两个止 回阀和安全阀的阀座和阀座阀 瓣应该是可更换的，更换过程不需要特殊工具。

Seats and seat discs shall be replaceable in both check valves and the relief valve without the use of special tools.

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两个止 回阀和安全阀的阀座和阀座阀 瓣应该是可更换的，更换过程不需要特殊工具。

Seats and seat discs shall be replaceable in both check valves and the relief valve without the use of special tools.

youdao