GB2202941A - Melting/freezing point apparatus - Google Patents
Melting/freezing point apparatus Download PDFInfo
- Publication number
- GB2202941A GB2202941A GB08803169A GB8803169A GB2202941A GB 2202941 A GB2202941 A GB 2202941A GB 08803169 A GB08803169 A GB 08803169A GB 8803169 A GB8803169 A GB 8803169A GB 2202941 A GB2202941 A GB 2202941A
- Authority
- GB
- United Kingdom
- Prior art keywords
- melting point
- substance
- detector
- light
- heating block
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- 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
- G01N25/02—Investigating or analyzing materials by the use of thermal means by investigating changes of state or changes of phase; by investigating sintering
- G01N25/04—Investigating or analyzing materials by the use of thermal means by investigating changes of state or changes of phase; by investigating sintering of melting point; of freezing point; of softening point
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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 Analyzing Materials Using Thermal Means (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
Melting/freezing point apparatus (1) includes means (9) for measuring the change in reflected light from the surface of a substance (7) at the melting point. The apparatus (1) includes a heating block (2) adapted to house a sample plate (4), a light source (8) and a light detector (9). The temperature is measured by a thermocouple in aperture (6). The apparatus may form part of an automated process. <IMAGE>
Description
Melting Point Apparatus
This invention relates to a new melting point apparatus.
Conventional melting point apparatus require a small solid sample to be placed in a capillary tube and the capillary tube placed in a heated oil bath. This method has the disadvantage that the apparatus must be continually watched in order to determine the point at which the solid sample becomes molten. In addition, with a sample which is damp it is difficult to place sufficient of the sample in the capillary tube. Apparatus have been designed which attempt to overcome these disadvantages.
The apparatus described in GB 1246303 measures the change in the optical transmittance of a solid sample upon melting. Similarly, apparatus are known which comprise a heated block wherein the solid sample is placed on a microscope slide. The melting point may be observed through a conventional microscope. However, both of these apparatus require light to be transmitted through the sample. They therefore have the disadvantage that they cannot be used on highly coloured samples or samples which darken at or near the melting point.
Surprisingly, we have now found a means for determining the melting point of a solid which overcomes the disadvantages of existing methods.
According to the invention we provide melting point apparatus which includes means for detecting the change in reflected light from the surface of the substance at the melting point.
The apparatus is particularly suited for the determination of melting point, but may also be used for the determination of the freezing point of a liquid.
The apparatus comprises a sample holder which may be located on or adjacent to a heat source, a light source and a light detector. The light source and light detector are aligned so that a substantial amount of the light reflected from the surface of a substance at its melting point falls on the light detector.
The detector may comprise a simple photoelectric cell but we prefer the detector to be a Schmitt detector. The detector may be linked to a visual and/or audio display unit. In addition the apparatus may be operably linked to a computer such that the rate of heating, the recordal and the display of temperatures and the transference of samples may by automated.
According to the invention we also provide a method of determining the melting point of a substance which comprises detecting the change in reflected light from the surface of the substance at the melting point.
The apparatus of the present invention may be adapted to measure the melting point of a plurality of samples eg 3, simultaneously. The adapted apparatus may include a plurality of individual sample holders or a single sample holder capable of holding a plurality of samples. The adapted apparatus may comprise a plurality of light sources but the apparatus may include only a single light source. The number of detectors included in the apparatus will depend upon the number of samples being investigated. The apparatus may therefore be used in the analytical technique which measures mixed melting points.
We further provide an automated method of determining the melting point of a substance which comprises use of apparatus adapted to measure the change in reflected light from the surface of the substance at the melting point operably linked to a computer.
When a computer is used to automate the method of melting point determination, we prefer it to control both the rate of heating, the recordal and the display of the transition temperatures and also the transference of samples.
Any conventional heat source may be used or a light source may by used, eg an infra-red light, to provide heat. We prefer the heat source to comprise a thermally conductive block.
When the apparatus is utilised in freezing point determination any conventional cooling means may be used but we prefer to use a thermally conductive block which may be cooled, eg at one end.
The maximum melting point of a solid substance which may be recorded will depend upon the heat source used but the apparatus may be useful for measuring melting points up to 6000C, preferably 5000C and more preferably 4500C.
The minimum freezing point which may be determined will depend upon the coolant used but the apparatus may be useful for measuring freezing points down to -2000C, preferably -780C, more preferably -3O0C and most preferably OoC.
The melting point may be measured by conventional means, eg by mercury or alcohol thermometer, or preferably by a thermocouple.
The light source may emit light of a number of wavelengths, eg white light, or of a specific wavelength.
The light source may also act as a heat source, eg by emitting infra-red light.
The invention will now be illustrated by way of example only and with reference to the accompanying drawings in which
Figure 1 is a perspective view of a heating block, and
Figure 2 is a sectional view of a heating block taken along the line X-X including a sectional view of the light source and detector.
