Bag for solid concentrate

Abstract

The invention relates to a bag (1) consisting of soft walls, equipped with an introduction fluid line for introducing dissolved water and an extraction fluid line (121, 122) for extracting the obtained solution. According to the invention, the interior of the pouch has a substantially V-shaped lower edge (13), the tip of the V being farther from the center of the pouch than the branches of the V, the extraction fluid line leading into the pouch at a location closest to the tip of the V.

Description

[0001] This application is a divisional application of the patent application, filed on May 28, 2019, application number 201910449358.5, with the title "Bag for solid concentrate". TECHNICAL FIELD

[0002] The present invention relates to a bag composed of a soft wall, provided with an introduction fluid line for introducing water for dissolution and an extraction fluid line for extracting the solution obtained. BACKGROUND

[0003] Such bags are generally used for the manufacture of hemodialysis solutions, in particular solutions based on solid concentrates, such as alkaline solid concentrates.

[0004] A hemodialysis treatment requires between 120 and 240 liters of dialysis solution. For bicarbonate dialysis, the dialysis solution is produced on-line in a just-in-time manner, based on an acid concentrate and an alkaline concentrate.

[0005] The acid concentrate generally consists of various electrolytes, an acid and glucose. Due to the presence of several components with different dissolution speeds, the acid concentrate is generally provided in the form of a liquid concentrate. If a solid acid concentrate is used, it should be completely dissolved before the treatment, to ensure the correct composition of the liquid concentrate. The container for the solid concentrate should thus have a sufficiently large volume to dissolve the entire contents before the treatment begins.

[0006] This condition of complete dissolution before the treatment is not necessary for the alkaline concentrate. Indeed, the alkaline concentrate generally consists of a single component of sodium bicarbonate. The liquid concentrate is a saturated solution of sodium bicarbonate, which can be produced continuously throughout the duration of the treatment. The bag containing the solid concentrate is connected to a hemodialysis generator, which will introduce water for forming the saturated solution into the bag. When this condition is met, the supply of water and the extraction of the saturated solution are carried out simultaneously until the solid concentrate is completely dissolved.

[0007] For reasons of cost and logistics, the bag should be as small as possible and the amount of bicarbonate should be as small as possible, noting that the amount of bicarbonate should be sufficient to ensure a treatment with a single bag. Indeed, the replacement of the bag during the treatment requires time and a significant amount of manual labor.

[0008] Different bags in the prior art are known which make the dissolution of bicarbonate as efficient as possible. For example, the connector for connecting the bag to the hemodialysis generator can be fixed at a high point of the bag. Water thus flows into the concentrate from the high point, while the extraction tube extracts the concentrate in the bottom of the bag. In order to improve the dissolution of the salt at the end of the process, it is known to incline the lower edge of the bag so that the remaining salt falls into one of the two corners of the bag. The inclined edge has a ramp effect which forces the bicarbonate which has not yet dissolved to accumulate in the bottom of the bag in as small a volume as possible. In addition, the extraction tube can be arranged in a reliable manner in this zone.

[0009] However, the inclination of the bottom of the bag is not the optimal solution because the undissolved salt does not fall in a reproducible manner into the narrow part of the bag. The inclination must also be quite small if it is not desired to increase the size of the bag too much. Some studies have shown that the quantity of undissolved salt remaining in the bag is very variable. In order to have a sufficient quantity in any case to complete the treatment, an overage of about 100 to 200 grams of bicarbonate should be prepared. SUMMARY

[0010] The object of the present invention is thus to modify the bag in the prior art so as to greatly reduce the quantity of solid concentrate which is added in excess in order to ensure that the quantity of liquid concentrate is sufficient to carry out hemodialysis, without having to significantly increase the size of the bag.

[0011] This object is achieved by giving the bag an interior with a lower edge which is substantially V-shaped, the tip of the V being further from the centre of the bag than the branches of the V, the extraction fluid line leading to a position in the bag which is closest to the tip of the V. By choosing two inclined edges, the two branches of the V, instead of one, it is possible to make the inclination of the lower edge sufficient to ensure that the remaining solid concentrate falls under the effect of gravity into the tip of the V which constitutes the lowest point of the bag, while keeping the bag at a regular size.

