Pressure transmission device

The present invention relates to an apparatus for transmission the pressure in the sterile area of ​​a medical Device on a non-sterile pressure gauge. Such pressure transmission devices for example in hemodialysis, Heart-lung machines and similar medical Devices are needed in which a very accurate monitoring the pressures prevailing in a sterile tube system is required at the same time but a sterilization the corresponding pressure gauges is impractical.

This pressure transmitting devices have absolutely tight and be leak-free, thus not sterile air into the sterile area enters the medical device or the pressure reading is falsified. In addition, these pressure transmission devices must at the non-sterile side a so-called "Luer-Lock" connection from a polyester / polyether copolymer have, because only with such a connection a slightly separable and nevertheless absolutely leak-free connection with the corresponding stainless steel connecting elements of pressure gauges is made possible in the medical device.

The previously available on the market pressure transmission devices this type were constructed such that the housing from a sterile side half of polycarbonate with a constructed hose connection and a non-sterile side half was, and between those halves a web of polytetrafluoroethylene was arranged that a Polytetrafluoräthylenfolie to apply pressure while complete tightness contributed. The corresponding non-sterile side "Luer lock" -Anschlußvorrichtung had it in the preparation the non-sterile side half of the housing in a separate Injection molding process are subsequently injected. Experts believed that they could not depart from this method of preparation, as in the professional world, the prejudice existed that a completely tight and leak-free connection between a part of Polyester / polyether-copolymer and a part of polycarbonate only by consuming Zuspritzverfahren and no could be produced by ultrasonic welding. also it was believed that a fully dense mounting the fleece with Polytetrafluoräthylenfolie only between two housing halves of polycarbonate would be possible because the polyester / polyether copolymer would to be too soft.

Starting from this prior art, the object of the present invention, a pressure transmission device of the to provide the aforementioned type, the same quality (Tightness and leak freedom) much easier and cheaper to manufacture.

According to the invention the object is achieved by the fact that the nonsterile side half of the housing completely made of polyester / polyether copolymer , and the two halves are joined by ultrasonic welding.

Contrary to widespread prejudice in the art has the present invention the knowledge the subject that very probably a sufficiently tight and leak-free ultrasonic weld between a half case of polyester / polyether copolymer and a housing half of polycarbonate can be produced.

It has proven to be particularly advantageous, the Fleece which supports the Polytetrafluoräthylenfolie, polyester produce. This has the advantage of substantially that the nonwoven fabric during ultrasonic welding procedure between the housing halves is mitverschweißt, thereby significantly better Attachment and sealing of the web is achieved.

Further, it is particularly preferred that the non-sterile side Half of the housing has a thin circumferential projection, of a piece on the sterile side of the housing half overlaps and where the ultrasonic welding forms. In this way can the ultrasonic welding particularly simple, safe and cost-effectively.

Further, it is particularly preferred within the projection providing a circumferential groove in the non-sterile side half, in which a projection of the sterile side half engages. In this manner, the ultrasonic welding widened and the tightness and strength of the connection the two housing halves further increased.

It is particularly preferred thereby that the projection of the sterile side Half on its outer side a non-sterile side of the Half tapering chamfer having. hereby creates a narrow, wedge-shaped, circumferential cavity on non-sterile side end of the welding zone, in which the Dodge softened material in the ultrasonic welding can, whereby the quality of the weld continue is increased.

Likewise, it is particularly preferable that the groove at its inner side bevel. Thereby, the assembly of the two housing halves simplified and additional space for the Dodge softened by the ultrasonic welding material created.

The present invention is attached with reference to the Drawing of an embodiment explained in more detail. Show it:<sl><li><b>figure 1</b> a partial sectional view through a complete Pressure transfer device according to the invention;</li><li><b>figure 2</b> a full sectional view of the non-sterile side Half case of the pressure transmission device of the invention according to Fig. 1;</li><li><b>figure 3</b> an enlarged view of detail A of figure 2;</li><li><b>figure 4</b> a full sectional view of the sterile side Half case of the pressure transmission device of the invention gem. Fig. 1;</li><li><b>figure 5</b> an enlarged view of detail B of Figure . 4</li></sl>

As shown in Figure 1, the housing 10 consists of an inventive Pressure transmitter of a sterile side Casing half 12 with a hose connection 14, consisting of polycarbonate, and a non-sterile side Half 16 with a "Luer-Lock" connection 18, the present invention entirely of polyester / polyether copolymer consists. Between the two housing halves 12 and 16 is a Fleece 20 is pressed from polyester and by ultrasonic welding the two housing halves 12 and 16 mitverschweißt. This web 20 carries a thin Polytetrafluoräthylenfolie, the filter function between the sterile and forming the non-sterile area to a corresponding to allow air pressure transmission. The ultrasonic welding takes place between the two housing halves 12 and 16 Registered in the marked area 22.

The two housing halves 12 and 16 are each cylindrical designed so that the whole construction rotationally symmetrical is. The connection between the two housing halves 12 and 16 is achieved by doing the following in detail:

The sterile-side housing half 12 has an outer circumferential Ring 24. This ring 24 serves as a stop for a thin, circumferential projection 26 of the non-sterile side housing half 16 in the direction to the sterile side crankcase half 12 extends towards. Within the Projection 26 extends directly after this one circumferential groove 28 in the non-sterile housing half 16. In this groove 28 engages a projection 30 of the sterile side Housing half 12 a. This protrusion 30 has at its the non-sterile side half 12 facing the end of a bevel 32 on its outer side, so that the thickness of the Projection 30 on the non-sterile side half to decreases 12th

The ultrasonic welding connection is made in the experiment indicated by 22 Area from outside and peripherally. The chamfer 32 is used to create a cavity in the groove 28, in the melted by ultrasonic welding Material can escape. The inside of the groove 28 in the non-sterile housing half 16 is also beveled, order to facilitate assembly and ensure further another alternative space for ultrasonic welding to provide molten material.

Within the protrusion 30 and the groove 28, the web 20 is 12 and 16 press-fitted between the two housing halves, which the Polytetrafluoräthylenfolie for sealing the wearing sterile from non-sterile area. This web 20 is preferably made of polyester. For better fixing and sealing of the web 20 between the two housing halves 12 and 16 are on the sterile side housing half 12 two slightly protruding concentric rings 32 and 34 are provided. In the area between these two rings 32 and 34 extends from the opposite side, a further single circumferential ring 36 on the non-sterile side Housing half sixteenth

To assemble the pressure transmission device is a Nonwoven 20 with Polytetrafluoräthylenfolie into a sterile side loaded housing half, the non-sterile side housing half plugged and the two halves by ultrasonic welding around tightly connected. By this method of , the pressure transmission device significantly cheaper are produced than that of the prior art is possible.