JPS61143073A - Disposable filter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disposable filter suitable as a blood filtration device for sterile gas exchange in a closed container and hose system, consisting of a plurality of disposable filters made of plastic and rigidly connected to each other. A selectively permeable hydrophobic flat filter strip is clamped fluid-tightly between the two casing parts on the edge side;
It separates a large lower collection chamber for the fluids to be degassed (liquids and gases) and a smaller upper collection chamber for gas exchange with a drainable filter support.
It concerns a type in which both collection chambers lie in a circular connection located in the center of the casing part.

For sterile air supply to containers and hose systems, small-volume disposable filters are usually used (DE 32 02 430).

For hemodialyzers and hemofilters used as artificial bones, Extracorporal (
Upstream of the pressure manometer for measuring the blood pressure occurring in the extracorporal system, there is a blood filtration device (Blutspi) in the form of a filter of the type mentioned at the outset.
epelsperre) is fitted. The hydrophobic filter diaphragm attempts to prevent blood or blood bubbles from entering and fouling the interior of the manometer and from blood flowing out of the hose system. The operator must notice and take action regarding blood bubbles or rising blood. This is done by removing the connection on the manometer side of the blood filter and using a syringe to push the blood plane down from the underside of the diaphragm. In this case too, it must be ensured for safety reasons that blood does not penetrate the diaphragm and expose the operator to the risk of hepatitis. BACKGROUND OF THE INVENTION Conventionally, blood filtration devices have a circular filter cross section, ie the casing parts are designed rotationally symmetrically. A large funnel-shaped chamber located upstream of the hydrophobic diaphragm additionally allows blood bubbles to melt during generation. In known filters, the housing chamber for the blood is designed to be small;
As a result, no air bubbles are removed.

However, an excessively large casing chamber is not desired. This is because it is desired that as little blood as possible remains in the conduit system and that as little blood as possible remains in the conduit system at the end of the procedure.

Known filter housings with a rotationally symmetrical design are often removed from the hose system and are extremely difficult to grasp during treatment. Furthermore, cutting the flat filter into circular shapes in order to obtain an effective predetermined filter surface results in a relatively large amount of waste, and cutting errors increase manufacturing costs. Therefore, it is desirable to have a disposable filter that is as small and inexpensive as possible, but at the same time has as large an effective filter surface as possible, and that is easy to grasp during treatment.

It is therefore an object of the present invention to make the above-mentioned disposable filter easy to handle by simple means, to form a casing volume of optimum dimensions that allows the removal of blood bubbles, and to increase the filter efficiency, but also to reduce the filter efficiency. The purpose is to avoid increasing the filter cutting surface required for cutting and the filter surface that is cut incorrectly.

In order to solve this problem, the present invention provides that the flat filter section has a rectangular contour and that tension bearings for the flat filter section are suitable at the edges of both casing parts. in such a way that the exposed filter surface facing the lower casing chamber is limited by the approximately rectangular casing wall of the lower casing part, which flows into the hemispherical casing wall. transition and connect to the lower connection, the diameter of the hemisphere of the hemispherical casing wall approximately corresponds to the diameter of the circle drawn in the cuboid, and the transition of the inner casing cross section is rounded. It is attached.

Advantageous embodiments of the invention are described in the subclaims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The filter casing shown in FIGS. 1 to 6 is of two-part construction, ie the casing consists of an upper casing part 1 and a lower casing part 5. The filter casing shown in FIGS. The upper housing part and the lower housing part have a central connection 2.6.

