GB2070230A - Movable gas-heater incorporating a gas bottle - Google Patents

Abstract

This invention relates to a gas- heater incorporating a bottle and wherein a safety valve, controlled by a pilot burner, is provided in the pipe connecting the bottle to the burner. A thermostatic valve (7) is provided between the safety valve (6) and the burner (4) for the purpose of regulating the heating programme on an 'all or nothing' or 'all or little' basis as a function of the ambient temperature. Application: provision of an automatically controlled heating programme. <IMAGE>

Description

SPECIFICATION Movable gas-heater incorporating a gas bottle The present invention relates to a movable gas-heater and in particular but not exclusively, to a movable gas-heater incorporating a butane bottle, the gases of combustion not being discharged into the atmosphere.

This type of apparatus is well-known and is used on a large scale throughout the world. A movable heater incorporating a butane bottle is constituted by a housing for concealing the bottle, and a heating unit which may be an ordinary flame burner, an infra-red burner or a catalytic panel permitting flameless combustion, the housing for concealing the bottle generally being mounted on rollers.

During the course of their development, such items of apparatus have been the subject of numerous improvements concerning safety in operation or ease of use.

Normally, a thermo-electrical safety device, comprising a thermocouple, heated by the main burner or a pilot burner, cuts off the inflow of the gas in the event of accidental extinction of the flame. Such apparatus also comprises a device for providing safety against the atmosphere, which is formed by means of a metastable pilot device, the flame of which blows out when the oxygen in the room in which the apparatus is located becomes rarefied, this pilot device, in conjunction with the thermocouple, cutting off the gas when the flame goes out. These installations may be equipped with automatic piezoelectric ignition means.A post-catalysis device is provided in the most highly developed models, and the gases of combustion of a flame burner or infra-red burner are caused to pass through a catalytic screen formed by a platinum-coated asbestos cloth which enables combustion to be carried out completely and prevents any release of unburnt gas or carbon monoxide.

By comparison with other heating methods, heating by movable units offers numerous advantages, resulting in particular from the ease with which they can be installed, their complete reliability, their heating power, their energy output and their low cost.

Nevertheless, the present heaters still suffer from certain drawbacks, and in particular the infra-red burners and the catalytic panels function truly correctly only when operating approximately at their nominal power. Consequently, it is not easy to construct such apparatus in such a way that the heating power can be very finely regulated. By dividing up the burners it is possible, by means of suitable cocks and valves, to carry out regulating in stages, but the user is obliged to take action to increase or reduce the heating rate to suit the required temperature. The flame burners permit a very groat variation of power, but this variation, in any case, can be achieved only by frequent action on the part of the user.

In these circumstances, the apparatus most often functions at excessive power in relation to actual requirements, and this constitutes wastage of energy.

The purpose of the present invention is to remedy this drawback.

According to the present invention, the movable heater incorporating a gas bottle and consisting of a housing for concealing the bottle and of a heating unit is characterized in that a thermostatic valve is fitted in the supply circuit of the burner so as to enable the heating power to be regulated on an "all or little" or an "all or nothing" basis.

Thus, regulation of the heating operation can be achieved automatically after preselection of a predetermined temperature.

Other features and advantages of the invention will appear during the course of the following description of particular forms of construction, which are provided simply by way of example and are illustrated in the drawings in which: Figure 1 is a view of a heater in accordance with the invention; Figure 2 is a diagram of the supply circuit; Figure 3 is a view of a unit comprising a safety valve and a thermostat; Figures 4, 5, 6 and 7 are diagrams showing the mode of operation of the unit comprising a thermostat and a device for ensuring that the atmosphere is safe; Figure 8 is a diagram of an arrangement in accordance with the invention which permits operation on an all or nothing basis; and Figure 9 is a sectional view of the thermostat.

From Fig. 1 it can be seen that, in the known manner, the heater consists of a housing 1 for concealing the bottle, which housing is mounted on rollers 2 resting on the ground and contains a bottle shown in broken lines in the Figure, a partition 3, likewise shown in broken lines, separating the bottle from the heating part which, in the present case, is formed by a burner 4, as will be described in greater detail hereinafter, said burner 4 being connected to the bottle by a pipe. This pipe comprises a flexible portion 5 consisting of a rubber tube, for example, connected to a safety valve-cock 6, which is connected to a thermostat indicated as a whole by the reference 7, the outlet of said thermostat being connected to the burner through a rigid pipe 8, part of which is illustrated in the brokenaway portion of Fig. 1.Provided in the upper wall of the housing 1 is a flap 9 which, in particular, enables the thermostat to be regulated.

Fig. 2 illustrates in greater detail the supply circuit proper, and this Figure again shows the previously mentioned components such as the burner 4, the safety valve 6 and the thermostat 7. The safety valve 6 is connected to a pipe 5 by way of an inlet port 10 and it has two outlet ports 11 and 12, which are connected respectively to a thermostat unit 7 and to the pilot burner 1 3. The valve 6 comprises a general safety flap 14 which can block the opening 1 5 for the passage of gas, said valve 6 also comprising a secondary flap 1 6 adapted to block the passage 1 7 for the gas designed to supply the burner 4.The flaps 14 and 1 6 are controlled by a push-button 18, which is urged by a return spring 1 9 towards its upper position, which is that illustrated in the Figure.

