适用范围：范围:本标准规定了止回阀的基本要求、能效等级及试验方法。 本标准适用于以水为介质的公称尺寸DN50～DN300的旋启式止回阀、导流式速闭止回阀、多功能水泵控制阀、缓闭止回阀。其他种类止回阀可参照执行; 主要技术内容:止回阀能效等级分为3级，其中1级能效最高，2级为节能评价值，3级为基本能效值。表1 止回阀的能效等级（规定流速3.0m/s下止回阀能效值（kPa））类型                       公称通径  1级          2级         3级旋启式止回阀        DN5014.88 17.51 19.26DN6512.41 14.60 16.06DN8010.91 12.83 14.11DN1009.43 11.09 12.20DN1259.09 10.69 11.76DN1507.50 8.82 9.70DN2006.49 7.63 8.39DN2505.91 6.95 7.65DN3005.23 6.15 6.77导流式速闭止回阀DN5034.6438.4942.34DN6526.2429.1532.07DN8024.4227.1329.84DN10017.5119.4521.40DN12511.8213.1314.44DN15010.6311.8112.99DN2007.077.858.64DN2506.877.638.39DN3005.616.236.85多功能水泵控制阀DN5085.9195.46105.01DN6582.4991.66100.83DN8070.4678.2986.12DN10068.8176.4684.11DN12560.6367.3774.11DN15055.7761.9768.17DN20051.5657.2963.02DN25041.9146.5751.23DN30039.5043.8948.28缓闭止回阀        DN5072.38 80.42 88.46DN6565.89 73.21 80.53DN8059.39 65.99 72.59DN10057.47 63.86 70.25DN12