CA2586499A1

CA2586499A1 - Liquid fuel burner

Info

Publication number: CA2586499A1
Application number: CA002586499A
Authority: CA
Inventors: Paul Eksteen; Gary Kenneth Diamond
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-11-04
Filing date: 2005-11-04
Publication date: 2006-05-11
Also published as: EP1815186A1; MX2007005440A; JP2008519240A; WO2006048741A1; WO2006048741B1; IL183011A0; AP2007004000A0; KR20070089684A; CN101091091A; ZA200604614B

Abstract

The invention provides a liquid fuel burner (110) comprising a burner head (114), a liquid fuel reservoir (116) for containing a liquid fuel, and a pump (118) for pumping the liquid fuel from the reservoir (116) to the burner head (114). The pump (118) includes a cylinder (140), and a piston (142) which is displaceable relative to the cylinder (140) so that liquid fuel is drawn into the cylinder (140) when the piston and cylinder are displaced in a first direction relative to one another, and the liquid fuel is pumped out of the cylinder (140) when the piston and cylinder are displaced in a second, opposite direction relative to one another. The pump (118) also includes an inlet valve (144) for allowing liquid fuel to be drawn into the cylinder (140) from the reservoir (116), an outlet valve (146) for allowing liquid fuel to be pumped out of the cylinder (140) to the burner head (114), and a displaceable mass which due to its weight applies sufficient force to cause displacement of the piston (142) relative to the cylinder (140) in the second direction, thereby to pump liquid fuel out of the cylinder (140) to the burner head (114).

Description

LIQUID FUEL BURNER

BACKGROUND OF THE INVENTION

THIS invention relates to burners, and more specifically to a liquid fuel burner which may be used in devices such as stoves, geysers, heaters and the like. The invention also relates to a device for delivering liquid fuel to a burner head of a liquid fuel burner.

Various different types of liquid fuel burners are known. In some of these devices, capillary action causes liquid fuel to be drawn onto a wick from where it is burned, while in other applications air pressure is applied to a liquid fuel to displace the fuel towards a burner head.

Although devices such as liquid fuel stoves often are preferable to electric devices because either electricity is not easily accessible or electric devices are relatively expensive to operate, many of the known liquid fuel burners are relatively unsafe and/or are not very efficient.

It is an object of the present invention to provide an alternative liquid fuel burner which is generally safe and efficient.

It is a further object of the invention to provide a liquid fuel burner which is relatively easy to use.

CONFIRMATION COPY

SUMMARY OF THE INVENTION

According to the invention there is provided a liquid fuel burner comprising:
a burner head;
a liquid fuel reservoir for containing a liquid fuel; and a pump for pumping the liquid fuel from the reservoir to the burner head, the pump including:
a cylinder;
a piston which is displaceable relative to the cylinder so that liquid fuel is drawn into the cylinder when the piston and cylinder are displaced in a first direction relative to one another, and the liquid fuel is pumped out of the cylinder when the piston and cylinder are displaced in a second, opposite direction relative to one another;
an inlet valve for allowing liquid fuel to be drawn into the cylinder from the reservoir;
an outlet valve for allowing liquid fuel to be pumped out of the cylinder to the burner head; and a displaceable mass which due to its weight applies sufficient force to cause displacement of the piston relative to the cylinder in the second direction, thereby to pump liquid fuel out of the cylinder to the burner head.

Preferably, the inlet valve is a one-way valve for allowing liquid fuel into the cylinder, and the outlet valve is a one-way valve for allowing liquid fuel out of the cylinder.

In one embodiment of the invention, the piston is displaceable within the cylinder towards a raised condition for drawing liquid fuel into the cylinder and towards a lowered condition for pumping liquid fuel out of the cylinder.
In this embodiment, the piston may be attached to the burner head via a piston tube, and the piston may define an opening for allowing fluid communication between the cylinder and the piston tube.

The rate of displacement of the piston relative to the cylinder, and hence the rate at which liquid fuel is pumped out of the cylinder, may be regulated by a control mechanism which applies a variable resistance to the displacement of the piston relative to the cylinder.

