EP1039225A2 - Ventileinheit zur Regelung des Durchflusses von Brenngas - Google Patents

Ventileinheit zur Regelung des Durchflusses von Brenngas Download PDF

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Publication number
EP1039225A2
EP1039225A2 EP99202114A EP99202114A EP1039225A2 EP 1039225 A2 EP1039225 A2 EP 1039225A2 EP 99202114 A EP99202114 A EP 99202114A EP 99202114 A EP99202114 A EP 99202114A EP 1039225 A2 EP1039225 A2 EP 1039225A2
Authority
EP
European Patent Office
Prior art keywords
pressure
unit according
valve
motor
closure element
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Withdrawn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
EP99202114A
Other languages
English (en)
French (fr)
Other versions
EP1039225A3 (de
Inventor
Giuseppe Veronese
Stefano Fandella
Salvatore Pappalardo
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.)
Sit La Precisa SpA
Original Assignee
Sit La Precisa SpA
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 Sit La Precisa SpA filed Critical Sit La Precisa SpA
Publication of EP1039225A2 publication Critical patent/EP1039225A2/de
Publication of EP1039225A3 publication Critical patent/EP1039225A3/de
Withdrawn legal-status Critical Current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
    • F23N1/007—Regulating fuel supply using mechanical means
    • 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
    • F23N5/10—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples
    • F23N5/102—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2235/00—Valves, nozzles or pumps
    • F23N2235/12—Fuel valves
    • F23N2235/16—Fuel valves variable flow or proportional valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2235/00—Valves, nozzles or pumps
    • F23N2235/12—Fuel valves
    • F23N2235/20—Membrane valves

