EP0255915B1 - Flame photometer with constant stream regulation - Google Patents
Flame photometer with constant stream regulation Download PDFInfo
- Publication number
- EP0255915B1 EP0255915B1 EP87110967A EP87110967A EP0255915B1 EP 0255915 B1 EP0255915 B1 EP 0255915B1 EP 87110967 A EP87110967 A EP 87110967A EP 87110967 A EP87110967 A EP 87110967A EP 0255915 B1 EP0255915 B1 EP 0255915B1
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- European Patent Office
- Prior art keywords
- pressure
- throttle
- control
- burner
- gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/08—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements
- F23N5/082—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements using electronic means
Definitions
- the invention relates to a flame photometer of the type mentioned in the preamble of claim 1.
- Flame photometers with constant flow control of at least one of the fuel gas components enable the setting of a flame that burns with constant brightness over time, which permits a constant measurement evaluation of the spectral lines generated by test substances introduced into the flame. This enables accurate and reproducible measurements. It should be noted that both long-term constancy and short-term constancy must be given in order to enable evaluable measured values.
- reducing valves that control a valve with a differential pressure controlled membrane.
- the membrane is acted upon by the atmosphere on the one hand, which mostly corresponds essentially to the pressure behind the throttle, and on the other hand by the pressure in the buffer tank via the outlet line of the valve.
- the membrane regulates the actual valve of the reducing valve to a middle position with a constant flow, which results in a uniform gas flow. Disturbing flutter of such a reducing valve should be avoided if possible.
- the object of the present invention is therefore to provide a flame photometer of the type mentioned at the outset, which can be designed much more cost-effectively, precisely and reliably with regard to constant flow control. This object is achieved with the features of the characterizing part of claim 1.
- the invention provides a very simple construction which saves considerable costs compared to the reducing valves previously used for these purposes. Nevertheless, a very precise flow control is achieved, which surprisingly works without monitoring the flame parameters (temperature determination). Since the control according to the invention permits a certain pressure hysteresis, the construction can be of a greatly simplified design, and there is a switching frequency dependent on the buffer volume, which can be very low with a suitable construction. Simple and cheap switching valves can therefore be used with a long service life. Changes to the burner that change its flow resistance cannot have a disturbing effect since the throttle resistance is significantly higher than the burner resistance. Burners with fluctuating flow resistance can be used or burners with different flow resistance can be changed.
- the gas flow control shown in the figure is provided in a flame photometer, the other parts of which are omitted for the sake of simplicity.
- gas is supplied to the burner via a gas line 1 in the direction of the arrow 2 fed.
- the gas conducted via the gas line 1 can be a combustible gas mixture or one of the gas components required for combustion (fuel gas, oxidant).
- the gas flowing through is to be kept constant in the flow with the control shown, so that the burner 2 operates at a constant time.
- a switching valve 3 is interposed in the gas line 1 and, as indicated by corresponding switching symbols, has the two switching positions OPEN and CLOSE. It is operated electrically and is controlled cyclically via a control line 4.
- a buffer tank 5 is connected downstream of the switching valve 3 in the gas line 1.
- the gas pressure in the container 5 is fed via a line 6 to a pressure / voltage converter 7 which is connected via a line 8 to an input of a control device 9.
- This compares the pressure value in the container 5 with a predetermined target value and regulates the duty cycle OPEN / CLOSE of the switching valve 3 accordingly via the control line 4 such that the pressure in the container 5 is kept essentially constant.
- a throttle 10 is connected downstream of the container 5, through which the gas flows to the burner 2 via the gas line 1.
- the flow resistance of the burner 2 indicated in the figure with the corresponding symbol is with flame photometers usually very small and even.
- the gas line 1 there is generally a constant pressure essentially corresponding to the atmospheric pressure at the point between the throttle 10 and the burner 2.
- the pressure difference between the inlet and outlet at the throttle 10 is thus kept constant by the pressure control in the container 5. Therefore, the flow through the throttle 10 and thus the total gas flow is constant in the desired sense.