The control mechanism may include an adjustment screw for applying a variable resistance to the displacement of the piston tube.

In one form of the invention, the piston tube is arranged to pass through a bush, and the adjustment screw is threaded into the bush so as to be engagable with the piston tube.

The cylinder may be located within the liquid fuel reservoir, in which case, the cylinder may communicate with the reservoir via the inlet valve and possibly a filter.

In one embodiment of the invention, the inlet valve and the outlet valve each include a valve closure which, in ordinary operation, is movable relative to a valve seat between an open position in which the valve closure is spaced from the valve seat to allow for one-way flow of liquid fuel through the valve, and a closed position in which the valve closure engages the valve seat to prevent liquid fuel flow through the valve. In this embodiment, for each valve, the valve closure may be displaceable relative to the valve seat when the liquid fuel burner is tipped to allow liquid fuel to flow through the valve in a direction opposite to the one-way, ordinary operation flow of liquid fuel.

In another embodiment of the invention, the piston is fixed relative to a frame of the burner and the cylinder is displaceable relative to the burner frame. In this embodiment, the displaceable mass may form part of, or be attached to, the cylinder, and the piston may include ports for allowing the liquid fuel to be drawn into the cylinder or pumped out of the cylinder.

The burner may include a frame formed from tubular sections, in which case the reservoir may be formed by at least a portion of the tubular sections.

In one arrangement, the frame is curved along side portions thereof and the burner includes a stabilising mass for self-righting the frame if the burner is tipped to one side.

The stabilising mass may be the displaceable mass.

The burner may also include a regulator in the form of a valve for regulating the delivery of liquid fuel to the burner head and hence the intensity of combustion at the burner head.

In one embodiment of the invention, the burner includes a duel shut-off device for preventing the flow of liquid fuel to the burner head when the pressure at the burner head drops below a predetermined magnitude, for example if the flame is extinguished, and for preventing back-pressure displacement of the liquid fuel from the burner head to the cylinder when the pressure at the burner head rises above a predetermined magnitude.
The invention extends to a pump for pumping liquid fuel from a reservoir to a burner head of a liquid fuel burner, the pump including:
a cylinder;
a piston which is displaceable relative to the cylinder so that liquid fuel is drawn into the cylinder when the piston and cylinder are displaced in a first direction relative to one another, and the liquid fuel is pumped out of the cylinder when the piston and cylinder are displaced in a second, opposite direction relative to one another;
an inlet valve for allowing liquid fuel to be drawn into the cylinder from the reservoir;
an outlet valve for allowing liquid fuel to be pumped out of the cylinder to the burner head; and a displaceable mass which due to its weight applies sufficient force to cause displacement of the piston relative to the cylinder in the second direction, thereby to pump liquid fuel out of the cylinder to the burner head.

The inlet valve and the outlet valve may each comprise a one-way valve.
BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a perspective view of a liquid fuel burner according to one embodiment of the present invention;

Figure 2 shows a partial cross-sectional view of the burner illustrated in Figure 1;

Figure 3 shows a perspective view of a liquid fuel burner according to another embodiment of the invention;
Figure 4 shows a cross-sectional view of the burner of Figure 3 with the frame omitted for clarity and with a burner head in a lowered condition;

Figures 5 and 6 show cross-sectional views similar to that of Figure 4 with the burner head in a raised condition and in a tipped condition, respectively;

Figure 7 illustrates a cross-sectional view of a portion of a liquid fuel burner according to yet another embodiment of the invention with a burner head in a lowered condition; and Figures 8 and 9 illustrate cross-sectional views similar to that of Figure 7 with the burner head in a raised condition and in a tipped condition, respectively.

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 and 2 of the accompanying drawings illustrate a liquid fuel burner according to one embodiment of the present invention. In this embodiment, the liquid fuel burner is in the form of a paraffin stove 10 which includes a frame 12, a burner head 14 mounted to the frame, a reservoir 16 for containing paraffin, and a pump 18 for pumping the paraffin from the reservoir 16 to the burner head 14.