[0012] Preferably, the connection zone between the two branches of the V is rounded. This avoids the presence of a corner in which the salt which has not been penetrated by the water accumulates.

[0013] The two branches of the V can have the same inclination and / or the connection zone between the two branches of the V can be at the centre of the lower edge. The combination of these two features makes it possible to obtain a symmetrical bag. The branches of the V are preferably obtained by welding on the bag itself.

[0014] In order to follow the deformations of the bag as it is filled and to avoid the creases which result therefrom with mechanical stresses, the lower edge of the bag can be followed by an intermediate zone after each branch of the V, opposite the tip of the V, which is constituted by:

[0015] - a circular pit whose slope at the junction with the branches of V is less than the slope of the branches of V and whose slope at its opposite end is almost perpendicular, and / or

[0016] - a narrow nose protruding towards the centre of the bag to form a nose, the narrow nose serving to slightly reduce the transverse section of the bag.

[0017] This intermediate region, in particular the circular pit, avoids the formation of vertical creases in the V-shaped portion.

[0018] In a preferred embodiment of the application, the bag is constituted of two faces which are joined together by their outer edges, in particular by welding the edges.

[0019] In a simple embodiment, the bag according to the application has an upper edge, a V-shaped lower edge and two side edges each connecting an end of the lower edge to a respective end of the upper edge, an intermediate region being interposed between the V-shaped lower edge and the side edges if necessary. The bag preferably has a substantially rectangular shape, the tip of the V being located in the centre of one of the small sides of the rectangle, the bag extending beyond the V-shaped lower edge on either side of the V until an outer lower edge parallel to the upper edge (11a), the outer lower edge (11c) preferably at least partially coinciding with the lower edge (13, 132) at the location of the tip of the V. The bag according to the application can also be realized by superimposing two rectangular faces made of a suitable plastic material and joining these two faces together by welding, gluing or any other suitable means along the side edges, the upper edge, the V-shaped lower edge and, if necessary, the outer lower edge, the fixing (welding, gluing, etc.) of the side edges preferably continuing up to the outer lower edge.

[0020] The fluid introduction line preferably opens into the bag at a location opposite the tip of the V, which ensures that the entire solid concentrate contained in the bag is penetrated by the dissolving water before the extraction fluid line, which itself opens into the location closest to the tip of the V, leaves the bag.

[0021] The extraction fluid line can comprise a tube whose first end is provided with a filter, the tube being sized so that the filter can be placed at a location closest to the tip of the V. This filter makes it possible to draw off the solution without taking away the solid particles.

[0022] The bag can be provided with a connector for connecting the bag to a hemodialysis generator, which connector passes through a first section of the introduction and extraction fluid lines, which first section extends by means of a tube mounted on its opposite ends by means of filters located closest to the V-shaped tip, which first section is preferably located at the opposite position of the tip of the V. The connector can be inserted into the edge of the bag further from the lower edge, preferably in the upper edge opposite the V-shaped lower edge. Another solution consists in inserting the connector into the wall of the bag at a distance from the V-shaped lower edge, preferably into the upper half.

[0023] The bag according to the present application is particularly suitable for hemodialysis (HD) and hemodiafiltration (HDF). It can contain bicarbonate to make a saturated solution for dialysis. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application is described in more detail below with the help of the accompanying drawings, in which:

[0025] Figure 1a is a schematic view of a bag at the end of the dissolution process according to the prior art;

[0026] Figure 1b is a schematic view of a bag at the end of the dissolution process according to the present application;

[0027] Figure 2a is a view of the lower part of an empty bag according to the prior art;

[0028] Figure 2b is a view of the lower part of an empty bag according to the present application;

[0029] Figure 3a is a side view of a bag filled according to the present application;

[0030] Figure 3b is a front view of a bag filled according to the present application; and

[0031] Figure 4 is a clear example of implementation of a bag according to the present application. DETAILED DESCRIPTION

[0032] For reasons of clarity, the description uses spatial references, for example "lower" or "upper", "high" or "low", "vertical" or "horizontal". These references are with respect to the orientation of the bag as shown in the figures, for example in the figures Figure 1a and 1b the bag with the connector placed high.

