FI61762C - TEMPERATURINDIKATOR - Google Patents

Description

R3f ^ l [B] (11) NOTICE OF ADVERTISEMENT. 1 „1 J; UTLÄGGN I NGSSKRIFT D i / 62 C Patent aycnctty 10 09 1932 'Patent meddelat ^ ^ (51) Kv.lk?/Int.CI.3 g 01 K 11/06 g Q | ^ | j J ^ A N D (11) P »t« nttlhik «mu» - Pitcntanxeknlnj 2087/71 (22) HtkMiiipilvi - An * eknlnpd «| 22.07.71 (23) Alkupftlvi — Gl (tl (h «tsda | 22.07.71 (11) Tullut | ulklMk * l - Bllvlt offwttllf 25.01.72

National Board of Patents and Registration »(44) Date of registration and date of registration. -

Patent-och registerstyrelaen Antttktn uttagd oeh uti. * Krift * n pubiiccrad 31.05.82

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01 + .03.71 USA (US) 58001, 120998 (71) Bio-Medical Sciences, Inc., 1 ^ + 0 New Dutch Lane, Fairfield, New Jersey 07006, USA (US) (72) Sigismund Sagi, Parsippany, New Jersey , Berel Weinstein, New York,

New York, USA (7 ^) Oy Kolster Ab (5I +) Temperature Indicator - Temperature Indicator

For years, the conventional mercury thermometer has been the only temperature indicating device that has been widely used in clinical use to measure human body temperature as well as other types of temperature determinations. However, this type of thermometer has several disadvantages due to both its structure and method of use, and almost anyone who has had to use such a thermometer is well aware of these disadvantages. For example, at least 3 minutes are usually required to obtain a temperature reading, and once the thermometer has been used, it must be sterilized before the next clinical use. The poor structure of such a thermometer, the toxic nature of mercury, the expensive cost of the meter, and the care required in packaging, transporting, and storing them are just a few of these disadvantages.

Prior to this, it has been proposed to use a variety of other thermometer grades to replace the standard mercury thermometer. One such thermometer is a so-called "disposable type" and does not use mercury as a heat-sensitive substance. their use is limited to temperature measurements in the range 36-38.5 ° C and their accuracy is limited to 1/4 ° C which precludes their use in more accurate temperature measurements, and in practice they do not provide accurate clinical information on human body temperature during the fever cycle, where the temperature is often above 38.5 ° C and sometimes as high as 39.5 ° C or even 40.5 ° C. Another disadvantage of these thermometers is that the accurate determination of the temperature depends on the complete change of state of the heat-sensitive materials used. opaque chin from one substance to a transparent liquid is necessary to obtain a proper temperature reading in thermometers such as those described above.

Another type of temperature measuring device is also known, in which the thermometer is provided with several cavities, each of which contains a different heat-sensitive mixture which melts in different temperature ranges. Any such heat sensitive mixture used in such a thermometer is normally opaque below a specified temperature and becomes transparent above a specified temperature. However, even in this case, an indication of the temperature is obtained due to the complete change of the state of the heat-sensitive substance in each cavity. In addition, 45-50 different chemical compounds are always required to cover the desired clinical temperature range.

There are also other types of thermometers that have been proposed for use as a replacement for a conventional mercury thermometer. Electronic thermometers, for example, have been proposed for this purpose. In this type of temperature meter, the detection elements consist of metal wires covered with disposable coatings. However, such electronic thermometers are generally clumsy and large in size, very expensive to manufacture, and require periodic recharging, calibration, maintenance, and frequent sterilization.

Thus, despite all attempts to provide a more suitable thermometer, the conventional silver thermometer is increasingly the most widely used and most common and widely used temperature measuring device in homes and various facilities such as hospitals and medical and industrial laboratories.

The object of the present invention is to provide a temperature indicator that can be used as disposable thermometers for measuring the temperature of the human body and also for other temperature measurement purposes.

