EP0617234A1 - Détecteur de flamme à ionisation - Google Patents

Détecteur de flamme à ionisation Download PDF

Info

Publication number
EP0617234A1
EP0617234A1 EP94102367A EP94102367A EP0617234A1 EP 0617234 A1 EP0617234 A1 EP 0617234A1 EP 94102367 A EP94102367 A EP 94102367A EP 94102367 A EP94102367 A EP 94102367A EP 0617234 A1 EP0617234 A1 EP 0617234A1
Authority
EP
European Patent Office
Prior art keywords
circuit
test
flame
ionization
capacitance
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.)
Withdrawn
Application number
EP94102367A
Other languages
German (de)
English (en)
Inventor
Alfred Sinner
Rudolf Dipl.-Ing. Haug (Fh)
Ralf Dipl.-Ing. Sanders (Fh)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Karl Dungs GmbH and Co KG
Original Assignee
Karl Dungs GmbH and Co KG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Karl Dungs GmbH and Co KG filed Critical Karl Dungs GmbH and Co KG
Publication of EP0617234A1 publication Critical patent/EP0617234A1/fr
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • 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
    • F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
    • F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2223/00—Signal processing; Details thereof
    • F23N2223/08—Microprocessor; Microcomputer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2227/00—Ignition or checking
    • F23N2227/12—Burner simulation or checking
    • F23N2227/16—Checking components, e.g. electronic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/24—Preventing development of abnormal or undesired conditions, i.e. safety arrangements