- a throttle 10 is used, one relative to the flow resistance of the burner 2 (including the gas line system between the throttle 10 and the burner 2) has significantly greater flow resistance.
- the total pressure drop between the container 5 and the outlet 11 of the burner into the atmosphere is then determined by the flow resistance of the throttle 10, against which the flow resistance of the burner 2 can be neglected. Changes in the resistance at the burner 2 then result in only negligibly small changes in flow.
- the control device 9 detects only the pressure in the container 5, that is to say the admission pressure of the throttle 10, via the pressure / voltage converter 7.
- the atmospheric pressure is taken into account as the pressure behind the throttle 10.
- the pressure / voltage converter 7 can in Usually be designed so that it compares the pressure on the line 6 with the atmospheric pressure and converts the differential pressure and passes it on to the controller 9.
- a second pressure / voltage converter 12 is connected via a line 13, which is connected via a line 14 in parallel to the line 8 of the converter 7 to the control device 9, which in this case works as a differential circuit and the duty cycle of the switching valve 3 readjusted such that the pressure difference between the gas pressures in lines 6 and 13, that is to say at the inlet and outlet of the throttle 10, remains constant.
- the pressure / voltage converter 7 which is always present anyway, is a differential pressure sensor, one pressure input of which is connected to the container 5 and the other of which is connected to the atmosphere, this converter 7 can also be used in a simplified embodiment to determine the differential pressure across the throttle 10 will. For this purpose, one of its pressure inputs is connected to line 6 and its other pressure input is connected to line 13. The determined differential pressure is converted into voltage and supplied to the control device 9 as an input variable. In this way, the second converter 12 can be saved when determining the differential pressure.
- the switching valve 3 can be a pressure reducer, for. B. in the form of a further throttle, upstream to reduce the high feed pressure, for example a gas bottle, to a pressure level that can be processed by the switching valve 3.
- the control device 9 is preferably designed as an electronic control device which compares the control variable arriving via line 8 or the difference between the control variables arriving via line 8 and 14 with an electrically predetermined setpoint value and, in the event of deviations, regulates the cycle ratio of the switching valve accordingly via control line 4 .
- an adjusting device for example in the form of a setting potentiometer 15, can preferably be provided, with which the electrical setpoint specification can be adjusted. In this way, the pressure in the container 5 or the differential pressure at the throttle 10 and thus the desired value of the gas flow to be kept constant can be set to the desired value, for example in order to obtain the desired flame size in the burner 2.
- the adjustment device mentioned for the control device 9 can, for example, also be designed as a preselection control, with which certain preset flows can be selected, for example, by pressing a key. It can also be a control done from a computer, e.g. B. according to a certain program. In this way it is possible to select certain flows depending on the requirements, for example depending on the measurement method currently used in the flame photometer, for example if different flame intensities are required for different photometric methods.
- the control device 9 controls the switching valve 3 as a function of the differential pressure at the throttle 10
- the construction according to the invention which is very simple to implement in terms of circuit technology and which has proven itself in tests, consists in switching on the switching valve 3 when the pressure falls below a first, and switching on when a predetermined higher pressure is exceeded. This results in a pressure fluctuating in the container 5 between the two predetermined pressure values, although this hysteresis can be kept very small. If the volume of the container is large enough, the switching valve 3 works very slowly. The control and the switching valve can therefore be constructed very simply.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Feeding And Controlling Fuel (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
Abstract
Description
Die Erfindung betrifft ein Flammenphotometer der im Oberbegriff des Anspruches 1 genannten Art.The invention relates to a flame photometer of the type mentioned in the preamble of
Flammenphotometer mit Konstantflußregelung wenigstens einer der Brenngaskomponenten ermöglichen die Einstellung einer mit zeitlich konstanter Helligkeit brennenden Flamme, die eine zeitlich konstante Meßauswertung der von in die Flamme eingebrachten Testsubstanzen erzeugten Spektrallinien gestattet. Auf diese Weise werden genaue und reproduzierbare Messungen ermöglicht. Dabei ist zu beachten, daß sowohl Langzeitkonstanz als auch Kurzzeitkonstanz gegeben sein muß, um auswertbare Meßwerte zu ermöglichen.Flame photometers with constant flow control of at least one of the fuel gas components enable the setting of a flame that burns with constant brightness over time, which permits a constant measurement evaluation of the spectral lines generated by test substances introduced into the flame. This enables accurate and reproducible measurements. It should be noted that both long-term constancy and short-term constancy must be given in order to enable evaluable measured values.