The temperature indicator according to the invention is characterized in that it consists of a thermally conductive substrate with a plurality of spaced-apart confined areas in which are placed as many solid solutions of at least two organic compounds of varying composition consisting of at least two organic compounds. the proportions vary but the components are the same as in the binary mixtures are 1-menthol / d, 1-menthol, dimethyl succinate / dimethyl oxalate, 4-chloro-2-methylaniline / 4-bromo-2-methylaniline or n-butyl sulfoxide / n-butyl sulfone , preferably o-chloronitrobenzene / o-bromonitrobenzene, wherein the relationship between the melting point and composition of the solid solutions is substantially linear over the entire range of change, and indicator devices in contact with the solid solutions and used to detect the melting of individual solid solutions. of.

According to the invention, solid solutions are used in which the change of state takes place rapidly in a very narrow temperature range, so that the temperature measurement can be achieved with an accuracy of 1/10 ° C and the temperature can be measured in the clinical range, i.e. 36-40.5 ° C, or even wider.

With the aid of an indicator system based on a heat-sensitive material, a change in the state of such a material and thus the temperature of the measured object can be quickly detected visually.

The purpose of the use of certain organic compounds according to the invention is to lower the onset melting temperature of heat-sensitive materials which actually melt at temperatures above the clinical range.

The features of the invention will become more apparent from the following description with reference to the accompanying drawings. In this specification, the terms "heat-sensitive material", "heat-sensitive material", "temperature-indicating mixtures" and "solid solutions" are used to mean the same materials used. The structure and arrangement of the various parts of the thermometer used in accordance with the invention are described in detail in U.S. Patent 3,677,088.

In the accompanying drawings, in which the same numerals denote the same parts. show: 61762 Fig. 1 is a plan view of a thermometer embodying the principles of the invention, Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. 1, Fig. 3 is a solid solution liquefaction curve of ortho-chloronitrobenzene and ortho-bromonitrobenzene.

The strip, shown in dotted lines in this diagram, shows the accuracy limits of the temperature measurements, i. 2/10 degrees Fahrenheit. The width of the tape is exaggerated to clarify the presentation.

Figure 4 shows the liquefaction curves for solid solutions of para-dichlorobenzene and para-bromochlorobenzene to which naphthalene (lower curve) or triphenylmethane (upper curve), respectively, have been added. Also in Figure 3, the band between the dotted lines (width exaggerated) shows the accuracy limits of the temperature regulations when using these curves. The details of Figure 4 are described below.

As can be seen from the drawings and in particular from Figures 1 and 2, Figure 1 shows a thermometer 1 with a stem part 3 and a pointing part 5 intended to be fitted to the mouth for performing temperature measurements.

The indicator part 5 comprises a plurality of cavities or areas 7 which are suitably spaced apart and divided by the indicator part of the device, as shown in Fig. 1. Each cavity is filled with a temperature-indicating mixture 9 which melts at a precise and predetermined temperature which differs from the melting point of the mixture in the next adjacent cavity by 2/10 degrees Fahrenheit. Although several regions 7 are shown in Figure 1, it is understood that only one such region may be used in cases where temperature measurement is not performed for clinical purposes but to determine some predetermined temperature or thermal condition of the test piece.

It is further shown from Figure 2 that the thermometer 1 has a support plate 11 with the above-mentioned cavities 7. Only two such cavities are shown on an enlarged scale in order to improve the clarity of the figure.

The support plate, i.e. the base plate 11, is usually formed of a plate of flexible heat-conducting material, such as aluminum foil. This ensures the rapid transfer of heat from the test object or person to the heat-indicating mixtures in said cavities. Although aluminum foil is very suitable for this purpose, other materials can be used as well, e.g.

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copper, silver, gold, stainless steel or any other heat conducting plate. It is natural that the thermally conductive plate 11 should be made of a material having good thermal conductivity, a relatively large contact area with the heat measuring object and its thickness should be as small as possible, but still retain a uniform structure so that heat can flow quickly in said cavities. heat-sensitive substances. When aluminum foil is used as a support sheet, its thickness may be between 0.03 and 0.10. In any case, the choice of such a thermally conductive support plate is known to a person skilled in the art and will therefore not be explained in more detail in this context.

On top of and in direct contact with the temperature indicating mixture there is an indicator layer 13 and a cover layer 15 located on top of the former. The combined indicator layer and cover layer are hereinafter referred to as "detection system" or "detection devices".