As representatively illustrated in Figures 1 and 2, the frame 12 may include four legs 20 which are joined together at a base 22 of the frame. The legs 20 may be formed from tubular material, such as, for example, tubular steel sections, so that the reservoir 16 is formed within the hollow legs 20.
Removable caps 24 may be provided for accessing the reservoir 16. As can be seen, the operatively upper ends of the legs 20 may be connected to a cooking vessel support 26 for supporting pots, pans, and the like (not illustrated). The support 26 typically comprises an outer ring 28, an inner ring 30, and four radial limbs 32 extending between the outer and inner rings.

With particular reference to Figure 2, the pump 18 may include a cylinder 34 and a piston 36 which are displaceable relative to one another. In this embodiment of the invention, the piston 36 is fixed to the frame 12 and the cylinder 34 is displaceable relative to the frame in the directions of the arrows A and B in Figure 2. The piston 36 is seen to include a first port 38 and an inlet valve 40 for allowing paraffin in the reservoir '16 to be drawn into the cylinder 34, and a second port 42 and an outlet valve 44 for allowing the paraffin to be pumped out of the cylinder 34 to the burner head 14. A fuel line 45 extends from the outlet valve 44 to the burner head 14, and a regulator in the form of a valve 46 on the fuel line 45 allows for the adjustment of the paraffin supply to the burner head 14 and hence the intensity of the flame at the burner head.

The pump 18 includes a seal in the form of an elastomeric 0-ring 48 between the cylinder 34 and the piston 36. Tlhe pump 18 also includes a mass in the form of a ring 50 which extends around the cylinder 34, as shown. The ring 50 has a weight sufficient to d isplace the cylinder 34 in the direction of the arrow B so as to pump paraffin within the cylinder 34 to the burner head 14 under pressure.

The stove 10 also includes a duel shut-off devi ce 52 for controlling the flow of paraffin to or away from the burner head 14. As representatively illustrated in Figure 2 of the drawings, the duel shut-off device 52 may include a ball 54 which is displaceable within a chamber 56 between an upper seat 58 and a lower seat 60.

In practice, the reservoir 16 is filled with paraffin by removing one of the removable caps 24 and pouring paraffin into the reservoir. The removable cap 24 is then replaced and the cylinder 34 is manually displaced in the direction of the arrow A into the position illustrated in Figure 2. As the cylinder 34 is displaced upwardly, paraffin is drawn into the cylinder through the port 38 and the inlet valve 40. With the cylinder 34 in the Figure 2 position, the regulator 46 is opened so as to allow paraffin to flow to the burner head 14. The cylinder 34 is then released and the ring 50, by virtue of its weight, applies a force to the cylinder, u rging it in the direction of the arrow B. As the cylinder 34 is displaced downwardly, it applies pressure to the paraffin within the cylinder, and the pressured paraffin is displaced towards the burner head 14 to fuel combustio n and provide heat energy at the support 26. During cooking, the regulator 46 is adjusted to provide the desired heat energy at the support 26, and once the cooking has been completed, the flame at the burner head 14 is extinguished by closing the regulator 46.

The duel shut-off device 52 which serves a safety function may be conventional in nature. For example, the device 52 may be designed so that when the cylinder 34 is displaced in the direction of the arrow B, paraffin displaces the ball 54 off the seat 60 so as to allow paraffin to flow to the burner head 14. However, if the flame is extinguished suddenly and a drop in pressure occurs at the burner head, paraffin displaces the ball 54 against the seat 58 to close the device and prevent the flow of paraffin to the burner head 14. If, on the other hand, the pressure at the burner head 14 rises above a pre-determined magnitude, the ball 54 is displaced against the seat 60 to prevent the flow of paraffin back towards the cylinder 34.

The ring 50 may be arranged to locate below the center of gravity of the stove 10 so that if the stove is accidentally tipped to one side, the weight of the ring 50 serves to automatically right the stove. Alternatively, additional weight may be provided in the piston 34 or elsewhere on the frame 12 to effect self-righting of the stove 10.

The stove may also include curved handles (not illustrated) which extend upwardly from the legs 20 to allow the stove to be carried relatively easily and to prevent the stove from tipping onto the cooking vessel support 26.

