Fluent material handling – with receiver or receiver coacting mea – Processes
Reexamination Certificate
2002-01-04
2003-07-22
Huson, Gregory (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Processes
C141S094000, C141S146000, C141S152000, C141S324000, C222S168500, C222S305000, C222S440000
Reexamination Certificate
active
06595245
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to metering products, in particular liquid product, and to filling containers with the metered products.
DESCRIPTION OF THE PRIOR ART
In many production fields, e.g. the chemical-pharmaceutical industry, food, cosmetic and other industries, containers, e.g. bottles, must be filled with a metered quantity of products, in particular a liquid product.
According to regulations in force in different countries, a predetermined minimum nominal net weight, as well as a predetermined difference margin, should be indicated on the package.
Many solutions have been heretofore used in different machines for metering liquid product and for filling the containers.
According to one of the known methods, a constant volume of liquid product, obviously corresponding to the required nominal net weight, is determined considering the product density.
The metered quantity of product is introduced into the containers by suitable delivering means, e.g. nozzles.
The container is weighed before the filling and after the filling, in order to control if the metered volume is constant and to define tare and gross weights.
The values obtained by the above mentioned weighing operations are processed by a suitable electronic unit, which calculates the effective net weight of the liquid product introduced into the container.
If the obtained effective weight of product is lower than the minimum acceptable weight, suitable additional delivering means introduce another portion of liquid product, constant or proportional to the error entity.
However, according to this solution, the final weight of the liquid product introduced into the container is not measured again, therefore, the volume of the introduced product is not guaranteed.
One of the disadvantages of the known machines derives from the inevitable wearing out of liquid delivering means and the feeding means joined thereto.
This results in the need of further volume correction, e.g. by introduction of another quantity of liquid through the above mentioned additional delivering means.
Analogous problems of volume variation are connected with possible temperature variations, particularly if the product density is considerably influenced by the temperature.
According to another known method, the containers are filled until a predetermined level by delivering means provided with suction means working in the area of the filling level.
However, this solution does not guarantee a constant volume in case of containers having different cross sections.
According to still another method, the liquid product is delivered in two subsequent steps.
During the first step, the containers are filled with a relatively high speed, but not completely, while during the second step, the containers are filled slowly until the predetermined net weight is obtained.
The apparatuses carrying out the above mentioned method are usually rather complicated and their working time is long.
These apparatuses usually include a plurality of working groups, which weigh, in time relation, the containers, so as to determine the tare weight, and deliver liquid products.
The Belgian Patent No. 901.407 claims a method for filling containers, which includes measuring the tare weight of the single container, in a first weighing station; transferring of this container to an initial filling station, where the product is delivered until 90% of nominal net weight is obtained; measuring of the gross weight of the partially filled container in a second weighing station; transferring of the partially filled container into a final filling station, where the filling is completed by delivering an additional quantity of product, which is determined by processing means, supplied with data obtained by the above mentioned measuring operations.
However, this method does not include controlling of the additional quantity of delivered product, therefore, it is not possible to correct possible variations deriving from e.g. problems of the delivering pump.
According to yet another method, a liquid product is delivered to the containers for a predetermined period of time, at a constant flow rate, so as to deliver a quantity of liquid products proportional to the delivery time.
The above mentioned method is carried out by machines, which include a liquid feeding reservoir, inside which there is pressure realized by a suitable gas.
A feeding channel, extending from the reservoir, has a delivery nozzle at its end and is equipped with a valve means, which is activated by timer means.
The drawbacks of this solution derive from the lack of precision resulting from a gradual reduction of level in the feeding reservoir and from a consequent variation of the delivery pressure, which influences the flow rate.
This disadvantage is sometimes outweighed by gradual increase of liquid delivery time, however, it does not guarantee the introduced quantity, since the weight of the product really introduced into the containers is not determined.
There are also other methods, different from the just described, or combining some of their characteristics.
The Italian Patent application No. 3546A/87 claims a method for batching products by subsequent corrective deliveries in relation to weight checks, which includes the transferring of the containers through subsequent delivering stations, alternate with weighing stations. In each delivering station an additional quantity of product is delivered in relation to the weight check carried out in the previous weighing station. In the final delivering station, a further correction is carried out, some quantity of product is added or taken away, depending if the final obtained weight is smaller or bigger than the nominal one.
The U.S. Pat. No. 5,156,193 claims a method for filling containers, which includes: measuring of the container tare weight in a first weighing station; filling of this container with liquid product in a delivering station; measuring of the full container weight in a second weighing station; processing of the data coming from the above mentioned weighing stations, as well as of the data concerning the pressure and temperature of the delivered products, in order to determine the delivery time necessary for filling the subsequent container up to nominal net weight within an acceptable variation.
The German Patent No. DE 2660164 discloses a method for metering liquid product, which uses a metering container submerged in the liquid to be delivered to the containers, inside a suitable reservoir.
The metering container moves vertically, so as to engage, during its upward stroke, a perforated plug, which communicates axially with a nozzle connected to a liquid product discharge pipe.
The inner volume of the metering container defines the metered quantity sent to the container, as a consequence of the relative movement between the metering container and the plug acting as a piston.
However, this solution features considerable drawbacks resulting from tightness and wear of the parts which are in contact with liquid product, in particular the nozzle.
Consequently, different methods used so far for filling containers with liquid product and the like, usually require complicated machines, because of the presence of a series of weighing stations and a series of delivering means, which results in higher maintenance costs, in particular for cleaning and substitution of worn parts.
Moreover, these machines usually do not guarantee the metering precision.
Another disadvantage of the above mentioned machines is encountered during change over operation, which requires change of the metered quantity of products. The change over usually requires complicated operations for replacement of the parts involved in the filling process.
According to a device known in the art, shown in
FIGS. 1
to
4
, a reservoir
3
is fed with the liquid product
10
to be introduced into containers
2
. The reservoir
3
is periodically supplied by a suitable supply duct
4
, so as to maintain constantly the product level within the range defined by sensor means
Coleman Sudol Sapone P.C.
deVore Peter
Huson Gregory
Sapone William J.
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