[0033] The bag (1) according to the present application, like the bag (9) of the prior art, is constituted by two rectangular lower flaps of a soft sheet made of plastic. For applications in the field of dialysis, the bag can be made of low-density polyethylene (PEBD), of a mixture of polyamide and low-density polyethylene (PA / PEBD) or of a mixture of low-density polyethylene and high-density polyethylene (PEBD / PEHD), or even of a double material. The two lower flaps are fixed together by their outer edges, so that the empty bag is flat at least in its lower part. The fixing is preferably achieved by welding, although other fixing modes such as gluing can also be envisaged. For reasons of clarity, the term "welding" will not be used in the following, although it does not involve a limiting feature, any other fixing mode compatible with the use of the bag, in particular gluing, being applicable to the present application. In the example described herein, the bag has two lateral edges (1 lb, 1 Id, 91b, 91d), an outer lower edge (1 lc, 91c) and an upper edge (1 la, 91a). The lateral edges, the outer lower edge and the upper edge are substantially straight when the bag is empty. Instead of using two lower flaps welded and overlapped at their outer edges, it is also possible to use a tubular wall closed at its two ends, for example by welding, or even a sheet folded in two and closed at its overlapped edges, in particular by welding. The overall shape of the bag (here rectangular) and the number of edges are not important. It is possible to envisage an overall shape of the bag that is trapezoidal, triangular, or even circular.

[0034] The extraction device (12, 92) is placed in one of the edges (1 la, 91a) of the bag, or in a wall of the bag at a distance from the edge. Generally, these extraction devices comprise two fluid lines, one for the introduction of water to dissolve the sodium bicarbonate and the other for the extraction of the obtained solution contained in the bag. In the example described herein, the extraction device is constituted by a connector (12, 92) of the type disclosed in patent application EP 1 344 550 A1. It is advantageous to combine the extraction device and the connection device to the hemodialysis generator. The connector (12, 92) is inserted in the upper edge (1 la, 91a). It is of course possible to envisage any other type of extraction device without having to make it necessarily assume the additional function of the connection device. Other possible implementation examples are two separate tubes inserted in the upper edge (1 la, 91a) as disclosed in US 4 561 110. These tubes can be inserted in two different edges, in particular in two opposite edges. It is also possible to envisage a single fluid line for the introduction of the dissolving water and for the extraction of the finished solution.

[0035] The two fluid lines of the connector (12, 92) lead into the upper part of the bag (1, 9). The extraction fluid line of the connector (12, 92) is equipped with a hose (121, 921) whose end is a filter (122, 922). The length of the hose is chosen so that the filter is placed in the lower part of the bag. The dissolved water is thus introduced into the upper part of the bag, penetrates the solid concentrate to saturate it, and the saturated solution passes through the filter and the hose to be extracted into the lower part.

[0036] To make the solid concentrate accumulate in as small a space as possible at the end of the process, the lateral section of the lower part of the bag is reduced. In the prior art bag (9), this reduction is achieved by implementing an inclined weld (93) between one of the two corners of the lower part of the bag (91e) and the opposite side edge (91d). The inclined weld has two sections with different slopes: the first section (931) close to the lower corner (91e) is less inclined than the second section (932) close to the side edge (91d) opposite the lower corner (91e). In the example presented here, the first section is inclined at about 20 degrees with respect to the horizontal (or the external lower edge 91c) and the second section is about 38 degrees. The 20-degree slope makes it possible to conform to the radius of curvature of the tube and to place the end of the filter in the corner of the bag, while the 38-degree slope makes it possible for the powder to fall as it dissolves. The filter (922) fixed at the end of the hose is on the first section and its end is also as close as possible to the lowest point (94). The second section is a compromise. Indeed, the greater the slope, the easier it is for the concentrate to slide along the inclined weld, but the greater the wasted space (933) between the inclined weld and the second corner (91f) of the lower part of the bag. Alternatively, to compensate for the wasted space while maintaining the same usable space, the height of the bag should be increased.

[0037] In addition, when the bag of the prior art is filled with solid concentrate and also during the dissolution process, it tends to deform into an asymmetry, so that a kind of fold appears in the wall of the bag. To ensure that the filter is on the first section (931) of the inclined weld and that its end is at the lowest point (94) of the bag, it is necessary to fix the tube (921) to the fluid line of the connector (92) opposite the corner (91e) in which the lowest point is located, otherwise there is a risk that the filter will not be located at the lowest point after the bag has deformed.

