CA1337246C - Method for measuring a gas content or metal content of a bath of liquid metal and probe used in said method - Google Patents
Method for measuring a gas content or metal content of a bath of liquid metal and probe used in said methodInfo
- Publication number
- CA1337246C CA1337246C CA000590037A CA590037A CA1337246C CA 1337246 C CA1337246 C CA 1337246C CA 000590037 A CA000590037 A CA 000590037A CA 590037 A CA590037 A CA 590037A CA 1337246 C CA1337246 C CA 1337246C
- Authority
- CA
- Canada
- Prior art keywords
- gas
- probe
- bath
- line
- sealed
- 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.)
- Expired - Lifetime
Links
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
- G01N33/20—Metals
- G01N33/202—Constituents thereof
- G01N33/2022—Non-metallic constituents
- G01N33/2025—Gaseous constituents
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
Carrier gas is pumped in the gas supply line of a probe which contains a gas supply line sealed by a fusible stopper and a gas removal line. The probe is immersed in the bath of liquid metal and as soon as the pressure drops at the melting away of the stopper and consequently the opening of the gas supply line is determined, the measuring cyclus is started, the lines are first flushed with carrier gas and then said carrier gas is pumped by the pump through the probe, the circuit and the katharometer.
Description
"Method for measuring a gas content or metal content of a bath of liquid metal and probe used in said method".
The invention relates to a method for measuring a gas content or metal content of a bath of liquid metal according to which a probe which contains a gas supply line and a gas removal line, the lowermost ends of which are situated near each other, is immersed in the bath of liquid metal, a carrier gas is supplied to the gas supply line, said carrier gas is collected again in the course of the measuring cycle either after picking up from the bath the gas whose content has to be measured, or after picking up fine particles of the metal of the bath, and it is fed via the gas removal line through a measuring device in which the gas content or the metal content is measured.
A method of this type for measuring the hydrogen content of a steel bath has been described in the Belgian Patent No. 1,004,013 of November 22, 1988 by the Applicant.
In this method use is made of a throw-away probe which is installed on a lance and is subsequently immersed in the bath.
Said throw-away probe has a limited residence time in the bath so that the measuring cycle, which may, for example, begin with flushing the gas lines before the carrier gas is pumped around through the gas detector and, consequently, the actual measurement begins, has therefore to be carried out fairly rapidly after the immersion.
In said known method it may therefore happen that the actual measuring cycle is started too early or too late.
The invention relates to a method for measuring a gas content or metal content of a bath of liquid metal according to which a probe which contains a gas supply line and a gas removal line, the lowermost ends of which are situated near each other, is immersed in the bath of liquid metal, a carrier gas is supplied to the gas supply line, said carrier gas is collected again in the course of the measuring cycle either after picking up from the bath the gas whose content has to be measured, or after picking up fine particles of the metal of the bath, and it is fed via the gas removal line through a measuring device in which the gas content or the metal content is measured.
A method of this type for measuring the hydrogen content of a steel bath has been described in the Belgian Patent No. 1,004,013 of November 22, 1988 by the Applicant.
In this method use is made of a throw-away probe which is installed on a lance and is subsequently immersed in the bath.
Said throw-away probe has a limited residence time in the bath so that the measuring cycle, which may, for example, begin with flushing the gas lines before the carrier gas is pumped around through the gas detector and, consequently, the actual measurement begins, has therefore to be carried out fairly rapidly after the immersion.
In said known method it may therefore happen that the actual measuring cycle is started too early or too late.
- 2 - t 337246 The same applies not only to the measurement of a gas content but, for example, also to the measurement of a metal content in which, therefore, fine metal particles, which are liberated from the bath, for example by means of electrodes or by injecting the carrier gas at high speed into the metal bath, are passed along with the carrier gas to a measuring device for measuring the quantity of a metal in the carrier gas.
The object of the invention is to remedy this disadvantage and to provide a method for measuring a gas content or a metal content of a bath of liquid metal, the measuring cycle always being carried out at the required instant.
For this purpose, a probe is used of which at least one of the gas lines is sealed by a seal which is opened immediately after immersion of the probe in the bath, before said sealed end is opened, pumping is carried out into the gas line which has said end or pumping is carried out from said line, the sudden pressure or flow-rate change is then detected when the sealed end is opened, and the measuring cycle is started immediately after said pressure or flow-rate change and the carrier gas is therefore fed through the probe.
In a particular embodiment of the invention, the measuring device is calibrated at said sudden pressure or flow-rate change.
Immediately after the change has been detected, the carrier gas can be fed via the gas removal line to the measuring device in order to measure the gas content or metal content.
In a remarkable embodiment, the measuring cycle is , however, started with a flushing of the line, the carrier gas being fed through the gas lines and allowed to escape and carrier gas only thereafter being fed through the probe and through the measuring device for the actual measurement.
During the flushing carrier gas may be fed simul-taneously into the gas supply line and the gas removal line, the carrier gas being allowed to escape into s the bath.
