Rotary vane feeder with a sealing arrangement between the cell-wheel side panel and the associated bearing cap

(42) Date of commencement of the patent: 15. 3.1998 (45) Date of issue: 25.11.1998 (51) Int.Cl.⁶ : B65G 53/46 (62) Excretion from application No: 1309/91

<td>(30) Priority:</td><td>(73) Patent owner:</td>

<td>26. 4.1991 DE 4113738 claims.</td><td>WAESCHLE MASCHINENFABRIK OCH 0-88214 RAVENSBURG (DE).</td>

<td>(56) Documents:</td><td></td>

<td>DO 260687A GB 415011A</td><td></td>

(54) CELL WHEEL SLAB HIT OF A SEAL ASSEMBLY ASSOCIATED BEARING COVER

BETWEEN THE CELL WHEEL SIDE DISC AND THE (57) In a rotary valve, a low-wear sealing arrangement between the side windows of its cellular wheel and the respective bearing caps of its housing can be realized by providing a packing ring (7c) of deformable sealing material between each bearing cover (5a) and the respective side window (5). 4a) is arranged floating and loaded by a spring-loaded metal profile ring (8e) in the axial direction.

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CQ

AT 404 352

BSReeraaß

AT 404 352 Β

The invention relates to a rotary valve specified in the preamble of claim 1

Art.

As a sealing arrangement between each side window and the associated bearing cover of the housing is a from the bearing cover side against the bearing cap that facing end face of the relevant side plate elastically pressed sliding ring known. However, the sliding ring is subjected to unavoidable wear, which is the higher, the more strongly the sliding ring is pressed against the end face of the side window. The necessary contact pressure must be higher, the greater the pressure difference between the inlet and the outlet side of the lock. Furthermore, it is difficult to realize with such a sliding ring - seen in the flow direction - long sealing gap, which would be desirable in itself, since the sealing effect is the better, the longer (and the narrower) the sealing gap. However, a corresponding widening of the slide ring is contrary to the fact that the risk of uneven wear with increasing width of the slide ring is greater.

The invention has for its object to provide a rotary valve specified in the preamble of claim 1 type with an improved seal assembly, which is subject to only minor wear. This object is achieved by the features specified in the characterizing part of claim 1.

By proposed in the context of this solution, to the axis of the cellular wheel coaxial metal ring on the adjacent bearing cap facing end face of each side window of the cellular wheel, a long flow path is created. In this flow path, the filler ring is now arranged, which is stationary relative to the metal ring and requires only small axial pressure forces, which are generated by means of the spring arrangement. The filler ring is therefore largely free of forces and therefore subject to little wear. The remaining sealing gap can be made very small. It suffices a gap width, which is equal to the thermal expansion (ie diameter increase) of the Zellenradseitenscheiben at the highest occurring operating temperature, plus the usual tolerances to compensate for discontinuities. The sealing effect achieved is very good because of the narrow sealing gap and the large gap length. At the same time eliminates all the disadvantages of the previous sealing arrangements, namely high wear, heating and thus stretching of the Zellenradseitenscheiben already due to the friction between these and the seal assembly, and high control effort to adjust the contact pressure of the seal assembly.

According to a development of the rotary valve, the sealing material is a stuffing box sealant material. The latter is a commercial product, especially in the form of profile cords of different cross-section, with well-known properties.

In the drawing, a rotary valve according to the invention is shown in simplified form in an exemplary embodiment selected. It shows:

Fig. 1, the rotary valve in longitudinal section, and

Fig. 2 shows the sealing arrangement reproducing region II in Fig. 1 on an enlarged scale.

The rotary feeder conventional design consists of a housing 1, the top side a Schüttguteinlauf 1a and the bottom has a bulk material outlet 1b. Between the inlet and the outlet side, a pressure difference in the order of eg consist of a few bars (hectopascals). The arranged in a cylindrical bore of the housing 1 cell wheel essentially comprises a shaft 2, a number (eg 12) Zellenradstege 3 and side windows 4a and 4b. The shaft 2 is mounted in lateral bearing caps 5a and 5b of the housing 1. Between each bearing cap 5a and 5b and the equilateral side window 4a and 4b, a seal arrangement is provided which avoids a leakage gas flow from the inlet to the outlet end (or vice versa) of the lock.

An essential feature of the seal arrangement according to Fig. 2 is the floating in relation to the housing 1 and the corresponding bearing cover arrangement of the filling ring, a deflection of the cellular wheel due to high pressure difference between the inlet and the outlet side of the lock and other, acting in the same way influences to follow without this additional, wear-promoting (coercive) forces arise.

In the in Fig. 2 illustrated seal assembly, the side plate 4b carries a welded-on metal ring 6c, which is attached to the outer periphery of the side plate 4b. Between the outer circumferential surface of the metal ring 6c and the cylindrical inner wall 1c of the housing 1 remains a sealing gap s. The bearing cap 5 b is circumferentially turned to a diameter larger than the diameter of the cylindrical inner space of the housing 1. In this way, an annular surface 1d lying in a radial plane is created, against which a filling ring 7c bears, which is shown here as consisting of two layers. It is essential that the filler ring 7c consists of an elastically or plastically deformable sealing material. Sealing materials which have been used for gland packing have proven particularly suitable. The filler ring 7c is in the axial direction by a

AT 404 352 Β

Metal profile ring 8e loaded, acting on the back of helical compression springs 8d, which are supported against the provided for this purpose with mounting holes bearing cap 5b. However, the metal profile ring 8e presses not only in the axial direction of the filler ring 7c but also encloses this over most of its outer surface. For this purpose, the metal profile ring 8e has on the inside a diameter step in which the filler ring 7c is received in a form-fitting manner. The filler ring 7c can therefore deform radially under the axial pressure of the metal profile ring 8e almost exclusively only in the direction of the metal ring 6c. Depending on the chosen sealing material, this deformation may be elastic or plastic. Due to the deformation disappears at this point, the gap s. Since the metal profile ring 8e and the filler ring 7c form a floating seal assembly, this is the inevitable, attributable to the described causes radial displacements of the metal ring 6c to follow, so that undesirably high frictional forces between the inner peripheral surface of the filler ring 7c and the outer surface of the metal ring 6c be avoided.