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The Ultimate Valve Cv Sheets

Valve Cv applies to the coefficient of pressure drop(ΔP) or head drop (Δh) on the valve of Q(flow capacity). This article will tell you everything about the valve cv.
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    What is a Cv?

    Control valve CV refers to the flow coefficient of the valve. It applies to the coefficient of pressure drop(ΔP) or head drop (Δh) on the valve of Q(flow capacity).

    For more definitions and related information, please read this article.

    Flow Coefficient Calculation Cv

    The flow rate of a liquid or gas through a valve depends on many factors such as density, temperature, gravity, and the pressure drop of the liquid or gas through the valve. The design type and flow path of the valve has a different effect on the flow rate through the valve. Considering the relationship between temperature, gravity, and pressure drop through the valve, a “flow coefficient” can be calculated to determine the theoretical flow rate through the valve. This coefficient is called Cv (coefficient of flow) and it is developed by the flow capacity testing from the manufacturer.

    Liquids: 

    liquid valve cv

    Equation Abbreviations – Liquids:

    Q = Flow (Barrels/Day)

    Cv= Flow Factor

    ΔP = Pressure Drop Across Valve

    G = Specific Gravity (Water=1.0)

    Gas:

    gas valve cv

    Equation Abbreviations – Gas:

    Q = Flow (MMSCFD)

    Cv = Flow Factor

    P1 = Inlet Pressure (psia)

    P2 = Outlet Pressure (psia)

    ΔP = Pressure drop (P1-P2). When P2 is less than 1/2 P1, use 1/3 P1, for P2 in the formula.

    G = Specific Gravity (air=1.0)

    T = Flowing Temperature Absolute (°F + 460)

    If flow capacity required is known and valve selection is desired, calculate Cv with the following formula and select the appropriate valve from the manufacturer’s Cv factor chart.

    Liquids:     

    valve cv for liquids

    Gas:

    valve cv for gas

    Butterfly Valve Cv Flow Rate

    Generally, we work on metric systems, but many engineers still prefer to express flow coefficients in terms of Cv values. The imperial system measures flow in US GPM at 60 degrees Fahrenheit with a pressure drop of 1 psi across the valve. The following table shows the flow rate of a butterfly valve between 0°(fully closed) and 90° (fully open) with the valve at different openings. Please notice that the Cv value is not a linear increment, so it cannot be deduced just by looking at the value. These sheets of flow coefficients are just for your reference. 

    pressure temperature chart for butterfly valve material2 1
    pressure temperature chart for butterfly valve material
    pressure temperature chart for butterfly valve material
    pressure temperature chart for butterfly valve material

    Triple Offset Butterfly Valve Cv 150LB

    butterfly valves
    butterfly valves
    lug type butterfly valves
    lug type butterfly valves
    butterfly valve cv value 150lb

    Triple Offset Butterfly Valve Cv 300LB

    wafer type butterfly valves1
    wafer-type butterfly valves
    welded ends butterly valves
    welded ends butterfly valves
    butterfly valve cv value 300lb

    High-Performance Butterfly Valve Cv

    high performance butterfly valve cv

    Resilient Seated Butterfly Valves Cv

    Cv Value at different degrees of opening

    inchmm10°20°30°40°50°60°70°80°90°
    2500.151224456490125135
    2 1/2650.2820376598144204220
    3800.312223970116183275302
    41000.5173678139230364546600
    51250.829611332373926209301022
    61502459520536660595814371579
    82003891884087271202190328543136
    10250415132069412372047324048595340
    123005234495107219113162500575078250
    14350633871515492761456872301084411917
    16400846498321303797628299421491316388
    18450116151302282250288320131681975221705
    205001479116743628646510698169312539627908
    225501796520424426788713052206553098334048
    2460022122225875605998916528261573923643116
    26650261434303665781172319397292634604750600
    28700301663352276301259920036304824689958696
    30750351912405081421315220411312264756263328
    32800452387479187361378820613313954811768250
    34850512697541498721558023293354765437277123
    369006030216063110551744926086397316089586375
    40100084418383951530724159361665508484425119750
    4210503504095904017108271504364070500106890117500
    48120045553651184022400306005120092300140000154000

    Ball Valves Cv Flow Rate

    The Cv values below are used to indicate the flow rate of the ball valve. Different ball type has different Cv flow rate. Hope it will be useful for your case. 

