ON/OFF VALVE

摘要

A manually operated on/off valve includes a plastic-moulded box (1) with an inlet (2) and an outlet (3) and an essentially cylindrical opening (4) with an embedded rotary shut-off device (5) of plastic. In the first shut-off device (5) position, a flow from the inlet to the outlet is prevented, and in the second position, a flow from the inlet to the outlet is allowed via a passage (6) in the shut-off device (5). Such a valve forms part of, for example, medico-surgical drainage systems where the valve can be operated by the user/carrier. To ensure that the valve is completely tight when it is to prevent a flow from the inlet (2) to the outlet (3) as well as at the ends of the opening in the valve box (4) serving as the bearing of the shut-off device (5), according to the present invention it is suggested that at opposite ends the cylindrical opening (4) in the box is provided with an outward-facing conical surface (7) designed to interact with a corresponding conical surface on the shut-off device (5) where the shut-off device is embedded by means of a process and/or of a material causing the shut-off device (5) to shrink more than the box (1) upon cooling and causing cross sections of the box opening (4) to deviate from a circular form in such a way that the extent of the shut-off device (5) at right angles to the passage (6) is slightly larger than in the direction of the passage. When the shut-off device (5) shrinks upon cooling, its conical surfaces will be pressed against the corresponding surface (7) in the cylindrical opening, thereby achieving a particularly good sealing at the ends of the opening. Because of the deviation from the circular form, the shut-off device embedded in the opening does not have circular cross sections either, but in the closed position is pressed tightly against the orifices of the inlet and outlet in the box opening to prevent leakage along the exterior of the shut-off device.