CN87208429U - Phase equilibria melting point precise detecting unit - Google Patents
Phase equilibria melting point precise detecting unit Download PDFInfo
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- CN87208429U CN87208429U CN 87208429 CN87208429U CN87208429U CN 87208429 U CN87208429 U CN 87208429U CN 87208429 CN87208429 CN 87208429 CN 87208429 U CN87208429 U CN 87208429U CN 87208429 U CN87208429 U CN 87208429U
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- melting point
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- fusing point
- detecting unit
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- 238000002844 melting Methods 0.000 title abstract description 14
- 230000008018 melting Effects 0.000 title abstract description 13
- 238000012360 testing method Methods 0.000 claims abstract description 17
- 239000004065 semiconductor Substances 0.000 claims abstract description 6
- 239000007788 liquid Substances 0.000 claims description 7
- 239000011521 glass Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 7
- 239000012071 phase Substances 0.000 abstract description 6
- 239000000126 substance Substances 0.000 abstract description 6
- 239000007791 liquid phase Substances 0.000 abstract description 2
- 239000007790 solid phase Substances 0.000 abstract description 2
- 238000010438 heat treatment Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- 238000003556 assay Methods 0.000 description 2
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- 238000001514 detection method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- SPSSULHKWOKEEL-UHFFFAOYSA-N 2,4,6-trinitrotoluene Chemical compound CC1=C([N+]([O-])=O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O SPSSULHKWOKEEL-UHFFFAOYSA-N 0.000 description 1
- 238000003287 bathing Methods 0.000 description 1
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- 238000000151 deposition Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011067 equilibration Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000009191 jumping Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
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- 230000008569 process Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000000015 trinitrotoluene Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
The utility model discloses a melting point precise detecting unit, which is designed according to the phase equilibria principle; the temperature of the solid and liquid phase equilibria-melting point of the test sample can be directly measured by a semiconductor thermal element; some inherent disadvantages of the capillary method meldometer are overcome; the utility model has the advantages of high test precision if the melting point is lower than 200 DEG C, the error is not greater than 0.1 DEG C) and simple structure; a plurality of test samples can be tested simultaneously; the melting point precise detecting unit is suitable for testing the melting point which is below 300 DEG C and the solidifying point of the chemical substance.
Description
This device is used for the micrometric measurement of chemical substance fusing point, belongs to the thermal analyzer table.
Existing differential thermal and differential thermal analyzer.All can be used for fusing point test, but because precision is not high, equipment is complicated, not seen widespread use.Russian Patent (su842527) mechanical type melting point detector.Only be suitable for fusing point at 300～1500 ℃ of substance-measurings such as metal.Fusing point is at the chemical substance melting point detector below 300 ℃, since the seventies, the FP5 type photo-electric capillary melting point determination instrument that has only Switzerland Met-tler company to produce obtains to be in great demand, they improved to some extent again (Swiss Patent CH592875) afterwards, but sample is still put in the glass capillary and measured; The WRS-1 type numeral fusing point instrument that China's Shanghai Physics Optics Instrument Factory is produced.It is the improvement (" optical instrument " 84 years the 6th the 1st phases of volume) on Switzerland FP61 type basis.The mensuration precision of all these capillary melting point determination instrument generally is ± 0.5 ℃ (fusing point is person below 200 ℃).It is more to influence this method mensuration factors of accuracy, its basic reason, just because of based on kapillary mechanism was determined, for example several milligrams of samples are packed in the kapillary, it is that the periphery bath temperature is indicated fusing point indirectly when changing by the luminous flux before and after the sample fusing in the kapillary that its fusing point detects.Thereby wall thickness capillaceous, diameter, tube wall cleaning degree of drying, factors such as sample granularity, loading amount and tightness thereof are inevitably brought influence to measuring precision; Secondly the rate of heat addition and the initial temperature difference of temperature programme also have certain influence in measuring.Therefore if on the kapillary basis, improve, increase in the time of perhaps on precision, but be difficult to stand for a long time the test that various variable factors change.We think when jumping out constraint capillaceous.Searching directly contacts with sample with thermal sensing element, and the true temperature when directly predicting sample heating phase transformation can overcome the inherent defect of above-mentioned capillary tube technique, stably improves and measures precision, starting point of this research that Here it is and target.
According to the physical chemistry Phase Equilibrium theory: " fusing point of solid or the solidifying point of liquid all can regard the solid phase of pure material and the temperature of the mutual balance of liquid phase as " on the contrary (" principles of chemistry " beautiful W, L, MASTERTON work, Hua Tongwen etc. translate).This meaning can be regarded as: the temperature that balances each other, be sample solid-liquid two-phase and the temperature when depositing, if when variation of ambient temperature is little, the temperature that then balances each other remains unchanged, up to sample become one mutually till; Environment temperature differs big more with the temperature that balances each other, and the time of then balancing each other is short more; Sample is many more, and the time of balancing each other is long more.If can accurately measure the temperature that balances each other.Then this temperature is the fusing point or the solidifying point of sample.General classical kryoscopy is peek ten gram samples, directly measures heat release in the sample process of setting with common mercury thermometer in test tube.Temperature rise peak and the temperature when remaining unchanged, this some temperature that balances each other just.Yet the fusing point test of various chemical substances always (comprising classical capillary tube technique).Because judging the standard of sample fusing when range estimation or Photoelectric Detection is not quite similar, document and document appear, document is of common occurrence with the inconsistent phenomenon of actual measurement, and often melting point values is higher than solidifying point, does not cause just because of capillary melting point determination does not balance each other temperature.Therefore, key is how to explore feasible condition, and temperature is accurately measured to realize balancing each other.Proof from experiment: purer though the vague generalization chemical product is not absolute pure material, can record the temperature that balances each other.