    V-Port Ball Valve Cv

    Valve SizeBall Angle15%20%30%40%50%60%70%80%90%100%
    1/2″30°0.10.10.20.30.50.81.11.62.22.6
    1/2″60°0.10.10.30.50.91.423.34.46
    3/4″30°0.10.20.50.71.11.82.43.34.55.4
    3/4″60°0.10.20.711.72.846.5912
    1″30°0.10.30.81.32.33.55.19.88.510
    1″60°0.20.41.11.83.45.37.912.315.321
    1 1/4″30°0.20.41.123.75.58101315
    1 1/4″60°0.20.61.835.59.512.8192639
    1 1/2″30°0.30.61.6357.511141720
    1 1/2″60°0.40.82.5481319274052
    2″30°0.41.23.86101523314360
    2″60°0.41.54.6916.527395583110
    2 1/2″30°0.4148121828376275
    2 1/2″60°0.41.551021345375103150
    3″30°0.51.248142333466582
    3″60°0.52.561425406591128165
    4″30°0.62615294871100130159
    4″60°0.731125405990141212356
    6″30°0.93.2143360103155220280350
    6″60°252260110190285416586800

    Flow Rate for two-way Full Bore Ball Valve Cv

    Valve SizeDN (mm)Cv when fully open
    ¼”818
    ⅜”1020
    ½”1523
    ¾”2055
    1”2595
    1 ¼”32155
    1 ½”40260
    2”50440
    2 ½”65710
    3”801050
    4”1002040

    3 Way Full Bore Flanged Ball Valve Cv

    Valve SizeCvKv (m3/h)
    1/2″15.213
    3/4″23.320
    1″45.539
    1-1/4″58.450
    1-1/2″11296
    2″224.1192
    2-1/2″308.1264
    3″409.6351
    4″762.1653

    3 Way Reduced Port Threaded Ball Valve Cv

    Valve SizeCvKv (m3/h)
    1/4″12.811
    3/8″12.811
    1/2″15.213
    3/4″17.515
    1″36.231
    1-1/4″45.539
    1-1/2″72.462
    2″120.2103
    2-1/2″239.2205
    3″270.7232
    4″480.8412

    Globe Type Control Valve Cv Flow Rate

    6inch 300lb cf8 control valve manufacturer
    6inch 300lb cf8 control valve manufacturer
    high quality control valve cv manufacturer supplier
    high quality control valve cv manufacturer supplier
    cv value
    pressure control valves manufacturer in china thinktank 1
    pressure control valves manufacturer in china thinktank

    Gate Valve Cv

    Bolted Bonnet Gate Valve Cv (Full Open)

    Valve Size150LB300LB600LB900LB1500LB
    11/2
    2
    21/2
    3
    4
    5
    6
    8
    10
    12
    14
    16
    18
    20
    24
    30
    36
    165
    307
    490
    710
    1300
    2090
    3110
    5720
    8935
    13350
    16275
    21560
    28720
    35760
    52165
    86235
    129500
    165
    307
    490
    710
    1300

    3110
    5720
    8935
    13350
    16275
    21560
    27890
    34840
    51050
    84765
    125825
    165
    307
    490
    710
    1300

    3110
    5540
    8495
    12800
    15370
    29170
    26270
    32140
    46710
    75530
    114250



    650
    1220

    2850
    5025
    7850
    11475
    13910





    138
    270
    400
    600
    1070
    1600
    2500
    4375
    6840
    9980
    12000





    Pressure Seal Gate Valve Cv (Full Open)

