Protective cap

IS 2 200 149 T3

DESCRIPTION

Protective cap.

The present invention relates to a protective cap for an infrared radiation thermometer according to the generic term of claim 1.

Infrared radiation thermometers are used to measure body temperature. Such a radiation thermometer usually has a housing with a window for radiation entry, an internal optical device, and an infrared sensor attached to an analyzer unit. The radiation inlet window serves to close the inside of the radiation thermometer housing, thereby protecting the optics and sensor from dirt and possible destruction.

As additional protection, protective caps of the type mentioned at the beginning are placed on the end of the thermometer; these protective caps are described, for example, in EP-B1-0 201 790, US-A-5,179,936 or US-A5,293,862. These protective caps serve not only to protect the window that lets infrared radiation pass, but also to protect the user from the possible transmission of diseases since, before carrying out a temperature measurement or a measurement - also in the case of different people - a new protective cap is fitted each time. The disposable “Spekulum”, a name given in documents EP-B1-0 201 790, US-A-5,179,936 or US-A-5,293,862 is pushed through the probe of the atrial canal of a sensitive middle ear thermometer to infrared radiation, said disposable Spekulum presenting a membrane permeable to infrared radiation, based on polypropylene or polyethylene. The part that carries the membrane is a die-cast part.

To determine a person's body temperature, the front end of the temperature-measuring probe is inserted into the ear. The infrared radiation emitted by the eardrum and the atrial canal enters the thermometer through the window and falls through the optical device or a light conductor and an interference filter on the infrared sensor. The increase in temperature produced in the sensor results in an electrical output voltage, from which, by means of an analyzer unit, the temperature of the radiation can be determined.

In this type of apparatus it has been found that, due to the contact of the ear with the coldest optics, in general, of the thermometer during the measurement, a temperature gradient is produced inside the optics of the thermometer, which usually produces an error of measure. Also, the atrial canal is cooled by the thermometer. Because the thermometer also records infrared radiation from the atrial canal or other body cavity into which the radiation thermometer is inserted, this creates a new source of measurement errors.

To avoid these measurement errors, EP 0 674 162 A2 describes a thermally insulated measuring tip, which has an outer shaft and a heat sink, between which is an insulating air gap. A protective cap can be attached to the measuring tip.

Starting from the state of the art indicated at the beginning and the consequent problems of the possible occurrence of measurement errors, the aim of the present invention is to create a protective cap, by means of which, on the one hand, the user is protected of this infrared thermometer for fever, against the transmission of diseases, and also protect the optics of the thermometer from dirt. On the other hand, it is necessary to avoid or at least substantially reduce the measurement errors that usually occur with the fever thermometers with protective cap, described above.

This problem is solved, in a protective cap of the type described at the beginning, according to a first invention, by the main features of claim 1. Precisely the area of ​​the base body, directly adjacent to the window and therefore in intimate contact with the wall of the body cavity, for example the atrial canal, is isolated in such a way by additional structures that the transmission of heat in This area to the infrared optics is reduced or kept so small that it can be neglected, since it does not affect the temperature measurement. Since, due to the thermal insulation of the protective cap, the passage of heat outside the window is reduced, the cooling of, for example, the atrial canal also decreases at the same time. The consequence of this is that, due to the less cooling of the ear, the user feels that the thermometer, with this protective cap, is warmer and therefore much more pleasant.

Furthermore, this heat insulating medium can have a soft configuration, which is more pleasant on the ear than a solid material, which does not yield or a protective cap coated with such a material. Another advantage of a protective cap of this kind can be appreciated especially when it is used, in conjunction with a fever thermometer, with a small measuring tip. A fever thermometer, with a small measuring tip, is suitable for measuring the temperature of adults as well as children, since this protective cap made of heat-insulating material is offered in at least two sizes. But such a protective cap can also be made of a particularly soft, thermally insulating and therefore ductile material, which can be used in the ear canal of adults as well as children, despite the difference in sizes. These protective caps according to the invention are used as single-use protective caps.

In order to allow easy, yet accurate placement of the protective cap in the atrial canal, and to also avoid various incidences of temperature due to differences in placement, at least the outer surface in contact with the atrial canal or The entire surface of the base body outside the window area should be provided with thermal insulating means. With such a configuration of the surface of the protective cap, sufficient thermal insulation is always guaranteed from the probe to measure the temperature, in the most diverse positions of the fever thermometer.

Another possibility of increasing the thermal insulation of the probe to measure the temperature of the radiation thermometer is that the entire base body, outside the window, is provided with thermal insulating means, that is, not only the outer face but also its face. inside. With a measure of this

ES 2 200 149 T3 type it is possible to achieve, on the one hand, that the thickness of the outer layer on the base body, based on thermal insulating means, is not too great and, on the other hand, the insulating means can be dimensioned thermal on the inner face and adjust its ductility in such a way as to achieve at the same time a support that maintains, albeit removably, the protective cap on the end of the radiation thermometer.

