CA1159276A - Method for optical determination of saturation temperature and apparatus therefor - Google Patents
Method for optical determination of saturation temperature and apparatus thereforInfo
- Publication number
- CA1159276A CA1159276A CA000370151A CA370151A CA1159276A CA 1159276 A CA1159276 A CA 1159276A CA 000370151 A CA000370151 A CA 000370151A CA 370151 A CA370151 A CA 370151A CA 1159276 A CA1159276 A CA 1159276A
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- Prior art keywords
- light
- test
- test cell
- warmer
- test specimen
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
- G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
- G01N21/534—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke by measuring transmission alone, i.e. determining opacity
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/14—Investigating or analyzing materials by the use of thermal means by using distillation, extraction, sublimation, condensation, freezing, or crystallisation
- G01N25/147—Investigating or analyzing materials by the use of thermal means by using distillation, extraction, sublimation, condensation, freezing, or crystallisation by cristallisation
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method and apparatus for determining the saturation temperature of a solution using the principle that a change in the temperature of the solution causes a correlatable change in light transmitted through the solution. The apparatus, unlike prior art apparatus, prevents the condensation of steam evolved from a test solution in the vicinity of a test cell; and the method overcomes the problem of suspending solute crystals in the test solution by depositing such crystals on an inner surface of the test cell. The apparatus and method disclosed provide accurate and precise results.
A method and apparatus for determining the saturation temperature of a solution using the principle that a change in the temperature of the solution causes a correlatable change in light transmitted through the solution. The apparatus, unlike prior art apparatus, prevents the condensation of steam evolved from a test solution in the vicinity of a test cell; and the method overcomes the problem of suspending solute crystals in the test solution by depositing such crystals on an inner surface of the test cell. The apparatus and method disclosed provide accurate and precise results.
Description
5~;~7G
This invention relates to a method and apparatus for optical determination of the saturation temperature of a solution.
A broad object of the present invention is to provide a method and apparatus for optical determination of the saturation temperature of a solution which obviate or mitigate the disadvantages, as described below, associa-ted with the prior art.
In one aspect, the present invention provides a method for the optical determination of the saturation temperature of a given substance in a solution subject to test by a procedure involving the steps of placing the solution in a test cell, suspending therein fine crystals of the solute dissolved in the solution thereby preparing a test specimen, mounting the test cell now containing the test specimen on a mounting base formed in a tempera-ture-adjustable heater, gradually elevating the tempera-ture of the test specimen and throwing a light upwardly at the test specimen, receiving the light penetrating through the test specimen on a photoelectric element and calculating the saturation temperature based on the tem-perature of the test specimen and the amount of electricity -generated in the photoelectric element, which method is : characterized by causing the fine crystals of the solute to be deposited fast in the form of a thin layer on the light-penetrating surface of the test cell and then pour-ing the solution on the deposited thin layer to prepare a test specimen, mounting the test cell containing the test specimen on the mounting base, gradually elevating : 30 . J -- _ ~5~'~`7~
the temperature of the test specimen and throwing light upwardly at the test specimen, at that time an empty space on the cell is made as a closed e~lpty space and pre-heated air is passed through the closed empty space.
In a further aspect, the present invention pro-vides an apparatus for optical determination of the satura-tion temperature of a given substance dissolved in a solu-tion under test which comprises a light source; a light receiving unit above the light source, and having a light receiving element and a first light path therein; a warmer positioned between the light sou.rce and the light receiving unit, the warmer having a secona light path therethrough;
a test cell supported by the warmer and extending through the second light path; an air seal glass supported by the warmer, the air seal glass being positioned above the test cell and extending through the second light path such that the distance between the test cell and the air seal glass is between 0.5 mm and several mm; the warmer being capable of warming the test cell; whereby light emitted from the light source passes through the second light path, the test cell, the air seal glass and the first light path, and is received by the light receiving element so as to optically determine the saturation temperature; the test cell, warmer and air seal glass forming a substantially closed space; air ducts pierced through the warmer and communicated with the closed space; and means to introduce a drying fluid to the closed space through the air ducts.
Embodiments of the invention, by way of example, and of the prior art will now be described with reference . 2 -., , J2`~
to the accompanying drawings in which:
Fig. 1 is a sectional side view illustrating, in general outline, an apparatus according to this inven-tion;
Fig. 2 is a cross-section as viewed along the line II-II of Fig. 1~
Fig. 3 is a partial sectional side view illus-trating the steps for placing a test cell and an air seal glass in the apparatus of Fig. l;
Fig. 4 is a sectional side view illustra-ting, in general outline, a conventional prior art apparatus;
Fig. 5-a is a sectional side view of a typical test cell;
Fig. 5-b is a sectional side view illustrating the deposition of fine crystals on the lower surface of the cell;
Fig.5-c is a sectional side view of a typical test cell of improved design;
Fig. 5-d is an elevation of the test cell of Fig. 5-c; and Fig. 6 is a diagram of the characteristic curves representing the relation between temperature and time;
and current and time.
; Recently, an improved saturation temperature meter designed for optical determination of saturation temperature has been reported in the International Sugar Journal, Vol. LXXX, 1978, pp 40-43 (published at 23a Easton Street, High Wycombe Bucks, England).
.-,, , " ~276 As illustrated in Fig. 4, this temperature meter is coMposed primarily of a light source 101, a heating unit 100 :
provided with a light path 104 and a mount 103 for a test cell 102, and a light-receiving unit 106 provided with a light-receiving elernent 105.
The ter,lperature meter is prepared for operation by placing a test solution in the test cell 102, adding and suspending fine crystals of the solute in the solution to obtain a test specimen, mounting the test cell 102 containing the test ~ -specimen on the cell mount 103 and placing the heating unit 100 on top of the light-receiving unit 106. At this point, a space 108 is formed between a heat retaining glass 107 disposed in the lower port.ion of the light-receiving unit 106 and the test cell 102.
With the meter so preparedl light indicated by arrow 109 is admitted via the light path 1()4 upwardly towards the lower end of the test cell 102; and a heater 110 is switched on to effect gradual indirect heating of the test specimen in ` ; the test celL 102~ As the heating is continued, the temperature ~
20 of the test specimen increases and eventually reaches a point ~.
at which the fine crystals in the test specimen are dissolved. ~ ~:
:: :
: At this point, the light penetrating through the test cell 102 .
increases because the scattering of light is decreased on dissolution of the fine crystals and, consequently, a relatively :
large change occurs in the amount of light being continuously received by the light-receiving (photoelectric) element 105~ ~;
This change manifests itself in the amount of electric current generated by photoelectric conversion in the photoelectric element 105. The temperature of the test specimen is continuously measured by a temperature measuring unit 111 which ~' ~L~L5~276 is held in contact with the lower surface of the -test cell 102.
