Emission Free Bellows Seal Valves

Below are typical arrangements of Bellows Sealed valve designs featuring a standard flanged joint arrangement for easy access for maintenance and component replacement and a fully welded bonnet assembly for those really difficult services or where customers want to use butt welded pipework and fitting.

Standard construction:

a) Top Guide Bush
b) Secondary Stem Seal
c) Test Point
d) Gasket Joint
e) Valve Stem
f) Primary Bellows Seal
g) Extended Bonnet/Cooling Fin
h) Bottom Guide Bush
i) Valve Body

Fully welded construction:

a) Secondary Stem Seal
b) Seal Welding
c) Top Guide Bush
d) Long Thread Engagement for Strength
e) Valve Stem
f) Primary Bellows Seal
g) Extended Bonnet / Cooling Finv
h) Bottom Guide Bush
i) Valve Body

Product Ranges

  • Process Control Valves
  • Two Way Valves
  • Three Way Valves
  • Fluid Control
  • Globe Valve
  • Temperature Control
  • Actuators
  • Process Instruments
  • Severe Service Valves
  • Pneumatic Actuator
  • Electric Actuators
  • I/P Transducer
  • Bellows Seal
  • Heating & Ventilation
  • Steam Valve
  • Water Valve
  • Safety Valves
  • Pressure Regulating Valves
  • Pressure Reducing Valves
  • Strainers
  • Butterfly Valves
  • Flow Regulators
  • Manifolds
  • Din Valves
  • Ansi Valves
  • Bellow Steam Seals
  • Low Noise Trims
  • Valve Repairs

Control Characteristics

Emission Free Bellows Seal Valves – Control Characteristics

The basic characteristic is equal percentage but the Paragon trim greatly extends the control capability at valve plug lifts up to 50% of full travel. See the shaded area in the graphic to the right.

Kv Values
Flow Capacity Kv
Valve Size (mm)
15
20
25
40
50
65
80
100
150
Trim A
3.5
6.4
10.0
24.0
34.0
62.0
100
160
330
Trim B
1.5
1.5
6.4
6.4
10.0
24.0
62
100
160
Trim C
–
–
1.5
1.5
6.4
10.0
38
62
100
Differential Pressures, Flow-to-open, Spring-to-close (AFC)
Valve Shut-off Capability (Barg)
Valve Size (mm)
15
20
25
40
50
65
80
100
150
250 Actuator (3 Barg)
48
48
48
20
15
6
–
–
–
500 Actuator (3.5 Barg)
–
–
–
–
–
18
12.0
7.5
3.0
Differential Pressures, Flow-to-open, Sprint-to-open (AFO)
Valve Shut-off Capability (Barg)
Valve Size (mm)
15
20
25
40
50
65
80
100
150
STD. Actuator
250cm2
500cm2
Actuator Supply
3 Bar AIR
48
48
48
–
–
–
–
–
–
4 Bar AIR
48
48
48
18
11
6.8
5.1
3.1
1.2
5 Bar AIR
48
48
48
36
22
13.5
14.5
9.2
3.9
6 Bar AIR
48
48
48
48
33
20.3
24.0
15.2
6.7
Differential Pressures, Flow-to-close, Spring-to-close (AFC)
Valve Shut-off Capability (Barg)

N.B. All differential pressures are maximum values for ANSI Class 300 and will need to be derated for other body ratings.

For further information about optional trim sizes, actuator combinations and spring rates please consult out Techincal Sales Department.
Valve Size (mm)
80
100
150
STD. Actuator
500cm2
Actuator Supply
4 Bar AIR
5.7
3.3
1.2
5 Bar AIR
16.2
9.8
4.1
6 Bar AIR
26.6
16.2
6.8

Contact us with any enquiries and we will be happy to help.

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