The invention relates to a device and a method for dosing foamed compounds. A device of this type is, for example, used in the manufacture of a consumable product, in particular for filling and free-finishing foamed, pressurized compounds. Generally, the foamed compounds to be dosed are viscous compounds from the field of food products, adhesives, insulants, etc. which, in the dissolved, melted or softened state, have been foamed up with a gas and are dosed to a target location via a pump and nozzle system and subsequently harden.
In known filling systems, the filling amount of compounds of this type is filled or free-finished in a time-controlled manner via open/close valves or via ram dosing pumps. The compound is supplied to a container (collector), which is embodied in a compression-proof manner, generally via one to two pressure lines.
On the one hand, ram dosing pumps do not provide the required speed; on the other hand, the foamed-up compound expands between the dosing ram and the nozzle outlet. This has the consequence that the compound drips at the nozzle outlet and the filling precision is reduced. During dosing by means of time-controlled valves, the flow conditions in the container, which is embodied in a compression-proof manner, do not permit a precisely defined pressure over the entire system up to the nozzle outlets. This also results in imprecision in the filling volume. Furthermore, withdrawal, and thus a precisely defined break-off, of the compound is not possible.
The problem of the present invention is to develop a dosing device and especially a pump system in order to improve filling precision, to increase the speed of the pumping process and the entire filling/finishing process, to prevent dripping at the nozzle outlet and to ensure clean breaking-off of the dosed compound.
The problem is solved, in terms of the device, by the features of claim 1 and, in terms of the method, by the features of claim 10.
Advantageous developments emerge from the dependent patent claims. The advantage of the invention consists in the fact that the predefined pressure in the compound can be kept constant up to the nozzle outlets. The filling precision is increased as a result of the supplying of each (retractably closable) nozzle with a pump and the synchronization of all the pumps. The use of a rotary ram pump, a gear pump or the like obviates the need for an intake stroke which is necessary in ram dosing pumps and increases the overall cycle time. An advantage of the invention results from the use of rotary pumps which are coupled to one another and jointly form a pump unit. This produces exactly the same amount of compound (for example foamed consumable product) for each nozzle. The rotary pumps are supplied with free-flowing compound via a compression-proof container.
A further advantage of the invention results from the use of a slip clutch which mechanically, electromechanically or magnetically connects the drive motor to the pump unit. The drive motor can also be fixedly connected to the pump unit. In this case, the torque is controlled electronically. It is also possible to use an air or hydraulic motor and to set the torque via the air or oil pressure. The torque at the pump unit is set in such a way that, during and after the flowing-out process, the required pressure in the compound is kept constant up to the nozzle outlet. This prevents the compound from expanding before the nozzle outlet.
A further advantage of the invention results from the use of pull-back rams which are integrated in the closure mechanisms of the nozzles and prevent the compound from dripping after the filling and finishing process. Once the nozzles are closed, the pull-back rams are pulled back in synchronization. As a result, a portion of the compound remaining in the nozzle outlet is drawn into the cylinder space of the pull-back ram and clean breaking-off of the compound without dripping is ensured.
The invention will be described in greater detail based on an exemplary embodiment which is to be interpreted in a non-restrictive manner and is illustrated in the drawings, in which:
In a device for making a consumable product from a free-flowing, especially foamed compound, for example a consumable confectionery product, the free-flowing compound is located in a container (1) which is preferably embodied in a compression-proof manner and the outlets (2) of which open into intercoupled rotary ram pumps (3). The volume flow is synchronized as a result of the coupling of the rotary ram pumps (3). The outlets (4) of the rotary ram pumps open into nozzles (5), before the outlet openings of which a respective closure mechanism (6) is located. The closure mechanisms (6) are opened in synchronization during a defined time window. In this way, the compound can be dosed in an exact manner. Each closure mechanism (6) is provided with a pull-back ram (7) which allows, when the closure mechanism (6) is closed, a portion of the compound located in the nozzle outlet to be withdrawn. This prevents dripping and ensures clean breaking-off of the compound. The torque which the drive (8) exerts on the rotary ram pumps (3) can be continuously adjusted in such a way that, during the flowing-out process, the predefined pressure in the compound is maintained up to the nozzles (5).
Number | Date | Country | Kind |
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0125/07 | Jan 2007 | CH | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP08/00447 | 1/22/2008 | WO | 00 | 2/22/2010 |