www.pavo.ch 42 The screen mountings are designed specifically to meet the requirements for free oscillating screens ▪ Due to the specific geometry, the vibration forces are deflected and, despite a low overall height and small spring deflections, a small natural frequency and thus a high degree of isolation and low residual force transfer into the structure are achieved. ▪ The low overall height and the combination of the various degrees of stiffness in the individual components ensure a laterally stable guidance of the screen without restricting the oscillation movement in the main oscillation direction. ▪ This product group, where it was possible for strength-related aspects, was consciously built with aluminum components. A portion of the screen mounting is a resonant mass, which must be excited by the drive. For example, in a weight-reduced design of the screen mounting, the energy is available for better conveying. Where steel parts are required, the lever has been reduced by the two-sided arrangement and the stabilization is nevertheless increased and the stress peaks reduced, which gives a good service life time. ▪ Although the screen mountings in many plants are often not seen after a short time due to soiling, the visible rust formation is an undesirable phenomenon. The non-painted aluminum parts are corrosion-resistant and the steel parts are coated with a shock-proof powder coating. In the case of customer-specific screen mountings, the individual colors allow for the matching with the corporate identity of the customer. ▪ The contours, which extend transversely to the element axis, are not only an optical feature. Since there are only a few horizontal surfaces, the locations where material can be fixed are reduced and cleaning is facilitated. ▪ Above all, in the case of the large types and a large number, the rubber bodies are exchanged after the end of the service life time. The levers can be easily disassembled on the plant side by their own maintenance and only the light aluminum components reach the return. With the reduction of weight and volume, an ecological and economic transport can be achieved. The 4 main types of free oscillating screens ▪ In practice, there is a wide variety of different screening machines. Nevertheless, four main groups can be defined. This results in various requirements for the screen mounting, which can be the only one in a screening group. On the other hand, the performance properties of a screen mounting are suitable for different screen groups. Circular-Screen machine The almost circular shape of the oscillating motion gives the screen machine the name. Depending on the position of the center of gravity of the oscillating mass to the point of the force of the unbalance, the oscillation shape varies. The feeding is provided by the inclination up to 30 °. The Screen Mounting Type SM-U is specifically suitable for belt drive systems or adjustable screens. The Screen Mounting Type SM-P is specifically designed for systems with a cardan drive and spontaneous loading. Linear-Screen machine The linear oscillating motion gives the screen the name. Depending on the position of the center of gravity of the oscillating mass to the point of the force of the unbalance, the oscillation shape varies. The feeding results by the impact direction angle. The Screen Mounting Type SM-U is specifically designed for belt drive applications. The Screen Mounting Type SM-P is specifically designed for systems with a cardan drive and spontaneous loading. The Screen Mounting Type SM-F is specifically designed for smaller amplitudes peak to peak and low overall height. Two-mass free oscillating screen machine with a counter mass The Screen Mounting Type SM-U is specifically suitable for the screen box because of the low natural frequency. The Screen Mounting Type SM-F is specifically designed for the counter-mass. One-mass hanging linear screen machine The oscillating mass is suspended from the structure. The Screen Mounting Type SM-H is specifically designed for hanging screens.