US2652011A - Pulverized fuel burner - Google Patents

Description

QW W53 8. G. VAN RAMSHORST 2,652,011

PULVERIZED FUEL BURNER Filed June 1, 1948 Patented Sept. 15, 1953 2,652,,tll

PULVERIZED FUEL BURNER Steven G. van Ramshorst, Dordrecht, Netherlands, assignor to Maria Justina van Tongeren- Boers, Heemstede, Netherlands Application June 1, 1948, Serial No. 30,495 In the Netherlands June 17, 1947 3 Claims.

This invention relates to a burner for use with pulverized fuel, which is delivered mixed with air to the chamber in which combustion takes place. In burners of this type it is desirable that the fuel should be delivered into the combustion chamber as a uniform mixture and that the particles of fuel should be maintained in suspension for a sufiicient length of time to permit them to be completely consumed before being deposited on the floor of the furnace.

The present invention involves the provision of a burner which is arranged to obtain a complete and uniform mixing of the fuel and air and includes means which prevent the fuel in said mixture from dropping by gravity before being conveyed into the furnace through a sufficient distance, and thus afford them an oppor tunity to be completely burnt before reaching the ash on the furnace floor.

The novel burner is of the known type including a more or less horizontal tubular member having, in addition to a substantially axial nozzle for connection to a compressed air feed pipe, a nozzle for connection to a pulverized fuel supply pipe, a more or less horizontal deflector plate being provided within said tubular member and beneath the said last nozzle in such manner as to allow the incoming compressed air to flow both over and underneath said deflector. Now, in accordance with the invention, the said deflector, together with the wall of the compressed air feed pipe and that of the more or less tangential inlet opening of the fuel supply pipe, constitutes an ejector adapted to induce the mixture of air and fuel substantially axially into the tubular member in the form of a stream, which at the lower side is confined by the deflector.

In a burner as defined hereinbefore, the fuel to be delivered to the combustion chamber is not deposited on the bottom of the tubular member and swept across the same towards the mouth of said member by the current of air discharged below the front edge of the deflector, but is maintained in suspension in the upper air current, and is prevented from being so deposited by the lower current. Thus, the lower current acts as a carrier, which, while preventing the fuel from dropping by gravity, immediately in front of the burner mouth, to the floor of the furnace, serves to maintain the fuel particles delivered by the burner suspended during a relatively long time so as to enable them to be completely consumed.

The deflector plate could extend in forward direction to close to the burner mouth, since the lower and the upper air currents have individual functions, but this is not necessary.

The annexed drawing illustrates, by way of example only, a burner designed in accordance with the invention, Fig. 1 being a plan view thereof, Fig. 2 a sectional elevation along the line 11-11 in Fig. 1, and Fig. 3 a rear elevational view.

The numeral 4 designates the more or less horizontal tubular member, 5 the nozzle, opening into the top wall of said member, for connection to the pulverized fuel supply pipe not shown, 6 the nozzle, opening axially into said member, for connection to the compressed air feed pipe. Provided inside the tubular member, at a level about midway between top and bottom thereof, is the more or less horizontal partition or deflector plate 1.

As will be seen from Fig. 2, the nozzle 5 is curved so as to open about tangentially into the tubular member 4. Immediately at the rear of said opening is the throat 8 of the acceleration cone of the ejector, said cone being confined by the rear portion of the deflector l and the top Wall of nozzle 8, whereas the pressure cone of the ejector is confined by the wall around the mouth of nozzle 5 and by that portion of the deflector which is located beneath said mouth.

In accordance with the drawing, the deflector 1 extends in forwarddirection to a point substantially vertically below the front edge of the mouth of nozzle 5. However, as already stated, it could as well extend to the mouth of tubular member 4.

