Chemical apparatus and process disinfecting – deodorizing – preser – Control element responsive to a sensed operating condition
Patent
1994-11-21
1996-04-23
Warden, Jill
Chemical apparatus and process disinfecting, deodorizing, preser
Control element responsive to a sensed operating condition
422 99, 422103, 7386403, 7386411, 249180, 249184, G01N 114, B01L 300, B01L 302
Patent
active
055100830
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a pipetting aid for exerting suction on and emptying of liquids in pipettes and a production process for this pipetting aid.
A multitude of pipettes are known from the prior art, which exert suction on liquids and squeeze them out by means of a piston mechanism. Only a few technical solutions however are known for pipettes which are still frequently used in laboratories as simple, cheap and easy to handle measuring devices and in which the exertion of suction is carried out by mouth or with a rubber ball (the pipetting aid), which can be deaerated.
A suction cylinder for exerting suction on liquids in pipettes is described in DE-A-2155239, the said cylinder surrounding the end of the pipette, without valves being provided for it. A practical transposition of this suggestion is not known.
DE-A-3016594 describes a tubular pipette of fixed shape with a suction aid, the suction aid consisting of an elastic, balloon-like container part, which has a suction opening and an aeration opening lying opposite one another. The elastic and the container part of fixed shape can be fused together and consequently form a pipette with a joined suction part. The closure components for the elastic container part are not specified.
The German Utility Model GM 8333458 protects a pipetting aid for capillary pipettes, said pipetting aid consisting of a bellow-like head and a following tube for receiving an adapter for the capillary pipettes. Openings for the entry and exit of air are not provided except via the pipette tip.
A pipetting aid used under the name Peleusball is furthermore known (DE 897 930), which consists of a rubber material with an inlet and outlet each closed by a ball valve in the form of a glass ball disposed in the air passage. A disadvantage of this pipetting aid is that it is difficult to clean after pipetted liquids have entered into sections of the rubber material, and above all the necessity, when the air ball is pressed and likewise when pressing out residues from the pipette, of simultaneously having to actuate the corresponding valve with the fingers. A further disadvantage is the manufacture of at least two moulding parts with the subsequent gluing together (or vulcanization) of the material.
The manufacture of such pipetting aids is mostly effected in the injection moulding process whereby, due to the large balloon-like enlargement of the central body, either the two separately injection moulded halves are glued together or vulcanized subsequently, or a single-piece moulded body is produced in a mould without a core by means of a propellant. With the lastly named process a very irregular surface of the elastic material is produced, which, after pipetted liquids have entered, is difficult to clean.
The object of the invention is to develop a pipetting aid by using a simplified manufacturing process, which is functionally safe and easy to handle and which at the same time allows uncomplicated cleaning of the inner area.
This object is achieved according to the invention by a pipetting aid for exerting suction on liquids, consisting of an elastic hollow body with a larger ball-like central body at which are located a first tubular attachment and a second tubular attachment, from which second tubular attachment a third tubular attachment leaves at an angle, an easily removable check valve as a first closure component being disposed in the first tubular attachment, which, when the ball-like central body is squeezed, allows, without further actuation, the compressed air from inside the hollow body into the outer atmosphere, but not vice versa and at the same time the second and third closure components in the corresponding attachments substantially adopting a position which prevents air from passing from the inside to the outside. When the air is compressed, the check valve therefore adopts a through passage position, whilst having a closed or locked position when only low pressure is in the lower central body.
The check valve is a cylindrical body in which at least one cylinder ar
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Breskamp Michael
Ehinger Karl-Heinrich
Sack Helmut
Deutsch & Neumann GmbH
Schuman Jack
Soderquist Arlen
Warden Jill
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