US3531230A - Internally fired blast burner - Google Patents

Description

Sept. 29, 19% E. APOLENARSKI 3y53fivg3fl INTERNALLY FIRED BLAST BURNER Filed May 21, 1968 2 Sheets-Sheet 1 I'm/WNW: E. APoZlncZ/sx.

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Filed May 21, 1968 2 Sheets-Sheet 3 m In W far:

P WCLLs KL as o ATTorLN 635 United States Patent 3,531,230 INTERNALLY FIRED BLAST BURNER Edmund Apolinarski, 17 Piusstrasse, 473 Ahlen, Westphalia, Germany Filed May 21, 1968, Ser. No. 730,779 Claims priority, application Germany, Apr. 21, 1967, 1,551,760 Int. Cl. F23d 15/02 US. Cl. 431-352 8 Claims ABSTRACT OF THE DISCLOSURE A blast blower of the type having air supplying means concentrically enclosing the gas flow and provided with a conical regulating device at the inlet of the fuel flow and forwardly located mixing chambers. The blower of the present invention is particularly characterized in that these mixing chambers extend conically and that nozzles concentrically surrounding the mixing chambers extend downwardly in relation to the flow and at an acute angle to the axis of the burner to supply fresh air along c0- axial conical surfaces; an annular recoil wall is located opposite the regulating device and serves as the closure for the first mixing chamber, the wall being inclined downwardly in relation to the flow and being provided with jets, while a ring guide which is inclined downwardly in relation to the flow serves as a closure for the second mixing chamber and to narrow the combusion mixture.

This invention relates to firing plants and refers more particularly to a blast blower and burner having air supplying means concentrically enclosing the gas supply and provided with a conical regulating device at the inlet of the fuel flow.

Blast blowers for fuels of different types have been constructed for gases, liquids and various carbonaceous media.

Blast blowers of this type may be divided into those wherein air in the form of an eddy current is conducted through openings located concentrically around the gas supply, as well as other blast blowers wherein air is directed along a straight line and inclined to the main axis of the blower. There are also well introduced constructions of eddy blast blowers with one or two mixing chambers located in front of the gas flow.

An object of the present invention is the provision of a blast blower for gas and liquids of all types to be used for all fuels and consisting of a single construction of a few parts.

Another object is to provision of a comparatively small blower the various parts of which cooperate to produce a very quick and effective mixing, thereby producing an all gas burner having a CO-content of 0.0000.06 percent by volume in exhaust when operating with various different types of gases, such as long distance gas supply, natural gas, butane and propane, but also with liquid fuels, to produce an output up to 90,000 kcal./hr. at a fuel chamber load of up to 280,000 W.E./CBM.

Other objects of the present invention will become apparent in the course of the following specification.

In the accomplishment of the objectives of the present invention it was found desirable to use a blast blower with air supplying means concentrically enclosing the gas regulator at the inlet of the fuel supply, and to provide Patented Sept. 29, 1970 ice supply and provided with a conical axially movable this blast blower with mixing chambers which extend conically, which are located ahead of the regulator and which consist of a single structural piece.

Another improvement of the present invention consists in that radially extending jet nozzles are arranged in the two mixing chambers in several concentrical circles at about equal axial and radial distances and that at least one ring of the jet nozzles is inclined parallel to the outer surface of the recoil wall.

An additional improvement of the present invention consists in that the regulator which is made of brass cooperates with a nozzle seat at the outer edge of a nozzle insert screwed into the gas inlet channel, whereby the nozzle cross section is adjusted by turning a pin extending outwardly through the nozzle insert as well as through the channel and screw threads in the socket.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example only, a preferred embodiment 'of the inventive idea.

In the drawings:

FIG. 1 is a longitudinal section through a blast blower of the present invention, some parts being shown in side view.

FIG. 2 is a rear view, partly in section along the line IIII of FIG. 1.

FIG. 3 is a top view of the upper side of a socket of a mixing head with nozzle and ignition elements.

FIG. 4 is a side view of the device of FIG. 3.

FIG. 1 illustrates an apparatus having a blower 1 and a casing 4 connected with the blower by flanges 2 and 3 and having an inserted mixing head 5 with a gas conduit 6 extending between a switching device 7 used to operate the blower and a gas inlet channel 8 located in the mixing head 5.

