GB2074528A - Conveyor for a can sterilizer - Google Patents

Abstract

A conveyor for a can sterilizer comprises a conveying chain (1), arms (3) connected to the chain and buckets (4) fixed stiffly to each arm. Each arm is connected to two adjacent pins (2) of the conveying chain. This connection is preferably a detachable one. Each bucket can be made of an outer part (6) and an inner part (7) pivotally connected thereto. <IMAGE>

Description

SPECIFICATION Conveyor for can sterilizer This invention relates to conveyor for a can sterilizer, the conveyor having a conveying chain, an arm connected to the chain and buckets fixed stiffly to the arm.

In the course of can manufacture, a heat treatment is applied to the cans. This heat treatment is called sterilization. The cans are conveyed through a can sterilizer, for example through a divided hydrostatic sterilizer, by means of the conveyor.

An excess pressure develops inside the can, as a result of the heat treatment. This internal excess pressure should be compensated by an increased external pressure in the sterilizer to avoid the cans bursting or exploding. This problem is solved in a divided hydrostatic sterilizer by leading the cans through a plurality of adjacent stages with continuously increasing pressure into the inside of the sterilizer and then through a plurality of stages with decreasing pressure from the inside to the outside thereof. The conveyor describes a serpentine path with two 1 800 turns in every stage. The cans are arranged for this treatment in buckets attached to the conveying chain of the conveyor.

Nowadays, there is an ever increasing demand for cans, and the development of the technology of the canned food industry is directed therefore to increasing the productivity of sterilization. The speed of the sterilization cannot exceed a certain limit, and the time of heat treatment cannot be reduced without the danger of the canned food spoiling. Therefore, the number of cans treated at a time has to be increased. However, such an increase is limited by the outer dimensions of the sterilizer. Furthermore, the conveyor should be designed for easy introduction and removal of the cans and for a proper contact between the treating agent and the cans.

Buckets for a can sterilizer are disclosed in Hungarian Patent Specification No. 170.128.

Those buckets are attached to a drag chain by means of arms assembled on the buckets. A bearing is provided between the arms and the chain pivot, and a guiding path having straight and/or curved sections is used to guide the buckets, which are connected to each other. Thus, the buckets are guided there along a forced trajectory. Accordingly, guiding path elements are built into the sterilizer, and the arms must be joined to the chain with special pivot bearings, where a special grease lubrication is needed. The guiding elements must be arranged with great accuracy to avoid the buckets getting stuck in the curves of the conveyor. If damage or breakdown of the buckets occurs, they can be mended or changed only with great difficulty, and the sterilizer is idle for a long time.Even the endeavour to reduce the space occupied cannot be satisfied, since the guiding elements need a large space and the chain has a large turning radius.

An object of the present invention and embodiments thereof is to provide a conveyor by means of which a greater number of cans can be treated at a time, which is reliable, which can be built into existing sterilizers without the need of substantial rebuilding, and which reduces the working costs and the space occupied.

A basic idea of the invention is to reduce the space occupied by narrowing the turning radius of the conveyor chain and by eliminating the guiding elements. This is achieved by connecting the arms holding the buckets to the conveyor chain in a particular manner. Thus, the buckets will be guided by means of this connection between the chain and the arm. In other words, the arm should be fixed to the chain for holding their relative position in the course of the whole movement through the sterilizer.

Accordingly, the invention provides a conveyor for a can sterilizer, comprising a conveying chain, an arm connected to the chain and buckets fixed stiffly to the arm, wherein the arms are connected to two adjacent pins of said chain.

Thus, the buckets will be turned at the 1 80cm turnings of tha conveying chain without any guiding or other element, just by the fact that the arm is fixed to two adjacent pins. The arm will therefore have the same relative position to the chain link as the two pins have. Therefore, there is no relative motion between the arm and the pins, and therefore, not need to employ joint or bearing.

This simplifies the construction, and, what is more, the strength of the connection between the bucket and the chain is increased. It is highly preferable if this connection is a detachable one. The buckets can then very easily be changed or removed.

For introducing and removing the cans from the buckets the buckets are each preferably of two parts, namely an inner part and an outer part. The outer bucket part is fixed to the arm and the inner bucket part is rotatably mounted in the outer one.

The inner bucket part is more inclined to get damaged, and therefore it is highly preferable for the inner bucket part to be interchangeably mounted in the outer part.

In the course of the conveying process, the buckets should remain closed, and it is therefore desirable to provide a retaining portion on one side of the inner bucket part.