The upper part 1 of the casing has an integrated filter support 3 consisting of intersecting ribs. The housing edges facing each other are configured with an edge length of, for example, 22 plates, in order to receive square flat filter strips 4, the receiving bearings 8 of the upper housing part and the lower housing part being sensitive flat. Filter fragment (diaphragm) 4
In order to avoid load peaks occurring at zero corners, the clamping is curved (rounded) at the corners and has a section 8a. Although the filter is rounded at the corners, the use of square filters is significantly advantageous over circular filters, which are generally formed by stamping with circular cutting tools. Especially PTFF2 (Polytetraf'
Square cutting is economical for relatively expensive filter materials made from polytetrafluoroethylene. The lower part 5 of the casing has a step 7 on the inside from the rectangular profile, which is for a separate selectively attachable frame 10 with a filter lower support groove 9 (FIG. 4). It is configured as a receiving bearing part.

A rectangular hollow casing section 5a adjoining the step of the lower casing part flows into a hemispherical hollow casing section 5a;
b continues to the central connecting portion 6 having a circular cross section. As a result, a transparent collection chamber 12 shaped like a calyx is formed in the lower part of the casing, as is clear from FIG. The volume of the collection chamber 11 in the upper part 1 of the casing is significantly smaller. In the large collection chamber 12 foamable liquids, for example blood bubbles, can be dissolved before they reach the flat filter strips 4. The flat filter strips 4 prevent the passage of blood or blood bubbles in the direction of the connection 2. A pressure manometer (not shown) is arranged downstream of the connection 2.

The upper housing part and the lower housing part are made of plastic and are joined at the edges, for example by ultrasonic welding. The filter supports provided on both sides in the embodiment of FIG. 4 allow pressure loading from both sides of the filter element.

This is desirable for certain fields of use.

The rectangular structure of the casing flanges that are connected to one another makes it easier to grip the filter casing and facilitates handling of the filter casing when removing it from the hose connection on one or both sides.

The connection 2.6 may be constructed as a screw connection customary in pharmaceuticals.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view of the first embodiment, and FIG. 2 is a cross section taken along line 2-2 in FIG. 6. Figure 6 is a bottom view of the casing of the first embodiment;
The figure is a sectional view of the second embodiment, and FIG. 5 is a plan view of the filter support part of the second embodiment. 1... Upper part of the casing, 2... Connection part, 3...
・Filter support part, 4... Flat filter piece, 5.
...Casing lower part, 6... Connection part, 7... Step part, 8... Receiving support part, 8a... Tightening is classified, 9...
... Filter lower support part, 10 ... Frame, 11 and 12 ... Collection chamber

Claims (1)

[Claims] 1. A disposable filter suitable as a blood filtration device for sterile gas exchange in a closed container and hose system, 2. made of plastic and rigidly connected to each other.
Between the two casing parts, a selectively permeable hydrophobic flat filter strip is clamped liquid-tight on the edge side and provides a large catchment area on the underside for the fluids to be degassed (liquids and gases). Separates the collection chamber from a small upper collection chamber for gas exchange with a drainable filter support, with both collection chambers transitioning into a circular connection located in the center of the casing part In this version, the flat filter strip (4) has a rectangular contour and the edges of both casing parts (1, 5) are provided with a flat filter strip (4).
A tensioning bearing (8) for the is suitably constructed such that the exposed filter surface facing the lower housing chamber (12) is connected to the approximately rectangular housing wall (5) of the lower housing part (5). 5a), which casing wall transitions fluidly into a hemispherical casing wall (5b) and terminates in a lower connection (6), the diameter of the hemisphere drawn into the cuboid. Disposable filter, which corresponds approximately to the diameter of the circle in which the filter is inserted, and is characterized in that the transition part of the inner casing cross section is rounded. 2. The lower casing part (5) is directly attached to the tension bearing part (
8) has an annular stepped portion (7) that limits the size of the exposed filter surface, and the stepped portion is surrounded by a frame shape and covers the lower surface of the flat filter cut piece (4). 2. Disposable filter according to claim 1, which is configured as a receiving bearing for a supporting plastic support grid (9, 10). 3. The disposable filter according to claim 1 or 2, wherein the flat filter cut piece (4) is constituted by a microporous diaphragm made of PTFE.