Carrier gas can also be fed to one of the gas lines of the probe during the flushing and it can be removed via the other gas line in the probe and allowed to escape into the open atmosphere.
During the actual measurement, the carrier gas is pr~ferably pumped in a closed circuit through the probe and the measuring device.
In another embodiment a gas content is measured and the carrier gas which is allowed to flow through the probe during 15 the actual measurement is dried.
The invention also relates to a probe which is obviously suitable for applying the method according to one of the preceding embodiments.
The invention therefore relates to a probe for measuring a gas content or a metal content of a bath of liquid metal, which probe has a gas supply line, which debouches with an end on the end of the probe designed to be situated at the bottom, and a gas removal line for collecting the carrier gas, which flows out of the gas supply line, and the end of which is situated in the vicinity of the lowermost end of the gas supply line and which probe is characterized in that at least one of the gas lines is sealed by a seal which can be removed during the immersion.
In a particular embodiment of the invention, the lowermost end of the gas supply line is sealed.
_3a _ 1 3 3 7 2 4 6 In a re~arkable embodiment of the invention, the sealed end of the gas line is sealed by a fusible plug which melts on immersion in the metal bath.
Other features and advantages of the invention will emerge from the description, which follows below, of a method for measuring a gas content or metal content of a bath of liquid metal and of a probe used therein ~ 4 - I 33 7246 according to the invention; this description is given solely as an example and does not restrict the invention;
the reference numerals relate to the accompanying drawings.
Figure 1 represents a block diagram of a device for measuring a gas content of liquid metal according to the invention.
Figure 2 is partly a section and partly a front view of the probe from the device according to figure 1.
In the two figures, the same reference numerals relate to the same elements.
The device according to figure 1 is a device for measuring the hydrogen content in liquid metal.
Said device contains essentially a probe 1 a gas circuit 2, which connect with both ends to the probe and in which a filter 4, a katharometer 5, a pump 6, a four-way stopcock 7, a pressure gauge 38, and a flow meter 8 are installed consecutively in the flow direction of the gas which is indicated in figure 1 by the arrow The probe 1 is a throw-away probe which is con-nected by means of a quick-connection coupling 9, 10 detachably to a lance 11 through which ends of the gas circuit 2 extend, and which is connected by means of the same quick-connection coupling 9, 10 to said two ends of the circuit 2.
A bottle 12 containing pressurized nitrogen is connected by means of a supply line 13 to the four-way stopcock 7.
Said four-way stopcock 7 closes, in one position, the gas circuit 2, the supply line 13 being connected to the open atmosphere. The bottle 12 is, of course, then closed. In another position, the four-way stopcock interrupts the gas circuit 2 and it connects, on the one hand, the supply line 13 to the section of the gas circuit 2 which connects to the probe 1 via the pressure gauge 38 and the flow meter 8 and it connects, on the other hand, the section of the gas circuit 2 which comes from the pump 6 to the open atmosphere.
The katharometer 5 is also of a construction known per se and is not described in detail here. Said katha-rometer determines the hydrogen content of the inert carrier gas by measuring the thermal conductivity of the gas . It is coupled to a microprocessor 39 which is controlled by, inter alia, the pressure gauge 38 and/or the flow meter 8.
The probe 2 contains, as depicted in figure 2, at one end a gas collection section which is formed by a bell 14 of porous refractory stone and at the other end, one section 9 of the quick-connection coupling 9, 10 mentioned above.
The opening of the bell 14 is directed away from the section 9 and the bell is held at a distance from said section 9 by a quartz tube 15, to the ends of which the bell 14 and the section 9 are attached by means of the cement 16.
Extending axially through the quartz tube 15 is a narrow quartz tube 17 which, on the one hand, projects into the section 9 and, on the other hand, extends through the bell 14 and is attached to said bell 14 with cement.
A limb of a narrower narrow quartz tube 18, bent through 180, is attached by mens of the cement 19 in the open end of the narrow quartz tube 17 extending outside the bell 14. The other limb of said narrow quartz tube 18 is directed with its free end towards the opening of the bell 14. Said end is sealed by a plug 40 of a material which melts at the temperature of the steel bath. The cement 19 seals the narrow tube 17 around the narrow tube 18 in a gastight manner.
In the quartz tube 15, the narrow quartz tube 17 is additionally surrounded by a tube 20 of A12O3.
The end of the quartz tube 15 remote from the bell 14 and especially the section 9 of the quick-con-nection coupling 9, 10 are surrounded by a sheath con-sisting of three concentric tubes adjacent to eachother, namely an innermost tube 21 of paperboard, a middlemost tube 22 of paperboard and an outermost tube 23 of resin-bonded sand.
The tubes 22 and 23 of said sheath are attached to the quartz tube 15 by means of cement 24.
The sheath 21, 22, 23 extends at the side facing away from the bell 14 to appreciably beyond the section 9. The inside diameter of the innermost tube 21 cor-responds to the outside diameter of the lance 11 whose end projects into said sheath when the lance is connected to the probe 1.