Derartige Flammenphotometer der eingangs genannten Art sind seit längerem bekannt, beispielsweise aus der Literaturstelle
R. Herrmann - C.Th.J. Alkemade: Flammenphotometrie.Such flame photometers of the type mentioned have been known for a long time, for example from the reference
R. Herrmann - C.Th.J. Alkemade: flame photometry.
Hieraus ist es bekannt, als Steuerventil der eingangs genannten Art, Reduzierventile zu verwenden, die mit einer differenzdruckgesteuerten Membran ein Ventil steuern. Die Membran wird einerseits von der Atmosphäre beaufschlagt, die zumeist im wesentlichen dem Druck hinter der Drossel entspricht und andererseits über die Ausgangsleitung des Ventiles vom Druck im Pufferbehälter. Bei gleichmäßig arbeitendem Brenner, also im wesentlichen gleichmäßigem Gasfluß, regelt die Membran das eigentliche Ventil des Reduzierventiles auf eine mittlere Stellung mit konstantem Fluß ein, woraus sich ein gleichmäßiger Gasfluß ergibt. Störendes Flattern eines solchen Reduzierventiles soll nach Möglichkeit vermieden werden.From this it is known to use as a control valve of the type mentioned, reducing valves that control a valve with a differential pressure controlled membrane. The membrane is acted upon by the atmosphere on the one hand, which mostly corresponds essentially to the pressure behind the throttle, and on the other hand by the pressure in the buffer tank via the outlet line of the valve. When the burner is working uniformly, that is to say essentially a uniform gas flow, the membrane regulates the actual valve of the reducing valve to a middle position with a constant flow, which results in a uniform gas flow. Disturbing flutter of such a reducing valve should be avoided if possible.
Auch in jüngerer Zeit werden für die eingangs genannten Zwecke noch derartige Reduzierventile verwendet, wie die DE-OS 34 07 552 zeigt. Das membrangesteuerte Reduzierventil ist bei dieser Konstruktion dahingehend verbessert, daß es mit einer motorisch arbeitenden Einstelleinrichtung ausgerüstet ist.Even recently, such reducing valves have been used for the purposes mentioned at the outset, as DE-OS 34 07 552 shows. The diaphragm-controlled reducing valve is improved in this construction in that it is equipped with a motor-operated adjustment device.
Die bekannten Reduzierventile arbeiten in der Regel befriedigend, lassen sich aber nicht mit heutzutage erforderlicher sehr hoher Präzision regeln und weisen den Nachteil einer komplizierten Konstruktion mit entsprechender Anfälligkeit und hohen Kosten sowie den Nachteil aufwendiger Ansteuertechnik auf.The known reducing valves generally work satisfactorily, but cannot be regulated with the very high precision required today and have the disadvantage of a complicated construction with corresponding vulnerability and high costs as well as the disadvantage of complex control technology.
Ferner ist aus der EP-A-0068589 für derartige Zwecke eine Regelung bekannt, bei der als Steuerventil ein Schaltventil verwendet wird. Dieses wird allerdings gesteuert in Abhängigkeit von der Brennertemperatur, was einen aufwendigen und störempfindlichen Temperatursensor erforderlich macht.Furthermore, a control is known from EP-A-0068589 for such purposes, in which a switching valve is used as the control valve. However, this is controlled as a function of the burner temperature, which requires a complex and fault-sensitive temperature sensor.