    Valve Size600LB900LB1500LB2500LB
    21/2
    3
    4
    6
    8
    10
    12
    14
    16
    18
    20
    24
    350
    525
    925
    2150
    3775
    5750
    8600
    10275
    13425
    17200
    20950
    30850
    350
    450
    850
    1925
    3575
    5250
    7550
    9150
    11950
    15575
    19200
    27675
    275
    415
    730
    1675
    2925
    4550
    6570
    7890
    10325
    13425
    16825
    24150
    190
    275
    460
    1100
    1970
    3130
    4535
    5500
    7210
    9215
    11450
    16575

    Pressure Seal Venturi Gate Valve Cv (Full Open)

    Valve Size600LB900LB1500LB2500LB
    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
    1570
    2795
    4485
    7310
    9000
    11000
    14200
    16800
    25000
    1385
    2385
    4065
    6285
    7200
    9760
    12185
    16005
    23000
    1185
    2155
    3450
    5640
    6270
    8465
    11120
    14130
    815
    1430
    2515
    3855
    4415
    6165
    7960
    9645

    Check Valve Cv

    Bolted Cap Swing Check Valve Cv (Full Open)

    Valve Size150LB300LB600LB900LB1500LB
    11/2
    2
    21/2
    3
    4
    6
    8
    10
    12
    14
    16
    18
    20
    24
    30
    63
    142
    217
    356
    716
    1414
    2961
    5720
    7860
    10416
    13800
    13420
    16708
    33384
    54556
    63
    168
    275
    392
    740
    1992
    2340
    5720
    8544
    19464
    13800
    13029
    16276
    36672
    54652
    97
    139
    227
    246
    499
    1334
    3359
    5440
    7045
    9840
    12912

    19540




    358
    605
    1623
    2508
    4069
    6316






    111

    315
    564
    1520








    Pressure Seal Tilting Disc Check Valve Cv (Full Open)

    Valve Size900LB1500LB2500LB
    21/2
    3
    4
    6
    8
    10
    12
    14
    16
    18
    20
    24
    95
    146
    268
    627
    1062
    1722
    2420
    2955
    3945
    4900
    6275
    9295
    80
    132
    230
    536
    940
    1465
    2110
    2550
    3395
    4365
    5465
    8060
    60
    94
    146
    355
    627
    1020
    1420
    1775
    2355
    3025
    3705
    5465

     Pressure Seal Venturi Tilting Disc Check Valve Cv (Full Open)

    Valve Size150LB300LB600LB
    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
    565
    955
    1550
    2175
    2660
    3550
    4410
    5650
    480
    845
    1320
    1900
    2295
    3055
    3930
    4920
    320
    565
    920
    1275
    1598
    2120
    2725
    3335

    Globe Valve, Stop-Check Valve, and Lift-Check Valve Cv

    Pressure Seal T-Globe Stop, Stop-Check, and Lift-Check Valve Cv (Full Open)

    Valve Size900LB1500LB2500LB
    21/2
    3
    4
    6
    8
    10
    12
    14
    90
    105
    195
    455
    800
    1250
    1820
    2205
    65
    95
    170
    395
    695
    1085
    1580
    45
    65
    105
    265
    470
    750
    1100

    Pressure Seal Venturi Globe Stop, Stop-Check, and Lift-Check Valve Cv (Full Open)

    Valve Size900LB1500LB2500LB
    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
    450
    770
    1215
    1775
    2125
    390
    690
    1055
    1550
    260
    465
    745
    1070

    Pressure Seal Venturi Y-Globe Stop, Stop-Check, and Lift-Check Valve Cv (Full Open)

    Valve Size600LB900LB1500LB2500LB
    8
    10
    12
    14
    16
    18
    20
    24
    2025
    3025
    4600
    4300
    7650
    7325
    11800
    16450
    1750
    2725
    3825
    3650
    6000
    5825
    9125
    13500
    1750
    2725
    3825
    3650
    6000
    5825
    9125
    13500
    1175
    1875
    2650
    4075
    3775
    6625
    6225
    9050

    Globe Valve Cv

    Bolted Bonnet Globe Valve Cv (Full Open)

