DE102005024621A1 - Method for joining a tube to a hard part e.g. port comprises joining the tube to the hard part and shrinking a collar in the joining region of the tube and hard part - Google Patents

Abstract

Method for joining a tube to a hard part e.g. port comprises joining the tube to the hard part and shrinking a collar in the joining region of the tube and hard part. An independent claim is also included for a joint produced by the above method. Preferred Features: The inner surface of the collar is covered with adhesive to produce an adhesive joint when shrinking the collar. The join is produced by placing the tube on the outer contour of the hard part or by inserting the tube into the inner contour of the hard part.

Description

The The invention relates to a method for firmly connecting a hose with a hard part, such as a connector or a Port. Furthermore, the connection relates to a hose connection, which was produced by this method.

Want For example, from PVC existing hoses with a connector, a Port or other hard part made of an incompatible material, For example, connecting polypropylene, there are big problems, because this material combination is not weldable.

To the usual Connection method is attempted in such a connection pairing, to make an adhesive bond. Such adhesive bonds are but very expensive. Because the polyolefins are difficult to bond plastics belong, is for sufficient strength and tightness a pretreatment necessary. These usually takes place by application of a primer, by plasma treatment or by corona treatment or similar Method.

Especially the automation of such an adhesive process is difficult.

Therefore you attack frequently to the alternative of a compression of the two material pairings Applying a preload to an inserted O-ring, here used for connection and sealing. However, since medical devices, where these compounds are used, steam sterilizable have to be here is the problem that in steam sterilization, the largest part the introduced into the plastic parts bias reduced again becomes. This is the process security the connection after steam sterilization is not certain given.

A Another alternative compound consists in the so-called "insert Molding. "Here is an insert introduced. This is in an injection mold inserted and encapsulated by a plastic. Steam sterilization But here arise the same problems, which also in the injection-molding solution, the previously explained was, occur.

task The present invention is a solid compound process a hose with a hard part to give to the hand, with the one economical and easy-to-install connection is created, too is steam sterilizable.

According to the invention this Problem solved by a method having the features of claim 1. Thus, according to the invention the hose is connected to the hard part and then becomes one at heat treatment Shrinking sleeve in the connection area of hose and hard part shrunk.

By the shrinking cuff is biased. These Preload is during the steam sterilization process is not degraded because of the hose Steam sterilization stronger and begins to shrink even at lower temperatures, than all other plastic partners involved. In the steam sterilization So the shrinking process will continue. The bias is thus preserved. The case of heat treatment Shrinking cuff can be heated by any heat sources become. Here are hot air, radiation heat by radiant heater, mirror welding or the like or a laser treatment with a corresponding absorber layer in or on the shrinking Cuff or any other possible heat treatment to disposal. As a shrinking sleeve, for example, a shrink tube, as it is known in the field of electronics can be used.

Special Embodiments of the method according to the invention arise from the subsequent to the main claim subclaims.

Here It is particularly advantageous if the inner surface of the shrinking cuff coated with adhesive, so that when shrinking the Cuff results in an adhesive bond. This adhesive bond can preferably a hot melt inner layer include. The hot glue is used during heat treatment the shrinking cuff activated simultaneously. By the appropriate Hot-melt adhesive inner layer the tightness of the connection is ensured. The used hot glue has a significantly lower melting temperature than the two connection partners, for example, polyvinyl chloride and polypropylene. When shrinking the Shrinking cuff melts the adhesive layer and formed a tough one elastic mass stuck by the shrinking polyolefin shell pressed into every bump and held there until the material is solidified again. hereby results in an airtight and moisture-proof connection against 2.5 bar and below -0.8 bar negative pressure was successfully tested.

According to a further particular advantageous embodiment of the invention, the connection of the hose can be made by attaching the hose to the outer contour of the hard part. Alternatively, the hose by plugging of the hose into the inner contour of the hard part.

Advantageous the hose is over on the outside or inner contour provided discontinuity areas in the form of projections or Recesses pulled. These discontinuities serve to improve the mechanical stability the overall connection. Since the hot glue inner layer with the Material of the hard part, for example, the polypropylene a relative bad connection is on the Hartteil the appropriate Discontinuity, for example in the form of an undercut, intended. Through the shrunken cuff is now the cuff and as far as the hose over the hard part is pulled, even the hose through a corresponding Positive locking additionally secured.

Furthermore leads the Cuff that in the area of the hard part better protection against kinking is reached.

Advantageous the hard part can have an outer contour with an at least partially circumferential projection, preferably with undercut, have over which pulled the hose is, wherein the shrunk-on sleeve a positive connection manufactures.

alternative the hard part can have an outer contour with at least one at least partially circumferential Have recess over the hose is pulled, with the shrunken cuff a form-fitting Makes connection.

Of the Hose can be advantageously made of polyvinyl chloride and the hard part made of polypropylene.

Advantageous are the projection or the recess of the outer or inner contour of the hard part crowned concave or convex convex executed. As a result, any mechanical stress, the hard-edged transitions, air pockets or Congestion accumulating during of shrinking can occur avoided. By these convex concave or convex discontinuities is a comparatively flat angle between hose and hard part generated, where by detachment of the Hose is counteracted by the hard part under load.

