GB2352804A

GB2352804A - Method and apparatus for modulating gas flow to a burner

Info

Publication number: GB2352804A
Application number: GB0016765A
Authority: GB
Inventors: Maurizio Grando; Michele Bortoliero; Giovanni Belladore
Original assignee: O P CONTROLS SpA; OP Controls Srl
Current assignee: O P CONTROLS SpA; OP Controls Srl
Priority date: 1999-07-19
Filing date: 2000-07-08
Publication date: 2001-02-07
Also published as: IT1307214B1; ITPD990170A1; GB0016765D0

Abstract

In the method the flow-rate of gas to the burner 3 is modulated over time by means of a programmer 9 in a manner variable in accordance with a preselected rule. The apparatus comprises a valve 5 and an actuator 6 which acts in accordance with a pre-selected rule set by the programmer. The rule may be changed and may include a sequence to mimic the lighting, burning and subsequent dying down of burning wood or coal.

Description

2352804 A method of modulating the flame in a fuel-gas burner and

apparatus operating in accordance with the method DESCRIPTION

The present invention relates to a method of modulating the flame in a fuel-gas burner according to the preamble to the main claim, and to apparatus operating in accordance with the method.

The invention is suitable particularly but not exclusively for modulating the flame in room-heating apparatus and, more particularly, the invention is applicable to gas stoves which are used for decorative purposes as well as for heating.

Stoves of this type typically have a gas burner for generating a flame of an essentially decorative nature simulating a flame of burning wood or coal. For this purpose, it is necessary to modulate the flame in order to simulate the stages of combustion from the stage of gradual lighting of the flame, through a stage of maximum flame, to the stage at which the f lame dies out.

Within this specific field, the modulation of the flame is achieved by modulation of the flow-rate of gas supplied to the burner of the stove. It is known to modulate the flow-rate by acting manually on the gas-supply valve either directly or by indirect action by means of remote control devices. However, these systems require deliberate operation by the user who can vary the gas flow-rate by operating the gas-supply valve as desired.

It is also known to use devices f or modulating the gas flow-rate which provide for the use of thermostats sensitive to the ambient temperature and capable of varying the f lowrate of gas supplied to the burner in dependence on the 2 ambient temperature detected by the thermostat. In this case, the alternation of the simulated combustion stages is controlled in dependence on the variation of the ambient temperature detected by the regulation thermostat.

The main object of the present invention is to propose a method of modulating the burner flame over time, independently of deliberate or precise operation by the user and of regulation achieved in dependence on ambient temperature.

This object is achieved by the invention by a method of modulating the flame of a burner achieved in accordance with

Claims

appended Claims I to 4. The invention also relates to apparatus operating

in accordance with the method of the invention, formed in accordance with Claims 5 and 6. The characteristics and the advantages of the invention will become clearer from the following detailed description of a preferred embodiment thereof, described by way of nonlimiting example with reference to the single appended drawing which is a diagram of the functioning of apparatus operating in accordance with the method of the invention.

With reference to the drawing mentioned, apparatus for modulating, in accordance with the method of the present invention, the flame in a stove
2 having a decorative function in addition to that of heating rooms, is generally indicated 1.

The stove 2 has a burner
3 supplied with a fuel gas delivered by a valve unit 5 through a pipe
4. The valve unit comprises a closure element which is movable to close a valve seat in the supply pipe 4, both the closure element and the valve seat, which are not shown, being of a conventional configuration. An actuator, generally 3 indicated 6 and shown schematically in the drawing, is provided for opening and/or closing the closure element.

The burner 3 is also associated with a f lame detector 7, operatively connected to the valve unit 5, f or monitoring the presence of f lame in the burner. A secondary pipe 8 is provided f or supplying the gas to a pilot burner, not shown, which is associated with the main burner 3 and the lighting of which is monitored by the flame detector 7.