The pipe 8a is connected to the inlet port 20 of the thermostatic valve 21, the outlet of which is connected to the pipe 8b which carries the gas towards the burner 4. The valve 21 is controlled by the thermostat proper 22.

Located in the flame of the pilot burner 1 3 is a thermocouple element 23 which, by way of leads 24, renders it possible to act on the magnetic head 25 for which keeps open the gas-supply passage. As mentioned previously, this safety means is well-known and does not form paRt of the invention. It will simply be mentioned that when the flame 1 3 of the pilot burner goes out, the thermocouple 23 cools down and the signal is transmitted to the magnetic head 25 which releases the main flap 14 so as to block the gas passage 1 5.

The heater can then be brought into operation only by acting on the push-button 1 8 which moves the flap 14 into the bottom position and thus permits gas to pass towards the pilot burner, so that while the push-button is depressed, supply to the burner is interrupted by engagement of the flap 1 6 with its seat.

Fig. 3 illustrates a practical embodiment of a unit comprising a safety valve and a thermostat. The flexible gas tube is connected to the port 10 so that the gas is able to penetrate into the interior of the valve 6. When the valve 6 is partially opened, the gas passes out of this valve through the port 1 2 and is directed towards the pilot burner. When the valve 6 is completely opened, the gas moves out of it by way of the ports 11 and 1 2 so that the pilot burner and the main burner are supplied with gas simultaneously.According to the invention, the supply of gas to the pipe 8b which is connected to the main burner is controlled by a thermostat 22 which preferably comprises an air-tight chamber containing an expansible fluid acting on a flap, regulation being adjusted by means of hand-wheel 26, which is graduated to correspond to the ambient temperature that is to be established. To achieve this, an expansible body expands or contracts and thus permits an even heat to be obtained.

The gas is caused to circulate by priming the safety device of the valve 6, this priming action being brought about by actuating the push button 1 8 for approximately fifteen sec onds. This period of time permits the action of the safety pilot flame on the thermocouple 23 to produce an electric current which acts on the electro-magnet 25 for holding the main safety flap in the open position. Gas therefore circulates continuously towards the pilot burner. If the latter is accidentally extingu ished, the thermocouple 23 cools down and causes closure of the general safety flap which controls the supply of gas.

Figs. 4 to 7 illustrate the various positions of the valve and thermostat arrangement dur ing its operation.

In these Figures, the previously mentioned components have the same reference numer als. Fig. 4 illustrates the arrangement in the rest or safety position. The supply to the pilot burner 1 3 and to the main burner is cut off, the general safety flap 14 resting on its seat because of the action of the return spring 28.

Fig. 5 illustrates the operation of priming the safety device. This priming operation is car ried out by acting on the push-button 1 8 for several seconds. Pressure on the push-button causes translatory movement of the push button and of the control rod 29, and this causes the flap 1 6 to close and the flap 14 to open, the return spring 28 then being com pressed. The gas can then pass between the inlet port 10 and the outlet port 1 2 and it is able to supply the pilot burner 1 3 which can be lit by hand or by means of a piezo-electric lighter. The occurence of a flame at the pilot burner 1 3 causes the thermocouple 23 to heat up and, when the required temperature is reached, the flap 14 is held in its open position by the electro-magnet 25.

It is then possible to release the push button 1 8 which returns to its rest position under the action of the spring 1 9 and in so doing moves the control rod 29 which lifts the flap 1 6 from its seat, this position being illustrated in Fig. 6. The gas can then flow not' only towards the pilot burner by way of the port 12, but also towards the main burner by way of the port 11, the flame of the burner 1 3 thus causing the burner 4 to be lit.

As shown in Fig. 7 and in accordance with the invention, a thermostat is fitted on the port 11. This thermostat is designated as a whole by the numeral 22 and comprises a thermostatic element 30 which contracts or dilates in dependence upon the ambient tem perature and which acts on the flap 31 by way of a slide rod 32 whereby a relatively large supply of gas is provided as a function, on the one hand, of the regulation carried out by the user and, on the other hand, of the ambient temperature. The flap 31 may also be actuated by a sensor which picks up the temperature from a distance.

According to the present invention, there is thus provided'a heater, the heating programme of which is automatically regulated as a function of the ambient temperature, and this eliminates the need for any intervention on the part of the user during the operation of the heater.

The embodiment that has been described enables the heating programme to be regulated on an "all or little" basis. In other words, the flap 31 allows a large or small quantity of gas to pass through. In a case in which it is not possible to cause the burners to operate satisfactorily on a greatly reduced supply of gas, the "all or little" programme can be replaced by an "all or nothing" programme, that is to say, regulation of the heating is based on the combustion time and not on the quantity of gas burned. This regulation can be achieved by a means such as that illustrated in Fig. 8, in which the previously used reference numerals designate the same elements.

