Closure cap for dialyzers

The invention relates to a closure cap (1) for dialyzers which is suitable for a so-called in-line sterilization. For this purpose the closure cap (1) comprises two cap parts (2, 3) of which the first cap part (2) is adapted to be mounted on a dialyzer flange (4) while the second cap part (3) is arranged movably in a receiving compartment (5) of the first cap part (2) between an open position and a closure position. In an open position passage of a sterilization medium is possible so that all the parts, sealing and guide surfaces can be reliably sterilized. In the closure position the second cap part (3) is pushed into a sealing position within the first cap part (2) so that contamination of the dialyzer after removal from the sterilization apparatus can be prevented with certainty.

DESCRIPTION 
The invention relates to a closure cap for dialyzers according to the 
preamble of claim 1 and a dialyzer provided with such a closure cap. 
After their actual manufacture dialyzers must be sterilized before they are 
stored. In devising the sterilization method as so-called in-line method 
any open contact with the external air after carrying out the 
sterilization step must be avoided. For this reason, the dialyzer must be 
sealed in germ-tight manner before it is removed from the sterilization 
bench. 
A closure cap corresponding to the preamble of claim 1 comprises a first 
cap part which is introduced with two legs into an annular recess of a 
dialyzer flange and to which a second cap part is secured which is movable 
between an open and a closure position. Said second cap part comprises a 
closure plate which is connected via an articulate connection to the first 
cap part and on which a guide member is provided which in the closure 
position engages into a connecting flange of the first cap part. 
It has however been found that the closure cap according to the preamble is 
not germ-tight enough. 
Furthermore, the known closure cap does not make it possible during the 
sterilization to sterilize the flange inner surfaces by the sterilizing 
agent as well. Finally, the closure cap according to the preamble is 
disadvantageous in so far as it is not suitable for use in in-line 
sterilization methods for dialyzers. 
The problem underlying the present invention is therefore to provide a 
closure cap for dialyzers according to the preamble of claim 1 which is 
suitable for use in in-line sterilization methods for dialyzers, which 
permits a germ-tight closure both on the blood side and on the dialyzate 
side and which moreover permits the simultaneous sterilization of the 
flange inner surfaces in the course of the sterilization. 
This problem is solved by the features of claim 1. 
The closure cap according to the invention permits a germ-tight sterile 
closure when the closure cap is fitted and in the closure position which 
permits insertion of the externally unsterile dialyzers into an unsterile 
surrounding packing. In a first embodiment a covering is effected in which 
the outer sleeve engages over the dialyzer flow in sterile manner 
externally whilst in a second embodiment the sterile seal is via an 
elastic sealing means. 
Due to the design-inherent connection facility to an in-line sterilization 
apparatus it is possible to avoid LF-protected aseptic closure stations. 
Furthermore, the sterilization of the flange inner sides of the dialyzer 
increases the microbiological safety. 
The in-line sterilizable closure cap according to the present invention is 
advantageously suitable for preassembly in the opened state and remains on 
the dialyzer during and after the sterilization. All the cap inner sides 
are also sterilized and it is possible to automatically seal the closure 
cap before removal of the dialyzer from the production process so that a 
germ-tight seal is ensured both on the blood side and on the dialyzate 
side. 
This avoids any open contact with the outer air after carrying out the 
sterilization so that the dialyzer is sealed from the outside in 
germ-proof manner; in addition to automatic locking, manual locking is 
also possible. 
By using the closure cap according to the invention, to avoid transmission 
of contaminations it is possible to keep completely germ-free a connection 
means provided on the dialyzer flange, for example in the form of a screw 
connection. 
Due to the design of the closure cap according to the invention it is 
advantageously possible to sterilize all the sliding surfaces and the 
contact region to the dialyzer flange, the sterilization of the connector 
extension on the flange also being possible. 
A further advantage to be emphasized of the closure cap according to the 
invention is that it is suitable for all types of sterilization methods 
with all sterilization agents usual at present, such as hot and cold 
sterilization media. Furthermore, the closure cap according to the 
invention can be used both in dialyzers which are dried after the 
sterilization and in dialyzers which are filled for example with brine 
solution. 
Moreover, the closure cap according to the invention can be used both on 
the blood side of the dialyzer and on the dialyzate side thereof. 
The subsidiary claims contain advantageous further developments of the 
invention. In particular, it is possible to design the arresting means as 
intactness fastener or sealing means which can be provided with exactly 
defined desired breakage points. 
All in all, the construction of the closure cap according to the invention 
makes it possible to carry out in-line sterilization methods with liquid 
and gaseous/vapour media and the dialyzers can be delivered both filled 
with solution and dry.

