WO1988004145A1

WO1988004145A1 - Method, equipment and transport container to be used in a loading system for plastic bags

Info

Publication number: WO1988004145A1
Application number: PCT/US1987/003201
Authority: WO
Inventors: Johannes Hoppe; Daniel Lambertus Moellenkamp
Original assignee: Baxter Travenol Laboratories, Inc.
Priority date: 1986-12-11
Filing date: 1987-12-02
Publication date: 1988-06-16
Also published as: NL8603158A

Abstract

A method and apparatus for continuously sterilizing by heat treatment of liquids packed in plastic bags includes a treatment chamber, an endless conveyor inside the chamber, a loading station (10) and an unloading section (28). The conveyor includes through shaped carriers which receive, transport and then discharge bags being sterilized. The loading station (10) has at least one endless chain (29) constructed from a roll of transparent containers. The containers are pivotally connected to each other, with each container receiving one plastic bag. The chain (29) is provided with a drive (31) for moving in steps. The chain (29) moves in a direction transverse to the movement of the conveyor in the loading station (10). The transport containers unload the bags onto the conveyor.

Description

Method, equipment and transport container to be used in a loading system for plastic bags

The invention relates to a method for the loading of a continuous sterilizer for liquids packed in plastic bags (pouches), the sterilizer being composed of a treatment chamber through which an endless conveyor moves which, outside said chamber, traverses a cooling section, an unloading station, a loading station and a heating section, which conveyor is equipped with trough- shaped carriers, arranged transversely thereto, provided with compartments, situated in line with each other, which are each suitable for receiving, transporting and again discharging a bag to be sterilized.

A method of this type has already been used fOr the loading of bottles filled with a pharmaceutical liquid as described in the journal PHARMA-International, No. 1, 1968 by Ing. K. RUIG. A good four years later the same author described further.additional details for the application to the sterilization of infusion liquids in plastic bags in the same journal PHARMA International No. 5, 1972. In these publications no details were given in relation to the Loading system to be used in this connection. Continuous sterilizers for the thermal treatment of goods packed in containers (generally small cans or glass pots or bottles) such as preserves or milk products are known per se in various constructions. For the use of a steam atmosphere under increased pressure resulting from the use of a gas supply to the treatment chamber of a continuous sterilizer reference can be made to the British patent 974.659. In this known device spraying elements are also used in the cooling system to increase the caloric heat exchange. Another example of a heat treatment with steam using overpressure resulting from the supply of additional gas is the US patent 1,584,397. Finally, reference is further made to the US patent 3,619,126 from which a continuous sterilizer is known which has a treatment chamber inside which an overpressure is brought about by supplying additional gas while, in addition, spraying elements are present for increasing the heat transfer.

The execution of the method described in the introduction may give rise to problems in the processing of plastic bags which do not readily lend themselves to the application of the same manner of load ing into the trough- shaped carriers such as are used in the case of small cans or glass bottles. The sliding resistance of plastic bags is considerably larger than the slipping resistance of the known metal or glass containers. The object of the invention is therefore to provide a method in which the loading of plastic bags into the compartmentalized carriers is possible at an acceptable rate. This object is achieved according to the invention in that the bags to be sterilized are first placed one by one in a row of transport containers which are each formed with a displaceable base, that subsequently said transport containers are brought from a loading zone to an unloading zone situated In the loading station above a horizontal path section of the endless conveyor with Its carriers and- that the base of each transport container is then swung aside at an instant in time at which a moving carrier is located under the containers.

Theoretically, the method can be carried out using a single row of transport containers which must then, however, be filled fairly rapidly and subsequently moved from the loading zone to the unloading zone in order, additionally, to be emptied and subsequently to be returned, to the loading position, all of this within the so-called cycle time of the continuous sterilizer. This cycle time is equal to the distance between two adjacent carriers in the conveyor divided by the rate of advance of the conveyor. This may result in an excessive loading of the operating individual who places the plastic bags in the transport container.

An improvement of the method and a reduction of the work loading of the operating individual can be achieved according to the invention if at the loading zone the bags are placed in a number of rows of transport containers, situated in parallel next to each other, which are simultaneously moved from the loading zone to the unloading zone. By coordinating the movement of the containers in the correct manner with the advance of the conveyor, the available cycle time can be multiplied by a factor which is equal to the number of rows of transport containers.