[0038] As the dissolution continues, the solid concentrate in the bag becomes less and less. Under the effect of gravity, the fixed concentrate tends to accumulate in the lower part of the bag. However, experience shows that at the end of the process, a part of the solid concentrate remains hanging on the inclined weld (93) of the wall of the bag, as Figure 1aAs shown schematically. It forms a kind of channel in the accumulated solids so that the dissolved water no longer penetrates the solid concentrate. Some studies carried out on hemodialysis bags show that between 2.1% and 21.6% of the solid concentrate (bicarbonate) remains at the end of the process, these values varying with the initial volume of the solid concentrate and the dissolution speed. This channel effect is particularly due to the fact that the dissolved water is introduced from the filter essentially vertically, which is not conducive to bringing the solid concentrate to the lowest point where the filter is located. The presence of the tube (921) along a portion of the inclined weld also facilitates the retention of solids. To compensate for this portion of product that is retained, it is necessary to provide more solid concentrate than is theoretically required. The large range observed (2.1% to 21.6%) demonstrates how the quantity extracted is not reproducible. It is therefore necessary to have an excess of product sufficient to be able to obtain the nominal volume of solution in all cases. In practice, the excess portion is between 100 and 200 grams depending on the size of the bag.

[0039] The bag according to the application is developed to greatly reduce the excess product added to the bag to guarantee the nominal volume of the solution. The lower edge of the bag (1) according to the application is itself V-shaped, the V-shaped tip being opposite the upper edge (11a) and constituting the lowest point (14) of the bag. The two edges (13) forming the branches of the V are constituted by two inclined welds (13) extending between a substantially intermediate position of the outer lower edge (11c) and one of the side edges (11b, 11d). At the junction between the two branches of the V, the two inclined welds (13) are separated by a rounded, in particular circular-arc, junction area (132). This junction area constitutes the lowest point (14) of the bag. By moving this lowest point of the corner (91e) of the bag to the center of the lower edge (11c) and by choosing two inclined welds (13) instead of one (93), it is possible to choose a greater inclination while having a relatively small wasted space (131) between the inclined weld (13) and the corresponding lower corner (11e, 11f). It is of course also possible to cut the material forming the wasted space (131), but this additional step is not necessary. More simply, two rectangular lower flaps are used and not only the edges (11a, 11b, 13, 132, 13, 11d) forming the bag are welded but also the outer lower edge (11c), then the side edges until the outer lower edge (11c) to form the lower corners (11e, 11f). This avoids the lower flaps being empty at the wasted space (131). In addition, the welding of the corners makes these parts rigid so that they do not tend to fold in on themselves. In Figure 2b It can be seen in that the outer lower edge (11c) and the lower part of the junction area (132) forming the tip of the V coincide with the lowest point of the bag.

[0040] In addition, since the bag is symmetrical, it does not have the same problem as the bag in the prior art (seeFigure 1a ) such that asymmetric deformation occurs. The length of the tube (121) can be chosen such that the filter is located only at one of the inclined seams (13) of the wall of the bag. The tube (121) thus does not cause the solid to back up along the seam as in the prior art bags.

[0041] The angle (a) between the two branches (13) of the V is preferably between 65° and 75°.

[0042] In order to follow the natural deformation of the attached bag when it is filled and to avoid the formation of creases and the resulting tensioned areas, an intermediate area (15) can be provided between the apex of the two branches (13) of the V and the side edges (lib, lid). In Figure 1b and 2b In the example presented, this intermediate area is composed of a palier (151) which is preferably a circular arc, and a narrow nose (152). The slope of the palier joining the apex of the inclined seam (13) regularly increases until it is substantially perpendicular. Here, the width of the edge of the bag is at least equal to the general width of the side edges (lib, lid) outside this intermediate area. The palier (151) thus leaves room for a narrow nose (152) which continues the concavity at the lower part by separating towards the centre of the bag until a nose (152') and from which the edge of the bag separates again from the centre of the bag. The length of the edge between the junction with the palier (151) and the nose is preferably shorter than the length between the nose and the junction with the side edges (lib, lid), that is to say, the first part is more inclined than the second part (with respect to the perpendicular). If the outer contour of the empty bag is rectangular, the width of the edge of the bag in this narrow nose (152) increases more gently before decreasing again until the nose until it returns to the width of the side edges (lib, lid). The palier (151) and the beginning of the narrow nose (152) together form a kind of cavity (153). The narrow nose does not need to extend to the upper edge (lib). It is sufficient to start a few centimetres from the apex of the branches of the V. When the bag is filled with dry sodium bicarbonate but mainly salt and dissolved water, the bag swells by about 3 to 4 centimetres which exerts a pressure on the welded edges. The presence of the cavity (153) and the narrow nose (152) helps to better distribute the stresses and pressures on the welded edges. The rounded shape of the cavity (153) also makes it possible to reduce the risk of leaks appearing for example at the corner parts.