    Valve SizePlug or
    Ball
    Disc (150LB)
    V-Port
    Disc (150LB)
    Plug or
    Ball
    Disc (300LB)
    V-Port
    Disc (300LB)
    Plug or
    Ball
    Disc (600LB)
    V-Port
    Disc (600LB)
    Plug or
    Ball
    Disc (900LB)
    11/2
    2
    21/2
    3
    4
    5
    6
    8
    10
    12
    23
    43
    70
    100
    185
    297
    440
    810
    1260
    1890

    40

    92
    170
    273
    405
    745
    1150
    23
    43
    70
    100
    185

    440
    810
    1260
    1890
    21
    40

    92
    170

    405
    745

    23
    43
    70
    100
    185

    440
    780

    1810

    40

    92
    170

    405





    90
    170




    Seat Port Area For Pressure Seal Y-Type Globe Valves Cv (in2)

    Valve Size900LB1500LB2500LB
    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

    How to Use Valve Cv?

    The valve coefficient (Cv) is a number that 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 60oF water with a pressure drop (dp) of 1 PSI across the valve. A Cv of 350 means a valve will pass 350 GPM of 60oF water with a dp of 1 PSI.

    Equation 1: Flow Capacity LBS/Hr (steam or water)

    flow rate dp or cv

    dp= pressure drop in PSI

    F=flow rate in lbs./hr.

    specific volume=square root of a specific volume in ft3/lb. (downstream of the valve)

    Equation 2: Flow Capacity GPM (Water or other liquids)

     flow rate gpm water or other liquids

    dp= pressure drop in PSI

    Sg=specific gravity

    Q=flow rate in GPM

    Restrictions

    The velocity equation is invalid under the following conditions.

    a. For compressible fluids, the pressure drop is more than half of the inlet pressure.

    b. For incompressible fluids, when the pressure drop causes cavitation or flashing.

    c. For two-phase flows, such as a mixture of steam and water.

    The optimum operating speed should be within these ranges when sizing check valves as below.

    sizing for check valve 1

    Question A:

    What is the pressure drop through a 14″ Class 900 pressure seal gate valve with 400oF water, 1500 PSIG, and 5,000,000 lbs/hr flow rate?

    Answer A: Use Equation 1

    F=5,000,000

    specific volume=0.137 (from the chart for water at 400oF)

    Cv=9150 (from pressure seal gate valve Cv sheet)

    Question B:

    What is the pressure drop through a 14″x12″x14″ Class 900 Venturi pressure seal gate valve with the same conditions as question A.

    Answer B: Use Equation 1

    Cv = 6285 (from Venturi pressure seal gate valve Cv Sheet)

    solution 2 dp

    Question C:

    What is the smallest Class 2500 gate valve that will have less than a 5 PSI pressure drop in 900oF, 1200 PSI steam service at a flow rate of 500,000 lbs/hr?

    Answer C: Use Equation1.

    F=500,000

    specific volume=0.785 (from chart for steam at 900oF, 1200 PSIG)

    dp root=root 5=2.24

    cv for solution3

    The closest higher Cv is a 10″ Class 2500 gate with a Cv of 3130. This is the smallest valve with a pressure drop of less than 5 PSIG.

    Selected Properties of Water and Steam

    specific volumeFor Water (Downstream)

    Temperature100oF200oF300oF400oF500oF600oF
    All Pressures specific volume0.1270.1290.1320.1370.1430.154

    specific volumeFor Steam (Downstream)

