In addition to continuous blowdown service, the Hancock high pressure drop valve is also used on feedwater bypass relief, sampling systems, drains and other services where erosion is extremely severe.

除了连续排污服务，高压降汉考克阀门也用在给水旁路救济，取样系统，排水渠及其他服务的地方水土流失极为严重。

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Several companies provide services, and you can get a sampling of them at booking site FerrySavers.com.

BBC: Navigating the London 2012 exodus