The sheath 21, 22, 23 forms a thermal shield for this lowermost end of the lance 11 and particularly for the quick-connection coupling 9, 10.
As is especially evident from figure 2, the section 9 of the quick-connection coupling 9, 10 consists of a body which, on the immersion side, i.e. the side directed towards the bell 14, is provided with a collar 25 in which the quartz tube 15 is secured and is centrally provided with a-hole 26 into which the end of the quartz tube 17 projects.
An axial hole 27, which connects to the hole 26 and forms a gas supply line together with the quartz tubes 17 and 18, extends through said body.
Next to the axial hole 27, there extends through the body of the section 9 four holes 28 which debouch into the space between the quartz tube 15 and the narrow quartz tube 17 and which together with the last-mentioned space form a gas removal line which is sealed on the immersion side by the porous bell 14 which forms a diaphragm, allows gas through but holds back liquid metal.
- -The diameter of the body of the section 9 of the quick-connection coupling 9, 10 decreases stepwise in the direction facing away from the quartz tube 15 and, specifically, in a manner such that three inwardly indented collars 29, 30 and 31 are formed.
The innermost tube 21 of the sheath 21, 22, 23 is up against the collar 29 situated most outwardly and nearest the quartz tube 15 and is also up against the outside of the cylindrical section of the section 9 which is situated between the collars 29 and 30.
The section of the body with a smaller diameter which is situated between the collars 30 and 31 is surrounded by an O-ring 32 partly recessed therein.
The abovementioned holes 28 debouch in the collar 31.
The cylindrical section extending outside the collar 31 is also surrounded by an O-ring 33 partly recessed therein.
The collars 30 and 31 and the O-rings 32 and 33 interact with parts of the section 10 of the quick-connection coupling 9, 10, which section 10 forms a piece which is installed on the end of the lance 11.
This section 10 is provided at its end with an axial circular hole 34 into which the cylindrical section, situated between the collars 30 and 31, of the section 9 fits and is provided with a smaller axial hole 35 which, on the one hand, debouches at the base of the hole 34 and, on the other hand, connects to the end of the gas circuit 2 which is situated downstream of the flow meter 8.
Around the hole 35 there extends, in the section 10, a channel 36 which, on the one hand, debouches at the base of the hole 34 and, on the other hand, connects to the other end of the gas circuit 2 which just like the previous end, is attached in said section 10 .
These two ends of the gas circuit therefore extend through the metal lance 11.
In the smallest hole 35 of the section 10 of the quick-connection coupling 9, 10 there is attached a mechanical connecting piece 37 which has four sprung legs provided at their ends with thicker parts which, when the lance 11 is pushed into the sheath 21, 22, 23, snap in a sprungmanner over the thickened head on the end of the section of the section 9 projecting outside the collar 31.
The connecting piece 37 is provided with a channel so that the hole 35 remains in communication with the end of the circuit 2.
The entity formed by the quartz tube 15 with pos-sibly the bell 14, the projecting end of the narrowquartz tube 17 and the narrow quartz tube 18 may also be surrounded by a cap of metal which, for the sake of simplicity, is not depicted in the figures and is attached to the sheath 21, 22, 23 and which is surrounded by a cap of paperboard, likewise not shown in the figures.
To carry out a measurement, a probe 1 is installed by means of the quick-connection coupling 9, 10 on a lance 11, which lance is therefore pushed into the sheath 21, 22, 23 of the probe 1.
The four-way stopcock 7 is set in the position in which the supply line 13 connects to the gas circuit 2 so that nitrogen flows from the bottle 12 to the probe 1.
Because the lowermost end of the gas supply line 17, 18, 27 is sealed by the fusible plug 40, gas will no longer flow once said line has been filled and a relatively high pressure, which corresponds to the pressure of the gas bottle 12, will prevail in said line.
In the gas removal line 14, 15, 28 there is no carrier gas and the katharometer 5 is out of operation.
The probe 1 is now immersed in the bath of liquid metal.
The stopper 40 melts immediately as a result of the temperature of said bath.
As a result of this, the carrier gas is able to flow out of the gas supply line 17,18,27 into the bath, as a result of which the flow-rate meter 8 suddenly indicates a flow-rate and the pressure gauge 38 sudden-ly indicates a low pressure.
This sudden flow-rate and pressure change is trans-mitted to the microprocessor 39 which, as a consequence of the pressure change and/or flow-rate change, in the first place calibrates the katharometer 5 and then sets it in operation in order to start the measuring cycle.
The beginning of the measuring cycle is formed by a flushing of the gas lines in order to remove impuri-ties which are liberated by the sudden heating of the components of the probe.
During said flushing, nitrogen bubbles out of the narrow quartz tube 18, which nitrogen is collected by the bell 14 and is drawn off through said bell by the pump 6, which has been set in operation in the meantime, via the gas removal line 14, 15 , 28 and the circuit 2.
At the position of the four-way stopcock this gas which is drawn off is released to the atmosphere.
Ten seconds after the first detection of impurities by the katharometer 5, the four-way stopcock 7 is set in the other position, namely the position shown in figure 1, either manually or automatically.
