WO2013178198A1

WO2013178198A1 - Downdraft vertical pellet burning equipment

Info

Publication number: WO2013178198A1
Application number: PCT/CZ2013/000067
Authority: WO
Inventors: Pavel ŽÁK
Original assignee: Flamet S.R.O.
Priority date: 2012-05-28
Filing date: 2013-05-27
Publication date: 2013-12-05
Also published as: CZ2012347A3; CZ304324B6; EP2856025A1

Abstract

Vertical pellet burning equipment with a downwards burning flame, containing a burn-pot (1), a grate (2) and a supply bin (3). The gasifying space (4) situated above the grate (2) and connected with gravitation duct (5) to the supply bin (3) situated above the gravitation duct (5). Furthermore it comprises a device (6) to close pellet feeding, a primary air inlet (7), a secondary air inlet (8), an ignition opening (9), a jet (11), a control of air supply (12), and a closure of the ignition opening (13). Primary air inlet (7) is directed into the gasifying space (4) above the grate (2). Pyrolysis gases pass trough the grate (2) downwards into a jet (11) passage that guides the gases into a burn-pot (1), where they are mixed with secondary air and completely burnt with a visible flame. Originating from below the grate (2), the jet (11) passage is directed downwards. Optionally the jet (11) passage may be directed horizontally sidewards or U-shaped upwards.

Description

DOWNDRAFT VERTICAL PELLET BURNING EQUIPMENT

Technical Field

The invention concerns burning equipment, particularly vertical one for pellet burning, which contains a burn-pot, grate and supply bin.

State of the Art

Currently, a number of equipment has been known that enable pellet burning. There are also several design solutions in which the flame is directed downwards under the grate.

For example, the patent application CZ PV 1993-464 describes a boiler with two-level burning of solid fuel consisting of a gasifying chamber with a grate and a burn-pot. At the bottom part of the gasifying chamber there is a collecting duct above the grate which is connected via an extraction pipe with the burn-pot situated in the bottom part of the boiler. The gasifying chamber is situated between the burn-pot plate and the grate. An inlet of secondary air is conveniently located in the collection duct. One disadvantage of this burning equipment is that it is designed particularly for burning of big pieces of fuel, such as pieces of wood and coal, while it is not suitable for burning of pellets. This is associated with another disadvantage. The burning equipment cannot be operated at low outputs.

The patent CZ 302836 describes pellet burning equipment, particularly wooden pellets, for heating of apartments, houses or workshop buildings, by means of heat exchangers. The equipment consists of a burn-pot with a hopper at its top exceeding its sides, for gravitational feeding of pellets, with a grate with an air strangle above an ash pan, while the inlet into the burn-pot is closed with a door and the outlet goes to a burner. The door has an upper opening for air supply which prevents ignition of pellets in the hopper and at least one bottom opening that prevents formation of a vault from half-burnt pellets above the grate. A disadvantage of this burning equipment is its relative complexity and big size.

The patent application CZ PV 2006-523 describes a burner for pellets, especially from biomass, which also includes a feeding device to transport pellets to the grate and ignition equipment arranged under the grate. The grate is situated inside an internal pipe, overlapping the grate downwards to the ash pan and above the grate in form of a diffuser, while the inner pipe is surrounded with an outer pipe and together they form an inlet for combustion air above the grate. The ignition equipment is under the grate in form of a ceramic ignition body and above the grate there are barriers connected to the grating mechanism. A cover plate with guiding jets is situated between the upper end of the inner pipe and inner end of the outer pipe. Again, the disadvantage of this combustion equipment consists in the fact that, due to the feeder, its operation is quite noisy and therefore it is not suitable for residential premises. Moreover, it is relatively complicated and therefore also expensive. It also needs to be connected to an electric grid.

The provided overview of the existing state of technology indicates a number of disadvantages, while the most significant is that there is no simple equipment for pellet burning available that could be placed directly in residential premises.

The objective of the invention is a design of pellet burning equipment which is simple and thus also cheap and can be easily placed in residential premises.

Principle of the Invention

The mentioned shortcomings have been eliminated to a significant extent and the objectives hereof have been fulfilled by the pellet burning equipment, particularly vertical pellet burning equipment, with a burn-pot, grate and supply bin according to the invention, which consists in the fact that a gasifying space is situated above the grate connected with a gravitation duct and that the supply bin is situated above the gravitation duct and connected to it. The gravitation duct is conveniently used for thermal separation of the supply bin from the gasifying space below.

Under the grate there is a jet leading to the burn-pot. Alternatively, the jet can be arranged under the grate in the side wall of the pellet burning equipment and it is directed into the burn-pot. A convenient design features a jet directly pointed into the burn-pot.

It is convenient for the gravitation duct to contain a device that closes supply of pellets and closing of such a device can finish operation of the entire pellet burning equipment once the pellets burn out.