The base body can at the same time serve as a stable support for the thermal insulating material that is applied at least on the outside. As a heat insulating means of the additional structure, a soft porous plastic is preferably used.

With the features of claim 2, the thermal insulation effect is further enhanced. In the configuration of the protective cap in one or more air chambers, it is preferred to cover the outer face with a flexible outer foil. This outer foil at the same time constitutes a smooth outer surface, which offers little possibility for dirt to accumulate and deposit during storage of the protective caps.

Polypropylene (PP), polyvinyl or polyethylene (PE) are proposed as a flexible outer sheet, which limits, for example, the air chamber or the air chambers of a thermal insulating medium. The aforementioned materials are, on the one hand, cheap, and, on the other hand, they can be easily manufactured to manufacture the thermal insulating body and, finally, they are compatible with the skin, something essential for the field of application of thermometers to measure fever.

In the event that the additional structures of the thermal insulating means are constituted by several air chambers, it may be useful to subdivide them by flat parts, which extend radially with respect to the axis of the base body. In this way, on the one hand, a sufficient flexibility of the thermal insulating means is achieved, thus providing a pleasant feeling to the user, and, on the other hand, the thermal insulating means is conferred, in all directions, sufficient stability. so that the air chambers, also in a compressed state, maintain sufficient dimensions for thermal insulation. In addition, the flat parts can be made of porous plastic, to preserve the thermal insulating properties and not form any heat transfer bridge. The flat parts may possibly present discontinuities, to join together, within the circulation, contiguous air chambers and thus increase the ductility, with a certain damping effect.

The window of the radiation thermometer is formed by a window foil, which allows infrared radiation to pass through, or the window of the radiation thermometer is covered with such a foil; This window-foil can be transformed, in a seamless embodiment, into a flexible outer foil of the thermal insulating medium that covers the base body. To stabilize the protective cap, a support device can be used, for example in the form of an annular body, which can be attached for example on the edge of the base body and which keeps the sheet smooth.

According to the characteristics of claim 12, a simple manufacture of the protective cap is achieved, since the window area does not have to be covered when placing the additional structures, but is also provided with thermal insulating material. Only then is the window formed by compression, hot stamping or cold stamping. In this case, the air chambers and the porous plastic are compressed so that almost transparent windows are formed.

The preferable material for the base body and the window is polyethylene (PE) or polypropylene (PP). The preferred material for additional structures, as a thermal insulating medium in the form of a porous, thermal insulating plastic, is for example polyethylene (PE), polyvinyl or polyurethane (PU).

The second problem is solved, according to a second invention, with the features of claim 16. Here, the protective cap is only made of thermal insulating material, such as porous plastic or plastic material with air chambers. Here, the window is then brought to the necessary thickness and to the necessary permeability for infrared radiation, by hot or cold stamping.

Further details and characteristics of the invention are given in the following description of exemplary embodiments, on which the figures are taken as a basis.

Figure 1 is a sectional view, along the axis of the infrared optics of a radiation thermometer, with a protective cap according to the invention, placed thereon, the thermal insulating means of the protective cap being a porous plastic.

Figure 2 shows another section of a protective cap, in which the porous plastic thermal insulating medium is only provided in the front area of ​​the protective cap,

Figure 3 shows a section of a protective cap, in which the thermal insulating means is formed by air chambers.

Figure 4 shows a section II of the protective cap of Figure 2, and

Figures 5 to 7 show various sections according to lines II-II of Figure 3, transversely to the axis of the protective cap, according to the various interior constructions of the protective cap or of the thermal insulating means.

On the front end of the probe for temperature measurement 30 of an infrared radiation thermometer 1, which can be used as a thermometer to measure fever, is attached, as shown in figure 1, a protective cap 2 to protect, on the one hand, the probe 30 and prevent it from getting dirty and, on the other hand, to form a thermal insulation when it is inserted into a cavity of the body 31. The body cavity 31 is constituted, in FIG. 1, by the atrial canal 32 of a person, although it is only offered here as an indication.

To measure the body temperature of a person, the temperature measuring probe 30 is inserted into the atrial canal 31 of the ear 32 of a user. In a radiation thermometer without the protective cap 2, the infrared radiation emitted by the eardrum (not shown) and the atrial canal 31 penetrates through a window 3 permeable to infrared radiation in the relevant measurement zone, at the front end of the probe to measure temperature 30 and is carried, by means of an infrared waveguide 5, which runs coaxial with respect to axis 6 of the probe to measure temperature 30 or of the fitted protective cap 2, up to an interference filter 7, penetrating an infrared sensor 4. The increase in temperature caused by the infrared sensor 8 causes a voltage

ES 2 200 149 T3 electrical output, from which the radiation temperature determined through an analyzer unit, not shown, is shown to the user, for example by means of a digital indication (not shown) housed in the box 9 , represented only schematically. As can be seen in figure 1, the waveguide 5 and the infrared sensor 8 are fastened with the filter 7, on the one hand, in a support 10, which can be made of metal, and on the other hand, frontally by means of the tube 4 of the probe to measure the temperature 30, fitted on the box 9. The tube 4 is preferably made of plastic.