The actual measurement now begins, the nitrogen gas present in the gas circuit 2 being pumped around by the pump 6 in said circuit 2 and through the probe 1.
During the bubbling through the liquid metal,an exchange takes place with the gases present in the liquid metal.
After a short time, an equilibrium is approached and, consequently, the concentration of hydrogen in the carrier gas in the circuit 2 is a measure of the concentration of hydrogen in the liquid metal.
The katharometer 5 then shows the hydrogen content in the bath.
In a variant of the method described above, a probe 1 is used, of which not only the gas supply line 17, 18, 27 , but also the gas removal line 14, 15, 28 is sealed in an airtight manner at the lowermost end by a plug which melts on immersion in the bath.
Because the bell 14 is porous, said seal should then be provided at the lowermost end of the quartz tube 15.
The same device as figure 1 is used in that case, but the four-way stopcock 7 is replaced by a more com-plicated distribution device so that, before the immer-sion, pressurized nitrogen from the gas bottle 12 is fed via both sections of the circuit both to the gas supply line 17, 18, 27 and to the gas removal line and, more particularly, the section 15,28 thereof.
As soon as the probe 1 is immersed, not only the abovementioned plug 40 melts, but also the plug in the narrow quartz tube 15.
The sudden flow-rate or pressure change which is produced when the plugs melt away is measured and immediately after said changes, the position of the distribution valve is changed and the operation of the katharometer 5 is started via the microprocessor 39 and the measuring cycle is therefore started as in the embodiment described above.
In this variant, the microprocessor 39 can be controlled by a pressure gauge 38 which is installed in the section of the circuit 2 which connects to the gas removal line 15,28. Said pressure gauge may in that case be incorporated in the katharometer it-self.
In yet another embodiment of the method the pro-cedure is as in the variant described above, but the position of the distribution valve is not changed immedia-tely when the sudden flow-rate or pressure change occurs when the plugs in the gas lines 14, 15, 28 and 17, 18,27 melt away.
The flushing at the beginning of the measuring cycle is therefore carried out both by carrier gas which is blown through the flow-rate meter 8, a section of the circuit 2 and the gas supply line 17, 18, 27 into the metal bath and by carrier gas which is also blown into the metal bath via the rest of the circuit 2, through the pump 6, which may possibly facilitate the flow of the carrier gas by rotating in the required direction, and the gas removal line 14, 15, 28.
Ten seconds after this blowing, the position of the distribution valve is in fact changed and the carrier gas is then fed in a closed circuit through the circuit 2 and the probe 1 and the actual measurement by the katharometer 5 therefore takes place.
In all the embodiments described above, the measure-ment takes place at the correct instant so that the measurement is always terminated before the probe 1 is destroyed by the heat of the metal bath.
The invention is by no means restricted to the embodiments described above and, within the scope of the patent application, many changes can be made to the embodiments described in relation to the shape, the construction, the arrangement, and the number of components which are used to implement the invention.
In particular, in the lastmentioned variant in which carrier gas is passed through the gas supply line and the gas removal line of the probe into the bath during the flushing, it is not essential for both gas lines of the probe to be closed before immersion in the metal bath. It is sufficient that one of the two lines is closed and the pressure or the flow-rate change in said line causes the flushing of the measuring cycle to start through the agency of the microprocessor.
The object of the invention is to remedy this disadvantage and to provide a method for measuring a gas content or a metal content of a bath of liquid metal, the measuring cycle always being carried out at the required instant.
For this purpose, a probe is used of which at least one of the gas lines is sealed by a seal which is opened immediately after immersion of the probe in the bath, before said sealed end is opened, pumping is carried out into the gas line which has said end or pumping is carried out from said line, the sudden pressure or flow-rate change is then detected when the sealed end is opened, and the measuring cycle is started immediately after said pressure or flow-rate change and the carrier gas is therefore fed through the probe.
In a particular embodiment of the invention, the measuring device is calibrated at said sudden pressure or flow-rate change.
Immediately after the change has been detected, the carrier gas can be fed via the gas removal line to the measuring device in order to measure the gas content or metal content.
In a remarkable embodiment, the measuring cycle is , however, started with a flushing of the line, the carrier gas being fed through the gas lines and allowed to escape and carrier gas only thereafter being fed through the probe and through the measuring device for the actual measurement.
During the flushing carrier gas may be fed simul-taneously into the gas supply line and the gas removal line, the carrier gas being allowed to escape into s the bath.
Carrier gas can also be fed to one of the gas lines of the probe during the flushing and it can be removed via the other gas line in the probe and allowed to escape into the open atmosphere.
During the actual measurement, the carrier gas is pr~ferably pumped in a closed circuit through the probe and the measuring device.
In another embodiment a gas content is measured and the carrier gas which is allowed to flow through the probe during 15 the actual measurement is dried.
The invention also relates to a probe which is obviously suitable for applying the method according to one of the preceding embodiments.
