WO2011048234A1

WO2011048234A1 - System for controlling sanitary products

Info

Publication number: WO2011048234A1
Application number: PCT/ES2010/000403
Authority: WO
Inventors: Esteban JANÉ RIBERA; Joan Xiol Foret
Original assignee: Alfos Solutions, S.L.
Priority date: 2009-10-07
Filing date: 2010-10-04
Publication date: 2011-04-28
Also published as: ES2367613B1; ES2367613A1; WO2011048234A8

Abstract

The system comprises at least one bag of a blood product, to which a laminar element comprising a passive UHF RFID tag is stuck, and at least one passive UHF RFID tag reading station.

Description

SYSTEM OF CONTROL OF SANITARY PRODUCTS

DESCRIPTION

The present invention refers to a control and traceability system for medical devices. More particularly, the present invention relates to an RFID identification system for bags of medical devices.

Currently, in blood banks, there are systems for monitoring and controlling bags of medical devices based on automatic identification systems, such as linear codes (bar codes) or two-dimensional codes (PDF codes or others). Both types of codes are printed on labels that adhere to one side of the bags of medical devices. These identification codes usually reflect information related to the extracted medical device, such as the date of donation, the expiration date of said medical device, laboratory tests and studies carried out or the transfusion center from which said donation proceeds, among other things. However, these automatic identification systems have some disadvantages, such as the small amount of data they can store, the need to have a direct view and a very short distance for reading the barcode or PDF between the barcode or PDF reader apparatus and the label containing said barcode or PDF, the inability to perform mass readings and high reading speeds or the inability to be reprogrammed, among other things. With the emergence of systems based on the emission of radiofrequency signals, such as automatic radio frequency or RFID identification technology, various embodiments related to the labeling of medicines for better management of them and avoid them have been disclosed forgeries, as with the labeling of staff of both the healthcare professional and the patients themselves.

The evolution of RFID technology has allowed in recent years it has been possible to conduct studies and pilot tests of control systems for bags of medical devices using RFID HF technology. This RFID HF tag technology works in High Frequency, of the English "High Frequency" (HF), which corresponds to a working frequency of 13.56 MHz. These RFID HF tags are passive, that is, they do not need to incorporate a battery in the tag, because they get the power they need to function from the field generated by the interrogator or reader of said RFID HF tags. The process of reading and writing these RFID HF tags by an RFID HF tag reader is based on the principle of inductive propagation, in which an inductive magnetic coupling of energy occurs between said RFID HF tag reader and said tags RFID HF. This phenomenon is possible because the antennas of the RFID HF tag and the RFID HF tag reader respectively communicate with each other by the magnetic component (or magnetic field) of the electromagnetic wave. This type of communication by magnetic field between antennas is also called Near Field communication or in English "Near Field" (NF). The great The advantage of this RFF HF technology is that the magnetic component is little altered by the presence of liquids or metals, which, a priori, is appropriate for working in such environments. An example of application of this type of technology is disclosed in EP 1850289 Al for an automated identification system for blood bags used in the work process of blood donation centers and medical institutions. This system uses passive type RFID tags at a working frequency of 13.56 MHz.

However, this RFID HF technology does not allow label readings over long distances (at most 0.5 meters) limiting its use in control systems with massive quantities of bags of medical devices. Generally, the size of the RFF HF antennas, which is considerable with respect to the size of the bag, and the arrangement of such labels in the central part of one of the sides of the bag, in many cases leads to reading errors by interference with liquids. In addition, a system implemented with this technology implies high costs for RFID HF tags and very high costs for RFID HF readers mainly due to its laborious manufacturing process. An example of the application of this type of RFID HF technology in sanitary products bags is explained in the F. Bidet document entitled "RFID Experience of a blood bag manufacturer", Bracknell, 12th March 2008, which describes a control system and of traceability of medical devices using RFID HF tags. However, it can be seen how in this case the RFID HF tag requires a large turn to obtain a range operational, although short. The large size of the loop does not completely prevent interference caused by the liquids in the bag. Additionally, the size of the tag causes the appearance of RDIF HF tag errors due to the appearance of defects in the RFID HF tags during bag manipulation (centrifugation, folding, etc.)

