Liquid degassing device

The invention relates to a device for removing gases from liquids, in particular a dialysis liquid, according to the preamble of Claim 1.

Such a device is known for example from US-A-4,368,118.

In the construction of an extracorporeal blood circuit as well as in the preparation of Dialysis fluids for dialysis, a plurality of means for Separation of air in the form of bubble traps or air extraction systems known which have the task of the present in the liquid, partially dissolved gases from the fluid effectively to separate.

The coming in dialysis for use dialysis fluids put in Vacuum off gases, said air separator to be used, an upper having inlet which is usually arranged laterally of the incoming and Liquid to impart a spiral path. Here are the bubbles an overhead hydrophobic filters are deposited. such Arrangement is known for example from DE 32 15 003. was in practice but found that the separated air partially in by the resulting suction the outlet is entrained, so that other arrangements had to be made, to enhance the deposition. For example, separating aids were in the form small plates introduced into the hood space. Furthermore, were the Air separator often built very long to the deposition surface as large as possible shape.

From US-A-4,061,031 a device is known, as well as a flow meter can also be used as air separators use. The known device has a container, which is divided by a partition into two chambers, where the one chamber with the inlet port and the other chamber with the Outlet port is provided. The partition wall has an opening and extending from the bottom of the container to close the container ceiling under Forming a gap-shaped space between the inlet chamber and the discharge chamber and the container ceiling.

The perforated partition is offset by two spaced to each other, plate-like elements formed, the openings of the inlet and Outlet chambers are located at the bottom of the container. Since the breakthrough a smaller cross-section than the inlet opening, form in the Chambers liquid columns of different heights from, which makes it possible is to measure the flow. Here, the difference between the two Flüßigkeitsäulen a measure of the amount of mass flow.

In the known device both chambers serve as a bubble trap. The in Liquid in air bubbles rising in the chambers upwards and remain as a gas above the liquid level. An active deposition is at of the known device is not possible. So that the liquid does not have the upper edge of the partition flows into the discharge chamber, has the Inlet chamber has an elongated shape, resulting in a relatively large Height leads.

The US 4,368,118 A describes a device for removing gases from Liquids with a container which by a partition wall into two chambers is divided. The two chambers are beneath the container ceiling over a slit-shaped gap in communication. While the liquid flows from the one via the clearance in the other chamber, are deposited gas bubbles that collect on the vessel top. These gas bubbles then can a provided on the vessel top valve assembly be drained.

The US 4,344,777 describes a similar apparatus for removing gases from liquids. In this device the gas bubbles accumulate it drained below the vessel top, from where a valve assembly can be.

The invention is based on the object, a device for removing to provide gases from liquids, with himself and with a compact design simple construction can obtain a high deposition rate.

The problem is solved according to the invention having the characteristics of Claim 1.

Advantageous developments of the invention are Subject of the dependent claims.

In the apparatus according to the invention, the partition wall as a continuous is Body formed so that the first opening and the second opening only through the slit-shaped gap in flow communication. Further, at the container cover a vent opening provided by a Venting unit is closed, although the gas but no liquid passes. During operation, the container, ie the two chambers and the gap-shaped intermediate space, completely filled with liquid. The liquid to be degassed flows from the a chamber through the gap-shaped space beneath the container ceiling in the other chamber. At the dividing wall can be a reversal of the flow direction instead of, the gases contained in the liquid by the at may leak container ceiling provided vent.

In the apparatus according to the invention the vent is of a closed hydrophobic membrane, so that the liquid to be degassed against the membrane is pressed. The hydrophobic membrane for the liquid should form the largest possible contact surface and preferably virtually over the total cross-sectional area of ​​the gap-shaped intermediate space extending.

A particularly high deposition rate with compact design of the device is in particular achieved when the partition wall in the form of a hollow body is formed within the forming of the first and second chamber the container is arranged such that the inner first chamber a having lower Querschitt than the second chamber exterior. At this Assembly forms the first chamber, the feed chamber and the second chamber forms the discharge chamber. Since the feed chamber has a smaller cross section than has the discharge chamber, the flow velocity in the first chamber and therefore the static pressure is increased to the vent opening. on the other hand the dynamic pressure at the vent hole is made small, so that practically in spite of the increased flow rate in the first chamber no air is entrained.

The supply opening to the first chamber is in a preferred Embodiment designed so that the liquid supplied to horizontal can flow, said horizontal flow component advantageously a tangential Stömungskomponente is impressed. This has the result that the liquid flowing substantially helically is transported upwards, which also the air separation is improved. The incoming fluid mixture is therefore in a rotational movement within the air separator according to the invention offset, whereby gas forcibly towards the common axis is promoted.

In a further preferred embodiment, the bottom of the tubular is The inner part of the first chamber opposite the bottom of the outer part of the second extended chamber down and protrudes accordingly downwardly. At this Embodiment, the inlet opening is adjacent to the tubular side wall to arranged at the bottom, with the with the first opening in flow connection standing supply connector advantageously tangentially to the pipe wall first in the Opening opens.

