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Tubular pump

Tubular pump description/claims

The present invention relates to a tubular pump which has outstanding features of novelty and inventive step.

In liquid metering technology, for example in pharmaceutical or other fields, it is necessary to use pumps which can meter various types of liquid, gel or the like with great precision, while achieving excellent asepsis and operational reliability. Furthermore, the quantities to be metered in each cycle must be able to be easily varied.

Different types of mechanical pumps are known at present, for example piston pumps in which liquid is metered by the positive movement of a piston, combined with a valve system for supplying and discharging liquid and with different means for varying the quantities metered in each cycle. Also known are systems in which other types of pump are used together with inlet and outlet control valves, including in some cases storage receivers situated before the metering conduits.

Said types of pump known at present have a number of drawbacks which hinder their use and make their practical application more expensive. Firstly, account must be taken of the difficulty in cleaning the pump and the valves thereof when changing the liquid to be metered, this being an awkward and relatively unsafe task from the point of view of asepsis. There are also problems of reliability, as the pumps are basically mechanical pumps, thus implying a large number of parts which could suffer damage, wear, etc. Among the drawbacks of pumps which are known at present, account must also be taken of the inevitable contact between the liquid and various materials, in many cases metal materials, which is also disadvantageous for some types of liquid to be metered.

Another type of known pump is the peristaltic pump in which a compression element thoroughly compresses a tubular element which is full of liquid to be pumped, moving along a variable portion of the tube, thereby causing the positive displacement of the contents of the tube and the pumping action. However, a major disadvantage of these pumps is the complete mechanical collapse of the tube, which accelerates the ageing thereof and detrimentally affects the integrity of the metered product, since in many cases some molecules of the product can suffer damage due to compression. Further disadvantages of peristaltic pumps are the unsatisfactory dose repeatability and the high dependency of the metered quantity on the precise path of the roller or rollers, since in many cases the final positions are not entirely precise, thereby affecting the repeatability of the dose.

Taking into account the prior art, the inventor has carried out a plurality of tests and investigations to produce a pump which overcomes, at least substantially, the earlier drawbacks. The inventor's research and tests have resulted in the production of a tubular-type pump which has original features and which provides superior quality in terms of asepsis, constructional simplicity and reliability.

Basically, the new tubular pump is based on the use of a tubular element made of resilient material, such as for example rubber, PVC, silicone, etc., for containing liquid which is to be metered and which travels in an intermittent and controlled manner through the tube as a result of an action of transverse compression thereof, which is converted into a pumping of liquid contained in the tube by combination of said action of transverse compression with a liquid inlet valve which will be closed during compression and a liquid outlet valve towards the receiver to be filled which will open during compression. When the action of compression transverse of the tube is complete and natural recovery thereof has been made possible by its own resilience, the inlet valve will be open to allow the new liquid to enter and the outlet valve will be closed to prevent the unchecked discharge of liquid towards the receivers to be filled. The action of compression preferably takes place between a lower surface or planar die and an upper planar ramming member, in such a way that, for a given tube, the quantity of liquid will vary with the compression stroke and the length thereof, since, once compressed, it will represent the decrease in volume of the tube from its original shape with a circular cross-section to the final shape in which it will adopt the shape of a rectangle with plane parallel sides and ends in the shape of semi-circumferences with diameters equal in size to the smaller side of the rectangle. Given the resilience of the tube, recovery of the original shape after each compression cycle, i.e. metering, is ensured.

The precise section of the tube can also be varied by the drawing thereof, which will be a means for varying the quantity of liquid provided in each compression cycle of the ramming member.

The pump will be able to comprise a plurality of tubular elements for the simultaneous metering of various lines with an identical or different product, and with likewise variable doses, making it possible to fill different receiver lines or supply different liquids to the same receivers of a given container line. The new pump can therefore be used in a very versatile manner.

The tube can be made of a single part from the initial receiver to the final destination; and this makes cleaning the pump very easy and safe.

Excessive stroke values are not required for the pump to operate properly. On the contrary, one significant feature to take into account is specifically that the transverse compression level of each tubular element in the pump will be very moderate and, once the tube is distorted to a limited extent, this allows for extraordinarily long-term operation of each tube while maintaining the operational features thereof.

One of the applications of the pump according to the present invention is filling the receivers with cards for clinical analysis in which the micro-receivers of each card will be able to receive the different products in a liquid or gel state in order to fulfil their function.

One example of a pump according to the present invention will comprise three successive units which have a similar structure and which are synchronised in their operation, one of them having, for metering, a planar base for receiving the flexible and resilient tubular element and a compression ramming member, likewise planar, actuated by any appropriate means, for example hydraulic, pneumatic, electromagnetic means, etc., in order to compress the tubular element, its downward stroke being well-controlled, preferably by fixed stops, in such a way that compression of the tubular element will be very precise and smooth. An initial unit and a final unit of the three-unit assembly of the pump will be for completely closing the tubular element, which operates as a uniflow valve, and the intermediate unit will be for carrying out the compression for the metering of the product. Fixing the tube or tubes corresponding to the compression unit will allow possible drawing of the tubes, in order to adjust the metering of each individual action of compression. In order to allow a decrease or increase, the metering tubes can have an initial drawing which can be increased or decreased.

As will be appreciated, the product inlet and outlet valve units can be produced by any technically appropriate means, production thereof preferably being by means of a base assembly for receiving the tubular supply and discharge element and a ramming member to compress the tube until it closes. As is obvious, the tubular elements of the valve units may differ from the tubular metering elements, having appropriate flexibility and being easily changeable. Furthermore, the structure of the base and compression ramming member for closing the tubes by joint action between the two may vary substantially since, although the base and ramming member may be planar, a curved base and/or pointed or otherwise shaped ramming member can also be used, providing that enough compression can be exerted on the tubular element for complete throttling thereof, thereby closing it.

Operation of the pump will be cyclical, actuating in a successive manner, after the initial filling of the tube, the inlet closure valve, the metering element for partial compression of the metering tubes and the outlet valve which will allow the pumped quantities to be metered. An electronic assembly will control the metering pump as well as reversing the direction of passage of the products to be metered. To simplify assembly, should the conditions necessary for the product allow it (in terms of metered volume, desired accuracy, product features), non-return valve assemblies can be used, advantageously eliminating the need for synchronisation.

For a better understanding, an embodiment of the present invention is illustrated, by way of an explanatory but not limiting example, in the accompanying drawings in which:

FIG. 1 shows schematically the basic principle of operation of the pump according to the present invention.

FIG. 2 shows a schematic perspective view of an embodiment, by way of example, of the pump according to the present invention.

FIG. 3 shows a front elevation of the pump in FIG. 2.

FIG. 4 shows a plan view of the same pump as in FIG. 2.

• Provisional Patent
• Utility Patent

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