GB2072845A - Method and apparatus for determining the saturation temperature of a solute in a solution - Google Patents
Method and apparatus for determining the saturation temperature of a solute in a solution Download PDFInfo
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- GB2072845A GB2072845A GB8104913A GB8104913A GB2072845A GB 2072845 A GB2072845 A GB 2072845A GB 8104913 A GB8104913 A GB 8104913A GB 8104913 A GB8104913 A GB 8104913A GB 2072845 A GB2072845 A GB 2072845A
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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
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- 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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- Investigating Or Analysing Materials By Optical Means (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
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Abstract
A test cell 9 contains a specimen of the solution to be tested which is poured over a thin layer (S, Figure 5-b) of fine crystals of the solute deposited on a light-transmitting surface (12%) thereof. As the test cell 9 is heated by a warmer 1, the amount of crystals in the thin layer alters according to the quantity of solute dissolved in the solution, thereby varying the amount of light from a source 4 which is transmitted through the test cell 9 to a detector 21. The saturation temperature can be determined from the output signal of the detector 21 and the temperature of the test cell 9 as measured by a thermocouple 14. The detector 21 forms part of a light- receiving unit 15 which is detachably mounted on top of the warmer 1, and the warmer 1 includes an air seal glass 7 adjacent the unit 15. In order to prevent evaporated solution condensing in a closed space 10 between the glass 7 and the test cell 9, which would otherwise adversely affect the measurements, a continuous stream of pre-heated air is passed through the space 10 by means of ducts 11. <IMAGE>
Description
SPECIFICATION
Method and apparatus for determining the saturation temperature of a solute in a solution
This invention relates to a method of and apparatus for optically determining the saturation
temperature of a solute in a solution.
A saturation temperature meter is an instrument which is necessary when in the organic chemical,
inorganic chemical and food industries the saturation temperatures of various substances are to be
determined for the purpose of scientific management of crystals during the eduction of crystals in
solutions. No measure is known to date for providing effective determination of the saturation temperature.
Recently, an improved saturation temperature meter designed for optical determination of
saturation temperature has been reported in the International Sugar Journal, Vol. LXXX, 1 978 pp 40-43 (published at 23a Easton Street, High Wycombe, Bucks, England). This saturation temperature
meter is shown in sectional side view in Figure 4 of the accompanying drawings, and comprises
generally a light source 101, a heating unit 100 provided with a light passage 104 and a mount 103 for
a test cell 102, and a light-receiving unit 106 including a light-sensitive (photoelectric) element 105.
The temperature meter is prepared for operation by placing the solution subject to test in the test cell
1 02 and adding fine crystals of the solute dissolved in the solution so that these are suspended in the
solution. The test cell 102 containing the resultant test specimen is then mounted on the cell mount
1 03, and the heating unit 1 00 is placed on top of the light-receiving unit 1 06. At this point, an air space
108 occurs between the test cell 102 and a heat-retaining glass 107 disposed in the lower portion of
the light-receiving unit 106.
With the meter so prepared, light 109 is admitted via the light passage 104 upwardly from 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 of the test specimen
increases and eventually reaches a point at which the fine crystals in the test specimen are dissolved. At
this point, a change occurs in the light transmitted through the test cell 102 (the amount of transmitted
light increases because scattering is decreased when the fine crystals dissolve), and consequently a
large change occurs in the amount of light received by the light-sensitive element 105. This change
manifests itself in a change in level of the output signal from the light-sensitive element 105.In the
meantime, the temperature of the test specimen is continuously measured by a temperature measuring
unit 111 which is held in contact with the lower surface of the test cell 102. This temperature meter,
therefore, enables the saturation temperature of the solution under test to be determined from the point
at which the aforementioned change occurs in the output signal of the element 105 and the
temperature of the test specimen at that point.
In the conventional saturation temperature meter described above, during the elevation of the
temperature of the test specimen, the test specimen in the test cell 102 and the gas in the space 108
gain in volume due to thermal expansion. 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 out the empty space
108, giving rise to a state of steam saturation. In this case, the relation between the temperature of the
test cell 102 (T,) and that of the heat retaining glass 107 (T2) is T, > T2 under normal working
conditions. Consequently, when steam filling the empty space 108 comes into contact with the surface
of the heat retaining glass 107, it forms dew-condensation thereon.The present inventors' experience
tells that where the temperature (T2) is in the range of from 50 to 1 OOC, such dew-condensation occurs
when the temperature difference (T1-T2) is about 0.2"C, and that even when the temperature (T2) falls
within the range of from 250 to 300C, the formation of dew-condensation ensues when the
temperature difference (T1-T2) is about 1 OC. When the dew-condensation forms as described above, it
causes scattering of the light transmitted by the test cell 102 and therefore impairs the accuracy of the
determination.If the rate of heating is reduced sufficiently to preclude dew-condensation formation, the
determination will require an excessively long time, and changes in the amount of light transmitted by
the test cell 102 will occur very slowly so that the saturation point appears very vaguely.
