Abstract: The gas entrainer is a rotodynamic machine for trapping and dispersing bubbles of air into a pool of water. A flat circular disc is mounted for rotation close to and concentric with one end of an open cylindrical tube of equal diameter to form an annular nozzle therebetween. Upon the disc and tube end being immersed in water, the spinning disc draws air down the tube and out through the nozzle to disperse it as fine bubbles into the pool. The faster the disc is spun, the more air bubbles are produced; and this at a considerable depth of water. The disc or rotor employed is without blades or paddles and accomplishes entrainment simply by viscous friction between the disc and water in combination with the closely spaced tube end.

Abstract: A rubber bellows type seal (23) for reciprocating motion having an improved stroke to length ratio is obtained by fully separating the annular rubber convolutions (30) by axial deflection spaces (31,32) to allow the convolutions to be freely deflected in both directions This double deflection gives the bellows an increased stroke and thus an increased stroke to length ratio. Inner and outer tubular elements (25, 28) are bonded to the convolutions to support them in spaced apart working relationship.

Abstract: A mechanical duty bellows seal is constructed from a number of annular rubber diaphragms of comparatively thick cross-section alternately bonded to a series of outer and inner metal hoops so that the hoops hold the rubber diaphragms in simple shear during flexure of the bellows. The stresses in the rubber in shear are predictable thus allowing the calculation of diaphragm proportions to control stress levels.