The transparent layer 17, which may be, for example, polypropylene, "Mylaria" / polyester such as poly (ethylene terephthalate) /, nitrocellulose, polyvinyl chloride, etc., is arranged as a cover film concentric with the support plate 11 and fixed thereto with an adhesive or other in an appropriate way. For example, in order to provide a sufficiently strong structure of the thermometer and to avoid contact between the mouth and the aluminum foil, the carrier layer 11 is provided with a lower coating layer 19 (usually of the same material as layer 17) concentric with and on the lower surface of the carrier sheet covering said cavities . This lower layer is usually attached by gluing to a support plate.

The thickness of the lower cover layer is usually about 0.03 to 0.10 to promote heat conduction from the object to be measured to the conductive sheet 11 and thus to the heat-sensitive materials in said cavities.

If desired, a thermally conductive metal powder can be added to the lower cover layer to improve its thermal conductivity properties. Powdered aluminum metal has been found to be very suitable for this purpose.

Although Figures 1 and 2 show the structure of a commonly used thermometer, it will be appreciated that a number of structural changes may be made without still affecting the applicability of the invention. Other embodiments of this type of thermometer are discussed in more detail in the aforementioned U.S. patent application.

It has now unexpectedly been found that certain organic compounds (described in more detail below) form solid solutions which undergo a change of state at very well-defined temperatures. The term "solid solution" is well known and usually refers to a homogeneous solution of a solid in another solid. "Solid solution" may also mean the dispersion of one solid in another solid, the resulting mixture being homogeneous throughout.

The solid solutions of the invention consist of two different organic compounds with varying mixing ratios. In each solid solution, a rapid change of state occurs at a well-defined temperature.

It has further been found that the solid solutions of the invention used in clinical applications undergo a change of state at well-defined temperatures, with the temperature of the solid state change in each cavity being approximately 2/10 degrees Fahrenheit (1/10 degrees Celsius) different from the solid solution in the adjacent cavity. the temperature of the state change. Thus, for example, in clinical applications, when it is desired to perform temperature measurements in the range of 96-105 degrees Fahrenheit (36-40.5 degrees Celsius), 45 different solid solutions (with different percentages in composition but otherwise made from the same component) are all necessary temperature differences with an accuracy of 2/10 degrees Fahrenheit, i.e. 96.0, 96.2, 96.4, etc. up to 104.8 degrees Fahrenheit.

It follows from the above that the selection of organic compounds that meet the above requirements requires careful and careful investigation, as not all organic compounds are suitable for this purpose. On the contrary, those organic compounds which are particularly suitable for forming solid solutions which can be used as temperature-measuring compositions according to the present invention are those which have well-defined common chemical and / or physical properties on the basis of which these compounds are selected.

Thus, it has been found that compounds, especially organic compounds, having an analogous chemical composition (e.g., analogous ά * r? T <r ° 6! / Ϋ .il compounds, homologous compounds, and optical isomers) have substantially the same molecular volume or a similar crystal structure (e.g., isomorphic) form solid solutions useful for the purposes of the invention. In addition, these solid solutions must have a linear or substantially linear liquefaction curve of the mixture, especially over a desired temperature range, such as the clinical temperature range.

Examples of solid solutions of organic compounds whose components meet one or more of the above requirements are the following: A) Ortho-chloronitrobenzene: ortho-bromonitrobenzene B) 1-menthol: dl-menthol C) Acetophenone: benzophenone D) Dimethylsuccinate: dimethyl oxalate E) 4-chloropropiophenone: 4-bromopropiophenone F) 4-chloro-2-methylaniline: 4-bromo-2-methylaniline G) 4-chloroacetophenone: 4-bromoacetophenone H) n-butylsulfoxide: n-butylsulfone I) n-hexane: 2-nonodecane J) Cyclohexane: 2-nonodecane K) c <-chlorocinnamaldehyde: o (.- bromocinnamaldehyde.

Of the above solid solutions, the systems described in A, B, E, F, H and K have been found to be very useful in clinical thermometers for measuring temperatures to 2/10 degrees Fahrenheit or even better. However, those solid solutions prepared from ortho-chloronitrobenzene and ortho-bromonitrobenzene have been found to be most preferably used for temperature measurements in the clinical range with the above accuracy.