Definitions

  • the invention relates to an ionization flame monitor, in particular for automatic burner controls.
  • Such an ionization flame monitor should not only be able to reliably detect the presence or absence of a flame in an automatic burner control unit, but should also offer the possibility of using a z. B. from a higher-level automatic control test signal to be checked for its functionality and also allow a statement about the flowing ionization current.
  • An essential feature of the invention is that a capacitance is provided which is connected to the secondary circuit of an ignition transformer and is charged to a certain voltage value when no ionization current flows and is discharged when an ionization current flows so that its rate of discharge is a measure of the level of the ionization current
  • An input of a monitoring circuit is connected to the capacitance in order to produce an output signal, which indicates the presence of a flame, when the voltage across the capacitance falls below a predetermined voltage value.
  • the capacitance is preferably connected to the secondary circuit of the ignition transformer by means of a coupling circuit which, in the simplest case, contains at least one resistance element.
  • the coupling circuit can be activated or deactivated by an externally supplied signal.
  • the monitoring circuit is preferably designed as a threshold switch with hysteresis.
  • a test circuit is provided which is connected to the discharge circuit of the capacitance in order to simulate the absence of the flame during operation when the monitoring circuit has an output signal. This makes it when testing the ionization flame monitor under no circumstances possible to simulate a flame.
  • the test circuit preferably has a transistor circuit to which a test signal is applied in order to apply a voltage to the input of the monitoring circuit as a function of the test signal, which voltage simulates the absence of the flame.
  • an optocoupler is provided in the transistor circuit in order to galvanically isolate the test signal from the other ionization flame monitor circuit.
  • the speed of the discharge indicates the size of the ionization current via the time constant of the capacitance.
  • an evaluation circuit which is supplied with the output signal of the monitoring circuit is preferably provided and measures the time period immediately after the termination of the test signal until the voltage across the capacitance has fallen below the predetermined voltage value.
  • the evaluation circuit has a microprocessor which can also generate the test signal at the same time.
  • the evaluation circuit can generate the test signal in predetermined periodic periods or alternatively depending on the operating conditions of the automatic burner control unit.
  • the proposed circuit can easily be miniaturized in such a way that it can be accommodated in a plug of a cable which forms an electrical connection of the ignition electrode.
  • a coupling circuit K a capacitance C3.
  • the capacitor C3 is charged to the operating voltage U B via the resistor R3.
  • an ionization current I F flows due to the flame development, the capacitor C3 is discharged.
  • an input S e of a monitoring circuit S connected, which detects when the capacitor C3 is discharged, that is, when the voltage U C3 across the capacitor C3 has dropped below a predetermined voltage value.
  • the output of the monitoring circuit S then emits a corresponding output signal S a , which can be evaluated by an evaluation circuit A.
  • a test circuit T is connected to the circuit point E via a dashed line, which pulls the input S e of the monitoring circuit S to the operating voltage U B in response to a test signal “Test”.
  • the ionization flame monitor is only tested during operation, ie if there is a flame. Because of this and the described discharge of the capacitance C3 by the ionization current, it cannot happen that a flame is simulated during the test process, which is very important from a safety point of view.
  • a preferred overall circuit of the ionization flame monitor, alternative circuit variants of the test circuit T and an interface circuit between the output S a of the monitoring circuit S and an evaluation circuit A and their function are described in more detail below with reference to FIGS. 2 to 6.
  • the circuit shown in FIG. 2 has a voltage generator circuit which generates the operating voltage U B.
  • a surge arrester F 1 is coupled in FIG. 2 to the line carrying the ionization current I F , which is led at its other end to a protective conductor terminal P E.
  • the coupling circuit K has a resistance element R2, which also functions as a safety resistor in the event of a short circuit in the ionization input.
  • the monitoring circuit consists of the series circuit of R3 with C3 and a threshold switch V5 connected to the circuit point E with hysteresis. If the voltage at switching point E rises above 2/3 U B , the output signal of the integrated threshold switch V5 switches to the "0" state. As long as there is no flame, the capacitor C3 is therefore charged to the operating voltage U B , and the output of the threshold switch V5 is "0".
  • the function-time diagram in FIG. 6 shows the time behavior of the ionization current, the capacitor voltage U C3 in the presence and absence of the ionization current I F and in the case of the test signal with the flame present, and the time behavior of the output signal S a at the output of the monitoring circuit S.
  • the test circuit T pulls the input signal S e of the monitoring circuit S when the test signal "Test" is applied to the operating voltage U B.
  • the output signal S a of the monitoring circuit S ie the threshold switch V5
  • the evaluation circuit A which can be coupled to the output S a of the monitoring circuit S, makes it possible to measure the length of time dt that the capacitor C3 needs to discharge to 1/3 U B when the flame is present.
  • This time period dt or discharge rate is a measure of the strength of the flowing ionization current.
  • the ionization current is inversely proportional to the time period dt.
  • the time period dt is also dependent on the capacitance of the capacitor C3, the resistance R2 and the flame resistance.
  • the first variant T 1 shown in FIG. 3 of the test circuit contains a transistor circuit consisting of two transistors V7 and V8, which applies the operating voltage U B to the circuit point E when the "Test" signal is applied.
  • the second variant T2 of the test circuit contains an optocoupler V9 according to FIG. 4, which causes a galvanic isolation of the test signal "Test” from the rest of the circuit of the ionization flame monitor.
  • FIG. 5 shows an optocoupler V10, which enables a galvanic decoupling of the evaluation circuit A from the output of the monitoring circuit S.
  • the evaluation circuit A itself is not shown, but it has become clear that this circuit should preferably have an evaluation circuit for the period dt.
  • the evaluation circuit A particularly preferably has a microprocessor which can also generate the test signal "Test".
  • the 1 shows the possibility of activating or deactivating the coupling circuit K by means of a coupling activation signal K E.
  • the signal K E can also be generated by the microprocessor of the evaluation circuit.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
EP94102367A 1993-03-24 1994-02-17 Détecteur de flamme à ionisation Withdrawn EP0617234A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4309454A DE4309454C2 (de) 1993-03-24 1993-03-24 Ionisationsflammenwächter
DE4309454 1993-03-24

Publications (1)

Publication Number Publication Date
EP0617234A1 true EP0617234A1 (fr) 1994-09-28

Family

ID=6483648

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94102367A Withdrawn EP0617234A1 (fr) 1993-03-24 1994-02-17 Détecteur de flamme à ionisation

Country Status (2)

Country Link
EP (1) EP0617234A1 (fr)
DE (1) DE4309454C2 (fr)

