GB2034032A - Detection of a Specific Substance in a Bulk Fluid - Google Patents
Detection of a Specific Substance in a Bulk Fluid Download PDFInfo
- Publication number
- GB2034032A GB2034032A GB7932669A GB7932669A GB2034032A GB 2034032 A GB2034032 A GB 2034032A GB 7932669 A GB7932669 A GB 7932669A GB 7932669 A GB7932669 A GB 7932669A GB 2034032 A GB2034032 A GB 2034032A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tube
- fluid
- probe
- specific substance
- collecting medium
- 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
- 239000012530 fluid Substances 0.000 title claims abstract description 71
- 239000000126 substance Substances 0.000 title claims abstract description 61
- 238000001514 detection method Methods 0.000 title claims description 6
- 239000000523 sample Substances 0.000 claims abstract description 67
- 239000007788 liquid Substances 0.000 claims abstract description 54
- 239000010865 sewage Substances 0.000 claims abstract description 39
- 239000012528 membrane Substances 0.000 claims abstract description 36
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 34
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims abstract description 15
- QPJDMGCKMHUXFD-UHFFFAOYSA-N cyanogen chloride Chemical compound ClC#N QPJDMGCKMHUXFD-UHFFFAOYSA-N 0.000 claims abstract description 15
- VDQQXEISLMTGAB-UHFFFAOYSA-N chloramine T Chemical compound [Na+].CC1=CC=C(S(=O)(=O)[N-]Cl)C=C1 VDQQXEISLMTGAB-UHFFFAOYSA-N 0.000 claims abstract description 14
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 9
- 238000012360 testing method Methods 0.000 claims abstract description 9
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 claims abstract description 8
- 150000002500 ions Chemical class 0.000 claims abstract description 7
- HNYOPLTXPVRDBG-UHFFFAOYSA-N barbituric acid Chemical compound O=C1CC(=O)NC(=O)N1 HNYOPLTXPVRDBG-UHFFFAOYSA-N 0.000 claims abstract description 4
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 28
- 239000000376 reactant Substances 0.000 claims description 17
- 239000007789 gas Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 10
- 230000001419 dependent effect Effects 0.000 claims description 8
- 239000012466 permeate Substances 0.000 claims description 6
- 230000003287 optical effect Effects 0.000 claims description 4
- 239000001913 cellulose Substances 0.000 claims description 3
- 229920002678 cellulose Polymers 0.000 claims description 3
- 239000000047 product Substances 0.000 claims description 2
- 238000005086 pumping Methods 0.000 claims description 2
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- 238000004040 coloring Methods 0.000 claims 2
- 239000012159 carrier gas Substances 0.000 claims 1
- 230000005587 bubbling Effects 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 3
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000000502 dialysis Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000276 potassium ferrocyanide Substances 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- XOGGUFAVLNCTRS-UHFFFAOYSA-N tetrapotassium;iron(2+);hexacyanide Chemical compound [K+].[K+].[K+].[K+].[Fe+2].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] XOGGUFAVLNCTRS-UHFFFAOYSA-N 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- 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
- G01N33/18—Water
- G01N33/182—Specific anions in water
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
-
- 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
- G01N33/18—Water
- G01N33/1886—Water using probes, e.g. submersible probes, buoys
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Biophysics (AREA)
- Molecular Biology (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The presence of a specific substance in a bulk fluid is detected by immersing directly in the bulk fluid a probe 1 comprising a tube 2 formed from a semi-permeable membrane through which ions or molecules of the specific substance can diffuse into the tube from the bulk fluid and pass through the tube to a collecting medium which removes them from the tube either unchanged or as a specific reaction product thereof, and testing the collecting medium which leaves the tube for the presence of the specific substance or the specific reaction product, in an example cyanide in sewage is detected by bubbling air through a solution of chloramine T in the tube 2 when the tube is immersed vertically in the sewage 27, and analysing the fluid leaving the tube 2 for the presence of cyanogen chloride by reacting the fluid with barbituric acid in pyridine and hydrochloric acid and measuring the resulting liquid colorimetrically. <IMAGE>
Description
SPECIFICATION
Improvements Relating to the Detection of a
Specific Substance in a Bulk Fluid
This invention relates to the detection of specific substances in bulk fluids, including complex liquids, such as sewage which comprises a large number of different components and invariably includes a proportion of solids or sludge.
