FI72376C - FOER PUMPNING AV I SYNNERHET CELLULOSA OCH ANDRA FIBERSUSPENSIONER OCH DYLIKT AVSEDD PUMP. - Google Patents

Description

© ® rnl,., ADVERTISEMENT

B 11 UTLÄG G NIN G SSKRI FT 72 3 76 (51) Kv.lk.4 / lnt.CI.4 F 04 D 7/04, 29/18 FINLAND - FINLAND (21) Patent application - Patentansökning 456/73 (22) Application date - Ansökningsdag 15.02.73 (Fl) '' (23) Starting date - Giltighetsdag 15.02.73 (41) Has become public - Blivit offentlig 22.08 73

National Board of Patents and Registration Date of publication and publication. -

Patent and registration authorities' 1 Ansökan utlagd och utl.skriften publicerad 3O.OI.87 (86) Kv. application - Int. ansökan (32) (33) (31) Privilege claimed — Begärd priority 21.02.72 Sweden-Sverige (SE) 2059/72 (71) Jönköpings Mekan father Werkstads AB, Kyrkogatan 9, Jönköping,

Sweden-Sweden (SE) (72) Bengt Gustav Blomsten, Jönköping, Rolf Gunnar Holm, Jönköping,

The invention relates to a pump according to the preamble of claim 1. The invention relates to a pump according to the preamble of claim 1, in particular to a pump for pumping cellulose and other fibrous suspensions and the like, for pumping cellulose and other fibrous suspensions and similar fibers. , In the design of the impellers of such a pump, the aim has usually been to achieve the most calm, vortex-free inflow of pumped liquid possible. To achieve this, the angle of incidence of the pump wheel blades has been chosen so large that the inflowing pumped liquid has a final velocity relative to the pump impeller blades which is substantially parallel to the surface of the inlet edge of these blades. This is illustrated in Fig. 1, which shows a section at the inlet edge of the vane, which section is formed by a section made between the rotating surface formed by the flow line as the pump rotates and the impeller vane.

In Fig. 1, the wing 1, the axis of rotation 2 of the pump impeller, the inlet angle of the pumped liquid by means of flow lines 3 with arrows are indicated by reference numerals in Fig. 1. It is observed that these follow calmly and vortices without generating the surfaces of the wing 1. Figure 1 also shows cellulose or other fibers dispersed or slurried in and part of the pumping agent 2 72376. These fibers 4 have caused difficulties in remaining to hang on the inlet edge, as shown in Figure 1. The tendency of the fibers or yarns to adhere to such adhesion is relatively high, because the inlet edge is thin and the flow is substantially parallel to the wing surface.

Another difficulty that such wires or fibers among the pumped liquid cause in the rear impellers of the pump impellers is that the fibers penetrate and become entangled between the rear vanes and the cover plate of the pump housing.

These problems are addressed in Allan Wirzenius's book "Centrifugal Pumps" on page 282. According to this literature reference, the wing tip (impeller inlet edge) is provided with a large radius of curvature and made continuously tapered as is customary in waste pumps to facilitate mechanical impeller balancing, among other things.

The main object of the invention is to eliminate the above-mentioned and other similar difficulties when pumping substances containing yarns, fibers and the like. This object is achieved by providing the pump in accordance with the invention with special features which will become apparent from the characterizing part of claim 1.

Since the inlet edge of the impeller vane according to the invention is tubularly thickened and trough-shaped discontinuously in the direction of rotation of the impeller from its front side, advantageous vortex formation or turbulence is provided

Other features and advantages of the pump according to the invention will become apparent from the following detailed description and the accompanying drawings, in which Figures 2 to 4 schematically illustrate an exemplary embodiment of the invention, but by no means limited to this example.

3 72376

Figure 1 shows, as shown above, a section taken from the impeller blade at the point closest to the inlet edge.

Figure 2 shows a top view of a pump impeller shaped in accordance with the invention.

Fig. 3 shows an axial section made along the vane between the halves of the impeller of Fig. 2 and other parts of the pump cooperating with the impeller.

Fig. 4 shows a section analogous to Fig. 1 along the line IV-IV shown in Fig. 2 through a point of the impeller blade formed in accordance with the invention closest to the inlet edge.

The impeller of the pump, denoted as a whole by the number 5 in Figures 2 and 3, to which reference is now made, is located in the housing 6 of the pump, which is shown only in the drawings only in Part. The essential parts of the impeller 5 are a substantially plate-like body 7 and the vanes 1 attached thereto. As can be seen more clearly from Figure 2, the vanes 1, which in the exemplary case are four, are substantially perpendicular to the flat rear side of the plate 7 over their entire height and backward curved. Figure 2 shows. The wings 1 are connected to the plate 7 along their inner and rear edges. According to the invention, the inlet edge 10 of the vanes is substantially perpendicular to the axis of the impeller, and further has an inlet angle of about 50 ° to 80 ° to 90 ° to 100 °. By making the entry angle so large, the desired turbulence and vortex formation in this case is provided at the entry point of the wing, which is indicated by reference numeral 11 in Fig. 4 and which tears off any pulp fibers and the like which may be stuck to the entry edge. This turbulence has not seemed to bring with it any hydraulic disadvantages in pumping the pulp, at least at concentrations of 3 to 8%.

4 72376

Furthermore, according to the invention, the inlet edge 10 of the wings 1 is tubular in shape in front of the wings with respect to the direction of rotation of the impeller 5 and is not, as usual, thinned from the inlet edge. This structure causes the pulp fibers 4 to tend to wrap considerably less around the inlet edge. In addition, the inlet is then less sensitive to different flow angles. In other words, a "wider" efficiency curve of the pump is obtained, as a result of which the pump can be used in a wider operating range while the efficiency remains acceptable. In addition, a more even and stable operation of the pump is obtained. With high abrasives, the service life of the pump impeller is increased because the inlet edge is thickened.

According to the invention, in addition to the inlet edge 10 of the vanes 1, it is located in a substantially (circular) cylindrical part of the inlet of the pump. In the embodiment of the invention shown, in which the inlet edge 10 is perpendicular to the axis of rotation 2, this causes the flow of substance to take place perpendicular to the inlet edge 10. This in turn reduces the risk of the pulp fibers wedging in the gap 12 (Figure 3) between the impeller blades 1 and the adjacent wheel cone. This in turn causes less wear on the vanes 1 and the wheel cone 13.

The constructional cases described above and shown in the drawings are, of course, to be considered only as examples, to which the invention is not only limited, but can be modified in detail in many ways within the scope of the following claim.