| 摘要 |
<p>A resiliently compressible variable volume casing having particular application as a disposable syringe. The casing (1) defines a chamber (1a) and is provided at one end region thereof with an aperture (2) for permitting transfer of a substance to and from the chamber. The casing is in the form of a bellows and has a wall including a plurality of fold regions (6) between which are respective bellows portions (7, 7a). The casing is configured so that there is a substantial reduction in ''dead space'' or the air entrapped in the casing, when the bellows is compressed. This is achieved by one or more of the following: 1) forming the bellows portions so that when the bellows is compressed there is a bellows portion the periphery of which lies wholly within or wholly without the peripheries of its adjacent bellows portions; 2) providing the casing with a member mounted with respect to the casing and such that, when the bellows is compressed, the member occupies a major portion of the internal volume of the casing; and 3) forming the bellows portions each with concave and convex surface so that a concave surface of one bellows portion mates with the convex surface of the adjacent bellows portions. The reduction of ''dead space'' in the compressed casing, and the almost complete elimination of air which follows, mean that the casing is particularly useful for the storage of substances for which contact of air is to be avoided. The aperture may be formed as a hollow needle receiving portion particularly adapted to receive a hypodermic needle, so that the casing may be used as a syringe either to remove body fluids or to administer medication.</p> |