The preparation of solid solutions is generally well known to those skilled in the art and need not be described in more detail in this context. Nevertheless, the following description is intended to provide a basis for the preparation of solid solutions which are highly useful in the present invention.

As mentioned above, Figure 3 shows the temperature-composition curve (liquefaction curve) of solid solutions of ortho-bromonitrobenzene and ortho-chloronitrobenzene. As can be seen from this figure, the liquefaction curve is essentially linear.

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In preparing a solid solution of ortho-chloronitrobenzene and ortho-bromo-nitrobenzene, simply mix together the amounts of these components that are calculated to provide a solid solution with a defined melting point. Thus, for example, to prepare a solid solution having a melting point of e.g. 101.4 ° Fahrenheit (101.6 ° C), the amounts of the two components obtained from the curve of Figure 3 are mixed together to obtain the desired melting point. Solid solutions having some other melting points can be prepared in a similar manner using varying amounts of these components, and in any case the exact melting point of these solid solutions is determined before they are added to the thermometer cavities. Solid solutions of other components are prepared in a similar manner.

To clarify the matter, the following table shows the combinations of solid solutions of ortho-chloronitrobenzene and ortho-bromonitrobenzene and the corresponding melting points of these solid solutions:

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Table

Coalition in% by weight Temperature Or to-brominitro- Ortho-chloro-lithro- * 'benzene benzene o o P C; 96.0 35.6 56.2 45.8 96.2 35.7 57.5 42.5 96.4 35.8 58.8 41.2 96.6 35.9 60.1 39.9 96.8 36.0 61.3 38 .7 97.0 36.1 62.5 37.5 97.2 36.2 63.5 36.5 97.4 36.4 64.5 35.5 97.6 36.5 65.5 34.5 97.8 36.6 66.5 33 .5 98.0 36.7 67.5 32.5 98.2 36.8 68.5 31.5 98.4 36.9 69.5 30.5 98.6 37.0 70.5 29.5 98.8 37.1 71.5 28 .5 99.0 37.2 72.5 27.5 99.2 37.4 73.5 26.5 99.4 37.5 74.5 25.5 99.6 37.6 75.5 24.5 99.8 37.7 76.4 23 , 6,100.0 37.8 77.3 22.7 100.2 37.9 78.1 21.9 100.4 38.0 79.0 21.0 100.6 38.1 79.9 20.1 100.8 38.2 80, 8 19.2 101.0 38.4 81.7 18.3 101.2 38.5 82.6 17.4 101.4 58.6 85.5 16.5 101.6 38.7 84.5 15.7 101.8 38.8 85.1 14.9 102.0 38.9 85.9 14.1 102.2 59.0 86.7 13.5 102.4 39.1 87.5 12.5 102.6 39.2 88.2 11.8 102.8 39.4 88.9 11.1 103.0 39.5 89.6 10.4 103.2 39.6 90.3 9.7 103.4 39.7 91.0 9.0 103.6 39.8 91.7 8.3 103.8 39.9 92.4 7.6 104.0 40.0 93.1 6.9 104.2 40.1 93.8 6.2 104.4 40.2 94.5 5.5 104.6 40.4 95.2 4.8 104.8 40.5 96.0 4.0 10 61762

Although the amount of solid solution in each cavity need only be sufficient to moisten the indicator or cause discoloration, in practice and to provide more reliable temperature measurements, a sufficient amount of solid solution must be used in each cavity so that at least 70% of the indicator area is wetted or discolored. It will be appreciated, therefore, that in addition to the amount of temperature-indicating mixture in each cavity, the size of the cavity, the porosity of the indicator and its thickness are some of the key factors to consider and select for rapid visual detection and accurate measurement of temperature in each area. Nevertheless, it should be emphasized that these matters fall within the scope of the person skilled in the art and can be selected on the basis of this explanation without falling outside the scope of the invention.

These cavities can be filled with solid solutions in a known manner, such as, for example, by measuring and adding prescribed amounts to them, or in some other suitable manner suitable for mass production.

