In the current market of products for infusion, such as coffee, barley coffee, tea, camomile and the like, the use of single-dose “pods” has increased considerably and nowadays a very popular way of making hot beverages is to use such pods in specially designed machines, even for household or office use (that is, for small to medium quantities).
Normally, these pods are of the single-dose type, used to brew a single serving of the beverage. This type of pod, to which the present specification refers but without thereby restricting the scope of the inventive concept, usually consists of two portions of filter paper placed one over the other and sealed to enclose a single product dose of substantially circular shape.
A prior art packaging machine for making pods of this kind is described and illustrated in European Patent No. EP 432.126, where the pods are formed according to a process which comprises the steps of: feeding a first web or length of filter paper to a station where suitable means cause the filter paper to be wrinkled or crinkled; moving the web of filter paper along the surface of a forming drum, provided with circular pockets and with suction means which force spaced areas of the filter paper into the pockets in the drum in such a way as to form a succession of substantially circular pouches in the filter paper; filling a dose of product into each pouch by means of a dosing station located downstream of the suction drawing belt in the direction of rotation of the pouch forming drum and consisting of a second revolving drum synchronised with the pouch forming drum; and, lastly, joining the first web of filter paper, with the product-filled pouches in it, to a second web of filter paper fed at a respective sealing station located downstream of the filling station, again relative to the direction of rotation of the forming drum.
The method embodied by the machine described in the aforementioned European Patent has several major disadvantages, especially in connection with the steps of drawing the filter paper by suction to form the pouches.
Indeed, although the method includes a complex step of preparing the web of filter paper in a specific station that crinkles the filter paper to make it suitable for forming the pouches, many of the suction drawn pouches formed in the filter paper in this way are in actual fact faulty, in that they have creases or folds made in them. These creases not only prevent the infusion product subsequently filled into the pouch from spreading uniformly in the pouch itself but may also result in poor seals between the first and second webs.
As a result, the pods made are often defective and have to be rejected since they contain insufficient quantities of infusion product or have improperly sealed parts that create gaps through which the infusion product can escape.
The aim of the present invention is therefore to provide an apparatus for making pods for products for infusion that is free of the disadvantages of the prior art described above and that is capable of consistently making high quality pods.