This temperature meter, therefore, indicates the saturation temperature of the solution under test with reference to the aforementioned change in current generation and the corres-ponding -temperature of the test specimen.
In a conventional saturation temperature meter such as described above, during the elevation of the temperature of the test specimen, the test specimen in the test cell 102 and gas in the space 108 thermally expand. Consequently, an increased portion of the gas and a small volume of steam issuing from the surface of the test specimen leak into and fill the space 108, giving rise to a state of stearn saturation.
In this case, the relation between the temperature of the test cell 102 (Tl) and that of the heat retaining glass 107 (T2) is Tl > T2 under normal working conditions. Consequently, part of the steam filling the space 108 comes into contact with the surface of the heat retaining glass 107 and forms dew-condensa-tion thereon.
~: Experience shows that where the temperature (T2~ is in : 20 the range of from 5 to 10 C, dew-condensation occurs when the temperature diference (Tl - T2) is about 0.2C; and that when the temperature (T2) falls within the range of from 25 to 30C, dew-condensation ensues when the temperature difference (Tl-T2) is about 1 C.
When dew-condensation forms as described above, it causes scattering of the liyht penetrating through the test cell 102 to impair the accuracy of determination. If the heating rate is lowered enough to preclude dew-condensation, the rate must be significantly reduced such that the determination 30 requires an excessively long time, the change in the intensity ~S~;~`76 of the penetrating light occurs very slowly and the saturation point determined is imprecise.
Further, with the conventional saturation temperature meter9 the test specimen is prepared by suspending fine crystals of the solute in the solution under test. Where the .
solution under test is very pure or where the solution is highly supersaturated the initial crystallization (occurrence of pseudocrystals) either during or after the preparation of the test specimen proceeds very quickly so that the determination demands a high degree of skill or the reproducibility of the determined values is impaired.
With reference to Figs. 1, 2, 3 and 5-a, 1 denotes a warmer which is generally constructed in a cylindrical form from a metal such as cast aluminum which excels in thermal conduc-tivity. Inside the warmer 1, a heat generator 2 i5 buried and ; used for elevating the temperature o:E the warmer 1 to a desired level. The heat generator 2 can be, for example, an electric heating coil capable of being adjusted to a desired temperature.
; The warmer 1, at the center thereof, contains a vertical cylindrical opening to form a light path 3. The light path 3 is so disposed that the light from a light source 4 positioned under the light path 3 is collecte~ by a lens 5 and passed :.
upwardly through the light path 3. Inside the warmer 1, in the upper part of the light path 3, a mounting base 6 is formed for supporting an air seal glass 7 concentrically relative to the light path 3. This mounting base 6, which serves as a mounting base for the air seal glass 7, has a diameter greater than the diameter of the light path 3. The mounting base 6 supports the air seal glass 7 perpendicular to the light path 3. At a prescribed distance below the moun-ting base 6 for the air seal z~
glass 7, a mounting base 8 for supporting a test cell 9 is concentrically formed rela-tive to -the mounting base 6. This mounting base 8, which serves as a mounting base for the test cell 9, maintains the test cell 9 parallel to the air seal glass 7. l'he distance between the mounting base 6 for the air seal glass 7 and the mounting base 8 for the test cell 9 is so fixed that, when the test cell 9 and the air seal glass 7 are set fast in position on the respective mounting bases 6 and 8, a space 10 within the range of from 0.5 mm to several ~m is formed between the cell 9 and the air seal glass 7. The space 10 is a substantially closed space which is enclosed by the air seal glass 7, the test cell 9 and the inner wall of the warmer 1.
Air ducts 11 fvrmed through the warmer 1 communicate with respective ends of space 10, to permit flow of air through the air ducts 11 and the s~ace 10 in the direction of the arrows.
The test cell 9 is, therefore, heated on both sides, i.e. on its lower side by the heat received clirectly from the warmer 1 ; and on its upper side by the heat from the circulating air which has been heated by the warmer 1.
The test cell 9 is generally formed by inserting a washer 13 made of a corrosion-proof, highly thermoconductive metal such as, for example, brass between two clrcular glass plates 12 and 12' disposed as illustrated in Fig. 5-a. The lower glass plate 12' is joined fast to the washer 13, and the upper glass plate 12 is separably mounted on the washer 13. Thus~
the test cell 9 contains a space for accommodating a test specimen between the opposed glass plates 12 and 12'. A
temperature-measuring terminal 14 is disposed in a position such that it will come into contact with the lower glass plate 12' when the test cell 9 is mounted in position on the mounting base 8 for the test cell 9. Generally, a precision grade thermocouple is used as the temperature-measuring -terminal 14.
Instead of using a construc-tion incorporating a washer as described above, the test cell may be formed by simply combining two transparent glass plates.
Denoted by 15 is a light-receiving unit, which is removably mounted on top of the warmer 1. The light-receivi.ng unit 15 is preferably composed of two different rnaterials; a base 16 made of a heat-resistant synthetic resin of low thermal conductivity and adapted to come into direct contact with the warmer 1 and a member 17 disposed on the base 1~ and adapted to support a photoelectric element 21. To ensure complete dissipation of the heat transmi.tted from -the base 16, in order to protect the photoelectric element 21 from possible temperature elevation, the member 17 is preferably made of a material of high thermal conductivity. Copper i'3 an ideal example of the material for the member 17. By 16' are denoted legs projecting from the lower side of the base 16. These legs 16l serve to form a space between the warmer 1 and the base 1~ and, thereby, form adiabatic insulation. Denoted by 18 is a light path, leading to the light-receiving unit, which is formed coaxially with the light path 3. A heat retaining glass 1~ is disposed below the light path 18 for the light-receiving unit 15. Light which passes through the heat retaining glass 19 projects through a polarizing lens 20 onto the photoelectric element 21.
The photoelectric element 21 is formed of a photosensi.tive matexial such as a photodiode. To support this element 21, a rising portion 22 is formed at the central upper portion of the member 17. Held in a fixed position at all times, the photo-electric element 21 detects the amount of light received via the ~;
"~ .
`7~;
light-receiving path 18. The light which impinges upon this photoelectric element 21 is converted into an electric current An output terminal 23 is connected to the photoelectric element 21. This terminal is ex-tended and connected to a recorder or measuring instrument which is not illustrated.
Now, the operation of the above-described apparatus for the determination of satuxation temperature will be described.
The apparatus is prepared for operation by, ~irst, suspending in a solvent fine crystals of the solute dissolved in a test solution; pouring the resulting suspension dropwise onto the light-penetrating bottom face of the test cell 9;
subsequently vaporizing the solvent by suitable means such as heating, thereby causing the fine crystals of the solute to be firmly deposited in the forrn of a thin layer S on the light-penetrating face as illustrated in Fig. 5-b.
