一、结构及用途 structure and purpose
该阀用于水泵出口控制水泵的实际工作扬程 ,以限制水泵的工作流量,限制水泵电机负载,使水泵在较高效率状态下工作,防止水泵电机在低扬程、大流量、低效率时发生过载现象，防止超额定电流烧坏水泵电机现象发生，同时起到一定节能效果。安装、维护、调试、检查方便，使用寿命长，同时具有缓闭清声止回阀功能。
This valve is used at a water pump's outlet to control the real working head of the pump so as to limit the working flow and the motor's load of it，make the pump working in a higher efficiency, prevent the motor from being overloaded in case if a low head，a big flow or a low efficiency and from being burnt due to an extra-rated cu r rent，with a certain energy saving effect Easy installation，maintenance，adjustment and check，long duration and of the function to be a slowly closed silencing check valve.
四、主要外形及连接尺寸 Schematic diagram of installation
| 公称通径 DN(mm) | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 125 | 150 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 600 | 700 | 800 |
| L | 180 | 180 | 180 | 203 | 203 | 216 | 241 | 292 | 330 | 356 | 495 | 622 | 698 | 787 | 914 | 978 | 978 | 1295 | 1448 | 1956 |
| PN10 | D | 105 | 115 | 135 | 145 | 160 | 180 | 195 | 215 | 245 | 280 | 335 | 390 | 440 | 500 | 565 | 615 | 670 | 780 | 895 | 1010 |
| D1 | 75 | 85 | 100 | 110 | 125 | 145 | 160 | 180 | 210 | 240 | 295 | 350 | 400 | 460 | 515 | 565 | 620 | 725 | 840 | 950 |
| PN16 | D | 105 | 115 | 135 | 145 | 160 | 180 | 195 | 215 | 245 | 280 | 335 | 405 | 460 | 520 | 580 | 640 | 705 | 840 | 910 | 1020 |
| D1 | 75 | 85 | 100 | 110 | 125 | 145 | 160 | 180 | 210 | 240 | 295 | 355 | 410 | 470 | 525 | 585 | 650 | 770 | 840 | 950 |
| PN25 | D | 105 | 110 | 135 | 145 | 160 | 180 | 195 | 230 | 270 | 300 | 360 | 425 | 485 | 550 | 610 | 660 | 730 | 840 | 955 | 1070 |
| D1 | 75 | 85 | 100 | 110 | 125 | 145 | 160 | 190 | 220 | 250 | 310 | 370 | 480 | 490 | 550 | 600 | 660 | 770 | 875 | 990 |
| H | 172 | 172 | 172 | 265 | 265 | 310 | 350 | 460 | 520 | 570 | 695 | 780 | 905 | 1025 | 1080 | 1030 | 1135 | 1270 | 1460 | 1640 |
| H1 | 106 | 106 | 106 | 210 | 210 | 215 | 245 | 305 | 365 | 415 | 510 | 560 | 658 | 696 | 735 | 610 | 665 | 725 | 865 | 925 |
注：安装示意图中弹性座封闸阀或蝶阀任选，建议≥ DN350选蝶阀。