The tube 4 is slightly conical towards its free end, into which the window 3 is integrated, with a terminal area 11 lowered in a staggered manner, which narrows and which, at its end, corresponds to the outer diameter of the infrared waveguide 5. Due to to this narrow end zone 11, the thermometer for measuring fever can be used both with children, who have a relatively narrow atrial canal 31, and with adults, with a larger atrial canal 31.

The attached protective cap 2, as shown in Figure 1, has a tubular base body 12, with a narrow wall, tapering conically towards its free end, made of plastic material. On the outer face of the base body 12, a porous plastic 13 has been applied as a thermal insulating medium in this embodiment. In a second embodiment, which is not shown here, the protective cap 2 is made solely of porous plastic 13 or of a cellular configuration of air chambers.

At the free front upper end 14, the protective cap 2 is closed with an infrared window 15, formed by a thin film, permeable to infrared radiation in the radiation range relevant for temperature measurement. In Figure 1, the sheet forms the base body 12 or is attached as a separate part to the base body 12, for example by weaving it. In the case of a protective cap made solely of porous plastic, the window foil 15 is formed from the porous plastic, by pressing or hot stamping.

Since a sheet of this type 15 must be very thin, on the one hand, so as not to influence the measurement through possible emissions of the material, it can be a problem to hold such a sheet, without folds, at the front end 14 protective cap 12. To this end, a ring support 26 is provided in the embodiment shown, which is also shown in the embodiment of FIGS. 2 and 3, which is clamped on the front edge of the base body 12 or is injected in one piece with the protective cap

two. The support ring 26 can also be made of another stronger material.

At the lower end, according to FIG. 1, the protective cap 2 ends with an annular protrusion 16 which is fixed to the outer wall of the temperature measuring probe 30, thus reinforcing and centering the protective cap 2. On the inside face of the protuberance 16, on the one hand, and / or on the outside face of the tube 4, on the other hand, projections, not shown, and / or cavities can be provided, so that the protective cap 2 can be hooked in the area of ​​this protrusion 16 on the outer face of the tube 4 to thereby ensure a secure seat of the protective cap 2 on the temperature measuring probe 30. The protrusion 36 serves at the same time to better handle the protective cap, as it is held by hand by the protrusion 16 and is fitted over the front end of the probe to measure the temperature 30; By grasping the annular protrusion 16, the protective cap 2 can easily be detached from the projections or cavities.

The porous plastic thermal insulating material 13 of the protective cap 2 according to FIG. 1 has its maximum wall thickness approximately in the center, between the front end 14 and the annular protrusion 16. The base body 12 should present, at least in its upper area that covers the narrowed end area 11 of the tube 4, a certain flexibility, so that when used, particularly in a narrow atrial canal such as that of a child, it is It can deform with respect to the axis 6, so that it is almost in contact with the outer wall of this end zone 11 of the tube 4. When introducing the temperature measurement probe of this thermometer 1 with the protective cap 2 in another atrial channel, the base body 12 remains almost in the position shown in figure 1, producing adaptation to the atrial channel solely due to the ductility of the ear canal. soft foam plastic material 13 and to the penetration depth of the temperature measurement probe 30 into the atrial canal 31.

However, there is also the possibility of dimensioning the protective caps 2, so that their base body 12 has an external shape such as that given by the tube 4. These protective caps with an end narrowed in this way can only be preferably fitted to thermometer 1 when it is used to measure the temperature of children. In this case, no free space 17 is needed between the outer face of the end zone 11 of the tube 4 and the inner face of the base body 12.

Due to the thermal insulation properties of the porous plastic 13, the transmission of heat from the atrial canal 31, which is at body temperature, to the generally cooler tube 4 is prevented, since an indication could otherwise occur wrong temperature. The thermal insulating protective cap 2 therefore improves, independently of preventing the window 3 and the outer face of the tube 4 from getting dirty, the measurement accuracy of the thermometer 1, and consequently measurement errors due to transmission are avoided. from ear 32 to tube 4. The protective cap 2 has to be changed for hygienic reasons, after each measurement.