In an alternative arrangement, the stove 10 may include a paraffin reservoir which is separate from the frame 12, and/or a mechanism, such as, for example, a lever or pulley system, for raising the cylinder or the piston into an operative position.

It will be appreciated that the mass 50 which applies a force to the cylinder 34 to effect displacement of the cylinder in the direction of the arrow B may be integral with the cylinder or attached to the cylinder. Alternatively, the mass 50 may be arranged to apply a force to the cylinder via one or more pulleys, levers or the like. Furthermore, although the liquid fuel burner has been described above with reference to a piston and cylinder arrangement in which the piston 36 is fixed to the frame 12 and the cylinder 34 is displaceable relative to this frame, it will be understood that the liquid fuel burner may include a cylinder which is fixed relative the frame and a displaceable piston.

Figures 3 to 6 of the accompanying drawings illustrate another embodiment of a liquid fuel burner according to the present invention. Similarly to the previous embodiment, the liquid fuel burner is in the form of a paraffin stove 110 which includes a frame 112, a burner head 114, a reservoir 116, and a pump 118 for pumping paraffin from the reservoir 116 to the burner head 114.

The frame 112 may include four legs 120 which are joined together at lower ends by a base 122. The legs 120 may be formed from tubular material, such as, for example, tubular steel sections, with one pair of the legs 120 being joined to another pair of the legs by tubular frame members 124. The frame 112 may also include a cooking vessel support 126 for supporting pots, pans, and the like (not illustrated) adjacent the burner 114. The support 126 typically comprises an outer ring 128 and four limbs 130 which extend inwardly from the outer ring, as shown. In this embodiment of the invention, the support 126 is vertically displaceable relative to the legs 120, and includes guides 132 which engage the legs 120 during relative displacement.

With reference also to Figures 4 to 6 of the drawings, the reservoir 116 comprises a generally cylindrical container 134 which includes an opening 136 for filling the container with paraffin and a closure 138 for closing off the opening 136. The pump 118 may include a cylinder 140 which is at least partially submerged in the reservoir 116 and a piston 142 which is displaceable relative to the cylinder 140. The piston 142 carries a seal in the form of an elastomeric 0-ring (not illustrated) for sealing between the piston and the cylinder 140. As representatively illustrated in Figures 4 to 6, the pump 118 may include a one-way valve 144 for allowing paraffin within the reservoir 116 to enter the cylinder 140 and a one-way valve 146 for allowing paraffin to exit the cylinder. The one-way valve 144 may include a ball 148 which is arranged to seat on a dish 150 defining a central opening 152. Similarly, the one-way valve 146 may include a ball 154 and a dish 156 with a central opening 158. As can be seen, the cylinder 140 may communicate with the reservoir 116 via the one-way valve 144 and a filter 160. In this embodiment of the invention, the piston 142 is connected to the burner 114 by a piston tube 162 carrying the one-way valve 146, and the stove 110 includes an adjustment screw 164 for applying a variable resistance to the displacement of the piston 142 relative to the cylinder 140.
The adjustment screw 164 may be located within a bush 166 through which the piston tube 162 extends. As can be seen in Figures 4 to 6, the cylinder 140 may communicate with the piston tube 162 via a port 168 in the piston 142.

In practice, the reservoir 116 is filled with paraffin by removing the closure 138 and pouring paraffin into the reservoir. The closure 138 is then replaced and the piston 142 is manually displaced relative to the cylinder 140 into the raised condition illustrated in Figure 5. As the piston 142 is displaced upwardly along the cylinder 140, it draws the ball 148 of the valve 144 into an open condition and causes paraffin to be drawn into the cylinder 140 through the filter 160 and the one-way valve 144. In the raised condition of the piston 142, the ball 148 is seated on the dish 150 to close the valve 144. Accordingly, subsequent downward displacement of the piston 142 relative to the cylinder 140 causes paraffin within the cylinder to be ejected through the port 168 and into the piston tube 162. The piston 142, the piston tube 162 and the burner 114 are designed to have a mass which is sufficient to displace the piston 142 downwardly relative to the cylinder 140 when the adjustment screw 164 is disengaged from the piston tube. Accordingly, even without a pot or the like on the support 126, the piston 142 can slide downwardly within the cylinder 140 to eject paraffin into the piston tube 162. With a pot or the like on the support 126, the adjustment screw is adjusted, as required, to effect the desired flow of paraffin through the piston tube 162.