Definitions

  • the invention relates to a valve unit for regulating the flow-rate of a fuel gas, according to the preamble to the main claim.
  • valve units of this type are used for regulating the flow-rate of a fuel gas delivered to a burner or to another similar user through a delivery duct.
  • Units are known, in which the gas-flow is regulated by controlled regulation of the delivery pressure between minimum and maximum pressure values by means of a servo-valve subservient to a modulation unit with diaphragm control.
  • the diaphragm of a unit of this type is acted on, on one side, by the gas delivery pressure as detected in the delivery duct to the user and, on the other side, by a resilient load which is subjected to the action of the movable element of an electromagnetic actuator.
  • the delivery pressure can thus be modulated in a manner correlated with the electrical current which is supplied to the solenoid of the electromagnetic actuator and which is variable between a minimum value and a maximum value.
  • the actuators provided for operating the closure element associated with this outlet aperture particularly the electromagnetic actuators normally used in gas technology, have the same disadvantages as indicated above and are not therefore well suited to applications in which a high degree of accuracy is required in the modulation of the flow-rate of the gas delivered.
  • the problem upon which the present invention is based is that of providing a device for regulating the flow-rate of a gas which is designed structurally and functionally to prevent all of the problems complained of with reference to the prior art mentioned.
  • valve unit for regulating the flow-rate of a fuel gas delivered to a burner or to another similar user, not shown in the drawing, is generally indicated 1.
  • the gas is supplied to the unit 1 through a supply duct 2 and is delivered thereby through a delivery duct 3.
  • the ducts 2 and 3 are separated by a servo-valve 4 comprising a closure element 5 which is acted on resiliently so as to close a seat 6 by the resilient load of a spring 7, and which can be opened by a diaphragm 8 which is sensitive to the pressure differential existing between the pressure Pu in the delivery duct 3 on one side and the pressure value Pt in a control chamber 9 on the other side.
  • the pressure value Pt is controlled by means of a diaphragm pressure-modulation valve, indicated 10, which, with the servo-valve 4, constitutes a servo-assisted diaphragm pressure-regulator device.
  • the modulation valve 10 comprises an operating rod 11 one axial end of which is screwed into a cup-shaped element 12.
  • a spring 13 acts between the cup-shaped element 12 and a plate 14 carrying a closure element 15 which can shut off a seat 16.
  • the plate 14 is fixed to a modulation-valve diaphragm 17 which is subjected to the load exerted by the operating rod 11 on one side and to the pressure existing in a chamber 18 on the other side.
  • the chamber 18 is in communication with the delivery duct 3 by means of a transfer duct 19 and with a second chamber 20 by means of the valve seat 16.
  • the second chamber 20 is always in communication with the control chamber 9 by means of a second transfer duct 21, whereas it communicates selectively with a tapping-off duct 22 for the gas supplied to the input of the valve unit and with a duct 23 opening into the chamber 18 via an on-off valve generally indicated 24.
  • the on-off valve 24 comprises a closure element 25 which is acted on so as to close a seat 26 and is movable so as to close an opposed seat 27 so that the seats 26, 27 are opened or closed alternatively by the operation of the on-off valve.
  • a choke 22a such as to bring about a loss of pressure in order to derive the control pressure Pt from a fraction of the gas-flow tapped off from the flow supplied through the duct 2 at the input of the valve unit.
  • the operating rod 11 has a male thread 28 which can be engaged by screwing in a female thread 29 formed inside a bush 30.
  • the bush 30 is connected rigidly and coaxially to the rotor 31 of an electric motor 32 associated with the valve 10.
  • the motor 32 is a direct-current electric motor and is preferably a stepper motor.
  • the operating rod 11 is connected to the hollow shaft of the rotor 31 by the male-and-female screw coupling with a unitary transmission ratio.
  • the operating rod 11 also has a pair of diametrally-opposed, radial projections 33 for engaging respective grooves 34 formed in a casing 35 of the motor connected rigidly to the stator portion of the motor.
  • the threaded operating rod 11 is guided in the direction of its axis in a manner such that, by virtue of the male-and-female screw coupling, a rotation of the bush 30 causes corresponding axial sliding of the rod 11 with a consequent variation in the resilient load generated on the spring 13 and in turn produced on the diaphragm 17.
  • a spring 36 acts between the cup-shaped element 12 and the casing 35 (which is fixed to the stator portion of the motor) and serves to keep the corresponding sides of the thread of the male-and-female screw coupling continuously in contact with one another, thus eliminating the play which is present in the coupling.
  • An adjustable stop element is formed on the surface of a screw 38 screwed into an axial threaded hole 39 of the casing of the motor 32.
  • a safety solenoid valve, generally indicated 40, is disposed upstream of the valve unit 1 and serves to shut off the main gas-flow supplied through the duct 2.
  • the operating rod 11 is moved axially between a first position in which it is in abutment with the stop element 37 in order to produce a minimum resilient load on the spring 13 and consequently a minimum delivery-pressure value Pu, and a second position in which the rod is moved so as to compress the spring in order to produce a preselected maximum resilient load correlated to the maximum permissible delivery pressure value Pu for the modulator valve.
  • the motor 32 is rotated for a preselected number of revolutions, this number of revolutions being correlated, by means of the pitch of the thread in the male-and-female screw coupling, with a predetermined axial travel of the operating rod.
  • the travel performed by the rod is such as to produce a resilient load in the spring 13 which in turn is correlated proportionally with the delivery pressure Pu produced in the delivery duct 3 by the modulation valve 10, as explained in greater detail in the following description.
  • the resilient load of the spring 13 presses on the diaphragm 17 which partially closes the closure element 15 onto the corresponding seat 16.
  • This partial closure brings about an increase in the pressure Pt existing in the chamber 20 and, via the transfer duct 21, in the control chamber 9.
  • This increased pressure Pt acts on the diaphragm 8, urging the closure element 5 to open.
  • the partial opening of the closure element 5 leads to an increase in the delivery pressure Pu.
  • This pressure Pu also acts, via the duct 19, on the side of the diaphragm 17 facing the chamber 18, consequently balancing the resilient load exerted by the spring 13.
  • the value of the delivery pressure Pu thus achieved is correlated with the flow-rate delivered through the delivery duct 3.
