IE59928B1

IE59928B1 - A machine for the compression of a bulky mass

Info

Publication number: IE59928B1
Application number: IE81387A
Authority: IE
Original assignee: Tetra Pak Ab
Priority date: 1986-04-01
Filing date: 1987-03-30
Publication date: 1994-05-04
Also published as: IE870813L; ATE64567T1; SE8601459D0; DE3770850D1; EP0239858B1; SE8601459L; SU1630605A3; FI86045B; ES2022183B3; FI86045C; SE452723B; EP0239858A1; FI871281A; FI871281A0

Abstract

A machine for the compression of a bulky mass (2), e.g. plastic-coated, shredded waste paper, so as to form a compact, elongated, well-integrated body, e.g. a fuel body for heating purposes. The machine has a driven screw arrangement arranged centrally in a conically tapering space (10) which comprises on the one hand a rear feed screw (13), partly located in the said space, and on the hand a front compression screw (18), arranged concentrically in relation to the feed screw, both the said screws being rotatable at mutually unequal speeds.

Description

The present invention relates to a machine for the compression of a bulky mass, so as to form an elongated dense body, ahich machine comprises a space conically tapering towards an outlet opening and a driven screw arrangement arranged centrally in the space, wherein said screw arrangement comprises a rear feed screw with screw threads and a front compression screw with screw threads and wherein the screws are rotatable at mutually unequal speeds of rotation.

Every year several thousands oi tons of combustible industrial waste are produced whose only extractable economic value rests in tbe possibility oi utilizing as large a part as possible oi its latent energy content by aeans oi combustion, sor example, 3’or heating purposes. In order to sake such a recovery oi energy at all possible it is necessary aany times though to subject the waste to some type ei processing which means ia principle that, after sorting out the inferior material, the remaining, more combust ion-effective material is converted to © final form suitable for combustion, e.g. so-called fuel briquettes. This conversion of form or compression usually takes place with the help of a machine of the type which has been described above. One example of such a machine is disclosed in for example DE-A-3 429 848 to which is referred for further information.

The known machine described here functions well in association with waste of a more or less easily sliding character, rarely or never, on the other hand, with dry bulky refuse masses of the type of waste paper, especially plastic-coated waste paper oi the type which occurs in the manufacture of packing laminate for so-called non-returnable packages for fluid contents. The only possibility of converting such dry paper waste to effective formstable fuel briquettes with he help of the known machine oi the screw type has been, therefore, either to eke out the paper with waste material of the more easily sliding kind and/οι to add water Sn order to wet and thereby soften up the paper and transform it if into a more appropriate end easily processable consistency. Such necessary measures involved, however, a worsened heat economy, owing to the additional blending material as a rule being less combustion-effective than the pure" waste paper, whilst any transformation oi consistency with the help of . water usually required a subsequent energy-consuming heat treatment in order to dry the moist fuel body formed.

It is an object of the present invention, therefore, to provide & machine of the type as described above, but which in contrast to the known machine permits an effective compression oi combustible, bulky refuse, especially plastic-coated waste paper, without the previously necessary energy-impair ing pretreatment of the refuse material.

This object is achieved in accordance with the present invention in that the machine described ia the introduction has been given the characteristics specified in the elaims.

The Invention will be explained and described ia more detail in the following with reference to the attached drawing which schematically shows a very simple, but practical and wellfunctioning embodiment of the machine in accordance with the invention for the manufacture of form-stable fuel bodies from combustible, bulky refuse material, especially plastic-coated waste paper.

On the drawing Is thus shown a machine, which has been given the general reference designation 1, ia accordance with the present invention for the compression oi e bulky mass of combustible, dry refuse material 2 which in the example described here is assumed to ba plastic-coated waste paper. The machine 1 comprises mainly three machine sections, namely a feed-in section 3, an active working section 4 and a feed-out section 5, which are joined together to a machine unit which may be supported on a stand 5. The feed-in section 3 of the machine 1 comprises a box © open at the top which is limited by a horizontal bottom wall 7 ©nd substantially vertical side walls 8 to receive and collect waste paper 2 supplied from above which is to be compressed. The box 9 is connected through a hole provided in the front (lefthand) side wall 8 as the box with a conically tapering compression space 10 in a housing body 11 of tha active machine section 4 arranged against this side wall. In tha rear (righthand, side wall β of the box 9 a corresponding hole is provided for & hollow driving shaft 12 supported in the hole ia a rotatable manner for a feed screw 13 located in the lower part of the box, which has a rear screw section 13a located wholly in the box 9 with screw threads 14 of mutually equal pitch, and a front screw section 13b extending at least partly into the conically tapering space 10 comprising screw threads 16 with a pitch successively diminishing towards the space . Centrally inside the hollow of the driving shaft 12 is supported in freely rotatable manner a driving shaft 17 for a compression screw 18 arranged wholly inside the said space 10 in a straight line in front of the feed screw 13, with screw threads 19 whose pitch decreases successively towards the outlet opening 20 of the space 10. The driving shafts 12 and 17 can be driven in a Banner known in itself with the help of & suitable gear drive arrangement by means ox one and the same motor (not shown), and in accordance with the invention it is important here that the transmission ox power between the motor and the shafts 12 and 17 is adapted so that they can be driven at speeds of rotation freely adjustable in relation to each other. Preferably the shaft 17 for the compression screw 18 is adapted to be driven at twice the number ox revolutions as the shaft 12 for the Seed screw 13.

