通径：DN65 - DN250
Sizes: 2¹/₂" – 10" (65 to 250 mm)

　　系列757DCDA，757NDCDA双止回阀检测器总成用于防止非健康危害、不能采用，但是无毒的污染物回流进入饮用水供应系统中。系列757DCDA，757NDCDA可以安装在持续压力应用中，并且可能与反压力和反虹吸相关。系列757DCDA，757NDCDA主要用在有必要监控未经许可用水的消防喷淋系统上。
　　Series 757DCDA, 757NDCDA Double Check Detector Assemblies are used to prevent backflow of non-health hazard pollutants that are objectionable but not toxic, from entering the potable water supply system. The 757DCDA, 757NDCDA may be installed under continuous pressure service and may be subjected to backpressure and backsiphonage. Series 757DCDA, 757NDCDA is used primarily on fire line sprinkler systems when it is necessary to monitor unauthorized use of water.

性能
Features

• 结构非常紧凑
  Extremely compact design
• 比传统设计轻70%
  70% Lighter than traditional designs
• 304（目录40）不锈钢外壳和套筒
  304 (Schedule 40) Stainless steel housing & sleeve
• 槽状连接件，允许整体管道调整
  Groove fittings allow integral pipeline adjustment
• 专利三连接止回阀提供最低的压力损失
  Patented tri-link check provides lowest pressure loss
• 特别容易维修
  Unmatched ease of serviceability
• 可提供槽状连接蝶阀为关闭阀
  Available with grooved butterfly valve shutoffs
• 可提供水平，垂直或N形安装方式
  Available for horizontal, vertical or N pattern installations
• 可更换止回阀阀瓣橡胶
  Replaceable check disc rubber

规格说明
Specifications

　　这种双止回阀检测器总成应该由在一个外壳内两个独立的三连接止回阀模块，套筒进入端口，四个测试旋塞和两个不透水关闭阀构成。三连接止回阀应该是可拆卸和可维修的，不需要采用特殊工具。外壳应该由304目录40不锈钢管结构，配置槽状端口连接。三连接止回阀应该配置双向合成橡胶阀瓣，运行时对于由于反压力或发虹吸产生的反向流动具有不透水的密封性。旁路总成应该由一个能够记录加仑或立方制式的水表，双止回阀回流总成构成，还需要配置测试旋塞。这种总成应该是美国瓦茨调节阀公司系列757DCDA，757NDCDA。
　　The Double Check Detector Assembly shall consist of two independent tri-link check modules within a single housing, sleeve access port, four test cocks and two drip tight shutoff valves. Tri-link checks shall be removable and serviceable, without the use of special tools. The housing shall be constructed of 304 Schedule 40 stainless steel pipe with groove end connections. Tri-link checks shall have reversible elastomer discs and in operation shall produce drip tight closure against reverse flow caused by backpressure or backsiphonage. The bypass assembly shall consist of a meter, which registers in either gallon or cubic measurement, a double check backflow assembly and required test cocks. Assembly shall be a Watts Regulator
Company Series 757DCDA, 757NDCDA.

757DCDAOSY

757DCDABFG

757NDCDAOSY