US2071678A - Gas generating boiler for central heating - Google Patents

Description

Feb 23, 1937.. J Y 2,@?1,578

GAS GENERATING BOILER FOR CENTRAL HEATING Filed Oct. 5, 1935 Inventor Julz'enfieiidy A'iftqmqy;

Patented Feb. 23, 1937 UNITED STATES PATENT OFFICE GAS GENERATING BOILER FOR CENTRAL HEATING Julien Bellay, Brussels, Belgium Application October 5, 1935, Serial No. 43,762 In Belgium May ll, 1935 Claims.

air admissions distributed over all the height of said chamber.

The gasifying air is introduced in the mass of fuel fed into the fire-box in sufiicient quantity to obtain a maximum production of gas, without however being in excess, so as to insure that the combustion of the gas will only take place in the combustion chamber by means of the air admitted to that end.

The gasifying air is generally blown in by means vof an intermittently working electric fan, controlled by a thermostat or any other device depending on the water temperature or on the temperature of the premises to be heated. During the non-operating periods of the fan, which can be of more or less long duration and vary between large limits for a definite plant, the production of gas diminishes gradually as well as the temperature in the fire-box or hearth. It is nevertheless necessary, when the fan is set in motion again, that the reaction in the generator as well as the reaction in the combustion chamber should be started immediately or else the fire would probably be extinguished or what is more serious, an explosion would probably be provoked if the gas is not burnt at its exit from the generator.

This danger is especially encountered when the external temperature is not very low, which results in long non-operating periods of the fan.

In previous patents, I havedescribed a gasiiying air admission device, acting through a very narrow slit extending along all the depth of the fire-box, so as to realize a practically instant gasifying, at very high temperature (ash fusion gasifying). This obviates to a large extent, the above mentioned dangers, without however insuring as yet, full safety. But these dangersexist to a much higher degree with boilers having firers 5 gas as soon as given off.

To create this starting point, the atmospheric air admitted in the fire-box, when the fan is stopped, and due to the depression in the fire-box, is compelled to come out at the same point thus realizing at this point, a zone of fuel of lesser resistance to air passage.

In practice, different manners of carrying this into efiect can be adopted. The discharge aperture of the feeding hopper or funnel extends sub stantially along the back half of the fire box, the front half being free.

The fuel falls by gravity, into the fire-box and provides towards the front part of the fire-box, a natural slope inclined at about 45. The gasifying air admission pipe extends from the back end 15 of the fire box up to a certain distance from the front end in such a manner that the front end of the aperture of this pipe issues at a very slight distance from the inclined surface of the fuel bed.

In other words, the pipe is arranged in relation 0 to the mass of fuel in,the fire-box in such a manner that at the end of this pipe, the thickness of the fuel layer to be traversed by the air is considerably less than in any other location, whereby at this point, the resistance to air passage is very much reduced.

When the fan is stopped, the external air being simply admitted through the natural depression in the fire-box, this air will tend to issue at'the point of lesser resistance, and reaction and dis- 0 charge of gas will always take place at this point; this discharge will be very slight and in practice the gas produced will burn straight away forming a small flame which plays the part of a pilot to instantaneously light the gas produced as soon as the fan is set in motion.

The pipe may even be lengthened by a small tube nearly flush with the inclined surface of the fuel slope and producing also a continuous pilot flame.

An example of realization of the invention is shown in the appended drawing, in combination to a special kind of boiler also forming part of the invention.

In the drawing: 45

Figure 1 is a vertical cross section along line I-I of Figure 2,

Figure 2 is a horizontal cross section along line 11-11 of Figure 1,

Figure 3 is a vertical section along line III-III of Figure 1.

The boiler illustrated, of the mentioned type, with internal fire-box forming gas generator, with above it a combustion chamber, is double in so far that two complete independent fire-boxes are pro-' to an independent heating. circuit, both circuits being connected to the main departure and arrival pipes of a central heating plant This boiler with two independent fire-boxes is an appreciable improvement as regards usual I boilers; these last named boilers are in fact, generally very difficult to manage during very cold periods or during transitory seasons (spring and autumn).

If the boiler is calculated for a maximum temperature or if in other words, the boiler is chosen of larger capacity than is normally necessary, it is very easy to manage the plant during severe temperature, but on the other hand, during normal temperature (spring and beginning of autumn) the heating is much too intensive and if it is desired not to exceed normal temperature there is danger of extinguishing the fire, in spite of the pilot device according to this invention. In

any event, it is very difficult to maintain a normal temperature.

Inversely if the boiler has been chosen so as to allow easy maintenance of normal temperature during mild temperatures, it will practically be impossibleto heat up sufficiently during severe temperature. With the double fire-box boiler, management is greatly simplified at any time with use of pilot.

During severe temperature the two fire-boxes or hearths are put into service, while during transitional periods, only one of the fire-boxes is put into service, the other one being stopped with its water circuit cut off from the heating conduits.

The boiler body according to the invention is in the form of a rectangular parallelepiped I the I by means of the hopper wall 9, the outside walls of the hopper I 0, bottom of the fire-box and tubular device 6.

The hot water leaves through outlet II towards a stop tap not shown, joining to the main outgoing pipe 22 of the central heating plant; the cold water returns at l2, through a tap not shown, connecting to the main common incoming pipe 23. Thus at will, it is possible to cut out of the heating circuit one or the other fire-box.