The solvent used should be inert to the solute and should vaporize at an appropriate rate. Where sucrose is used as the solute, for example, acetone proves to be a suitable solvent and brings about a satisfactorily fast deposition o~ the solute. However, in this case, ether vapori~es too rapidly and alcohol vapori~es too slowly to allow the desired fast deposition of the solute. Of course, a mixture of solvents can also be used.
Into the test cell 9, in which the fine crystals have been firmly deposited in the form of a thin layer S as described above, the test solution is slowly poured to cover the upper glass plate 12, completing the preparation of a test specimen.
The test cell 9 containing the test specimen as described above is set in position on the mounting base 8 ~5~Z~
illustrated in Fig. 1. Above the test cell 9, the air seal glass 7 is se-t in position on the mounting base 6. Preparation of the apparatus for the determina-tion is then comp]eted by moun~ing the light-receiving unit 15 on the warmer 1. Then, air circulation through the air duct 11 is started and the heat generator 2 and the light source 4 are switched on.
After 100 parts of light (representing a given incident intensity) have entered the test specimen layer A
(Fig. 1), some part of the light is absorbed by the solution and cell and some part thereof is randomly scattered by the fine crystals forming the thin layer S. Consequently, less than 100 parts of the light penetrates through the cell ~ and reaches the photoelectric element 21, there to be converted into a corresonding amount of electric current.
Proportionally, as the temperature of the test specim~n increases, the amount of light absorbed by the solution increases, hence the light reaching the photoelectric element 21 decreases and the current generated decreases. The curve plotting the current recorded continuously (as a function in mV) with time indicates that the current decreases with the lapse of time (Fig. 6).
As the heating continue~ to a point where the fine crystals forming the thin layer S begin to dissolve, i.e. where the saturation temperature is just passed, the scattering of -the light begins to decrease owing to the decrease in the amount of the fine crystals and the amount of light reaching the photo-electric element 21 suddenly changes to an increasing trend.
Consequently, a point of inflection appears in the curve plotting the continuous change of current generated. The temperature which corresponds to this point of inElection is the saturation temperature of the solution under test. By com~ining the afore-mentioned point of inflection and the temperature of -the test specimen indicated on the temperature-measuring terminal 14, therefore, the sa-turation temperature can be readily determined, as shown in Fig. 6.
The test specimen to be used for the determination as described above is prepared without entailing the step of causing fine crystals of the solute to be suspended in the solution under test as practised conventionally. Thus, the occurrence of pseudocrystals during or after the preparation of the test specimen is precluded and, consequently, the determination affords accurate results.
Further, as described above, air which has been warmed by the warmer 1 is blown into the space 10 formed by the tes-t cell 9. The surface temperature of the air seal glass 7 defininy the upper boundary oE space 10, therefore, is substan-tially equal to the temperature of the test cell 9. Therefore, steam leaking from the cell 9 due to thermal expansion thereof does no~ form dew-condensation in the space 10 as experienced with conventional apparatus. Since the leaking steam is constantly purged out of the space 10 by the current of air flowing through the air duct 11, no steam stagnates anywhere within the space 10.
The improvements noted above serve to expedite the determination and, at the same time, greatly enhance the reproducibility of the results obtained.
For the purpose of comparison, the method and apparatus described herein and those of the conventional techni~ue were used to determine the saturation temperature of a sucrose solution. The resul-ts were as shown in Table 1. Comparison ~1' ~5~2`~i of the precision of determinal_ion,: expressed in terms of standard deviation (S.D.) of the measured values, reveals that the S.D. of the results obtained by -the method described herein was relatively small and the average value agreed closely with the theoretical value.
The procedure for tl~e determination and the results of the determination (Table 1) are explained below:
This invention - the procedure followed for the preparation of .
the apparatus (as shown in Fig. 1) comprised suspending in acetone a small amount of suc:rose crystals pulverized in ad~ance to a particle size of not more than 200 mesh; pouring the resultant suspension dropwise and gradually onto the light-penetrating bottom surface (glass plate 12') of the test cell 9 mounted on a hot plate heated to from 80 to 100C; allowing the fine crystals to form an apparently uniform thin layer;
vaporizing the acetone thereby causing the thin layer of fine crystals to be firmly deposited on the glass plate and, on completion of the deposition of the fine crystals, allowing the : test cell 9 to cool; gently pouring into the test cell 9 a sucrose solution having a pur:ity of 99% and a total solids content o~ 75% (w/w); and covering the test cell 9 with a cover ~glass plate 12). Then, by following the procedure described above, determining the saturation temperature by heating the test specimen at rate of 5 C/minute.
Conventional techni~ue - a test specimen was prepared by gently stirring about 5 y of a sucrose solution having the same purity and concentration as mentioned above with 1 to 2~
W/V, based on the sucrose solution, of a more or less ~et powder sucrose obtained by ce:ntrifuging sucrose crystals of a particle size not exceeding 200 mesh in an alcohol, thereby _ 12 -~j ~
This invention relates to a method and apparatus for optical determination of the saturation temperature of a solution.
A broad object of the present invention is to provide a method and apparatus for optical determination of the saturation temperature of a solution which obviate or mitigate the disadvantages, as described below, associa-ted with the prior art.
In one aspect, the present invention provides a method for the optical determination of the saturation temperature of a given substance in a solution subject to test by a procedure involving the steps of placing the solution in a test cell, suspending therein fine crystals of the solute dissolved in the solution thereby preparing a test specimen, mounting the test cell now containing the test specimen on a mounting base formed in a tempera-ture-adjustable heater, gradually elevating the tempera-ture of the test specimen and throwing a light upwardly at the test specimen, receiving the light penetrating through the test specimen on a photoelectric element and calculating the saturation temperature based on the tem-perature of the test specimen and the amount of electricity -generated in the photoelectric element, which method is : characterized by causing the fine crystals of the solute to be deposited fast in the form of a thin layer on the light-penetrating surface of the test cell and then pour-ing the solution on the deposited thin layer to prepare a test specimen, mounting the test cell containing the test specimen on the mounting base, gradually elevating : 30 . J -- _ ~5~'~`7~
the temperature of the test specimen and throwing light upwardly at the test specimen, at that time an empty space on the cell is made as a closed e~lpty space and pre-heated air is passed through the closed empty space.