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0908679A1 (fr) * 1997-10-10 1999-04-14 Electrowatt Technology Innovation AG Circuit de surveillance de flammes
EP1719947A1 (fr) 2005-05-06 2006-11-08 Siemens Building Technologies HVAC Products GmbH Procédé et dispositif de contrôle de flammes
DE102009057121A1 (de) 2009-12-08 2011-06-09 Scheer Heizsysteme & Produktionstechnik Gmbh Verfahren zur qualitativen Überwachung und Regelung des Verbrennungszustandes eines Heizkesselsystems mittels eines Ionisationsflammenwächters
EP1983264A3 (fr) * 2007-04-16 2014-02-19 Viessmann Werke GmbH & Co. KG Dispositif de surveillance de flammes doté d'un système de mesure et de production de tension
US8839815B2 (en) 2011-12-15 2014-09-23 Honeywell International Inc. Gas valve with electronic cycle counter
US8899264B2 (en) 2011-12-15 2014-12-02 Honeywell International Inc. Gas valve with electronic proof of closure system
US8905063B2 (en) 2011-12-15 2014-12-09 Honeywell International Inc. Gas valve with fuel rate monitor
US8947242B2 (en) 2011-12-15 2015-02-03 Honeywell International Inc. Gas valve with valve leakage test
US9074770B2 (en) 2011-12-15 2015-07-07 Honeywell International Inc. Gas valve with electronic valve proving system
US9234661B2 (en) 2012-09-15 2016-01-12 Honeywell International Inc. Burner control system
US9557059B2 (en) 2011-12-15 2017-01-31 Honeywell International Inc Gas valve with communication link
US9645584B2 (en) 2014-09-17 2017-05-09 Honeywell International Inc. Gas valve with electronic health monitoring
US9683674B2 (en) 2013-10-29 2017-06-20 Honeywell Technologies Sarl Regulating device
US9835265B2 (en) 2011-12-15 2017-12-05 Honeywell International Inc. Valve with actuator diagnostics
US9841122B2 (en) 2014-09-09 2017-12-12 Honeywell International Inc. Gas valve with electronic valve proving system
US9846440B2 (en) 2011-12-15 2017-12-19 Honeywell International Inc. Valve controller configured to estimate fuel comsumption
US9851103B2 (en) 2011-12-15 2017-12-26 Honeywell International Inc. Gas valve with overpressure diagnostics
US9995486B2 (en) 2011-12-15 2018-06-12 Honeywell International Inc. Gas valve with high/low gas pressure detection
US10024439B2 (en) 2013-12-16 2018-07-17 Honeywell International Inc. Valve over-travel mechanism
US10422531B2 (en) 2012-09-15 2019-09-24 Honeywell International Inc. System and approach for controlling a combustion chamber
US10503181B2 (en) 2016-01-13 2019-12-10 Honeywell International Inc. Pressure regulator
US10564062B2 (en) 2016-10-19 2020-02-18 Honeywell International Inc. Human-machine interface for gas valve
US10697815B2 (en) 2018-06-09 2020-06-30 Honeywell International Inc. System and methods for mitigating condensation in a sensor module
US11073281B2 (en) 2017-12-29 2021-07-27 Honeywell International Inc. Closed-loop programming and control of a combustion appliance
WO2023012019A1 (fr) * 2021-08-05 2023-02-09 Truma Gerätetechnik GmbH & Co. KG Brûleur à élément de commande et à électrode d'allumage et d'ionisation et procédé de surveillance et d'allumage de la flamme d'un brûleur

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19631821C2 (de) * 1996-08-07 1999-08-12 Stiebel Eltron Gmbh & Co Kg Verfahren und Einrichtung zur Sicherheits-Flammenüberwachung bei einem Gasbrenner
EP0806610B1 (fr) * 1996-05-09 2001-07-04 STIEBEL ELTRON GmbH & Co. KG Procédé pour le fonctionnement d'un brûleur à gaz
DE10027846A1 (de) * 2000-05-25 2001-11-29 Siemens Building Tech Ag Signalgeber
DE10247168B4 (de) * 2002-10-10 2004-09-09 Karl Dungs Gmbh & Co. Kg Flammenwächter mit Selbsttestfunktion und Verfahren zur Betriebsüberwachung

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR989589A (fr) * 1949-06-27 1951-09-11 Gaz De France Perfectionnements aux dispositifs électroniques de sécurité ou de commande contrôlés notamment par l'intervention d'une flamme
US3877864A (en) * 1974-07-29 1975-04-15 Itt Spark igniter system for gas appliance pilot ignition
US4000961A (en) * 1975-08-26 1977-01-04 Eclipse, Inc. Primary flame safeguard system
JPS62142922A (ja) * 1985-12-17 1987-06-26 Matsushita Electric Ind Co Ltd 燃焼検出回路
JPS62255729A (ja) * 1986-04-30 1987-11-07 Matsushita Electric Ind Co Ltd 燃焼状態検知回路