Referring to Figures 1 and 2, the melting point apparatus (1) comprises a cylindrical heating block (2) provided with a diametric groove (3) adapted to house a rectangular sample plate (4). The sample plate (4) comprises a strip of thermally conductive material provided with a well (5) capable of holding a solid sample (7) of which the melting point is to be determined. The heating block (2) is also provided with a radial aperture (6) at right angles to the diametric groove (3), adapted to house a temperature detector eg a thermocouple, beneath the well (5) of plate (4) during operation.
For the determination of melting point, a light source (8) and a light detector (9) are located adjacent to the heating block (2) and arranged such that light falling on the solid sample (7) is scattered and little or no response is observed by the detector (9). When the sample plate (4) reaches the melting point of the solid sample (7), the sample (7) becomes molten. The change from solid to molten form alters the characteristic of the sample (7) towards light. In particular the surface of the molten sample (7) is reflective towards light. Thus, an increase in the intensity of light is observed at the detector (9). The temperature at this point can be determined by the temperature detector, eg a thermocouple inserted in the aperture (6).
Claims (8)
1. Melting point apparatus which includes means for detecting the change in reflected light from the surface of a substance at the melting point.
2. Apparatus according to Claim 1 in which the light detector is a Schmitt detector.
3. Apparatus according to any one of the preceding claims, in which the detector is linked to a visual and/or audio display unit.
4. Apparatus according to Claim 3, wherein the apparatus is linked to a computer and the determination of melting point is automated.
5. A method of determining the melting point of a substance which comprises detecting the change in reflected light from the surface of a substance at the melting point.
6. An automated method of determining the melting point of a substance, which comprises use of apparatus adapted to measure the change in reflected light from the surface of the substance at the melting point operably linked to a computer.
7. A melting point apparatus comprising a cylindrical heating block provided with a diametric groove adapted to house a rectangular sample plate, the sample plate comprising a strip of thermally conductive material provided with a well capable of holding a solid sample of which the melting point is to be determined, the heating block is also provided with a radial aperture, at right angles to the diametric groove, adapted to house a temperature detector beneath the well of the sample plate during operation, a light source and a light detector are located adjacent to the heating block.
8. An apparatus substantially as described herein with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB878703185A GB8703185D0 (en) | 1987-02-12 | 1987-02-12 | Melting point apparatus |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8803169D0 GB8803169D0 (en) | 1988-03-09 |
| GB2202941A true GB2202941A (en) | 1988-10-05 |
| GB2202941B GB2202941B (en) | 1991-11-27 |
Family
ID=10612149
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB878703185A Pending GB8703185D0 (en) | 1987-02-12 | 1987-02-12 | Melting point apparatus |
| GB8803169A Expired - Fee Related GB2202941B (en) | 1987-02-12 | 1988-02-11 | Melting point apparatus |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB878703185A Pending GB8703185D0 (en) | 1987-02-12 | 1987-02-12 | Melting point apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8703185D0 (en) |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4927270A (en) * | 1987-11-18 | 1990-05-22 | Bonnard John A | Method of and apparatus for determining melting points |
| EP0397936A1 (en) * | 1989-05-16 | 1990-11-22 | Bizhan Rahimzadeh | Improvements in or relating to determining the temperature at which a substance changes state |
| US5088833A (en) * | 1988-02-10 | 1992-02-18 | Nova Husky Research Corporation | Method and apparatus for monitoring cloud point or like transition temperature |
| US5092679A (en) * | 1990-12-14 | 1992-03-03 | Brotz Gregory R | Melting point determination apparatus and method |
| US5299867A (en) * | 1992-06-30 | 1994-04-05 | Buck Arden L | Low moisture cryogenic hygrometer |
| DE4411242A1 (en) * | 1994-03-31 | 1995-10-05 | Roehrl Elektroanlagen & Geraet | Apparatus for establishing melting point of sample substance |
| DE10007102A1 (en) * | 2000-01-24 | 2001-08-02 | Metallurg Ges Fuer Huettenwerk | Investigating the properties of metallurgical covering agents, e.g. casting powder comprises electrothermally heating a sample of the covering agent to a prescribed temperature and visually displaying the behavior of the sample |