    Pressure PSIGSat500oF600oF700oF800oF900oF1000oF1100oF
    100
    200
    300
    400
    500
    600
    700
    800
    900
    1000
    1100
    1200
    1300
    1400
    1600
    1800
    2000
    2500
    3000
    4000
    5000
    6000
    1.97
    1.46
    1.21
    1.06
    0.950
    0.865
    0.801
    0.747
    0.701
    0.662
    0.628
    0.598
    0.570
    0.545
    2.20
    1.61
    1.30
    1.11
    0.979
    0.895
    2.32
    1.68
    1.38
    1.19
    1.06
    0.960
    0.880
    0.815
    0.759
    0.710
    0.670
    0.629
    0.590
    0.559
    2.44
    1.77
    1.46
    1.26
    1.12
    1.02
    0.941
    0.875
    0.821
    0.773
    0.732
    0.695
    0.662
    0.633
    0.58
    0.54
    0.50
    0.41
    0.31
    0.17
    0.16
    0.16
    2.54
    1.85
    1.52
    1.32
    1.18
    1.08
    0.994
    0.926
    0.870
    0.816
    0.781
    0.745
    0.710
    0.683
    0.63
    0.59
    0.55
    0.48
    0.42
    0.32
    0.24
    0.19
    2.64
    1.95
    1.60
    1.38
    1.23
    1.13
    1.04
    0.972
    0.914
    0.865
    0.823
    0.785
    0.752
    0.723
    0.67
    0.63
    0.59
    0.52
    0.46
    0.38
    0.32
    0.28
    2.74
    2.00
    1.65
    1.43
    1.28
    1.17
    1.08
    1.01
    0.955
    0.917
    0.872
    0.813
    0.789
    0.752
    0.70
    0.66
    0.62
    0.55
    0.49
    0.42
    0.36
    0.32
    2.84
    2.07
    1.71
    1.47
    1.33
    1.22
    1.12
    1.05
    0.99
    0.94
    0.90
    0.86
    0.83
    0.79
    0.74
    0.69
    0.65
    0.58
    0.52
    0.44
    0.39
    0.35

    Calculating Seat Port Velocity

    The following formulas can be used to calculate seat port velocity in any valve:

    Flow (lbs/hr): vel: (fps) = F(specific volume)2  /25A

    Flow (GPM): vel: (fps) = 0.32Q/A

    Where: F=flow (lbs/hr)

    specific volume=square root of specific volume

    A=seat port area (in2)

    Q=flow (GPM)

    Case A:

    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?

    Solution A:

    From the steam sheet is 1.61, and from the seat port area sheet A is 78.5 in2.

    Vel (fps) =F(specific volume)2 /25A    = 90,000 (1.61)2  /25(78.5)= 118.8 fps

    Case B:

    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?

    Solution B:

    From the Sheet specific volumeis 1.61 and A is 113.1 in3.

    Vel (fps) =F(specific volume)2 /25A =90,000 (1.61)2/25(113.1)= 82.5 fps

    Figure 1 Bolted Bonnet Globe Valves

    figure 1

    Characteristic Flow Curves for Globe Stop, Stop-Check, Lift-Check Valves

    Estimating Cv For Less Than Fully Open Valves

    Figure 2. Globe Stop, Stop-Check, and Lift-Check Valves

    figure 2

    Figure 3. Y-Globe Stop, Stop-Check and Lift-Check Valves

    figure 3

    The flow coefficient (Cv) listed in the tables applies to fully open valves only. Flow coefficients 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.

    Case 3:

    What is the Cv of a 12 inch Class 900 Pacific pressure seal globe valve 1/4 open?

    Solution 3:

    From the flow coefficient table above, the fully open Cv for a 12 inch, Class 900 globe valve is 1820.

    Consulting Figure 2, the percent of fully open Cv at 1/4 valve open is 52%.

    The Cv at 1/4 open is then computed as:

    0.52 x 1820 = 946.

    The above information is only for general use, all the data and formulae may not be suitable for all engineers, plant experts, and purchasing managers. Some data may be delayed or changed and we do not assume any responsibility for any failure to notify you at the first opportunity.

    THINKTANK is a major valve manufacturer and optimal fluid solution provider, which supplies control valves, self-operated pressure regulators, butterfly valves, ball valves, eccentric plug valves, knife gate valves, globe valves, fusible link valves, and gate valves around the world. 

    Contact Us

    With expertise in valves and rich experience in the oil&gas, chemical industry, textile mills, power plants, and sugar mills. THINKTANK has become the premier manufacturer of next-generation precision control valves.

    With a customer base that includes over 42 of the world’s leading engineering&contractors and international valve brands, THINKTANK Valves offers cost-effective valves that help our customers achieve automated process control without paying high prices.

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