As mentioned above, the change in state of the solid solutions in each cavity can be visually detected by an indicator system in close contact with the solid solutions in each cavity. In addition, this indicator system consists of an indicator layer and a cover layer. The indicator layer is usually formed by a highly absorbent paper having a high porosity and absorbency to promote wetting after changes in the state of the heat-sensitive substances in said cavities. This layer can be impregnated with dye or pigment to provide such a color change color indication.

The cover layer is usually paper that has the same properties as the indicator layer, but has a contrasting color.

Thus, after the change of state in the heat-sensitive substance in each cavity, the liquid is rapidly absorbed into the indicator layer and dissolves the dye or pigment therein. The formed dye or pigment solution (or dispersion) passes through the indicator layer into the cover layer, thus facilitating the visual detection of the color change of the cover layer. Thus, the temperature measurements can be made irreversible and the thermometer can be discarded after one use. However, the thermometer can be used for non-clinical applications to measure temperatures 11,617 6 2 higher than the above temperatures.

The color or pigment used can be added to the indicator 15 or it can be added directly to the solid solution. When added to the indicator layer, the latter can be simply dipped in a dye solution or pigment dispersion, or this can be sprayed, or the coating can be performed with such a solution or dispersion. A sufficient amount of dye or pigment must, of course, be used so that the change in color can be rapidly detected visually in each cavity.

If the dye or pigment is added directly to the solid solution, the amounts used should also be sufficient to rapidly detect the color change visually as mentioned above. However, the addition of color or pigment directly to solid solutions can in some cases adversely affect their melting points. Thus, in those cases where accurate temperature measurement is required, i.e. with an accuracy of 2/10 degrees Fahrenheit, the former method is more preferable if the color or pigment selected for this purpose is not known to adversely affect the accuracy of the melting ranges of the solid solutions.

Whether the color or pigment is added directly to the solid solution or combined with the indicator, it is preferable to prevent contact between the solid solution in said cavities and the indicator until the thermometer is used for the actual temperature measurement. This prevents possible fouling of solid solutions due to color or pigment. Thus, a separating layer (not shown) can be used to prevent such contact and possible contamination. Such a separating layer can be torn off when the thermometer is ready for use. Details of the structure of such a separating layer are also described in the aforementioned U.S. patent.

Although indicator devices or systems have been described above with reference to a particular temperature range for a better understanding of the invention, it should be noted that this description is provided for illustrative purposes only and does not limit the scope of the present invention in any way. Other indicator systems can be used to detect temperatures corresponding to changes in the state of solid solutions. A detailed description of such indicator systems is also provided in the aforementioned U.S. patent.

In general, oil-soluble dyes which are compatible with a liquid obtained as a result of a change in the state of solid solutions in the above-mentioned cavities have been found to be very suitable for incorporation into an indicator for the purposes of the invention.

In the case of pigments, it has been found that improved liquid absorption and color detection can be achieved by using pigments with a particle size in the range of 0.2-0.5 μm compared to pigments with a significantly larger particle size, e.g. 1 micron or more. bigger. It should be noted, however, that the advantages of the invention can be obtained by using any color or pigment that promotes a visually detectable change in the state of the solid solution in each cavity.

It should further be noted that, unlike temperature-indicating compositions previously used in the art, even before a complete change in the state of the solid solutions used, the liquid is rapidly absorbed and distributed throughout the indicator system so that the exact temperature at which such a change has taken place can be determined. As a result, it is clear that a complete state change is not necessary for such thermal state measurements.

Although the invention has been described above with particular reference to solid solutions having melting points in the clinical range, i. 36-40.5 ° C, it is to be understood that the invention is not limited to such mixtures. Other solid solutions having melting points above 40.5 ° C, can be successfully used for adding a third component, which is capable of reducing the melting points of such solid solutions, without affecting the nature of the other side of the melting points of linear and Coalition for solid solutions of the components on the other side. Thus, for example, it has been found that para-dichlorobenzene (m.p. 53 ° C) and para-bromochlorobenzene (m.p. 67.4 ° C) can be used to prepare solid solutions with melting points in the clinical temperature range. This can be accomplished by adding certain amounts of naphthalene or triphenylmethane to mixtures of para-dichlorobenzene and para-bromochlorobenzene. Thus, as shown in Figure 4, the upper curve shows mixtures in which the relative amounts of para-dichlorobenzene and para-bromochlorobenzene can be easily detected on the abscissa. The amount of triphenylmethane in the mixture is between 44 and 45% by weight and preferably 45% by weight of the total mixture, i.e. calculated from para-dichlorobenzene, para-bromochlorobenzene and triphenylmethane. Similarly, the amount of naphthalene in the lower curve is between 33 and 34% by weight, and is preferably 13.6% to 33.5% by weight of the total mixture of para-dichlorobenzene, para-bromochlorobenzene and naphthalene.