Due to this drawback, a method of applying an RFID tag to a medical device bag, in which said RFID tag is arranged perpendicularly to one of the faces of said bag, has been disclosed through document JP2006277524 (A) of sanitary product. Said RFID tag is positioned so that there is a slight separation between the elements that are part of the antenna of said RFID tag and the medical device bag. Such placement prevents contact between the RFID tag and the medical device bag preventing the absorption of electromagnetic waves from the radio frequency signal by the liquid content of said medical device bag. However, this method of applying RFID tags is not efficient for control applications in blood banks, where bags of medical devices are usually stored with only one another in the same compartment, because the contact between RFID tags of Different bags of medical devices could void the proper functioning of such RFID tags.

There is another type of RFID tags that work at Ultra High Frequency (frequency range between 840 and 960 MHz), in English "Ultra High Frequency" (UHF). Formerly this type of UHF RFID tags was based on the concept of Far Field or FF communication in English, that is, in the use of the electrical component (or electric field) of the electromagnetic wave for communication between the RFID UHF tag and the tag reader RFID UHF. This type of RFID UHF FF tags (in English "Far-Field UHF RFID") perfectly solves the different cases of labeling at the box and pallet level. However, because the electric field of an electromagnetic wave tends to be absorbed by liquids, the current state of the art considers that RFID UHF FF technology is not a suitable technique for use in the pharmaceutical sector and especially for systems of control of bags of sanitary products.

An example of this type of control system is WO 037026724, which discloses a system and method of identification of bags of medical devices in which a button-type RFID chip is incorporated in the bottom seam of the bag. Said RFID chip has a circular morphology and is small enough to be incorporated into said seam of the bag. However, this type of RFID chip, being too small in size, does not allow readings at far distances necessary for stock control. In the case of an RFF HF chip, the HF frequency range would not allow readings at far distances and, in the case of an RFID UHF chip, the antenna would be so inefficient that it would only allow readings at short distances. In either case, it does not allow a distant reading in batch or its placement allows an operational search in a bag storage. With the aim of overcoming the aforementioned problems, the present invention discloses a control system for bags of medical devices comprising at least one bag of a medical device having a passive type RFID tag and at least one reading station for RFID tags characterized in that said tag is a passive type UHF RFID tag, which comprises a Near Field communication element and another Far Field communication element. In this way, by using a UHF RFID tag capable of establishing communications by magnetic field and electric field, an optimal and improved system capable of establishing communications for any type of environment is achieved by improving the cost and scope of RFID tags and readers UHF

Said passive type UHF RFID tag comprises a central part in the form of a spiral as a Near Field communication element, an integrated circuit connected to said spiral and a dipole as a Far Field communication element formed by two elongated conductive elements located on both sides of said turn. This type of specific design of the UHF RFID tag allows it to work in both Near Field (magnetic field) and Far Field (electric field). Said design also allows its dimensions to be reduced and its shape to be elongated, allowing at the same time its efficient and optimized placement in the medical device bag in order to minimize contact or interference with the liquids contained within said medical product bag. . Preferably, said UHF RFID tag is attached to a laminar element which in turn is attached to said bag of medical device. More preferably, said passive-type UHF RFID tag is placed at the top, closest to the entrance duct of said bag, of the inner face of said laminar element and in perpendicular arrangement to the direction of said entry duct of said bag of a medical device. This preferred placement of the UHF RFID tag makes it possible to considerably minimize the possible contact of the UHF RFID tag with the liquids contained in the bag, thus minimizing possible interference of the radio frequency signal between the tag and the reader.

Preferably, said laminar element has a self-adhesive face, which contains said UHF RFID tag attached to a top part, which joins said bag of medical devices and an opposite face to said self-adhesive face that contains at least one automated visual code. Even more preferably, said face containing at least one automated visual code has at least one self-adhesive laminar element attached thereon containing at least one automated visual code.

In another preferred embodiment of the invention, the passive type UHF RFID tag is inserted in the perimeter seam of said medical device bag. Preferably, said RFID UHF tag is inserted in a side seam parallel to the inlet direction of the inlet duct of said bag, in vertical arrangement parallel to said inlet duct.

Preferably, a passive-type UHF RFID tag reader station comprises at least two UHF RFID antennas arranged between them so that each forms an angle between 45 and 90 degrees with another.