Conventional techniques for detecting the presence of a specific substance in a fluid usually involve taking a sample of the fluid and testing the sample to determine whether or not it contains any of the specific substance. With complex liquids such as sewage, however, taking a sample can often be a messy business and the sample may well not be truly representative of the bulk liquid being tested so that a false reading for the amount of the specific substance in the bulk liquid may be obtained. In addition, complex liquids such as sewage are not suited to the techniques of continuously monitoring a fluid for the presence of a specific substance in which a sample is continuously withdrawn from the fluid and is subjected to continuous test automatically.
In one such technique, for example, the sample which is withdrawn from the fluid is passed through a narrow tube having a semi-permeable interface with another narrow tube through which a reactant is passed to an analyser for measuring the content, if any, of a specific product which results from a reaction between the reactant and any of the specific substance which diffuses through the interface from the sample. Here again, with complex liquids the sample which flows through the tube may not be truly representative of the bulk liquid. Furthermore, the presence of solids in the liquid can cause blockages in the sample tube which distort or interrupt the operation of the monitor, and even if the solids are filtered out before the liquid is passed through the sample tube trouble may still be experienced if bacterial growth forms in the tube.
The aim of the present invention is to provide a method and apparatus which can be used successfully to detect the presence of specific substances in any bulk fluid, including complex liquids such as sewage, and according to one aspect of the invention, a method of detecting the presence of a specific substance in a bulk fluid comprises immersing directly in the bulk fluid a tube at least part of which is formed by a membrane which is permeable to the specific substance, the membrane being exposed to the bulk fluid and the tube containing a collecting medium which collects ions or molecules of the specific substance which permeate through the membrane into the tube from the bulk fluid, and testing the contents of the tube for the presence of the specific substance or a specific reaction product thereof.
Preferably the collecting medium is passed through the tube so that the specific substance or the specific reaction product thereof is removed from the tube by the collecting medium, and the collecting medium is tested after it has left the tube. If the bulk fluid is to be monitored continuously for the presence of the specific substance, the method is simply operated by pumping the collecting medium continuously through the tube and continuously testing the collecting medium from the tube.
The method in accordance with the invention avoids the problems associated with the conventional techniques described earlier for monitoring certain bulk fluids for specific substances, by the simple expedient of avoiding the necessity to take and process a sample of the fluid. Instead, the bulk fluid is monitored in situ, i.e. in its natural environment, by immersing in the fluid a tube formed at least partly by a semipermeable membrane through which ions or molecules of the specific substance diffuse directly from the fluid into the tube, and passing a suitable medium through the tube to collect the diffused ions or molecules. Preferably the whole tube is made of the semipermeable membrane.
The collecting medium which is used will of course depend entirely on the specific substance to be detected and the type of testing to which it is to be subjected. Sometimes the collecting medium will simply be a carrier fluid which is intended to conduct the specific substance, either in solution of admixture, away from the tube as quickly as possible. More often, however, the collecting medium will comprise a reactant which is intended to react with the specific substance in the tube to form a specific reaction product, and in this case the collecting medium will usually also comprise a carrier fluid for conducting at least the reaction product from the tube.
The collecting medium may be gaseous, liquid, or a mixture of the two. In the case of a collecting medium comprising a mixture of a gas and a liquid, such as when the specific substance is a gas or produces a gaseous reaction product, the tube is preferably immersed vertically in the bulk fluid so that a gaseous component of the collecting medium is caused to bubble rapidly upwards through the tube to sweep away the specific substance or the reaction product It may also be advantageous to immerse the tube vertically in the bulk fluid when the collecting medium is a mixture of substantially immiscible liquids, although in this case it may sometimes be preferred to arrange the tube so that the medium flows downwards instead of upwards through the tube.
There are a number of known types of semipermeable membranes possessing different properties from each other, and in carrying out the method in accordance with the invention a tube will be used which makes use of the most suitable membrane having regard to the specific substance which is to be detected and the collecting medium which is to be passed through the tube. This should present no problem to an expert in the field of semi-permeable membranes.
