Georg Fischer 578 Specifications

GF Piping Systems

Lug Style Butterfly Valve

Type 578

General

The Type 578 Lug Butterfly Valve has several beneficial design
features unique to the Georg Fischer butterfly valve line. The
double eccentric operating principle has an o-center disc and
shaft that disengages the disk from the seal with only 3
degrees of rotation. This significantly reduces component
wear and required operating torque, as the disk is not in
contact with the seal when the valve is opening and closing.
Conversely, a traditional boot-style valve has a centric design,
significantly increasing the required operating torque because
of the disk sealing principle associated with these valves.
Boot-style valves often show a far more dramatic increase in
required operating toque over time than a double eccentric
valve. This can result in premature actuator failure and can
even render the valve inoperable. Georg Fischer double
eccentric butterfly valves require approximately 50% less
operating torque than boot-style competitive valves.

The 578 valve also features a truly non-wetted shaft design.
The bushing assembly has a double O-ring seal on both the
disk and body sides, providing the highest level of protection
and reliability.

Features

• Size: 2”–12”

• Body: Glass filled PP with overmolded SS316 lugs,
ANSI 150 bolt pattern

• Materials: PVC, CPVC, PP and PVDF

• Stem: 316 stainless steel

• Seal: EPDM or FPM; PTFE seals available upon request

• Operation: Bare shaft, lever, gear

Optional Features

• Actuation: Electric, pneumatic

• Accessories:

• Integrated electrical feedback

• Handle extension

• Chain operator

• Square operating nut

• Fine adjustment lever (1 degree)

Technical Data

180

165

150

135

120

105

90

75

60

45

30

15

0

-50 -30 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

temperature in °C

permissible pressure in psi

ABS, PVC, CPVC

(useful life 25 years; medium water)

CPVC

ABS

PVC

Y (psi)

Pressure-temperature diagrams

PP, PVDF (useful life 25 years; medium water)

180

165

150

135

120

105

90

75

60

45

30

15

0

permissible pressure in psi

temperature in °C

ABS, PVC, CPVC

180

165

150

135

120

105

90

75

60

45

30

15

0

permissible pressure in psi

temperature in °C

ABS

PP

(useful life 25 years; medium water)

CPVC

PVC

PVDF

Flow characteristics

100

90

80

70

60

50

40

kv value (%)

30

20

10

0

0102030405060708090 100

opening angle (%)

Pressure loss

DN 50 / 2"

DN 65 / 2½"

X (US gal./min)

DN 100 / 4"

DN 80 / 3"

X (l/min)

DN 125 / 5"

DN 150 / 6"

DN 250 / 10"

DN 200 / 8"

DN 300 / 12"

2.64 26.4 264.2 2642
1

0.1

Y (bar)

0.01

0.001

Operating torque

14.5

1.45

0.145

0.0145

000001000010001001

P0737409

Cv values

DN mm Inch d mm Cv 100 gal/min

(Δp = 1 psi)

50 2 63 103
65 2½ 75 154
80 3 90 210
100 4 110 455
125 5 140 805
150 6 160 1162
200 8 225 2772
250 10 280 3570
300 12 315 5110

2

For non-GF actuators, breakaway torques 2.5 to 4 times the value of the
moving torque must be taken into consideration, depending on the
application conditions (e.g. control time, medium, temperature, etc.).