More preferably, said UHF RFID antennas are arranged forming an angle between 80 and 85 degrees.

Preferably, said UHF RFID tag reading antennas are configured so that one antenna acts as a transmitter while the other acts as a receiver.

Preferably, said passive type UHF RFID tag reading antennas are circular polarization antennas.

In a possible preferred embodiment, a reading station of said UHF RFID tags comprises a plurality of UHF RFID tag reading antennas, of which half are arranged at the top of a chamber access door and the other half are arranged in the side part closest to the lock of said access door to a camera.

In a possible preferred embodiment, a first antenna of said plurality of UHF RFID tag reading antennas acts as a transmitter and the remaining antennas as a receiver for a certain period of time.

Preferably, the reading station alternates the antenna that acts as a transmitter between the plurality of antennas over time.

Preferably, said UHF RFID tag reader station is in contact or in a very close arrangement with said UHF RFID tag and emits a radio frequency signal strength at least 1/4 of the maximum. In this way, it manages to avoid heating the medical device bag together with a timer that turns off the readers when not in use. An example of this embodiment is found at the time of updating data of a UHF RFID tag attached to a blood bag, when the content of said blood bag is modified or transformed. Another example of realization is at the time of issuing blood bags.

Preferably, said UHF RFID tag reader station is in a distant arrangement in an access door to an installation and comprises a plurality of antennas that radiate in the form of a sweep, so that there is always a reading antenna acting as a transmitter for a given period. and the rest of the antennas simply act as receivers. In this way, communication between the label and the reader is achieved by Far Field. An application of this embodiment is at the time of making massive plasma bag readings (approximately 70 bags per box) in the management of the stock of plasma bags.

Preferably, the system comprises a mobile type UHF RFID tag reader station that incorporates a reception power intensity measurement system and a user acoustic warning device, which allows us to locate the sanitary product bags.

For better understanding, some drawings of a preferred embodiment of the present invention are attached by way of explanatory but not limitative example. Figure 1 shows a diagram of a laminar element containing a passive type UHF RFID tag belonging to a system according to the invention.

Figure 2 shows a diagram of a sanitary product bag presenting a laminar element attached to it of the type shown in Figure 1 belonging to a system according to the invention.

Figure 3 shows a diagram of a sanitary product bag of the type shown in Figure 2 containing a laminar element adhered thereto belonging to a system according to the invention.

Figure 4 shows a diagram of a sanitary product bag presenting a passive type UHF RFID tag inserted in a side seam of said bag.

Figure 5 shows different elements of a system according to the present invention.

Figure 1 shows a preferred embodiment of an RFID tag UHF -2- according to the present invention. Said RFID tag UHF -2- has an elongated rectangular shape and reduced dimensions so that it can be placed both on the upper part of the inner face -11- of a laminar element -1- and on the seam -8- of the edge of a bag -3- of medical device (figure 4). The placement of the RFID tag UHF -2- on the upper part of the inner face -11- of said laminar element -1-, as shown in Figure 1, has been carried out so that when placing said laminar element - 1- in a sanitary product bag -3- as in Figure 2, said RFID tag UHF -2- is arranged perpendicularly and as close as possible to - Il ^¬ the inlet direction of the inlet duct of said medical device bag -3-.

A preferred embodiment of said RFID tag UHF -2- comprises a central part in the form of a turn -22-, an integrated circuit -21- connected to said turn -22- and a dipole formed by two elements -23-, -24- elongated conductors located on both sides of said loop -22-.

The loop -22- is the element responsible for generating an electric current in said RFID tag UHF -2- in the event that there is a flux variation of a magnetic field in the time close to said loop -22-. Said electric current is used to feed said RFID tag UHF -2- in order to perform data read or write operations in the memory of the integrated circuit -21-. This type of magnetic field communication, also called Near Field communication, is only achievable if the distance between the reader (-5-, -6-, -71- and -72-) of RFID tags

2D ² UHF -2- and said RFID tag UHF -2- is less than —— ·,

TO

where D is the maximum antenna dimension and λ is the wavelength of the radio frequency signal. Within this range, it is possible to ensure optimal and effective communication in extreme cases such as in the presence of liquids. Given the characteristics of the HF (13.56 MHz) and UHF (between 840 and 960 MHz) technologies respectively, to achieve the same range in both technologies, the dimensions of the HF loop must be approximately of an order of magnitude greater than the dimensions of the UHF loop. This implies obtaining UHF RFID tags with an area approximately two orders of magnitude smaller than RFF HF tags. Additionally, in the manufacturing process of the UHF loop it is only necessary to perform one step instead of the 4 steps necessary for the HF turn, so the manufacturing cost of the UHF turn is three or four times less than that of a HF exhale.