In figure 2, an embodiment of the protective cap 2 is shown, in which the thermal insulation means is provided in the form of soft and ductile porous plastic 13, only in the front, narrow area, while the middle The bottom of the base body 12, which is closed with the annular protrusion 16, is left uncoated, ie uncoated. Applying the thermal insulation material only to the front end of the base body 12 may be sufficient, since the protective cap 2 practically comes into contact with an ear canal 31 with its front end region. It will be necessary to ensure that the thermal insulation means enclose a significant part of air. For this, a porous plastic 13, with a large pore, can be used, preferably a porous plastic 13 with closed pores, so that no dirt can be deposited or introduced into the

ES 2 200 149 T3 porous plastic.

Figure 3 shows another possibility of providing a thermal insulation means on the outside of the base body 12, which contains a considerable amount of air. In this embodiment of the protective cap 2, which has practically the same cross-sectional shape as the protective cap 2 of FIG. 1, an air chamber 18 is located on the outer face of the base body 12, limited by outside by another sheet or wall 33. The ductility of such a protective cap 2 can be adjusted, on the one hand, by means of the pressure with which the chamber 18 is filled with air and, on the other hand, by means of the ductility of the wall 33 and the base body 12 itself.

The protective cap 2 can have thermal insulation means made of porous plastic material or also in the form of other air chambers. The outer wall 19 of a sheet is attached to the outer contour of the porous plastic body 13, downwards, which forms with the base body 12, a lower air chamber 20, so that the thermal insulation means is in the upper zone of the porous plastic 13, while in the lower zone it is formed by one or more air chambers 20 (represented by dashed lines).

In Figures 5 to 7, various sections of the protective caps 2 are schematically represented, showing various possibilities of the internal structure, both in the form of porous plastic materials and in the form of air chambers or combinations of both measures, such as means of thermal insulation. In principle, as shown in figure 4, the thermal insulation means can be in the form of a closed porous plastic body, which covers the outer face of the base body 12, according to the embodiment of figure 1 (interconnected) and of Figure 2 (only in the upper area), or as a circulating air chamber 18, according to the embodiment of Figure 3.

However, there is also the possibility of covering the base body 12 with flat porous plastic parts 22 (figure 5), regularly distributed around its periphery, which are compressed when the thermometer 1 is inserted into the ear canal 31. The spaces Free 34 between the flats 22, of which four are provided in the embodiment of FIG. 5, then form, together with the ear canal 31 (FIG. 1), individual air chambers 34. However, the flat parts 22 can also be made of porous plastic material, the resistance of which is chosen such that, on the one hand, the air chambers 34 are sufficiently reinforced so that the outer wall 24 which delimits the air chambers 34 does not is in contact with the base body 12, although it has to be soft enough, and therefore ductile, to provide the user with a pleasant sensation when inserting the thermometer into the ear canal.

Another variant of execution is shown in FIG. 6. Here, the outer wall 24 is connected to the base body 12 by means of flat, thin, membrane-like portions 25 that separate the air chambers 18. In FIG. 6, a total of eight flat parts 25 are provided, so that, on the outer perimeter of the base body 12, a total of eight air chambers 18 separated from each other are formed. To increase comfort, the flat parts 25 may have discontinuities, not shown, so that the adjoining air chambers 18 are joined in the direction of flow, to allow pressure compensation between the adjoining air chambers 18 and achieve this way a better contact and adjustment with the atrial channel 31.

In figure 7, another example of embodiment is shown, in which in addition to the protective cap 2, shown in figures 1 and 2, another thermal insulation means 23 has been placed on the inside face of the base body 12, by Porous plastic example too.

In summary, with the protective caps, represented in the figures, the following advantages are obtained:

- with the protective cap 2, the distorting heat input in a fever thermometer is reduced, thereby improving the measurement accuracy of the thermometer 1 and / or a smaller (or simpler and cheaper) optics is possible for the thermometer, with less thermal insulation and lower thermal mass.

- due to the protective cap 2, the cooling of the ear canal 31 during the measurement is reduced, thereby increasing the measurement precision of the thermometer 1, making it possible to dispense with any compensations.

- due to the less cooling of the ear and the elastic and soft protective cap 2, the measurement is much more pleasant for the user, in particular for children.

- with the soft protective cap 2 on the outside, the risk of injury is reduced.

- in combination with a fever thermometer, the described protective cap 2 allows a faster temperature determination in children and adults, without causing any pain. Due to its deformability, the protective cap 2 can adapt to various diameters of atrial channels 31 and an optimal penetration depth and centering of the thermometer 1 in the atrial channel 31 is possible.

It is also possible to use protective caps 2 with different outer diameters, for example for children and adults, on the same thermometer 1.

Due to the integrable support ring 26, the window 3 or the window foil 15 of the protective cap 2 can receive a defined, regular tension, the consequence of which is a uniform transmission. In this way, a possible undefined tension of the window 3 is avoided when the protective cap 2 is fitted.