Vith the object of facilitating the feed-in of the bulky waste paper 2 into the compression space 10P this space has a ieed-in region 21 facing towards the box 9 with a somewhat larger taper then the front sone of the space 10, diminishing conically towards a more acute top angle. Furthermore the space 10 preferably has surface irregularities promoting the feed of the waste paper 2 in the form, for example, of parallel longitudinal grooves or ridges 23 spaced uniformly around the inner wail 22 oi the housing body 11 delimiting the space.

The ieed-out section 5 of the maehlne 1 finally comprises a hollow, mainly cylindrically shaped housing body 2« arranged against the housing body 11 and. located so that the axial, eylin5 drical cavity 25 ol the housing body 24 constitutes a direct continuation of the outlet opening 20 of the conical space 10.

The machine 1 in accordance with the present invention described above operates ia the following manner. With the help of the said motor (which may be a conventional electric motor of 55 kV with a motor speed ox 1470 rpm) the shafts 12 and 17 ©re driven via a suitable power transmission arrangement , because of the conical tapering of the feed-in zone 21,the bulky mass of paper waste thus fed will be subjected to a certain precorapression during the passage through the feed-in zone 21. This pr ©compression, which mainly implies a squeezing out of entrained air, is compensated slightly, though, in that the shaft as well as the pitch of the screw threads 21 of the front screw section 13b located partly within the feed-in zone 21 taper or decrease respectively in the direction of feed of the feed screw 13.

The paper waste thus advanced and precoxa pressed by the feed screw 13 through the feed-in sone 21 is advanced further through the space 10, with the help of the compression screw 18 arranged in front of the feed screw 13 and wholly in the conical space 10, into the cylindrical feed-out cavity 26 of the housing body 24 through the outlet opening 20.

Since the quantity of paper which is advanced through the feed-in zone 21 by the feed screw 13 is greater than the quantity which actually should be received by, and be advanced through,. the space 10, which successively tapers towards the outlet opening 20, this means consequently that a certain piling up oi paper waste ied must occur in the feed-in zone 21. However, in accordance with the invention this phenomenon is avoided by virtue of the compression screw 18 being rotated at a higher speed than the feed screw ig, ?aore particularly at such a speed that the quantity which is advanced per unit oi time by the feed screw 13 exactly matches the quantity per unit of time which the compression screw 1© at the higher speed ίε capable oi advancing into the free space between the threads 1© and the inner surface of the housing body 11. This free space decreases, however, successively towards the outlet opening 20 and during the advance with the help oi the compression screw 18 heat will be generated owing to inner friction ia the paper waste thus advanced. The frictional heat generated is sufficiently strong for the plastic coating (e.g. polyethylene) on the paper bits to Belt and thereby effect a fusing together οί adjoining paper bits, so as to form an elongated, compressed and, with the help of the paper bits so fused together, form-stable fuel body which is ied out continuously through the SO cavity 26 ia the housing body 24.

Claims

1. A machine for the compression of a bulky mass so as to form an elongated dense body/ which machine comprises a space conically tapering towards an outlet opening and a driven screw arrangement arranged centrally in the space , wherein said screw arrangement comprises a rear feed screw with screw threads -and a front compression screw-/with screw threads and wherein the screws are rotatable et mutually unequal speeds of rotation, characterised in that the screw threads of the rear feed screw as -jell as the screw threads of the front compression screw have pitches decreasing towards the outlet opening and In that ©aid space has a rear feed-in region with a somewhat larger taper than the front' sone of th® space.

2. A machine In accordance with claim 1, characterised In that the feed screw has on the one hand a rear cylindrical screw section located outside the conically tapering space and on the other hand a conically tapering screw front section located wholly within this space.

3. » A machine In accordance with claim 1 or 2, characterized in that the front end of the conically tapering space is connected directly to a cylindrical outlet duct.

4. ,. A machine for the compression of a bulky mass as claimed, in claim 1, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.