In a further aspect, the present invention pro-vides an apparatus for optical determination of the satura-tion temperature of a given substance dissolved in a solu-tion under test which comprises a light source; a light receiving unit above the light source, and having a light receiving element and a first light path therein; a warmer positioned between the light sou.rce and the light receiving unit, the warmer having a secona light path therethrough;
a test cell supported by the warmer and extending through the second light path; an air seal glass supported by the warmer, the air seal glass being positioned above the test cell and extending through the second light path such that the distance between the test cell and the air seal glass is between 0.5 mm and several mm; the warmer being capable of warming the test cell; whereby light emitted from the light source passes through the second light path, the test cell, the air seal glass and the first light path, and is received by the light receiving element so as to optically determine the saturation temperature; the test cell, warmer and air seal glass forming a substantially closed space; air ducts pierced through the warmer and communicated with the closed space; and means to introduce a drying fluid to the closed space through the air ducts.
Embodiments of the invention, by way of example, and of the prior art will now be described with reference . 2 -., , J2`~
to the accompanying drawings in which:
Fig. 1 is a sectional side view illustrating, in general outline, an apparatus according to this inven-tion;
Fig. 2 is a cross-section as viewed along the line II-II of Fig. 1~
Fig. 3 is a partial sectional side view illus-trating the steps for placing a test cell and an air seal glass in the apparatus of Fig. l;
Fig. 4 is a sectional side view illustra-ting, in general outline, a conventional prior art apparatus;
Fig. 5-a is a sectional side view of a typical test cell;
Fig. 5-b is a sectional side view illustrating the deposition of fine crystals on the lower surface of the cell;
Fig.5-c is a sectional side view of a typical test cell of improved design;
Fig. 5-d is an elevation of the test cell of Fig. 5-c; and Fig. 6 is a diagram of the characteristic curves representing the relation between temperature and time;
and current and time.
; Recently, an improved saturation temperature meter designed for optical determination of saturation temperature has been reported in the International Sugar Journal, Vol. LXXX, 1978, pp 40-43 (published at 23a Easton Street, High Wycombe Bucks, England).
.-,, , " ~276 As illustrated in Fig. 4, this temperature meter is coMposed primarily of a light source 101, a heating unit 100 :
provided with a light path 104 and a mount 103 for a test cell 102, and a light-receiving unit 106 provided with a light-receiving elernent 105.
The ter,lperature meter is prepared for operation by placing a test solution in the test cell 102, adding and suspending fine crystals of the solute in the solution to obtain a test specimen, mounting the test cell 102 containing the test ~ -specimen on the cell mount 103 and placing the heating unit 100 on top of the light-receiving unit 106. At this point, a space 108 is formed between a heat retaining glass 107 disposed in the lower port.ion of the light-receiving unit 106 and the test cell 102.
With the meter so preparedl light indicated by arrow 109 is admitted via the light path 1()4 upwardly towards the lower end of the test cell 102; and a heater 110 is switched on to effect gradual indirect heating of the test specimen in ` ; the test celL 102~ As the heating is continued, the temperature ~
20 of the test specimen increases and eventually reaches a point ~.
at which the fine crystals in the test specimen are dissolved. ~ ~:
:: :
: At this point, the light penetrating through the test cell 102 .
increases because the scattering of light is decreased on dissolution of the fine crystals and, consequently, a relatively :
large change occurs in the amount of light being continuously received by the light-receiving (photoelectric) element 105~ ~;
This change manifests itself in the amount of electric current generated by photoelectric conversion in the photoelectric element 105. The temperature of the test specimen is continuously measured by a temperature measuring unit 111 which ~' ~L~L5~276 is held in contact with the lower surface of the -test cell 102.
This temperature meter, therefore, indicates the saturation temperature of the solution under test with reference to the aforementioned change in current generation and the corres-ponding -temperature of the test specimen.
In a conventional saturation temperature meter such as described above, during the elevation of the temperature of the test specimen, the test specimen in the test cell 102 and gas in the space 108 thermally expand. Consequently, an increased portion of the gas and a small volume of steam issuing from the surface of the test specimen leak into and fill the space 108, giving rise to a state of stearn saturation.
In this case, the relation between the temperature of the test cell 102 (Tl) and that of the heat retaining glass 107 (T2) is Tl > T2 under normal working conditions. Consequently, part of the steam filling the space 108 comes into contact with the surface of the heat retaining glass 107 and forms dew-condensa-tion thereon.
~: Experience shows that where the temperature (T2~ is in : 20 the range of from 5 to 10 C, dew-condensation occurs when the temperature diference (Tl - T2) is about 0.2C; and that when the temperature (T2) falls within the range of from 25 to 30C, dew-condensation ensues when the temperature difference (Tl-T2) is about 1 C.
When dew-condensation forms as described above, it causes scattering of the liyht penetrating through the test cell 102 to impair the accuracy of determination. If the heating rate is lowered enough to preclude dew-condensation, the rate must be significantly reduced such that the determination 30 requires an excessively long time, the change in the intensity ~S~;~`76 of the penetrating light occurs very slowly and the saturation point determined is imprecise.
Further, with the conventional saturation temperature meter9 the test specimen is prepared by suspending fine crystals of the solute in the solution under test. Where the .
solution under test is very pure or where the solution is highly supersaturated the initial crystallization (occurrence of pseudocrystals) either during or after the preparation of the test specimen proceeds very quickly so that the determination demands a high degree of skill or the reproducibility of the determined values is impaired.
With reference to Figs. 1, 2, 3 and 5-a, 1 denotes a warmer which is generally constructed in a cylindrical form from a metal such as cast aluminum which excels in thermal conduc-tivity. Inside the warmer 1, a heat generator 2 i5 buried and ; used for elevating the temperature o:E the warmer 1 to a desired level. The heat generator 2 can be, for example, an electric heating coil capable of being adjusted to a desired temperature.
; The warmer 1, at the center thereof, contains a vertical cylindrical opening to form a light path 3. The light path 3 is so disposed that the light from a light source 4 positioned under the light path 3 is collecte~ by a lens 5 and passed :.
upwardly through the light path 3. Inside the warmer 1, in the upper part of the light path 3, a mounting base 6 is formed for supporting an air seal glass 7 concentrically relative to the light path 3. This mounting base 6, which serves as a mounting base for the air seal glass 7, has a diameter greater than the diameter of the light path 3. The mounting base 6 supports the air seal glass 7 perpendicular to the light path 3. At a prescribed distance below the moun-ting base 6 for the air seal z~
glass 7, a mounting base 8 for supporting a test cell 9 is concentrically formed rela-tive to -the mounting base 6. This mounting base 8, which serves as a mounting base for the test cell 9, maintains the test cell 9 parallel to the air seal glass 7. l'he distance between the mounting base 6 for the air seal glass 7 and the mounting base 8 for the test cell 9 is so fixed that, when the test cell 9 and the air seal glass 7 are set fast in position on the respective mounting bases 6 and 8, a space 10 within the range of from 0.5 mm to several ~m is formed between the cell 9 and the air seal glass 7. The space 10 is a substantially closed space which is enclosed by the air seal glass 7, the test cell 9 and the inner wall of the warmer 1.
