Abstract: A constant gas flow regulating device includes an inlet chamber, an outlet chamber and a movable wall that delimits the inlet and outlet chambers from each other. The moveable wall carrics a body comprising an opening that permits communication between the inlet and outlet chambers. An elongate element extends centrally in the opening of the body in the moving direction of the wall. The opening within the body surrounds a portion of the elongate element. In a first position the opening in the movable wall is placed in the vicinity of a first end of the elongate element. The element has a sectional size that gradually increases from the first end to a second end thereof. The size of the opening in the movable wall is larger than the sectional size of the elongate element. A helical spring biases the movable wall towards a first position.

Abstract: An injection device is provided for a continuously variable metering and administering of a liquid preparation and having a holder device for a multi-dose injection cartridge, the rear piston of which may be moved forward by means of a piston rod. The piston rod is provided with releasable locking means having at least one longitudinal groove having a wedge-shaped cross section and at least one locking lug having a cross section adapted to that of the groove, and means for urging the locking lug into said grooves to lock the movement of the piston rod, or to release the locking lug from said groove to free the movement of said piston rod. At its rear end, the piston rod is connected to a spring device for moving the piston rod forward and to a device for determining the stroke of the piston rod when the preparation is administered.

Abstract: Apparatus for simultaneously adding liquid to a test tube and agitating the resulting contents consists of a mounting for a pipette to discharge liquid into the test tube, with a vibratory agitator also supported by the mounting, and having its lower end extending into the test tube below the level of the pipette.

Abstract: A device for removing liquid from a test tube consists of an evacuation tube having a flexible plate extending outwardly from its lower end, the plate having a number of radial grooves connected at the center, so that by pressing the bottom of the test tube against the flexible plate, moisture can be removed by suction applied to the evacuation tube.

Abstract: A dosing device for dispensing very small quantities of liquid includes a variable displacement piston for varying the pressure within a chamber and valves located in inlet and outlet ducts communicating with the chamber. The valves preferably comprise a disc having a circular periphery and including passages therein which are radially spaced from the central portion of the disc. This central portion engages a valve seat to close off the corresponding duct and is preferably rigid to prevent permanent deformation of the disc. The peripheral edges of the disc are received in an annular groove and are free to move radially therein.