止回閥是能自動阻止流體倒流的閥門。止回閥的閥瓣在流體壓力作用下開啟，流體從進口側流向出口側。當進口側壓力低于出口側時，閥瓣在流體壓差、本身重力等因素作用下自動關閉以防止流體倒流。
止回閥一般分為升降式、旋啟式等幾種類型。
升降式止回閥的結構一般與截止閥相似，其閥瓣沿著通道中心線作升降運動，動作可靠，但流體阻力較大，適用于較小口徑的場合。升降式止回閥可分為直通式和立式兩種。直通式升降式止回閥一般只能安裝在水平管路，而立式升降止回閥一般應安裝在垂直管路。
旋啟式止回閥的閥瓣繞轉軸作旋轉運動。其流體阻力一般小于升降式止回閥，它適用于較大口徑的場合。旋啟式止回閥根據閥瓣的數目可分為單瓣旋啟式、雙瓣旋啟式及多瓣旋啟式三種。單瓣旋啟式止回閥一般適用于中等口徑的場合。大口徑管路選用單瓣旋啟式止回閥時，為減少水錘壓力，{zh0}采用能減小水錘壓力的緩閉止回閥。雙瓣旋啟式止回閥適用于大中口徑管路。對夾雙瓣旋啟式止回閥結構小、重量輕，是一種發(fā)展較快的止回閥；多瓣旋啟式止回閥適用于大口徑管道路。
主要零件材料及性能規(guī)范
|
主 要 零 部 件
|
閥體、閥蓋、搖桿
|
WCB
|
CF8
|
CF8M
|
WC6、WC9
|
|
閥瓣
|
WCB堆Cr13或硬質合金
|
CF8堆硬質合金
|
CF8M堆硬質合金
|
WC6、WC9堆硬質合金
|
|
閥座
|
25堆Cr13或硬質合金
|
304堆硬質合金
|
316堆硬質合金
|
20Cr1MoV堆硬質合金
|
|
墊片
|
軟鐵、XB450
|
聚四氟乙烯
|
聚四氟乙烯
|
不銹鋼+耐酸石棉纏繞墊
|
|
螺栓
|
35CrMoA
|
35CrMoA
|
35CrMoA
|
25Cr1Mo1V
|
|
螺母
|
45
|
45
|
45
|
35CrMoA
|
|
主要參數
|
適用介質
|
油品、水、蒸汽
|
硝酸類
|
醋酸類
|
油品、水、蒸汽
|
|
適用溫度
℃
|
≤425
|
≤200
|
≤200
|
≤550
|
|
型號
|
公稱
通徑
NPS(in)
|
壓力級
Class
|
主要結構尺寸(mm)
|
閥體
材料
|
性能規(guī)范
|
|
D
|
D1
|
L
|
L1
|
H
|
適用溫度(℃)
|
適用介質
|
|
SFH-64C150C
|
2"
|
150
|
|
|
203
|
|
170
|
WCB
|
≤425
|
水、油品、蒸氣等
|
|
"
|
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、蒸氣等
|
|
"
|
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、蒸氣
|
|
"
|
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
|
"
|
"
|
"
|