The dipole formed by two elements -23-, -24- elongated conductors is the element responsible for generating an electric current in said RFID tag UHF -2- in the case of receiving an electric field. Said electric current is also used to feed said RFID tag UHF -2- in order to perform data read or write operations in the memory of the integrated circuit -21-. This type of communication by electric field, also called Far Field communication, is only possible if the distance between the reader (-5-, -6-, -71- and -72-) of RFID tags

2D ²

UHF -2- and said RFID tag UHF -2- is greater than,

TO

where D is the maximum antenna dimension and A is the wavelength of the radio frequency signal. This range radius allows optimal and effective communication over long distances compared to RFID HF technology.

The integrated circuit -21- is the element responsible for managing the reading and writing of data by the reader (-5-, -6-, -71- and -72-) of RFID tags UHF -2-, once this The elements of said RFID UHD -2- tag have been communicated by magnetic field or by electric field.

Figure 2 shows a first preferred embodiment of a bag -3- of medical device in the which adheres on one of its faces a laminar element -1-. Said laminar element -1- adheres to said pouch -3- of medical device on the self-adhesive side -11- comprising said RFID tag UHF -2-, so that said RFID tag UHF -2- is arranged perpendicularly and as much as close as possible to the inlet direction of the inlet duct of said medical device bag -3-. The opposite side -12- to the internal self-adhesive face -11- comprising said RFID tag UHF -2- comprises at least one automated visual code -13-, such as for example a linear bar code (bar codes), a two-dimensional code (PDF or other codes), a matrix code, etc. You can also use, for example, a set of codes according to the American standard ISBT128 comprising 4 barcodes. These automated visual codes -13- can serve, for example, to identify blood bags in blood banks and control information such as blood type or donor's name among other things. In any case, said RFID tag UHF -2- comprises the same digitized information as in said automated visual codes -13-, trying to increase the existing functionalities.

Figure 3 shows a first preferred embodiment of a bag -3- of medical device such as that shown in Figure 2 in which at least one laminar element -4- adheres at least one laminar element -4- containing at least one code automated visual -43-, such as a linear bar code (bar codes), a two-dimensional code (PDF or other codes), a matrix code, etc. In this first embodiment, the content of the bag -3- through a new laminar element -4- which includes the information contained in the medical device bag at this time. In parallel, said RFID tag UHF -2- is able to update the information of the new medical device of the bag -3- maintaining at all times an exhaustive control of the medical device that comprises the bag -3-.

Figure 4 shows a second preferred embodiment of a sanitary product bag -3- in which the passive-type RFID tag UHF -2- is inserted into a side seam -8- of said bag -3- in an arrangement parallel to the inlet duct of said bag -3-. The insertion of the RFID tag UHF -2- into one of the side seams -8- of the bag -3- is carried out, for example, during the process of sealing the sheets that make up the bag -3-. According to this second embodiment, the sanitary product bag -3- also comprises a laminar element -1- adhered to one of the faces of the sanitary product bag -3-. Said laminar element -1- also comprises at least one automated visual code -13-, such as for example a linear bar code (bar codes) or a two-dimensional code, among others, with the information of the medical device it contains the bag -3-. In this case too, the RFID tag UHF -2- inserted in one of the seams of the bag -3- comprises the same digitized information as in said automated visual codes -13-, trying to increase the existing functionalities. According to this second embodiment, in order to update the contents of the bag -3- due to the content of a new medical device, a new laminar element (not shown) is added which comprises the information of the new Sanitary product and in parallel, the information of the new sanitary product of the bag -3- is updated in said RFID tag UHF -2-, maintaining at all times an exhaustive control of the sanitary product comprising the bag -3-.