As the paraffin flows through the piston tube 162, it opens the one-way valve 146, and flows to the burner head 114 to fuel combustion and provide heat energy at the support 126. During cooking, the screw 164 may be adjusted to provide the desired heat energy at the support 126, and once the cooking has been completed, the flame at the burner head 114 may be extinguished by locking the piston 142 relative to the cylinder 140 with the adjustment screw 164.

In Figure 6, the burner has been tipped to one side, for example during accidental tipping of the stove 110. As can be seen, when the stove is tipped, the ball 148 of the valve 144 rolls off the opening 152 in the dish 150 allowing paraffin to feed back into the reservoir 116, thereby to prevent paraffin flow to the burner head 114 and hence extinguishing the burner head 114.

Figures 7 to 9 illustrate a stove in accordance with a further embodiment of the present invention. In this embodiment, the stove is similar to the stove 110 in all respects except for the design of one-way valves 244 and 246.
Accordingly, a full description of the stove components other than the valves 244 and 246 is not necessary for a full understanding of this embodiment of the invention. However, generally, the stove includes a reservoir 216, a cylinder 240, a piston 242, a piston tube 262, and a burner head 214 connected to the piston tube. The one-way valve 244 allows paraffin into the cylinder 240, and the one-way valve 246 allows paraffin out of the cylinder 240. Similarly to the embodiment illustrated in Figures 3 to 6, the stove includes a filter 260 between the reservoir 216 and the cylinder 240, and an adjustment screw 264 for adjusting the intensity of the combustion at the burner head 214.

With particular reference to Figure 7, the one-way valve 244 comprises a weighted valve stem 248 and a valve seat 250 for receiving the valve stem.
Similarly, the valve 246 comprises a weighted valve stem 252 and a valve seat 254. When the piston 242 is displaced relative to the cylinder 240 into the raised condition illustrated in Figure 8, the valve stem 248 is drawn away from the valve seat 250 and paraffin is drawn into the cylinder 240.
When the piston 242 is in the raised condition, the valve stem 248 is seated on the valve seat 250 to prevent paraffin from flowing back into the reservoir 216. As the piston 242 is displaced downwardly relative to the cylinder 240, paraffin is ejected through the piston into the piston tube 262, causing the one-way valve 246 to open and paraffin to flow to the burner head 214. The required intensity of combustion at the burner head 214 may be achieved by adjusting the screw 264. Similarly to the embodiment illustrated in Figures 3 to 6 of the drawings, if the stove is tipped to one side accidentally, the weighted valve stems 248 and 252 tilt off the valve seats 250 and 254 and allow paraffin to feed back into the reservoir 216.

The liquid fuel burner may be housed in a housing (not illustrated) which is designed to conceal the various components of the burner.

It should be appreciated that both embodiments of the invention illustrated in Figures 3 to 9 of the drawings could include a safety device in the form of a duel shut-off device similar to the device 52 described above with reference to Figure 2 of the drawings.

Although the invention has been described above with reference to different types of stoves, it will be appreciated that the liquid fuel burner may be used to provide heat in various other applications such as, for example, in geysers, furnaces or heaters.

Claims

1 1. A liquid fuel burner comprising:
a burner head;
a liquid fuel reservoir for containing a liquid fuel; and a pump for pumping the liquid fuel from the reservoir to the burner head under pressure, the pump including:
a cylinder;
a piston which is displaceable relative to the cylinder so that liquid fuel is drawn into the cylinder when the piston and cylinder are displaced in a first direction relative to one another, and the liquid fuel is pumped out of the cylinder when the piston and cylinder are displaced in a second, opposite direction relative to one another;
a one-way inlet valve for allowing liquid fuel to be drawn into the cylinder from the reservoir;
a one-way outlet valve for allowing liquid fuel to be pumped out of the cylinder to the burner head;
a displaceable mass which due to its weight applies sufficient force to cause displacement of the piston relative to the cylinder in the second direction, thereby to pump liquid fuel out of the cylinder to the burner head under pressure; and a control mechanism for applying a variable resistance to the displacement of the piston relative to the cylinder, thereby to allow for the adjustment of the supply of pressured liquid fuel to the burner head.

