Abstract: Mixer apparatus having an impeller on a shaft, which circulates a body of liquid the surface of which can clear the impeller, especially when the liquid is in a tank, and the tank is drained, is protected against excessive by use of a flexural member, which may be in the form of radially opposed pairs of resilient plates, which extend from the shaft and are attached thereto by a collar. As the liquid surface drops below the impeller, the members present surfaces to the liquid in the tank on which forces are opposing the oscillation are developed by interaction of the surfaces with the liquid in the tank. Restoring forces on the shaft due to the flexing of the resilient plates also reduce the shaft oscillation. The stiffness of the plates is selected to optimize the restoring forces for the mixing apparatus which is stabilized.

Abstract: A method for making an end connection for a shaft made of composite material, which accommodates for differences in stiffness, thermal expansion, and chemical resistance between the shaft and the member connected thereto and operates under oscillating torque, thrust, and bending loads, and also provides for manufacturing flexibility in enabling the shaft and connection to be produced as separate parts which are formed when final assembly is to occur. The connection has a male insert which is inserted into the end of the composite shaft. Axial and circumferential grooves are cut in the surfaces of the male insert and the shaft. These grooves are aligned to form circumferential and axial keyways which intersect each other. Material is injected into the keyway and polymerizes to form structural keys which transmit the thrust and torque, while locking the insert member and the shaft permanently together.

Abstract: An end connection for a shaft made of composite material, which accommodates for differences in stiffness, thermal expansion, chemical resistance between the shaft and the member connected thereto and operates under oscillating torque, thrust, and bending loads, and also provides for manufacturing flexibility in enabling the shaft and connection to be produced as separate parts which are formed when final assembly is to occur. The connection has a male insert which is inserted into the end of the composite shaft. Axial and circumferential grooves in the surfaces of the male insert and the shaft. These grooves are aligned to form circumferential and axial keyways which intersect each other. Material is injected into the keyway and polymerizes to form structural keys which transmit the thrust and torque, while locking the insert member and the shaft permanently together. The bending loads are transmitted through the tight fit extending axially between the shaft, insert member and keys.

Abstract: Apparatus for mixing liquid and liquid suspension mediums in vessels with a mixing impeller shaft system of a composite of fibrous and plastic material of a structural configuration to enable the use of such material in commercial and industrial applications where the reaction loads of the medium on the system militate against the use of composite fibrous and plastic material. The system utilizes impellers having blades which distribute the reaction load through a hub on a mounting area of a shaft with keys and keyways in a manner to avoid stress risers unamicable to the composite material and which can cause failure thereof. Separate keys and keyways are provided to oppose the thrust due to the reaction loads and to oppose the torque due to such loads. Plural thrust keyways may be used to enable the impeller to be located at different positions on the shaft and at selected heights above the floor of the mixing vessel.

Abstract: Mixing systems for liquids having fibers suspended therein wherein the fibers tenaciously adhere to and accumulate on the leading edge of the impeller, thereby increasing the drag of the liquid on the impeller as it rotates and the consequent increase in the power required to rotate the impeller. Axial flow of the liquid in a tank is produced by the impeller within a draft tube. The leading edge of the blades of the impeller are inclined with respect to radial lines extending from the axis of rotation of the impeller beyond the angle of repose of the fibers on the leading edge. Also, the coefficient of friction of the portion of the impeller, extending from the leading edge toward the trailing edge thereof, to which the fibers adhere is reduced by providing the surface thereof with a low coefficient of friction material.