[0043] As Figure 4The detailed, non-limiting example, for a bag with a height of 280 mm and a width of 122 mm, shows that the general width of the welded edges (11a-d, 13, 132, 151) is approximately 4 mm (slightly larger in the nose of a narrow nose piece), the circular joint area forms the tip of a V with a width of approximately 15 mm, and the welded edge (13) (or the outer lower edge 11c) is inclined at approximately 55° relative to the horizontal direction, i.e., the angle (α) between the branches (13) of the V is 70°. In the following description of the example, reference is made to the 0 mm rib corresponding to the bottom of the joint area. This is the lowest point of the bag (14). The inclined weld extends between the end of the joint area, 7.5 mm from the center of the lower edge (11b), and the 50 mm rib, 42 mm from the center of the lower edge (11b). Between the 50 mm rib and the 120 mm rib, the inclined weld (13) leaves space for the weld in the intermediate region (15) between the inclined weld (13) and the welds of the side edges (11b, 11d). This intermediate region begins at a circular pit (151) that extends to the 64 mm rib, 56 mm from the center of the lower edge. This is followed by a narrow nose (152) in which the width of the bag edge increases to the 75 mm rib (coude) (152') before continuing to decrease to the 120 mm rib. The thickness at the 120 mm rib is the same as the remaining portion of the side edge, approximately 4 mm. The radius of curvature of cavity (153) is 14 mm.

[0044] The welds forming the lower part of the bag (11b, 152, 151, 13, 132, 13, 151, 152, 11d) are made to trace a continuous trajectory inside the bag without any angles that could cause solid products to back up, interfere with liquid flow, and / or cause the bag to deform.

[0045] exist Figure 1b and 2b In the example shown, the tip (132) of the V is located at the center of the outer lower edge (11c) of the bag (1), and therefore at the center of the V-shaped edge (13, 132). The bag is symmetrical, so that the connector (12) does not need to be oriented such that the filter (122) is located at a specific point, as is required for bags in the prior art. In some cases, the tip of the V can be moved to separate it from the center of the outer lower edge (11c), without having to do so until one of the corners (11e, 11f).

[0046] The study carried out on the bags of the present invention filled with bicarbonate for hemodialysis showed that only 1,2% and 5,2% of the solid product did not dissolve at the end of the process. Thanks to the bag of the present invention, (1 ), whose inclined weld (13) has a large angle with respect to the horizontal (55° in the example presented, as opposed to 38° in the bags of the prior art), the excess product to be provided in the bag to ensure the nominal volume of the solution can be greatly reduced. In the example of the bag for hemodialysis, 50 g of bicarbonate are saved for the 500 g and 600 g bags, and 100 g of bicarbonate are saved for the 900 g bag. This represents a reduction of 50% in the losses. Not only due to the geometry subtracted, but also due to the smaller amount of bicarbonate contained in the bag, the dimensions of the bag, and in particular its height, can be reduced. In the case presented here, the height of the bag of the present invention is 4 cm less than the bag of the prior art for the same width. This allows not only the saving of the manufacturing material of the bag, but also the saving of storage space for the empty bags before filling and for the bags ready for use.