Air ducts 11 fvrmed through the warmer 1 communicate with respective ends of space 10, to permit flow of air through the air ducts 11 and the s~ace 10 in the direction of the arrows.
The test cell 9 is, therefore, heated on both sides, i.e. on its lower side by the heat received clirectly from the warmer 1 ; and on its upper side by the heat from the circulating air which has been heated by the warmer 1.
The test cell 9 is generally formed by inserting a washer 13 made of a corrosion-proof, highly thermoconductive metal such as, for example, brass between two clrcular glass plates 12 and 12' disposed as illustrated in Fig. 5-a. The lower glass plate 12' is joined fast to the washer 13, and the upper glass plate 12 is separably mounted on the washer 13. Thus~
the test cell 9 contains a space for accommodating a test specimen between the opposed glass plates 12 and 12'. A
temperature-measuring terminal 14 is disposed in a position such that it will come into contact with the lower glass plate 12' when the test cell 9 is mounted in position on the mounting base 8 for the test cell 9. Generally, a precision grade thermocouple is used as the temperature-measuring -terminal 14.
Instead of using a construc-tion incorporating a washer as described above, the test cell may be formed by simply combining two transparent glass plates.
Denoted by 15 is a light-receiving unit, which is removably mounted on top of the warmer 1. The light-receivi.ng unit 15 is preferably composed of two different rnaterials; a base 16 made of a heat-resistant synthetic resin of low thermal conductivity and adapted to come into direct contact with the warmer 1 and a member 17 disposed on the base 1~ and adapted to support a photoelectric element 21. To ensure complete dissipation of the heat transmi.tted from -the base 16, in order to protect the photoelectric element 21 from possible temperature elevation, the member 17 is preferably made of a material of high thermal conductivity. Copper i'3 an ideal example of the material for the member 17. By 16' are denoted legs projecting from the lower side of the base 16. These legs 16l serve to form a space between the warmer 1 and the base 1~ and, thereby, form adiabatic insulation. Denoted by 18 is a light path, leading to the light-receiving unit, which is formed coaxially with the light path 3. A heat retaining glass 1~ is disposed below the light path 18 for the light-receiving unit 15. Light which passes through the heat retaining glass 19 projects through a polarizing lens 20 onto the photoelectric element 21.
The photoelectric element 21 is formed of a photosensi.tive matexial such as a photodiode. To support this element 21, a rising portion 22 is formed at the central upper portion of the member 17. Held in a fixed position at all times, the photo-electric element 21 detects the amount of light received via the ~;
"~ .
`7~;
light-receiving path 18. The light which impinges upon this photoelectric element 21 is converted into an electric current An output terminal 23 is connected to the photoelectric element 21. This terminal is ex-tended and connected to a recorder or measuring instrument which is not illustrated.
Now, the operation of the above-described apparatus for the determination of satuxation temperature will be described.
The apparatus is prepared for operation by, ~irst, suspending in a solvent fine crystals of the solute dissolved in a test solution; pouring the resulting suspension dropwise onto the light-penetrating bottom face of the test cell 9;
subsequently vaporizing the solvent by suitable means such as heating, thereby causing the fine crystals of the solute to be firmly deposited in the forrn of a thin layer S on the light-penetrating face as illustrated in Fig. 5-b.
The solvent used should be inert to the solute and should vaporize at an appropriate rate. Where sucrose is used as the solute, for example, acetone proves to be a suitable solvent and brings about a satisfactorily fast deposition o~ the solute. However, in this case, ether vapori~es too rapidly and alcohol vapori~es too slowly to allow the desired fast deposition of the solute. Of course, a mixture of solvents can also be used.
Into the test cell 9, in which the fine crystals have been firmly deposited in the form of a thin layer S as described above, the test solution is slowly poured to cover the upper glass plate 12, completing the preparation of a test specimen.
The test cell 9 containing the test specimen as described above is set in position on the mounting base 8 ~5~Z~
illustrated in Fig. 1. Above the test cell 9, the air seal glass 7 is se-t in position on the mounting base 6. Preparation of the apparatus for the determina-tion is then comp]eted by moun~ing the light-receiving unit 15 on the warmer 1. Then, air circulation through the air duct 11 is started and the heat generator 2 and the light source 4 are switched on.
After 100 parts of light (representing a given incident intensity) have entered the test specimen layer A
(Fig. 1), some part of the light is absorbed by the solution and cell and some part thereof is randomly scattered by the fine crystals forming the thin layer S. Consequently, less than 100 parts of the light penetrates through the cell ~ and reaches the photoelectric element 21, there to be converted into a corresonding amount of electric current.
Proportionally, as the temperature of the test specim~n increases, the amount of light absorbed by the solution increases, hence the light reaching the photoelectric element 21 decreases and the current generated decreases. The curve plotting the current recorded continuously (as a function in mV) with time indicates that the current decreases with the lapse of time (Fig. 6).
As the heating continue~ to a point where the fine crystals forming the thin layer S begin to dissolve, i.e. where the saturation temperature is just passed, the scattering of -the light begins to decrease owing to the decrease in the amount of the fine crystals and the amount of light reaching the photo-electric element 21 suddenly changes to an increasing trend.
Consequently, a point of inflection appears in the curve plotting the continuous change of current generated. The temperature which corresponds to this point of inElection is the saturation temperature of the solution under test. By com~ining the afore-mentioned point of inflection and the temperature of -the test specimen indicated on the temperature-measuring terminal 14, therefore, the sa-turation temperature can be readily determined, as shown in Fig. 6.
The test specimen to be used for the determination as described above is prepared without entailing the step of causing fine crystals of the solute to be suspended in the solution under test as practised conventionally. Thus, the occurrence of pseudocrystals during or after the preparation of the test specimen is precluded and, consequently, the determination affords accurate results.
Further, as described above, air which has been warmed by the warmer 1 is blown into the space 10 formed by the tes-t cell 9. The surface temperature of the air seal glass 7 defininy the upper boundary oE space 10, therefore, is substan-tially equal to the temperature of the test cell 9. Therefore, steam leaking from the cell 9 due to thermal expansion thereof does no~ form dew-condensation in the space 10 as experienced with conventional apparatus. Since the leaking steam is constantly purged out of the space 10 by the current of air flowing through the air duct 11, no steam stagnates anywhere within the space 10.
The improvements noted above serve to expedite the determination and, at the same time, greatly enhance the reproducibility of the results obtained.
For the purpose of comparison, the method and apparatus described herein and those of the conventional techni~ue were used to determine the saturation temperature of a sucrose solution. The resul-ts were as shown in Table 1. Comparison ~1' ~5~2`~i of the precision of determinal_ion,: expressed in terms of standard deviation (S.D.) of the measured values, reveals that the S.D. of the results obtained by -the method described herein was relatively small and the average value agreed closely with the theoretical value.