The invention therefore relates to a probe for measuring a gas content or a metal content of a bath of liquid metal, which probe has a gas supply line, which debouches with an end on the end of the probe designed to be situated at the bottom, and a gas removal line for collecting the carrier gas, which flows out of the gas supply line, and the end of which is situated in the vicinity of the lowermost end of the gas supply line and which probe is characterized in that at least one of the gas lines is sealed by a seal which can be removed during the immersion.
In a particular embodiment of the invention, the lowermost end of the gas supply line is sealed.
_3a _ 1 3 3 7 2 4 6 In a re~arkable embodiment of the invention, the sealed end of the gas line is sealed by a fusible plug which melts on immersion in the metal bath.
Other features and advantages of the invention will emerge from the description, which follows below, of a method for measuring a gas content or metal content of a bath of liquid metal and of a probe used therein ~ 4 - I 33 7246 according to the invention; this description is given solely as an example and does not restrict the invention;
the reference numerals relate to the accompanying drawings.
Figure 1 represents a block diagram of a device for measuring a gas content of liquid metal according to the invention.
Figure 2 is partly a section and partly a front view of the probe from the device according to figure 1.
In the two figures, the same reference numerals relate to the same elements.
The device according to figure 1 is a device for measuring the hydrogen content in liquid metal.
Said device contains essentially a probe 1 a gas circuit 2, which connect with both ends to the probe and in which a filter 4, a katharometer 5, a pump 6, a four-way stopcock 7, a pressure gauge 38, and a flow meter 8 are installed consecutively in the flow direction of the gas which is indicated in figure 1 by the arrow The probe 1 is a throw-away probe which is con-nected by means of a quick-connection coupling 9, 10 detachably to a lance 11 through which ends of the gas circuit 2 extend, and which is connected by means of the same quick-connection coupling 9, 10 to said two ends of the circuit 2.
A bottle 12 containing pressurized nitrogen is connected by means of a supply line 13 to the four-way stopcock 7.
Said four-way stopcock 7 closes, in one position, the gas circuit 2, the supply line 13 being connected to the open atmosphere. The bottle 12 is, of course, then closed. In another position, the four-way stopcock interrupts the gas circuit 2 and it connects, on the one hand, the supply line 13 to the section of the gas circuit 2 which connects to the probe 1 via the pressure gauge 38 and the flow meter 8 and it connects, on the other hand, the section of the gas circuit 2 which comes from the pump 6 to the open atmosphere.
The katharometer 5 is also of a construction known per se and is not described in detail here. Said katha-rometer determines the hydrogen content of the inert carrier gas by measuring the thermal conductivity of the gas . It is coupled to a microprocessor 39 which is controlled by, inter alia, the pressure gauge 38 and/or the flow meter 8.
The probe 2 contains, as depicted in figure 2, at one end a gas collection section which is formed by a bell 14 of porous refractory stone and at the other end, one section 9 of the quick-connection coupling 9, 10 mentioned above.
The opening of the bell 14 is directed away from the section 9 and the bell is held at a distance from said section 9 by a quartz tube 15, to the ends of which the bell 14 and the section 9 are attached by means of the cement 16.
Extending axially through the quartz tube 15 is a narrow quartz tube 17 which, on the one hand, projects into the section 9 and, on the other hand, extends through the bell 14 and is attached to said bell 14 with cement.
A limb of a narrower narrow quartz tube 18, bent through 180, is attached by mens of the cement 19 in the open end of the narrow quartz tube 17 extending outside the bell 14. The other limb of said narrow quartz tube 18 is directed with its free end towards the opening of the bell 14. Said end is sealed by a plug 40 of a material which melts at the temperature of the steel bath. The cement 19 seals the narrow tube 17 around the narrow tube 18 in a gastight manner.
In the quartz tube 15, the narrow quartz tube 17 is additionally surrounded by a tube 20 of A12O3.
The end of the quartz tube 15 remote from the bell 14 and especially the section 9 of the quick-con-nection coupling 9, 10 are surrounded by a sheath con-sisting of three concentric tubes adjacent to eachother, namely an innermost tube 21 of paperboard, a middlemost tube 22 of paperboard and an outermost tube 23 of resin-bonded sand.
The tubes 22 and 23 of said sheath are attached to the quartz tube 15 by means of cement 24.
The sheath 21, 22, 23 extends at the side facing away from the bell 14 to appreciably beyond the section 9. The inside diameter of the innermost tube 21 cor-responds to the outside diameter of the lance 11 whose end projects into said sheath when the lance is connected to the probe 1.
The sheath 21, 22, 23 forms a thermal shield for this lowermost end of the lance 11 and particularly for the quick-connection coupling 9, 10.
As is especially evident from figure 2, the section 9 of the quick-connection coupling 9, 10 consists of a body which, on the immersion side, i.e. the side directed towards the bell 14, is provided with a collar 25 in which the quartz tube 15 is secured and is centrally provided with a-hole 26 into which the end of the quartz tube 17 projects.
An axial hole 27, which connects to the hole 26 and forms a gas supply line together with the quartz tubes 17 and 18, extends through said body.