Further, it is expedient for the gasifying space to have at least one primary air inlet, while the most convenient option is a regulated primary air inlet which enables to control operation of the entire pellet burning equipment. To improve the burning, it is convenient for the burn-pot to contain at least one inlet of secondary air which should enter the burn-pot preferably along with combustible gases via the jet.

It is expedient for the gasifying space to contain at least one ignition opening that can be closed. Alternatively, the ignition opening can be the same as the primary air inlet.

It is also convenient for the burn-pot to have the front part transparent, while the burner jet points to the burn-pot and this creates interesting visual effects. This increases utility properties of the entire pellet burning equipment making it an attractive interior design element.

For operating reasons it is convenient to have an ash collection bottom under the grate and for the supply bin to have a lid to add more fuel. For practical reasons it is expedient for the supply bin to have a glass window in its front part.

The advantage of the design hereunder is that pellets continually burn out on the grate and no pellets can burn in the supply bin. Moreover, the chimney draft ensures underpressure in the gravitation duct and no cold combustible gases may get into the supply bin. Heating can be stopped simply by closing the pellet supply into the gravitation duct. The stove goes out once the pellets on the grate burn out.

The pellet burning equipment hereunder can be expediently used as a local source of thermal energy in apartments and dwelling houses. It is particularly suitable for low-energy and passive houses where its thermal output increases thermal comfort of the residents.

Other advantages of the pellet burning equipment hereunder include its simplicity, long burning time without having to add more fuel and fast and simple ignition with a gas mini burner. It is also very convenient that the pellet burning equipment does not depend on electric power supply and does not contain any moving parts, such as a screw, grate or ventilator that generate noise. In households the pellet burning equipment hereunder may serve as a convenient energy source with low rated output, minimum requirements for cleaning and ash removal because the ash burns with a flame when it falls through the grate and its quantity is minimized. Overview of the Figures

The invention will be explained in detail with a drawing, while Fig. 1 shows a detail cross section of the pellet burning equipment, Fig. 2 is an axonometric view of the entire pellet burning equipment with a partial section and with the flame directed downwards, Fig. 3 is an axonometric view of the entire pellet burning equipment with a partial section and with the flame directed horizontally and Fig. 4 is an axonometric view of the entire pellet burning equipment with a partial section and with the flame directed upwards.

Examples of the Performance of the Invention

Example 1

The vertical pellet burning equipment (Fig. 1 , Fig. 2) contains a burn-pot 1, grate 2 and supply bin 3. The burn-pot 1 is situated under the grate 2_and above the grate there is a gasifying space 4 connected with a gravitation duct 5. The supply bin 3 is above the gravitation duct 5 and discharged into it. In the gravitation duct 5 there are two devices 6 to close pellet supply. Two inlets or primary air 7_enter the gasifying space 4. Under the grate 2 there is a burner jet 1 directed into the burn- pot 1 Secondary air enters e burn-pot 1 via one input 8 through the jet JM . The burner jet 1_1 is directed into the burn-pot 1 and it creates interesting visual effects with the flame directed downwards. The gasifying space 4 contains one closing ignition opening 9. The burn-pot 1 has a transparent front part 10. The supply bin 3 has a transparent front part 14. The burn-pot 1 has a bottom 15 to collect ash. The supply bin 3 has a lid 16.

The vertical pellet burning equipment operates as follows: after the supply bin 3 is filled with pellets and after opening of the devices 6 that close pellet feeding into the gravitation duct 5, an ignited gas mini-burner (not shown) is inserted into the ignition opening 9 and it is left in place until a flame appears in the burn-pot Heating of the combustion products path increases the chimney draft which increases the flame. The vertical pellet burning equipment can be regulated by closing and opening of primary air inlets 7 and secondary air inlets 8.

The gasifying space 4 is a place for evaporation of water and gasification of pellets into combustible gases that pass through the grate 2 and at high temperatures they are mixed with secondary air in the jet lj. which results in complete combustion and spectacular flame. Also the charcoal burns out in the gasifying space 4. Ash falls through the grate 2 along with combustible gases and it remains on the bottom 15 of the burn-pot . The direction of the flame and the gravitation minimize generation of dust emissions.

Example 2

The vertical pellet burning equipment (Fig. 3) contains a burn-pot I, grate 2 and supply bin 3. The jet H is situated in the side wall 17 under the grate 2 and it is directed horizontally into the burn-pot I so that the resulting flame is directed horizontally.

Above the grate 2 there is the gasifying space 4 connected to the gravitation duct 5. The supply bin 3 is above the gravitation duct 5 and discharged into it. The gravitation duct 5 contains two (not shown) devices to close pellet feeding. Two inlets or primary air 7 enter the gasifying space 4.

