GB2043246A - Determining crystallisation temperature - Google Patents
Determining crystallisation temperature Download PDFInfo
- Publication number
- GB2043246A GB2043246A GB8003631A GB8003631A GB2043246A GB 2043246 A GB2043246 A GB 2043246A GB 8003631 A GB8003631 A GB 8003631A GB 8003631 A GB8003631 A GB 8003631A GB 2043246 A GB2043246 A GB 2043246A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cell
- liquid
- tubular member
- temperature
- flow
- 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
Links
- 238000002425 crystallisation Methods 0.000 title abstract description 5
- 239000007788 liquid Substances 0.000 claims abstract description 31
- 238000012360 testing method Methods 0.000 claims abstract description 24
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 230000003287 optical effect Effects 0.000 claims description 3
- 230000001419 dependent effect Effects 0.000 claims description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 2
- 229910052753 mercury Inorganic materials 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims 2
- 238000011144 upstream manufacturing Methods 0.000 claims 1
- 238000001816 cooling Methods 0.000 abstract description 8
- 230000008025 crystallization Effects 0.000 abstract 1
- 239000000446 fuel Substances 0.000 description 13
- 239000013078 crystal Substances 0.000 description 2
- 238000007710 freezing Methods 0.000 description 2
- 230000008014 freezing Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000004794 expanded polystyrene Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B25/00—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/26—Oils; Viscous liquids; Paints; Inks
- G01N33/28—Oils, i.e. hydrocarbon liquids
- G01N33/2811—Oils, i.e. hydrocarbon liquids by measuring cloud point or pour point of oils
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Thermal Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
A liquid under test is held in a cell 11 whose temperature can be varied and which includes a tube 14 with its end covered by a mesh 15. In use, the liquid within the tube 14 is displaced through the mesh by tilting a mercury- filled U-tube 20 and then allowing it to return; the pressure-drop across the mesh increases when crystallization increases and is measured by a manometer 32. The cell is formed as a bore in a block 12 with sighting rods 21, 22. Cooling is effected by a Pelteer device (50, Figure 2, not shown) in combination with a compression-type refrigerator (50, 43, 48). <IMAGE>
Description
SPECIFICATION
Improved liquid testing apparatus
This invention restates to liquid testing apparatus of the kind in which a characteristic of the liquid is determined.
One example of a use for such apparatus arises in connection with measuring particular properties of aviation fuel. Fuel of this type contains a certain proportion of wax which crystallises out at a temperature considerably below normal ambient temperature, this crystallisation temperature being-depen- dent on a number of factors, one of which is the particular proportion of wax in the fuel. It is necessary to determine this temperature in order to find whether the fuel meets certain prescribed standards.
A known method of determining the wax crystallisation temperature is laid down in the joint specification I 6 - ASTM D 2386 of the Institute of Petroleum and the American Society for Testing and Materials.
This involves visual monitoring of a fuel sample as the temperature. is steadily lowered. Crystallisation of the wax is seen asa precipation in the previously clear liquid.
A problem with this known testing method is that ai degree of subjectivity is introduced as a result of the visual inspection, and therefore the accuracy of the determination is dependent on the skill af the tester.
It is an object of the present invention to provide improved liquid testing apparatus which removes the subjective aspect in the determination of a characteristic of the liquid being tested.
Apparatus according to the invention enables liquid being tested to be passed through a restriction, such as a mesh filter, and measuring the obstruction to flow through the restriction as the teniperature is varied. A change in the physical state of the liquid may be detected as a variation in the degree of obstruction to flow. In the above example of testing aviation fuel, the temperature is gradually lowered and when wax crystals begin to form in the fuel sample, the impeded flow of fuel through the restriction will indicate this change of state, and the indicated temperature will be that at which the fuel is no longer suitable for use.