Attention is drawn to the fact that, in accordance with the drawing, the passageway below the deflector l is also constituted as an acceleration cone, the throat ll of which has substantially the same width as throat 8 and is located near the front edge of the deflector. Owing thereto, the velocity of the lower or carrier air-current will exceed that of the upper current (which, as will be understood, is retarded by the pulverized fuel suspended therein), and this fact still increases the carrying capacity of the lower current. Meanwhile it will be appreciated that the lower air-current will also act as a carrier if the deflector I should be provided at a lower level than midway between top and bottom of the tubular member, that is to say, if the strength of the upper current should exceed that of the lower current.

Although the specification so far refers to a burner, it is obvious that the device under review can also be used for other purposes, e. g. for conveying pulverized or granular material or dust not intended to be delivered into a furnace, and that said device comes Within the scope and the 3 V spirit of the invention irrespective of the purpose for which it may be employed.

What I claim is:

1. A burner of the type described comprising a horizontally arranged tube adapted to be connected at one end to a conduit means for a supply of compressed air, saidtube having a bottom wall and a top wall, said top wall being formed with an opening adapted for communication with 'a nozzle for pulverized fuel, a partitiontr'ans'ver's'ely disposed in a portion of the tube and completely separating the bottom and 'tjop'wall s'at 's'ai'd'portion of the tube, said partition being spaced from the top and bottom walls and havingone of its ends underlying and spaced forwardly of the opening, the opposing end of the partition terminating rearwardly of the opening and adjacent to the end of the tube adapted to be connected to the conduit means, said partition being inclined downwardly at its forward end relative to the bottom wall of the tube and defining a tapering nozzle with the bottom wan r the'tubathecrcss sectional area of the tube above the forward end of the partition being larger than the cross sectional area of the tube above the rearward end of the partition and the forward end of the partition and top wall of the tube defining a mixing zone where the ai r ismixed with the fuel.

2. A burner of the type describedcomprising a horizontally arranged tube adapted to be connected at one end to a conduit means for a supply of compressed air, said tube having a bottom wall and a top wall, said top wall being formed with an opening adapted for communication with P a nozzle for pulverized fuel, a partition transversely disposed in a portion of the tube and completely separating the bottom and top walls at said portion of the tube, said partition being spaced from the top and bottom walls and having one of its ends underlying and spaced forwardly of the opening, the opposing end of the partition terminating rearwardly of the opening and adjacent to the end of the tube adapted to be connected to the conduit means, said partition, being inclined downwardly at its forward, end; relative to the bottom wall of the tube'and defining a tapering nozzle with the bottom wall of the tube, the cross sectional area of the tube above the forward end of the partition being larger than the cross sectional area of the tube above the rearward end of the partition and the forward end of the partition and top Wall of the tube defining a mixing zone where the air is mixed with the fuel, and the cross sectional area of the tube forwardly of the partition being constant,

the'air flowing from below the forward end of the partition acting as a continuation of the partition and as a carrier for the mixture flowing from above the partition.

3. 'A burner of the type described comprising a' substantially horizontally arranged tube adapted to be connected at one end to a compressed air pipe, said tube having a straight bottom wall and atop wall formed with an opening, a nozzle for pulverized fuel communicating with said opening, said top wall tapering in the direction of flow of air from the end of the tube atthe air pipe to the nozzle opening, the cross sectional area of the tube at the nozzle opening being larger than the cross sectional area of the tube rearwardly of the said opening and the'cro'sssectional area being tapered in the direction ofthe flow, the cross sectional'area forwardly bf the opening being reduced from the area at thenozzle opening and being substantially constant-a partition transversely disposed entirely facross the tube between the top and bottom walls and being inclined downwardly in the direction'of flow relative to the bottomwall and having'its front inclined end directly underlying'the nozzle opening and terminating-forwardly thereof.

STEVEN G. VAN RAMSHORST.

References Cited inthe file of this patent UNITED STATES PATENTS Number Name Date 738,131 Weaver 'Sept. 1, 1903 1,213,821 Bergman Jan. 30,1917 1,213,822 Bergman Jan. 30, 1917 1,535,903 Collins 'Apr. 28, 1925 1,971,328 Byrne' et al Aug. 28,1934 2,494,070 Thomas Jan. 10,1950

Images