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4168949A (en) * 1977-09-26 1979-09-25 Honeywell Inc. Flame signal stabilization circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR989589A (fr) * 1949-06-27 1951-09-11 Gaz De France Perfectionnements aux dispositifs électroniques de sécurité ou de commande contrôlés notamment par l'intervention d'une flamme
US3877864A (en) * 1974-07-29 1975-04-15 Itt Spark igniter system for gas appliance pilot ignition
US4000961A (en) * 1975-08-26 1977-01-04 Eclipse, Inc. Primary flame safeguard system
JPS62142922A (ja) * 1985-12-17 1987-06-26 Matsushita Electric Ind Co Ltd 燃焼検出回路
JPS62255729A (ja) * 1986-04-30 1987-11-07 Matsushita Electric Ind Co Ltd 燃焼状態検知回路

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 11, no. 368 (M - 647) 2 December 1987 (1987-12-02) *
PATENT ABSTRACTS OF JAPAN vol. 12, no. 134 (M - 689) 23 April 1988 (1988-04-23) *

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0908679A1 (fr) * 1997-10-10 1999-04-14 Electrowatt Technology Innovation AG Circuit de surveillance de flammes
WO1999019672A1 (fr) * 1997-10-10 1999-04-22 Siemens Building Technologies Ag Procede et dispositif pour la surveillance d'une flamme
US6501383B1 (en) 1997-10-10 2002-12-31 Siemens Building Technologies Ag Method and device for monitoring a flame
EP1719947A1 (fr) 2005-05-06 2006-11-08 Siemens Building Technologies HVAC Products GmbH Procédé et dispositif de contrôle de flammes
US7382140B2 (en) 2005-05-06 2008-06-03 Siemens Building Technologies Hvac Products Gmbh Method and device for flame monitoring
EP1983264A3 (fr) * 2007-04-16 2014-02-19 Viessmann Werke GmbH & Co. KG Dispositif de surveillance de flammes doté d'un système de mesure et de production de tension
DE102009057121A1 (de) 2009-12-08 2011-06-09 Scheer Heizsysteme & Produktionstechnik Gmbh Verfahren zur qualitativen Überwachung und Regelung des Verbrennungszustandes eines Heizkesselsystems mittels eines Ionisationsflammenwächters
US8947242B2 (en) 2011-12-15 2015-02-03 Honeywell International Inc. Gas valve with valve leakage test
US9835265B2 (en) 2011-12-15 2017-12-05 Honeywell International Inc. Valve with actuator diagnostics
US8905063B2 (en) 2011-12-15 2014-12-09 Honeywell International Inc. Gas valve with fuel rate monitor
US10697632B2 (en) 2011-12-15 2020-06-30 Honeywell International Inc. Gas valve with communication link
US9074770B2 (en) 2011-12-15 2015-07-07 Honeywell International Inc. Gas valve with electronic valve proving system
US9995486B2 (en) 2011-12-15 2018-06-12 Honeywell International Inc. Gas valve with high/low gas pressure detection
US9557059B2 (en) 2011-12-15 2017-01-31 Honeywell International Inc Gas valve with communication link
US9851103B2 (en) 2011-12-15 2017-12-26 Honeywell International Inc. Gas valve with overpressure diagnostics
US9846440B2 (en) 2011-12-15 2017-12-19 Honeywell International Inc. Valve controller configured to estimate fuel comsumption
US8839815B2 (en) 2011-12-15 2014-09-23 Honeywell International Inc. Gas valve with electronic cycle counter
US8899264B2 (en) 2011-12-15 2014-12-02 Honeywell International Inc. Gas valve with electronic proof of closure system
US10851993B2 (en) 2011-12-15 2020-12-01 Honeywell International Inc. Gas valve with overpressure diagnostics
US9657946B2 (en) 2012-09-15 2017-05-23 Honeywell International Inc. Burner control system
US11421875B2 (en) 2012-09-15 2022-08-23 Honeywell International Inc. Burner control system
US9234661B2 (en) 2012-09-15 2016-01-12 Honeywell International Inc. Burner control system
US10422531B2 (en) 2012-09-15 2019-09-24 Honeywell International Inc. System and approach for controlling a combustion chamber
US9683674B2 (en) 2013-10-29 2017-06-20 Honeywell Technologies Sarl Regulating device
US10215291B2 (en) 2013-10-29 2019-02-26 Honeywell International Inc. Regulating device
US10024439B2 (en) 2013-12-16 2018-07-17 Honeywell International Inc. Valve over-travel mechanism
US9841122B2 (en) 2014-09-09 2017-12-12 Honeywell International Inc. Gas valve with electronic valve proving system
US10203049B2 (en) 2014-09-17 2019-02-12 Honeywell International Inc. Gas valve with electronic health monitoring
US9645584B2 (en) 2014-09-17 2017-05-09 Honeywell International Inc. Gas valve with electronic health monitoring
US10503181B2 (en) 2016-01-13 2019-12-10 Honeywell International Inc. Pressure regulator
US10564062B2 (en) 2016-10-19 2020-02-18 Honeywell International Inc. Human-machine interface for gas valve
US11073281B2 (en) 2017-12-29 2021-07-27 Honeywell International Inc. Closed-loop programming and control of a combustion appliance
US10697815B2 (en) 2018-06-09 2020-06-30 Honeywell International Inc. System and methods for mitigating condensation in a sensor module
WO2023012019A1 (fr) * 2021-08-05 2023-02-09 Truma Gerätetechnik GmbH & Co. KG Brûleur à élément de commande et à électrode d'allumage et d'ionisation et procédé de surveillance et d'allumage de la flamme d'un brûleur