In FIGS. 1 to 3 a closure cap 1 according to the invention for the blood 
side of dialyzers is illustrated. 
The closure cap 1 comprises a first cap part 2 a second stopper-like cap 
part 3. 
The first cap part 2 is made substantially tubular, a preferred embodiment 
being cylindrical. Furthermore, the first cap part comprises a first 
portion 6 and a second portion 16. In the first portion 6, the outer 
dimension of which is less than that of the second portion 16, a receiving 
compartment 5 for the second cap part 3 is arranged. Furthermore, the 
first portion 6 forms a rearward portion of the first cap part 2 which 
forms the connection point to an in-line sterilization apparatus and for 
this purpose can be provided if necessary with suitable connection means. 
The receiving compartment 5 comprises three consecutive subchambers 7, 8, 
9. Said subchambers 7, 8, 9 are arranged from an open end side 10 with 
decreasing diameters towards an end region 11 of the first portion 6 
opposite the end side 10 in said portion 6. Between the first subchamber 
7, which adjoins the end side 10 and has the largest diameter or the 
largest internal dimension, and the second subchamber 8 a step 12 is 
arranged which extends inwardly substantially perpendicularly to the 
longitudinal axis of the first cap part 2. 
The second subchamber 8 and the third subchamber 9, which has the smallest 
internal diameter and the smallest internal dimension, are connected 
together via a frustoconical intermediate portion 13 whose inner surface 
provides a gradual transition from the inner surface of the second 
subchamber 8 to the inner surface 15 of the third subchamber 9. 
The inner surface 14 of the first subchamber 7 is made smooth and serves as 
guide and retaining surface for the second cap part 3 which will be 
described in detail hereinafter. The inner surface 15 of the third 
subchamber 9 likewise forms a guide surface for a corresponding surface of 
the cap part 3, as will also be explained in detail hereinafter. 
The second portion 16 of the first cap part 2 is connected to the first 
portion 6, the second portion 16 adjoining an end region 11 of the first 
portion 6 via a frustoconical connecting surface. The second portion 16 is 
open at its end side 17 opposite the end face 10, the end side 17 being 
adjoined inwardly by three subspaces 18, 19 and 20. The subspace 18 
directly adjoining the end side 17 has a greater internal diameter or a 
greater clear width than the middle subspace 19. The subspaces 18 and 19 
are connected together via a step 21 which extends inwardly substantially 
perpendicularly to the longitudinal axis of the first cap part 2. 
As apparent from FIG. 2 the inner surface 22 of the second subspace 19 
forms a guide and sealing surface for a dialyzer flange 4. The inner 
surface 22 of the second subspace 19 lies on the correspondingly outwardly 
directed wall region 4' of an outer encircling connector extension. As a 
result, the inner space defined by the dialyzer flange 4 and the subspaces 
18 to 20 is sealed. 
The third subspace 20 of the second portion 16 comprises a frustoconical 
inner surface 23 which provides a gradual transition between the second 
subspace 19 and the third subspace 9 of the first portion 6. As apparent 
from FIG. 1, this arrangement provides a flow connection which extends 
through the entire inner space of the first cap part 2 from the one end 
side 10 to the other end side 17. 
As further apparent from FIG. 1, within the subspaces 18 to 20 
concentrically to the second portion 16 a pot-shaped insert member 24 is 
fixed, for example by radially outwardly directed struts. The outer 
surface 25 of the insert member 24 defines a free flow passage with the 
inner surfaces of the subspaces 18 to 20. 
In particular, the insert member 24 comprises an open end side 26 which 
preferably lies in a plane with the open end side 17 of the second portion 
16. It is however conceivable for the end sides 26 and 17 to be arranged 
in different planes. 
The insert member 24 further comprises a preferably cylindrical boundary 
wall 27 which extends concentrically round the longitudinal axis of the 
first cap part 2. At the side opposite the open end side 26 said boundary 
wall 27 is preferably integrally connected to a closure or termination 
wall 28 which extends perpendicularly to the longitudinal axis of the 
first cap part 2. The closure wall 28 comprises on its side facing the 
subchamber 9 an outer surface 29 which is likewise preferably arranged 
perpendicularly to the longitudinal axis of the cap part 2. 