According to a further aspect of the present invention, apparatus for use in detecting the presence of a specific substance in a bulk fluid comprises a probe including a tube having at least part, preferably the whole, of its wall formed by a membrane which is permeable to the specific substance, the probe also haviing an inlet and an outlet, means for connecting the inlet to a supply of a collecting medium, a pump for causing the collecting medium to flow through the probe, the inlet and the outlet being arranged so that the collecting medium flows along substantially the whole length of the tube, and an analyser which is connected to receive the collecting medium from the probe and which is sensitive to the presence of the specific substance or a specific reaction product thereof in the collecting medium.
The pump may be located downstream from the probe, but preferably it will be located upstream so that the collecting medium is supplied to the tube at a slight positive pressure.
In this case, even when the tube is made entirely from the semi-permeable membrane, the probe need have no internal means or supporting the membrane since it will be prevented from collapsing during use by means of the positive pressure of the collecting medium which is pumped through the tube. If desired, however, the tube may be provided with some internal support means which prevents the membrane from collapsing, but which will permit the collecting medium which is pumped through the tube during operation to contact the membrane. For example, such internal support means may comprise a polyethylene mesh support or a filling of glass beads.
If the collecting medium comprises a mixture of fluids, it may be necesary to provide a separate pump for each of the fluid components of the collecting medium, each pump having its outlet connected to the inlet of the probe. As will be appreciated, this will enable the different components to be supplied to the probe at different flow rates as required. Furthermore, the probe may include a diffuser, for example in the form of a perforated plate, in or adjacent the inlet for ensuring that, when the collecting medium comprises a mixture of fluids, the different fluid components of the collecting medium entering and flowing through the tube are well mixed or dispersed one within another. This is particularly necessary when the collecting medium comprises a gas and a liquid or comprises two immiscible liquids.
As mentioned earlier, in operation it is intended that the collecting medium which is pumped through the probe to the analyser should remove from the tube any ions or molecules of the specific substance which permeate through the tube from the bulk fluid under test, and, depending on the collecting medium used, the specific substance will be conducted to the analyser either as itself or as a specific reaction product. The analyser, which may of course be located at any suitable position remote from the probe and the bulk fluid, may be any suitable device capable of giving a signal, preferably electrical, or reading which is related to the amount of the specific substance or the amount of the specific reaction product contained in the collecting medium received from the probe.When the analyser is arranged to provide an electrical output signal, the signal may be arranged to trip a relay to sound an alarm, or to perform some other control function, upon the signal reaching a predetermined value. In addition, or alternatively, the output signal may be used to drive a meter or a chart recorder.
The analyser may be a device which is responsive to a physical property which varies according to the content of the specific substance or reaction product in the collecting medium.
Alternatively the analyser may be responsive chemically to the presence of the specific substance or reaction product, or it may be both chemically and physically responsive. For example, the analyser may comprise a colourimeter which is arranged to provide an electrical output signal or reading which is dependent upon the colour of a liquid of which the colour is dependent upon the amount of the specific substance or specific reaction product in the collecting medium, and hence on the amount of specific substance in the bulk fluid.If the collecting medium does not already comprise a liquid component which is coloured by the presence of the specific substance or the specific reaction product, the analyser will include a reaction vessel in which the collecting medium is reacted with another medium to produce a liquid which will be coloured in accordance with the amount of the specific substance or specific reaction product in the collecting medium.
As an example of the method and apparatus in accordance with the invention we shall now describe a specific form of method and apparatus which has been developed for continuously monitoring sewage for the presence of cyanide.
If sewage containing cyanide, such as from a careless industrial discharge, enters a sewage works, the organisms which are essential to the treatment of the sewage are killed and the sewage works temporarily has to be put out of action. In order to prevent this happening it is desirable to monitor the sewage flowing in each main pipe or channel leading to a sewage works so that on detecting the presence of cyanide in one of the pipes or channels, the entry of the sewage from the pipe or channel into the sewage works is shut off, and the flow of sewage diverted to a suitable storage tank until no more cyanide is detected in the sewage flowing through the pipe or channel. The contaminated sewage in the storage tank may then be treated to remove the cyanide, or alternatively it may be dispersed slowly through the sewage works with the normal sewage so that the amount of cyanide passing through the works at any time is negligible.
