METHOD FOR MONITORING THE SEALING OF A CONTAINER AND DEVICE WITH IMPROVED SEALING MONITORING

Abstract

A method for monitoring the sealing of a container in a system or device is described. The method includes the following steps: controlling the heating element to heat a heating stamp to a predetermined sealing temperature, monitoring the temperature of the heating stamp, determining a temperature over time curve of the heating stamp by means of at least one temperature sensor, determining at least one characteristic of the temperature over time curve, comparing the determined at least one characteristic of the temperature over time curve with a reference value, and determining a sealing property of the sealing of the container based on said comparison of the determined at least one characteristic of the temperature over time curve with the reference value.

Claims

1. A method for monitoring the sealing of a container in a laboratory system or device, the system or device comprising: a holder for receiving a container to be sealed, a heating stamp with a heating surface and a heating element for heating of the heating stamp and of the heating surface, wherein the holder and the heating stamp are movably arranged relative to each other between a loading position and a sealing position, wherein in the sealing position the heating stamp is arranged closer to the holder than in the loading position and the heating surface of the heating stamp is in contact with a foil arranged on an opening of the container, at least one temperature sensor for monitoring a temperature of the heating stamp, and a control unit connected at least to the heating element and the temperature sensor; the method comprising the following steps: the control unit controlling the heating element to heat the heating stamp to a predetermined sealing temperature, monitoring the temperature of the heating stamp and determining a temperature over time curve of the heating stamp by means of the at least one temperature sensor, moving the holder and/or the heating stamp from the loading position to the sealing position, after a predetermined amount of time, moving the holder and/or the heating stamp (3) from the sealing position to the loading position, the control unit determining at least one characteristic of the temperature over time curve, the control unit comparing the determined at least one characteristic of the temperature over time curve with a reference value, and the control unit determining a sealing property of the sealing of the container based on said comparison of the determined at least one characteristic of the temperature over time curve with the reference value.

2. The method according to claim 1, wherein the characteristic of the temperature over time curve is the course of the temperature over time curve and the reference value is a reference temperature over time curve.

3. The method according to claim 1, wherein the characteristic of the temperature over time curve is an integral of the temperature over time curve and the reference value is a reference integral value.

4. The method according to claim 1, wherein the system or device comprises an actuator for moving the holder and/or the heating stamp between the loading position and the sealing position and the control unit is connected to the actuator and controls the actuator for moving the holder and/or the heating stamp.

5. The method according to claim 1, wherein the at least one characteristic of the temperature over time curve is determined for a time interval, the time interval corresponding to the time where the holder and the heating stamp are in the sealing position.

6. The method according to claim 1, wherein the system or device comprises at least one force sensor for measuring a force applied to the holder and/or the heating stamp when in the sealing position and the control unit is connected to the force sensor and determines a force applied to the holder and/or the heating stamp.

7. The method according to claim 6, wherein the method further comprises the following steps: the control unit monitoring the force applied to the holder and/or the heating stamp, the control unit determining if sufficient force has been applied to the holder and/or the heating stamp.

8. A system or device, in particular a laboratory system or device, comprising: a holder for receiving a container to be sealed; an heating stamp with a heating surface and a heating element for heating of the heating stamp and of the heating surface, wherein the holder and the heating stamp are movably arranged relative to each other between a loading position and a sealing position, wherein in the sealing position the heating stamp is arranged closer to the holder than in the loading position and the heating surface of the heating stamp is in contact with a foil arranged on an opening of the container; at least one temperature sensor for monitoring a temperature of the heating stamp; and a control unit connected at least to the heating element and the temperature sensor; wherein the control unit is configured to: control the heating element to heat the heating stamp to a predetermined sealing temperature, monitor the temperature of the heating stamp and determine a temperature over time curve of the heating stamp by means of the at least one temperature sensor; determine at least one characteristic of the temperature over time curve; compare the determined at least one characteristic of the temperature over time curve with a reference value; determine a sealing property of the sealing of the container based on said comparison of the determined at least one characteristic of the temperature over time curve with the reference value, at least between: a movement of the holder and/or the heating stamp from the loading position to the sealing position, and a movement of the holder and/or the heating stamp from the sealing position back to the loading position after a predetermined amount of time.

9. The system or device according to claim 8, wherein the characteristic of the temperature over time curve is the course of the temperature over time curve and the reference value is a reference temperature over time curve.

