sieve shaker,cement testing machine

A sieve shaker for screening material such as ore or coal wherein the sieve member extends horizontally and is supported at its edges by longitudinal sidewalls and at the center by a longitudinal intermediate wall and a vibratory oscillatory drive force is applied to the intermediate wall twice that of the sidewalls by rotating eccentric weights for the intermediate wall and sidewalls with the intermediate wall eccentric weight being twice that of the sidewalls eccentric weights and the rotating weights interconnected by flexible shaft drives and a main drive motor driving all of the weights in rotation.cement testing machine.
Oscillating or shaking sieves are used in ore and coal preparation installations. For continuous effective operation, and in order to handle large volumes of ore and coal, it is necessary to continuously drive the screen or sieve structure in vibration or oscillation. One form of generating the oscillating drive force is by the rotation of eccentric or unbalanced weights wherein the force from the rotation of the unbalanced weights is transmitted to the sieve surface. For satisfactory operation, it is desired that the vibratory forces are distributed as uniformly as possible over the entire sieve surface. This permits feeding the ore or coal uniformly to the surface, and results in uniform screening as the material passes over the surface. Unequal vibration results in unequal screening, and attempts to compensate for such unequal vibration are difficult because feeding the material to the screen normally is done at a uniform rate, and unequal screening is almost sure to occur if unequal vibration exists across the screen.soil testing apparatus.

If the sieve shaker construction is made narrow, it is more easy to rigidify the construction to obtain uniform vibration over the width of the screen surface. However, for production of coal and ore plants, it is commercially and economically necessary to provide relatively wide sieves which have a high through-put capacity. This in turn creates problems of obtaining rigidity of the sieve for purposes of attempting to obtain uniform vibration or oscillation across the entire width of the sieve surface.

It is accordingly an object of the invention to provide an improved construction for obtaining uniform oscillation or vibration across the width of a sieve surface making it possible to use relatively wide sieves and eliminating the necessity of very heavy constructions which are made heavy to rigidify the sieve to attempt to obtain the same vibration or oscillation in the center of the sieve as occurs at the edges. This objective is accomplished by an improved support and drive arrangement which obtains substantially uniform vibration across the width of the sieve. By eliminating heavy rigidifying constructions, the cost of sieve shaker construction is reduced, and the input power needed for the vibratory drive can be relatively reduced.