Device for securing a pressure sensor to a container

Abstract

The invention relates to a single-use device (1) for securing a pressure sensor (2) to a container (20). A first end region (2a) of the pressure sensor (2) is provided with a pressure-sensitive measuring diaphragm (3), via which the pressure of the medium (21) located in the container (20) can be determined, wherein a tubular component (4) is provided which can be coupled to the container (20), and the tubular component (4) has a connecting piece (5), the inner surface (7) of which is provided with a radial stop edge (9). A flexible diaphragm (10) which closes the connecting piece (5) in a gas-tight manner is installed on the radial stop edge (9), and a cup-shaped mounting (11) is provided in which a second end region (2b) of the pressure sensor (2) can be placed, said second end region facing away from the pressure-sensitive measuring diaphragm (3). The cup-shaped mounting (11) and the connecting piece (5) can be locked via a corresponding securing mechanism (12), and the connecting piece (5) and the cup-shaped mounting (11) are designed such that in the installed state, the pressure-sensitive measuring diaphragm (3) of the pressure sensor (2) is in direct proximity to the flexible diaphragm (10).

Description

[0001] Device for attaching a pressure sensor to a container

[0002] The invention relates to a device, in particular a disposable device or a disposable adapter, for attaching a pressure sensor to a container or a receptacle. Preferably, the pressure sensor is reusable, while the container is preferably disposable.

[0003] Single-use technology is increasingly being used in many industrial processes in the pharmaceutical, biological, biochemical, and biotechnological sectors. Flexible containers, such as bags, tubes, or fermenters, are used as containers or bioreactors. The disposable containers are equipped with inlet and outlet lines designed as flexible tubes; alternatively, inflexible pipe sections are also used in the inlet and outlet lines.

[0004] The aforementioned processes take place in a system isolated from the surrounding environment. Single-use technology has the advantage that the disposable containers used are disposed of after the process is completed. This avoids complex – and potentially critical – cleaning and sterilization procedures. Furthermore, the use of disposable containers eliminates the risk of cross-contamination, which increases process reliability.

[0005] To monitor the processes taking place in disposable containers, a wide variety of physical and / or chemical process variables of the media used are recorded. State-of-the-art sensors are preferably used. Sensors used in single-use technology can be roughly divided into two classes: invasive sensors and non-invasive sensors. While an invasive sensor is positioned inside the disposable container, with at least the measuring element coming into direct contact with the medium to be measured, a non-invasive sensor—isolated from the medium—is coupled to the outside of the disposable container.

[0006] With invasive sensors, coupling to the medium is usually easier than with non-invasive sensors. However, invasive sensors must be disposed of or radioactively sterilized after use. Since radioactive sterilization typically erases the sensor memory or even damages the electronics, at least the software must be reloaded. With non-invasive sensors, sterilization is unnecessary; they can therefore be used iteratively for multiple processes running in disposable containers without great effort.

[0007] A challenge with non-invasive sensors is attaching the sensor to the disposable container. These disposable containers are typically made of a flexible plastic with low mechanical dimensional stability. Therefore, detachably attaching a compact sensor to a flexible disposable container that is intended to deliver reproducible measurement results is not readily feasible.

[0008] A solution disclosed in US Pat. No. 10,836,990 B2 couples a reusable pressure sensor to a single-use container or a disposable bioreactor via an interface. The interface comprises a dimensionally stable polymer flange that can be connected to a wall of the disposable container. The polymer flange consists of a side wall and an interface designed to accommodate a separate, deflectable, polymer membrane. Furthermore, a region is provided that is sealingly coupled to the polymer flange. This region is designed to allow the coupling of a reusable measuring device. The interface for coupling a measuring device to a bioreactor, which is proposed in the US patent, consists of a large number of individual components and is therefore quite complex.The present invention is based on the object of proposing a simple device for connecting a non-invasive pressure sensor to a disposable container. Furthermore, the invention is based on the object of proposing a simple method for manufacturing a device according to the invention.

[0009] The problem is solved by a device, in particular a disposable device, for attaching a pressure sensor to a container, wherein the pressure sensor is provided in a first end region with a pressure-sensitive measuring diaphragm, via which the pressure of the medium in the container can be determined. Furthermore, a tubular component is provided which can be coupled to the container. The tubular component has a nozzle, on the inner surface of which a radial stop edge is provided. A flexible diaphragm is attached to the radial stop edge, which seals the nozzle in a gas-tight manner. By means of a cup-shaped holder, the pressure sensor can be placed in the second end region of the pressure sensor facing away from the pressure-sensitive measuring diaphragm. The holder and the nozzle can be connected to one another via a corresponding fastening mechanism, wherein the connection is preferably designed to be detachable.Furthermore, the nozzle and the holder are designed in such a way that the pressure-sensitive measuring membrane of the pressure sensor is arranged in the immediate vicinity of the flexible membrane when mounted.

