Ateliers Busch Sa

Ulrich Becher

Andreas Basteck

Rotary piston machine for compressible media, with rotary pistons sealed tight in a common housing and rotatable with one another in a controlled manner, the rotary pistons having a plurality of disk-shaped sections engaging in one another in pairs, whose thickness and/or diameter decreases in the direction of the pressure side, each disk having a surface area and a core area connected respectively by an interface area, the sector angles of the surface area and of the core area of a respective disk not being identical, the disks having various transverse profile contours periodically recurring along the piston axes and each disk being offset at an angle to the two adjacent disks of the same rotor in a such a way that these three disks have a common area section and form a chamber.

Rotary piston machine for compressible media

The twin screw rotors for axis-parallel installation in displacement machines for compressible media have asymmetrical transverse profiles and numbers of wraps that are &gE;2. Depending upon the wrapping angle (&agr;), the pitch (L) varies, which pitch increases in a first subdivision (T ) from the suction-side screw end, reaches a maximal value (L ) after one wrap, decreases in a second subdivision (T ) until a minimal value (L ), and is constant in a third subdivision (T ). The pitch course in the first subdivision (T ) is preferably mirror-symmetrical to that in the second subdivision (T ), within the subdivisions T to T , it is point-symmetrical to the mean values in almost all cases. Compact screw rotors, completely free of imbalance, can thereby be achieved with compression rates of 1.0 . . . 10.0, also without profile variation. Such rotors offer the best prerequisites for reduction in energy requirements, temperature, construction size, costs, as well as for free selection of working materials in applications in chemistry, pharmacy, packaging, and semiconductor technology.

Twin screw rotors and displacement machines containing the same

Displacement machines for compressible media having single-threaded, twin screw rotors with continuously decreasing pitch to achieve an inner compression are known. The demand for compact pumps with rotors as short as possible, and the frequent, process-related demand for quick disassembly of the housing, set limits however for the wrapping angle or respectively for the variation of the end profiles, which, in turn, leads to extreme pitch ratios or to insufficient compression rates. The present invention uses screw rotors with an optimized, non-monotone pitch course and alternative end profile variation with constant diameters. Suction capability is improved with the same space requirement, and compression rates of 3.0 and more are achieved easily with only four wraps. Displacement machines equipped with such twin screw rotors provide optimal results with respect to energy requirement, temperature, construction space and servicing with application possibilities in chemistry and in semiconductor technology.

Twin screw rotors for installation in displacement machines for compressible media

The displacement machine is intended in particular for use as a pump, and has a working area, formed in a housing, which working area is limited by two end walls and a casing, and is accessible via an inlet and an outlet for a working medium. At least one rotor, movably disposed in the housing, subdivides the working area, and a guide gearing for rotor control is connected to a drive apparatus located outside the working area. The invention has as its object to propose a displacement machine which can be manufactured less expensively and with less weight than known displacement machines of this type, and in particular can be operated without any special lubricant for the bearings. This object is attained in that the rotor, or respectively the rotors, is or are, supported at least partially inside the working area, and in that the bearing or bearings, disposed inside the working area, is, or are, accessible for the working medium, and is, or are, designed as rolling bearing made of ceramic materials, making possible operation of the displacement machine without lubricants. Contamination of the working medium from lubricant is thereby practically excluded.

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Porrentruy, Switzerland

Ulrich Becher