Abstract: A helical gear pump, compressor or motor including an inner member with an external helical gear form having n starts, an outer member with a cooperating internal gear form having n.+-.1 starts. The inner member is provided with a first externally toothed gear and the outer member is provided with a second externally toothed gear. A geared connection between the first and second external gears synchronizes the rotation of the inner and outer members so that they can rotate relative to one another independently of any contact between the helical gear forms of the inner and outer members.

Abstract: A method and apparatus for producing a cellular product, such as cellular chocolate, in which the first component of the product, e.g. the chocolate, in liquid form, has introduced into it a second gaseous component which is largely soluble in the liquid first component, the gas is dispersed in the first liquid component uniformly so that it is dissolved throughout the liquid, the pressure is released suddenly, so that the dissolved component forms gaseous bubbles in the liquid and the first component in the resulting product is then solidified by cooling.

Abstract: A joint for jointing the ends of two pipes, particularly lined pipes, in which a radial resilient portion extends between the two ends of the pipes, two oppositely extending axial portions at the radial inner part of the radial portion each engage within the interior of one of the two pipe ends. Construction of the joint is such that the axially extending portions of the joint are urged radially outwardly against the inner surface of the two pipe ends as the two pipe ends are drawn axially towards one another.

Abstract: A mixing device of the type having a housing of generally cylindrical construction, having an end wall with concentric arrays of axially extending mixing elements thereon, a rotor being rotatable within the housing and having on the face thereof further axially extending mixing elements in a plurality of annular concentric arrays, the mixing elements of the rotor and housing interfitting with one another. The mixing elements themselves are each defined by inner and outer part-cylindrical surfaces and by further straight surfaces forming the sides of grooves, the axes of the grooves being disposed along different tangents to an inner pitch circle which is concentric with the part-cylindrical surfaces. This provides a much better mixing effect and produces a certain reverse pumping within the mixer. These features enable the mixing elements to be made shorter with the possibility of the rotors and end walls of the housing being formed by moulding.

Abstract: An in-line mixer for mixing fluids pumped along a tube, being a number of mixing elements inserted in series longitudinally along a tube, each mixing element comprising a plate member folded along at least one fold line to form at least two substantially planar portions angled with respect to one another, at least one of the planar portions being of triangular shape having a base edge extending across the tube, substantially centrally thereof from one side to the other of the tube, the at least one fold line forming another side of said triangular portion.