Liquid-displacement machine

The invention relates to a flow machine according to the preamble of the main claim.

In flow machines, which are subjected to a solids-containing fluid handled Risk of Erosionsverschleisses within the turbomachine. Although argument can be countered by a corresponding lining of the body, however, there is a particularly vulnerable point in the region of the shaft seal. In conveying medium solids contained, which may have a size of up to 1 mm, the shaft seal itself or the shaft seal will be able to destroy holding housing parts. Premature failure of the turbo machine would thereby given

From US-A 17 22 439 is a cartridge mechanical seal, which is flanged with the aid of a flange on a shaft passage having a housing opening, is known. The medium to be shut off from the exposed cover mechanical seal cartridge has an inlet opening, in which a pump impeller hub fits sealing. A rotating the pressure-side impeller side contains solids conveying medium would destroy the cover and then the sealing rubber bellows of the mechanical seal in the shortest time. There is also the risk that the sealing rings are destroyed due to dry running due to the lack of possibility for fluid communication within the mechanical seal.

The invention is based on the object for a flow machine, which is subjected to a solids conveying medium containing the aforementioned order to provide a measure by which a shaft seal surrounding space and the shaft seal can be protected even against erosion wear. This object is performed in accordance with the characterizing part of the main claim.

In practical tests it has surprisingly been found that an erosion wear, an erosive wear was a designed according to the main claim ring element are turned off by contained in the medium solids, up to 100 mg solids was added per dm. Dependent claims 2 and 3 indicate advantageous embodiments of the invention and the position of the free end of the annular element.

In the claims 4 to 8 described embodiments of the invention cause hazardous wear marks neither the shaft sealing even where the shaft seal surrounding space were observed. In experiments with an impeller, which was provided on the shaft seal side facing a split ring seal, the split ring seal has been damaged within a short time without the ring member. Was instead placed in the shaft sealing space receiving an inventive ring element, then even on the split ring seal no wear marks were observed after a long test period. The embodiments of claims 9 to 11 describe the various possibilities for the production of the ring element.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below. The

Figs. 1 to 3 show in this case differently shaped ring elements.

Fig. 1 shows a housing (1) of a turbomachine, which is designed here as a centrifugal pump, as well as within the housing (1) disposed impeller (2). In the embodiment selected here, the impeller suction and discharge gap ring seals (3, 4) is equipped. The impeller (2) is mounted on a shaft (5), is mounted on the further comprising a shaft sleeve (6) and constructed as a shaft seal shaft seal (7). Furthermore, the impeller (2) has in the region of the impeller hub (8) in the pressure-side impeller cover plate mounted on Axialschubausgleichsbohrungen (9).

Within the shaft seal (7) surrounding the chamber (10), here a pressure-side housing cover (11) is disposed in the housing (1) fixed ring element (12). It extends in the area between the mounted on the impeller wear ring (13) and the wheel hub (8) and the shaft seal (7). The free end of the annular element (11) has a radially extending to the shaft surface (14), pointing to the smallest diameter in the axial direction to the shaft seal (7) port (15) is mounted. The here designed as sheet-metal molding ring member (12) may also be formed as a solid molding, which would have on the side facing the shaft seal side a back rotation. Furthermore, it may be formed integrally with the housing-fixed ring gap (16).

The embodiment of FIG. 2 corresponds largely to that of FIG. 1. A difference is that the ring element (12) is provided at its free end face with a straight line extending in radial direction towards the shaft surface (14).

FIG. 3 shows a cross-sectionally frustoconical formed ring member (12) which runs diagonally to the shaft axis, with its free end face (17) facing the shaft (5). Due to the frusto-conical configuration of the ring element (12) exists at its free end face (17), as well as to the attached thereto, in Figs. 1 and 2, the smallest diameter of the surface (14) or an attached piece (15) a tear-off edge, by means of which within the space (10), an erosion wear can be prevented.