The invention is also embodied in a continuous sterilizer for the thermal treatment of liquids packed in plastic bags comprising a treatment chamber provided with heating means, further comprising an endless conveyor for the bags, which conveyor traverses a loop- shaped path inside said chamber and, outside thereof, a cooling section, an unloading station, a loading station and a heating section, the conveyor being equipped with trough-shaped carriers, arranged transversely thereto, provided with compartments, situated in line with each other, which are each suitable for receiving, transporting and again discharging a bag to be sterilized. The loading system according to the invention is realised in a sterilizer of this type in that the loading station is provided with at least one endless chain constructed from a row of transport c o n t a i n e r s , c o n n e c t e d p i vo t a b l y t o e a c h o t h e r , w h i c h can each receive a plastic bag, which chain is provided with a drive for a stepwise displacement e transversely to the direction of advance of the conveyor in the loading station, and that means are present for the unloading of the transport containers above a carrier. A number of transport containers corresponding with the number of compartments in a carrier is filled with a bag and in the period when the chain is stationary, which is necessary for unloading the containers, a subsequent number of containers can be filled.

In another aspect, the invention relates to a transport container to be used in the method specified above and sterilizer. According to the invention, said transport container is distinguished by an oblong, in cross section U-shaped, construction with two upright side walls, a base which can be swung downwards and a length corresponding to a single compartment in the carriers of the continuous sterilizer. Said containers can be pivotably linked to each other to form an endless chain which can then be driven intermittently in one direction.

The features specified above as well as further characteristics of the method, the sterilizer and the transport container according to the invention will be explained in more detail by reference to the drawing which shows a diagram of the continuous sterilizer and some views of the loading station to be used in it and of the transport container.

Fig. 1 is a diagrammatic side view of an embodiment of the continuous sterilizer.

Fig. 2 is a plan view on an enlarged scale of the Loading station on the left-hand side of the continuous sterilizer in Fig. 1.

Fig. 3 is a front view, enlarged further, along the arrows III-III in Fig. 2.

Fig. 4 is a perspective view of a transport container, a section of which is cut away. Figs. 5 and 6 are respectively a rear view and a bottom view of the transport container.

The construction of the continuous, sterilizer according to the invention has already been described to a considerable extent in the journal PHARMA-International No. 1, 1968 mentioned above and consists of four vertical towers A-0 which are each subdivided into a number of columns. The columns 1 and 2 form the first tower A, the tower B consists of the columns 3 and 4 while the towers C and 0 are constructed from the columns 5 and 6, and 7 and 8 respectively. The tower A forms the heating section, the tower S the treatment chamber, the tower C is a transition zone and the tower D forms the cooling section.

In addition, the device is provided with an endless conveyor 9 which traverses a loop-shaped path within the heating section A, the treatment chamber B, the transition chamber C and the cooling section D. In addition,, the conveyor passes a loading station 10 and an unloading station 11. The conveyor 9, which is guided along a number of wheels 12, is closed at the bottom of the device by means of the inactive linking part 13 of the path. During operation a pressure-controlling liquid seal or hydrostatic limb is produced in the usual manner in the columns 2 and 7. The conveyor 9 is provided over its entire length with trough-shaped carriers having compartments in line with each other which are each suitable for receiving, transporting and discharging again a bag to be sterilized. These carriers 14 are shown diagrammatically in Figs. 2 and 3 and are described in more detail in patent application no..(.855121). The loading of the equipment in Fig. 1 takes place by means of at least a row of transport containers 15. As can be seen in Fig. 4, said container has an oblong, and in cross section U-shaped, construction with two upright side walls 16, 17 and a base 18 which can be swung downwards. Each container 15 is provided manually with the plastic bag to be treated in the sterilizer. The number of containers 15 in operation at the same time corresponds to the number of compartments in each carrier 14. Each container 15 is provided with two end walls 19. The side wall 16 is folded into a J shape in cross section. The second side wall 17 has an S-shaped profile in cross section. The base 18, which is also folded, is formed with a longitudinal edge 20 bent over at right angles which is provided with fixing elements

21, formed with increased thickness, for a pivot shaft

22. Said shaft is mounted in a support element 23 accommodated in a recessed section of the S profile.

Each transport container is further provided at both ends with a projection 24 for the pivoted coupling of containers to each other. There is, furthermore, a magnetic lock 25 which can hold or release the base 18 to unload a received bag 26.

The loading station 10 can be most clearly seen in Figs. 2 and 3. Three endless chains 29 of containers 15, which are coupled to each other, are disposed transversely to the horizontal path section 27 of the conveyor 9. Depending on the number of compartments in each carrier 14 (e.g. three or five) there may be an equal number of containers 15 above the path section 27, the lock 24 being operated at the correct instant in time and the base 18 of said containers being swung open. The bags 26 present at this unloading zone 28 then fall into the respective and continuously moving carrier 14. In the loading station 10 shown, three chains 29 are present which are intermittently and commonly driven by means of a reversing wheel 30 and a drive motor 31. The other wheels 32 are at a distance from the path section 27 so that a loading zone 33 is produced. Here the operating personnel can fill each of the transport containers 15 with a plastic bag 26. After a stepwise displacement of the three endless chains 29 by the motor 31, a number of containers 15 are displaced from the loading zone. 33 to the unloading zone 28 in the loading station 10. The bases 18 swung down at the unloading zone are moved back immedialely after unloading by means of, e.g., a pneumatically operated resetting element 35 (see Fig.2).