Next to the axial hole 27, there extends through the body of the section 9 four holes 28 which debouch into the space between the quartz tube 15 and the narrow quartz tube 17 and which together with the last-mentioned space form a gas removal line which is sealed on the immersion side by the porous bell 14 which forms a diaphragm, allows gas through but holds back liquid metal.
- -The diameter of the body of the section 9 of the quick-connection coupling 9, 10 decreases stepwise in the direction facing away from the quartz tube 15 and, specifically, in a manner such that three inwardly indented collars 29, 30 and 31 are formed.
The innermost tube 21 of the sheath 21, 22, 23 is up against the collar 29 situated most outwardly and nearest the quartz tube 15 and is also up against the outside of the cylindrical section of the section 9 which is situated between the collars 29 and 30.
The section of the body with a smaller diameter which is situated between the collars 30 and 31 is surrounded by an O-ring 32 partly recessed therein.
The abovementioned holes 28 debouch in the collar 31.
The cylindrical section extending outside the collar 31 is also surrounded by an O-ring 33 partly recessed therein.
The collars 30 and 31 and the O-rings 32 and 33 interact with parts of the section 10 of the quick-connection coupling 9, 10, which section 10 forms a piece which is installed on the end of the lance 11.
This section 10 is provided at its end with an axial circular hole 34 into which the cylindrical section, situated between the collars 30 and 31, of the section 9 fits and is provided with a smaller axial hole 35 which, on the one hand, debouches at the base of the hole 34 and, on the other hand, connects to the end of the gas circuit 2 which is situated downstream of the flow meter 8.
Around the hole 35 there extends, in the section 10, a channel 36 which, on the one hand, debouches at the base of the hole 34 and, on the other hand, connects to the other end of the gas circuit 2 which just like the previous end, is attached in said section 10 .
These two ends of the gas circuit therefore extend through the metal lance 11.
In the smallest hole 35 of the section 10 of the quick-connection coupling 9, 10 there is attached a mechanical connecting piece 37 which has four sprung legs provided at their ends with thicker parts which, when the lance 11 is pushed into the sheath 21, 22, 23, snap in a sprungmanner over the thickened head on the end of the section of the section 9 projecting outside the collar 31.
The connecting piece 37 is provided with a channel so that the hole 35 remains in communication with the end of the circuit 2.
The entity formed by the quartz tube 15 with pos-sibly the bell 14, the projecting end of the narrowquartz tube 17 and the narrow quartz tube 18 may also be surrounded by a cap of metal which, for the sake of simplicity, is not depicted in the figures and is attached to the sheath 21, 22, 23 and which is surrounded by a cap of paperboard, likewise not shown in the figures.
To carry out a measurement, a probe 1 is installed by means of the quick-connection coupling 9, 10 on a lance 11, which lance is therefore pushed into the sheath 21, 22, 23 of the probe 1.
The four-way stopcock 7 is set in the position in which the supply line 13 connects to the gas circuit 2 so that nitrogen flows from the bottle 12 to the probe 1.
Because the lowermost end of the gas supply line 17, 18, 27 is sealed by the fusible plug 40, gas will no longer flow once said line has been filled and a relatively high pressure, which corresponds to the pressure of the gas bottle 12, will prevail in said line.
In the gas removal line 14, 15, 28 there is no carrier gas and the katharometer 5 is out of operation.
The probe 1 is now immersed in the bath of liquid metal.
The stopper 40 melts immediately as a result of the temperature of said bath.
As a result of this, the carrier gas is able to flow out of the gas supply line 17,18,27 into the bath, as a result of which the flow-rate meter 8 suddenly indicates a flow-rate and the pressure gauge 38 sudden-ly indicates a low pressure.
This sudden flow-rate and pressure change is trans-mitted to the microprocessor 39 which, as a consequence of the pressure change and/or flow-rate change, in the first place calibrates the katharometer 5 and then sets it in operation in order to start the measuring cycle.
The beginning of the measuring cycle is formed by a flushing of the gas lines in order to remove impuri-ties which are liberated by the sudden heating of the components of the probe.
During said flushing, nitrogen bubbles out of the narrow quartz tube 18, which nitrogen is collected by the bell 14 and is drawn off through said bell by the pump 6, which has been set in operation in the meantime, via the gas removal line 14, 15 , 28 and the circuit 2.
At the position of the four-way stopcock this gas which is drawn off is released to the atmosphere.
Ten seconds after the first detection of impurities by the katharometer 5, the four-way stopcock 7 is set in the other position, namely the position shown in figure 1, either manually or automatically.
The actual measurement now begins, the nitrogen gas present in the gas circuit 2 being pumped around by the pump 6 in said circuit 2 and through the probe 1.
During the bubbling through the liquid metal,an exchange takes place with the gases present in the liquid metal.
After a short time, an equilibrium is approached and, consequently, the concentration of hydrogen in the carrier gas in the circuit 2 is a measure of the concentration of hydrogen in the liquid metal.
The katharometer 5 then shows the hydrogen content in the bath.