To increase the number of cans which can be treated at a time in the sterilizer, at least two buckets can be fixed stiffly to the arm.

In the accompanying attached drawings: Fig. 1 is a schematic plan view of a preferred embodiment of the invention; Fig. 2 is a schematic plan view of another preferred embodiment of the invention; Fig. 3 is a side elevational view of the embodiment of Fig. 1; Fig. 4 is a view, partly in section, according to arrow IV in Fig. 3; Fig. 5 is a side elevational view of the embodiment of Fig. 2; Fig. 6 is a view, partly in section, according to arrow VI in Fig. 5; Fig. 7 is a side elevational view of a preferred type of bucket for use in this invention; Fig. 8 is a view as in Fig. 7, but with a reverse direction of motion; Figs. 9a to 9c show the embodiment of Fig. 2 with one bucket, two and four buckets, respectively; Fig. 10 is a schematic side elevational view of the embodiment of Fig. 2 in an operational position: in the curve of the conveyor; Fig. 11 is similar to Fig. 10 but with two buckets; Figs. 1 2a and 1 2d are perspective views of several examples of buckets; and Fig. 13 is a working plan view of the embodiment of Fig. 2.

Fig. 1 shows an exemplary embodiment of the invention, in which a bucket 4 is connected to a conveying chain 1 of a conveyor, with the bucket 4 being stiffly fixed to an arm 3 and arm 3 being connected to two adjacent pins 2 of the conveying chain 1. The stiff fixing is achieved, for example, by welding. Two adjacent pins in a chain always belong to one chain link. Therefore, bucket 4 connected to these pins 2 moves with a chain link and will always have the same position relative to this chain link. The chain links are guided by driving or guiding sprocket wheels of the sterilizer, in the curved portions of the conveyor path. Thus, the bucket 4 attached to a chain link will turn in the curves without any guiding element.

In course of the conveying, there is no relative motion between the pins 2 and the arm 3. Thus, there is no need for a demanding joint or bearing, and the parts can even be connected with a clearance fit. This feature is illustrated in detail in Fig. 13 which is described below.

Another embodiment is shown in Fig. 2 in side elevational view. In Fig. 2. the conveying chain 1 is the closest to us and the buckets 4 are rising out from the plane of the drawing backwards, to the rear.

The connection to two pins 2 can be achieved as shown in Fig. 1, wherein one of the connections is off-centre and the other central. The term "off centre connection" is to be understood as meaning that the connecting pin lies outside the orthogonal projection of the bucket 4 on the chain 1. The term "central connection" is to be understood as meaning that the pin 2 is inside that orthogonal projection.

Another possible type of connection is shown in Fig. 2, wherein both connecting pins 2 are off centre. Also in this case the conveyor operates as described previously, and each bucket 4 will have always the same position relative to the chain link as the connecting pins 2 which belong to that link.

A side elevational view is shown in Fig. 5, and a view according to arrow VI of Fig. 5 is shown in Fig. 6.

Both of the above described types of connection have the advantage of not requiring a demanding joint at the connections. This feature is important as regards changing buckets 4 which can easily get damaged. Furthermore, there is no difference between the embodiments as to the number of cans which can be treated at a time, because in each case the same numbers of arms can be attached to the conveying chain 1. The arm 3 in Fig. 3 can be manufactured more simply.

Productivity can be further increased by increasing the number of arms 3 mounted on the chain 1 by raising the number of buckets 4 mounted on the arm 3. This is illustrated in Figs. 7 and 8, wherein two buckets 4 are stiffly fixed to one arm 3, i.e. a twin bucket arrangement. The introduction of the cans is achieved by the buckets 4 having two parts. An outer bucket part 6 is stiffly mounted on arm 3 by, for example, welding. An inner bucket part 7 is pivotally connected to the outer bucket part 6.

In Fig. 7, the bucket 4 on the right side is in ari opened position, in which the cans can be introduced or removed. The direction of closing is indicated by arrow Z. A closed bucket 4 is shown at the left side of the Figure. The direction of opening the inner bucket part 7 is indicated by arrow NY. The inner bucket part 7 has a retaining portion which can be provided by turning all or part of the edge of the inner bucket part 7 upwards. This retaining part has the function of preventing the undesired opening of inner bucket part 7 in the course of travelling through the sterilizer. The retaining part also keeps the inner bucket part 7 from turning too far behind the cans introduced in to the bucket 4.

The direction of motion of the conveying chain 1 is shown by an arrow H which is opposite to the direction Z of closing. This ensures that the bucket 4 will not be opened in the course of sterilization.