Die Aufgabe der vorliegenden Erfindung besteht daher darin, ein Flammenphotometer der eingangs genannten Art zu schaffen, das hinsichtlich der Konstantflußregelung wesentlich kostengünstiger, präziser und zuverlässiger ausbildbar ist. Diese Aufgabe wird erfindungsgemäß mit den Merkmalen des Kennzeichnungsteiles des Anspruches 1 gelöst.The object of the present invention is therefore to provide a flame photometer of the type mentioned at the outset, which can be designed much more cost-effectively, precisely and reliably with regard to constant flow control. This object is achieved with the features of the characterizing part of
Mit der Erfindung wird eine sehr einfache Konstruktion vorgelegt, die gegenüber den bisher für diese Zwecke verwendeten Reduzierventilen erhebliche Kosten einspart. Dennoch wird eine sehr präzise Flußsteuerung erreicht, die überraschenderweise auch ohne Überwachung der Flammenparameter (Temperaturermittlung) auskommt. Da die erfindungsgemäße Steuerung eine gewisse Druckhysterese zuläßt, kann die Konstruktion stark vereinfacht ausgebildet sein, und es ergibt sich eine vom Puffervolumen abhängige Schaltfrequenz, die bei geeigneter Konstruktionsweise sehr niedrig sein kann. Einfache und billige Schaltventile können daher mit hoher Lebensdauer verwendet werden. Veränderungen am Brenner, die dessen Durchflußwiderstand ändern, können sich nicht störend bemerkbar machen, da der Drosselwiderstand wesentlich höher ist als der Brennerwiderstand. Es können Brenner mit schwankendem Strömungswiderstand verwendet oder Brenner unterschiedlichen Strömungswiderstandes gewechselt werden.The invention provides a very simple construction which saves considerable costs compared to the reducing valves previously used for these purposes. Nevertheless, a very precise flow control is achieved, which surprisingly works without monitoring the flame parameters (temperature determination). Since the control according to the invention permits a certain pressure hysteresis, the construction can be of a greatly simplified design, and there is a switching frequency dependent on the buffer volume, which can be very low with a suitable construction. Simple and cheap switching valves can therefore be used with a long service life. Changes to the burner that change its flow resistance cannot have a disturbing effect since the throttle resistance is significantly higher than the burner resistance. Burners with fluctuating flow resistance can be used or burners with different flow resistance can be changed.
Weiterhin vorteilhaft sind die Merkmale des Anspruches 2 vorgesehen. Hierdurch wird der Regelungs- und Installationsaufwand verringert. Wenn der Strömungswiderstand der der Drossel nachgeschalteten Gasstrecke, die im wesentlichen nur aus dem Brenner besteht, ausreichend konstant ist, was in der Regel der Fall ist, so ergibt sich auch mit einer solchen einfachen Konstruktion eine ausreichend genaue Regelung.The features of
Schließlich sind vorteilhaft die Merkmale des Anspruches 3 vorgesehen. Auf diese Weise kann sehr einfach durch Verstellung an der Regeleinrichtung der gewünschte Sollfluß eingestellt werden.Finally, the features of
In der Zeichnung ist die Erfindung beispielsweise und schematisch dargestellt.In the drawing, the invention is shown for example and schematically.
Die in der Figur dargestellte Gasflußregelung ist in einem Flammenphotometer vorgesehen, dessen sonstige Teile der Einfachheit halber weggelassen sind.The gas flow control shown in the figure is provided in a flame photometer, the other parts of which are omitted for the sake of simplicity.
