US 20040232171 A1
Apparatus for delivering sensitive liquid media, such as solutions, dispersions, suspensions, and the like, which comprises at least one flexible container having an outlet and enclosing a liquid medium. A pressure chamber which accommodates the container. The outlet of the container can be led through the chamber wall. A pressure source can be connected to the pressure chamber and the pressure chamber can be pressurized thereby.
1. An apparatus for delivering liquid media, comprising
at least one flexible container which has an outlet and encloses a liquid medium,
a pressure chamber which accommodates the container and from which the outlet from the container can be led, and
a pressure source connection to the pressure chamber by which the pressure chamber can be pressurized.
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 The invention relates to an apparatus for delivering sensitive liquid media from a sealed flexible container using a pressurized chamber in which the container is held.
 In the medical sector, it is repeatedly necessary to deliver sensitive liquid media such as solutions, dispersions, suspensions and the like, for example protein solutions, or the like. It is known to introduce the media into flexible containers and to suspend these, for example, at a specific height, in order to supply the medium to a use, for example a filtration device, under a positive pressure depending on the height of the suspension. It is also known to conduct a gaseous medium into the container with the liquid medium, to build up a positive pressure in the container and to drive out the liquid medium. Finally, it is known to use peristaltic pumps to deliver such sensitive liquid media.
 Disadvantages have occurred in the delivery of the liquid media. If the container with the medium is suspended at a certain height, then the delivery pressure depends on the difference in height between the container and a user of the medium. If the container itself is inflated with a gas in order to build up a positive pressure to deliver the liquid medium, then it is possible for leaks in the container to occur and for the liquid medium to emerge. Even bursting of the container cannot be ruled out. If peristaltic pumps are used to deliver the liquid medium, then firstly sensitive constituent parts of the liquid medium are loaded mechanically by the peristaltic pump. Moreover, in particular with a low positive pressure for delivering the liquid medium, it is often a problem to set a defined positive pressure. Finally, pulsations occur in the medium delivered, which is often undesired.
 It is therefore an object of the invention to provide an apparatus for delivering sensitive liquid media which does not have the above described disadvantages.
 In order to achieve this object, an apparatus is proposed which has the following features. A sensitive liquid medium is held in a flexible container with an outlet and from which medium is forced upon pressure being applied to the container. It is distinguished by providing a pressure chamber into which the flexible container filled with the liquid medium can be introduced. A pressure source is connected to the pressure chamber, acts on the pressure chamber with a positive pressure and therefore compresses the flexible container. The medium is thereby driven out of the container. It is particularly advantageous that the pressure can be set very accurately and can be easily monitored.
 The invention is explained in more detail in the following text using the drawing, which is a perspective view of a pressure chamber formed as a pressure cabinet.
 The pressure cabinet 1 shown in the single Figure has an interior which serves as a pressure chamber 3, into which there is introduced a flexible container 5 in which there is a sensitive liquid medium 7.
 The container 5 is preferably formed as a sterile disposable bag, which is therefore used only once, so the problems of cleaning and disinfection of the container which are associated with refilling are avoided.
 The container 5 has an outlet 9, from which a hose 11 exits. The hose discharges the liquid medium 7 from the container 5. Otherwise, the container 5 is closed off completely from the outside, so that the medium 7 cannot be contaminated.
 The container 5 is suspended in the interior of the pressure cabinet 1 in a suitable way. Here, it is illustrated with a conventional cutout 13, which is provided in a double-walled region of the container 5, so that there no connection is provided between the liquid medium 7 and the outside. Two hooks 15, which hold the container 5 securely in the interior of the pressure cabinet 1, engage in the cutout 13.
 However, such a suspension of the container 5 is necessary only when the pressure cabinet 1 is operated upright, which should be the normal case. However, should the cabinet be oriented horizontal, the container 5 would be held securely by the side walls 17, 19, 21 and 23, so that further fixing of the container 5 in the pressure chamber 3 would not be required.
 The hooks 15 can be fixed to a rear wall 25 of the pressure cabinet 1, or else from the inside to the upper side wall 17. It is merely critical that the container 5 is held in a desired position here, so that it does not kink the hose 11 on account of the inherent weight of the container.
 The lower side wall 21 of the cabinet has a cutout 27, which leads from the pressure chamber 3 to the outside and accommodates the hose 11. Preferably, an elastic protective layer, for example a rubber grommet 29, prevents the hose 11 chafing through.
 Fitted to one side wall 23, for example via hinges 33 and 35, or the like, is a door 31 which when closed, closes off the pressure chamber 3 in a pressure-tight manner.
 On its side facing the pressure chamber 3, the door may be provided with a circumferential seal 37, which interacts with the front sides of the side walls 17, 19, 21 and 23 to close off the pressure chamber 3 in a pressure-tight manner.
 On the bottom of the door 31, a protective layer 38 may again be provided, which holds the hose 11 securely in the cutout 27 without chafing through it.
 On one side wall, here wall 19, there is a pressure connection 39, via which the pressure chamber 3 can be connected at 40 to a pressure source 42. When the door 31 is closed, the pressure source can place the pressure chamber 3 and therefore also the flexible container 5 under a positive pressure. Also provided on the side wall 19 are a pressure indicator 41 and a safety valve 43.
 Finally, the apparatus 1 can also be provided with a vibrating unit, to ensure that the medium 7 present in the container 5 can be kept continuously moving or during predeterminable time periods, in order to avoid settling of the substances present in the medium.