In a variant of the method described above, a probe 1 is used, of which not only the gas supply line 17, 18, 27 , but also the gas removal line 14, 15, 28 is sealed in an airtight manner at the lowermost end by a plug which melts on immersion in the bath.
Because the bell 14 is porous, said seal should then be provided at the lowermost end of the quartz tube 15.
The same device as figure 1 is used in that case, but the four-way stopcock 7 is replaced by a more com-plicated distribution device so that, before the immer-sion, pressurized nitrogen from the gas bottle 12 is fed via both sections of the circuit both to the gas supply line 17, 18, 27 and to the gas removal line and, more particularly, the section 15,28 thereof.
As soon as the probe 1 is immersed, not only the abovementioned plug 40 melts, but also the plug in the narrow quartz tube 15.
The sudden flow-rate or pressure change which is produced when the plugs melt away is measured and immediately after said changes, the position of the distribution valve is changed and the operation of the katharometer 5 is started via the microprocessor 39 and the measuring cycle is therefore started as in the embodiment described above.
In this variant, the microprocessor 39 can be controlled by a pressure gauge 38 which is installed in the section of the circuit 2 which connects to the gas removal line 15,28. Said pressure gauge may in that case be incorporated in the katharometer it-self.
In yet another embodiment of the method the pro-cedure is as in the variant described above, but the position of the distribution valve is not changed immedia-tely when the sudden flow-rate or pressure change occurs when the plugs in the gas lines 14, 15, 28 and 17, 18,27 melt away.
The flushing at the beginning of the measuring cycle is therefore carried out both by carrier gas which is blown through the flow-rate meter 8, a section of the circuit 2 and the gas supply line 17, 18, 27 into the metal bath and by carrier gas which is also blown into the metal bath via the rest of the circuit 2, through the pump 6, which may possibly facilitate the flow of the carrier gas by rotating in the required direction, and the gas removal line 14, 15, 28.
Ten seconds after this blowing, the position of the distribution valve is in fact changed and the carrier gas is then fed in a closed circuit through the circuit 2 and the probe 1 and the actual measurement by the katharometer 5 therefore takes place.
In all the embodiments described above, the measure-ment takes place at the correct instant so that the measurement is always terminated before the probe 1 is destroyed by the heat of the metal bath.
The invention is by no means restricted to the embodiments described above and, within the scope of the patent application, many changes can be made to the embodiments described in relation to the shape, the construction, the arrangement, and the number of components which are used to implement the invention.
In particular, in the lastmentioned variant in which carrier gas is passed through the gas supply line and the gas removal line of the probe into the bath during the flushing, it is not essential for both gas lines of the probe to be closed before immersion in the metal bath. It is sufficient that one of the two lines is closed and the pressure or the flow-rate change in said line causes the flushing of the measuring cycle to start through the agency of the microprocessor.
Claims (16)
1. A method for measuring a gas content or metal content of a bath of liquid metal, according to which a probe which contains a gas supply line and a gas removal line, the lowermost ends of which are situated near each other, is immersed in the bath of liquid metal, a carrier gas is supplied to the gas supply line , and said carrier gas is collected again in the course of a measuring cycle either after picking up from the bath the gas whose content has to be measured, or after picking up fine particles of the metal of the bath, and is fed via the gas removal line through a measuring device in which the gas content or the metal content is measured, characterized in that a probe is used of which at least one of the gas lines is sealed by a seal which is opened immediately after immersion of the probe in the bath, before said sealed end is opened, pumping is carried out into the gas line which has said end or pumping is carried out from said line, the sudden pressure or flow-rate change is then detected when the end is opened, and the measuring cycle is started immediately after said pressure or flow-rate change and the carrier gas is therefore fed through the probe.
2. The method according to claim 1, characterized in that the measuring device is calibrated during said sudden pressure or flow-rate change.
3. The method according to claim 1, characterized in that the measuring cycle is started from a flushing of the lines, the carrier gas being fed through said gas lines and allowed to escape, and only thereafter is fed through the probe and through the measuring device for the actual measurement.
4. The method according to claim 3, characterized in that, during the flushing carrier gas is simultaneous-ly fed to the gas supply line and the gas removal line, the carrier gas being allowed to escape into the bath.
5. The method according to claim 3, characterized in that, during the flushing, carrier gas is fed to one of the gas lines of the probe and is removed via the other gas line in the probe and allowed to escape into the open atmosphere.
6. The method according to claim 3, characterized in that flushing is carried out for 1 to 10 seconds and only thereafter is the actual measurement started.
7. The method according to claim 1, characterized in that, during the actual measurement, the carrier gas is pumped in a closed circuit through the probe and the measuring device.
8. The method according to claim 1, characterized in that a probe is used, of which the lowermost end of the gas line is sealed by a fusible stopper which melts on immersion in the bath.
9. The method according to claim 8, characterized in that a probe is used, of which the gas supply line is sealed by a fusible stopper.