The apparatus which has been developed for monitoring the sewage is illustrated diagrammatically in the accompanying drawings, and comprises a probe 1 formed by a tube 2 made of a flexible semi-permeable dialysis membrane, and a pair of rigid plastics tubular members 3 and 4 which are sealed into opposite ends of the tube 2 to form respectively an inlet and an outlet of the probe. In the present example the dialysis membrane from which the tube 2 is formed is made of cellulose having a pore size of 24 Angstrom units and a molecular weight cut off of 14000, and the probe is about 2.5 cms in diameter and approximately 1 5 cms long.
The inlet 3 of the probe 1 is connected via a line 5, a junction 6, and a pair of lines 7 and 8 to the outlets of a pair of pumps 9 and 10. The pump 9 is arranged to draw atmospheric air through a filter 11 and supply the air to the probe 1. The pump 10 is arranged to supply an aqueous solution of chloramine T to the probe 1 from a reservoir 12 of the solution. The inlet member 3 of the probe 1 contains a diffuser 13 in the form of a perforated plastics plate which extends across the member 3 so that the air and chloramine T solution supplied to the probe have to pass through the diffuser 13.
The outlet 4 of the probe 1 is connected via a line 14 to an analyser 1 5 which is sensitive to the presence of cyanogen chloride in the effluent received from the probe 1 along the line 14 and which is arranged to provide an electrical output signal 1 6 related to the concentration of cyanogen chloride in the effluent.
In more detail the analyser 1 5 comprises a reaction vessel 1 7 in which the effluent received through the line 14 from the probe 1 is reacted with barbituric acid in pyridine and hydrochloric acid. if there is any cyanogen chloride contained in the effluent, the liquid which is obtained from the reaction in the vessel 1 7 is coloured, ranging from pale red, through red, to violet, depending on the concentration of cyanogen chloride in the effluent.The liquid and gas from the reaction vessel 17 is passed via a line 18 to a container 19 in which the liquid and the gas are separated and in which the colour intensity of the liquid is measured by standard colourimetric techniques using a light source 20, an optical filter 20a which passes light having a wavelength only within a predetermined range covering the colour of interest (in the present case 540 to 610 n.m.), and a photometric sensor 21 which provides the output signal 1 6. The container 19 is sealed apart from an inlet at the top for connection to the line 18, and an outlet tube 22 which projects into the container 19 and which is adjustable in position to determine the level of liquid 23 which is allowed to settle in the container. The outlet 22 leads to waste.The opposite end faces 24 and 25 of the container 19 are parallel, transparent, and optically flat, and are arranged normally to the optical path 26 of the colourimeter so that the light beam projected from the source 20 towards the filter 20a and the photometric sensor 21 passes through the liquid 23 which is settled in the container 1 9.
In operation the probe 1 is placed into the sewage
27 flowing through the pipe or channel 28 to be
monitored so that the probe 1 is vertical with its
inlet 3 at the bottom. The analyser 1 5 and the
pumps 9, 10 for supplying the air and the
chloramine T solution to the probe 1 are located
in any desired suitable location outside the pipe or
channel 28. With the pumps 9 and 10 in operation, a mixture of air and chloramine T solution is pumped into the probe 1 through the inlet 3. The semi-permeable membrane tube 2 fills with the chloramine T solution and the air bubbles upwardly rapidly through the solution, a good distribution of small air bubbles being obtained by means of the diffuser 13 located in the inlet member 3.When the tube 2 is filled with the chloramine T solution, the pumps 9 and 10 are adjusted so that the rate of flow of air through the tube is from 50 to 100 ccs per minute, and the rate of flow of chloramine T is reduced to an amount which is just sufficient to keep the solution in the tube 2 topped up, very little of the solution being carried over to the analyser 1 5 by the air leaving the probe 1 through the outlet line
14.
Ifthere is any cyanide present in the sewage 27 flowing past the probe 1 in the pipe or channel 28, cyanide ions will permeate into the tube 2 through its membrane wall, and in the tube 2 will react with the chloramine T to produce cyanogen chloride. Cyanogen chloride is a gas and is carried rapidly out of the tube 2 by the air which bubbles upwardly through the chloramine T solution. As mentioned earlier, if there is any cyanogen chloride in the effluent passing to the analyser 1 5 from the probe 1 along the line 14, this will cause the liquid leaving the reaction vessel 1 7 to be coloured red.The colour intensity of this liquid 23, which collects in the container 19, is measured by the colourimeter 20, 20a, 21, and the resulting electrical output signal 1 6 is related to the colour intensity of the liquid. This signal 1 6 is therefore dependent upon the amount of cyanogen chloride in the effluent received by the analyser 1 5 from the probe 1, and hence is also related to the amount of cyanide in the sewage flowing by the probe. The signal 1 6 is used to trip a relay (not shown) and sound an alarm, whereupon the entry of the sewage pipe or channel 28 into the sewage works is closed and the flow diverted as necessary. If desired however, this may be effected automatically in response to the signal 1 6 from the colourimeter.
