with the thickness of tube blank not more than 2mm. The acceptance criteria are: no linear indications such as cracks, four or more rows of dense circular indications with edge distance less than 1.5mm, five or more random scattered circular indications with diameter greater than 1/2 of the tube blank thickness within any 150mm weld length. There are usually two types of wall bushing used for ventilation duct, one is machined and the other is wall bushing for ventilation duct.

通風管道穿墻套管總體高度比較低，但由于其制造方法和內(nèi)在結(jié)構(gòu)上的缺陷，使用壽命可能是有限的；機械加工成形的通風管道穿墻套管相比總體高度較高，但可靠性更高， 壽命更長。管網(wǎng)系統(tǒng)連接用的大型波紋套管，要求承壓4MPa，耐溫400℃，且有一定的耐腐蝕穩(wěn)定性。通風管道穿墻套管的溫度適應(yīng)能力取決于所采用彈性材料的耐溫性能。

The overall height of the wall bushing of the ventilation pipe is relatively low, but its service life may be limited due to its manufacturing method and inherent structural defects; Compared with the overall height, the machined wall bushing of the ventilation pipe has higher reliability and longer service life. The large corrugated casing used for the connection of pipe network system is required to have a pressure of 4MPa, a temperature resistance of 400 ℃, and a certain corrosion resistance stability. The temperature adaptability of the wall bushing of the ventilation pipe depends on the temperature resistance of the elastic material used.

因此根據(jù)通風管道穿墻套管的使用溫度范圍，選用合適溫度性能參數(shù)的彈性材料，才能加工制造出合格的通風管道穿墻套管類組件。由于工作狀態(tài)的不同，元件損壞或失效的模式也不同。儀表彈性元件工作在彈性范圍內(nèi)，基本上處于靜態(tài)工作狀態(tài)，使用壽命很長，一般達到數(shù)萬次到數(shù)十萬次。

Therefore, according to the use temperature range of the wall bushing of the ventilation pipe, select the elastic materials with appropriate temperature performance parameters to process and manufacture qualified components of the wall bushing of the ventilation pipe. Due to different working conditions, the mode of component damage or failure is different. The elastic element of the instrument works within the elastic range, and is basically in a static state. It has a long service life, usually tens of thousands to hundreds of thousands of times.