GB2031753A - Waste pulpers - Google Patents

Abstract

A pulper for pulping waste material of the type comprising a body (34) and an abrading disc (37) therein driven by an electric motor (39) to effect abrasion of waste material in contact with the disc (37), is characterised by supplementary abrading means (31, 32) in spaced opposed disposition relative to the disc (37) and positioned to contact and abrade buoyant waste material supported on the vortex created by the rotating disc (37). The supplementary abrading means (31, 32) may be a second abrading disc (31) rotatably driven by the motor (39) or a separate motor (33) and mounted in an inclined sidewall (35) of the body (34). Alternatively or additionally the supplementary abrading means may be a fixed, preferably frusto-conical surface of the body (34). <IMAGE>

Description

SPECIFICATION Waste pulpers This invention relates to pulpers used for pulping waste materials and paper, and has particular, though not exclusive, reference to pulpers for pulping such as catering waste in self-service restaurants and aircraft.

Pulping machines are known the basic principle of operation of which involves the formation of a vortex in the liquid medium by the rotating action of the pulping disc, the surface of such disc being composed of hard steel teeth.

Centrifugal forces acting on the liquid medium cause turbulence therein and create a reverse underflow which draws suspended materials down onto the rotating disc, the suspended materials being broken up and eroded into smaller particles at such disc.

Eventually these particles of waste material are sufficiently small to pass through holes in a sizing ring and are then pumped away.

Unfortunately very lightweight materials, such as plastic drinking cups and polythene bags, which tend to be buoyant because they contain air, do not get drawn down onto the pulping disc but tend to accumulate at the top of the vortex, the machine having to be stopped while such materials are removed.

The accumulation of such lightweight materials seems to be a common problem with all pulpers of this type, which pulpers tend to be relatively small and hence involve frequent downtime for cleaning. Furthermore more and more such lightweight materials are in use and in consequence the problem is becoming increasingly more serious.

The primary object of the present invention is to provide a pulper of such construction as will minimise, or at best eliminate, the shortcomings of conventional pulpers are regards the treatment of lightweight, and buoyant materials.

According to the present invention, a pulper for pulping waste materials and paper and comprising a body part to receive the waste material, an outlet in such body part, and an abrading disc adjacent such outlet adapted, upon rotation, to effect abrasion of waste material, in contact therewith, the outlet being adapted to allow passage therethrough of particles up to a predetermined maximum size, is characterised by a supplementary abrading means in spaced opposed disposition relative to the abrading disc and positioned to receive into abrasion contact therewith materials supported by the vortex arising from rotation of the abrading disc.

According to a preferred feature, the supplementary abrading means includes a further rotatable abrading disc.

The invention will now be described further, by way of examples only, with reference to the accompanying diagrammaic drawings in which: Figure 1 is a vertical section through a first embodiment of the invention wherein the supplementary abrading means comprises a fixed element of elements; Figure 2 is a vertical section through a second embodiment wherein the supplementary abrading means comprises a rotatable abrading disc.

Referring now to the drawings, and particularly to Fig. 1 thereof, a pulper comprises a generally cylindrical body part 11 having a reduced diameter lower region 1 2 of small axial extent, an electric motor 1 3 having its output spindle 14 arranged coaxially with and extending into the body part 11 secured to the underside of such body part, and an abrading disc 1 5 secured to the spindle for rotation therewith.

The disc 1 5 is located within the reduced diameter lower region 1 2 of the body part, and a sizing ring 1 6 of cylindrical form is provided adjacent the periphery of the disc to extend upwardly from the plane of such surface, the upper end of the ring 1 6 having a radially outwardly directed flange 1 7 for seating on an annular lip 18 at the junction between the lesser and greater diameter portions of the body part to support the ring in coaxial relationship with the abrading disc.

Material pulped by the disc to dimensions less than a predetermined maximum dimension will pass through apertures 1 9 in the sizing ring 1 6 under the centrifugal action of the abrading disc on rotation thereof, and will be discharged from the pulper through outlet means, not shown, in the bottom of the body part.

As thus far described the apparatus is of conventional form.

In accordance with the present invention, a further abrading means is provided in spaced disposition to rotatable abrading disc 15, the said further means comprises an inclined part conical surface 20 arranged in coaxial disposition with disc 15, surface 20 including a multiplicity of hardened teeth 21 arranged in opposed disposition relative to such disc. The teeth 21 are so positioned in relation to the rotatable disc 1 5 as to be in the path of the vortex caused by such disc, and accordingly any buoyant materials supported by the vortex will be subjected to the abrading action of the teeth 21 provided on surface 20 on movement relative to such teeth.

In an alternative embodiment, see now Fig.

2, the supplementary abrading means comprises an abrading disc 31 secured to the spindle 32 of an electric motor 33 mounted on the body part 34, the disc 31 being located inwardly of a downwardly facing inclined wall 35 to the body part and there being an annulus 36 coaxial with and adjacent the periphery of such disc. In use, waste material supported by the vortex created by primary abrading disc 37 on the rotation thereof is subjected to the abrading action of cutting teeth 38 on supplementary disc 31, the rotational action of disc 31 causing further turbulence in the liquid in the pulper and possibly displacing buoyant material from this position in the upper region of the vortex.

The invention is not restricted to the exact features of the embodiments herein-described and illustrated, since alternatives will readily present themselves to one skilled in the art.

Thus, for example, it may be found convenient to provide both rotatable and non-rotatable supplementary abrading means in a single pulper.

Claims (10)

1. A pulper for pulping waste materials comprising a body part adapted to receive the waste material, an outlet in the body part and an abrading disc adjacent the outlet adapted, upon rotation, to effect abrasion of waste material in contact therewith, the outlet being adapted to allow passage therethrough of particles of up to a predetermined maximum size, characterised by a supplementary abrading means in spaced opposed disposition relative to the abrading disc and positioned to receive into abrasion contact therewith waste material supported by the vortex arising from rotation of the abrading disc.

2. A pulper according to claim 1 wherein said supplementary abrading means comprises an annular surface of said body part.

3. A pulper according to claim 2 wherein said annular surface is frusto-conical and is coaxial with said abrading disc.

4. A pulper according to claim 1 wherein said supplementary abrading means includes a second abrading disc.

5. A pulper according to claim 4 wherein said supplementary means is mounted for rotation relative to said body part.

6. A pulper according to claim 5 wherein separate drive means is provided for said abrading disc and said second abrading disc.

7. A pulper according to claim 4 or claim 5 wherein the axis of said second abrading disc is coplanar with but inclined relative to the axis of said abrading disc.

8. A pulper according to claim 7 wherein said second abrading disc is mounted on an inclined sidewall of said body part.

9. A pulper according to any one of the preceding claims wherein said supplementary abrading means comprises a rotatably mounted part and a non-rotatable part.

10. A pulper for pulping waste materials substantially as hereinbefore described with reference to and as illustrated in Fig. 1 or Fig.

2 of the accompanying drawings.