Although the present invention has been developed primarily to detect the presence of cyanide in sewage, it should be remembered that by suitably selecting the semi-permeable membrane, the collecting medium, and the analyser, the invention can also be used for the detection of other substances, such as ammonia, nitrates, phosphates, phenol, and many others.
For example, the presence of ammonia in a bulk fluid such as mixed liquor (activated sludge) may be detected by passing a solution of hydrogen chloride as the collecting medium through a probe similar to that used in the above example except that the membrane tube is supported internally by a filling of loose glass beads. The collecting medium leaving the probe may be passed to an analyser in which the medium is mixed with phenol, sodium hydroxide, and sodium hypochlorite in the presence of potassium ferrocyanide as a catalyst, and if there is any ammonia in the collecting medium the liquid obtained will be coloured blue. This may be measured colourimetrically in the same way as in the above example. Alternatively the collecting medium leaving the probe may be analysed simply by mixing it with sodium hydroxide and measuring the liberated ammonia using a commercially available ammonia gas sensor.
Claims (17)
1. A method of detecting the presence of a specific substance in a bulk fluid comprising immersing directly in the bulk fluid a tube at least part of which is formed by a membrane which is permeable to the specific substance, the membrane being exposed to the bulk fluid and the tube containing a collecting medium which collects ions or molecules of the specific substance which permeate through the membrane into the tube from the bulk fluid, and testing the contents of the tube for the presence of the specific substance or a specific reaction product thereof.
2. A method according to claim 1, in which the collecting medium is passed through the tube so that the specific substance or the specific reaction product thereof is removed from the tube by the collecting medium, and the collecting medium is tested after it has left the tube.
3. A method according to claim 2, in which the collecting medium comprises a reactant which reacts with the specific substance which permeates into the tube to form the specific reaction product, and a carrier fluid for conducting at least the reaction product from the tube.
4. A method according to claim 2 or claim 3, in which the specific substance is a gas or produces a gaseous reaction product, the collecting
medium comprises a mixture of a gas and a liquid, and the tube is immersed vertically in the bulk fluid so that the gaseous component of the
collecting medium is caused to bubble rapidly
upwards through the tube to remove with it the specific substance or the reaction product.
5. A method according to claim 3 or claim 4, in which the specific substance to be detected is
cyanide, and the collecting medium comprises air
as the carrier fluid and chloramine T as the
reactant, the collecting medium leaving the tube
being tested for the presence of cyanogen
chloride formed by the reaction in the tube
between the chloramine T and any cyanide
permeating into the tube from the bulk fluid.
6. A method according to claim 5, in which the
collecting medium leaving the tube is tested by
reacting the medium with barbituric acid in
pyridine and hydrochloric acid whereby the presence of cyanogen chloride in the medium leaving the tube is indicated by a red colouring in the liquid obtained from the reaction.
7. A method according to claim 5 or claim 6, in which the tube is immersed in the sewage flowing through a pipe or channel leading to a sewage works, and the entry of sewage from the pipe or channel into the sewage works is shut off upon the detection of cyanogen chloride in the medium leaving the tube.
8. Apparatus for detecting the presence of a specific substance in a bulk fluid by the method according to claim 1, the apparatus comprising a probe including a tube having at least part of its wall formed by a membrane which is permeable to the specific substance, the probe also having an inlet and an outlet, means for connecting the inlet to a supply of a collecting medium, a pump for causing the collecting medium to flow through the probe, the inlet and the outlet being arranged so that the collecting medium flows along substantially the whole length of the tube, and an analyser which is connected to receive the collecting medium from the probe and which is sensitive to the presence of the specific substance or a specific reaction product thereof in the collecting medium.