Also Published As

Publication number Publication date
DE4309454C2 (de) 1997-03-06
DE4309454A1 (de) 1994-09-29

Similar Documents

Publication Publication Date Title
EP0617234A1 (fr) Détecteur de flamme à ionisation
DE4005609B4 (de) Verfahren und Vorrichtung zur Funktionsüberwachung eines elektrischen Verbrauchers
DE10021569B4 (de) Fehlzündungserfassungsvorrichtung und -verfahren für Verbrennungsmotoren
DE19733869A1 (de) Vorrichtung zur Feststellung des Verbrennungszustands einer Brennkraftmaschine
DE2343895A1 (de) Verfahren und einrichtung zur ueberpruefung der zuendanlage von brennkraftmaschinen
EP0999956B1 (fr) Dispositif et procede pour essayer un montage servant a commander un moyen de protection d'occupant d'un vehicule automobile
DE2848466A1 (de) Batterieladevorrichtung
DE3347459C2 (fr)
EP1089899B1 (fr) Dispositif de declenchement d'un dispositif de protection des occupants d'un vehicule a moteur
DE10250387B4 (de) Verbrennungszustands-Erfassungsvorrichtung
DE69412039T2 (de) Verfahren und Vorrichtung einer Spulenzündung mit zusätzlichen Entladungen zur Diagnose
DE2545325B2 (de) Schaltungsanordnung zur Messung des Isolationswiderstandes erdfreier Starkstromschaltungen
DE102004043455B4 (de) Methode zur Diagnose einer offenen Sekundärwicklung einer Zündspule mit Hilfe des Signals für den Ionisations-Strom
DE4112996A1 (de) Vorrichtung und verfahren zur funktionsueberwachung eines elektrischen verbrauchers
DE4122636A1 (de) Vorrichtung und verfahren zum ueberwachen einer flamme
EP0898368A2 (fr) Dispositif capteur
DE4232720C1 (de) Anordnung zur Funktionsüberwachung und Meßwertauswertung von Füllstands-Sensoren, insbesondere Vibrations-Füllstands-Grenzschaltern
EP2117094B1 (fr) Commutation de surveillance et procédé de contrôle d'une commutation
DE19826704C1 (de) Vorrichtung zum Zünden eines Zündelements eines Kraftfahrzeug-Insassenschutzmittels
DE69014933T2 (de) Vorrichtung für die Zündungserkennung bei einer Zündungseinrichtung.
EP0635638B1 (fr) Circuit de détection de flamme
DE3219236C2 (fr)
DE19836361C1 (de) Verfahren zur Leckstromprüfung einer Kontaktierungsstelle einer integrierten Schaltung
DE19829583C1 (de) Verfahren und Vorrichtung zur Bestimmung der Durchbruchspannung bei der Zündung einer Brennkraftmaschine
DE3306431C2 (de) Einrichtung zur Erkennung von Zündaussetzern

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LI NL

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: KARL DUNGS GMBH & CO.

17P Request for examination filed

Effective date: 19950310

17Q First examination report despatched

Effective date: 19960221

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19970419