Connected between the safety valve 6 and the themostatic valve 7 is a differential-pressure valve 33 attached, on the one hand, to the pipe 8a and, on the other hand, to two outlet pipes 35 and 36 which carry the gas to the burner 4 and to an excess-gas burner 39 respectively. The differential-pressure valve comprises a diaphragm 34 solidly connected to a flap 40 which, when the diaphragm is deformed under the action of a difference in pressure between the upper and lower compartments that it defines, is adapted to close off the pipe 35. The flap 40 is primed, for example, by a spring, not illustrated. A hole 41 pierced in the diaphragm 34 permits leaked gas to pass into the upper chamber and, when the flap 38 is open, carries gas to the gas burner 39.It will be seen that the flap 38 is a solid flap which, in contrast to what happens in the previously described embodiments, completely closes off the pipe 37 when it rests on its seat. The mode of operation of this arrangement is as follows: when the safety valve and the thermostatic flap are opened, the gas arrives at burner 4 by the route 8a-35. When the flap 38 closes, then in view of the regulation achieved by means of the knurled wheel 28 and taking into account the ambiant temperature, pressure increases in the upper chamber, and the flap 40 closes the pipe 35, so that supply to the burner is interrupted. When the flap 38 opens again, the gas contained in the upper chamber flows towards the excess-gas burner, the diaphragm returns to its position of equilibrium, so that the gas-supply passage by way of the pipe 35 is opened.The main burner is relit by the pilot burner 1 3.

Fig 9 illustrates, in section, a thermostatic valve 7 of the type used in the "all or little" regulating system.

Previously mentioned elements will be seen again in this Figure. Connected at the outlet of the safety valve 6 is the thermostatic valve 7, so that the pipe 8a communicates with the pipe 8b when the flap 31 is lifted from its seat 44. The flap 31 is controlled by a piston 43 primed by a spring 42 solidly connected to a chamber 45 immersed in a fluid 46 such that its expansion is transmitted to the bellows 30 and acts on the piston 43 which bears against the flap 31 which it presses onto its seat 44 by compressing a return spring 47.

It can be seen from this Figure that turning of the knurled wheel 26 enables the return tension of the spring 47 to be regulated and therefore permits the displacement of the piston 43 under the action of the expansion of the fluid 46.

Claims (8)

1. A movable gas-heater incorporating a gas bottle in a housing and not discharging the gases of combustion into the atmosphere, which heater comprises a burner or a catalytic panel connected to said bottle by way of a pipe supplying the burner or the catalytic panel, in which pipe is fitted a safety valve piloted by a thermocouple sensitive to the flame of a pilot burner providing safety against the atmosphere, so that extinction of the pilot flame causes interruption of the supply of gas to the burner or the catalytic panel, characterized in that the supply to the burner or to the catalytic panel is also controlled from a thermostat, a supply pipe for the pilot burner being connected to the safety valve downstream of a general safety flap of this latter valve, so that extinction of the pilot flame also causes its supply to be interrupted, and in that the thermostat controls the supply to the burner or to the catalytic panel by way of a thermostatic regulating valve.

2. A gas-heater according to claim 1, characterized in that the thermostatic regulating valve comprises a regulating flap containing an orifice providing reduced flow, the position of this regulating flap permitting variation in the amount of gas supplied to the burner or to the catalytic panel.

3. A gas-heater according to claim 1, characterized in that the themostatic regulating valve comprises a solid regulating flap so as to block the passage of gas completely in the closed position.

4. A gas-heater according to claim 3, characterized in that a differential pressure valve is fitted in the pipe for supplying the burner or the catalytic panel, between the safety valve and the burner or the catalytic panel, the thermostatic regulating valve being fitted in a branch pipe terminating at the burner or at the catalytic panel by way of an excess-gas burner, the position of the regulating flap of the thermostatic regulating valve causing the burner or the catalytic panel to be supplied with gas or interrupting this supply by way of the differential pressure valve.

5. A gas-heater according to claim 4, characterized in that the differential pressure valve is constituted by an enclosure divided into two chambers by a flexible diaphragm in which an orifice is formed, an inlet port, connected to the safety valve, terminating in a first chamber into which also extends the end of the pipe for feeding the burner or the: catalytic panel, whereas an outlet port, tèrmi- nating at a second chamber, communicates with an inlet of the thermostatic regulating valve, the outlet of which is connected to the excess-gas burner.

6. A gas-heater according to claim 5, characterized in that the flexible diaphragm carries a flap which blocks that end of the supply pipe of the burner or catalytic panel that opens into the first chamber of-the differential pressure valve when the pressure in the second chamber of this latter chamber is higher than the pressure in the first chamber.

7. A gas-heater according to any one of claims 1 to 6, characterized in that the safety valve is provided with a means for opening the general safety flap and for supplying the pilot burner and then the main burner or catalytic panel on a timed basis.

8. A gas heater substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.