Vibrating screen includes circular vibrating screen, linear vibrating screen and resonance screen, among which the former two are commonly referred to as inertial vibrating screen. Although they are different in working principle and structure, they all have the same main components, namely, vibrator, screen box, transmission device and vibration isolation device.
- The latter can simplify the structure of vibrating screen, make it easy to manufacture and have a long service life, so it has been widely used in practice. The linear vibrating screen has two types of vibrators: box type and barrel type. However, some new vibrators can make the vibrating screen move in a straight line or a circle as long as they are slightly adjusted in structure, which can be called dual-use vibrators. The resonance screen is composed of two nearly equal vibration masses. These vibrators will be detailed below.
- The screen surface and its fastening device have been described previously. The box frame is composed of side plate and cross beam, the side plate is made of 6~16mm thick steel plate, and the cross beam is made of steel pipe, channel steel or I-beam; They can be connected by riveting, welding or high-strength bolts. The manufacturing process of riveted structure is complex, but it has good adaptability to vibration load. The welding structure process is simple, but the welding seam is complex and the internal stress is large.When the welding seam is subjected to strong vibration, it is easy to crack, and even cause component fracture; Therefore, tempering treatment can be used to eliminate internal stress. Generally speaking, the welding structure is suitable for small and medium-sized vibrating screens,High strength bolts and ring grooved rivets are suitable for large vibrating screens because of their reliable connection and ease of on-site screen frame assembly.
- Driving device Vibrating screen generally adopts V-belt driving device, which is simple in structure, and the speed of the vibrator can be selected at will, but the belt is easy to slip during operation, resulting in screen hole blockage. Some directly drive the shale shaker with the coupling, which can keep the rotating speed of the vibrator stable and prolong its service life, but cannot adjust the rotating speed of the vibrator. At present, high-performance gear transmission system is also used.
- Vibration isolation device The commonly used vibration isolation devices of vibrating screen include coil spring, plate spring and rubber spring. The coil spring is compact in structure and small in overall dimension, and the obtained stiffness is very small, with good vibration attenuation performance. It does not need fasteners and works reliably; But the disadvantage is that the lateral stiffness is small, and the sieve is prone to transverse vibration.
The advantages of plate spring are large transverse stiffness, which can eliminate transverse vibration. The disadvantages are large overall dimensions, difficult installation, and many breaking accidents. The advantage of rubber spring is that it has small overall dimension, but it has large stiffness, and its good vibration isolation performance is not suitable for large amplitude and large dynamic load. Because of the large amplitude of the vibrating screen, cylindrical spiral spring is generally used as the vibration isolation device.