Secondary air is brought into the burn-pot 1 via one (not shown) inlet through the jet . The burner jet H is directed into the burn-pot 1 and it creates interesting visual effects. The gasifying space 4 contains one (now shown) closing ignition opening. The burn-pot 1 has a transparent front part 10. The supply bin 3 has a transparent front part 14.

Under the grate 2 there is a bottom 15 to collect ash. The supply bin 3 has a lid 16.

The vertical pellet burning equipment operates as follows: after the supply bin 3 is filled with pellets and after opening of the devices that close pellet feeding into the gravitation duct 5, an ignited gas mini-burner (not shown) is inserted into the ignition opening and it is left in place until a flame appears in the burn-pot 1. Heating of the combustion products path increases the chimney draft which increases the flame. The vertical pellet burning equipment can be regulated by closing and opening of primary air inlets 7 and secondary air inlets.

The gasifying space 4 is a place for evaporation of water and gasification of pellets into combustible gases that pass through the grate 2 and at high temperatures they are mixed with secondary air in the jetH which results in complete combustion and spectacular flame. Also the charcoal burns out in the gasifying space 4. Ash falls through the grate 2 along with combustible gases and it remains on the bottom 15. The direction of the flame and the gravitation minimize generation of dust emissions.

Example 3

The vertical pellet burning equipment (Fig. 4) contains a burn-pot I, grate 2 and supply bin 3. The jet H is situated in the side wall 17 under the grate 2 and it is directed into the burn-pot so that the resulting flame is directed upwards. Above the grate 2 there is the gasifying space 4 connected to the gravitation duct 5. The supply bin 3 is above the gravitation duct 5 and discharged into it. The gravitation duct 5 contains two (not shown) devices to close pellet feeding. Two inlets or primary air 7 enter the gasifying space 4.

Secondary air is brought into the burn-pot via one (not shown) inlet through the jet 11. The burner jet H is directed into the burn-pot and it creates interesting visual effects. The gasifying space 4 contains one (now shown) closing ignition opening. The burn-pot 1 has a transparent front part 10. The supply bin 3 has a transparent front part 14. Under the grate 2 there is a bottom 15 to collect ash. The supply bin 3 has a lid 16.

The vertical pellet burning equipment operates as follows: after the supply bin 3 is filled with pellets and after opening of the devices that close pellet feeding into the gravitation duct 5, an ignited gas mini-burner (not shown) is inserted into the ignition opening and it is left in place until a flame appears in the burn-pot . Heating of the combustion products path increases the chimney draft which increases the flame. The vertical pellet burning equipment can be regulated by closing and opening of primary air inlets 7 and secondary air inlets.

The gasifying space 4 is a place for evaporation of water and gasification of pellets into combustible gases that pass through the grate 2 and at high temperatures they are mixed with secondary air in the jet l which results in complete combustion and spectacular flame. Also the charcoal burns out in the gasifying space 4. Ash falls through the grate 2 along with combustible gases and it remains on the bottom 15. The direction of the flame and the gravitation minimize generation of dust emissions. Industrial Application

The pellet burning equipment under the invention can be used separately for burning of various types of fuel, particularly various types of pellets, or as a part of pellet burning equipment which also contains a conventional fireplace stove or a stove with a hot-water exchanger.

Claims

Patent claims

1. A pellet burning equipment, particularly vertical pellet burning equipment, containing a burn-pot (1), grate (2) and supply bin (3), characterized by the fact, that the gasifying space (4) situated above the grate (2) is connected to the gravitation duct (5), the supply bin (3) is above the gravitation duct (5) and discharged into it and under the grate (2) there is the jet (11) directed into the burn-pot (1).

2. The pellet burning equipment under the claim 1 characterized by the fact that the jet (1 ) directed into the do burn-pot (1) is situated in the side wall (17) under the grate (2).

3. The pellet burning equipment under the claim 2 characterized by the fact that the jet (11) is directed into the burn-pot (1) directly.

4. The pellet burning equipment under any of the preceding claims characterized by the fact that the gravitation duct (5) contains at least one device (6) to close the pellet feeding.

5. The pellet burning equipment under any of the preceding claims characterized by the fact that the gasifying space (4) contains at least one primary air inlet (7).

6. The pellet burning equipment under any of the preceding claims characterized by the fact that the burn-pot (1) contains at least one secondary air inlet (8).

7. The pellet burning equipment under any of the preceding claims characterized by the fact, that the gasifying space (4) contains at least one closing ignition opening (9).

8. The pellet burning equipment under any of the preceding claims characterized by the fact that the burn-pot (1) has a transparent front part (10).

9. The pellet burning equipment under any of the preceding claims characterized by the fact that the jet (11) is directed into the burn-pot (1) to form interesting visual effects.

10. The pellet burning equipment under any of the preceding claims characterized by the fact that the bottom (15) to collect ash is situated under the grate (2).

1. The pellet burning equipment under any of the preceding claims characterized by the fact that supply bin (3) has a lid (16).