10. The method according to claim 1, characterized in that a probe is used, of which both gas lines in the probe are sealed in a gastight manner, before the immersion, for the carrier gas via a seal which is opened immediately after immersing the probe.
11. The method according to claim 1, characterized in that the gas line of the probe is sealed at its lowermost end.
12. The method according to claim 1, characterized in that a gas content is measured and the carrier gas which is allowed to flow through the probe during the actual measurement is dried.
13. A probe for measuring a gas content or a metal content of a bath of liquid metal, which probe has a gas supply line, an end of which debouches at the end of the probe designed to be situated in a bottom or lowermost position, and a gas removal line for collecting the gas, which flows out of the gas supply line and the end of which is situated in the vicinity of the lowermost end of the gas supply line, characterized in that at least one of the gas lines is sealed by a seal which can be removed during the immersion of the probe.
14. The probe according to claim 13, characterized in that the lowermost end of the gas supply line is sealed.
15. The probe according to claim 13, characterized in that the gas line is sealed by a fusible plug which melts on immersion in the metal bath.
16. The probe according to claim 13,characterized in that it is a throw-away probe and contains means for coupling it in a detachable manner to a lance.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE08800152 | 1988-02-10 | ||
| BE8800152A BE1002230A4 (en) | 1988-02-10 | 1988-02-10 | Method for measuring the gas content or metal content of a bath with fluidmetal and probe used in this method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1337246C true CA1337246C (en) | 1995-10-10 |
Family
ID=3883255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000590037A Expired - Lifetime CA1337246C (en) | 1988-02-10 | 1989-02-03 | Method for measuring a gas content or metal content of a bath of liquid metal and probe used in said method |
Country Status (4)
| Country | Link |
|---|---|
| BE (1) | BE1002230A4 (en) |
| CA (1) | CA1337246C (en) |
| ES (1) | ES2012642A6 (en) |
| ZA (1) | ZA89959B (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB821821A (en) * | 1954-08-10 | 1959-10-14 | British Aluminium Co Ltd | Improvements in the determination of the gas content of liquid metals |
| BE631059A (en) * | 1964-04-03 | 1900-01-01 | ||
| FR2252572B1 (en) * | 1973-11-27 | 1976-12-31 | Centre Rech Metallurgique | |
| US4454748A (en) * | 1982-09-28 | 1984-06-19 | Sumitomo Light Metal Industries, Ltd. | Apparatus for measuring the content of hydrogen dissolved in a molten metal |
| US4578022A (en) * | 1983-08-12 | 1986-03-25 | Kenney George B | Apparatus for in-process multi-element analysis of molten metal and other liquid materials |
-
1988
- 1988-02-10 BE BE8800152A patent/BE1002230A4/en not_active IP Right Cessation
-
1989
- 1989-02-03 CA CA000590037A patent/CA1337246C/en not_active Expired - Lifetime
- 1989-02-08 ZA ZA89959A patent/ZA89959B/en unknown
- 1989-02-10 ES ES898900485A patent/ES2012642A6/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| ES2012642A6 (en) | 1990-04-01 |
| ZA89959B (en) | 1989-10-25 |
| BE1002230A4 (en) | 1990-10-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4998432A (en) | Apparatus and method for measuring a gas content of liquid metal and probe used therein | |
| JPS5786717A (en) | Method and instrument for measuring flow rate of fluid in gaseous phase and liquid phase respectively | |
| CA1337246C (en) | Method for measuring a gas content or metal content of a bath of liquid metal and probe used in said method | |
| US4279728A (en) | Apparatus for determining ion concentration | |
| CA1330719C (en) | Device for metering a gas content of liquid metal and probe used therefor | |
| CA1337245C (en) | Method, device and probe for measuring a gas content of a bath of liquid metal | |
| CN206832610U (en) | Oil pipeline corrosion rate testing arrangement | |
| JPS5713319A (en) | Measuring instrument for liquid level | |
| US4206650A (en) | Device for introducing samples into fluid analyzer | |
| CN208953347U (en) | A kind of gas shield sulphur coating unit | |
| CN209878536U (en) | Kerosene filling device of Lee bottle for cement density detection | |
| CN108982187B (en) | Gas protection sulfur coating device and coating method thereof | |
| JPS5565117A (en) | Detection method of gas flow rate | |
| JPS58223022A (en) | Liquid level detecting method | |
| JPS56615A (en) | Flowmeter | |
| SU1049779A1 (en) | Apparatus for sampling gas | |
| JPH05171249A (en) | Porous plug | |
| Stonhill | An apparatus for thermogravimetry in hazardous atmospheres | |
| SU763585A1 (en) | Device for measuring seepage rate of soil | |
| JPS5690910A (en) | Pressure measuring lance of gas in blast furnace | |
| SU731312A1 (en) | Temperature field measuring method | |
| KR0133414Y1 (en) | Ph measuring apparatus for gathering water of a furnace | |
| JPS5746158A (en) | Temperature-measuring and/or sampling method for molten metal | |
| SU1033902A1 (en) | Liquid metal sampler | |
| RU2002577C1 (en) | Slide gate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |