There are valve dither and valve set point circuit to improve the performance of the system.

为改善伺服阀的特性，在系统各通道的伺服输出电路中增加了可程控的阀偏置和阀颤振电路。

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Each hot water space heating boiler shall be equipped with a pressure relief valve set to relieve below the maximum boiler working pressure.

每个热水供暖锅炉都必须配置压力安全阀，其设置的泄压压力必须小于锅炉的最大工作压力。

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The control execution unit set comprises a controllable heating valve set and a controllable refrigerating valve set and can realize controllable operation of heating and refrigerating;

所述控制执行单元组包括可控加热阀门组和可控制冷阀门组，可实现制冷和加热的可控运行；

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In writing the law, Congress included a safety valve and told the EPA to set the mandate to meet "the projected volume available" in the event of a shortfall.

WSJ: Review & Outlook: Zero Dark Ethanol

In order to stop flood waters overwhelming central London and to save the massive expense of building fresh flood walls and defences, some land could be set aside to act as a safety valve, catching flood waters and storing them until the danger has passed.

BBC: London's drowning

Nothing's set in stone, of course, and Valve's still very much in the exploratory phase of its Steambox push.

ENGADGET