| 摘要 |
<p>A gas-tight seal module (6) is incorporated in a trocar system to form a gas-tight seal about an instrument (12) inserted into the cannula of the trocar system. The module (6) incorporates an apertured disc (30). The aperture in the disc can be stretched to accommodate a seal about an instrument (12) inserted into the cannula. The disc is carried by a flaccid membrane (20) which extends across the module (6). A pair of rigid washers (32 and 34) clamped on opposite sides of the disc (6) are constrained for movement between two parallel spaced surfaces. The disc is thus freely moveable in its own plane to accommodate off-axis movement of the instrument so avoiding the breakage of the seal with the instrument which would otherwise occur if the disc did not have the same freedom of movement. The disc (30) also acts to clean the surface of the instrument when withdrawn so as to avoid contamination of a flap valve (10) upstream of the disc (30).</p> |