It can be readily seen that the addition of such third ingredients lowers the melting point of the solid solution to the desired temperature range. It is natural that the third component and the amount required differ from the corresponding values of the other components of the solid solution.

Although the above-mentioned temperature measurement mixtures have been described in connection with thermometers intended for actual temperature measurements, it should be noted that such a description is in no way complete or limiting. Thus, such temperature-indicating compositions may be equally useful in other applications, such as pyrometers and in detecting overheating of transformer motors and other similar electrical or mechanical devices. Of course, for such uses, the temperature indicating system must be modified to suit such a new use. However, such modifications are within the skill of the art and do not alter the nature of the invention. Nevertheless, it must be emphasized that when temperature-indicating mixtures are used to measure temperature in the clinical range, they can be used to determine body temperature with an accuracy of 2/10 Fahrenhelt or even higher.

For clinical temperature measurements when using a thermometer, it is recommended that it be fitted to the mouth in contact with the tongue for 30 to 60 seconds. The thermometer can then be removed and the temperature determined by noting the last area where the color change has occurred (see Figure 1). Although this time is generally satisfactory for performing the temperature measurement with the desired accuracy, i. 2/10 degrees Fahrenheit (or even greater accuracy) is a period of 30 seconds generally found to be appropriate in most cases.

It should further be noted that although the above-mentioned solid solutions have been described in connection with clinical thermometers for measuring body temperature from the mouth, such thermometers can also be used for other types of temperature measurements. However, if they are used for other purposes, the temperature scale must be slightly modified without affecting the accuracy of the temperature readings. This is due to differences in the prevailing environmental conditions that affect the heat transfer rate from the measurement object to 14 61 762 solid solutions. Thus, for example, when using a clinical thermometer to measure the temperature in a liquid bath, the temperature scale shifts 4/10 degrees Fahrenheit relative to the clinical range. Thus, the range that indicates a temperature of 37.4 ° C (99.4 ° F) when performing a temperature measurement from the mouth indicates a liquid bath temperature of 37.2 ° C (99.0 ° F). However, such calibration and adjustment on a temperature scale can be performed in advance for such applications without still affecting the accuracy of the temperature measurements.

Claims (6)

15 617 6 2 1. Temperature indicator, characterized in that it consists of a thermally conductive substrate with a plurality of spaced confined areas containing an equal number of solid solutions of at least two organic compounds of varying composition, consisting of at least two organic compounds having: the proportions of the solutions vary but the components are the same as in the binary mixtures 1-menthol / d, 1-menthol, dimethylsuccinate / dimethyl oxalate, 4-chloro-2-methylaniline / 4-bromo-2-methylaniline or n-butylsulfoxide / n-butylsulfone , preferably o-chloronitrobenzene / o-bromonitrobenzene, wherein the relationship between the melting point of the solid solutions and the composition is substantially linear over the entire range of change, and indicator devices in contact with the solid solutions used to indicate melting of the individual solid solutions. Temperature indicator according to Claim 1, characterized in that the indicator devices comprise a dye or pigment which is soluble in solid solutions. Temperature indicator according to Claim 1, characterized in that the proportion by weight of o-chloronitrobenzene and o-bromo-nitrobenzene is between 43.8: 56.2 and 4.0: 96.0. Temperature indicator according to Claim 1, characterized in that the solid solutions are tertiary mixtures of three organic compounds. Temperature indicator according to Claim 4, characterized in that the amount of one organic compound in the solid solutions is constant and the amount of the other two compounds varies. Temperature indicator according to Claim 5, characterized in that the tertiary mixtures consist of varying amounts of p-dichlorobenzene and p-bromochlorobenzene and a constant amount of triphenylmethane.