Tube filling machine (2)

Tube filling machine

The tube filling machine, also known as a tube filler, is a special packaging machine for filling and closing tubes. They are used to fill a variety of low to high viscous products of pharmaceutical, cosmetic, food, chemical, or other industries into tubes.

Old Tube Filling Machine from GDR (TUFÜMA 50)
Empty unclosed tube from pharmacy in Kassel, Germany
Semi-automatic tube filling machine TU25 from Gustav Obermeyer
Device for manual filling of tubes. Exhibition piece of the German Pharmacy Museum in Heidelberg, Germany.

General Information

The degree of automation (manual, semi-automatic, and fully automatic) depends on machine performance and feeding of containers, as well as the requirements at the filling and closing process. The main work units of tube fillers are generally tube feeding, tube orientation, tube filling, tube closing, and tube output. Tube filling machines have been built since the turn of the century. The German manufacturer IWK based in Stutensee near Karlsruhe is often called the "inventor" of tube filling machines. The actual date of their company foundation was in 1883. In recent decades, there is only one further German manufacturer named^[1] who was founded in 1889. In times of GDR, Gustav Obermeyer was responsible for the manufacturing of tube filling machines within the Council for Mutual Economic Assistance (Comecon).

Principles and structure

Tubular fillers are among the most mechanically complex machines in which different functions are combined in an extremely small space. Today, there are two main types of construction principles which should be mentioned in particular: the rotary indexing machine with a clocked turntable for tube transport to the individual stations, and the oval machine where the format holders for tubes are placed on a chain. This chain moves in an oval shape to individual working stations. Tube filling machines can be driven pneumatically, electrically by stepper motors or servomotors, and/or mechanically by means of cams. The main structure of tube filling machines consists of: input of empty tubes, alignment according to the printed mark, supply of filling product, filling station, closing of filled tubes, tube embossing, and dispensing. Supplementary stations can include tube cleaning, barcode readers, nitrogen fumigation, labeling, and other special requirements.

Tube feeding

Depending on the required performance, several tube feeding systems besides manual input are used. There are tube input magazines for in-delivered carton sizes and tube feeding elevators with a large storage capacity, or complex feed systems with robot technology. From the feeding magazines, the empty unclosed tubes are inserted into the tube holders, which are, in general, format parts.

Tubes orientation

Before filling, tubes are aligned so that they are properly and equally orientated by the printing mark. The printing mark is normally placed on the upper end of the tubes. The upper end is the opposite side of the tube closure. The mark is detected by a sensor which checks the right alignment of the tubes. In general, on PE-tubes, you can see the printing mark, while on filled and closed metal tubes, the printing mark is hidden by the fold.

Product feeding and filling station

Tubes can be filled with a variety of products of different viscosities like toothpaste, cosmetic creams, shampoo, sun projection, a multitude of ointments for the pharmaceutical industry, UV gels, polishing pastes, paints, glues, shoe polish, sauces, pet food, and much more. Due to that high variety of products, different requirements are given for the filling station. The most common used filling and dosing technology for tube fillers are reciprocating pumps. The product will be stored in a container e.g. in hoppers. From there, product is aspirated by the dosing unit which consists of a dosing piston and cylinder. If the dosing unit has reached its reversal point, the rotary valve turns and opens the way to the filling piece by closing the way to the product hopper. The filling piece finally fills the empty tube with product. Most manufacturers raise the tubes under the filling piece before filling in order to be able to lower them during the filling process in terms of better filling quality. A special filling technique is the two colors or striped filling which is well known in terms of tooth paste. There are two main distinctions. First is the striped product when pressed out of the tube where the stripes are only on the outer surface shaped due to the geometric inner design of the tube.^[2] The product for the stripes is placed in the bottom part of the tube and the main toothpaste material is filled in the upper part of the tube. Second, there is also the possibility to fill the tube with two colors or more in form of stripes or several product layers. Further equipment for the product feeding could be warm filling with a heating jacket or double walled hoppers, agitators and product level control in the hopper. There are also other filling and dosing solutions like rotary piston pumps, progressive cavity pumps or filling by flow measuring.

Tube closing

Depending on the material of the tubes, they are either sealed after filling (plastic or plastic laminate) or folded (aluminum). When sealing, the proven and advanced hot air technology is usually used. In general, the plastic on the upper tube ring is heated by hot air so far until the melting point of the tube material. Right after, the tube end is pressed together where the heated plastic layers fuse to a tight tube sealing. There are also alternative sealing methods for PE-tubes like hot jaw sealing or closing by laser or high frequency technology.

Metal tubes are closed by folding. The form of folding determines the number of folding stations. Common folds are the double fold, triple fold, and saddle fold. It usually can only be for triple and saddle fold double-sided embossing used due to needed fold thickness.

Embossing and cutting the tubes

Like customer wishes, tubes can be signed by embossing with date, serial or batch numbers, or other lettering. There are single-side or double-sided embossing. Embossing for PE-tubes, the digits are elevated, while digits by metal tube embossing are deepened. Plastic tubes are cut after the sealing and embossing stations for clean tube closure and for improved aesthetic value. In addition, the corners can be rounded off or a curved seam can be created. In the chemical industry, the so-called "Euro hole" is often stamped into the sealed seam in order to be able to hang the tubes in the shop at sales displays. The resulting snippets are collected into a collecting container.

Output

The last station is the tube output where tubes are ejected from the tube holder on a slide and/ or conveyor belt. Tubes can be ejected with the fold/sealing ahead or with the cap ahead. There is also the option to eject faulty, not filled tubes separately. In general, filled and closed tubes are finally packed after the output of the tube filling machine e. g. in a folding box, tray, or carton.

References