Figure 5 shows a sanitary product bag -3-, a mobile reading station -5- of RFID UHF tags and a fixed reading station -6- composed of two reading antennas -61-, -62- of RFID UHF tags. Additionally, Figure 5 shows a preferred embodiment of a typical location of a fixed RFID UHF tag reader station, comprising 4 reading antennas -71-, -72-, -73-, -74-.

The medical product bag -3- of Figure 5 is of the type shown in Figure 2 and comprises a laminar element -1- adhered thereto. Said laminar element -1- comprises on its internal self-adhesive face -11- an RFID tag UHF -2- so that said RFID tag UHF -2- is arranged perpendicularly and as close as possible to the direction of the entrance duct of said bag of medical device -3-. Said RFID tag UHF -2- is of the type shown in Figure 1 and therefore allows communications both by Near Field and Far Field. This spatial arrangement of the -2-RFID UHF label in said medical product bag -3- allows to avoid interference caused by the liquids contained in sanitary product bags, such as red blood cell bags. This type of sanitary product bags are usually stored in an upright position inside a transport box. This vertical storage arrangement causes the liquid contained in said bags to precipitate from the highest part of the bag, where the -2- RFID UHF tag is located, to the lowest part of said bag. The elongated typology of the UHF RFID tags object of the present invention allows a horizontal arrangement thereof to avoid interference with the liquid. Thus, placing said labels -2- RFID UHD in the highest part and closest to the inlet duct of said bags -3- of medical devices allows eliminating a possible direct interference between the liquid of said bags -3- and said tags -2- RFID UHF. The mobile reader station -5- of RFID UHF tags allows to communicate with a RFID tag UHF -2- by Far Field, that is, by the electrical component of the electromagnetic wave. For this, said mobile reader station -5- emits at the maximum power intensity (200mW) so that the radio frequency signal can be received by said RFID tag UHF -2-, due to the distance between the mobile reader station -5 - and said RFID tag UHF -2-. Said RFID tag UHF -2-, being able to communicate both by Near Field and Far Field, will be able to maintain a communication by Far Field with said mobile reading station -5- thanks to the dipole formed by two elements -23-, -24 - elongated conductors of said RFID tag UHF -2-.

An important variable when establishing optimal and efficient communication between said RFID UHF -2 tags and a reading station of said RFID UHF tags is the choice of the type of polarization that the interrogation antenna has to have. The polarization of an antenna refers to the way in which the radio frequency electromagnetic wave is transmitted. There are 3 types of polarization: linear, circular and elliptical. The RFID tags UHF -2- are linearly polarized so that the electric field component of the radio frequency signal propagates in a single plane. A disadvantage when choosing a reading station with linearly polarized antennas is that both elements (reading station and UHF RFID tag) must be arranged coplanarly to achieve optimal communication. This is usually very complicated and implies a very accurate reading process because the bags of medical devices must all be oriented in a specific way in order to be read. In order to solve this problem, it is advantageous that the interrogation antennas of the reading station are circularly polarized. That is, the electric field component of the electromagnetic signal rotates (clockwise or counterclockwise) while propagating away from the interrogation antenna of the reading station. A clear advantage of this type of polarization is that the orientation of the RFID tag is no longer important for the interrogation antenna and this is capable of establishing optimal communication with said RFID UHF tag. Thus the mobile reader station -5- is circularly polarized.

Additionally, said mobile reading station -5- of RFID UHF tags incorporates a reception power intensity measurement system to be able to know at all times what power intensity said reading station is transmitting to one or several bags of sanitary products and the intensity received by RFID UHF -2- tags, being able to calculate how far and where the bags are. In addition, said Mobile reader station -5- of RFID tags UHF comprises a warning device, such as an acoustic device for example, to indicate to the user the proximity of a medical device bag according to the measurement of the transmission power intensity. This allows to locate specific blood bags within a mass storage.

In one embodiment, the fixed reading station -6- is composed of two reading antennas -61-, -62- of RFID tags UHF -2- arranged at a 90 degree angle between them. This arrangement allows said fixed reading station -6- to efficiently use the range of the electromagnetic signal when transmitting or receiving a radio frequency signal. The reading antennas -61-, -62- of RFID tags UHF -2- are configured so that one antenna acts as a transmitter, that is, it emits an electromagnetic signal to activate the RFID tag UHF -2-, while the other antenna It acts as a receiver receiving any possible response of said RFID UHF -2- tag, said fixed reading station -6- allows to communicate with an RFID UHF -2- tag both by Far Field, that is to say by the electrical component of the electromagnetic wave, as by Near Field by the magnetic component of the electromagnetic wave.