10. The system or device according to claim 8, wherein the characteristic of the temperature over time curve is an integral of the temperature over time curve and the reference value is a reference integral value.

11. The system or device according to claim 8, further comprising an actuator for moving the holder and/or the heating stamp between the loading position and the sealing position and the control unit is connected to the actuator and is configured to control the actuator for moving the holder and/or the heating stamp.

12. The system or device according to claim 8, wherein the at least one characteristic of the temperature over time curve is determined for a time interval, the time interval corresponding to the time where the holder and the heating stamp are in the sealing position.

13. The system or device according to claim 8, further comprising at least one force sensor for measuring a force applied to the holder and/or the heating stamp when in the sealing position and wherein the control unit is connected to the force sensor and is configured to determine a force applied to the holder and/or the heating stamp.

14. The system or device according to claim 13, wherein the control unit is further configured to: monitor the force applied to the holder and/or the heating stamp, and determine if sufficient force has been applied to the holder and/or the heating stamp.

15. A non-transitory computer-readable storage medium including program code, which when executed by at least one data processor, causes a system or device comprising: a holder for receiving a container to be sealed, a heating stamp with a heating surface and a heating element for heating of the heating stamp and of the heating surface, wherein the holder and the heating stamp are movably arranged relative to each other between a loading position and a sealing position, wherein in the sealing position the heating stamp is arranged closer to the holder than in the loading position and the heating surface of the heating stamp is in contact with a foil arranged on an opening of the container, at least one temperature sensor for monitoring a temperature of the heating stamp, and a control unit connected at least to the heating element and the temperature sensor; to perform operations comprising: controlling the heating element to heat the heating stamp to a predetermined sealing temperature, monitoring the temperature of the heating stamp and determining a temperature over time curve of the heating stamp by means of the at least one temperature sensor; determining at least one characteristic of the temperature over time curve; comparing the determined at least one characteristic of the temperature over time curve with a reference value; and determining a sealing property of the sealing of the container based on said comparison of the determined at least one characteristic of the temperature over time curve with the reference value.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 shows a schematic sectional view of a device according to the present invention, and

[0043] FIGS. 2A-F show examples of temperature over time curves.

DETAILED DESCRIPTION

[0044] The invention will be described now by way of a preferred embodiment in connection with the drawings.

[0045] As used herein, the terms have, comprise or include or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions A has B, A comprises B and A includes B may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.

[0046] Further, it shall be noted that the terms at least one, one or more or similar expressions indicating that a feature or element may be present once or more than once typically will be used only once when introducing the respective feature or element. In the following, in most cases, when referring to the respective feature or element, the expressions at least one or one or more will not be repeated, non-withstanding the fact that the respective feature or element may be present once or more than once.

[0047] Further, as used herein, the terms preferably, more preferably, particularly, more particularly, specifically, more specifically or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by in an embodiment of the invention or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.

[0048] In FIG. 1, a component of the laboratory system or device 1 according to the present invention is shown. From the bottom, a holder 2 for a container 8 is shown schematically, wherein the opening 7 of the container 8 is suggested by the arrow. Above the opening 7 of the container 8 there is arranged a sealing foil for sealing the opening 7 of the container.

[0049] Above the holder 2, a heating stamp 3 is arranged. The heating stamp 3 comprises a heating surface 4, two heating elements 5 and a force sensor 12. The heating stamp 3 and therefore the heating surface 4 is heated by controlling the heating elements 5 via the control unit 10.

[0050] The control unit 10 is also connected, symbolized by the dotted line, to an actuator 11 for moving the heating stamp 3 along the Z axis between a loading position L and sealing position S, wherein in the sealing position S the heating surface 4 of the heating stamp 3 contacts the foil 6. Loading position L and sealing position S are shown by means of a dotted line corresponding to a plane of the heating surface 4 in the respective position.

[0051] In the example shown in FIG. 1, the actuator 11 comprises a motor 13 and a spindle 14, wherein rotation of the motor 13 and therefore of the spindle 14 causes the movement of the heating stamp 3 along the Z axis. The heating stamp 3 is provided with a threaded portion (not shown) engaging the spindle 14 for this purpose.