Von einer ebenfalls nicht dargestellten Gasversorgung, beispielsweise einer Gasflasche, wird über eine Gasleitung 1 in Pfeilrichtung Gas dem Brenner 2 zugeführt.From a gas supply, also not shown, for example a gas bottle, gas is supplied to the burner via a
Bei dem über die Gasleitung 1 geführten Gas kann es sich um eine brennfähige Gasmischung oder um eine der zur Verbrennung benötigten Gaskomponenten (Brenngas, Oxydans) handeln. Das durchströmende Gas ist mit der dargestellten Regelung im Fluß konstant zu halten, damit der Brenner 2 zeitkonstant arbeitet.The gas conducted via the
In der Gasleitung 1 ist ein Schaltventil 3 zwischengeschaltet, das, wie mit entsprechenden Schaltsymbolen angedeutet, die beiden Schaltstellungen AUF und ZU aufweist. Es wird elektrisch betrieben und über eine Steuerleitung 4 taktweise angesteuert.A
Dem Schaltventil 3 ist in der Gasleitung 1 ein Pufferbehälter 5 nachgeschaltet. Über eine Leitung 6 wird der Gasdruck im Behälter 5 einem Druck-/Spannungswandler 7 zugeführt, der über eine Leitung 8 an einen Eingang einer Steuereinrichtung 9 angeschlossen ist. Diese vergleicht den Druckwert im Behälter 5 mit einem vorgegebenen Sollwert und regelt entsprechend über die Steuerleitung 4 das Taktverhältnis AUF/ZU des Schaltventiles 3 derart nach, daß der Druck im Behälter 5 im wesentlichen konstant gehalten wird.A
Dem Behälter 5 ist eine Drossel 10 nachgeschaltet, durch die das Gas über die Gasleitung 1 dem Brenner 2 zufließt.A
Der in der Figur mit dem entsprechenden Symbol angedeutete Strömungswiderstand des Brenners 2 ist bei Flammenphotometern in der Regel sehr klein und gleichmäßig. In der Gasleitung 1 herrscht an der Stelle zwischen der Drossel 10 und dem Brenner 2 daher in der Regel konstanter, im wesentlichen dem Atmosphärendruck entsprechender Druck. Die Druckdifferenz zwischen Eingang und Ausgang an der Drossel 10 wird somit durch die Druckregelung im Behälter 5 konstant gehalten. Daher ist der Durchfluß durch die Drossel 10 und somit der Gesamtgasfluß im gewünschten Sinne konstant.The flow resistance of the
Da unter Umständen Schwankungen des Strömungswiderstandes im Brenner 2 zu befürchten sind und von der Konstruktion her zugelassen werden soll, daß der Brenner 2 gegen einen anderen Brenner anderen Strömungswiderstandes gewechselt werden kann, wird so ist eine Drossel 10 verwendet, die einen gegenüber dem Strömungswiderstand des Brenners 2 (einschließlich des Gasleitungssystems zwischen der Drossel 10 und dem Brenner 2) erheblich größeren Strömungwiderstand aufweist. Der gesamte Druckabfall zwischen dem Behälter 5 und dem Ausgang 11 des Brenners in die Atmosphäre wird dann durch den Strömungswiderstand der Drossel 10 bestimmt, gegen den der Strömungswiderstand des Brenners 2 vernachlässigt werden kann. Änderungen des Widerstandes am Brenner 2 ergeben dann nur vernachlässigbar kleine Durchflußänderungen.Since fluctuations in the flow resistance in the
In der beschriebenen Ausführungsform erfaßt die Regeleinrichtung 9 über den Druck-/Spannungwandler 7 nur den Druck im Behälter 5, also den Vordruck der Drossel 10. Als Druck hinter der Drossel 10 wird bei dieser Ausführungsform der Atmosphärendruck berücksichtigt. Der Druck-/Spannungswandler 7 kann in üblicher Weise so ausgelegt sein, daß er den Druck auf der Leitung 6 mit dem Atmosphärendruck vergleicht und den Differenzdruck wandelt und an den Regler 9 weitergibt.In the described embodiment, the control device 9 detects only the pressure in the
Zur exakten Erfassung der Druckdifferenz an der Drossel 10 kann eine alternative Konstruktion wie folgt vorgesehen sein.An alternative construction can be provided as follows for exact detection of the pressure difference at the