This determinator below is described further as accompanying drawing 1:
(1): the exact constant temperature groove, and the journey temperature control is arranged, and in the liquid bath, working temperature is adorned water below 95 ℃, dress glycerine or silicone oil more than 95 ℃, and the constant temperature precision is ± 0.01 ℃.
(2): specific glass test tube, the spherical usefulness of containing sample in bottom.
(3): semiconductor thermistor (or transistor PN junction sensor)
(4): the direct current bridge circuit
(5): electron potentiometer (single or many) 0-1mv.
Assay method: for recording the temperature curve that balances each other fast, heating medium---liquid, set up appropriate heat transfer coupling with glass test tube, powdery sample three, thermistor is as an arm of direct current bridge circuit, with temperature---resistance variations converts millivolt signal to through electric bridge, imports electron potentiometer and record, the current-limiting resistance in the bridge circuit, the control thermal sensing element makes enough detection sensitivities and stability by appropriate electric current.Thermal sensing element before measuring is put the sky test tube in advance, puts into calibration cell, carries out the bound calibration (with the standard thermometer contrast) of working temperature, promptly can be used for full pattern then and measures.Mensuration is preceding as being known sample, can be warm constant on the temperature that is higher than 0.5-1 ℃ of sample fusing point with bathing, as be unknown sample, can be earlier with behind the roughly definite melting range of temperature programme, constant temperature is accurately measured again.Determination step is: 0.2～0.5 gram of packing in the clean tube is pulverized sample, insert thermal sensing element again, put into the permanent liquid bath to working temperature with being about to test tube, heat transfers to sample and thermal sensing element by test tube, registering instrument---and the temperature curve on the electronics tentiometer just rises gradually.Begin fusing up to sample since sample when fusing endothermic effect normally, cause specimen temperature no longer sharply to rise (descending a bit on the contrary sometimes), along with the sample limit is heated, fusing of marginization, absorbing heat in the limit, has formed and balanced each other.The situation that temperature stabilization occurs, the recording curve on the potential difference meter keep straight, and this temperature is the sample fusing point, along with sample the more, equilibration time is longer, generally keeps get final product in 1～2 minute, the sample amount determines thus, after sample all melts.Recording curve rises once more, till rising to the liquid bath temperature, typical curve as
Shape.
Actual measurement is given an example: measure industrial trinitro-toluene, with G N-type semiconductor N thermistor, the bath temperature is constant in 80.7 ℃, and sample is got 0.2～0.3 gram, same sample repeats ten times and measures, and the fusing point result is: 80.43,80.44,80.46,80.44,80.43,80.44,80.41,80.39,80.40 80.44 average 80.42 ℃, the former state solidifying point is 80.41 ℃, as seen consistent with the solidifying point result, precision is also identical with it, and the mensuration cycle is 10～15 minutes.
From as can be seen last, this device has following characteristics:
1. can truly measure the temperature that balances each other of chemical substance, overcome some inherent defects of capillary tube technique substantially.Test tube size, sample amount and particle size influences are little in the mensuration; The sample amount is more than 10 times of capillary tube technique, and is more representative; Under constant temperature, measure, influence of no heating rate and initial temperature or the like, thereby can keep than high assay precision (fusing point person below 200 ℃, error is not more than 0.1 ℃), determinator is simple, and is cheap.
2. mensuration cycle weak point can carry out a plurality of samples simultaneously and measure; Can further make numeral and show the automatic instrument of information storage.
3. be the temperature that balances each other owing to what measure, with the kryoscopy equivalence, thereby this law can replace kryoscopy.
Claims (3)
1, according to balancing each other principle, designed a kind of accurate fusing point apparatus for automatically measuring.It is characterized in that: with the semiconductor heat photosensitive elements is a kind of easy fusing point test device that the mensuration circuit formed of detecting element, bottom glass test tube that is bulbous upper portion and thermal sensing element tight connecting and exact constant temperature liquid bath are constituted.
2, semiconductor heat photosensitive elements according to claim 1 is characterized in that: it can be a semiconductor thermistor.It also can be transistor PN junction sensor.
3, device according to claim 1, its testing circuit is characterised in that: thermistor is as an arm of conventional DC bridge circuit.This bridge circuit also has current limliting and balancing potentiometer except that three fixed resistances, uneven electric potential signal in bridge circuit during mensuration is directly imported 1mv electron potentiometer record.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87208429 CN87208429U (en) | 1987-05-23 | 1987-05-23 | Phase equilibria melting point precise detecting unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 87208429 CN87208429U (en) | 1987-05-23 | 1987-05-23 | Phase equilibria melting point precise detecting unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN87208429U true CN87208429U (en) | 1988-05-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 87208429 Pending CN87208429U (en) | 1987-05-23 | 1987-05-23 | Phase equilibria melting point precise detecting unit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN87208429U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1314957C (en) * | 2004-09-28 | 2007-05-09 | 东南大学 | Detection device for drawing temperature-controlled phase diagram of nanoemulsion |
| CN106814099A (en) * | 2017-01-04 | 2017-06-09 | 中国工程物理研究院化工材料研究所 | Freezing point, fusing point or crystalline temperature automatization test system |
-
1987
- 1987-05-23 CN CN 87208429 patent/CN87208429U/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1314957C (en) * | 2004-09-28 | 2007-05-09 | 东南大学 | Detection device for drawing temperature-controlled phase diagram of nanoemulsion |
| CN106814099A (en) * | 2017-01-04 | 2017-06-09 | 中国工程物理研究院化工材料研究所 | Freezing point, fusing point or crystalline temperature automatization test system |
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