| This paper is about studies of a new type of shale shaker using a new roller-structure screen, which is made by winding the normal flat screen or corrugated pyramid screen into rotter screen, and can be installed on the shale shakers being used in the oil fieM. When the shaker is working, its roller screen not only vibrates with the shaker deck, but also slowly rotates with the axis of itself, and the drilling fluids returned from annular space are separated inside the roller screen. This kind of shaker has such features: its self-cleaning effect is powerful, no phenomena of screen pasting and screen jam happen, when improving the treating capacity by increasing throwing coefficient, the phenomena of drilling fluids spattering can be avoided, so that screening-separating drilling fluids in closed space can be realized. Hence, this new kind of shale shaker will find its application in the new drilling techniques such as under-balanced drilling. It is not a long time that the idea of this kind of shale shaker is presented, no one has done the theoretic studies and test studies on this kind of shale shaker so far. In order to clarify the working theory of a roller screen shale shaker and provide for developing this new product, the paper does some this roller screen shale shaker and has completed following studies.(1) On the basis of machinery system dynamics, the dynamics equations of balanced elliptical shakers excited by two-shaft self-synchronizing and by three-shaft self-synchronizing are established. From vibrating torque equations of shaker's exciting shafts, the self-synchronizing condition and synchronizing state stability condition of balanced elliptical shakers excited by two-shaft self-synchronizing are obtained. According to analysis dynamics theory, the self-synchronizing condition and synchronous state stability condition of balanced elliptical shakers excited by three-shaft self-synchronizing are inferred. Then the force center theories of balanced elliptical shakers excited by two-shaft self-synchronizing and by three-shaft self-synchronizing are established, which can provide theoretical foundations for designing new kinds of shale shakers.(2) Starting off with analyzing the forces affected on single dry solid granule on the roller screen, the relative slippage and slipping condition of granule at the tangential direction and axis direction of roller screen are discussed, and the average slipping conveyance velocity from feeding end to discharging end is given. The throwing conveyance of granule is discussed, the throwing coefficientof roller screen and its varying rule, and the concept of average throwing coefficient and its computing method are put forward, the starting condition and terminating condition for throwing motion of granule on the roller screen and the throwing conveyance velocity of granule are researched. The influence on throwing motion of granule by the rotating velocity of roller screen is discussed as well.(3) In terms of flowing characteristic of drilling fluids on the roller screen, the flowing equations at the axis direction and the tangent direction and the flowing through the screen, and the continuously flowing equation of drilling fluids are built. The characteristic-difference equations of flowing model for drilling fluids are given and the theoretical analysis is made.(4) The slipping conveyance model and throwing conveyance model of single wet granule are set up, in turn, computing method of velocity for slipping conveyance and throwing conveyance is given. From the phenomenon of continuously flowing for the real conveyance of wet granule group on the non-submerging roller screen, assuming the granule group as pseudo-fluid, the conveyance model of wet granule group on the non-submerging screen is established. The calculations of all conveyance models are done respectively, pared with data in tests.(5) The author has analyzed the throwing coefficient and the starting throwing condition of granule on the submergi...
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