In the case of a communication by Far Field, said RFID tag UHF -2-, being able to communicate both by Near Field and Far Field, you can maintain a communication by Far Field with said fixed reading station -6- thanks to the dipole formed by two elements -23-, -24- elongated conductors of said RFID tag UHF -2-. In the case of a Near Field communication, that is to say through the magnetic component of the electromagnetic wave, said RFID tag ÜHF -2-, being able to communicate both by Near Field and Far Field, you can maintain a communication with said station fixed reader -6- by Near Field thanks to the turn -22- of said RFID tag ÜHF -2-, which is the element capable of receiving said magnetic component of the electromagnetic wave. An example of application of this embodiment is at the time of labeling a blood bag for the first time. In this case, the radiation power level of the reading antennas must be at least 1/4 of the maximum (in this case the maximum is of the antenna is 1.6 W) which is equivalent to having an attenuation of 6 dB of the maximum radiation power level, to prevent the radiation of the radiofrequency wave from raising the temperature of the liquid contents of the bags. Additionally, to avoid heating the bags during their reading process, sensors are used to know at all times if said reading station is in operation or not, limiting the time of use of said reading station. In the case of blood bag monitoring, the use of said RFID tag UHF -2- in both the Near and Far Field allows us to monitor different products of different controlled temperatures.

Another example of radiation application that combines a Near Field communication and a Far Field communication is at the moment of updating (when the content of said blood bag is modified or transformed) of data from a UHF RFID tag attached to a blood bag. In this case the antenna layout is the same and the radiation power levels too. Even so, because there is more than one bag on top of the L-structure and that these bags can be on top of each other, it is necessary to use both magnetic and electrical coupling communication (by Near Field and Far Field respectively ) to activate RFID tags UHF -2-.

Finally, for the communication between said RFID tags UHF -2- and said reading station -6- to be carried out in an optimal and efficient way, - said fixed reading station -6- of RFID tags UHF -2- must be circularly polarized Thus, the orientation of the RFID tag is no longer important for the interrogation antenna and it is able to establish optimal communication with said RFID UHF tag, achieving optimal and efficient communication regardless of the orientation of the RFID UHF tag.

Figure 5, finally, shows a preferred embodiment of a typical location of a fixed reading station composed of four reading antennas (-71-, -72-, -73-, -74-) of RFID tags UHF -2-, of which two (-71-, -72-) are arranged in the upper part of an access door to a chamber and two (-73-, -74-) are arranged in the lateral part closest to the lock of said access door to a camera.

Said fixed reading antennas -71-, -72-, -73-, -74- are capable of establishing a communication with RFID UHF -2- tags by Far Field, that is to say by the electrical component of the wave electromagnetic In this case, the radiation of the antennas is carried out in the form of a sweep, so that there is always a reading antenna acting as a transmitter at a given time, while the rest of the antennas simply act as receivers. At the beginning of the scanning sequence, the antenna -71- acts as a transmitter by emitting a radio frequency signal for a time interval ti while the rest of the antennas (-72-, -73-, -74-) simply act as receiving At the end of said time interval ti, the antenna -71- that was emitting happens to listen together with the antennas -73- and -74- and the antenna -72- begins to emit during a second time interval t ₂ . At the end of said time interval t ₂ , the antenna -72- that acted as a transmitter becomes the receiver together with the antennas -71- and -74- and the antenna -73- begins to emit during a third time interval t ₃ . At the end of said time interval t ₃ , the antenna -73- that acted as the transmitter becomes the receiver together with the antennas -71- and -72- and the antenna -74- begins to emit during a fourth time interval t ₄ . At the end of said fourth time interval t ₄ , the scanning sequence starts again, so the antenna -74- that acted as the transmitter becomes the receiver together with the antennas -72- and -73- and the antenna -71 - reissues for a period of time you.