The method for the loading of the carriers 14 of the continuous sterilizer in Fig. 1 will now be explained in more detail. The bags 26 to be sterilized are first placed in the transport containers 15.

These transport containers are then brought from the loading zone 33 to the unloading zone 28 above the path section 27 of the conveyor 9 inside the loading station 10. The carriers 14 of said conveyor move continuously forwards below the containers 15. At an instant in time at which a moving carrier 14 is situated under a row of containers 15, the base 18 of the transport containers is swung aside and the plastic bags 26 fall precisely into the compartments of the respective carrier 14.

In the method illustrated in Fig. 2 three chains 29 of transport containers 15 situated in parallel next to each other are used. According to this method, which is indicated solely by way of example, three carriers 14 are always filled by the transport containers 15. Owing to certain circumstances such as described in the related patent application no. (855122), a carrier 1 4 may be absent at one or more points in the conveyor. If the empty point is situated under one of the transport containers 15, a detection element 34 comes into operation (see Fig. 3) and the magnetic Lock 25 remains closed so that the bags 26 are not unloaded. The use of three chains of transport containers

15 makes sufficient time available for placing the plastic bags 26 in each container. The normal rate of movement of thirty carriers 14 per minute can be maintained without problems. Two seconds are then available for unloading and four seconds for loading and displacing the transport containers.

Claims

Claims 1. Method for the loading of a continuous sterilizer for Liquids packed in plastic bags (pouches), the sterilizer being composed of a treatment chamber through which an endless conveyor moves which, outside said chamber, traverses a cooling section, an unloading station, a loading station and a heating section, which conveyor is equipped with trough-shaped carriers, arranged transversely thereto, provided with compartments, situated in line with each other, which are each suitable for receiving, transporting and discharging again a bag to be sterilized, characterized in that the bags to be sterilized are first placed one by one in a row of transport containers which are each formed with a displaceable base, that subsequently said transport containers are brought from a loading zone to an unloading zone situated inside the loading station above a horizontal path section of the endless conveyor with Its carriers and that the base of each transport container is then swung aside at an instant In time at which a moving carrier is located under the containers.

2. Method according to Claim 1, characterized in that at the loading zone the bags are placed in a number of rows of transport containers, situated in parallel next to each other, which are simultaneously moved from the loading zone to the unloading zone .

3. Method according to Claim 2, characterized in that three parallel rows of transport containers are used, each row being assembled into an endless chain which then advances, together with the two other rows, intermittently in one direction.

4. Continuous sterilizer for the heat-treatment of liquids packed in plastic bags, comprising a treatment chamber provided with heating means, further comprising an endless conveyor for the bags, which conveyor traverses a loop-shaped path inside said chamber and, outside th.ereof, a cooling section, an unloading station, a loading station and a heating section, the conveyor being equipped with trough-shaped carriers, arranged transversely thereto, provided with compartments, situated in line with each other, which are each suitable for receiving, transporting and again discharging a bag to be sterilized, characterized in that the loading station (10) is provided with at least one endless chain (28) constructed from a row of transport containers (15), connected pivotably to each other, which can each receive a plastic bag, which chain is provided with a drive (31 ) for a stepwise displacement transverse to the direction of movement of the conveyor (9) in the Loading station, and that means are present for the unloading of the transport containers above a carrier (14).

5. Continuous sterilizer according to Claim 4, characterized by a detection element (34) in the unloading position under the conveyor (9) in the region of an endless chain (28) of transport containers (15) such that if a carrier (14) is absent, a magnetic lock (25) can hold up the unloading of the transport containers.

6. Transport container to be used in the method according to one of the Claims 1-3 and in the sterilizer according to Claim 4 or 5, characterized by an oblong, in cross section U-shaped, construction with two upright side walls (16, 17), a base (18) which can be swung down wards and a length corresponding to a single compartment of the carriers of the continuous sterilizer.

7. Transport container according to Claim 6, characterized in that all three component parts are formed from sheet steel and consist of: a first side wall (16) folded into a J shape in cross section, a folded second side wall (17) with an S-shaped profile in cross section, and a base (18), which is also folded, with a longitudinal edge (20), bent over at right angles, provided with fixing elements (21), constructed with increased thickness, for a pivoting shaft (22) which is mounted in a supporting element (23) accommodated in a recessed part of the S profile.