阀座端口流速计算 Calculating Seat Port Velocity
下列公式可以用来计算任何阀门的阀座流速: The following formulas can be used to calculate seat port velocity in any valve:
流量(磅/小时): 流速: (英尺/秒)= |
F()2 |
|
25A | |
Flow (lbs/hr): vel: (fps) = |
F()2 |
|
25A | |
流量(加仑/分钟): 流速: (英尺/秒)= |
|
Flow (GPM): vel: (fps) = |
|
F |
= |
流量(磅/小时) |
F |
= |
flow (lbs/hr) |
|
= |
比容积的平方根 |
|
= |
square root of specific volume |
A |
= |
阀座端口面积 (英寸2) |
A |
= |
seat port area (in2) |
Q |
= |
流量 (加仑/分钟) |
Q |
= |
flow (gpm) |
例: DN300型号58809 (压力等级Class 900)止回阀,流体介质为温度500 oF,压力200 PSIG的蒸汽,流速为90,000磅/小时,求阀座端口的流速? Example: What is the seat port velocity in a 12" Figure 58809 (Class 900) check valve with a flow rate of 90,000 lbs/hr of steam at 500 oF and 200 PSIG?
解: 从蒸汽表得为1.61,从阀座端口面积表A得阀座端口面积为78.5英寸2。 Answer: From the steam tables is 1.61, and from the seat port area table A is 78.5 in2.
流速: (英尺/秒)= |
F()2 |
|
25A | |
= |
|
= 118.8 英尺/秒 |
Vel (fps) = |
F()2 |
|
25A | |
= |
|
= 118.8 fps |
例: DN300型号180 (压力等级150)旋启式止回阀,流体介质为温度500oF,压力200 PSIG的蒸汽,流速为90,000磅/小时,求阀座端口流速? Example: What is the seat port velocity in a 12" Figure 180 (Class 150) Swing Check Valve with a flow rate of 90,000 lbs/hr of steam at 500oF and 200 PSIG?
解: 查表得为1.61,A为 113.1英寸3. Answer: From the tables is 1.61 and A is 113.1 in3.
流速: (英尺/秒)= |
F()2 |
|
25A | |
= |
90,000 (1.61)2 |
|
25 (113.1) | |
= 82.5英尺/秒 |
Vel (fps) = |
F()2 |
|
25A | |
= |
90,000 (1.61)2 |
|
25 (113.1) | |
= 82.5 fps |
局限性 LIMITATIONS
流速公式在下列条件下无效: Velocity formulas are not valid under the following conditions:
- 对于可压缩性流体,如果压降超过进口压力的一半。
For compressible fluids, where pressure drop exceeds half the inlet pressure.
- 对于不可压缩性流体,如果压降产生空穴或闪蒸。
For non-compressible fluids, where pressure drop causes cavitation or flashing.
- 对于双相流体,如蒸汽-水混合流体。
For dual-phase flow such as steam-water mixtures.
注意 NOTE
在确定止回阀通径时,最适宜的工作流速应该位于这些范围内: When determining sizing for check valves, the optimum operating velocities should fall within these ranges:
BB旋启式止回阀:55 至115或135至240 BB截止止回阀:40 至120 PS提升式阀瓣止回阀:55至200 PSY形止回阀:148 至200 BB Swing Check Valves - 55 to 115 or 135 to 240 BB Stop Check Valves - 40 to 120 PS Tilt Disc Check Valves - 55 to 200 PS Stop Check Valves - 40 to 180 PS Y- Stop Check Valves - 148 to 200 |
|
阀座端口面积“A”(英寸2) 适用于螺栓阀帽阀门 SEAT PORT AREA "A" FOR BOLTED BONNET VALVES (in2) |
阀门通径 Valve Size |
压力等级 Pressure Class |
150 |
300 |
600 |
900 |
1500 |
11/2 2 21/2 3 4 6 8 10 12 14 16 18 20 24 30 36 |
1.8 3.1 4.9 7.1 12.6 28.3 50.3 78.5 113.1 137.9 182.7 233.7 291.0 424.5 671.9 969.0 |
1.8 3.1 4.9 7.1 12.6 28.3 50.3 78.5 113.1 137.9 182.7 227.0 283.5 424.5 672.0 942.0 |
1.8 3.1 – 7.1 12.6 28.3 48.7 74.7 108.4 130.2 170.9 213.8 261.6 380.1 590.9 851.2 |
1.8 3.1 4.9 6.5 11.8 26.0 44.2 71.0 100.0 117.9 – – – – – – |
1.5 2.8 4.0 6.0 10.3 22.7 38.5 60.0 84.5 101.6 – – – – – – |
阀座端口面积(英寸2) 适用于压力密封闸阀,截止阀,提升式阀瓣止回阀 SEAT PORT AREA FOR PRESSURE SEAL GATE, GLOBE, TILT DISC CHECK VALVES (in2) |
阀门通径 Valve Size |
压力等级 Pressure Class |
600 |
900 |
1500 |
2500 |
21/2 3 4 6 8 10 12 14 16 18 20 24 |
5.4 5.4 9.6 23.2 39.9 61.0 88.7 – – 173.8 – 310.25 |
5.9 5.9 10.3 21.7 37.7 58.4 80.5 97.2 125.2 156.7 198.0 287.3 |
3.3 4.9 8.3 18.9 31.9 48.7 69.0 82.5 108.4 137.9 170.9 247.5 |
2.4 3.6 5.9 12.6 21.7 34.5 47.2 58.2 76.6 97.2 117.9 170.9 |
阀座端口面积(英寸2) 适用于压力密封Y形截止阀 SEAT PORT AREA FOR PRESSURE SEAL Y-GLOBE VALVES (in2) |
阀门通径 Valve Size |
压力等级 Pressure Class |
900 |
1500 |
2500 |
8 10 12 14 16 18 20 24 |
39.9 61.9 86.6 86.6 135.4 135.4 198.1 302.6 |
39.9 61.9 86.6 86.6 135.4 135.4 198.1 302.6 |
27.2 42.8 60.1 86.6 86.6 135.4 135.4 198.1 | |