止回阀是能自动阻止流体倒流的阀门。止回阀的阀瓣在流体压力作用下开启，流体从进口侧流向出口侧。当进口侧压力低于出口侧时，阀瓣在流体压差、本身重力等因素 作用下自动关闭以防止流体倒流。
止回阀一般分为升降式、旋启式等几种类型。
升降式止回阀的结构一般与截止阀相似，其阀瓣沿着通道中心线作升降运动，动作可靠，但流体阻力较大，适用于较小口径的场合。升降式止回阀可分为直通式和立式两种。直通式升降式止回阀一般只能安 装在水平管路，而立式升降止回阀一般应安 装在垂直管路。
旋启式止回阀的阀瓣绕转轴作旋转运动。其流体阻力一般小于升降式止回阀，它适用于较大口径的场合。旋启式止回阀根据阀瓣的数目可分为单瓣旋启式、双瓣旋启式及多瓣旋启式三种。单瓣旋启式止回阀一般适用于中等口径的场合。大口径管路选用单瓣旋启式止回阀时，为减少水锤压力，最好采用能减小水锤压力的缓闭止回阀。双瓣旋启式止回阀适用于大中口径管路。对夹双瓣旋启式止回阀结构小、重量轻，是一种发展较快的止回阀；多瓣旋启式止回阀适用于大口径管道路。
主要零件材料及性能规范
主 要 零 部 件 |
阀体、阀盖、摇杆 |
wcb |
cf8 |
cf8m |
wc6、wc9 |
阀瓣 |
wcb堆cr13或硬质合金 |
cf8堆硬质合金 |
cf8m堆硬质合金 |
wc6、wc9堆硬质合金 |
|
阀座 |
25堆cr13或硬质合金 |
304堆硬质合金 |
316堆硬质合金 |
20cr1mov堆硬质合金 |
|
垫片 |
软铁、xb450 |
聚四氟乙烯 |
聚四氟乙烯 |
不锈钢+耐酸 石棉缠绕垫 |
|
螺栓 |
35crmoa |
35crmoa |
35crmoa |
25cr1mo1v |
|
螺母 |
45 |
45 |
45 |
35crmoa |
|
主要参数 |
适用介质 |
油品、水、蒸汽 |
硝酸 类 |
醋酸 类 |
油品、水、蒸汽 |
适用温度 ℃ |
≤425 |
≤200 |
≤200 |
≤550 |
型号 |
公称 通径 nps(in) |
压力级 class |
主要结构尺寸(mm) |
阀体 材料 |
性能规范 |
|||||
d |
d1 |
l |
l1 |
h |
适用温度(℃) |
适用介质 |
||||
sfh-64c150c |
2" |
150 |
|
|
203 |
|
170 |
wcb |
≤425 |
水、油品、蒸气等 |
" |
3" |
" |
|
|
241 |
|
185 |
" |
" |
" |
" |
4" |
" |
|
|
292 |
|
215 |
" |
" |
" |
" |
6" |
" |
|
|
356 |
|
260 |
" |
" |
" |
" |
8" |
" |
|
|
495 |
|
300 |
" |
" |
" |
" |
10" |
" |
|
|
622 |
|
350 |
" |
" |
" |
" |
12" |
" |
|
|
699 |
|
400 |
" |
" |
" |
" |
14" |
" |
|
|
787 |
|
450 |
" |
" |
" |
" |
16" |
" |
|
|
864 |
|
480 |
" |
" |
" |
" |
18" |
" |
|
|
978 |
|
540 |
" |
" |
" |
" |
20" |
" |
|
|
978 |
|
600 |
" |
" |
" |
" |
24" |
" |
|
|
1295 |
|
680 |
" |
" |
" |
sfh-64c300c |
2" |
300 |
|
|
267 |
|
170 |
wcb |
≤425 |
水、油品、蒸气等 |
" |
3" |
" |
|
|
318 |
|
215 |
" |
" |
" |
" |
4" |
" |
|
|
356 |
|
235 |
" |
" |
" |
" |
6" |
" |
|
|
445 |
|
300 |
" |
" |
" |
" |
8" |
" |
|
|
533 |
|
340 |
" |
" |
" |
" |
10" |
" |
|
|
622 |
|
350 |
" |
" |
" |
" |
12" |
" |
|
|
711 |
|
420 |
" |
" |
" |
" |
14" |
" |
|
|
838 |
|
480 |
" |
" |
" |
" |
16" |
" |
|
|
864 |
|
520 |
" |
" |
" |
" |
18" |
" |
|
|
978 |
|
600 |
" |
" |
" |
" |
20" |
" |
|
|
1016 |
|
670 |
" |
" |
" |
" |
24" |
" |
|
|
1346 |
|
750 |
" |
" |
" |
sfh-64c600c |
2" |
600 |
|
|
292 |
|
175 |
wcb |
≤425 |
水、油品、蒸气 |
" |
3" |
" |
|
|
356 |
|
230 |
" |
" |
" |
" |
4" |
" |
|
|
432 |
|
295 |
" |
" |
" |
" |
6" |
" |
|
|
559 |
|
360 |
" |
" |
" |
" |
8" |
" |
|
|
660 |
|
400 |
" |
" |
" |
" |
10" |
" |
|
|
787 |
|
460 |
" |
" |
" |
" |
12" |
" |
|
|
838 |
|
520 |
" |
" |
" |
" |
14" |
" |
|
|
889 |
|
560 |
" |
" |
" |
" |
16" |
" |
|
|
991 |
|
650 |
" |
" |
" |
" |
18" |
" |
|
|
1092 |
|
730 |
" |
" |
" |
" |
20" |
" |
|
|
1194 |
|
800 |
" |
" |
" |
" |
24" |
" |
|
|
1397 |
|
900 |
" |
" |
" |
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