WCB CF8 CF8M Pneumatic Diaphragm Type Pressure Regulating Control
Valve With Positioner
Product introduction:
Pneumatic precision diaphragm control valve also known as
regulating valves, which including: SZJHP pneumatic precision
diaphragm single seat regulating valve, SZJHM pneumatic precision
diaphragm sleeve regulating valve and SZJHN pneumatic precision
diaphragm double seat regulating valve, which adopts a top guide
structure and is equipped with a multi spring actuator. It has the
advantages of compact structure, light weight, sensitive action,
S-shaped fluid channel, small pressure drop loss, large valve
capacity, accurate flow characteristics, and convenient disassembly
and assembly. Widely used for precise control of process parameters
such as pressure, flow rate, and liquid level in gases, liquids,
and other media to maintain a given value. Especially suitable for
working situations where small leakage is allowed and the pressure
difference between the front and back of the valve is not
significant.
There are various types of pneumatic precision diaphragm regulating
valves, including standard type, regulating cut-off type, pipe
sealing type, jacket insulation type, etc. The nominal pressure
rating of the product includes PN16, 40, and 64; The nominal
diameter range is DN20-300. Suitable for various liquid
temperatures ranging from -200 ℃ to+560 ℃. The leakage rate
standard has level IV or VI, and the flow characteristics are
linear or equal percentage
Product technical parameter:
Port size DN(mm)
(Core diameter dn) | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 125 | 150 | 200 | 250 | 300 |
| (10) | (12) | (15) | (20) |
| Rate flow coefficient Kv | Linear | 1.8 | 2.8 | 4.4 | 6.9 | 11 | 17.6 | 27.5 | 44 | 69 | 110 | 176 | 275 | 440 | 690 | 1100 | 1760 |
| Equal percentage | 1.6 | 2.5 | 4.0 | 6.3 | 10 | 16 | 25 | 40 | 63 | 100 | 160 | 250 | 400 | 630 | 1000 | 1600 |
| Rate stroke(mm) | 10 | 16 | 25 | 40 | 60 | 100 |
| Effective area of membrane Ae(cm2) | 280 | 400 | 600 | 1000 | 1600 |
| Signal range Pr(KPa) | 20～100,40～200 |
| Air source pressure Ps(KPa) | 0.14～0.4 |
| Inherent flow characteristics | Linear and equal percentage |
| Inherently adjustable ratio R | 50:1 |
| Allowable leakage | Hard seat:ⅣClass; Soft seat: Ⅵ Class |
| Pressure nominal PN(MPa) | 1.6, 4.0, 6.4 |
Working temperature T
(℃) | Normal temperature | -20～200,-40～250,-60～250 |
| Heat dissipation | -40～450,-60～450 |
| High temperature | 450～560 |
| Low temperature | -60～-100,-100～-200,-200～-250 |
Product features:
1. The input-output characteristics of the actuator of the
pneumatic diaphragm control valve show a linear relationship, that
is, there is a linear relationship between the output displacement
and the input signal pressure. The output displacement is called
the stroke and is displayed on the stroke display board. Some
reaction actuators also install valve position displays on the
upper part of the capsule to display the valve position. There are
six specifications for the stroke of domestic pneumatic diaphragm
control valve actuators, including 10mm, 16mm, 25mm, 40mm, 60mm,
and 100mm.
2. The effective area of the diaphragm of the actuator is directly
proportional to the thrust, and the larger the effective area, the
greater the thrust of the actuator.
3. The structure of the positive and negative action actuators is
basically the same, consisting of an upper diaphragm cover, a lower
diaphragm cover, a membrane membrane, a push rod, a spring,
adjusting components, a bracket, and a stroke display board.
4. The main difference between the structure of positive and
negative action actuators is that the input signal of the negative
action actuator is located at the lower part of the diaphragm box,
and the outgoing push rod is also located at the lower part. Due to
the good sealing of the diaphragm, there is no need to seal at the
outlet of the valve stem.
5. The initial force of the spring can be changed by adjusting the
adjusting element, thereby changing the thrust of the actuator.
6. The pneumatic diaphragm control valve can be equipped with a
self-locking device to achieve self-locking and positioning of the
control valve.
7. Valve positioners can be added to achieve valve position
detection and feedback, improving control performance.
8. A displacement conversion device can be added to the pneumatic
diaphragm control valve to convert linear displacement into angular
displacement, which is used to rotate the valve body.
9. The pneumatic diaphragm control valve can be equipped with a
hand-wheel mechanism, which can be used for degradation operation
in case of automatic control failure, improving system reliability.
