CS264178B1 - Sucking and dosing apparatus for liquids - Google Patents

Abstract

The essence of the solution is that it is inefficient space in the supply pipe and space between the working piston and the working cylinder is filled with aspirated liquid behind by a displacement element. The device is can be used in the construction of suction and dispensing pipettes and micropipettes of one- multichannel with work design single use cylinder.

Description

The present invention relates to a suction and dosing device for liquids.

Hitherto known solutions to the problem of displacement of the inefficient space of the liquid suction and dispensing devices only partially solve this problem, by destroying the manufacturing tolerance between the piston and the working cylinder of the plunger-type pistons without sealing, or fitting the end of the piston with a seal. A disadvantage of the plunger-type piston is that the device becomes functionally unsuitable after wear of the piston or the working cylinder wall. While sealing the plunger with a cuff, the seal is satisfactory, but for small piston diameters it is technically very demanding and operationally vulnerable. In both ways, the device is very sensitive to the tapered defect of the working roll, which is believed to be made of high surface quality from materials that guarantee the exact geometry of the roll, e.g. glass. However, both of these methods do not solve the dead space problem in the feed line, causing considerable operational unreliability and dosing inaccuracy.

These disadvantages are overcome by the liquid aspirating and dispensing device of the present invention, which fills inefficient space in the feed line and in the space between the dispensing working piston and the working fluid sucked by a solid geometry displacement element that moves in a cylindrical cavity with elastic The air from the inefficient spaces is concentrated into the cylindrical cavity below the expulsion element, which upon completion of the dispensing removes liquid from the inefficient spaces of the device by overpressing the air vial which expels the expulsion element from the cylindrical space. When displacing the inefficient space with the working suction liquid and expelling it from these spaces, it is assumed that the working dispensing piston is fully inserted in the working cylinder.

If we mechanically ensure that the piston face only moves in the working fluid, we achieve a reliable function of the suction and dosing device for the next suction and dosing of the fluid by moving the working piston in the working cylinder. The sealing of the piston against the displacement element is provided by a sealing ring located in the ¹ recess of the displacement element.

The displacement of the inefficient space and the sealing of the piston of the suction and dosing device does not require a strict cylindrical shape of the working cylinder and does not require direct contact of the piston with the working cylinder. As the working fluid occupies a full inefficient working space, the suction and dosing device with displacement element approaches the ideal free-flow plunger-type device without inefficient spaces. This results in high accuracy of dosing and suction of the working fluid. The simplicity of the construction of the displacement element and its sealing against the working piston by the primase sealing rings at least the cost of repairing the device due to its leakage in exchange for a new sealing ring. The device does not require a cylindrical shape of the working cylinder nor a high quality of its surface.

In the attached drawing, two axial sections of the suction and dosing device are shown with the working piston fully inserted. In FIG. 1 shows the device in a rest position, FIG. 2 is a device after the inefficient working space has been displaced by a liquid.

An example of an embodiment of the suction and dosing device is in the attached drawing. The device consists of a working cylinder 1, in which a generally non-cylindrical working space 8, a cylindrical cavity 4 and a feed channel 3 are formed. In the cylindrical cavity 4 made of elastic material, a rotatably rigid displacement element 5 is provided with sealing ribs 6. and by an elastic sealing ring 7. By moving the displacement element 5 towards the face 12 of the working cylinder 1 in the cylindrical cavity 4, the inefficient working space 9 is filled with working fluid 10 from the container 11 through the supply channel 3. The working piston is fully inserted into the working cylinder. Further lubrication is performed by moving the piston 2 towards the face 12 of the working cylinder 1, taking care to ensure that the face of the piston 13 boto below the level of the level 14.

The liquid suction and dispensing device with displacement element can be used in the construction of suction and dispensing pipettes and micropipettes, both single and vane, with increased demands on the accuracy of the dosing quantities. In the construction of the working cylinder it is possible to utilize transparent plastic masses in full width, which enable optical control of the level of sucked and dosed liquid, correct function of the device and especially the construction of the working cylinder suitable for single use with minimal feed channel length.

SUBJECT

The liquid suction and dosing device consists of a working cylinder closed at the bottom by a supply line into which the working dosing piston is slidably inserted from the front, characterized in that the working cylinder (11) has an elastic cylindrical cavity (4) on its front side.

Claims (1)

wherein a stiff displacement element (5j) with sealing ribs (6) and an elastic ring (7j) is provided with an interference fit, a cylindrical working piston (2) on which the displacement element (5) is displaceably supported. 1 shows a drawing of FIG. 1, FIG. FROM Severography, a. p., plant 7, Most