According to a principal characteristic of the method of the invention, the f lame of the burner 3 can be modulated over time as a result of the modulation of the flow-rate Q of gas supplied to the burner. For this purpose, the apparatus 1 comprises a programmer device 9 operatively connected to the actuator 6. The method provides for the setting, in the programmer 9, of flow-rate values Q of a preselected rule for the variation of the flow-rate over time, and for the subsequent conversion of these values into a sequence of respective control signals which are sent to the actuator 6 in order correspondingly to control the closure element of the valve unit
5 so as to vary the f lowrate Q supplied over time, in accordance with the abovementioned rule of variation, and consequently to modulate the f lame in the burner in a correlated manner.

There is also provision for the flow-rate values of the preselected rule of variation to be programmable and, more particularly, the method provides f or programing of the behaviour of the f low-rate Q over time, within a series of periods of time arranged in sequence. A f irst period, f or example is distinguished by flow-rate values increasing between a minimum value and a maximum value, simulating the stage of the lighting of the f lame in the stove. In a 4 second period the flow-rate is arranged to be kept constantly at its maximum value, simulating the presence of live flame, whilst a third period is distinguished by decreasing values of the flow-rate to a minimum value 5 thereof, simulating the progressive dying-down of the flame. In a fourth period, the flow-rate value is kept equal to its minimum value, simulating, for example, the presence of embers without any live flame in the stove and, finally, in a fifth period, the flow- rate values are arranged to decrease to zero to simulate complete and gradual dying-out of the flame in the stove.

The method of the invention provides for programming of the flow-rate values, of the durations of the abovementioned periods of time, and of the sequence and alternation of the periods. As a result, it is possible to set, in the programmer 9, a preselected rule for the variation of the flow-rate Q over time, simulating the life of the flame in the stove, and to produce a signal f or controlling the actuator 6 in order to supply this flow-rate Q to the burner 3.

Naturally, the preselected rule may provide for all or only some of the time periods described above, according to the user's choice. A selector device 10 associated with the programmer 9 is provided for selecting the desired sequence.

The method also provides for programming of a plurality of rules for the variation of the flow-rate, each of which is characteristic of a respective flame modulation function, and which can be selected by the user as desired. The method provides for the programmer to be electronic.

Alternatively, an exclusively mechanical programmer 9 or an electromechanical programmer 9 may be used.

In an alternative embodiment of the invention, a modulation element, indicated 11 in the drawing, may be provided in the apparatus 1 for performing the function of modulating the flow-rate of gas previously performed by the actuator 6, separately from the safety function of the valve unit 5.

The invention thus solves the problem set, achieving many advantages over known arrangements. In particular, there is the advantage that the flame in decorative gas stoves is modulated, simulating the burning of wood, in accordance with preselected behaviour over time, independently of direct (manual) or indirect operation of the valve unit by the user and independently of thermostatic regulation. In the second place, the method and the apparatus of the invention enable a preselected rule for the variation of the flow-rate of gas to be programmed as desired in order automatically to modulate the flame of the stove in a corresponding correlated manner. A further advantage is that of being able to select a rule f or the modulation of the flow-rate over time from a plurality of preset rules each of which is characteristic of the simulation of a particular behaviour of the flame of the stove over time.
6. Apparatus according to Claim 5, in which the programmer is mechanical, electronic or electromechanical.

6 CLAIMS 1. A method of modulating the flame of a fuel-gas burner, characterized in that the f low-rate of gas to the burner is modulated over time by means of a programmer in a 5 manner variable in accordance with a preselected rule.

2. A method according to Claim 1, in which the rule of variation is substantially independent of a thermostatic regulation.

3. A method according to Claim 1 or Claim 2, in which the programmer of the rule of variation of the flow-rate is mechanical, electronic or electromechanical.

4. A method according to one or more of the preceding claims, in which the programmer is arranged to implement a plurality of the said rules of variation which can be selected at will.

5. Apparatus for modulating the flow-rate of a fuel gas, comprising valve means for supplying the flow to a burner and actuator means for operating the valve means, characterized in that the actuator means comprise a programmer which acts on the valve means in order to vary the flow-rate of gas supplied to the burner in accordance with a preselected rule of variation over time.