Also in the conventional saturation temperature meter, the test specimen is prepared by
suspending added fine crystals of the solute in the solution under test. In cases where the solution under
test has high purity or where the solution involves a high degree of supersaturation, initial cyrstallisation (occurrence of pseudocrystals) either during or after the preparation of the test specimen proceeds very
quickly so that great skill is required to determine the saturation temperature accurately and
reproducability of the result thus determined is impaired.
it is an object of the present invention to obviate or mitigate the above-described problems and
disadvantages.
According to one aspect of the present invention, there is provided a method of determining the
saturation temperature of a solute in a solution, comprising the steps of depositing a thin layer of fine
crystals of the solute fast on a light-transmitting surface of a test cell, pouring said solution into the test
cell and onto said thin layer of fine crystals, gradually elevating the temperature of the test cell to alter
the amount of solute dissolved in the solution, and measuring the amount of light transmitted through
said thin layer of fine crystals as a function of the temperature of the solution. A test specimen prepared in this manner enjoys stability both during and after the preparation thereof.
According to a second aspect of the present invention, there is provided apparatus for determining the saturation temperature of a solute in a solution, comprising a base which receives a test cell containing a test sample of the solute and solution, a warmer operable gradually to elevate the temperature of the test cell, a passage in the base through which light is passed for transmission through the test cell, a light-transmitting member sealingly mounted on the base such that said light passes therethrough after transmission by the test cell, a space being defined between the lighttransmitting member and the test cell, a light-receiving unit detachably mounted on the base and including a light-sensitive detector which receives the light passing through the light-transmitting member and which measures the amount of light transmitted by the test cell, and means providing continuous passage of gas through said space between the light-transmitting member and the test cell to prevent vapourised solution from the test cell condensing on the light-transmitting member.
In this way, external disturbance of the results of the determination can be precluded and the time required for the determination can be reduced. Moreover, the invention provides easy determination of the saturation temperature even in the case of solutions which behave unstably at high degrees of purity or supersaturation: previously, such determination has been either totally impracticable or possible only with very deliberate and skillful techniques. The invention can therefore be utilized advantageously for the routine control of crystallisation operations, such as those involved in the chemical and food industries.
The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a sectional side view of apparatus according to the present invention;
Figure 2 is a partial section taken along the line Il-Il in Figure 1;
Figure 3 is an exploded sectional side view of parts of the apparatus shown in Figure 1;
Figure 4 is a sectional view of prior art apparatus for determining the saturation temperature of a
solute in a solution, as has been described hereinbefore;
Figure 5-a is a sectional side view of a test cell for use in the apparatus shown in Figure 1;
Figure 5-b shows one stage in the preparation of the test cell;
Figure 5-c is a sectional side view of an improved design of test cell;
Figure 5-d is a plan view of the test cell shown in Figure 5-c; and
Figure 6 is a graph showing a characteristic curve produced by the apparatus of Figure 1 and from
which the saturation temperature can be calculated.
Referring first to Figure 1, the illustrated apparatus comprises a warmer 1 of cylindrical shape and
made of a metal having a high thermal conductivity, such as aluminium. A heat generator 2, which is similar to an electric heating coil, is buried inside the warmer 1 and can be adjusted to a desired temperature to elevate the temperature of the warmer 1 to a desired level. At the centre thereof the warmer 1 has a vertical cylindrical opening forming a light passage 3 through which light produced by a
light source 4 and collected by a lens 5 passes upwardly. Inside the warmer 1 adjacent an upper part of
the light passage 3, a mounting base is formed for supporting an air seal glass 7 concentrically relative
to the passage 3.The base 6 has a diameter which is greater than the diameter of the light passage 3
and supports the air seal glass 7 perpendicularly relative to the light passage 3. At a prescribed distance
below the mounting base 6, a mounting base 8 for supporting a test call 9 is concentrically formed
therewith and maintains the test cell 9 parallel to the air seal glass 7. This distance between the
mounting bases 6 and 8 is so fixed that, when the test cell 9 and the air seal glass 7 are set fast in
position on the respective bases, an air space 10 whose thickness is in a range of from 0.5 mm to
several mm is formed between the cell 9 and the glass 7. This 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 pierced
through the warmer 1 communicate with respective ends of the space 10 to permit air to flow
therethrough in the direction of the arrows. The test cell 9 is therefore heated on both sides, i.e. on the
lower side by the heat received directly from the warmer 1 and on the upper side by the heat from the
air passing through the ducts 10 which has been pre-heated by the warmer 1.