| US6536944B1 (en) * | 1996-10-09 | 2003-03-25 | Symyx Technologies, Inc. | Parallel screen for rapid thermal characterization of materials |
| US6604852B1 (en) * | 2000-12-09 | 2003-08-12 | Halliburton Energy Services, Inc. | High pressure brine crystallization point apparatus |
| US6726360B2 (en) * | 2002-03-27 | 2004-04-27 | Council Of Scientific And Industrial Research | Intensity modulated fiber optic temperature switching immersion probe |
| US6827484B2 (en) * | 2002-07-09 | 2004-12-07 | Charles Y. Tsang | Cloud point monitoring device |
| GB2406904A (en) * | 2003-10-09 | 2005-04-13 | Asahi Chemical Ind | Measuring the melting, softening or decomposition points by detecting a change in luminosity or reflectance of the sample |
| WO2009031083A1 (en) * | 2007-09-03 | 2009-03-12 | Philips Intellectual Property & Standards Gmbh | Sensor device for solid-liquid phase transition |
| CN110487839A (en) * | 2019-08-16 | 2019-11-22 | 河北省产品质量安全检测技术中心 | Image method fuse salt melting point apparatus |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109444207A (en) * | 2018-09-27 | 2019-03-08 | 宁波职业技术学院 | A kind of melting point compound detector and its measuring method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB910914A (en) * | 1960-03-08 | 1962-11-21 | Exxon Research Engineering Co | Pour point apparatus and process for using same |
| US3545254A (en) * | 1968-02-13 | 1970-12-08 | Shell Oil Co | Cloud point detector |
-
1987
- 1987-02-12 GB GB878703185A patent/GB8703185D0/en active Pending
-
1988
- 1988-02-11 GB GB8803169A patent/GB2202941B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB910914A (en) * | 1960-03-08 | 1962-11-21 | Exxon Research Engineering Co | Pour point apparatus and process for using same |
| US3545254A (en) * | 1968-02-13 | 1970-12-08 | Shell Oil Co | Cloud point detector |
Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4927270A (en) * | 1987-11-18 | 1990-05-22 | Bonnard John A | Method of and apparatus for determining melting points |
| US5088833A (en) * | 1988-02-10 | 1992-02-18 | Nova Husky Research Corporation | Method and apparatus for monitoring cloud point or like transition temperature |
| EP0397936A1 (en) * | 1989-05-16 | 1990-11-22 | Bizhan Rahimzadeh | Improvements in or relating to determining the temperature at which a substance changes state |
| WO1990014592A1 (en) * | 1989-05-16 | 1990-11-29 | Bizhan Rahimzadeh | Improvements in or relating to determining the temperature at which a substance changes state |
| US5092679A (en) * | 1990-12-14 | 1992-03-03 | Brotz Gregory R | Melting point determination apparatus and method |
| US5299867A (en) * | 1992-06-30 | 1994-04-05 | Buck Arden L | Low moisture cryogenic hygrometer |
| US5460450A (en) * | 1992-06-30 | 1995-10-24 | Buck; Arden L. | Cryogenic hygrometer |
| DE4411242A1 (en) * | 1994-03-31 | 1995-10-05 | Roehrl Elektroanlagen & Geraet | Apparatus for establishing melting point of sample substance |
| US6536944B1 (en) * | 1996-10-09 | 2003-03-25 | Symyx Technologies, Inc. | Parallel screen for rapid thermal characterization of materials |
| DE10007102C2 (en) * | 2000-01-24 | 2001-11-22 | Metallurg Ges Fuer Huettenwerk | Method and device for investigating properties of metallurgical covering agents |
| DE10007102A1 (en) * | 2000-01-24 | 2001-08-02 | Metallurg Ges Fuer Huettenwerk | Investigating the properties of metallurgical covering agents, e.g. casting powder comprises electrothermally heating a sample of the covering agent to a prescribed temperature and visually displaying the behavior of the sample |
| US6604852B1 (en) * | 2000-12-09 | 2003-08-12 | Halliburton Energy Services, Inc. | High pressure brine crystallization point apparatus |
| US6726360B2 (en) * | 2002-03-27 | 2004-04-27 | Council Of Scientific And Industrial Research | Intensity modulated fiber optic temperature switching immersion probe |
| US6827484B2 (en) * | 2002-07-09 | 2004-12-07 | Charles Y. Tsang | Cloud point monitoring device |
| US6966692B2 (en) * | 2002-07-09 | 2005-11-22 | Phase Technology | Cloud point monitoring device |
| GB2406904A (en) * | 2003-10-09 | 2005-04-13 | Asahi Chemical Ind | Measuring the melting, softening or decomposition points by detecting a change in luminosity or reflectance of the sample |
| WO2005036149A1 (en) * | 2003-10-09 | 2005-04-21 | University Of Southampton | Measurement of melting points of multiple samples |
| US8092078B2 (en) | 2003-10-09 | 2012-01-10 | University Of Southampton | Measurement of melting points of multiple samples |
| WO2009031083A1 (en) * | 2007-09-03 | 2009-03-12 | Philips Intellectual Property & Standards Gmbh | Sensor device for solid-liquid phase transition |
| CN110487839A (en) * | 2019-08-16 | 2019-11-22 | 河北省产品质量安全检测技术中心 | Image method fuse salt melting point apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2202941B (en) | 1991-11-27 |
| GB8703185D0 (en) | 1987-03-18 |
| GB8803169D0 (en) | 1988-03-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940211 |