DE29507040U1 - Atmospheric gas burner - Google Patents

Description

.::. ^: .. ^: \. ^: T · EU0H1 1995

Ooh. Vaillant GmbH u. Co. GM 1360

The invention relates to a gas burner according to the preamble of the claim.

In such atmospheric gas burners, a distribution plate with a defined slot arrangement is used to even out the flow of the gas-air mixture inside the burner elements. In the partial load range, this leads to a deterioration in pollutant emissions because the burner surface load becomes uneven across the burner surface.

The aim of the invention is to avoid these disadvantages and to propose a gas burner of the type mentioned at the beginning, which is characterized by a favorable flow inside the burner elements both at partial load and at nominal load.

According to the invention, this is achieved in a gas burner of the type mentioned at the outset by the characterizing features of the claim.

In the partial load range, in which a richer gas-air mixture is present and the outflow velocity of the combustion mixture from the combustion mixture outflow openings of the burner elements is low

is, the flames stabilize near the combustion mixture outlet openings, which leads to a high energy input into the burner elements. The resulting increase in temperature of the burner elements causes the bimetal throttle to move into the flow to the mixing chamber, thus evening out the flow. At a nominal load or higher, the exit speed of the combustion mixture increases. The increase in the exit speed due to the gas/air flow is higher than the increase in the flame speed, so that the reaction front stabilizes at a greater distance from the top of the burner plate. As a result, there is less energy input into the burner elements and thus a drop in the temperature of the burner elements and the gas mixture, which further opens up the flow to the mixing chamber, as the bimetal moves out of the mixture flow.

The invention will now be explained in more detail with reference to the drawing.

Showing:

Fig. 1 a section through a burner element,

Fig. 2 and 5 a bimetallic choke in section in cold and warm state,

Fig. 3 and 6 sections through the burner element according to the line III/VI-III/VI in cold and warm state,

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Figures 4 and 7: Sections through the burner element along line IV/VII-IV/VII in cold and hot state.

The same reference symbols indicate the same details in all figures.

The burner element 1 according to the invention has a mixing tube 2 which is aligned coaxially with a gas nozzle 15 and is connected to a mixing chamber 4 via a bend 3, so that the burner element 1 has a substantially U-shaped configuration with an L-shaped flow path for the gas-air mixture.

The top of the mixing chamber 4 is provided with combustion mixture outlet openings 5.

A bimetallic throttle 7 is attached to the wall 16 of the bend 3 facing away from the inlet opening 6 of the mixing tube 2. As can be seen from Fig. 2, this has a substantially L-shaped configuration when cold, whereby as the temperature increases, which occurs during partial load operation due to the stabilization of the flames near the top 17 of the mixing chamber 4 due to the convection and radiation of the flames, the angle enclosed by the two legs 8 increases and the bimetallic throttle 7 takes on a substantially elongated configuration, as can be seen from Fig. 5. As a result, the overflow cross-section from the mixing tube 2 into the mixing chamber 4 is controlled depending on the temperature of the burner element 1 and thus

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also the flow inside the burner element 1. This leads to a reduction in the outflow at partial load and to a more even outflow of the combustion mixture from the combustion mixture outflow openings 5 over the entire load range, since the flow to the combustion mixture outflow openings 5 located in the front area 13 of the burner elements 1 is impeded by the bimetallic throttle 7.

At a low temperature in the burner element 1, which occurs during operation in the nominal load range due to the fact that the flames then stabilize at a greater distance from the top of the burner elements due to the increased mixture volume input, the bimetal throttle 7 releases the flow so that an increased outflow in the rear area 12 of the burner element 1 is avoided and in this case too, a uniform outflow over the entire burner element 1 results.

As can be seen from Fig. 3 and 4 or 6 and 7, the bimetal throttle 1 has slots 10 which extend from two opposite edges of the bimetal throttle 7 into the latter, so that mixture can still reach the rear area of the burner. One leg 9 of the bimetal throttle 7 has an essentially trapezoidal outline, with the wider area being connected to the leg 8.

Above the area between the gas nozzle 15 and the inlet opening 6 of the mixing tube 2, a

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A non-return grille 11 is arranged on a support 14 which passes through the mixing pipes 2.

Claims (1)

Joh. Vaillant GmbH u. Co. GM 1360 CLAIM Atmospheric gas burner with at least one essentially U-shaped burner element, which has a mixing tube aligned with a gas nozzle and axially spaced from it and a mixing chamber connected to it via a bend, the upper side of which is provided with combustion mixture outlet openings, wherein a distribution plate protruding into the interior of the burner element is arranged in the region of the bend, characterized in that the distribution plate is designed as a bimetallic throttle (7) which has a trapezoidal leg (8) mounted on one side at its wider end with openings or slots (10) which moves into the flow leading to the mixing chamber (4) as the temperature increases.