This arrangement allows, for example, to control the plasma stock stored in the plasmateca. It is a feature in blood banks that does not exist to date and is very useful for managing the massive amounts of plasma stored. Being arranged in this way, the fixed reading antennas -71-, -72-, -73-, -74- allow to read large quantities of plasma bags and thus be able to manage the real stock of bags at any time, controlling the time that the bags are outside and inside the refrigerated chamber between many other things. Likewise, such an arrangement of two antennas above the door and two antennas next to the door allow to read large quantities of plasma bags arranged in transport carts with two floors.

The level of radiation power emitted by the reading antennas (-71-, -72-, -73-, -74-) depends on the state of the plasmateca access door thanks to a sensor that lets you know if The door is closed or if it is otherwise open. If the sensor indicates that the plasmateca door is closed, then the antennas radiate in the form of a sweep, as explained above, at maximum power (1.6 W), that is, with an attenuation of 0 dB for each antenna. If, on the contrary, the sensor indicates that the door is open, then these antennas continue to radiate in the form of a sweep but with different attenuations depending on the antenna. The upper left antenna (-71-) radiates with an attenuation of 7 dB, the upper right antenna radiates with an attenuation of 6 dB, the upper lateral antenna radiates with an attenuation of 4 dB and the lower lateral antenna radiates with an attenuation of 3 dB With this configuration it is possible to avoid the signal bounces towards the interior of the chamber because the metal door of access to the plasmatheque acts like a mirror, reflecting a large amount of waves towards the interior of the chamber.

While the invention has been described with respect to a preferred embodiment, they should not be consider limiting of the invention, which will be defined by the broader interpretation of the following claims.

Claims

1. Control system for bags of medical devices comprising at least one bag of a medical device having a passive type RFID tag and a passive type RFID tag reader station characterized in that said tag is a passive type UHF RFID tag comprising a central part in the form of a spiral, an integrated circuit connected to said spiral and a dipole formed by two elongated conductive elements located on both sides of said spiral.

2. System according to claim 1, characterized in that said UHF RFID tag is attached to a laminar element which in turn is attached to said pouch of medical device.

3. System according to claim 2, characterized in that said passive-type UHF RFID tag is placed on the upper part, closer to the entrance duct of said bag, of the inner face of said laminar element and arranged perpendicular to the direction of inlet of said inlet duct of said bag.

System according to claim 3, characterized in that said laminar element has a self-adhesive face that joins said bag of medical devices and an opposite face that contains at least one automated visual code.

System according to claim 4, characterized in that said adhesive face contains a passive type UHF RFID tag adhered on a top.

6. System according to claim 4, characterized in that said face containing at least one Automated visual code has at least one self-adhesive laminar element attached to it containing at least one automated visual code.

System according to claim 1, characterized in that said passive type UHF RFID tag is inserted in the perimeter seam of said bag.

System according to claim 7, characterized in that said passive type UHF RFID tag is inserted in a side seam parallel to the inlet direction of the inlet duct of said bag, in vertical arrangement parallel to said inlet duct.

System according to claim 1, characterized in that a passive-type UHF RFID tag reader station comprises at least two UHF RFID antennas arranged at an angle between 45 and 90 degrees.

System according to claim 9, characterized in that said UHF RFID antennas are arranged forming an angle between 80 and 85 degrees.

A system according to claim 9, characterized in that said UHF RFID tag reading antennas are configured so that one antenna acts as a transmitter while the other acts as a receiver.

12. System according to claim 9, characterized in that a passive-type UHF RFID tag reader station comprises a plurality of UHF RFID tag reader antennas, of which half are arranged at the top of a door of access to a camera and the other half are arranged on the side closest to the lock of said access door to a camera.

13. System according to claim 11, characterized in that during a certain period of time a first antenna of said plurality of RFID UHF tag reading antennas acts as a transmitter and the rest of the antennas as a receiver.

14. System according to claim 11 to 12, characterized in that the reading station alternates the antenna that acts as a transmitter between the plurality of antennas over time.

15. System according to claim 1, characterized in that a passive type UHF RFID tag reader station is of the mobile type and incorporates a reception power intensity measurement system and an acoustic device.

16. System according to claim 1, characterized in that said passive type UHF RFID tag reading antennas are circular polarization antennas.