[0047] LIST OF REFERENCE NUMBERS

[0048] [Table 1 ]

[0049] 1. Bag of the present invention

[0050] 11a-d Side edges of the bag

[0051] 11e-f Lower corners

[0052] 12 Extraction means

[0053] 121 Hose

[0054] 122 Filter

[0055] 13 Inclined edge

[0056] 131 Wasted space

[0057] 132 Joining area

[0058] 14 Lowest point of the bag

[0059] 15 Intermediate area

[0060] 151 Pit

[0061] 152 Nose

[0062] 152' Nose of the nose

[0063] 153 Cavity

[0064] α Angle between branches of V

[0065] 9 Bag of the prior art

[0066] 91a-d side edges of a bag in the prior art

[0067] 91e first lower corner from which the beveled edge emerges

[0068] 91f second lower corner

[0069] 92 extraction means

[0070] 921 hose

[0071] 922 filter

[0072] 93 beveled edge

[0073] 931 first section with the smallest inclination

[0074] 932 second section with the largest inclination

[0075] 933 wasted space

[0076] 94 lowest point of the bag

Claims

1. A bag (1) consisting of soft walls, equipped with an introduction fluid line for the introduction of solvated water and an extraction fluid line for the extraction of the solution obtained, characterized in that, The inside of the bag has a lower edge (13, 132) which is substantially V-shaped, the tip (132) of the V being further from the centre of the bag than the branches of the V, the extraction fluid line leading to a position in the bag closest to the tip (132, 14) of the V.

2. A bag (1) according to claim 1, characterized in that The junction area (132) between the two branches of the V (13) is rounded.

3. A bag (1) according to claim 1 or 2, characterized in that The two branches of the V (13) have the same inclination and / or the junction area (132) between the two branches of the V (13) is located at the centre of the lower edge (13, 132).

4. Bag (1) according to one of the preceding claims, characterized in that The angle (a) between the two branches of the V (13) is between 65° and 75°.

5. Bag (1) according to one of the preceding claims, characterized in that The branches of the V (13) are obtained by welding the bag itself.

6. A bag (1) according to one of the preceding claims, characterised in that The lower edge (13, 132) is followed, opposite the tip of the V, by an intermediate area (15) consisting of: - a pocket (151) whose slope at the junction with the branches of the V (13) is less than the slope of the branches of the V (13) and whose slope at the opposite end approaches the perpendicular, and / or - a narrow nose (152) which bulges towards the centre of the bag to form a nose tip.

7. A bag (1) according to one of the preceding claims, characterised in that The bag consists of two lower flaps joined together by their outer edges, preferably by welding the outer edges.

8. A bag (1) according to one of the preceding claims, characterised in that The inside of the bag has an upper edge (11a), a lower edge (13, 132) which is V-shaped, and two side edges (lib, lid) each connecting an end of the lower edge to a respective end of the upper edge, an intermediate area (15) being inserted between the V-shaped lower edge (13, 132) and the side edges (lib, lid) if necessary.

9. A bag (1) according to claim 8, characterized in that The bag is generally rectangular, the tip of the V being located at the middle of one of the small sides of the rectangle, the bag extending beyond the V-shaped lower edge on either side of the V until an outer lower edge (11c) which is parallel to the upper edge (11a), the outer lower edge (11c) preferably at least partially coinciding with the lower edge (13, 132) at the tip (132) of the V, the side edges (lib, lid) preferably extending until the outer lower edge (11c).

10. A bag (1) according to one of the preceding claims, characterized in that The introduction fluid line leads to a position in the bag opposite the tip of the V.

11. Bag (1) according to one of the preceding claims, characterized in that The extraction fluid line comprises a tube (121) the first end of which is equipped with a filter (122), the tube being sized to allow the filter to be placed at a position closest to the tip (132) of the V.

12. Bag (1) according to one of the preceding claims, characterized in that The bag is equipped with a connector (12) for connecting it to a haemodialysis generator, the first segment of the introduction fluid line and of the extraction fluid line passing through the connector, the first segment preferably being located opposite the tip of the V, the first segment extending by means of a tube (121) equipped at its opposite ends with filters (122) located at a position closest to the tip (132) of the V.

13. A bag (1) according to claim 12, characterized in that Said connector (12) is inserted in the edge of the bag at a distance from the lower edge (13, 132) of the V, preferably in the upper edge (11a) opposite the lower edge of the V, or said connector is inserted in the wall of the bag at a distance from the lower edge (13, 132) of the V.

14. A bag (1) according to one of the preceding claims, characterized in that The bag contains bicarbonate for the preparation of a saturated solution for dialysis.

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