As further apparent from FIG. 1, in the wall of the second portion 16 a 
recess 45 is disposed which passes through the wall. Said recess or cutout 
45 serves to fix the second cap part 2 on the dialyzer flange 4 which for 
this purpose comprises a detent projection 46 which in the embodiment 
illustrated projects radially outwardly. The detent position can be seen 
in detail in FIGS. 2 and 3. To assume this detent position the 
corresponding portions of the dialyzer flange 4 and of the second cap part 
2 are made elastically yielding and provided with corresponding runup 
ramps which can be seen in detail in the illustration of FIG. 1. Instead 
of such a snap-action detent connection it is also possible to provide a 
threaded connection, a bayonet fastener or similar locking means. 
Also shown in detail in FIG. 1 is the form of the second cap part 3. The 
second cap part 3 is made pot-shaped and for this purpose comprises a wall 
30 which extends round the longitudinal axis and defines an inner space 
31. The wall 30 is preferably made cylindrical. The inner space 31 is open 
at an end face 32 and the rear portion 30' of the wall there can if 
necessary form the connecting portion for the in-line sterilization 
apparatus. Said portion can be provided with suitable connection means. At 
the opposite end side the inner space 31 is closed by a closure wall 33 
arranged substantially perpendicularly to the longitudinal axis. 
In the case of the example the wall 30 comprises two connecting openings 34 
and 35 which extend from the inner space 31 up to the outer wall surface 
36 of the wall 30 so that they create a flow formation from the outer 
region of the second cap part 3 to its inner space 31. 
Furthermore, FIG. 1 shows the arrangement of a guide and retaining means 37 
on the outer wall surface 36 of the wall 30. In the case of the example 
the guide and retaining means 37 comprises a guide ring 38 which extends 
concentrically at a certain spacing round the outer wall surface 36. The 
guide ring 38 is provided at its end facing the end side 32 with a stop 
ring 39 which extends radially outwardly from the guide ring 38 and thus 
forms an outwardly projecting edge. At its other end the guide ring 38 is 
connected via a collar 40, arranged inclined with respect to the 
longitudinal axis, to the wall 30. Preferably, this arrangement is an 
integral connection. 
The closure cap 1 described above is shown in FIG. 2 in its open position. 
In this position the second cap part 3 has been inserted into the 
receiving compartment 5 of the first cap part 2. As shown in FIG. 2, in 
this position the outer surface of the guide ring 38 bears on the inner 
surface 14 of the first subchamber 7. Furthermore, the stop ring 39 of the 
guide ring 38 bears on the end face of the end side 10 of the first cap 
part 2 and thus limits the axial position of the second cap part 3 within 
the receiving compartment 5 of the first cap part 2. In the position shown 
in FIG. 2 the first cap part 2 is connected to the dialyzer flange 4 in 
the manner described above, the sealing surfaces 4' and 22 sealing the 
space formed between the dialyzer flange and the second portion 16 of the 
first cap part 2. 
As FIG. 2 further illustrates, by the axially limited position of the 
second cap part 3 within the receiving compartment 5 a free passage of the 
sterilization medium through the entire arrangement is ensured. 
Consequently, it is possible in the sterilization to completely sterilize 
all the parts and sliding surfaces of the arrangement shown in FIG. 2 and 
thus render them completely free from germs. This makes it possible to use 
the closure cap according to the invention in a so-called in-line 
sterilization, which means that the sterilization takes place in the 
production line of the dialyzer. 
After completion of the sterilization the second cap part 3 is moved, 
preferably automatically, into its closure position shown in FIG. 3. For 
this purpose the second cap part 3 is pressed along the longitudinal axis 
in the direction towards the insert member 24. FIG. 3 shows that in this 
movement the elastically resilient guide ring 38 deforms towards the wall 
30 so that insertion of the second cap part 3 into the receiving 
compartment 5 is possible. The insertion is continued until the outer 
surface of the closure wall 33 of the second cap part 3 comes into sealing 
engagement with the outer surface 29 of the insert member 24. The inner 
surface 15 of the third subchamber 9 here takes on a guiding and sealing 
function. The closure or sealing position of the second cap part 3 within 
the first cap part 2 illustrated in FIG. 3 is secured by the engagement of 
the stop ring 39 on the inner surface 14 because the guide ring 38 due to 
its elastically resilient construction presses the stop ring 39 against 
the inner surface 14. It is possible to design the aforementioned parts in 
such a manner that the second cap part 3 forming a plug can no longer be 
moved into its open position. In this position the dialyzer, which due to 
the closure cap 1 is sealed germ-free, can be removed from the 
sterilization apparatus and by the arresting means constructed as bayonet, 
snap-action or screw connection, a detaching of the closure cap 1 from the 
sterilizer, for example in the unsterile packaging, is reliably prevented. 
As already mentioned, the closure cap 1 illustrated in FIGS. 1 to 3 is the 
embodiment for the blood side of the dialyzer. 