  • a pressure value Pu and a flow-rate which are proportionally correlated with one another are thus achieved for each value of the resilient load exerted on the diaphragm 17 (which is proportional to the number of revolutions performed by the rotor 31).
  • the flow-rate of gas can thus be regulated continuously by the operation of the motor 32 associated with the modulation valve 10.
  • the motor 32 has a rotor 31 the rotation of which is reversible, so that the gas-delivery pressure can be modulated continuously from the maximum value to the minimum value and vice versa as a result of the rotation of the rotor 31 in one direction of rotation or in the opposite direction, respectively.
  • FIG. 2 shows a second embodiment of the valve unit of the invention, generally indicated 50, in which parts corresponding to those of the previous embodiment are indicated by the same reference numerals.
  • the valve unit 50 differs form the unit 1 in that, instead of the modulation valve 10 of the unit 1, it has a regulation valve 51 comprising a screw 52 for regulating the maximum value of the pressure Pu.
  • the screw 52 with which the spring 13 is in abutment, maintains a preselected resilient load on the diaphragm 17, this load being correlated proportionally with a delivery pressure Pu in the duct 3.
  • the pressure Pu is the pressure detected through the duct 19.
  • the unit 50 also comprises means for choking the delivery duct 3, the means comprising a closure element 53 which is acted on so as to close a gas outlet aperture 54.
  • the aperture 54 is formed in a plate-like partition 55 ( Figure 4) which is mounted in the duct 3 and against which the closure element 53 bears.
  • the closure element comprises a first plate-shaped portion 53a which is acted on resiliently so as to close the aperture 54.
  • the plate-shaped portion 53a is connected to a second, bent portion 53b constituting a resilient means which in turn is extended by a third portion 53c extending from the second portion ( Figures 6 and 7) at right angles.
  • the third portion 53c has opposed appendages 53d which extend in the same direction from a central portion 53e and by means of which the closure element is connected rigidly to the outer wall of a bush 56.
  • the axial cavity of the bush 56 has a female thread 57 which can be engaged by screwing on an externally threaded rod 58 connected rigidly to the rotor 31 of the motor 32.
  • the rod 58 is preferably connected to the shaft of the rotor 31 by means of a coupling 59 keyed to the motor shaft and having an axial projection 59a shaped like the tip of a flat-bladed screwdriver and housed in a corresponding seat of the rod.
  • the end of the rod remote from the coupling 59 is housed in a recess 60 formed in the body of the valve unit 1.
  • a spring 61 acting between the bush 56 and the stator portion of the motor serves to take up the play in the male-and-female threaded coupling in exactly the same manner as described in the previous embodiment.
  • the bush 56 and the closure element 53 fixed thereto are moved axially between a first position in which the aperture 54 is completely shut off by the portion 53a of the closure element and a second position to which the closure element is moved so as to open the aperture completely.
  • the portion 53c for attaching the closure element to the bush 56, preventing the bush from rotating about its own axis also constitutes guide means for guiding the axial movement of the bush due to the male-and-female threaded coupling, as a result of the rotation of the rod 58 about its axis.
  • the portion 53b is pivoted towards the portion 53a and serves to exert on the latter a resilient load to keep the closure element in continuous sliding contact with the outlet aperture 54 during the movement of the closure element 53 from the first position to the second.
  • a bush, indicated 62, for adjusting the minimum value of the travel of the closure element 53 is screwed onto a portion of the body of the valve unit 1.
  • the motor 32 is rotated for a preselected number of revolutions, this number of revolutions being correlated proportionally, by means of the pitch of the thread in the male-and-female screw coupling, with the axial travel of the closure element 53 and consequently with the choking of the outlet aperture 54.
  • a value of the outlet cross-section and consequently of the flow-rate delivered, which are correlated with one another proportionally, is thus achieved for each positioning of the closure element 53 between the first and the second position (this positioning being proportional to the number of revolutions performed by the rotor 31).
  • the flow-rate of gas can thus be modulated continuously by control of the motor 32 associated with the valve for choking the delivery duct 3.
  • the motor 32 has a rotor the rotation of which can be reversed so that the flow-rate of gas can be modulated continuously from the maximum value to the minimum value and vice versa as a result of the rotation of the rotor 31 in one direction of rotation or in the opposite direction, respectively.
  • the aperture 54 preferably has a triangular shape ( Figure 4) in which a straight or curved shape is selected for at least two sides ( Figure 5) to achieve different values for the flow-rate of gas delivered for a given positioning of the closure element.
  • the invention thus solves the problem set, achieving the advantages mentioned above in comparison with known solutions.
  • valve unit of the invention achieves greater accuracy in the modulation of the gas flow-rate than known devices in which mechanical and magnetic hystereses lead to errors in the positioning of the operating rod of the pressure regulator or of the closure element in the delivery duct.
  • the unit according to the invention advantageously enables a clearly defined pressure value and/or flow-rate to be achieved for each value of the positioning travel of the operating rod of the pressure regulator or of the closure element in the delivery duct.
  • valve unit according to the invention also leads to the advantage that the range of regulatable pressures can be widened and it is thus possible to regulate minimum pressures lower than those which can be regulated by known units.
  • minimum pressures of the order of about 1% of the maximum permissible pressures can be regulated, with minimum powers consequently of the order of 10% of the maximum powers.
  • a further advantage is that these minimum powers which can be achieved, which are lower than the values achieved by known solutions (for given maximum powers achieved by known devices), enable a minimal combustion to be maintained in the equipment, avoiding frequent cycles of extinguishing/ lighting of the gas, achieving a considerable reduction in harmful emissions of exhaust gases which, as is well known, increase with frequent lighting and extinguishing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Feeding And Controlling Fuel (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrically Driven Valve-Operating Means (AREA)
  • Fluid-Driven Valves (AREA)
EP99202114A 1999-03-23 1999-06-29 Ventileinheit zur Regelung des Durchflusses von Brenngas Withdrawn EP1039225A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1999PD000058A IT1308112B1 (it) 1999-03-23 1999-03-23 Gruppo valvolare per la regolazione della portata di un gascombustibile.
ITPD990058 1999-03-23

