EP0077368B1

EP0077368B1 - An apparatus for space heating

Info

Publication number: EP0077368B1
Application number: EP19820901374
Authority: EP
Inventors: Antonius Petrus Dekkers
Original assignee: Kongskilde Koncernselskab AS
Current assignee: Kongskilde Koncernselskab AS
Priority date: 1981-04-27
Filing date: 1982-04-26
Publication date: 1986-02-19
Also published as: WO1982003905A1; DE3269132D1; EP0077368A1; NL8102065A

Abstract

An apparatus for space heating, in particular suitable for burning all kinds of liquid hydrocarbons, moreover for heavy liquid fuels of high viscosity, said apparatus is mainly comprising a housing (4) enveloping a combustion chamber (1), having an inlet opening (2) for combustion air, provided with a first blower (9) and an outlet opening (3) for the flue gases, a second blower (16) for forced air transport around the combustion chamber in the housing, a burner pot (4) located at the bottom of the combustion chamber (1) and a fuel pump (18), supplying a fuel tube (21) leading from a fuel tank (17) into said burner pot (4), wherein a presssure chamber (6) for the combustion air communicating with said air inlet opening (2) is arranged around said burner pot (4), whereas in the wall of the burner pot series of relatively small holes (10) communicating with said pressure chamber (6) are arranged over eachother, a partly open baffle plate (11) being arranged in the burner pot (4) in between the series of holes (10) and an electric control circuit to control the different blowers and fuel pump.

Description

The invention relates to an apparatus for space heating, in particular suitable burning all kinds of liquid hydrocarbons, and moreover suitable for heavy liquid fuels of high - viscosity, said apparatus mainly comprising a combustion chamber having an inlet opening for air and a flue gass outlet opening, a burner pot vertically arranged at the bottom of the combustion chamber, a fuel supply tube leading from a fuel tank into said burner pot, a pressure chamber for the combustion air communicating with said air inlet opening and gastight arranged around said burner pot, whereas in the wall of said burner pot series of relatively small holes communicating with said pressure chamber are arranged over each other, a partly open, baffle arranged in the burner pot and in between said series of holes in order to obtain combustion regions above each other, and a blower in the air supply channel to the pressure chamber, whereas the combustion chamber is enveloped by a housing provided with means for forced air transport.
An apparatus of the kind set forth is disclosed in US―A―3 051 229, wherein the burner pot provides an intermingling of combustion air and gas.
However, the object of the invention is to ameliorate such a device in order to be able to burn all kinds of heavy oils or other liquid fuels, for instance waste-oil or residual-oil, whereas the emission of noxious flue gases are limited to a minimum. The apparatus according to the invention is distinguished in that the baffle rim is in intimate contact with the inner wall of the burner pot, the diameter of the holes above said baffle is smaller than that of the holes below said baffle whereas said baffle rim has a series of openings.
So the combustion air can be supplied to the burner pot under pressure, whereas the relatively small holes are acting like air jets, providing an intensive mixture with the vaporising liquid fuel.
In GB-A-1 109 230 is disclosed a heating apparatus, wherein a burner pot is arranged with an air supplying chamber which is not fed by a blower. Together with the arrangement of series of holes in the wall of the burning pot in combination with a baffle plate it will be not possible to vaporise and burn heavy liquids as is the object of the invention.
In order to lower the flue gas temperature in the outlet opening the apparatus is provided with a heat exchanger beside the combustion chamber within the housing, whereas said means for forced air transport are located at the side of said exchanger remote from said combustion chamber. For a longer flue-gas way so ameliorating the heat transfer to the outside the apparatus is provided with a standing deflecting member arranged in the combustion chamber in front of of through-let to said exchanger.
In the event the apparatus is provided with a fuel tank arranged within the housing, the invention further proposes to connect the fuel pump at the lower end of a riser of the fuel tube in the tank, so retaining the tank clear from the fuel supply system of the apparatus, the tank is therefore easily dismountable and to be cleaned, whereas a branch tube returning to the tank is connected to that part of the fuel tube following upon the riser in order to prevent a syphoning action. Moreover there is obtained the advantage, in that when the fuel tube is jammed near the burner pot the fuel pump will feed the fuel back to the tank.
In the event the apparatus is provided with an electric control circuit to control the different blowers and fuel pump, than the pump is, according to the invention, powered through a flame watching device and/or a maximum thermostat. This gives the advantage that should the flame drop down or should the temperature raise to high respectively, the pump is automatically switched off.
In a further embodiment the blower for the forced air transport in the housing is powered through a limit thermostat the reset point will be at a lower temperature than that of the maximum thermostat. So when the fuel pump falls out the forced air transport around the combustion chamber is maintained, in order to cool off the chamber fast.
According to a further feature of the invention the apparatus may be provided with a removable bottom-part of the combustion chamber in order to easily taking out and cleaning the burner-pan wherein residuals may be collected.
The invention will be further elucidated in the detailed description of two embodiments.
In the drawing is:

Fig. 1 a perspective view of an apparatus according to the invention, parts of the housing are broken away,
Fig. 2 a perspective view of the burner pot used in the apparatus of fig. 1,
Fig. 3 and 4 each a side view of the apparatus provided with a pivotable and removable fuel supply tank,
Fig. 5 a side view of a second embodiment of the apparatus,
Fig. 6 a cross section along the line VI-VI in fig. 5,
Fig. 7 a schematic view of the electric control circuit used in the apparatus according to fig. 1.