The procedure for tl~e determination and the results of the determination (Table 1) are explained below:
This invention - the procedure followed for the preparation of .
the apparatus (as shown in Fig. 1) comprised suspending in acetone a small amount of suc:rose crystals pulverized in ad~ance to a particle size of not more than 200 mesh; pouring the resultant suspension dropwise and gradually onto the light-penetrating bottom surface (glass plate 12') of the test cell 9 mounted on a hot plate heated to from 80 to 100C; allowing the fine crystals to form an apparently uniform thin layer;
vaporizing the acetone thereby causing the thin layer of fine crystals to be firmly deposited on the glass plate and, on completion of the deposition of the fine crystals, allowing the : test cell 9 to cool; gently pouring into the test cell 9 a sucrose solution having a pur:ity of 99% and a total solids content o~ 75% (w/w); and covering the test cell 9 with a cover ~glass plate 12). Then, by following the procedure described above, determining the saturation temperature by heating the test specimen at rate of 5 C/minute.
Conventional techni~ue - a test specimen was prepared by gently stirring about 5 y of a sucrose solution having the same purity and concentration as mentioned above with 1 to 2~
W/V, based on the sucrose solution, of a more or less ~et powder sucrose obtained by ce:ntrifuging sucrose crystals of a particle size not exceeding 200 mesh in an alcohol, thereby _ 12 -~j ~
2`~
causlng the sucrose crystals to be suspended in the sucrose solution. This test specimen was poured in~the test cell 9 and the determination of saturation temperature was effected as described above.
TABLE
. ~ Test ~
~ethod \ 1 2 3 4 5 Average S.D.
__ _ ~ _ rhis invention 63.1 63.9 64.2 63.4 63.6 63~64c + 0.38C
~onventional technique 60.2 63.2 62.0 58.5 61.3 61~04C¦ + 1.6C
' ' ,:.
For the sucrose solution tested which had a concen- ;~
tration of 75~, the theoretical value of the saturation tempera ture is 64C (as reported by Her~feld).
As a simple measure for effecting fast deposition of a thin layer S of fine crystals of the solute on the light-penetrating bottom surface of the test cell 9, the aforementioned technique using the vaporization of the solvent may be substltuted by a technique of fastening an adhesive tape to the -;
light-penetratlng bottom surface and allowing the fine crystals :~
of the solute to be laid firmly at a small thickness on the tacky inner side of the adhesive tape; or by a technique of applying a non-drying paste to the light-penetrating bottom surface and similarly firmly depositing the fine crystals on the ~-layer of paste, for example. ~:
Although the technique using the adhesive tape results in slightly less precise results than the other two techniques described above, the decrease in precision is not so large as to pose any problem from the practical point of view.
; . : .
Z~76 The technique using the non-drying paste affords results which compare favourably with those obtained by the technique using -the vaporization of the solvent, when the selection of the paste is appropriate.
In the comparative experiment described above, acetone was used as the solvent. This does not mean that acetone is the sole choice as the solvent. Depending on the nature of the solute in use, other suitable solvents may be selected by taking into account the heating temperature of the test cell 9 and the velocity of vaporization of the solvent.
Optionally, the device for circulating the preheated air through the air duct 11 may be substituted by a device which is adapted to preheat the air with a separate unit; a device which directly feeds air preheated with an external, adjustable heat source to the space 10 and discharges the spent air from the space 10; or any other device which fulfills the essential requirement that air with an adjusted ~emperature should be delivered to and discharged ~rom the space 10 at a fixed flow rate.
The ease with which the test cell 9 is inserted into and removed frorn the apparatus may be enhanced by having a smaller diameter for the upper glass 12 than for the lower glass 12' as illustrated in Fig. 5-c, and -d;and boring a small pickup hole 24 at an exposed portion of the u~per surface of the washer 13.
The following are examples of this invention.
The apparatus and method described above can, for example, be used in the food and organic or inorganic chemical industries to grow crystals in solutions. In particular, the above described apparatus and method enable the determination _ 14 _ .,~,', of saturation temperature in l~ery pure or supersaturated solutions which has been diff:icult with prior art apparatus and methods.
EXA~LE 1 -The test cell 9 was set on a hot plate at 90C. A
suspension prepared by suspending sucrose powder of a particle size of 200-mesh-through in a concentration of about 1% W/V
in acetone was added dropwise to the test cell 9 and was vaporized to form a very thin, uni~orm layer S deposited ~ir~ly in the test cell 9. AEter the test cell 9 was cooled, a varying test specimen as indicated below was poured into the test cell 9. The test cell 9 was mounted on the mounting base 8 in an apparatus constructed as shown in Fig. 1 to determine the saturation temperature of the test specimen. The apparatus was operated by feeding preheated air to the space 10 thereby elevating the temperature o~ the test specimen at a rate of 3oc/minute -The test specimen was prepared by allowing the molasses produced at the Memuro Plant of Nippon Tensaiseito ~abushikl Kaisha to stand in a refrigerator at 5C for 60 days, adding sucrose to the cooled molasses and keeping the resultant mixture stirredinaconstant temperature bath (controlled accurately to within 0.5C) for 72 hours thereby saturating the mixture with an excess o~ crystalline sugar.
Test specimen A - Bath temperature 60 C, true sucrose purity 56%
Test specimen B - Bath temperature 70 C, true sucrose purity 60%
~55~
'rest results (in C) _ Test 1 2 _ 3 - 4 _ Averaqe _ rest Specimen A 61.2 60.5 60.3 61.6 60.3 60.8 + 0.53 rest Speci~,len B 69.8 69.0 69~0 69.3 70.1 69.4 + 0.41 _ _ _ . I
A double-faced adhesive tape made by 2~ichiban K.K. was applied to accurately cover the inner bottom surface of the test cell 9. Sucrose powder having a particle size of 200-mesh-through was placed on the adhesive tape in the test cell 9 and was blown with air to expel loose sucrose particles and leave behind a very thin layer S of fine crystals firmly deposited in the test cell 9. The same test specimens as used in Example 1 were poured in the test cell 9, and measured by following the procedure of Example 1, with the temperature increasing rate being fixed at 3C/minute.
Test results (in C) _ .
Test 1 2 3 4 5 Average _ _ ~ .
rest specimen A 61.8 61.0 60.959~8 62.6 61.2 + 1.1 _ _ .
~ rest specimen B 71.2 72.1 69.872.0 70.8 71.8 + 0.95 .. __ . _ -- .
.