The casing consists of an upper casing part 9 and a lower casing part 10 which are mounted one on top of the other and joined by flanges 10 and 11 with an intermediate sealing ring 12.

The flange 11 which carries a sealing ring 13, is also used as a support for mounting the apparatus into an inlet opening 15 of a furnace chamber 16.

A socket 20 of the mixing chamber 5 consists of one piece with the lower casing part 10. A chamber-forming part 21 is mounted on top of the socket 20 approximately on the level of the connecting flanges 10 and 11 and is connected therewith by screws 22.

The part 21 which extends coaxially in the upper casing part 9, is divided into a precombustion chamber 24 and a combustion chamber 25. An annular chamber 30 is provided between the walls 26 and 27 of the upper casing part 9. The cross section of the chamber 30 becomes smaller from left to rightlooking in the direction of FIG. 1and it is quite narrow at its outer end due to the provision of an outwardly extending flange ring 31 at the end of the chamber 21.

Ring-shaped projections 35 and 36 are located between the two chambers 24 and 25 and at the end of the combustion chamber 25. The rear surfaces 37 and 38 of the projections 35 and 36 are inclined inwardly. Thus at the end of each chamber 24 and 25 there are frusto-conical outlet cross sections.

The casing 4 has a somewhat similarly shaped and portion. The wall of the upper casing part 9 curves inwardly 3 behind the ring 31 of the chamber 21 and itself forms a ring 41 with inclined surfaces which encloses an outlet opening 40.

The socket made of one part with the lower casing portion 10 has a side inlet 45 for the gas conduit 6 leading into the gas inlet channel 8 which continues as a curved part 46 and then extends coaxially relatively to the chamber 21 and the casing 4.

A nozzle 50 constituting the inner closure of the channel 8, includes a nozzle insert 52 which is screwed by screws 51 into the end opening of the channel 8, and a conical closure 53 at the end of a shaft 54. The shaft 54 is initially coaxially guided through the nozzle insert 52 and the coaxial portion of the channel 8 and then is connected by its screw threaded portion 55 with the inner screw threads 56 of the socket 20. The threaded part 55 in continued as an end bolt 57 extending outwardly through the flange 2 of the casing. When the nozzle 50 is closed, the conical surface 58 of the closure 53 engages a correspondingly shaped seat 59 at the upper edge of the nozzle insert 52.

FIG. 1 shows in full lines an intermediate position of the closure 53. Thin broken lines 60 show the closure 53 in its fully closed position while thin broken lines 61 show the closure 53 in its fully open position.

The precombustion chamber 24 is provided with a circumferentially disposed ring of bore holes which are forwardly inclined and are used for letting in primary air. The central axis of each bore hole 70 points angularly forward to the central axis of the chamber 21. On the other hand, the chamber 25 is provided with several bore holes 71 which annularly enclose the chamber 25 and which are so shaped that their central axes point directly to the furnace combustion chamber 16 without touching or passing through any other part of the burner. This arrangement of the bore holes 71 greatly facilitates the passage of the flame from the combustion chamber 25 into the furnace chamber 16 without touching any walls of the chambers and casings.

FIGS. 3 and 4 show that in addition to the nozzle insert 52, there are various other members provided in the socket 20 which extend out of a front surface 75. These members are parts of the ignition system. An ignition flame burner 77 is located close to the ignition electrode 76. A key pin 78 also extends out of the front surface preferably to the combustion chamber 25. Conduits 79, 80 and 81 of the above-described members are all attached to the switching device 7 which directs the gas flow depending upon the flame, A prior art switching device having, for example, a filter and safety means against gas interruption, which can be used for the purposes of the present invention and which was found to be particularly etfective, is the ionisation switching device sold by the firm of Mayer & Christe.

While the rotor of the blower 1 is the same as the rotors now available on the market, the casing of the blower is adapted to the specific requirements of the present invention, in that, for example, the connection piece 85 is connected by flanges to the burner casing 4 outside of its center, The shape of the air inlet channels is also of importance for the purposes of the present invention. The casing of the blower 1 is provided with segment-shaped inlet openings 86 which are in alignment with correspondingly shaped openings 87 of a cover 88 when the inlet side is completely open, the cover 88 being rotatably mounted in the blower. By turning the cover 88 relatively to the front side of the blower provided with the inlet openings 86, the cross-sectional inlet areas of the blower can be varied without steps. The amount of combustion air supplied to the burner can be conveniently regulated in this manner without having to change the rotational speed of the blower.