 The vibrating unit can act directly on the container 5 and can be accommodated in the pressure chamber 3. However, the pressure cabinet 1 is preferably placed on a vibrating table 44 and therefore subjected in its entirety to a movement which acts on the medium 7 in the container 5.
 In the following text, operation of the apparatus for delivering sensitive liquid media will be described in more detail:
 In the container 5 there is a sensitive medium, for example a solution, dispersion or suspension, which should not be subjected to any mechanical loading as might be provided, for example, when the medium is pumped with a peristaltic pump.
 The container 5 itself is at least in part of flexible material, so that a positive pressure acting on the container 5 acts on the liquid medium 7 inside the container and drives the medium out via the outlet 9 and the hose 11.
 The container 5 is introduced into the interior of the pressure cabinet 1, that is into the pressure chamber 3, and is preferably fixed to the hooks 15. The hose 11 is led through the cutout 27, which is dimensioned such that the hose 11 is not crushed when the door 31 is closed. The hose 11 may consist of a flexible material which closes off the cutout 27 in a pressure-tight manner. However, provision is preferably made here for a protective layer 29, which interacts with the protective layer 38 on the door 31 in such a way that, when the door is closed, the hose 11 is enclosed completely and the pressure chamber 3 is closed off pressure-tight from the outside. In addition, the seal 37 interacts with the side walls 17, 19, 21 and 23 here, so that the pressure chamber 3 is closed off completely when the door 31 is closed.
 Then, a positive pressure is built up in the interior of the apparatus, here in the pressure cabinet 1, through the pressure connection 39. A gaseous medium is preferably conducted into the pressure chamber 3, since such a medium escapes quickly when the door 31 is opened. However, it would also be conceivable to conduct a liquid medium into the chamber 3, since the pressure medium is isolated by the container 5 from the liquid medium 7 in the interior of the container.
 Nitrogen is preferably conducted into the pressure chamber 3 from the source 42, since would not impair the sensitive medium 7 in the interior of the container 5, even in the event of any leaks in the container. In addition, the inside of the pressure cabinet 1 is not contaminated by this gas.
 The positive pressure acting in the pressure chamber 3 can be set by a monitoring device in terms of level and in terms of the pressure variation provided over time. For this purpose, suitable backing up of the pressure source can be provided. Monitoring of the pressure chamber 3 can be implemented by a monitoring device which includes the pressure indicator 41 and the safety valve 43. The valve prevents a hazardous positive pressure in the pressure chamber 3 and therefore prevents the door 31 bursting open undesirably. However, it is particularly important that the medium 7 is discharged from the container 5 only at a defined pressure and that is non-hazardous for the medium 7 and for its processing.
 The safety valve 43 preferably can be set to a desired pressure, in order to employ the apparatus readily for various delivery purposes. For example, when filtering sensitive media, a filtration pressure of about 0.2 bar is used. Accordingly, the safety valve 43 must then be set to this pressure, in order to enable use of the apparatus for filtering.
 In principle, it is therefore possible, by use of an appropriate monitoring device and with adjustable pressure sources, to maintain a desired pressure in the pressure chamber 3 or else to maintain different pressure values at different times. The apparatus can therefore be employed universally, that is to say not just for filtering media but for various processing and delivery purposes, and possibly also as a metering device when administering medicaments.
 In the embodiment illustrated, the pressure chamber 3 is designed to accommodate a single container 5. However, it is possible to subdivide the pressure chamber and to allocate different pressure values to various regions of the pressure chamber which are delimited from one another in a pressure-tight manner, and also possible to accommodate different containers in these regions.
 It is critical that the medium 7 can be delivered and discharged from the container 5 without contact. Pressure acting externally on the flexible container 5 delivers the medium 7 out of the container 5 via the outlet 9 and the hose 11 and supplies medium to various intended uses.
 The pressure chamber 3 is not brought into contact with the medium 7, so that the replacement of containers with different media is easily possible, without need for a complicated disinfection process. The media from different containers do not come into contact with either the interior or the pressure chamber of the pressure cabinet nor with any appliances connected to the pressure chamber, here the pressure connection 39, the pressure indicator 41 or the safety valve 43. If the pressure chamber 3 is preferably acted on with nitrogen at a positive pressure, it is possible to ensure that the medium 7 is not impaired, even if the container 5 should have a leaky point and the pressure medium should penetrate into the interior of the container 5.
 After all this, it is obvious that the apparatus is constructed very simply and therefore can operate virtually without fault. This leads to very safe use of the apparatus described here, which is of critical importance in particular in the medical sector.
 In order to be able to employ the apparatus even at very low positive pressure values, the pressure connection 39 can also be provided with a pressure reducing valve. This leads to additional safety if the apparatus, for example, is used in a filtration in which a positive pressure of only 0.2 bar is desired.
 The requirements for the container 5 are in no way special. It is possible to use usual sterile disposable bags such as are on the market. No kind of adaptation of the container is therefore required during its use in the apparatus described here.
 Even in the case when the medium must to be kept moving continuously, no special precautions are required here. The pressure cabinet 1 can be placed on conventional vibrating tables, which then act on the medium 7 with the vibrating movement. Since the pressure cabinet 1 is constructed very simply and ruggedly, no detriment to it are to be expected when a vibrating table is used.
 Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.