A non-drying paste produced by Nogawa Chemical K.K.
and marketed under the trade mark designation of DIABOND 605 was applied as a thin layer to the inner bottom surface o~ the test cell 9. Sucrose ~owder having a particle size of 200 mesh-through was placed on the non-drying paste in the test cell 9 and was blown with air to expel loose sucrose particles and leave behind a very thin layer S of fine crystals ~irmly deposited in the test cell 9. SpeCiMenS A and ~ were tested by ~,"
~lS~
following the procedure of Example 1, with the temperature increasing rate being fixed at 3C/minute.
Test results (in C) Test 1 2 3 4 5 Average ~ :
_ .
Test specimen A 60.259.4 61.160.5 60.7 60.4 ~ 0.57 .
Test specimen B 70.169.5 69.069.8 70.5 69.8 + 0.51 , ._
causlng the sucrose crystals to be suspended in the sucrose solution. This test specimen was poured in~the test cell 9 and the determination of saturation temperature was effected as described above.
TABLE
. ~ Test ~
~ethod \ 1 2 3 4 5 Average S.D.
__ _ ~ _ rhis invention 63.1 63.9 64.2 63.4 63.6 63~64c + 0.38C
~onventional technique 60.2 63.2 62.0 58.5 61.3 61~04C¦ + 1.6C
' ' ,:.
For the sucrose solution tested which had a concen- ;~
tration of 75~, the theoretical value of the saturation tempera ture is 64C (as reported by Her~feld).
As a simple measure for effecting fast deposition of a thin layer S of fine crystals of the solute on the light-penetrating bottom surface of the test cell 9, the aforementioned technique using the vaporization of the solvent may be substltuted by a technique of fastening an adhesive tape to the -;
light-penetratlng bottom surface and allowing the fine crystals :~
of the solute to be laid firmly at a small thickness on the tacky inner side of the adhesive tape; or by a technique of applying a non-drying paste to the light-penetrating bottom surface and similarly firmly depositing the fine crystals on the ~-layer of paste, for example. ~:
Although the technique using the adhesive tape results in slightly less precise results than the other two techniques described above, the decrease in precision is not so large as to pose any problem from the practical point of view.
; . : .
Z~76 The technique using the non-drying paste affords results which compare favourably with those obtained by the technique using -the vaporization of the solvent, when the selection of the paste is appropriate.
In the comparative experiment described above, acetone was used as the solvent. This does not mean that acetone is the sole choice as the solvent. Depending on the nature of the solute in use, other suitable solvents may be selected by taking into account the heating temperature of the test cell 9 and the velocity of vaporization of the solvent.
Optionally, the device for circulating the preheated air through the air duct 11 may be substituted by a device which is adapted to preheat the air with a separate unit; a device which directly feeds air preheated with an external, adjustable heat source to the space 10 and discharges the spent air from the space 10; or any other device which fulfills the essential requirement that air with an adjusted ~emperature should be delivered to and discharged ~rom the space 10 at a fixed flow rate.
The ease with which the test cell 9 is inserted into and removed frorn the apparatus may be enhanced by having a smaller diameter for the upper glass 12 than for the lower glass 12' as illustrated in Fig. 5-c, and -d;and boring a small pickup hole 24 at an exposed portion of the u~per surface of the washer 13.
The following are examples of this invention.
The apparatus and method described above can, for example, be used in the food and organic or inorganic chemical industries to grow crystals in solutions. In particular, the above described apparatus and method enable the determination _ 14 _ .,~,', of saturation temperature in l~ery pure or supersaturated solutions which has been diff:icult with prior art apparatus and methods.
EXA~LE 1 -The test cell 9 was set on a hot plate at 90C. A
suspension prepared by suspending sucrose powder of a particle size of 200-mesh-through in a concentration of about 1% W/V
in acetone was added dropwise to the test cell 9 and was vaporized to form a very thin, uni~orm layer S deposited ~ir~ly in the test cell 9. AEter the test cell 9 was cooled, a varying test specimen as indicated below was poured into the test cell 9. The test cell 9 was mounted on the mounting base 8 in an apparatus constructed as shown in Fig. 1 to determine the saturation temperature of the test specimen. The apparatus was operated by feeding preheated air to the space 10 thereby elevating the temperature o~ the test specimen at a rate of 3oc/minute -The test specimen was prepared by allowing the molasses produced at the Memuro Plant of Nippon Tensaiseito ~abushikl Kaisha to stand in a refrigerator at 5C for 60 days, adding sucrose to the cooled molasses and keeping the resultant mixture stirredinaconstant temperature bath (controlled accurately to within 0.5C) for 72 hours thereby saturating the mixture with an excess o~ crystalline sugar.
Test specimen A - Bath temperature 60 C, true sucrose purity 56%
Test specimen B - Bath temperature 70 C, true sucrose purity 60%
~55~
'rest results (in C) _ Test 1 2 _ 3 - 4 _ Averaqe _ rest Specimen A 61.2 60.5 60.3 61.6 60.3 60.8 + 0.53 rest Speci~,len B 69.8 69.0 69~0 69.3 70.1 69.4 + 0.41 _ _ _ . I
A double-faced adhesive tape made by 2~ichiban K.K. was applied to accurately cover the inner bottom surface of the test cell 9. Sucrose powder having a particle size of 200-mesh-through was placed on the adhesive tape in the test cell 9 and was blown with air to expel loose sucrose particles and leave behind a very thin layer S of fine crystals firmly deposited in the test cell 9. The same test specimens as used in Example 1 were poured in the test cell 9, and measured by following the procedure of Example 1, with the temperature increasing rate being fixed at 3C/minute.
Test results (in C) _ .
Test 1 2 3 4 5 Average _ _ ~ .
rest specimen A 61.8 61.0 60.959~8 62.6 61.2 + 1.1 _ _ .
~ rest specimen B 71.2 72.1 69.872.0 70.8 71.8 + 0.95 .. __ . _ -- .
.
A non-drying paste produced by Nogawa Chemical K.K.
and marketed under the trade mark designation of DIABOND 605 was applied as a thin layer to the inner bottom surface o~ the test cell 9. Sucrose ~owder having a particle size of 200 mesh-through was placed on the non-drying paste in the test cell 9 and was blown with air to expel loose sucrose particles and leave behind a very thin layer S of fine crystals ~irmly deposited in the test cell 9. SpeCiMenS A and ~ were tested by ~,"
~lS~
following the procedure of Example 1, with the temperature increasing rate being fixed at 3C/minute.
Test results (in C) Test 1 2 3 4 5 Average ~ :
_ .
Test specimen A 60.259.4 61.160.5 60.7 60.4 ~ 0.57 .