In figure 1 the reference numeral 1 is related to the combustion chamber, which is of a substantially cylindrical form, an inlet opening 2 for the combustion air, running into the cylinder wall, and an outlet opening 3 for the flue gases.
At the bottom of the combustion chamber 1 a burner pot 4 is located, the outer wall 5 of which is placed at such a distance to the inner wall of the combustion chamber 1, that an annular pressure chamber 6 around the burner pot 4 is formed. The pressure chamber 6 is limited at the bottom and top side by flanges 7, 8. The inlet opening 2 conmunicates with the pressure chamber 6, whereas in front of the inlet opening 2 a blower 9 is placed.
The wall 5 of the burner pot 4, which is shown in detail in figure 2, is provided with series of holes 10, arranged over each other, which holes having a small diameter related to the dimensions of the burner pot 4. In the burner pot a baffle plate 11 is arranged, which baffle plate is provided with a central through-let opening 12, and a series of apertures 13 around said central opening 12. The height of the baffle plate 11 in the burner pot 4 is such that only the two lower series of holes 10 are located below the baffle plate 11. The diameter of the holes in the two series above the baffle plate is smaller than that of the holes in the lower series.
The whole combustion chamber is enveloped in a housing 14, which housing has a rectangular form, whilst it is provided with a screen 15 in the two opposite side walls and backwall. Underneath the top wall a second blower 16 is arranged, which will cauase a forced air transport from the top downwards along the combustion chamber 1 onto the side walls, which transported air is heated by the wall of the combustion chamber.
In the housing 14 is provided a spacing at the front side, in which a tank 17 is taken up, which tank is forwardly turnable on studs 27, see also fig. 3. The top side of the rectangular tank 17 is fully open, so the fuel can easily be poured in the tank.
In the tank is located a pump 18, for instance a gear pump, which pump sucks the fuel through a strainer 19, covered at the top side and forces the fuel through a riser 20 unto the fuel supply tube 21. The fuel supply tube leads to the bottom of the burner pot 5.
In the fuel supply tube is taken up a branch tube 22, which leads to the top of the tank 17. The pump 18 is driven through a driving shaft 23 and a gearing 24 by a motor 25.
The whole fuel-supply-system, comprising a motor 25, the pump 18 and the tubes is completely free from the fuel tank 17, in order to be able to remove the fuel tank 17 out of the housing 14, for instance to pulling out the studs 27. According the manner showed in figure 4, the tank may be lowered and removed, whereupon the tank may be cleaned easily. The mounting of the tank will take place in a reverse way.
A flame-guarding device 26 is taken up in the electric control system for the various blowers and pump, what will be further elucidated with reference to the electrical diagram of figure 7. The flame-guarding device 26 is directed to the burner pot 4 and will switch off the fuel supply as soon as the flame drops down.
The combustion will be processed as follows:

On turning the pump 18 the fuel will be forced into the burner pot through the tube 21. The fuel vaporises there and combustion air is led from the pressure chamber 6 through the series of holes 10 into the burner pot 4 by means of the blower 9. After an intensive mixing there will be formed a burnable mixture, in the first burner region below the baffle plate 11, whereupon the burned and partly unburned flue gases are coming through the central opening 12 and holes 13 respectively in the second burning region of the burner pot 4. Here an additional mixing will take place by means of the jetted air streams through the upper series of holes 10, whereas the burning will further take place in the combustion chamber, whereupon the flue gases will disappear, through the opening 3 out of the apparatus.

