[Details] How to select the applicable model according to the classification of pneumatic butterfly valves?
Pneumatic butterfly valve is an ideal vibration isolation element. As a kind of vibration isolation element with adjustable nonlinear static and dynamic stiffness and damping, pneumatic butterfly valve is used more and more widely. Today, I will give a detailed explanation on the classification of pneumatic butterfly valves
At present, the classification methods of pneumatic butterfly valves at home and abroad are very different, which are roughly as follows:
（1） Classification according to the number of curvature of cysts
Pneumatic butterfly valves are divided into single (1), double (2), three (3),......, n curves according to the number of curves of the capsule, as shown in Figure 1-3 and Figure 1-4. With the increase of curvature, the stiffness becomes smaller, and the natural frequency of the pneumatic butterfly valve vibration isolation system also decreases accordingly. However, this not only brings trouble to the manufacturing, but also causes the elastic instability of the capsule, so generally only 4 coils are used.
（2） Classification by structure type
1. Classification in German Pneumatic Butterfly Valve:
Capsule pneumatic butterfly valve: tire type [Figure 1-3 C]
Flat type [Figure 1-3 A, B
Earlobe type [Fig. 1-4 B]
2. Classification of China:
Pneumatic butterfly valve: 1. Bag type pneumatic butterfly valve [Fig. 1-2, 1-3]
2. Restraining diaphragm pneumatic butterfly valve [Fig. 1-4 A]
3. Free diaphragm pneumatic butterfly valve [Fig. 1-4 B]
other
Bag type pneumatic butterfly valve The bag type pneumatic butterfly valve is a lantern shaped structure made of membrane, which can be one section or several sections connected in series, and is called single curve, double curve or multi curve bag type pneumatic butterfly valve respectively. Metal rims are embedded between each section to bear the effect of internal pressure and tension.
Diaphragm pneumatic butterfly valve: the structure of the diaphragm pneumatic butterfly valve is to place a membrane between the metal outer cylinder and the inner cylinder, or between the cylinder cylinder and the piston, and realize the overall expansion and contraction through the deformation of the membrane. Appropriate inclination or curved surface shall be given in advance on the inner wall of the outer cylinder and the outer wall of the inner cylinder, according to which the membrane can deform along the wall when it expands and contracts, and the pressure area changes with the deformation. This enables us to obtain the properties that are very soft at the rated height but become hard at large displacement, that is, proper nonlinear elasticity. The membrane pneumatic butterfly valve is divided into the confined membrane type and the free membrane type.
（3） Classification according to whether the angle changes
1. The pneumatic butterfly valve with only the internal angle changed and the external angle unchanged is called the internal angle modified pneumatic butterfly valve;
2. The pneumatic butterfly valve with only the outer angle changed and the inner angle unchanged is called the outer angle modified pneumatic butterfly valve;
3. The pneumatic butterfly valve whose internal and external angles change is called double angle changing pneumatic butterfly valve;
4. The pneumatic butterfly valve whose internal and external angles do not change is called the constant angle pneumatic butterfly valve.
Figure 1-3 Bag type pneumatic butterfly valve bag model
A double curve, B triple curve, C single curve