Am Ausgang der Drossel 10 ist ein zweiter Druck-/Spannungswandler 12 über eine Leitung 13 angeschlossen, der über eine Leitung 14 parallel zur Leitung 8 des Wandlers 7 an die Steuereinrichtung 9 angeschlossen ist, die in diesem Falle als Differenzschaltung arbeitet und das Taktverhältnis des Schaltventiles 3 derart nachregelt, daß die Druckdifferenz zwischen den Gasdrucken in den Leitungen 6 und 13, also am Eingang und Ausgang der Drossel 10, konstant bleibt.At the output of the
Bei dieser Differenzdruckregelung kann der Strömungswiderstand im Brenner 2 und dessen Leitungssystem beliebige Werte annehmen, ohne die Konstanthaltung des Gasflusses zu stören.With this differential pressure control, the flow resistance in the
Da in der Regel der ohnehin stets vorhandene Druck/Spannungswandler 7 ein Differenzdruckaufnehmer ist, dessen einer Druckeingang an den Behälter 5 und dessen anderer Druckeingang an die Atmosphäre angeschlossen ist, kann dieser Wandler 7 in vereinfachter Ausführungsform auch zur Bestimmung des Differenzdruckes über der Drossel 10 verwendet werden. Dazu wird sein einer Druckeingang an die Leitung 6 und sein anderer Druckeingang an die Leitung 13 angeschlossen. Der ermittelte Differenzdruck wird in Spannung gewandelt und der Steuereinrichtung 9 als Eingangsgröße zugeführt. Auf diese Weise kann bei Ermittlung des Differenzdruckes der zweite Wandler 12 eingespart werden.Since the pressure / voltage converter 7, which is always present anyway, is a differential pressure sensor, one pressure input of which is connected to the
Dem Schaltventil 3 kann in üblicher Weise ein Druckminderer, z. B. in Form einer weiteren Drossel, vorgeschaltet sein, um den hohen Speisedruck, beispielsweise einer Gasflasche, auf ein vom Schaltventil 3 verarbeitbares Druckniveau zu reduzieren.The
Die Steuereinrichtung 9 ist vorzugsweise als elektronische Steuereinrichtung ausgebildet, die die über die Leitung 8 ankommende Steuergröße bzw. die Differenz der über die Leitung 8 und 14 ankommenden Steuergrößen mit einem elektrisch vorgegebenen Sollwert vergleicht und bei Abweichungen über die Steuerleitung 4 das Taktverhältnis des Schaltventiles entsprechend nachregelt. Dabei kann vorzugsweise eine Verstelleinrichtung, beispielsweise in Form eines Stellpotentiometers 15 vorgesehen sein, mit der die elektrische Sollwertvorgabe verstellt werden kann. Auf diese Weise kann der Druck im Behälter 5 bzw. der Differenzdruck an der Drossel 10 und damit der Sollwert des konstant zu haltenden Gasflusses auf den gewünschten Wert eingestellt werden, um beispielsweise im Brenner 2 die gewünschte Flammengröße zu erhalten.The control device 9 is preferably designed as an electronic control device which compares the control variable arriving via
Die erwähnte Verstelleinrichtung für die Steuereinrichtung 9 kann beispielsweise auch als Vorwahlsteuerung ausgebildet sein, mit der beispielsweise über Tastendruck bestimmte voreingestellte Flüsse wählbar sind. Es kann auch eine Ansteuerung aus einem Computer erfolgen, z. B. nach einem bestimmten Programm. Auf diese Weise ist es möglich, je nach Anforderung bestimmte Flüsse zu wählen, beispielsweise je nach dem im Flammenphotometer zur Zeit verwendeten Meßverfahren, wenn also beispielsweise für unterschiedliche fotometrische Verfahren unterschiedliche Flammenintensitäten erforderlich sind.The adjustment device mentioned for the control device 9 can, for example, also be designed as a preselection control, with which certain preset flows can be selected, for example, by pressing a key. It can also be a control done from a computer, e.g. B. according to a certain program. In this way it is possible to select certain flows depending on the requirements, for example depending on the measurement method currently used in the flame photometer, for example if different flame intensities are required for different photometric methods.