On the other hand, in FIGS. 4 to 6 the embodiment of the closure cap 1 
according to the invention for the dialyzate side is shown. As apparent 
from FIGS. 4 to 6 the closure cap for the dialyzate side is constructed in 
its essential parts exactly like the closure cap 1 for the blood side. In 
this respect reference can therefore be made to the explanations on FIGS. 
1 to 3. 
As difference for adaptation to the dialyzate side of the dialyzer it is 
first to be pointed out that the third subspace 20 of the second portion 
16 forms a transition between the second subspace 19 and the fourth 
subspace 41 which via a central connecting recess 42 is connected to the 
third subchamber 9 of the first portion 6. The connecting recess 42 is 
defined by an encircling stop wall 43 projecting inwardly to the 
longitudinal axis. The stop wall 43 comprises a sealing surface 44 which 
is arranged on a side facing the third subchamber 9. 
It is additionally apparent from FIG. 4 that the second subspace 19 is made 
longer in the axial direction than the second subspace 19 of the first cap 
part 2 according to FIGS. 1 to 3. FIGS. 4 to 6 also show that the first 
cap part 2 in this embodiment is connected via a screw connection to the 
corresponding connector piece of the dialyzate side. This is however not 
an essential difference because the snap-action detent connection shown in 
FIGS. 1 to 3 may also be provided. 
FIGS. 5 and 6 again show the open and closure position of the closure cap 
1. These positions correspond essentially likewise to the positions 
according to FIGS. 3 and 4. However, due to the differently constructed 
first cap part 2, which does not have an insert member, the sealing point 
is located between the sealing surface 44 of the stop wall 43 and the 
corresponding adjacent surface region of the closure wall 33 of the second 
cap part 3. This is apparent in detail from the illustration of FIG. 6. 
Otherwise, with the embodiment f the closure cap 1 according to the 
invention for the dialyzate side the same effects and advantages are 
achieved as those of the closure cap construction for the blood side so 
that in this respect as well attention may be drawn to the corresponding 
explanations in connection with FIGS. 1 to 3. 
It should be additionally pointed out regarding the cooperating arresting 
means 45 and 46 on the first cap part 2 and on the dialyzer flange 4 
respectively that the latter may be designed as intactness seal closure. 
It is conceivable for this purpose to provide a tear-off securing means or 
to provide the arresting means 46 constructed as nose on the dialyzer 
flange 4 with an exactly defined desired breakage point. 
Finally, the closure cap 1 can also be made in one piece provided that 
corresponding injection-molding technology precautions are taken. 
Accordingly, the two cap parts 2 and 3 may be connected together via a 
flexible web which allows both an axial pushing together of the two parts 
as well as a radial turning of said two parts to a certain extent. This 
web, not shown, is integrally formed on the two cap parts. 
In accordance with FIG. 7 a second embodiment of a closure cap according to 
the invention is shown, for the blood side of dialyzers, all the parts 
identical with the previous embodiment being provided with the same 
reference numerals. 
Accordingly, the second embodiment of the closure cap 1 also comprises a 
first cap part 2 and a second stopper-like cap part 3. 
The first cap part 2 is again made essentially tubular, cylindrical in a 
particularly preferred embodiment. As FIG. 7 shows the cylindrical 
boundary wall 27 of the cap part 2 of the second embodiment is provided 
with an outer thread 50 which in the assembled state cooperates with an 
inner thread 51 of the only partially illustrated dialyzer flange 4. The 
outer dialyzer flange 4 is accommodated in an elongated receiving 
compartment 53 which is arranged between the outer second cylindrical 
portion 16 and the inner boundary wall 27. 
An inner cylindrical dialyzer collar 53 arranged concentrically with the 
outer dialyzer flange 4 is arranged in a concentrically disposed receiving 
recess 54 of the portion 16 and extends into the region of a cylindrical 
extension 55 which is provided with a passage recess 56 which is in 
communication with the recess 54 of the second portion 16. 
Facing towards the open end side 57 the boundary wall 27 comprises an 
annular encircling groove 59 in which a sealing element, preferably in the 
form of an O ring 60, is inserted. As FIG. 7 shows the O ring in the 
assembled state bears on the dialyzer collar 53 and the boundary walls of 
the groove 59 in such a manner that in the embodiment according to FIG. 7 
at this point a sterile sealing of the dialyzer is effected when the 
closure cap 1 is screwed on. FIG. 7 shows that here on the side of the 
open end side 57 the groove 59 is provided with an encircling inwardly 
directed collar 61 which serves to prevent the O ring 60 slipping out of 
the groove 59 in the unassembled state of the closure cap 1. 
