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，{zh0}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
|
"
|
"
|
"
|