Similarly, the outlet connection from the second opening may also be arranged horizontally adjacent to the floor and possibly tangentially open to the container wall in the second opening.

Particularly preferred is the embodiment in which the horizontal walls of the first chamber and the second chamber are formed annular and thus forming a tube-in-tube assembly, so that between the first chamber and the second chamber, a circular annular space is formed.

In the following an embodiment of the invention with reference to the drawings erlaäutert closer.

Show it:<dl tsize="6"><dt>Fig. 1</dt><dd>a longitudinal section through a first embodiment of the invention, and</dd><dt>FIG. 2</dt><dd>a view of the embodiment of Figure 1 from below.</dd></dl>

In Fig. 1 with 10 is a device for removing gases from medical Liquids, in particular for removing air from a dialysis fluid shown, comprising a container 12th This container 12 has an in substantially vertically disposed container wall 14 shown in FIG. 1 according to the Embodiment is executed substantially circular. The container 12 is on its underside by a container base 16 and on its upper side by a Vessel top 18 limited.

According to the embodiment shown in Fig. 1 of the container bottom 16 is under Forming a step 20 discontinued, whereby the outer container base in a annular portion 22 and an inner substantially circular area 24 is divided. Accordingly, the stepped portion 20 forms a substantially cylindrical portion 26th

The container 12 has an interior 28 which annularly closed by a Wall 30 into a first chamber 32, the inside of the annular wall 30 is located and a second chamber 34 is divided, a substantially annular having structure, the annular wall 30 and surrounds the container wall 14 is bounded.

The annular wall 30 is secured on the container bottom 16 and according to the in Fig. 1 embodiment is formed so that it on the annular Bottom portion 22 merges into the cylindrical region 26 and with this area coincides. On the other hand, but also the entire floor 16 just be formed so that the annular wall 30 is positioned on this bottom and with This floor is fixed.

In the area of ​​the bottom 16 is a first opening in the first chamber 32 38 provided that is advantageously used as a supply port. This first Opening 38 is according to the embodiment shown in Fig. 1 in the down protruding cylindrical portion 26 arranged.

The bottom 16 of the opposite end of the annular wall 30 is in the proximity the vessel top out 18 and there opens into a tubular opening 39 by a circumferential edge of the tube 40 is limited which an overflow weir for a supplied Liquid represents. is between the edge of the tube 40 and the vessel lid 18 gap-shaped flow space 42 is provided between a flow connection the first chamber 32 and second chamber 34 via the tube edge 40 away creates.

The cross-sectional shape of the container 12 as well as its members 14 and 30 is substantially not critical, but preferably circular, and the two Pitch circles of the outer wall 14 and the wall 30 is preferably a common have circle center.

Advantageously, the inner first chamber 32 as influent designed during the concentric outer second chamber 34 as Drainage chamber serves. Here, the discharge chamber is advantageously greater Cross-section than the feed chamber, so that the liquid over the edge of the tube 40 away can flow substantially unimpeded. prevails in the whole container no significant pressure differential.

It should be added, however, that a different flow to the container is possible, for example, a flow from the outside to the inside, although this is not preferred is.

According to the embodiment of Figs. 1 and 2 is connected to the first chamber 32 in the region the first tube opening 38, a first pipe socket 44 arranged. It opens the Tube longitudinal axis of the pipe socket. 44 - as shown in Figure 2 can be seen - advantageously tangentially into the circular shape of the first chamber 32 and extends in the other Position of use substantially horizontal.

Further, at the second chamber 34 a in the area of ​​the second opening 36 the second pipe connection 46 is disposed which serves as a drain connecting piece, whereby its axis is advantageously also arranged horizontally in the use position.

The arrows shown to the pipe sockets 44 and 46 in Fig. 1 or 3 are thereby the respective inlet and outlet directions.

Furthermore, the container cover 18 has a vent opening 48 that with a venting unit is closed. In the shown in Fig. 1 Embodiment, the ventilation unit is a microporous hydrophobic filter 50, which does not, however, the aqueous liquid passes the separated gas. As far as the hydrophobic filter is concerned, to the disclosure of DE 32 Reference 15 003 taken.

The container 12 is typically made of a plastic material and is used for the separation of air in the production of, for example dialysis fluid as Primärluftabscheider. Here, from the freshly prepared liquid first the physically dissolved in a vacuum path in the liquid Air released. The liquid / air mixture is the pipe stub 44 fed, due to the tangential introduction, the mixture helically moved upward and thus the air in the direction of body axis forcibly separated to form small bubbles from the fluid becomes.

takes place in the area of ​​the hydrophobic membrane 50 and the charge pressure valve 56 Then, the separation of air.

A great advantage of the inventive apparatus for removing gases is the simple continuous, highly efficient air separation, particularly in the single-pass dialysis. A further advantage is that the container of the Device is constantly filled with liquid, so that in this way a very good Disinfectant or Freispülbarkeit is given. Finally, the dimensions of the A device according to the invention because of their good release properties against the aerators should be reduced by about half currently employed.