The test cell 9 is formed generally by inserting a washer 1 3 made of a corrosion proof, highly
thermoconductive metal, such as brass, between two circular glass plates 12 and 12' disposed as
illustrated in Figure 5-a. The lower glass plate 12' is joined fast to the washer 13, while the upper glass
plate 12 is removably mounted on the washer 3. Thus, the test cell 9 contains an empty space for
admitting a test specimen between the opposed glass plates 12, 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. Generaliy, a precision grade
thermocouple is used as the temperature-measuring terminal 14. Instead of using a construction
incorporating a washer as described above, the test cell may be formed by simply combining two
transparent glasses.
A light-receiving unit 1 5 is freely removably mounted on top of the warmer 1, and is desirably
composed of two components of different materials; a base 1 6 made of a heat-resistant synthetic resin
of low thermal conductivity which comes into direct contact with the warmer 1, and a member 1 7 disposed on the base 1 6 and adapted to support in a position a photoelectric element 21. For the purpose of ensuring thorough release of the heat transmitted from the base 1 6 and preventing the photoelectric element 21 from possible temperature elevation, the member 1 7 is desirably made of a material of high thermal conductivity, copper being an ideal example of such a material.Legs 1 6' project from the lower side of the base 1 6 so that a space is formed between the warmer 1 and the base 16, thereby permitting adiabatic effect insulation. A light passage 1 8 leading through the lightreceiving unit 1 5 formed coaxially with the light passage 3 in the warmer 1, and a heat-retaining glass 1 9 is disposed below the light passage 1 8. Light which has passed through the heat-retaining glass 1 9 is forwarded through a polarizing lens 20 to a light-sensitive element 21 which is formed of a photosensitive material and which may be in the form of a photodiode, for example. To support the element 21 in position, a rising portion 22 is formed at a central upper part of the member 1 7.Held in a fixed position at all times, the light-sensitive element 21 detects the amount of light passing through the light passage 18, and the light which impinges upon the element 21 is converted into an electrical output signal at an output terminal 23 which is connected to a recorder or measuring instrument (not illustrated).
The operation of the apparatus described above will now be explained. First of all, the test cell 9 is prepared by suspending in a liquid fine crystals of a solute, pouring the resultant suspension dropwise onto the light-transmitting bottom face of the test cell 9, and subsequently vapourising the liquid by suitable means such as an application of heat, thereby causing the fine crystals of the solute to be deposited fast in the form of a thin layer S on the light-transmitting bottom face, as illustrated in Figure 5-b. The liquid used here should not affect the solute, i.e. it must not dissolve or react with the latter, and should possess an appropriate speed vapourisation. A liquid satisfying these requirements may be suitably selected by taking into consideration the physical and chemical properties possessed thereby.
For example, in the case where sucrose is used as the solute, acetone proves to be a suitable liquid and brings about rapid deposition of the solute in a satisfactory manner. Ether possesses too high a vapourisation speed while conversely alcohol possesses too low a vapourisation speed to bring about the desired deposition of the solute. Optionally, a mixture of two or more liquids, each fulfilling the requirement for avoiding undesirable alteration of the solute may be used.
Into the test cell 9 in which the fine crystals have been deposited in the form of a thin layer S as described above, the solution under test 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 is set in position on the mounting base 8 as illustrated in Figure 1. Above the test cell 9, the air seal glass 7 is set in position on the mounting base 6. Preparation of the apparatus for the determination is then completed by mounting the light-receiving unit 1 5 on the warmer 1. Then, air is passed through the ducts 11 and the space 10, the heat generator 2 is energised and the light source 4 is switched on to project the light towards the test cell 9.After 100% of the light has entered the test specimen layer A, a part of the light is absorbed by the solution and a part thereof is randomly scattered by the very fine crystals forming the thin layer S.