9. Apparatus according to claim 8, in which the tube wall is formed entirely by the semipermeable membrane.
10. Apparatus according to claim 8 or claim 9, in which the semi-permeable membrane is made of cellulose.
11. Apparatus according to any one of claims 8 to 10, in which the pump is located upstream from the probe so that the collecting medium is supplied to the tube at a slight positive pressure.
12. Apparatus according to claim 11, in which the collecting medium is intended to comprise a mixture of fluids, and a separate pump is provided for supplying each of the fluid components of the collecting medium to the probe.
13. Apparatus according to claim 11 or claim 12, when dependent on claim 9, in which the probe has no internal means for supporting the membrane tube, the tube being prevented from collapsing during use by means of the positive pressure of the collecting medium pumped through it.
14. Apparatus according to any one of claims 8 to 13, in which the probe includes a diffuser at its inlet end for ensuring that, when the collecting medium comprises a mixture of fluids, the different fluid components of the medium entering and flowing through the tube are well mixed or dispersed one within another.
1 5. Apparatus according to claim 14, in which the diffuser comprises a perforated plate extending across the inlet end of the tube.
1 6. Apparatus according to any one of claims 8 to 15, in which the analyser is arranged to provide an electrical output signal which is related to the amount of the specific substance or the amount of the specific reaction product contained in the collecting medium received from the probe.
1 7. Apparatus according to claim 16, in which the analyser comprises a colourimeter which is arranged to provide an electrical output signal which is dependent upon the colour of a liquid of which the colour is dependent upon the amount of the specific substance or specific reaction product in the collecting medium received from the probe.
18. Apparatus according to claim 17, in which the analyser comprises a container for the liquid of which the colour is to be sensed by the colourimeter, the container having a top inlet for the entry of the liquid, an outlet tube which projects into the container and which is adjustable in position so that any gas can be separated from the liquid and a substantially stable liquid level can be established in the container, and parallel, optically flat, transparent end faces in the optical path of the colourimeter.
19. Apparatus according to claim 8, substantially as described with reference to the accompanying drawings.
20. A method according to claim 1, substantially as described with reference to the accompanying drawings.
New Claims or Amendments to Claims filed on 3
March 1980.
Superseded Claims 1 to 20.
New or Amended Claims:
1. A method of detecting the presence of a specific substance in sewage or other complex liquids resulting from the treatment of sewage, the method comprising immersing directly in the complex liquid a tube at least part of which is formed by a membrane which is permeable to the specific substance, the membrane being exposed to the complex liquid, passing a reactant into the tube so that the reactant contacts the inside surface of the membrane and reacts with ions or molecules of the specific substance which permeate through the membrane into the tube from the complex liquid to form a specific reaction product, collecting the fluid leaving the tube, and testing this effluent for the presence of the specific reaction product.
2. A method according to claim 1, in which the reactant is passed into the tube with a carrier fluid, and the fluid leaving the tube consists of the carrier fluid and at least the specific reaction product which may have been formed in the tube.
3. A method according to claim 2, in which the specific reaction product is gaseous, the carrier fluid is a gas, and the reactant is a liquid, the tube being immersed vertically in the complex liquid so that the carrier gas is caused to bubble rapidly upwards through the liquid reactant in the tube to remove with it the specific reaction product.
4. A method according to claim 3, in which the specific substance to be detected is cyanide, the carrier fluid is air, and the reactant is chloramine
T, the fluid leaving the tube being tested for the presence of cyanogen chloride formed by the reaction in the tube between the chloramine T and any cyanide permeating into the tube from the complex liquid.
5. A method according to claim 4, in which the fluid leaving the tube is tested by reacting it with barbituric acid in pyridine and hydrochloric acid whereby the presence of cyanogen chloride in the fluid is indicated by a red colouring in the liquid obtained from the reaction.
6. A method according to claim 4 or claim 5, in which the tube is immersed in the sewage flowing through a pipe or channel leading to a sewage works, and the entry of sewage from the pipe or channel into the sewage works is shut off upon the detection of cyanogen chloride in the fluid leaving the tube.