[0010] The pressure-sensitive measuring diaphragm is preferably a ceramic measuring diaphragm. Sensors with a ceramic measuring diaphragm are developed, offered, and distributed by the Endress+Hauser Group in a wide variety of designs.

[0011] High-quality pressure sensors are relatively expensive. Therefore, the pressure sensor is designed to be reusable and removed from the container after the process is complete via a detachable fastening mechanism. Since the sensor is isolated from the process taking place in the container during measurement / monitoring, subsequent radioactive sterilization, which would entail the aforementioned disadvantage of erasing the memory or destroying the electronics, is unnecessary.

[0012] An advantageous embodiment of the device according to the invention provides an annular lip seal which, in the assembled state, is placed between the outer surface of the first end region of the pressure sensor and the corresponding inner surface of the nozzle.

[0013] The lip seal is designed to equalize pressure in the event of overpressure occurring between the pressure-sensitive measuring diaphragm and the annular lip seal. This regularly occurs during assembly when the cup-shaped holder with the pressure sensor is attached to the nozzle. If the excess air cannot escape, overpressure builds up between the flexible diaphragm and the measuring diaphragm, distorting the actual pressure prevailing in the process. Due to the use of an annular lip seal, excess air can escape automatically in the inventive solution, so that no undesirable overpressure is detected at the measuring diaphragm. This is extremely important, since pressure at the measuring diaphragm that does not originate from the process would inevitably lead to a measurement error.

[0014] Preferably, the annular lip seal is designed to prevent pressure equalization in the event of a negative pressure prevailing between the pressure-sensitive measuring diaphragm and the annular lip seal. Thus, no air is drawn from outside into the space between the measuring diaphragm, the flexible diaphragm, and the lip seal to cause pressure equalization. This makes it possible to measure both positive and negative pressures with the proposed invention using a non-invasive pressure sensor.

[0015] One embodiment of the device according to the invention proposes that the annular lip seal have a bent portion in its edge region, which is directed away from the pressure-sensitive measuring element. The bent portion of the annular lip seal preferably tapers toward the outer edge. The gap formed between the edge region of the annular lip seal and the inner surface of the nozzle allows excess air to escape easily in the event of overpressure, while in the event of negative pressure, the intake of air from outside is prevented, since the outer edge region of the lip seal fits tightly against the corresponding inner surface of the nozzle.

[0016] A further development of the device according to the invention proposes that the nozzle and the holder are designed such that the pressure-sensitive measuring diaphragm of the pressure sensor, in the mounted state, contacts the flexible diaphragm essentially without force transmission. Alternatively, it is provided that the nozzle and the holder are designed such that the pressure-sensitive measuring diaphragm of the pressure sensor, in the mounted state, has a maximum distance of 1 mm from the pressure-sensitive measuring diaphragm. The flexible diaphragm is preferably designed such that the measurement error resulting from the fact that the pressure of the medium can only be correctly measured by the pressure sensor when the flexible diaphragm is in contact with the pressure-sensitive measuring diaphragm, lies within the range of the measurement error of the pressure measuring device.

[0017] Furthermore, according to a further development of the device according to the invention, it is proposed that the holder and the nozzle be connected to one another via corresponding fastening elements on the cup-shaped holder and the nozzle. The fastening elements can be, for example, a circumferential locking groove and a corresponding locking lug. A screw cap offers another possibility. Other connection options are known to a technically qualified person. Preferably, the attachment of the cup-shaped holder to the nozzle is designed so that it can be carried out with one hand.

[0018] Furthermore, the tubular component is provided with connecting elements at both ends for connection to, for example, the container's hoses. The container is preferably a disposable container that can be properly disposed of after the process is completed. This eliminates the need for a potentially complex cleaning and sterilization process.

[0019] An embodiment of the device according to the invention provides that the components of the device are preferably made of a biocompatible material, for example polyethylene.

[0020] Furthermore, the object underlying the invention is achieved by a method for manufacturing a device as described above in various embodiments. The following method steps are proposed:

[0021] • the flexible membrane is attached to the radial stop edge located on the inner surface of the nozzle of the tubular component, the pressure-tight attachment being irreversible;

[0022] • the modified tubular component is sealed in a bag and sterilized using radioactive radiation.

[0023] Preferably, the flexible membrane is attached to the radial stop edge or on the radial stop edge using a welding or gluing process.