Consequently, less than 100% of the light is transmitted through the cell 9 to the light-sensitive element 21, where it is converted into a corresponding output signal. In proportion as the temperature of the test specimen increases, the amount of the light absorbed by the solution increases, and therefore the amount of light reaching the light-sensitive element 21 decreases and the output signal produced thereby also decreases. A curve plotting the variation of the output signal with time (Figure 6) indicates that the output signal decreases with the lapse of time.
As the heating further proceeds to a point where the fine crystals forming the thin layer S begin to dissolve, i.e. where the saturation temperature is just passed, 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 lightsensitive element 21 suddenly changes to an increasing trend. Consequently, a point of sharp inflection appears in the curve plotting the output signal from the element 21. The temperature which corresponds to this point of sudden inflection is the saturation temperature of the solution under test.
Therefore, by combining the aforementioned point of inflection and the temperature of the test specimen indicated on the temperature-measuring terminal 14, the saturation temperature can be readily determined, as indicated in Figure 6.
In the method for determining the saturation temperature described above, the test specimen is prepared without entailing the step of causing fine crystals of the solute to be suspended in the solution under test as practiced conventionally. Thus, the occurrence of pseudocrystals during or after the preparation of the test specimen is precluded and, consequently, the determination can afford accurate results. Furthermore, the air which has been warmed by the warmer 1 is blown through the space 10 formed between the test cell 9 and the glass 7. The surface temperature of the air seal glass 7 defining the upper boundary of the space 10, therefore, is substantially equal to the temperature of the test cell 9, and any steam leaking from the cell 9 because of thermal expansion does not form dew-condensation as is experienced with the conventional apparatus. Since the leaking steam is constantly purged out of the space 10 by the current of air flowing through the air ducts 11, no steam is allowed to stagnate anywhere within the space 10. These particular advantages serve to expedite the determination and, at the same time, greatly enhance the reproducibility of the results.
For the purpose of comparison, the method and apparatus of the present invention and those according to conventional techniques were used to determine the saturation temperature of a sucrose solution. The results obtained were as shown in Table 1 below. Comparison of the accuracy of determination expressed in terms of dispersions in the measured values reveals that the dispersions in the results obtained by this invention were small and the average values satisfactorily agreed to the theoretical values. The procedure and results of the determination (Table 1) are explained below.
In the case of this invention, the following procedure was followed in the preparation of the apparatus for the determination. A small amount of sucrose crystals pulverized in advance to a particle size of not more than 200 mesh were suspended in acetone, and the resultant suspension was poured dropwise little by little onto the light-transmitting bottom surface (glass plate 12') of the test cell 9 which was mounted on a hot plate heated to 800 to 1 000C, allowing the fine crystals to form an
apparently uniform thin layer. The acetone was thus vapourised, causing a thin layer of fine crystals to
be fast deposited on the glass plate.On completion of the fast deposition of the fine crystals, the test
cell 9 was allowed to cool, after which a sucrose solution having a plurity of 99% and a total solids
content of 75% (w/w) was poured into the test cell 9, and the test cell 9 was covered with a lid (glass
plate 12'). Then, by following the procedure~described above, determination of the saturation
temperature was carried out by heating the test specimen at a temperature increase rate of 5 C/minute.
In the case of the conventional technique, a test specimen was prepared by gently stirring about
5 g of a sucrose solution having the same purity and concentration as mentioned above with 1 to 2%, based on the sucrose solution, of a more or less wet powder sucrose obtained by centrifuging sucrose
crystals of a particle size of not more than 200 mesh in an alcohol, thereby causing the sucrose crystals
to be suspended in the sucrose solution. This test specimen was poured in the test cell 9 and subjected
to determination of the saturation temperature according to conventional techniques.
TABLE 1
Item 1 2 3 4 5 Average Dispersion Method This invention 63.1 63.9 64.2 63.4 63=6 63.64 C + 0.38-C Conventional technique 60.2 63.2 62.0 58.5 61.3 61.O4C i 1.6C For the sucrose solution to be tested which has a concentration of 75%, the theoretical value of the saturation temperature is 640C (as reported by Herzfeld).
In the above experiment acetone was used as the liquid in which the sucrose crystals were suspended, but this does not mean that acetone is the only choice. Depending on the nature of the solute in use, other suitable liquids may be selected by taking into account the temperature of heating of the test cell 9 and the speed of vapourisation of the liquid.