The blower 16 causes a forced air transport around the combustion chamber 1, whereby the ambient air can be heated and blown through the side screens 15 into the space.
Making reference to fig. 5 and 6 the embodiment shown therein is substantially similar to the embodiment described above, and the same parts are quoted with the same reference numbers. The said second embodiment is provided with a heat exchanger 40 extending in parallel relationship to and beside the combustion chamber 1 within the housing 14. The blower 16 for forced air transport through the housing 14 is located here at the side of the exchanger 40 remote from the combustion chamber 1, so forced ambient air between the lids 41 of the exchanger unto the combustion chamber 1, see arrow P3. The limit thermostat controlling said blower 16 is taken up in the flue gas collector 42 downstreams the lids. The exchanger is connected with the combustion chamber 1 by a throughlet 43 near the burner pot 4. The through- let 43 is covered by a deflecting plate 44 rising into the combustion chamber forcing the flue gases to flow up and downwards in said chamber.
The bottom part 45 of the combustion chamber is supported on a rocking arm 46, pivotable at 47, whereas the free end of said arm 46 carries a foot- pedal 48, protruding outside the front side of the housing. The pivot 47 is arranged on a slide structure 49 allowing to bring out the bottom part 45 by raising the foot pedal, lowering said bottom part and pulling out the slide structure. The burner pan 50 so supported upon the bottom part can be easily removed and cleaned so.
The apparatus is electrically protected by means of the diagram according to figure 7.
In the diagram the same parts of the apparatus are quoted with the same reference numerals.
The motor of the blower 16 is powered by the main line through a limit theromostat 30, which switches on the power as soon as the temperature is raisen sufficiently enough. The motor of the blower 9 for the combustion air is also directly connected to the main line.
The main switch 31 leads to a switchblock 32, in which the flame-guarding device 26 is taken up. Through said switchblock 32 the motor 25 for the fuel pump 18 is powered. In the supply line 33 of the motor 23 is embodied a maximum thermostat 34, which will switch off the power for the motor 25 at a presetted maximum temperature. Overheating of the combustion chamber 1 is prevented so. The control of the motor 25 will further take place through an electronic circuit 35, substantially comprising a diode and a triode system 36, which is controlled by variable resistors 37, such that the rotational speed of the motor 25 is continuously variable. In a manner known in the art, the various resistors and capacitors in the electronic control circuit 25 ensure its correct working.
The reference number 38 is related to a pilot lamp of the motor 25, whilst also here a pair of capacitors ensure an inference free working. The safety of the apparatus is ensured by setting the resistances such that at a certain temperature the pump motor 25 is switched off earlier than the motor of the blower 16. So the fuel supply will be stopped earlier, before the motor of the blower 16 is switched off, whilst the motor of the blower 9 is permanently in operation.
As soon as the flame drops down, the supply of the fuel will be stopped by means of the flame-guarding device 26, which will stop the motor 25. Finally it is to be mentioned that when the tube 21 near the burner pot 4 is obstructed the supplied fuel will flow back to the tank through the return tube 22. Further, when the motor 25 is stopped, and so the fuel supply is stopped, a syphon action is prevented owing to the return tube.

Claims

1. An apparatus for space heating, in particular suitable for burning all kinds of liquid hydrocarbons, and moreover suitable for heavy liquid fuels of high viscosity, said apparatus mainly comprising a combustion chamber (1) having an inlet opening for air (2) and a flue gass outlet opening (3), a burner pot (4) vertically arranged at the bottom of the combustion chamber (1), a a fuel supply tube (21) leading from a fuel tank (17) into said burner pot (4), a pressure chamber (6) for the combustion air communicating with said air inlet opening (2) and gastight arranged around said burner pot (4), whereas in the all of said burner pot (4) series of relatively small holes (10) communicating with said pressure chamber (6) are arranged over eachother, a partly open, baffle (11) arranged in the burner pot (4) and in between said series of holes (10) in order to obtain combustion regions above eachother, and a blower (9) in the air supply channel to the pressure chamber (6), whereas the combustion chamber (1) is enveloped by a housing (14) provided with means (16) for forced air transport characterized in that the baffle rim is in intimate contact with the inner wall of the burner pot (4), the diameter of the holes above said baffle (11) is smaller than that of the holes below said baffle whereas said baffle rim has a series of openings (13).

2. An apparatus according to claim 1, characterized in that an heat exchanger (40) is arranged beside the combustion chamber (1), within the housing (14), and in that said means for forced air transport (16) are located at the side of said exchanger (40) remote from said combustion chamber (1).

3. An apparatus according to claims 1 and 2, characterized in that in the combustion chamber (1) a standing deflecting member (44) is arranged in front of the through-let to said exchanger (40).

4. An apparatus according to claims 5 and 6 provided with a fuel tank (17) taken up in the housing (14), characterized in that a fuel pump (18) feeding the fuel supply tube (21) is arranged at the lower end of a riser (23) of said fuel tube (21) and in the tank, wherein a branch tube (22) leading to the tank is connected to a part of the fuel tube following the riser (23).

5. An apparatus according to one of the preceding claims, provided with an electric control circuit for controlling the various blowers and fuel pump, characterized in that the pump is powered through a flame-guarding device (26) and/or a maximum thermostat (34).

6. An apparatus according to claim 5, characterized in that the blower (16) for forced air transport in the housing is powered through a limit thermostat (30) having a switch point at a lower temperature than that of the maximum thermostat (34).

7. An apparatus according to claim 5 and 6, characterized in that the rotational speed of the pump (18) and whereby the fuel supply is controlled by means of an electronic continuously variable circuit (35-37).

8. An apparatus according to claim 6 and 7, characterized in that said limit thermostat (30) is located in the flue gas channel downstreams the exchanger (40).

9. An apparatus according to claim 1-8, characterized in that the bottom part (45) of the combustion chamber (1) is removable.

10. An apparatus according to claim 9, characterized in that said bottom part is supported on an up and down movable member (46―49) removable from said housing.

11. An apparatus according to claim 9 and 10, characterized in that said member (46―49) is arranged on a slide structure forming part of the housing (14).