EP0327516A1 - Device for the automatic control of combustion air flow drawn into forced draught boilers by means of an electroventilator - Google Patents

Device for the automatic control of combustion air flow drawn into forced draught boilers by means of an electroventilator Download PDF

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Publication number
EP0327516A1
EP0327516A1 EP89830040A EP89830040A EP0327516A1 EP 0327516 A1 EP0327516 A1 EP 0327516A1 EP 89830040 A EP89830040 A EP 89830040A EP 89830040 A EP89830040 A EP 89830040A EP 0327516 A1 EP0327516 A1 EP 0327516A1
Authority
EP
European Patent Office
Prior art keywords
diaphragm
fitted
electric fan
combustion air
forced draught
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Withdrawn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
EP89830040A
Other languages
German (de)
English (en)
French (fr)
Inventor
Lino Natalini
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0327516A1 publication Critical patent/EP0327516A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N1/00—Regulating fuel supply
    • F23N1/02—Regulating fuel supply conjointly with air supply
    • F23N1/025—Regulating fuel supply conjointly with air supply using electrical or electromechanical means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2233/00—Ventilators
    • F23N2233/06—Ventilators at the air intake
    • F23N2233/08—Ventilators at the air intake with variable speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/18—Systems for controlling combustion using detectors sensitive to rate of flow of air or fuel

Definitions

  • This application for an industrial patent relates to a device for the automatic control of the combustion air delivery in modern boilers, fitted with an air-tight or non air-tight combustion chamber, having a forced draught with combustion air drawn either directly from outside or from the room in which the boiler is installed.
  • modulating fuel-gas distribution valves are also used in boilers with air-tight or non air-tight chamber, capable of decreasing the gas supply gradually in the burner as the temperature of the back-flow water in the boiler increases to reach the temperature set on the thermostat.
  • the electric fan which is usually fitted after the combustion chamber, in drawing the fumes by forced draught, creates a depression in the boiler which helps the suction of the combustion air.
  • the electric fan currently used on boilers is not fitted with any automatic control device capable of varying the delivery of the drawn air according to the fuel-gas supplied to the burner by the modulating distribution valves with the resulting problem of a fuel mixture having an excess of combustion air which increases as the fuel-gas supplied decreases by means of the modulating action of the distribution valves.
  • the object of this invention is therefore that of developing a device capable of automatically controlling the delivery of the combustion air by varying the revs of the electric fan according to the gas delivery supplied by the modulating distribution valves in order to maintain the air-to-fuel ratio of the mixture to the burner, constant and obviously equal to the optimum value.
  • the device according to the invention includes a diaphragm held between two circular half-shells, on the two sides of which the fluid pressure before and after the electric fan acts, in that another diaphragm, smaller than the other and held between the above half-shell and an external casing having a pressure which is always the same as the pressure of the fuel-gas measured before the supplying nozzles, is fitted parallel to the first in the half-shell communicating with the section, under depression, before the electric fan.
  • a sleeve is fitted on the internal side of the smaller diaphragm, whose edge opposes a series of radial levers supported at the ends which discharge the axial thrust from the sleeve by means of the above radial levers, on a collar fitted on the axial rod which crosses the larger diaphragm on which an optical barrier is fitted and whose axial position, obviously resulting from the pressure on the two above diaphragm, is read by an optical detector which regulates the rotation speed and consequently also the air delivery drawn by the electric fan.
  • This technical feature makes it possible to rate the device in question according to the boiler in which it is to be installed, in that the differential pressure generated by the electric fan varies both with respect to the electric fan model and to the characteristics of the system in which the electric fan is to operate.
  • the thrust transmitted by the smaller diaphragm to the larger diaphragm, for the same force exerted by the above sleeve, can be regulated simply by changing the position of the lever pivots so as to vary the ratio between the axial thrust of the smaller diaphragm and that of the larger diaphragm, as necessary.
  • the device according to the invention includes a circular diaphragm (1) fitted between two partially rigid plates (1a), held along the perimeter by two circular half-shells (2) and (3), the first (2) communicating with a section of the exhaust pipe fitted immediately after the electric fan, the other (3) with a section fitted before.
  • a second smaller circular diaphragm (4) which is held along the perimeter between the semi-shell (3) and an external casing (5) communicating with the supply pipes of the fuel-gas, is fitted parallel and coaxially to the above diaphragm (1).
  • a sleeve (6) On the internal wall of the smaller diaphragm (4) a sleeve (6) is fitted whose edge opposes a coplanar series of radial levers (7) whose ends are supported respectively and peripherally on support and pivot points (F), at the centre, on a collar (8) fitted in and integrally with a rod (9), fixed axially on the larger diaphragm (1).
  • a barrier (10) is fitted along the rod (9) in the section in the half-shell (2), which according to the axial position assumed, totally or partially intercepts an optic flow emitted by a photo-emitter (10a) and detected by a photo-detector (10b) fitted on the internal surface of the half-shell (2).
  • An opposing element (11) is also fitted along the rod (9), which in its axial stroke integrally with the rod (9), intercepts the moving element (12) of an electric switch resulting in an exchange of the electrical contacts (13) for starting and stopping the fuel-gas supply.
  • the contact-holder (13) casing fixed outside the half-shell (2) is indicated as number (14).
  • the translation of the rod (9) integrally with the diaphragm (1) corresponds to an equivalent movement of the opposing element (11), in that it no longer interferes with the moving element (12) thereby allowing the latter to carry out, under the thrust of the release spring (16), the exchange of electrical contacts (13) so as to start the gas supply system electrically, whose pressure also acting on the external face of the small diaphragm (4) generates an axial thrust which balances the force on the diaphragm (1) thanks to the appropriate sizing of the areas of the two diaphragms and to the rating of the device (correct positioning of pivots F), as a result of the difference of pressure between the two half-shells (2) and (3).
  • the optical unit activated after the electrical contact of the boiler (thermostat) is closed, regulates the electric circuit which controls the rotation speed of the electric fan, by means of the so-called “loop” and keeps the system balanced.
  • the optical barrier (10) is moved axially together with diaphragms (1 and 4) resulting in the interception of a greater part of the optical flow between the emitter (10a) and the photo-­detector (10b) with a consequent increasing variation of the current transmitted to the electric fan motor.
  • the device according to the invention can control the combustion air delivery according to the delivery of the fuel-gas, maintaining the value of the air-to-fuel ratio, constant.
  • the device according to the invention can also act as a safety device for stopping the supply of gas should the fume discharge pipe accidentally become plugged.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Regulation And Control Of Combustion (AREA)
EP89830040A 1988-02-05 1989-02-06 Device for the automatic control of combustion air flow drawn into forced draught boilers by means of an electroventilator Withdrawn EP0327516A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT00603/88A IT1220226B (it) 1988-02-05 1988-02-05 Dispositivo per la regolazione automatica della protata d'aria comburente aspirata nelle caldaie a tiraggio forzato,a mezzo di elettroventilatore
IT60388 1988-02-05

