GB956492A - Improvements relating to liquid mixing devices - Google Patents

Abstract

956,492. Agitating liquids. HAYWARD TYLER & CO. Ltd. Oct.. 5, 1962 [Oct. 25, 1961], No. 38201/61. Heading B1C. A liquid mixing device comprises an impeller 12 with vanes 20 extending along a shaft 13, the ratio of the axial length of the vanes to the diameter of the impeller being not less than 2/5 and the product of the ratio and the number of vanes being not less than 5; and means for giving the impeller a motion of rotary reciprocation through not less than 5 degrees. Preferably the ratio is 1:1 and the angle of reciprocation 15 degrees ; a convenient number of vanes being six. The vanes may be equally spaced round the shaft or grouped, and may have an attached cylindrical shroud 22A, Fig. 9, with or without an annular end shroud 23. If the impeller is completely closed at one end by a shroud as at 21, Fig. 4, the effective length of the vanes is doubled and the minimum value of the product of the ratio and the number of vanes may be 2À5. As shown in Fig. 1 the impeller shaft 13 is detachably connected at 41 to an upper part mounted in flexible bearings 32, 33 and carrying an arm 43 which is oscillated by the motor 16, eccentric 47 and link 44. If the vanes be flexible and/or the shaft flexible in torsion, and the natural frequency of oscillation of the system close to the resonant frequency, the impeller may be made to reciprocate through an angle appreciably greater than that of the arm 43. The aperture in the cover 14 through which the shaft 13 passes may be sealed by a tube 37 flexible in torsion and secured at 38, 39 to the shaft and cover respectively. The tube may have a circular or helical bellows form or may be replaced by a third flexible bearing. The axis of the shaft 13 may also be horizontal or inclined.