As a simple measure for effecting fast deposition of a thin layer S of fine crystals of the solute on the light-transmitting bottom surface of the test cell 9, instead of the aforementioned technique involving vapourisation of a liquid, an adhesive tape may be fastened to the light-transmitting bottom surface so that the fine crystals of the solute can be laid fast in a thin layer on the viscous inner side of the adhesive tape. Alternatively, a non-drying paste may be appiied to the light-transmitting bottom surface of the test cell 9 and the fine crystals can be laid fast on the layer of paste, for example.
Although the technique making use of an adhesive tape involves a slightly greater dispersion of the determined values than the techniques involving the vapourisation of a liquid and the application of a non-drying paste, the increase of the dispersion is not so large as to pose any problem from the practical point of view. The technique using the non-drying paste affords determination results which compare favourably with those obtained by the technique involving the vapourisation of a liquid when the selection of the paste is proper.
Optionally, the device for passing the preheated air through the air ducts 11 may be suitably
substituted by a device which is adapted to preheat the air by means of a separate unit, a device which directly feeds the air preheated with an external, adjustable heat source to the space 10 and which discharges the spent air from the space 1 0, or any other device which fulfills the essential requirement that the air with an adjusted temperature should be delivered to and discharged from the space 10 at a fixed flow rate. The ease with which the test cell 9 is inserted into and removed from the apparatus may be enhanced (as indicated in Figure 5-c) by giving a smaller diameter to the upper glass 12 than to the lower glass 1 2' and boring a small pickup hole 24 at an exposed portion of the upper surface of the washer 13.
The following working examples are to illustrate typical embodiments of this invention.
EXAMPLE 1:
A test cell 9 was set at rest on a hot plate having a temperature of 900 C. A suspension prepared by suspending in acetone a sucrose powder having a particle size of 200-mesh-through at a concentration of about 1% was added dropwise to the test cell 9 and was vapourised to form a very thin, uniform layer S deposited fast to the test cell 9. After the test cell 9 had cooled, various test specimens indicated below were poured into the cell 9. The test cell 9 was mounted on the mounting base 8 of the apparatus shown in Figure 1 for determination of saturation temperature. The apparatus was operated by feeding the preheated air to the space 10 thereby elevating the temperature of the test specimen at a rate of 30C/minute.The test specimen was prepared by allowing molasses produced at
Memuro Plant of Nippon Tensaiseito Kabushiki Kaisha to stand in a refrigerator at 50C for 60 days, adding sucrose to the cooled molasses and keeping the resultant mixture stirred in a constant temperature bath (controlled accurately to within 0.50C) for 72 hours thereby saturating the mixture with an excess crystalline sugar.
Test Specimen A - Bath temperature 60"C, true sucrose purity 56%
Test Specimen B - Bath temperature 705C, true sucrose purity 60%
Test Results (in C)
Item 1 2 3 4 5 Average Test Specimen A 61.2 60.5 60.3 61.6 60.3 60.8 + 0,53 Test Specimen A 61.2 60.5 60.3 61.6 60.3 60.8 + 0.53 Test Specimen B 69.8 69.0 69.0 69.3 70.1 69.4 + 0.41 EXAMPLE 2:
A double-faced adhesive tape made by Nichiban K.K. was applied to cover accurately the inner bottom surface of the test cell 9.A surcrose powder having a particle size of 200-mesh-through was placed on the adhesive tape in the test cell 9 and was biown with air to expel loose sucrose particles and leave behind a very thin layer S of fine crystals deposited fast on the test cell 9. The same test specimens as used in Example 1 were poured in the test cell 9, which was then subjected to the test by following the procedure of Example 1, with the temperature increase rate fixed at 30C/minutes.
Test Results (in C)
Item 1 2 3 4 5 Average Test Specimen A 61.8 61.0 60.9 59.8 62.6 61.2 + 1.1 Test Specimen B 71.2 72.1 69.8 72.0 70.8 71.8 + 0.95 l
EXAMPLE 3:
A non-drying paste produced by Nogawa Chemical K.K. and marketed under the trademark designation of Diabond 605 was applied in a thin layer to the inner bottom surface of the test cell 9. A sucrose powder 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 deposited fast on the test cell 9. The same test specimen as used in Example 1 were poured in the test cell 9, which was then subjected to the test by following the procedure of Example 1, with the temperature increase rate fixed at 30C/minute.
