When new pipe is connected to old rusty pipe, generally, the new pipe is anodic to the old pipe.

当新管子和生锈旧管子相连时，新管子相对于旧管子常为阳极。

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If the drill pipe threads become rusty, rust will have to be cleaned.

如果钻杆丝扣生锈，必须清除掉。

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At the end of the pump valves, cast iron pipe and other items to be rusty rust, and then coated with butter, dry place on the preservation, re-use for winter and spring.

水泵的底阀、弯管等铸铁件，生了锈的要除锈，然后再涂上黄油，放在干燥处保存，以备冬春再用。

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At the end of the pump valves, cast iron pipe and other items to be rusty rust, and then coated with butter, dry place on the preservation, re-use for winter and spring.

水泵的底阀、弯管等铸铁件，生了锈的要除锈，然后再涂上黄油，放在干燥处保存，以备冬春再用。

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