From another aspect the invention provides liquid testing apparatus including a testing cell formed by a vertical bore in a metal block and having disposed therewithin a transparent tubular member depending from a cover member closing the top of the cell, said tubular member having its lower end spaced from the bottom of the cell and covered by a mesh filter, aligned transparent rods passing through said block and arranged so that their inner ends form walls of said cell, means arranged to allow the introduction of a liquid sample into said cell and means for introducing and/or extracting air from the top of the spaces of said cell within and without said tubular member.
A liquid testing apparatus embodying the invention will now be described with reference to the accompanying drawings, in which:
Figure lisa sectional view of the apparatus; and
Figure 2 shows part of apparatus similar-to that of
Figure 1, including a-temperature controlling means.
Referring to Figure 1, there is shown a liquid testing apparatus comprising a testing cell.assembly 10 together with ancilliary devices. The cell proper is formed by.a cylindricai vertical bore 11 in a metal block 12, conveniently of aluininium. Bore 11. is closed upwardly by a cover plate 13 to which is secured a transparent cylindrical tubular member 14 projecting downwardly from cover plate. 13 and concentric with bore 11. The upper end of tubular member 14 is secured inan air-tight manner to cover plate 13 and its lower end is covered by a mesh filter 15, preferabiy.a 400 mesh stainless steel filter.Cover plate 13 is provided with tubulations 16,17 affording communication from outside the cell to the spaces at the top of the cell within and without the tubular member 14, respectively. A temperature sensor 18 passes through cover plate.13 and provides-atT an electrical signal denotive of the temperature of liquid within the cell. Atthe lowermost point 19 of the cell there is provided a -duct 20 through which a sample of liquid to be tested may be introduced into the cell.
Transparent rods 21, 22 are fitted into aligned bores 23, 24 respectively in the cell block 1-1 and permit optical observation of the interior of the cell, to which end illumination may be provide by a light source 25, light from which is diffused used by means of a translucent diffusor plate 26.
The temperature of the cell may be controlled by heating and/or cooling means 27. The device for this purpose may very conveniently be as described hereafter and in more detail in co-pendingrPatent Application No. 47,124/77, the rate of change of temperature of the liquid under test controlled as described.in the aforesaid co-pending applica-tion.
The operation of the apparatus is as fox low Approximately 6ml of sample is injected into the cell via duct 20 by means of a hypodermic syringe which is left connected. The air displaced from the cell escapes via a drying chamber 29.containing silica gel.
A mercury filled U-tube one end'ofwhich is coupled to tubulation 16 by a tube 31 is tilted through a pre-determined angle ato-provide air.
pressure toPhe inner cell. This air pressuore slisplaces the fuel from the inner cell to the outer cell,.via filter 15, and is maintained for approximately one second, the pressure is then removed for one second to allow the fuel to refill the inner cell.
A manometer 32 coupled between the tubulations 16 and 17 measures the pressure and vacuum developed across the filter.
When crystals form in the liquid samples-as the temperature falls the flow through the filter isimpeded and the pressure increases. When the pressure across the filter exceeds Omrn Hg for one second (1 stroke of pump) this is taken as the lowest temperature at which the fuel ceases to flow. The test cell is then allowed to warm and the temperature at which the flow re-commences can also be noted.
Cooling of the cell assembly is preferably achieved by the combination of compressor refrigeration and thermo-electric cooling as described hereinafter and in aforeaid Patent Application No. 47124/77, giving control of temperature from 0 to -700C.
The test cell being completely sealed prevents the formation of condensation.
The flow rate of 1 ml per second at a pressure of 1 Omm Hg via a 400 mesh filter was chosen as tests on fuels of known freezing point by 1 P16 gave correct results under these conditions. All of these parameters may be changed if necessary to more closely represent actual operation conditions.
A cooling rate of approximately 20C/min near the freezing point is used and a complete test can be completed in 15 minutes.
Figure 2 shows in more detail one example of the heating and/or cooling means of Figure 1.