Publications (1)

Publication Number Publication Date
EP0327516A1 true EP0327516A1 (en) 1989-08-09

Family

ID=11290691

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89830040A Withdrawn EP0327516A1 (en) 1988-02-05 1989-02-06 Device for the automatic control of combustion air flow drawn into forced draught boilers by means of an electroventilator

Country Status (2)

Country Link
EP (1) EP0327516A1 (it)
IT (1) IT1220226B (it)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0664422A1 (de) * 1994-01-25 1995-07-26 Karl Dungs GmbH & Co. Verbunddruckwächter
US5968320A (en) * 1997-02-07 1999-10-19 Stelco, Inc. Non-recovery coke oven gas combustion system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3119270A (en) * 1961-02-02 1964-01-28 Ronald G Wayne Adjustable range transducer
DE2011717A1 (de) * 1969-05-30 1970-12-03 Joh. Vaillant Kg, 5630 Remscheid Regelvorrichtung für gas- oder ölbeheizte Heizgeräte
US3590259A (en) * 1970-04-20 1971-06-29 Kinemotive Corp Chopper stabilized photoelectric transducer
FR2353801A1 (fr) * 1976-06-02 1977-12-30 Saunier Duval Systeme de securite et de controle du debit d'air necessaire a la combustion d'un bruleur a gaz
FR2515314A1 (fr) * 1981-10-23 1983-04-29 Seccacier Procede et installation pour reguler le fonctionnement d'une chaudiere a gaz
US4464936A (en) * 1982-08-03 1984-08-14 Fike Metal Products Corporation Monitoring apparatus for pressure sensitive devices

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3119270A (en) * 1961-02-02 1964-01-28 Ronald G Wayne Adjustable range transducer
DE2011717A1 (de) * 1969-05-30 1970-12-03 Joh. Vaillant Kg, 5630 Remscheid Regelvorrichtung für gas- oder ölbeheizte Heizgeräte
US3590259A (en) * 1970-04-20 1971-06-29 Kinemotive Corp Chopper stabilized photoelectric transducer
FR2353801A1 (fr) * 1976-06-02 1977-12-30 Saunier Duval Systeme de securite et de controle du debit d'air necessaire a la combustion d'un bruleur a gaz
FR2515314A1 (fr) * 1981-10-23 1983-04-29 Seccacier Procede et installation pour reguler le fonctionnement d'une chaudiere a gaz
US4464936A (en) * 1982-08-03 1984-08-14 Fike Metal Products Corporation Monitoring apparatus for pressure sensitive devices

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, vol. 9, no. 70 (M-367)[1793], 30th March 1985; & JP-A-59 202 319 (MATSUSHITA DENKI SANGYO K.K.) 16-11-1984 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0664422A1 (de) * 1994-01-25 1995-07-26 Karl Dungs GmbH & Co. Verbunddruckwächter
US5968320A (en) * 1997-02-07 1999-10-19 Stelco, Inc. Non-recovery coke oven gas combustion system

Also Published As

Publication number Publication date
IT1220226B (it) 1990-06-06
IT8800603A0 (it) 1988-02-05

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