Die Regeleinrichtung 9 steuert das Schaltventil 3 in Abhängigkeit vom Differenzdruck an der Drossel 10The control device 9 controls the
Die erfindungsgemäße, schaltungstechnisch sehr einfach realisierbare Konstruktion, die sich in Versuchen bewährt hat, besteht darin, das Schaltventil 3 bei Unterschreiten eines ersten tieferliegenden Druckes aufzuschalten und bei Überschreiten eines vorgegebenen höheren Druckes zuzuschalten. Hierbei ergibt sich also im Behälter 5 ein zwischen den beiden vorgegebenen Druckwerten schwankender Druck, wobei diese Hysterese aber sehr klein gehalten werden kann. Wenn der Behälter in seinem Volumen entsprechend groß ist, arbeitet das Schaltventil 3 sehr langsam. Die Regelung und das Schaltventil können folglich sehr einfach konstruiert werden.The construction according to the invention, which is very simple to implement in terms of circuit technology and which has proven itself in tests, consists in switching on the switching
Claims (3)
- Flame photometer with constant flow control of at least one of the combustion gas components by means of a control valve (3) which directs the gas flow into a buffer container (5), connected downstream of which via a throttle (10) is the burner, the control valve controlling the pressure in the buffer container in dependence on the pressure differential across the throttle in such a manner that the pressure differential remains constant, characterised in that the control valve is constructed as an open-close pilot valve (3) which is switched open by a control device (9) when the pressure differential falls below a predetermined value and is switched closed when a predetermined second higher pressure differential is exceeded, the flow resistance of the throttle (10) being so much greater than that of the gas path (2) downstream of it that when the residual resistance alters resulting gas flow inaccuracies remain below a predetermined permissible inaccuracy threshold.
- Flame photometer as claimed in the preceding claim, characterised in that the control device (9) controls in dependence on the inlet pressure (6) of the throttle (10), atmospheric pressure being considered to be the outlet pressure of the throttle (10).
- Flame photometer as claimed in one of the preceding claims, characterised in that the control device (9) has an adjustment device for adjusting the desired pressure differential.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT87110967T ATE62746T1 (en) | 1986-08-06 | 1987-07-29 | FLAME PHOTOMETER WITH CONSTANT FLOW CONTROL. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3626644 | 1986-08-06 | ||
| DE3626644 | 1986-08-06 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0255915A2 EP0255915A2 (en) | 1988-02-17 |
| EP0255915A3 EP0255915A3 (en) | 1988-10-05 |
| EP0255915B1 true EP0255915B1 (en) | 1991-04-17 |
Family
ID=6306810
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP87110967A Expired - Lifetime EP0255915B1 (en) | 1986-08-06 | 1987-07-29 | Flame photometer with constant stream regulation |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0255915B1 (en) |
| AT (1) | ATE62746T1 (en) |
| DE (1) | DE3769395D1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03282252A (en) * | 1990-03-30 | 1991-12-12 | Hitachi Ltd | Apparatus for analyzing very minute amount of element of plasma |
| DE19641920A1 (en) * | 1996-10-11 | 1998-04-16 | Gaggenau Werke | Method and device for controlling the flame size of gas-operated cooking or baking devices |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2245104A1 (en) * | 1972-09-14 | 1974-04-04 | Vaillant Joh Kg | LIQUID HEATERS |
| US4250553A (en) * | 1979-03-05 | 1981-02-10 | The Perkin-Elmer Corporation | Fluid flow measurement system |
| NL8103022A (en) * | 1981-06-23 | 1983-01-17 | Conma Nv | PRESSURE CONTROL METHOD. |
| DE3407552A1 (en) * | 1984-03-01 | 1985-09-05 | Bodenseewerk Perkin Elmer Co | GAS CONTROL DEVICE FOR CONTROLLING THE FUEL GAS AND OXIDE SUPPLY TO A BURNER IN AN ATOMIC ABSORPTION SPECTROMETER |
-
1987
- 1987-07-29 DE DE8787110967T patent/DE3769395D1/en not_active Expired - Lifetime
- 1987-07-29 EP EP87110967A patent/EP0255915B1/en not_active Expired - Lifetime
- 1987-07-29 AT AT87110967T patent/ATE62746T1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0255915A3 (en) | 1988-10-05 |
| DE3769395D1 (en) | 1991-05-23 |
| EP0255915A2 (en) | 1988-02-17 |
| ATE62746T1 (en) | 1991-05-15 |
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