讨厌的反义词：阀门流量计算

2020年11月19日发(作者：霍文灿)

阀门流量计算方法
发表于： 2010-1-29 9:39:55
如何使用流量系数 2. DN350 x DN300 x DN350，压力等级Class 900缩喉
How to use Cv
阀门流量系数(Cv)是表示阀门通过流体能力的数值。Cv越大，在给定压降下阀门能
够通过的流体就越多。Cv值1表示当通过压
降为1 PSI时，阀门每分钟流过1加仑15
o
C
的水。Cv值350表示当通过压降为1 PSI时，
阀门每分钟流过350加仑15
o
C的水。
Valve coefficient (Cv) is a number
which represents a valve's ability to
pass flow. The bigger the Cv, the more
flow a valve can pass with a given
pressure drop. A Cv of 1 means a valve will
pass 1 gallon per minute (gpm) of 60
o
F
water with a pressure drop (dp) of 1 PSI
across the valve. A Cv of 350 means a valve
will pass 350 gpm of 60
o
F water with a dp
of 1 PSI.
公式1
FORMULA 1
管压力密封闸阀，其它条件与例1相同，求压降。
What is the pressure drop through a 14
Class 900 Venturi pressure seal gate valve with
the same conditions as example 1.
解：采用公式1
Solution: Use formula 1.
Cv = 6285 (来自本页)
Cv = 6285 (from page 26)

3. 温度900
o
F, 压力1200 PSI，流速500,000磅小时的
蒸汽应用中压降小于5 PSI的压力等级Class 2500
闸阀的最小通径是多少？
What is the smallest Class 2500 gate valve that
will have less than a 5 PSI pressure drop in 900
o
F,
1200 PSI steam service at a flow rate of 500,000
lbshr?
解：采用公式1
Solution: Use formula 1.
F = 500,000
= 0.785 (来自900
o
F, 1200 PSIG蒸汽表)
流速：磅小时(蒸汽或水)
FLOW RATE LBSHR (Steam or Water)

在此：
Where:
dp = 压降，单位：PSI
dp = pressure drop in PSI
F = 流速，单位：磅小时
F = flow rate in .
= 比容积的平方根，单位：立方英尺
磅
(阀门下游)
= square root of a specific volume in
ft
3
lb.
(downstream of valve)
公式2
FORMULA 2
流速：加伦分钟(水或其它液体)
FLOW RATE GPM (Water or other
liquids)
= 0.785 (from chart for steam at 900
o
F, 1200 PSIG)
= = 2.24

最接近的、较大的Cv是DN250压力等级Class 2500闸
阀，其Cv是3130。这里是压降小于5 PSIG的最小的阀门。
The closest higher Cv is a 10Class 2500 gate with
a Cv of 3130. This is the smallest valve with a pressure
drop less than 5 PSIG.
水和蒸汽的备选特性
Selected Properties of Water and Steam
水的(下游)
For Water (Downstream)
所有压力等级
温度(
o
F)
All
Temperature (
o
F)
Pressures
100 200 300 400 500 600
0.127 0.129 0.132 0.137 0.143 0.154

蒸汽的(下游)
For Steam (Downstream)
压力 温度(
o
F)
PSIG Temperature (
o
F)
Pressure

在此：
Where:
dp = 压降，单位：PSI
dp = pressure drop in PSI
Sg = 比重
Sg = specific gravity
Q = 流速，单位：加伦分钟
Q = flow rate in GPM
局限性
LIMITATIONS
上列公式在下列条件下无效：
Above formulas are not valid under
the following conditions:
a. 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.
b. 对于不可压缩性流体，如果压降产生
PSIG
Sat 500 600 700 800 900 1000 1100
100 1.97 2.20 2.32 2.44 2.54 2.64 2.74 2.84
200 1.46 1.61 1.68 1.77 1.85 1.95 2.00 2.07
300 1.21 1.30 1.38 1.46 1.52 1.60 1.65 1.71
400 1.06 1.11 1.19 1.26 1.32 1.38 1.43 1.47
500 0.950 0.979 1.06 1.12 1.18 1.23 1.28 1.33
600 0.865 0.895 0.960 1.02 1.08 1.13 1.17 1.22
700 0.801 0.880 0.941 0.994 1.04 1.08 1.12
800 0.747 0.815 0.875 0.926 0.972 1.01 1.05
900 0.701 0.759 0.821 0.870 0.914 0.955 0.99
1000 0.662 0.710 0.773 0.816 0.865 0.917 0.94
1100 0.628 0.670 0.732 0.781 0.823 0.872 0.90
1200 0.598 0.629 0.695 0.745 0.785 0.813 0.86
1300 0.570 0.590 0.662 0.710 0.752 0.789 0.83
1400 0.545 0.559 0.633 0.683 0.723 0.752 0.79
1600 0.58 0.63 0.67 0.70 0.74
1800 0.54 0.59 0.63 0.66 0.69
2000 0.50 0.55 0.59 0.62 0.65
2500 0.41 0.48 0.52 0.55 0.58
3000 0.31 0.42 0.46 0.49 0.52
4000 0.17 0.32 0.38 0.42 0.44
5000 0.16 0.24 0.32 0.36 0.39
6000 0.16 0.19 0.28 0.32 0.35
空穴或闪蒸。
For non-compressible fluids, where
pressure drop causes cavitation or
flashing.
c. 对于双相流体，如蒸汽-水混合流体。
For dual-phase flow such as
steam-water mixtures.
例子
EXAMPLE
1. 通过DN350, 压力等级Class 900的压
力密封闸阀，水温400
o
F，压力为1500
PSIG，流速为5,000,000磅小时的压
降是多少？
What is the pressure drop through
a 14
valve with 400
o
F water, 1500 PSIG,
and 5,000,000 lbshr flow rate?
解：采用公式1
Solution: Use formula 1.
F = 5,000,000
= 0.137 (从水温为400
o
F的表中得到)
= 0.137 (from chart for water at
400
o
F)
Cv = 9150 (来自本页)
Cv = 9150 (from page 26)

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:
2
F()
流量(磅小时): 流速:
(英尺秒)=
25A

阀座端口面积“A”(英寸
2
)
适用于螺栓阀帽阀门
SEAT PORT AREA
BONNET VALVES (in
2
)
阀门通径
Valve Size
1
1

2

2
2
1

2

3
4
6
8
10
12
14
压力等级
Pressure Class
150 300 600 900 1500
2
F()
Flow (lbshr): vel:
(fps) =
25A
流量(加仑分钟): 流速:
0.32Q
(英尺秒)=
A
Flow (GPM): vel: (fps) =
0.32Q
1.8 1.8 1.8 1.8 1.5
3.1 3.1 3.1 3.1 2.8
4.9 4.9 – 4.9 4.0
7.1 7.1 7.1 6.5 6.0
12.6 12.6 12.6 11.8 10.3
28.3 28.3 28.3 26.0 22.7
50.3 50.3 48.7 44.2 38.5
78.5 78.5 74.7 71.0 60.0
113.1 113.1 108.4 100.0 84.5
137.9 137.9 130.2 117.9 101.6
A

在此：
Where:
F = 流量(磅小时)
F = flow (lbshr)
= 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 (in
2
)
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
o
F，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 lbshr of steam at 500
o
F and 200
PSIG?
16 182.7 182.7 170.9 – –
18 233.7 227.0 213.8 – –
20 291.0 283.5 261.6 – –
24 424.5 424.5 380.1 – –
30 671.9 672.0 590.9 – –
36 969.0 942.0 851.2 – –

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 (in
2
)
阀门通径
压力等级
Valve Size
Pressure Class
600 900 1500 2500
2
1

2
5.4 5.9 3.3 2.4
3 5.4 5.9 4.9 3.6
4 9.6 10.3 8.3 5.9
6 23.2 21.7 18.9 12.6
8 39.9 37.7 31.9 21.7
10 61.0 58.4 48.7 34.5
12 88.7 80.5 69.0 47.2
14 – 97.2 82.5 58.2
16 – 125.2 108.4 76.6
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 in
2
.
90,000
流速: (英
F()
2

(1.61)
2

= 118.8 英
尺秒)=
=
25A
尺秒
25 (78.5)
F()
2

90,000
Vel (fps) = =
(1.61)
2

= 118.8 fps
25A
25 (78.5)
例：
DN300型号180 (压力等级150)旋启式止回阀，
流体介质为温度500
o
F，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 lbshr of steam at 500
o
F
and 200 PSIG?
18 173.8 156.7 137.9 97.2
20 – 198.0 170.9 117.9
24 310.25 287.3 247.5 170.9

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 (in
2
)
阀门通径
压力等级
Valve Size
Pressure Class
900 1500 2500
8 39.9 39.9 27.2
10 61.9 61.9 42.8
12 86.6 86.6 60.1
14 86.6 86.6 86.6
16 135.4 135.4 86.6
18 135.4 135.4 135.4
20 198.1 198.1 135.4
24 302.6 302.6 198.1
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
3
in.
2
F()
流速: (英
=
尺秒)=
25A
90,000
(1.61)
2

25 (113.1)
90,000
(1.61)
2

25 (113.1)
= 82.5英尺
秒
F()
2

Vel (fps) = =
25A
= 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:
a. 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.
b. 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.
c. 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
螺栓阀帽闸阀全开状态下的流量系数Cv



螺栓阀盖旋启式止回阀全开状态下的流量系数Cv
Bolted Bonnet
Gate Valves FULL OPEN Cv
阀门通径
压力等级
Valve
Pressure Class
Size
150 300 600 900 1500
1
1

2
165 165 165 – 138
2 307 307 307 – 270
2
1

2
490 490 490 – 400
3 710 710 710 650 600
4 1300 1300 1300 1220 1070
5 2090 – – – 1600
6 3110 3110 3110 2850 2500
8 5720 5720 5540 5025 4375
10 8935 8935 8495 7850 6840
12 13350 13350 12800 11475 9980
14 16275 16275 15370 13910 12000
16 21560 21560 29170 – –
18 28720 27890 26270 – –
20 35760 34840 32140 – –
24 52165 51050 46710 – –
Bolted Cap
Swing Check Valves FULL OPEN Cv
阀门通径
压力等级
Valve Size
Pressure Class
150 300 600 900 1500
1
1

2
63 63 97 – –
2 142 168 139 – 111
2
1

2
217 275 227 – –
3 356 392 246 358 315
4 716 740 499 605 564
6 1414 1992 1334 1623 1520
8 2961 2340 3359 2508 –
10 5720 5720 5440 4069 –
12 7860 8544 7045 6316 –
14 10416 19464 9840 – –
16 13800 13800 12912 – –
18 13420 13029 – – –
20 16708 16276 19540 – –
24 33384 36672 – – –
30 54556 54652 – – –
30 86235 84765 75530 – –
36 129500 125825 114250 – –

图1
螺栓阀帽截
止阀
Figure 1
Bolted
Bonnet
Globe
Valves
(1)当开启度
小于
10%时，不建
议
用于节流应
用。
(1) not
recommended
for
throttling
at less
than 10%
Open.

螺栓阀帽截止阀全开状态下的流量系数Cv
Bolted Bonnet
Globe Valves FULL OPEN Cv
压力等级
Pressure Class
150 300 600 900
阀门
塞形 塞形 塞形 塞形
通径
或
球形
V形
或
V形
或
V形
或
Valve
端口
球形
端口
球形
阀瓣
端口
球形
Size
阀瓣
Plug
阀瓣
阀瓣
阀瓣 阀瓣
阀瓣
or
V-Port
Plug
V-Port
Plug Plug
Ball
Disc
or or
V-Port
or
Ball
Disc
Ball
Disc
Ball
Disc Disc Disc Disc
1
1

2
23 – 23 21 23 – –
2 43 40 43 40 43 40 –
2
1

2
70 – 70 – 70 – –
3 100 92 100 92 100 92 90
4 185 170 185 170 185 170 170
5 297 273 – – – – –
6 440 405 440 405 440 405 –
8 810 745 810 745 780 – –

压力密封闸阀全开状态下的流量系数Cv
Pressure Seal
Gate Valves FULL OPEN Cv
阀门通径
压力等级
Valve Size
Pressure Class
600 900 1500 2500
2
1

2
350 350 275 190
3 525 450 415 275
4 925 850 730 460
6 2150 1925 1675 1100
8 3775 3575 2925 1970
10 5750 5250 4550 3130
12 8600 7550 6570 4535
14 10275 9150 7890 5500
16 13425 11950 10325 7210
18 17200 15575 13425 9215
20 20950 19200 16825 11450
24 30850 27675 24150 16575

压力密封缩喉管闸阀全开状态下的流量系数Cv
Pressure Seal
Venturi Gate Valves FULL OPEN Cv
10 1260 1150 1260 – – – –
12 1890 – 1890 – 1810 – –

压力密封提升式阀瓣止回阀全开状态下的流量系数Cv
Pressure Seal
Tilting Disc Check Valves FULL OPEN Cv
阀门通径
压力等级
Valve Size
Pressure Class
900 1500 2500
2
1

2
95 80 60
3 146 132 94
4 268 230 146
6 627 536 355
8 1062 940 627
10 1722 1465 1020
12 2420 2110 1420
14 2955 2550 1775
16 3945 3395 2355
18 4900 4365 3025
20 6275 5465 3705
24 9295 8060 5465

阀门通径
Valve Size
8 x 6 x 8
10 x 8 x 10
12 x 10 x 12
14 x 12 x 14
16 x 14 x 16
18 x 16 x 18
20 x 18 x 20
22 x 20 x 22
26 x 24 x 26
压力等级
Pressure Class
600
1570
2795
4485
7310
9000
11000
14200
16800
25000
900
1385
2385
4065
6285
7200
9760
12185
16005
23000
1500 2500
1185
2155
3450
5640
6270
8465
11120
14130
–
815
1430
2515
3855
4415
6165
7960
9645
–
压力密封缩喉管提升式阀瓣止回阀全开状态下的流量
系数Cv
Pressure Seal
Venturi Tilting Disc Check Valves FULL OPEN Cv
阀门通径
Valve Size
8 x 6 x 8
10 x 8 x 10
12 x 10 x 12
14 x 12 x 14
16 x 14 x 16
18 x 16 x 18
20 x 18 x 20
22 x 20 x 22
压力等级
Pressure Class
150
565
955
1550
2175
2660
3550
4410
5650
300
480
845
1320
1900
2295
3055
3930
4920
600
320
565
920
1275
1598
2120
2725
3335
球形止回阀，截止止回阀，提升式止回阀的流量特性曲线
Characteristic Flow Curves for Globe Stop, Stop-Check, Lift-Check Valves
小于全开状态的估计流量系数Cv
Estimating Cv For Less Than Fully Open Valves


图2
球形止回阀，截止止回阀和提升式止回阀
Figure 2
Globe Stop, Stop-Check and
Lift-Check Valves
压力密封T形球形止回阀，截止止回阀和提升式止
回阀
阀全开状态下的流量系数Cv
Pressure Seal T-Globe Stop,
Stop-Check and Lift-Check Valves FULL OPEN Cv

图3
Y形球形止回阀，截止止回阀和提升式止回阀
Figure 3
Y-Globe Stop, Stop-Check and
Lift-Check Valves
压力密封缩喉管球形止回阀，截止止回阀和提升式
止回阀
阀全开状态下的流量系数Cv
Pressure Seal Venturi Globe Stop,
Stop-Check and Lift-Check Valves FULL OPEN Cv
阀门通径 压力等级
阀门通径
压力等级
Valve Size
Pressure Class
900 1500 2500
2
1

2
90 65 45
3 105 95 65
4 195 170 105
6 455 395 265
8 800 695 470
10 1250 1085 750
12 1820 1580 1100
14 2205 – –

压力密封Y球形止回阀，截止止回阀和提升式止回
阀
阀全开状态下的流量系数Cv
Pressure Seal Y-Globe Stop,
Stop-Check and Lift-Check Valves FULL OPEN Cv
Valve Size Pressure Class
900 1500 2500
8 x 6 x 8 450 390 260
10 x 8 x 10 770 690 465
12 x 10 x 12 1215 1055 745
14 x 12 x 14 1775 1550 1070
16 x 14 x 16 2125 – –

压力密封缩喉管Y球形止回阀，截止止回阀和提升
式止回阀
阀全开状态下的流量系数Cv
Pressure Seal Venturi Y-Globe Stop,
Stop-Check and Lift-Check Valves FULL OPEN Cv
阀门通径
压力等级
Valve Size
Pressure Class
600 900 1500 2500
8 x 6 x 8 1100 1000 1000 650
10 x 8 x 10 1925 1675 1675 1125
12 x 10 x 12 2875 2600 2600 1775
14 x 12 x 14 4375 3650 3650 2525
16 x 14 x 16 4075 3450 3450 3875
18 x 16 x 18 7250 5700 5700 3575
20 x 18 x 20 6950 5525 5525 6300

阀门通径
压力等级
Valve Size
Pressure Class
600 900 1500 2500
8 2025 1750 1750 1175
10 3025 2725 2725 1875
12 4600 3825 3825 2650
14 4300 3650 3650 4075
16 7650 6000 6000 3775
18 7325 5825 5825 6625
20 11800 9125 9125 6225
24 16450 13500 13500 9050
表中所列流量系数仅适用于全开状态下的阀
门。不是全开状态的流量系数可以采用适用于提 升
式阀瓣止回阀和截止阀的流量特性曲线进行估算。
不建议将闸阀用在节流应用中。
The flow coefficient (Cv) listed in the
tables apply to fully open valves only. Flow
coefficients at other than fully open may be
approximated by use of the characteristic flow
curves for tilting disc check and globe valves.
Gate valves are not recommended for throttling
service.
例：
22 x 20 x 22 11200 8675 8675 5925
16 x 24 x 26 15850 12825 12825 8600
解：
从上列流量系数表中得到，DN300，压力等级
Class 900截止阀在全开状态下的Cv是1820。
SOLUTION:
From the flow coefficient table above, the
fully open Cv for a 12 inch, Class 900 globe
valve is 1820.
查询图2，全开状态的14时阀门的比率是52%.
Consulting Figure 2, the percent of fully
open Cv at 14 valve open is 52%.
因此计算14全开的流量系数Cv为：
0.52 x 1820 = 946.
The Cv at 14 open is then computed as:
0.52 x 1820 = 946.
DN300，压力等级Class 900的美国太平洋压力
密封截止阀在开气度为14时的流量系数是多少？
EXAMPLE:
What is the Cv of a 12 inch Class 900 Pacific
pressure seal globe valve 14 open?