Test specimen B 70.169.5 69.069.8 70.5 69.8 + 0.51 , ._
Claims (6)
1. A method for the optical determination of the saturation temperature of a given substance in a solution subject to test by a procedure involving the steps of placing the solution in a test cell, suspending therein fine crystals of the solute dissolved in the solution thereby preparing a test specimen, mounting the test cell now containing the test specimen on a mounting base formed in a temperature-adjustable heater, gradually elevating the temperature of the test specimen and throwing a light upwardly at the test specimen, receiving the light penetrating through the test specimen on a photo-electric element and calculating the saturation temperature based on the temperature of the test specimen and the amount of electricity generated in the photoelectric element, which method is characterized by causing the fine crystals of the solute to be deposited fast in the form of a thin layer on the light-penetrating surface of the test cell and then pour-ing said solution on the deposited thin layer to prepare a test specimen, mounting the test cell containing the test specimen on said mounting base, gradually elevating the tem-perature of the test specimen and throwing light upwardly at the test specimen, at that time an empty space on the cell is made as a closed empty space and preheated air is passed through the closed empty space.
2. The method according to claim 1, wherein said fast deposition of said fine crystals in a thin layer is ac-complished by suspending the fine crystals of the solute in the solvent, dropping the suspension onto the light-penetra-ting face of the test cell and subsequently vaporizing the solvent.
3. The method according to claim 1, wherein said fast deposition of said fine crystals is effected by fasten-ing an adhesive tape to the light-penetrating face of the test cell and causing the fine crystals to be fast deposited on the adhesive tape.
4. The method according to claim 1, wherein said fast deposition of said fine crystals is effected by applying an adhesive agent to the light-penetrating face of the test cell and causing the fine crystals to be fast deposited on the layer of the adhesive agent.
5. An apparatus for optical determination of the saturation temperature of a given substance dissolved in a solution under test comprising:
a light source;
a light receiving unit above said light source, and having a light receiving element and a first light path therein;
a warmer positioned between said light source and said light receiving unit, said warmer having a second light path therethrough;
a test cell supported by said warmer and extending through said second light path;
an air seal glass supported by said warmer, said air seal glass being positioned above said test cell and ex-tending through said second light path such that the distance between the test cell and the air seal glass is betweem 0.5 mm and several mm;
said warmer being capable of warming said test cell;
whereby light emitted from said light source passes through said second light path, said test cell, said air seal glass and said first light path, and is received by said light receiving element so as to optically determine the saturation temperature;
the test cell, warmer and air seal glass forming a substantially closed space;
air ducts pierced through said warmer and communicated with said closed space; and means to introduce a drying fluid to said closed space through said air ducts.
a light source;
a light receiving unit above said light source, and having a light receiving element and a first light path therein;
a warmer positioned between said light source and said light receiving unit, said warmer having a second light path therethrough;
a test cell supported by said warmer and extending through said second light path;
an air seal glass supported by said warmer, said air seal glass being positioned above said test cell and ex-tending through said second light path such that the distance between the test cell and the air seal glass is betweem 0.5 mm and several mm;
said warmer being capable of warming said test cell;
whereby light emitted from said light source passes through said second light path, said test cell, said air seal glass and said first light path, and is received by said light receiving element so as to optically determine the saturation temperature;
the test cell, warmer and air seal glass forming a substantially closed space;
air ducts pierced through said warmer and communicated with said closed space; and means to introduce a drying fluid to said closed space through said air ducts.
6. A device for the optical determination of a saturation temperature as in claim 5, wherein means are provided on the lower side of said light receiving unit to create an empty space between the lower portion of said light receiving unit and the upper portion of said warmer when said light receiving unit is mounted on said warmer during use.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55-17819 | 1980-02-18 | ||
| JP1781980A JPS6057019B2 (en) | 1980-02-18 | 1980-02-18 | Method for preparing samples for saturation temperature measurement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1159276A true CA1159276A (en) | 1983-12-27 |
Family
ID=11954333
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000370151A Expired CA1159276A (en) | 1980-02-18 | 1981-02-05 | Method for optical determination of saturation temperature and apparatus therefor |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS6057019B2 (en) |
| BE (1) | BE887462A (en) |
| CA (1) | CA1159276A (en) |
| DE (2) | DE3153477C2 (en) |
| DK (1) | DK157157C (en) |
| FR (1) | FR2476316A1 (en) |
| GB (1) | GB2072845B (en) |
| NL (1) | NL8100810A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8203013A (en) * | 1982-07-28 | 1984-02-16 | Unie Van Kunstmestfab Bv | METHOD AND APPARATUS FOR DETERMINING THE SATURATION TEMPERATURE OF A SOLUTION |
| US5222390A (en) * | 1991-09-20 | 1993-06-29 | The Dow Chemical Company | Crystallization analysis fractionization |
| CN108489629B (en) * | 2018-06-20 | 2024-01-05 | 山东大学 | Automatic measuring device and measuring method for solution saturation temperature |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2716371A (en) * | 1950-05-22 | 1955-08-30 | Gen Electric Co Ltd | Apparatus for measuring the saturation temperature of solutions |
| US2896854A (en) * | 1956-07-10 | 1959-07-28 | Electric Eye Equipment Company | Protecting device for window of optical housing |
| FR1366114A (en) * | 1963-05-28 | 1964-07-10 | Commissariat Energie Atomique | Heating plate |
| CH451550A (en) * | 1967-06-12 | 1968-05-15 | Mepag Ag | Heating table for thermo-microscopic examinations |
-
1980
- 1980-02-18 JP JP1781980A patent/JPS6057019B2/en not_active Expired
-
1981
- 1981-02-05 CA CA000370151A patent/CA1159276A/en not_active Expired
- 1981-02-11 BE BE0/203756A patent/BE887462A/en not_active IP Right Cessation
- 1981-02-17 GB GB8104913A patent/GB2072845B/en not_active Expired
- 1981-02-18 DE DE19813153477 patent/DE3153477C2/de not_active Expired - Fee Related
- 1981-02-18 FR FR8103163A patent/FR2476316A1/en active Granted
- 1981-02-18 DK DK71881A patent/DK157157C/en not_active IP Right Cessation
- 1981-02-18 DE DE19813105969 patent/DE3105969A1/en active Granted
- 1981-02-18 NL NL8100810A patent/NL8100810A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| DE3153477C2 (en) | 1990-05-03 |
| FR2476316A1 (en) | 1981-08-21 |
| GB2072845A (en) | 1981-10-07 |
| DK71881A (en) | 1981-08-19 |
| DK157157B (en) | 1989-11-13 |
| FR2476316B1 (en) | 1984-12-21 |
| DE3105969C2 (en) | 1989-08-31 |
| DE3105969A1 (en) | 1981-12-24 |
| GB2072845B (en) | 1983-07-27 |
| JPS6057019B2 (en) | 1985-12-12 |
| BE887462A (en) | 1981-06-01 |
| JPS56115946A (en) | 1981-09-11 |
| DK157157C (en) | 1990-04-16 |
| NL8100810A (en) | 1981-09-16 |
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