[0024] The invention is explained in more detail with reference to the following figures. They show:

[0025] Fig. 1 : a longitudinal section through an embodiment of the device according to the invention,

[0026] Fig. 2: a perspective view of an embodiment of the lip seal which can be used in conjunction with the device according to the invention, and

[0027] Fig. 3: a cross-section through the lip seal according to the marking III-III in Fig. 2.

[0028] Fig. 1 shows a longitudinal section through an embodiment of the disposable device 1 according to the invention for coupling the pressure sensor 2 to the container 20. The pressure sensor 2 is preferably a ceramic pressure sensor 2 which is pressure-tightly sealed in a first end region 2a with a pressure-sensitive measuring membrane 3.

[0029] Ceramic materials used for the production of a pressure-sensitive

[0030] Membrane are well known from the state of the art.

[0031] The pressure sensor 2 determines the pressure of the medium 21 located in the container 20 via the pressure-sensitive measuring membrane 3. The container 20 is shown schematically in Fig. 1. The supply and discharge lines for coupling the container 20 to the device 1 according to the invention are not shown in Fig. 1.

[0032] The device 1 according to the invention comprises a tubular component 4 with fastening elements 6a, 6b in the edge regions. The tubular component 4 is connected to the container 20 via the fastening elements 6a, 6b and corresponding fastening elements (not shown separately in Fig. 1) on the supply and discharge lines of the container 21.

[0033] The tubular component 4 has a nozzle 5, on whose inner surface 7 a radial stop edge 9 is provided. The stop edge 9 is created, for example, by appropriate milling or casting of the nozzle 5. A flexible membrane 10 is attached to—or in the case shown, onto—the radial stop edge 9, which seals the nozzle 5 in a gas-tight manner.

[0034] Furthermore, a cup-shaped holder 11 is provided, in which a second end region 2b of the pressure sensor 2, facing away from the pressure-sensitive measuring diaphragm 3, can be placed. The cup-shaped holder 11 and the nozzle 5 can be connected to one another via a corresponding fastening mechanism 12a, 12b. In the illustrated case, the fastening mechanism 12a, 12b is a circumferential locking lug 12b on the inner surface 18 of the lower edge region of the cup-shaped holder 11, which, when mounted, engages in a corresponding locking groove 12a on the outer surface 8 of the nozzle 5. Alternatively, the connection can also be established, for example, via a screw connection. The connection of the two components 11, 5 is preferably designed so that it can be carried out with one hand.

[0035] The nozzle 5 and the cup-shaped holder 11 are designed such that the pressure-sensitive measuring membrane 3 of the pressure sensor 2 is arranged in the immediate vicinity of the flexible membrane 10 in the mounted state. In connection with the solution according to the invention, "immediately" preferably means that the flexible membrane 10 touches the pressure-sensitive measuring membrane 3 of the pressure sensor 2 in the mounted state without prestress, or that it is spaced from it by a maximum of 1 mm.

[0036] Furthermore, an annular lip seal 13 is provided, which in the assembled state is placed between the outer surface 17 of the first end region 2a of the pressure sensor 2 and the corresponding inner surface 7 of the nozzle 5. The annular lip seal 13 is designed such that, in the event of an overpressure prevailing between the pressure-sensitive measuring diaphragm 3, the flexible diaphragm 10 and the annular lip seal 13, it creates a pressure equalization by allowing the excess air to escape through a gap between the lip seal 13 bent up in the edge region 15 and the inner surface 7 of the nozzle 5. The annular lip seal 13 behaves differently in the event of a negative pressure: If a negative pressure occurs in the space between the pressure-sensitive measuring diaphragm 3, the flexible diaphragm 10 and the annular lip seal 13, the edge region orThe upturned portion 15 of the lip seal 13 rests against the inner surface 7 of the nozzle 5, effectively preventing pressure equalization. Thus, when a negative pressure occurs, no air is sucked from outside into the space defined by the flexible membrane 10 and the lip seal 13. The upturned portion 15 and the tapered portion 16 of the lip seal in the outer edge area are clearly visible in Fig. 2.