7. Apparatus for detecting the presence of a specific substance in sewage or another complex liquid resulting from the treatment of sewage, the apparatus comprising a probe which is immersed in the complex liquid and which includes a tube formed by a membrane which is permeable to the specific substance, the external surface of the membrane being exposed to the complex liquid, means connecting an inlet of the probe to a supply of a carrier fluid and to a supply of a reactant which will react with the specific substance to produce a specific reaction product, means for continuously pumping the carrier fluid and the reactant into the probe, the probe having an outlet arranged so that the mixture of the carrier fluid and the reactant will fill the tube before the fluid leaves the probe through the outlet, and an analyser which is connected to receive the fluid which leaves the probe through the outlet, the analyser being sensitive to the presence of the specific reaction product in the fluid.
8. Apparatus according to claim 7, in which the semi-permeable membrane is made of cellulose.
9. Apparatus according to claim 7 or claim 8, in which the tube contains internal support means which prevents the membrane from collapsing but which will permit the reactant and the carrier fluid pumped into the probe to contact the internal surface of the membrane.
10. Apparatus according to any one of claims 7 to 9, in which the carrier fluid is a gas and the reactant is a liquid which will react with the specific substance to produce a gaseous product.
11. Apparatus according to any one of claims 7 to 10, in which the probe includes a diffuser at its inlet end for ensuring that the carrier fluid and the reactant flowing into the tube are well mixed or dispersed one within another.
12. Apparatus according to claim 11, in which the diffuser comprises a perforated plate extending across the inlet end of the tube.
1 3. Apparatus according to any one of claims 7 to 12, in which the analyser is arranged to provide an electrical output signal which is related to the amount of the specific reaction product contained in the fluid received from the probe.
14. Apparatus according to claim 13, in which the analyser comprises a colourimeter which is arranged to provide an electrical output signal which is dependent upon the colour of a liquid of which the colour is dependent upon the amount of the specific reaction product in the fluid received from the probe.
1 5. Apparatus according to claim 14, in which the analyser comprises a container for the liquid of which the colour is to be sensed by the colourimeter, the container having a top inlet for the entry of the liquid, an outlet tube which projects into the container and which is adjustable in position so that any gas can be separated from the liquid and a substantially stable liquid level can be established in the container, and parallel, optically flat, transparent end faces in the optical path of the colourimeter.
1 6. Apparatus according to claim 7, substantially as described with reference to the accompanying drawings.
17. A method according to claim 1, substantially as described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7932669A GB2034032B (en) | 1978-09-28 | 1979-09-20 | Detection of a specific substance in a bulk fluid |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7838520 | 1978-09-28 | ||
| GB7932669A GB2034032B (en) | 1978-09-28 | 1979-09-20 | Detection of a specific substance in a bulk fluid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2034032A true GB2034032A (en) | 1980-05-29 |
| GB2034032B GB2034032B (en) | 1982-12-22 |
Family
ID=26268997
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7932669A Expired GB2034032B (en) | 1978-09-28 | 1979-09-20 | Detection of a specific substance in a bulk fluid |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2034032B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0326995A2 (en) * | 1988-01-30 | 1989-08-09 | Fuji Electric Co., Ltd. | Method and apparatus for quantitative determination of trihalomethanes |
| WO1995033203A1 (en) * | 1994-05-27 | 1995-12-07 | Berman, Richard, J. | Method for quantitative analysis of total cyanide |
| WO2005033696A1 (en) * | 2003-09-30 | 2005-04-14 | Pml Applications Ltd. | Method for water testing and devices and kit of components for use in such a method |
| CN103901032A (en) * | 2014-04-16 | 2014-07-02 | 北京瑞升特科技有限公司 | Method and system for vaccine detection |
-
1979
- 1979-09-20 GB GB7932669A patent/GB2034032B/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0326995A2 (en) * | 1988-01-30 | 1989-08-09 | Fuji Electric Co., Ltd. | Method and apparatus for quantitative determination of trihalomethanes |
| EP0326995A3 (en) * | 1988-01-30 | 1990-06-13 | Fuji Electric Co., Ltd. | Method and apparatus for quantitative determination of trihalomethanes |
| WO1995033203A1 (en) * | 1994-05-27 | 1995-12-07 | Berman, Richard, J. | Method for quantitative analysis of total cyanide |
| WO2005033696A1 (en) * | 2003-09-30 | 2005-04-14 | Pml Applications Ltd. | Method for water testing and devices and kit of components for use in such a method |
| CN103901032A (en) * | 2014-04-16 | 2014-07-02 | 北京瑞升特科技有限公司 | Method and system for vaccine detection |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2034032B (en) | 1982-12-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |