LW.A / Vibration-damping Levelling Elements, Steel Base and Stem
Features
ELESA vibration-damping levelling elements have been designed to damp vibrations, shocks and noises produced by moving bodies or non-balanced vibrating masses of equipment and machines which can cause:
- malfunctioning and reduction of the machine lifespan and/or of the adjacent ones;
- damage to operator's health;
- noise.
Material
Base
Zinc-plated steel.
Damping Element
NR rubber, hardness 80 Shore A, black colour, matte finish.
Levelling Plate
Zinc-plated steel.
Packing Ring
NBR synthetic rubber O-Ring.
Threaded Stem
Zinc-plated steel, supplied not assembled.
Nut and Washer
Zinc-plated steel.
Specifications
1. Basic data required:
- disturbing frequency: the frequency of the disturbing vibration produced by a on-duty machine. In general, it is obtained by the number of rotations of the engine [Hz=r.p.m./60];
- the load applied to every single vibration-damping element [N];
- the isolation degree required [%];
- the deflection value of the vibration-damping element under a given load [mm];
- the rigidity, that is to say the load that applied to the vibration-damping element produces a deflection of 1.0 mm [N/mm].
2. How to choose the vibration-damping element:
- with reference to the diagram for checking the isolation degree, intersect the disturbing frequency value with the isolation degree required (each isolation degree corresponds to a line in the diagram) and define the deflection [in mm];
- divide the load applied onto the vibration-damping element by the deflection value to obtain the required rigidity of the vibration-damping element;
- compare the rigidity obtained with the rigidity shown in the table and choose the vibration-damping element which presents the nearest value (lower) to the calculated one.
3. Check:
- the deflection of the vibration-damping element chosen can be obtained in the graph on the basis of the load;
- intersect the disturbing frequency value with the vibration-damping element deflection value in the diagram to obtain the isolation degree offered by the vibration-damping element chosen;
- compare the obtained value with the isolation degree required.
4. Example:
Conditions of use: disturbing frequency = 50 Hz (3,000 r.p.m.); load applied to every levelling element = 4,000 N; a 80% isolation degree is required;
- diagram shows that with a 50 Hz disturbing frequency and an isolation degree of 80%, the deflection obtained is 0.6 mm;
- divide the load applied by the deflection obtained to define the rigidity required, which is 4,000/0.6= 6,666 N/mm;
- compare the rigidity value obtained (6,666 N/mm) with the values reported in the table. This value is within the rigidity value reported in the table for LW.A-120 (4,000 N/mm) and LW.A-160 (9,000 N/mm). Choose the vibration-damping element with the lower value that is LW.A-120.
For a further check:
- graph shows that LW.A-120 (4,000 N/mm) deflection is 1mm.
- by intersecting the deflection value with the disturbing frequency of 50 Hz in the diagram, the isolation degree obtained is 90%.
This value is even greater than the required one; your choice has proved to be correct.