The hopper extends along the whole depth or breadth of the boiler; it preferably becomes narrower towards the bottom and its bottom I3 is arched in form of a roof. 'The hopper is provided with a slot IQ for feeding each fire-box by gravity.

This slot (Figure 3) extends nearly along the whole back half of the depth or breadth of the fireboxes, so as to feed into the fire-boxes a mass of fuel i5 which in the direction of the clean out door (in front) automatically attains the inclination of the natural slope.

Gasifying air is blown in by means of a fan not shown; one fan for both fire-boxes may be provided with a damper controlling each fire-box, or if desired one fan may be provided for each firebox.

I 2,071,678 vided in the body of the boiler, each one belonging In this example, the air is blown in through'a pipe I! provided in the wall of the hopper so as to insure its cooling and which extends throughout the greater portion of the depth of the fire-box. In any case, the length of the pipe or more exactly the length of the very narrow air exit slit i8 is "greater than the fuel feeding slots I4, in such a manner that at the front end of the slit, the thicknessof the fuel layer to be traversed by the air is considerably less than at any other point and presents a very slight resistance to the air passage.

In this way, when the fan is stopped, the air drawn in through the pipe as a result of the depression in the fire-boxes, will tend to issue through the point of least resistance. Therefore nearly all this air will issue at the end of the pipe, insuring at this point maintenance of a small pilot flame which insures immediate combustion renewal as soon as the fan is set in motion.

As shown in the drawing, a small tube 19 proceeding from the pipe and ending nearly flush with the surface of the slope, can also be provided, if desired, said tube being of course cooled is especially of interest with large air exit aperture pipes.

With this tube l9,'it is possible to avoid the necessity of providing a natural slope, which in fact can be considered as a loss in the use of the fire-box cross-section. For instancea slit H extending along the whole depth of the fire-box could be provided, the tube l9 being directed so as to have its outlet near the, upper surface of the mass of fuel, for instance at 20 (Figure 1).

The combustion chambers are provided in known manner with tapered slits or apertures 2| to insure complete combustion of gases and to realize a curtain of flames along the whole height and breadth of the combustion chamber.

Having now fully described my said invention, what I claim and desire to secure by Letters Patent, is:

1. A generating boiler including a fuel hopper, a fire box receiving the fuel from the hopper by gravity; means for admitting gasifying air to the fuel, the space in the furnace above the fire box forming a combustion chamber, means for admitting air to support the combustion of the gas within the combustion chamber, and means opening through the fuel in the fire box to provide a pilot for the ignition of the gas following interruption of the flow. of gasifying air for any purpose.

2. A gas generating boiler including afuel hopper, a fire box to receive the fuel from the hopper by gravity, means for admitting gasifying air under pressure to the fire box within the range of the fuel therein, the space above the fuel providing a combustion chamber, means for admitting air to support the combustion of the gas within the combustion chamber, and a-pipe communicating with the gasifying air conduit and extending into the fuel and terminating adjacent the'surface of the fuel for pilot light purposes.

3. A gas generating boiler comprising a central fuel-space, an offset fire box and combustion chamber divided from the fuel space, means for delivering fuel from the fuel space to the fire box, said means having a length less than the length of the fire box to cause the delivered fuel to present an area of gradually decreasing depth toward the front, means for feeding gasifying air into the fuel, and means for providing a pilot, said pilot providing means opening adjacent the surface of the fuel in its portion of decreased height.

4. A gas generating boiler including a fuel space, a combined fire box and combustion chamber, a wall separating the fuel space and combined fire box and combustion chamber, means for delivering fuel through an opening in said wall from the fuel space to the fire box, said opening being of less length than the length ofthe fire box to compel the fuel as delivered to assume a position of gradually decreasing depth from the front of the opening to the front of the combined fire box and combustion chamber, means for admitting gasifying air to the fuel box below the fuel delivery opening, and means for admitting air to the combustion chamber above the fire box.

5. A construction as defined in claim 4, wherein the means for admitting gasifying air' to the fuel of the fire box includes a conduit opening through the wall between the combustion chamber and fuel space in the form of a narrow elongated slot.

6. A construction as defined in claim 4, wherein the means for admitting gasifying air to the fire box includes a conduit communicating with a narrow elongated slot in said wall opening to the fire box, and a pilot pipe communicating with said conduit and extending substantially through the fuel in that portion of the fuel which is of decreased height.

7. A construction as defined in claim 4, wherein the heated air from the combustion chamber is directed into a tortuous path within the furnace for heating purposes.

8. A gas generating boiler including downwardly converging walls defining a fuel space, a chamber beyond each wall relative to the fuel space defining a fire box and combustion chamber, a water compartment beyond the wall, fiue pipes in said water compartment open at the upper end to the combustion chamber and at the lower end to a common outlet, an opening in each of said walls for delivering fuel from the fuel space between the walls to the respective fire boxes, a gasifying air conduit leading from the source of supply through each of said walls into the fire box, and combustion air conduits opening. into the combustion chamber and supported by a wall of the heating compartment.

9. A construction as defined in claim 8, wherein the space between the converging walls is provided with a curved bridge piece leading to the fuel openings in the walls and serving to support the fuel in the fuel space, the conduits for delivering the gasifying air to the fire boxes being supported in the space below the bridge piece.

10. A construction as defined in claim 8, wherein the combustion air conduits opening into the combustion chamber are arranged in staggered relation throughout the vertical length of the combustion chamber and are supported by a wall of the heating compartment.

J ULIEN BELLAY.

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