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valves and accessories
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AREA OF PIPE
Pipe Size
(Sch 40) Area
In./mm Sq. ft/Sq. cm
14 0.940
350 873.29
16 1.227
400 1,140
18 1.553
450 1,443
20 1.931
500 1,794
24 2.792
600 2,594
SERIES 8000GR
Butterfy Valve
Torque is the rotary effort required to operate a value. This turning force
in a butterfy valve is determined by three factors; the friction of the disc
and seat due to interference for sealing, bearing friction, and fuid dynamic
torque.
Breakaway torque is the total of the torques resulting from bearing friction
and disc/seat interference friction at a given pressure differential. This
value is normally the highest required torque to operate a valve, and is used
to size the actuator. Listed below are recommended sizing torques.
NOTE: These values are based on testing performed in the Gruvlok Research
& Development Center. These values include a safety factor and are valid for
water and lubricating fuids only at 70° F (21° C).
Since torques are greatly increased for dry and non-lubricating fuids and
temperature variations, contact your Gruvlok Sales Offce for accurate
values in these applications.
NOTE: For Tefon seated valves, contact your Gruvlok Sales Offce.
These values are valid for water and lubricating fuid service only.
Contact factory for information on torques for dry and non-lubricating fuid service.
Fluid Dynamic Torque is the force
exerted when a fuid passes over
the surface of the butterfy valve
disc. The magnitude of this force
is dependent on valve size, disc
opening and fow through the
valve. Typically, fuid dynamic
torque is a maximum at an
approximate 75° disc opening.
Generally, the effects of dynamic
torque can be ignored when the
velocity is less than 15 feet/second
for liquids and 15,000 feet/minute
for gases to minimize the effects
of turbulence on the valve. For
applications above these limits,
consult engineering.
The formula for determining the velocity for liquids is:
The formula for determining the velocity of gases:
* Flowing condition means at temperature and pressure of gas stream in
the valve
V = 0.0022
V = Velocity of liquid (feet/second)
Q = Flow (gallons/minute)
A = Area of upstream pipe (sq. ft.)
See “Area of Pipe” chart
Q
A
Vg =
Vg = Velocity of gas (feet/minute)
Qf = Flow of gas @ fowing condition*
(cubic feet/minute)
A = Area of upstream pipe (sq. ft.)
See “Area of Pipe” Chart
Qf
A
ACTUATOR SIZING FOR GENERAL SERVICE APPLICATION
SERIES 8000GR BREAKAWAY TORQUE
Line
Pressure
Valve Size (In.)
14 16 18 20 24
(PSI)/Bar Breakaway Torque (In. - Lbs.) / N-m
50 4,000 4,800 5,400 10,000 13,000
3.4 452 542 610 1,130 1,469
100 4,800 5,200 6,200 12,500 18,000
6.9 542 588 701 1,412 2,034
150 5,500 6,500 8,500 13,500 21,500
10.3 621 734 960 1,525 2,429
CV VALUES (WATER @ 70°F SP. GR. = 1.00)
Valve Size
Disc Position (Degrees Open)
25° 30° 40° 50° 60° 70° 80° 90°
In./mm
14 650 825 1,500 2,300 3,500 6,200 9,700 10,500
350 44.8 56.9 103.4 158.6 241.3 427.5 668.8 723.9
16 850 1,000 1,850 2,900 4,600 7,500 10,600 13,500
400 58.6 68.9 127.6 199.9 317.2 517.1 730.8 930.8
18 1,100 1,400 2,450 3,800 5,000 9,700 13,850 18,000
450 75.8 96.5 168.9 262.0 344.7 668.8 954.9 1,241.1
20 1,400 1,650 3,050 4,800 7,400 12,500 17,750 23,000
500 96.5 113.8 210.3 330.9 510.2 861.8 1,223.8 1,585.8
24 2,000 2,400 4,200 6,600 10,500 17,000 23,000 31,000
600 137.9 165.5 289.6 455.1 723.9 1,172.1 1,585.8 2,137.4
GL-2.10