steam-cylinder upper cover

例句：

1. 1.The steam-cylinder upper cover is essential for maintaining the proper temperature of the water in the boiler.
   蒸汽发生器上部盖对于保持锅炉中水的温度至关重要。
2. 2.The engineer replaced the steam-cylinder upper cover with a new one to prevent any leakage.
   工程师用一个新的蒸汽发生器上部盖替换了旧的，以防止任何泄漏。
3. 3. During maintenance, the technician carefully inspected the steam-cylinder upper cover to ensure it was functioning properly.
   在维护期间，技术人员仔细检查蒸汽发生器上部盖以确保其正常工作。