The apparatus 40 of Figure 2 includes a reference body, in this case a heat sink, provided by the evaporator block 41 of a refrigerator system. This evaporator, which includes an internal cavity in which a refrigerant liquid is evaporated to produce cooling of the block, is coupid by way of conduits 42 to a compressor and expansion valve assembly 43 including a compressor operated by an electric motor 44 fed from an a.c. power supply 45 by way of a control means 46 responsive to the temperature of evaporator block 41, as sensed by a temperature sensor 47 applied to the evaporator block 41.
Assembly 43 is also coupled to a condenser 43 for dissipating heat extracted from evaporator block 41.
The arrangement described above operates in well known manner to hold the temperature of evaporator block 41 at a predetermined temperature below ambient for example 5 C.
The apparatus 40 also includes an observation cell
10 similar to that described above in relation to
Figure 1 which is required to be capable of being taken to a temperature substantially below that of
reference body 41, for example, to -50 C. In accord
ance with the arrangement a Peltier device 50 is
interposed between the reference body 41 and cell
10 and is energised from a direct current source 51 to
reduce the temperature of cell 10 by the required
amount with respect to reference body 41. The
current supplied to Peltier device 50, which is a
known, commercially available unit, is controlled by
appropriate means 52, illustrated as comprising a
switch 53 and a variable resistor 54.It is apparent
that more complex control means may readily be
provided if required, for example, automatic control
means to provide a required rate of temperature
decrease and/or increase may be known manner
respond to temperature-denotive signals developed
by a sensor applied to or incorporated in cell 10,
conveniently the temperature sensor 18. It is an
advantage of the apparatus described that the Peltier
device is conveniently operated at a low direct
voltage, for example 6V or 1 2V, so that control by
known semiconductor switching devices is very
simple.
The whole of the cooling means 40, 50, together
with cell lOis enclosed by thermal insulation 60
provided by an envelope of thermal insulating
material, conveniently expanded polystyrene, to
reduce ingress of heat from the ambience. Rods 21,
22 of the cell 10 are made of such a length that they extend to the outer surface of thermal insulation 60, so that illumination and viewing of the interior of well 12 is assisted.
An advantage of the apparatus as described is that the transparent rods 21, 22 together with the light source 25 and diffusor 26 allow optical observation of the interior of the cell, and therefore the apparatus conforms to the specification IP16.
Claims (17)
1. Liquid testing apparatus comprising flow restricting means disposed in a flow path of liquid being tested, means for causing the liquid to pass through said flow restricting means, detecting means for detecting variations in the resistance to flow of the liquid provided by said flow restricting means, and means for indicating the temperature of the liquid.
2. Apparatus as claimed in claim 1, wherein said flow restricting means comprises a mesh filter disposed in said flow path.
3. Apparatus as claimed in claim 2, wherein said mesh filter has a gauge of 400 mesh.
4. Apparatus as claimed in claim 2 or 3, wherein said mesh filter is made of stainless steel.
5. Apparatus as claimed in any preceding claim further including temperature controlling means for controlling the temperature of the liquid being tested.
6. Apparatus as claimed in claim 5, wherein said temperature controlling means includes a Peltier device.
7. Apparatus as claimed in any preceding claim, wherein said flow path is provided in a testing cell comprising a metal block with a vertical bore in said block.
8. Apparatus as claimed in claim 7, wherein said testing cell furthe includes a tubular member and a cover member closing the top of said cell, said tubular member depending from said cover member into said bore.
9. Apparatus as claimed in claim 8 as dependent on claim 2,3 or 4, wherein said mesh filter is attached to said tubular member.
10. Apparatus as claimed in claim 8 or 9, further including transparent means provided in said metal block whereby an optical path is provided through said testing cell, and wherein said tubular member is transparent.
11. Apparatus as claimed in claim 10, wherein said transparent means comprises aligned transparent rods provided in corresponding bores of said metal block.
12. Apparatus as claimed in any preceding claim wherein said means for causing the liquid to pass through said flow restricting means comprises a device for applying pressure to said liquid.
13. Apparatus as claimed in claim 12, wherein said device for applying pressure comprises a tiltable mercury filled U-tube having one end thereof connected to said flow path.