To provide a good combustion efficiency and a flame shape corresponding to the shape of the burner, it is of importance that the amount of supplied air should be Well regulated with respect to the amount of supplied gas. Consequently, the cross-sectional areas of the inlet of the nozzle 50 and the cross sections of the inlet openings of the blower 1 should be always adjusted jointly and in a specific relationship to each other.

By way of example, a specific relationship of predetermined inlet cross sections of nozzle 50 and the inlet side of the blower 1 can be effected by providing certain markings upon the edges of the cover 88 and adjacent wall of the blower which would correspond to specific markings corresponding to the number of revolutions of the nozzle shaft 54.

In case comparatively fine screw threads 56 for the threaded shaft section 55 have been used and consequently, a comparatively large number of revolutions is possible between the two possible end positions of the closure 55, a simple counter can be used which is mechanically connected with the shaft 54 and which indicates its position.

A table indicating markings of the cover 88 and of the shaft 54 which correspond to each other, can be used for providing in a simple manner the best possible setting for the burner in wide output ranges.

However, as shown for example in FIG. 1, the shaft 54 can be coupled with the cover 88 by means of bevel gears. For example, a pinion 90 upon the end pin 57 can mesh with an intermediate gear 91 which meshes with a toothed ring 92 upon the edge of the cover 88. In that case the adjustment can be carried out merely by turning the intermediate gear 91.

The intermediate gear 91 can be turned manually, or it can be operated from a distance by a servomotor which receives its switching impulses from a thermostatic actuating device.

The burner-blower of the present invention is operated as follows:

After the blower 1 has been started, a current of air is introduced through the connection piece 85 into the lower casing part 10. This air fills the chamber 30 around the chamber part 21 of the mixing head 5 and leaves the burner partly as a primary air current through the bore holes 70 and 71 and the chambers 24 and 25, or as a secondary air current after having blown past the flange ring 31.

As soon as the blower 1 is constantly supplying a predetermined amount of combustion air to the mixing head 5, the switching device 7 will cause the opening of the gas conduit 6, so that gas will flow through the annular space between the seat 59 and the closure 53 into the precombustion chamber 24. There the gas flow intersects and meets the primary combustion air entering through the bore holes 70, so that a thorough mixing takes place. The ignition burner which has been previously ignited by the ignition electrode 76, produces an immediate combustion of the air-gas mixture and thus produces a flame directed into the furnace chamber 16 and projecting from the combustion chamber 25.

The closure 53 as well as the nozzle insert 52 are made of tin. There is no danger that these parts will be overheated due to the manner in which the flame is formed in the chamber 21, particularly since in the chamber 24 only an intensive mixing of air and gas takes place, While the flame starts only in the combustion chamber 25.

The blower casing 1, the cover 88 and the burner casing 4, including the socket 20 and the chamber part 21, are all made of duralumin, preferably by casting. The shape of the chamber part 21 and of the upper casing part in accordance with the present invention provide such a flow and distribution of the primary as well as secondary amounts of air that the walls are always cooled automatically and are not subjected to any overhanging. Therefore, the burner of the present invention can be made comparatively small and yet can be loaded thermically to the extreme. The importance of the flange ring 31 which above all produces a damming of the air current in the chamber 30,

so that the primary air current can be pressed through the openings 70 and 71, and in this connection the importance of the annular projections 35 and 36 and their rear surfaces 37 and 38, has been indicated already.

If the output of the burner is to be increased, the intercircles at substantially equal axial and radial distances, at least one of said circles consisting of bore holes the axes of which extend parallel to the rear surface of the firstmentioned projection.