[0037] An advantageous embodiment of the lip seal 13 can be seen in perspective view in Fig. 2. Fig. 3 shows a cross section through the lip seal 13 according to the marking III-III in Fig. 2. List of reference symbols

[0038] 1 disposable device, disposable adapter

[0039] 2 pressure sensor

[0040] 2a first end area of ​​the pressure sensor

[0041] 2b second end area of ​​the pressure sensor

[0042] 3 pressure-sensitive measuring membranes

[0043] 4 tubular component

[0044] 5 nozzles

[0045] 6a first coupling area

[0046] 6b second coupling area

[0047] 7 Inner surface of the nozzle

[0048] 8 Outer surface of the nozzle

[0049] 9 radial stop edge

[0050] 10 flexible membrane

[0051] 11 cup-shaped holder

[0052] 12 Fastening mechanism

[0053] 12a locking groove

[0054] 12b locking lug

[0055] 13 annular lip seal

[0056] 14 outer edge area of ​​the annular lip seal

[0057] 15 Bending of the lip seal

[0058] 16 Rejuvenation of the lip seal

[0059] 17 Outer surface of the pressure sensor

[0060] 18 Inner surface of the cup-shaped holder

[0061] 19 cables

[0062] 20 containers

[0063] 21 Medium

Claims

Patent claims 1. Disposable device (1) for fastening a pressure sensor (2) to a container (20), wherein the pressure sensor (2) is provided in a first end region (2a) with a pressure-sensitive measuring membrane (3), via which the pressure of the medium (21) in the container (20) can be determined, wherein a tubular component (4) is provided which can be coupled to the container (20), wherein the tubular component (4) has a nozzle (5), on the inner surface (7) of which a radial stop edge (9) is provided, wherein a flexible membrane (10) is attached to the radial stop edge (9) and closes the nozzle (5) in a gas-tight manner, wherein a cup-shaped holder (11) is provided, in which a second end region (2b) of the pressure sensor (2), facing away from the pressure-sensitive measuring membrane (3), can be placed, wherein the cup-shaped holder (11 ) and the nozzle (5) can be locked via a corresponding fastening mechanism (12),wherein the nozzle (5) and the cup-shaped holder (11) are designed such that the pressure-sensitive measuring membrane (3) of the pressure sensor (2) is arranged in the immediate vicinity of the flexible membrane (10) in the mounted state.

2. Device according to claim 1, wherein an annular lip seal (13) is provided which, in the assembled state, is placed between the outer surface (17) of the first end region (2a) of the pressure sensor (2) and the corresponding inner surface (7) of the nozzle (5).

3. Device according to claim 2, wherein the annular lip seal (13) is designed such that it creates a pressure equalization in the event of an overpressure prevailing between the pressure-sensitive measuring membrane (3) and the annular lip seal (13).

4. Device according to claim 2 or 3, wherein the annular lip seal (13) is designed such that it prevents pressure equalization in the event of a negative pressure prevailing between the pressure-sensitive measuring diaphragm (3) and the annular lip seal (13).

5. Device according to claim 2, 3 or 4, wherein the annular lip seal (13) has in its edge region (14) a bend (15) which is directed away from the pressure-sensitive measuring element (3).

6. Device according to one or more of the preceding claims, wherein the upbent portion (15) of the annular lip seal (13) has a taper (16) towards the outer edge.

7. Device according to one or more of the preceding claims, wherein the pressure-sensitive measuring membrane (3) is a ceramic measuring membrane.

8. Device according to one or more of the preceding claims, wherein the nozzle (5) and the cup-shaped holder (11) are designed such that the pressure-sensitive measuring membrane (3) of the pressure sensor (2) in the mounted state contacts the flexible membrane (10) substantially without force transmission.

9. Device according to one or more of claims 1-7, wherein the nozzle (5) and the pot-shaped holder (11) are designed such that the pressure-sensitive measuring membrane (3) of the pressure sensor (2) has a maximum distance of 1 mm from the pressure-sensitive measuring membrane (3) in the mounted state.

10. Device according to one or more of the preceding claims, wherein the cup-shaped holder (11) and the nozzle (5) can be connected to one another via corresponding fastening elements (12a, 12b) on the cup-shaped holder (11) and the nozzle (5).

11. Device according to one or more of the preceding claims, wherein the tubular component (4) has connecting elements (6a, 6b) in both of its end regions.

12. Device according to one or more of the preceding claims, wherein the components (4, 5, 10, 11) of the disposable device (1) are made of a biocompatible material, for example polyethylene.

13. Device according to one or more of the preceding claims, wherein the pressure sensor (2) is a reusable pressure sensor (2).

14. Device according to one or more of the preceding claims, wherein the container (21) is a disposable container (21).

15. A method for manufacturing a device as described in at least one of claims 1-14, the flexible membrane (10) is attached to the radial stop edge (9) located on the inner surface (7) of the nozzle (5) of the tubular component (4), the modified tubular component (4, 10) is sealed in a bag and sterilized by means of radioactive radiation.

16. The method according to claim 15, wherein the flexible membrane (10) is attached to the radial stop edge (9) by a welding or gluing process.

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