[0052] For sealing the container 8, the heating stamp 3 is controlled by the control unit 10 and heated to a predetermined temperature. After the predetermined temperature has been reached, the heating stamp 3 is lowered by the actuator 11 from the loading position L to the sealing position S, wherein the heating surface 4 contacts the foil 6, therefore sealing the container opening 7 with the foil, as explained above. The heating stamp 3 is pressed against the holder 2 with a predetermined force, which is monitored and controlled by the control unit by means of the force sensor 12, and may be used in a preferred example for determining that the heating stamp 3 has reached the sealing position S.

[0053] During the sealing process, when the heating stamp 3 is in the sealing position, the control unit monitors the temperature of the heating stamp 3 by means of the temperature sensors 9 and determines a temperature over time curve (TT) of the heating stamp. Different TT curves are shown schematically in FIGS. 2A-F. After a predetermined amount of time, the heating stamp 3 is raised again to the loading position L, thus terminating the sealing process.

[0054] The control unit then determines, based on a characteristic of the determined TT curve and comparison with a reference value, if the sealing process was successful performed or not.

[0055] Alternatively, the control unit determines in real time, based on a characteristic of the determined TT curve and comparison with a reference value, that the sealing process has been performed successfully and therefore controls the actuator 11 to raise the heating stamp 3 to the loading position, therefore terminating the sealing process. In addition, the control unit may be configured to raise the heating stamp 3 after a predetermined amount of time if the real time determination of the termination of the sealing process is not successful.

[0056] FIG. 2A shows a TT curve for a successful sealing process determined via one of the temperature sensors 9. At the time t1, the heating stamp 3 contacts the foil 6, and therefore, the temperature drops. However, the control unit controls the heating stamp 3 to keep the predetermined temperature, and the temperature raises again. At time t2, the heating stamp 3 is moved from the sealing position S to the loading position L, therefore terminating the sealing process. Determination of the success of the sealing process is made by the control unit by comparing the determined TT curve with a reference value. The reference value may be a reference TT curve, wherein the control unit 10 determines if the TT curve lies within a predetermined tolerance range from the reference TT curve. Alternatively or additionally, the integral of the TT curve, the surface below the TT curve, may be compared with a reference integral value of a reference TT curve. Preferably, the determination is only done for the period of time from t1 until t2. For sake of simplicity, the TT curve of FIG. 2A is taken as a reference when comparing the following TT curves shown in FIGS. 2B-D.

[0057] FIG. 2B shows a TT curve for an unsuccessful sealing process determined via one of the temperature sensors 9. As can be seen, the TT curve is a straight horizontal line, meaning that there was no thermal contact between the heating stamp 3 and the foil 6.

[0058] FIG. 2C shows another TT curve for an unsuccessful sealing process determined via one of the temperature sensors 9. As can be seen, the TT curve shows only a minor decrease of temperature between the time t1 and t2, meaning that there was no sufficient heat transfer from the heat stamp 3 to the foil 6 for a sufficient sealing. This determination is done by comparing the TT curve and/or the integral of the TT curve, preferably from t1 to t2, with a reference value, as shown in FIG. 2A.

[0059] FIG. 2D shows another TT curve for an unsuccessful sealing process determined via one of the temperature sensors 9. As can be seen, the TT curve shows a higher decrease of temperature between the time t1 and t2 as compared to the TT curve shown in FIG. 2A, meaning that there was an anomaly in the heat transfer from the heat stamp 3 to the foil 6, which can mean that here was a thermal short circuit between the heat stamp 3 and the holder 2, e.g. because the foil 6 was missing. This determination is done by comparing the TT curve and/or the integral of the TT curve, preferably from t1 to t2, with a reference value, as shown in FIG. 2A.

[0060] FIG. 2E shows two TT curves for a successful sealing process determined via both of the temperature sensors 9, The TT line 1 is shown as a plain line, while the TT line 2 is shown as a dotted line. As can be seen in FIG. 2E, both curves TT1 and TT2 are almost identical, therefore representing a successful sealing process. At the contrary, FIG. 2F shows two TT curves TT1 (plain) and TT2 (dotted) where the course of the curve TT1 corresponds to the one of FIG. 2A, while the course of the curve TT2 corresponds to the TT curve of FIG. 2B. In this case, the control unit 10 determines that at least for one temperature sensor 9, the determined characteristic of the TT curve does not correspond to a reference value and therefore the sealing process is considered as not successful.