3. In combination with a furnace having an inlet openmediate wheel 91 is turned so that the segment-shaped 5 ing, a blast blower in accordance with claim '1, wherein openings 86 and 87 move over each other to a greater the second-mentioned casing consists of two parts having extent and so that the flow passage between the seat 59 and interconnected flanges, one of said flanges being adapted the outer surface 58 of the closure 53 is increased. This to engage the inlet opening of the furnace. type of adjustment makes possible a regulation without 4. A blast blower in accordance with claim 3, wherein steps in extremely wide ranges, for example between 5000 said gas supplying means comprise a socket carrying said W.E. and 120,000 W.E./ hr. without any drop in efiiciency. regulating valve and integral with one of the parts of the The following table indicates the results of a technical second-mentioned casing, the first-mentioned casing being examination of the blast blower of the present invention screwed upon id Socket y the German Union of Gas and Water Specialists 5. A blast blower in accordance with claim 1, wherein in Frankfurt'Main: said regulating valve comprises a conical valve body and a valve seat extending perpendicularly to the first-men- Gas tioned projection. Long dist; Methane Pmpime 6. A blast blower in accordance with claim 5, wherein Duration of experisaid valve seat further comprises a conical surface adapted g to be engaged by said valve body and wherein said regulat- .075 1. 05 1. 05 1. 05 1.05 ing valve further comprises a valve rod connected with said Load keel/hr 88.000 15.000 88.000 15. 000 88. 000 000 valve y and movable to p and close said valve,

Gas

Long dist. Methane Butane Flow pressure from burner, mm. W.(7 80 80 200 200 270 270 Air excess, percent 1 3 18 20 1 1 17 56 0.5 6 19 50 CO measured in exhaust, Vol. pereent 0. 06 0. 02 0.01 0. 06 0. 02 0. 02 O. 04 0. 02 0. 02 0 0 0 Recalculated undiluted, vol. percent 0.0606 0. 0204 0.018 0.077 0.020 20.0202 0. 47 0.0312 0.02 0 0 0 G02 dry measured in exhaust, v01. percent 9.3 9.6 3.4 7.7 11.6 11.6 10 7.5 14 13.3 11 s 9.4 Pressures:

In fire chamber, mm. w.c 5 +5 5 +5 5 +5 5 +5 --5 +5 5 Air after blowing, mm. w.e +17 +6 +1 -9 +17 +5 +1 10 +17 +6 +1 l0 Gas in nozzle, mm. w.e Temperature of combusted air, 22 22 21 21 21 22 21 2O 21 21 21 20 It is apparent that the example described above has been said valve rod having an end portion located outside of given solely by way of illustration and not by way of limisaid casings, means connected with said end portion for tation and that it is capable of many variations and modifiactuating said valve rod, said air supplying means having cations within the scope of the present invention. means regulating the amount of supplied air, and means What is claimed is: operatively connecting said air regulating means with said 1. A blast blower comprising an inner casing having a valve rod actuating means. longitudinal axis, gas supplying means having a conical 7. A blast blower in accordance with claim 6, wherein regulating valve located in said casing centrally in relation said air supplying means comprise a casing communicating to said axis, said casing having a conically widening porwith said mixing chamber and having radially disposed, tion terminating in an outlet and enclosing a precombussegment-like openings and wherein said air regulating tion chamber communicating with said valve and a commeans comprise a rotary cover adapted to close said openbustion chamber located between said precombustion ings and having segment-like openings adapted to be partly chamber and said outlet and communicating therewith, and totally aligned with the first-mentioned openings. another casing enclosing the first-mentioned casing and 8. A blast blower in accordance with claim 7, wherein coaxial therewith, the two casings being spaced from each the means connecting the air regulating means with the other, whereby a substantially annular chamber is provalve rod actuating means comprise a gear drive convided between the two casings, means supplying air to said necting said cover with the valve rod actuating means. annular chamber, the first-mentioned casing having concentrical radial bore holes with central axes extending at an References Clted acute angle to said longitudinal axis and inclined in rela- FOREIGN PATENTS tion to said outlet, an inwardly extending annular projection separating said precombustion chamber from said 746,061 2/ 1933 France. combustion chamber, said projection having a rear sur- 1,388,590 12/1964 France. face inclined toward said longitudinal axis and said outlet, 476,614 5/ 1929 Germany. and another inwardly extending annular projection en 573,335 3/1933 Germany. closing said outlet and having a rear surface inclined to- Ward said longitudinal aXiS FREDERICK L. MATTESON, JR., Primary Examiner 2. A blast blower in accordance with claim 1, wherein said radial bore holes are arranged in several concentrical H. B. RAMEY, Assistant Examiner

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