Test Results (in ssC)
Item 1 2 3 4 5 Average Test Specimen A 60.2 59.4 61.1 60.5 60.7 60.4 t 0.57 Test Specimen B 70.1 69.5 69.0 69.8 70.5 69.8 t 0.51
Claims (12)
1. A method of determining the saturation temperature of a solute in a solution, comprising the steps of depositing a thin layer of fine crystals of the solute fast on a light-transmitting surface of a test cell, pouring said solution into the test cell and onto said thin layer of fine crystals, gradually elevating the temperature of the test cell to alter the amount of solute dissolved in the solution, and measuring the amount of light-transmitted through said thin layer of fine crystals as a function of the temperature of the solution.
2. A method as claimed in Claim 1, wherein before being measured the light transmitted through said thin layer of crystals also passes through a light-transmitting member which is spaced from the test cell, and further comprising the step of passing gas continuously through the space between the test cell and the light-transmitting member to prevent vapourised solution from the test cell condensing on the light-transmitting member.
3. A method as claimed in Claim 2, wherein the gas is heated prior to passage through said space.
4. A method as claimed in Claim 1, 2 or 3, wherein the deposition of said thin layer of fine crystals is performed by suspending fine crystals of the solute in a liquid, placing the suspension on the lighttransmitting surface of the test cell, and vapourising the liquid.
5. A method as claimed in Claim 1, 2 or 3, wherein adhesive tape is placed on the lighttransmitting surface of the test cell and said thin layer of fine crystals is deposited on the adhesive tape.
6. A method as claimed in Claim 1, 2 or 3, wherein an adhesive agent is placed on the lighttransmitting surface of the test cell and said thin layer of fine crystals is deposited on the adhesive agent.
7. Apparatus for determining the saturation temperature of a solute in a solution, comprising a base which receives a test cell containing a test sample of the solute and solution, a warmer operable gradually to elevate the temperature of the test cell, a passage in the base through which light is passed for transmission through the test cell, a light-transmitting member sealingly mounted on the base such that said light passes therethrough after transmission by the test cell, a space being defined between the light-transmitting member and the test cell, a light-receiving unit detachably mounted on the base and including a iight-sensitive detector which receives the light passing through the light-transmitting member and which measures the amount of light transmitted by the test cell, and means providing continuous passage of gas through said space between the light-transmitting member and the test cell to prevent vapourised solution from the test cell condensing on the light-transmitting member.
8. Apparatus as claimed in Claim 7, wherein said means includes ducts communicating with said space.
9. Apparatus as claimed in Claim 7 or 8, wherein the gas passing through said space is preheated.
1 0. Apparatus as claimed in Claim 9, wherein the gas is pre-heated by said warmer.
11. A method of determining the saturation temperature of a solute in a solution, substantially as hereinbefore described with reference to Figures 1 to 3 and 5-a to 5-d of the accompanying drawings.
12. Apparatus for determining the saturation temperature of a solute in a solution, substantially as hereinbefore described with reference to Figures 1 to 3 and Figures 5-a to 5-d of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1781980A JPS6057019B2 (en) | 1980-02-18 | 1980-02-18 | Method for preparing samples for saturation temperature measurement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2072845A true GB2072845A (en) | 1981-10-07 |
| GB2072845B GB2072845B (en) | 1983-07-27 |
Family
ID=11954333
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8104913A Expired GB2072845B (en) | 1980-02-18 | 1981-02-17 | Method and apparatus for determining the saturation temperature of a solute in a solution |
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 FR FR8103163A patent/FR2476316A1/en active Granted
- 1981-02-18 DE DE19813153477 patent/DE3153477C2/de not_active Expired - Fee Related
- 1981-02-18 DE DE19813105969 patent/DE3105969A1/en active Granted
- 1981-02-18 DK DK71881A patent/DK157157C/en not_active IP Right Cessation
- 1981-02-18 NL NL8100810A patent/NL8100810A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| NL8100810A (en) | 1981-09-16 |
| CA1159276A (en) | 1983-12-27 |
| JPS6057019B2 (en) | 1985-12-12 |
| DE3105969C2 (en) | 1989-08-31 |
| DK71881A (en) | 1981-08-19 |
| GB2072845B (en) | 1983-07-27 |
| BE887462A (en) | 1981-06-01 |
| FR2476316B1 (en) | 1984-12-21 |
| JPS56115946A (en) | 1981-09-11 |
| DK157157C (en) | 1990-04-16 |
| FR2476316A1 (en) | 1981-08-21 |
| DE3153477C2 (en) | 1990-05-03 |
| DK157157B (en) | 1989-11-13 |
| DE3105969A1 (en) | 1981-12-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930217 |