As further shown in FIG. 7 a flow connection is established between a flow 
passage 58, which is arranged within the dialyzer collar or the inner 
dialyzer flange 53, and the passage recesses 56 of the extension 55. The 
passage recess 56 of the extension 55, in the position of the plug-like 
cap part 3 shown in FIG. 7, again communicates with the receiving 
compartment of the first portion 6 of the first cap part 2 because the 
plug-like cap part 3 in the position illustrated in FIG. 7 is arranged at 
the end sides in the receiving chamber 5 so that the closure wall 33 of 
the second cap part 3 is spaced from an annular sealing surface 62 which 
is chamfered in frustoconical manner. A correspondingly formed outer 
sealing surface 63 is arranged on the outer edge of the closure wall 33. 
The cap part 3 is guided within the receiving recess 5 via for example a 
total of four vanes 64 to 67, the arrangement and configuration of which 
can be seen in particular from FIGS. 9 to 11. The vanes or fins 64 to 67 
are made flat and extend from the end side 32 of the cap part 3 
approximately into the centre portion thereof, seen in the longitudinal 
direction. As FIG. 11 shows the vanes 64 to 67 are each spaced by 
90.degree. and arranged round the outer periphery of the cap part 3 and 
have at their radially outer ends on the side of the end side 32 
projections of which the projections 68 and 69 are visible in FIGS. 9 and 
10. At the end side the first portion 6 of the cap part 2 is provided with 
an outwardly widening chamfer 70, the form of which corresponds to the 
projections of the vanes 64 to 67. 
In the control position illustrated in FIG. 7 the projections of the vanes 
64 to 67 lie in said chamfer 70 so that a certain resistance must be 
overcome on pressing the second cap part 3 in the direction towards the 
extension 55. By the radially outwardly extending arrangement of the vanes 
64 to 67 the second cap part 3 is centered in the receiving compartment 5 
and can be pushed from the position illustrated in FIG. 7 into a position 
into the inner space in which sealing surfaces 62 and 63 bear on each 
other, thereby providing a sealing of the through recess 56 so that the 
dialyzer is hermetically sealed. On moving back to the position shown in 
FIG. 7 the flow connection between the passage recess 56 and the receiving 
compartment 5 is reestablished and due to the arrangement of the vanes 64 
to 67 at intervals of 90.degree. on the outer periphery of the cap part 3 
between the vanes and the inner boundary wall 14 a flow cross-section is 
likewise freed. 
With regard to the embodiment of the cap part 2 of the closure cap 1 
according to FIG. 7 it should further be stated that said cap comprises on 
the first and second portions 6 and 16 respectively in each case a 
plurality of outwardly directed reinforcing ribs of which the reinforcing 
ribs 70 to 73 are visible in FIG. 7. The reinforcing ribs 70 and 71 on the 
first portion 6 are drawn radially outwardly to such an extent that they 
correspond approximately to the outer diameter of the second portion 16. 
Between the ribs 70 and 71 a plurality of further ribs with radially 
smaller dimensions may be provided. 
Otherwise, with regard to all identical features of the embodiments 
according to FIGS. 1 to 3 and those according to FIGS. 7 to 11 attention 
is drawn to the above explanations. 
Finally, FIG. 8 shows a cap part 1 for the dialyzate side which in its 
essential features corresponds to the cap part according to the embodiment 
of FIG. 7. Consequently, here as well a sealing is provided by means of an 
elastic sealing device, preferably in the form of an O ring 60, and a 
second cap part 3 is used which corresponds to that of FIGS. 9 to 11. 
Consequently, in this respect reference can be made to the explanations of 
FIGS. 7 and 9 to 11. 
Due to the different configuration of the dialyzate-side flange of the 
dialyzer the cap part 1 on the dialyzate side is formed corresponding to 
the constructional modifications according to the embodiment of FIGS. 4 to 
6 and thus comprises in particular an extended second portion 16 which 
adjoins the first portion and in the region of the end-side opening of 
which an inner thread 74 is arranged for cooperating with an outer thread 
on the dialyzate-side flange of the dialyzer. Furthermore, as difference 
from the cap part according to FIG. 7 it should be emphasized that the O 
ring 60 is arranged nearer the extension 55 but also lies in a groove 59 
so that when the dialyzate-side cap part 1 illustrated in its open 
position in FIG. 8 is screwed on a sterile seal likewise results due to 
the O-ring seal 60. 
With regard to all other common features attention can again be drawn to 
the embodiment according to FIGS. 4 and 6 and to the features in common 
with the cap part 1 according to FIG. 7.