Further Details and advantages of the invention will become apparent from a in the drawing illustrated embodiment. Show it:

1 to 7 : Longitudinal sections through different embodiments of a connection between a hose and a hard part.

In 1 is an example of a compound of a hard part 10 with a hose 12 shown. In the embodiment shown here is the hard part 10 made of polypropylene, while the hose 12 made of PVC. The hard part 10 has a connector approach 14 in which the polypropylene tube 12 , as in 1 shown, is inserted. For connecting the polypropylene hose to the hard part 10 is a shrinking cuff during heat treatment 16 applied, as in the 1 shown, both the extension piece 14 of the hard part 10 , as well as the PVC hose 12 covered. The shrinking during heat treatment cuff 16 has an inner coating of a hot melt adhesive, which the space between fitting 14 of the hard part 10 with the cuff on the one hand and the hose 12 with the cuff 16 on the other hand seals. To allow a better connection between sleeve and hard part, here is provided on the circumference discontinuity point in the form of an undercut 18 on the outer circumference of the neck 14 on the hard part 10 available. The corresponding shrinkage of the sleeve by heat treatment results here as in 1 shown, a positive connection.

2 shows an alternative embodiment of the compound according to the invention, in which case the hose 12 on the approach 14 of the hard part 10 is plugged. As shown here, the tube follows the discontinuity 18 at the Außenkontor of the approach 14 of the hard part 10 , Through the shrunken cuff 16 Here is a positive connection between the hose and the hard part 10 created. For sealing is not shown in detail here, the hot-adhesive layer between the shrunk-on sleeve 16 and the hose 12 ,

3 shows one of the 1 Similar configuration, here consciously a sharp-edged transition of an undercut at the point of discontinuity on the outer circumference of the neck 14 is avoided.

4 shows a still further flattened point of discontinuity 18 with a very shallow angle between the cuff 16 and the hard part 10 ,

In 5 instead of a convex surface increase on the outer circumference, a concave depression on the outer circumference of the hard part 10 except that with here 19 is designated. The shrunken cuff 16 also applies here to the outer contour of the hard part 10 on, so that also here a positive connection is achieved.

The 6 shows one of the 2 Similar variant, where also the point of discontinuity 18 in contrast to the embodiment according to 2 crowned concave. By this training any mechanical stresses are largely excluded, so that the adhesive inner layer can maintain the sealing property with appropriate mechanical stress of the hose.

The 7 largely corresponds to the embodiment according to 6 , here in the area of the hard part a paragraph 15 in the area of the approach 14 of the hard part 10 is formed. As a result, the shrinking during heat treatment cuff 16 steadily between the approach 14 over the attached hose 12 extend, resulting in the 6 resulting sales of the sleeve 16 can be avoided with the appropriate shrinking at the end of the plugged hose.

The in the 1 to 7 illustrated variants of the change in cross section in the region of the hard part 10 are just examples. There are even more variations, especially in the area of the inner surface of the hard part conceivable. However, it should be noted in the embodiment that as far as possible no sharp-edged transitions are created to air pockets and adhesive accumulation during shrinking of the cuff 16 to avoid. Furthermore, a flat angle between hose and hard part should be chosen to prevent detachment under load. Since the adhesive inner layer mainly takes over the sealing function, the shrink-on sleeve must have a sufficiently large adhesive surface both on the hose, as well as on the hard part, so that the tightness is ensured even under stress. A degree of freedom as possible embodiment of the hard-part connector is to be selected so that accidental damage to the sealing adhesive inner layer can be excluded.

Claims (10)

Method for firmly connecting a hose with a hard part, such as a connector or a Port, with the following steps: - Connecting the hose with the hard part and - shrinking a shrinking during heat treatment Cuff in the connection area of hose and hard part. Method according to claim 1, characterized in that that the palm the shrinking cuff is coated with adhesive, so that when Shrinking the cuff results in an adhesive bond. Method according to claim 1 or 2, characterized that this Connect the hose by attaching the hose to the hose outer contour of the hard part takes place. Method according to claim 1 or 2, characterized that this Connect the hose by inserting the hose into the hose Inner contour of the hard part takes place. Method according to one of the preceding claims, characterized characterized in that Hose over on the outside or inner contour provided discontinuity areas in the form of protrusions, preferably Undercut areas, or recesses is pulled. Connection according to one Method according to one of the preceding claims, characterized that about the Hartteil a hose is pulled and that a shrunk Cuff a form-fitting Makes connection. Connection according to Claim 6, characterized that this Hard part an outer contour with an at least partially circumferential projection, preferably with undercut. Connection according to one Method according to one of the preceding claims, characterized that this Hard part an outer contour with at least one at least partially circumferential Well, over the hose is pulled and that the shrunken cuff a form-fitting Makes connection. A compound according to any one of the preceding claims, characterized characterized in that Hose made of polyvinyl chloride (PVC) and the hard part made of polypropylene (PP) exist. A compound according to any one of the preceding claims, characterized characterized in that Projection or the depression of outer or inner contour crowned are concave or convex convex.