If the direction of motion H changes, as in Fig. 8, the relative position of the outer bucket part 6 and the inner bucket part 7 must be changed too.

Thus, the direction NY of opening will always be identical with the direction of motion H, the direction of closing Z always opposite to it.

In this embodiment, the inner bucket part 7 is more exposed to damage, and must often be repaired or replaced. Such repair need not involve changing of the entire bucket 4, and in most cases it is sufficient to mend only the inner bucket part, 7.

A single arm 3 can carry several buckets 4. This is shown in Fig. 9c, which is an example involving four buckets 4. The buckets 4 are preferably arranged so that they are symmetrical to a plane lying perpendicular to the arm 3 through points of suspension (connecting chain pins 2). This results in no additional stiain or loading in the arm 3 or the pins 2 or the conveying chain 1.

Fig. 10 and 11 show the critical position of conveyor for two embodiments in a curve of the sterilizer. The bucket units turn there without any aids or supplementary means such as guiding elements or guide path members and without the danger of the buckets 4 touching one another or the surrounding walls of the sterilizer. The turning cycle is a very narrow one because of the small turning radius.

Buckets 4 which fulfill the requirement of good contact between the treated cans and the treating agent are illustrated in perspective in Figs. 1 2a, 1 2b, 1 2c and 1 Zd, wherein all buckets 4 have a perforated mantle. In Fig. 1 2a, a longitudinal slit is provided in the mantle to facilitate the introduction and removal of cans. For the same purpose, bucket 4 in Fig. 1 2b is assembled from two parts. In Fig. 1 2c the bucket 4 is built from flat plates. The slit on the mantle must not be provided over the whole length of the bucket 4 but only over a part of it. This is shown in Fig. 12d.

In Fig. 13, a working plan is provided to illustrate the real conditions of a particular embodiment. Fig. 13 shows the connections between the arm 3 and the pins 2 of the chain 1 as well as between the bucket 4 and the arm 3.

The embodiment corresponds to that shown schematically in Fig. 2. Between pin 2 and arm 3, a clearance fit is provided, arm 3 being held in place by means of a cotter pin. To remove the bucket 4, all that is necessary is to remove the cotter pins from the pins 2. Fig. 1 3 also shows how easily the inner bucket part 7 can be removed: only a bolt 5 need be taken out.

The operation of the conveyor according to the invention is very simple. The cans are introduced into the buckets 4 at the entry of the sterilizer, after which the buckets 4 are closed by turning the inner bucket parts 7 in the direction Z or, in the case of other embodiments, with the help of additional closing devices or of curved arms of the adjacent buckets 4. This happens after the conveying chain 1 is set in motion on the very first part of the path. The treatment of cans will be completed as they travel through the sterilizer, through the respective stages. At the exit of the sterilizer, the buckets 4 are opened by turning the inner bucket parts 7 in the direction NY or removing the closing devices, and the cans are removed from the buckets 4.

This simple operation can be automated very easily, so that a sterilizer can be provided in which the cans need not be touched by human hand, and in whose operation a considerable sum of money can be saved.

Claims (10)

1. A conveyor for a can sterilizer, comprising a conveying chain, an arm connected to the chain and buckets fixed stiffly to the arm, wherein the arms are connected to two adjacent pins of said chain.

2. A conveyor as claimed in claim 1, wherein the arm and the chain pins are detachably connected to one another.

3. A conveyor as claimed in claim 1 or 2, wherein each bucket is assembled from two parts, namely an outer bucket part fixed to the arm and an inner bucket part rotatably mounted in the outer bucket part.

4. A conveyor as claimed in claim 3, wherein the inner bucker part is removably mounted in the outer bucket part.

5. A conveyor as claimed in claim 3 or 4, wherein a retaining portion is provided on one side of the inner bucket part.

6. A conveyor as claimed in any one of the preceding claims, wherein at least two buckets are stiffly fixed to the said arm.

7. A conveyor as claimed in any preceding claim, wherein the buckets have a perforated mantle with a circular cross section.

8. A conveyor as claimed in claim 7, wherein the bucket is open on both its ends and has a slit on the mantle parallel to the longitudinal axis of the bucket as well as curved arms on the adjacent bucket and/or special closing devices for closing both ends of the bucket.

9. A conveyor as claimed in claim 8, wherein each bucket is assembled entirely or partly from straight plates.

10. A conveyor for a can sterilizer, substantially as herein described with reference to any one of the embodiments shown in the accompanying drawings.