2. A liquid fuel burner according to claim 1, wherein the piston is displaceable within the cylinder towards a raised condition for drawing liquid fuel into the cylinder and towards a lowered condition for pumping liquid fuel out of the cylinder.

3. A liquid fuel burner according to claim 2, wherein the piston is attached to the burner head via a piston tube, and the piston defines an opening for allowing fluid communication between the cylinder and the piston tube.

4. A liquid fuel burner according to claim 3, wherein the control mechanism includes an adjustment screw for applying a variable resistance to the displacement of the piston tube.

5. A liquid fuel burner according to claim 4, wherein the piston tube is arranged to pass through a bush, and the adjustment screw is threaded into the bush so as to be engagable with the piston tube.

6. A liquid fuel burner according to any one of the preceding claims, wherein the cylinder is located within the liquid fuel reservoir.

7. A liquid fuel burner according to claim 6, wherein the cylinder communicates with the reservoir via the inlet valve and a filter.

8. A liquid fuel burner according to any one of the preceding claims, wherein the inlet valve and the outlet valve each include a valve closure which, in ordinary operation, is movable relative to a valve seat between an open position in which the valve closure is spaced from the valve seat to allow for one-way flow of liquid fuel through the valve, and a closed position in which the valve closure engages the valve seat to prevent liquid fuel flow through the valve.

9. A liquid fuel burner according to claim 8, wherein, for each valve, the valve closure is displaceable relative to the valve seat when the liquid fuel burner is tipped to allow liquid fuel to flow through the valve in a direction opposite to the one-way, ordinary operation flow of liquid fuel.

10. A liquid fuel burner according to claim 1, wherein the piston is fixed relative to a frame of the burner and the cylinder is displaceable relative to the burner frame.

11. A liquid fuel burner according to claim 10, wherein the displaceable mass forms part of, or is attached to, the cylinder, and the piston includes ports for allowing the liquid fuel to be drawn into the cylinder or pumped out of the cylinder.

12. A liquid fuel burner according to either claim 10 or claim 11, wherein the burner includes a frame formed from tubular sections, and the reservoir is formed by at least a portion of the tubular sections.

13. A liquid fuel burner according to claim 12, wherein the frame is curved along side portions thereof and the burner includes a stabilising mass for self-righting the frame if the burner is tipped to one side.

14. A liquid fuel burner according to claim 13, wherein the stabilising mass is the displaceable mass.

15. A liquid fuel burner according to any one of claims 10 to 14, wherein the control mechanism comprises a valve for controlling the delivery of liquid fuel to the burner head and hence the intensity of combustion at the burner head.

16. A liquid fuel burner according to any one of the preceding claims, wherein the burner includes a duel shut-off device for preventing the flow of liquid fuel to the burner head when the pressure at the burner head drops below a predetermined magnitude, and for preventing back-pressure displacement of the liquid fuel from the burner head to the cylinder when the pressure at the burner head rises above a predetermined magnitude.

17. A pump for pumping liquid fuel from a reservoir to a burner head of a liquid fuel burner, the pump including:
a cylinder;
a piston which is displaceable relative to the cylinder so that liquid fuel is drawn into the cylinder when the piston and cylinder are displaced in a first direction relative to one another, and the liquid fuel is pumped out of the cylinder when the piston and cylinder are displaced in a second, opposite direction relative to one another;

a one-way inlet valve for allowing liquid fuel to be drawn into the cylinder from the reservoir;
a one-way outlet valve for allowing liquid fuel to be pumped out of the cylinder to the burner head;
a displaceable mass which due to its weight applies sufficient force to cause displacement of the piston relative to the cylinder in the second direction, thereby to pump liquid fuel out of the cylinder to the burner head under pressure; and a control mechanism for applying a variable resistance to the displacement of the piston relative to the cylinder, thereby to allow for the adjustment of the supply of pressured liquid fuel to the burner head.