Publications (2)

Publication Number Publication Date
EP1039225A2 true EP1039225A2 (de) 2000-09-27
EP1039225A3 EP1039225A3 (de) 2002-05-08

Family

ID=11392524

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99202114A Withdrawn EP1039225A3 (de) 1999-03-23 1999-06-29 Ventileinheit zur Regelung des Durchflusses von Brenngas

Country Status (4)

Country Link
EP (1) EP1039225A3 (de)
DE (1) DE1039225T1 (de)
ES (1) ES2151874T1 (de)
IT (1) IT1308112B1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6938634B2 (en) 2003-05-30 2005-09-06 Robertshaw Controls Company Fuel control mechanism and associated method of use
US6941962B2 (en) 2003-05-30 2005-09-13 Robertshaw Controls Company Convertible control device capable of regulating fluid pressure for multiple fluid types and associated method of use
EP2327931A3 (de) * 2009-11-30 2015-02-18 Whirlpool Corporation Verfahren und Vorrichtung zur Bereitstellung einer niedrigen Gasbrennerleistung für ein Kochgerät
CN108644412A (zh) * 2018-07-19 2018-10-12 宁波丽辰电器有限公司 一种分流阀，及包含其的多燃烧器燃气具的组合控制系统

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT395210B (de) * 1987-12-11 1992-10-27 Vaillant Gmbh Gasdruck-regelventil fuer gasbeheizte geraete
US5238398A (en) * 1991-06-17 1993-08-24 Harmony Thermal Company, Inc. Variable orifice gas modulating valve
EP0562538B1 (de) * 1992-03-26 1998-08-26 Matsushita Electric Industrial Co., Ltd. Gasgerät
IT1293697B1 (it) * 1997-04-30 1999-03-10 Op Srl Ora Op Controls S R L Unita' valvolare di sicurezza e regolazione per un impianto a gas particolarmente un impianto di riscaldamento

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6938634B2 (en) 2003-05-30 2005-09-06 Robertshaw Controls Company Fuel control mechanism and associated method of use
US6941962B2 (en) 2003-05-30 2005-09-13 Robertshaw Controls Company Convertible control device capable of regulating fluid pressure for multiple fluid types and associated method of use
EP2327931A3 (de) * 2009-11-30 2015-02-18 Whirlpool Corporation Verfahren und Vorrichtung zur Bereitstellung einer niedrigen Gasbrennerleistung für ein Kochgerät
CN108644412A (zh) * 2018-07-19 2018-10-12 宁波丽辰电器有限公司 一种分流阀，及包含其的多燃烧器燃气具的组合控制系统
CN108644412B (zh) * 2018-07-19 2024-04-19 宁波丽辰电器有限公司 一种分流阀，及包含其的多燃烧器燃气具的组合控制系统

Also Published As

Publication number Publication date
ITPD990058A1 (it) 2000-09-23
IT1308112B1 (it) 2001-11-29
ES2151874T1 (es) 2001-01-16
DE1039225T1 (de) 2001-06-07
EP1039225A3 (de) 2002-05-08

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