14. Apparatus as claimed in any preceding claim wherein said flow resistance detecting means com
prises a pressure responsive device connected upstream and downstream of said flow restricting means, thereby providing an indication of pressure differential across said flow restricting means and hence of flow resistance provided thereby.
15. - Liquid testing apparatus including a testing cell formed by a vertical bore in a metal block and having disposed therewith a transparent tubular member depending from a cover member closing the top of the cell, said tubular member having its lower end spaced from the bottom of the cell and covered by a mesh filter, aligned transparent rods passing through said block and arranged so that their inner ends form walls of said cell, means arranged to allow the introduction of a liquid sample into said cell and means for introducing and/or extracting air from the top of the spaces of said cell within and without said tubular member.
16. Apparatus as claimed in claim 15further including means for controlling the temperature of the liquid sample in said cell.
17. Liquid testing apparatus substantially as hereinbefore described with reference to Figure 1 or
Figure 2 in combination with Figure 1 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8003631A GB2043246B (en) | 1979-02-02 | 1980-02-04 | Determining crystallisation temperature |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7903772 | 1979-02-02 | ||
| GB8003631A GB2043246B (en) | 1979-02-02 | 1980-02-04 | Determining crystallisation temperature |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2043246A true GB2043246A (en) | 1980-10-01 |
| GB2043246B GB2043246B (en) | 1983-06-15 |
Family
ID=26270438
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8003631A Expired GB2043246B (en) | 1979-02-02 | 1980-02-04 | Determining crystallisation temperature |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2043246B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0358403A2 (en) * | 1988-09-08 | 1990-03-14 | Exxon Chemical Patents Inc. | Process for assessing cold start performance of a wax containing fuel |
| GB2294362A (en) * | 1994-10-18 | 1996-04-24 | Air Liquide | Cryogenic device for optoelectronic and/or electronic equipment |
| EP1215483A1 (en) * | 2000-12-09 | 2002-06-19 | Halliburton Energy Services, Inc. | Apparatus and method for measuring the crystallization point of a fluid comprising brine |
| CN112816518A (en) * | 2021-01-05 | 2021-05-18 | 华北水利水电大学 | Method and device for testing supercooling degree thermal boundary in solidification process in circular tube |
-
1980
- 1980-02-04 GB GB8003631A patent/GB2043246B/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0358403A2 (en) * | 1988-09-08 | 1990-03-14 | Exxon Chemical Patents Inc. | Process for assessing cold start performance of a wax containing fuel |
| EP0358403A3 (en) * | 1988-09-08 | 1991-01-02 | Exxon Chemical Patents Inc. | Process for assessing cold start performance of a wax containing fuel |
| US5046355A (en) * | 1988-09-08 | 1991-09-10 | Exxon Chemical Patents Inc. | Process for assessing cold start performance of a wax containing fuel |
| GB2294362A (en) * | 1994-10-18 | 1996-04-24 | Air Liquide | Cryogenic device for optoelectronic and/or electronic equipment |
| GB2294362B (en) * | 1994-10-18 | 1998-09-30 | Air Liquide | Cryogenic device for optoelectronic and/or electronic equipment and equipment comprising such a device |
| EP1215483A1 (en) * | 2000-12-09 | 2002-06-19 | Halliburton Energy Services, Inc. | Apparatus and method for measuring the crystallization point of a fluid comprising brine |
| US6604852B1 (en) | 2000-12-09 | 2003-08-12 | Halliburton Energy Services, Inc. | High pressure brine crystallization point apparatus |
| CN112816518A (en) * | 2021-01-05 | 2021-05-18 | 华北水利水电大学 | Method and device for testing supercooling degree thermal boundary in solidification process in circular tube |
| CN112816518B (en) * | 2021-01-05 | 2024-02-13 | 华北水利水电大学 | Method and device for testing supercooling degree thermal boundary in solidification process in circular tube |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2043246B (en) | 1983-06-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20000203 |