US1803139A - Gas producer - Google Patents

Description

April 28, 1931. $M|TH 1,803,139

GAS PRODUCER 5 Sheets-Sheet l Filed June 26, 1922 April 28, 1931.

H. F. SMITH 1,803,139

GASIRODUCER Filed June 26, 1922 5 Sheets-Sheet 2 .[HUEIJZZZI awaw Me:

April 28, 1931. s nl,803,139

' (ms PRODUCER Filed June 26, 1922 5 Sheets-Sheet 3 F I 3 I 22 252255555 i .717109172277" KWXZZ. J g g x g Z 7 i z 9 2 April 28, 1931.

H. F. SMITH GAS PRODUCER I NH-miW HM new April 28, 1931. H. F. SMITH 1,803,139

GAS PRODUCER Filed June 26, 1922 5 Sheets-Sheet 5 axda g 7 JAM} I Patented Apr. 28, 1931 PATENT o FIcE I HARRY E. SMITH, or DAYTON, onro, ASSIGNOR T terraces nnsnancn COMPANY, or DAYTON, 01110, a conronarron or oruo 7 1 GAS IEJEtODUCEB This invention relates to gas generation, and more particularly to the generation of producer gas.

One of the principal objects of the invention is to provide an improved method of gas generation, and apparatus for carrying that method into effect, in which the time of the blowing up period is materially shortened,

the character of the generated gas is improved and maintained more uniform, and the expense of operatingand maintaining the apparatus materially decreased.

' Another object of the invention is to provide a gas producer, of that character in.

whichpart of the fuel within the generating chamber functions as a lining for that chamber, with means for preventing undue lateral spread of the blast along the base of the gasproducer which supports the fuel bed.

Another object ofthe invention is to pr0- vide a producer, with a saturator located to receive heat, for vaporizing the water therein, from the active portion of the fuel bed and also from the oifgoing gases, which isso constructed that, for a given load, there is a substantially constant heat input into the saturator despite fluctuations in the relative quantities of heat input from the active zone of the fuel bed and from the off-going gases.

Another object of the invention is to provide a saturatorof this characterwhich is so constructed as to automatically vary the quantity of moisture available for saturation of the blast to accord with variations in load. Still another object of the invention is to provide a grate which is so constructed as to i remove ashes, clinker, and the like, with minimum unnecessary agitation of the fuel bed.

Generally, the object of this invention is to provide a gas producer which is so constructed as to minimize heat losses from the active zone of the fuel bed; to control the satura tion; to concentrate the blast andprevent undue lateral spread thereof, and thus eliminate wall action; to provide means for satisfactorily removing ash, clinker and the like, from the generating chamber; to thus give a producer requiring a very short blowing up period, that is onewhich is-quick starting, which is adapted to operate continuously over 1922. Serial l 1'o..570,972.

long periods of time, which during such open ation willfgenerate a gas of good quality, and which is flexible in its operation, so as to have a wide. range of'load.

Other objects and advantages of the inventionwill be apparent from the descriptionset' out below whentaken in connection with the accompanying drawing. a

As set out inthe copending. application of Harry F. Smith No. 515,861 filed November 17,1921, now Patent 1,772,642, dated August 12, 1930, it is the very general practice in the gas producer art to provide the generating chamber of thegasproducer with a heat resisting and heat insulating lining, which serves to both out down radiation losses'from the active fuel bed and to prevent the metallic shell of the producer from being unduly heated. This lining usually consists of firebrick, the lining ordinarily varying inthickness, in the producers in general use, from six to twelve inches, and at times even more. Sometimes the fire brick lining is dispensed with and a water cooled shell for the generating chamber provided. In producers as heretofore usedconimerci'ally, which generally run from three to fourteen feet in inter.- nal diameter, the ratio between the mass of incandescent fuel withinthe active fuel bed and the radiating surface of the producer shell is such that, with a lining of the kind specified,-the heatlosses, due to radiation, are comparatively so small that they occasion no serious-trouble in the-operation of the producer. g The blowing up period, though of considerable duration, perhaps as much as onehalf to three-quarters of an hour, or even more, is not objectionable sincethe producer is ordinarily brought up to-good gas making conditions before there is any appreciable demand' for'the generated gas. Andtheheat losses during operation of the producer are notsufli'cient to seriously interfere with the gas making reactions.'- Still this heat loss does affect the efficiency of the gas making reactions, and in addition affects the qualityof gas produced. For the higher the heat losses thegreaterwill-generally bethe percentage of non-combustible constituents 7 size, for example those having agratediameter of twelve inches, or less, it is found that the percentage of heat thus lost through radiation, tends to increase very rapidly as the diameter of the producer decreases. And if a producer of this small size is provided with a fire brick lining of a thickness corresponding, proportionately, to the thickness of the firebrick lining used in the conventional producer the heat losses will be so great that not only is the blowing up period unduly prolonged, but satisfactory operation of the producer is prevented. Increasing the thickness of the lining, to increase its resistance to transfer of heat therethrough, will cut down the radiation loss, and by providing a suitably thick lining the producer will function satisfactorily to make gas. However, if a firebrick lining of suflicient thickness to cut down radiation losses to a satisfactory degree is provided the heat capacity of this lining is so great that the blowing up period will be unduly prolonged. But such a small size producer will function satisfactorily if it is provided with a lining having suflicient heat insulating capabilities and also having small heat capacity.

A type of producer having a lining of this character is shown in the copending application of Harry F. Smith Serial No.'398,749 filed July 24, 1920. The producer disclosed in that copending application has a lining consisting of a thin inner layer of fire brick, of small heat capacity, backed by a comparatively thick layer of heat insulating material. Such a producer, with a grate of less than six inches diameter, operating upon charcoal, and starting cold, can be brought up to good gas making condition within fifteen minutes, and often in five minutes. But where the gas generated is to operate a gas engine, such as the engine forming the power unit of the well known types of-individual house lighting plants, it is especially desirable that the blowing up period be very brief, and that the producer quickly come up to approximately maximum gas making conditions' For the mixing valve, or carburetin-g device, which'controls the air and gas mixture fed to the engine cannot be set for most eflicient operation until the gas becomes of approximately uniform character.

But where the conventional type of lining is dispensed with and the entire generating chamber is filled with carbonaceous material, such as charcoal, coke or the like, the blast being so controlled that the active zone of 1 the fuel bed is at all times surrounded by a layer of inactive fuel which serves to prevent transfer of heat from the incandescent or active zone of the fuel bed to the shell of the producer and radiation from the shell into the surrounding atmosphere, the blowing up or starting period may be greatly decreased, and it is quite exceptional when a starting period of as much as five minutes is required. In fact combustible gas has been secured, operating upon charcoal, with a producer of this general character, within thirty seconds from the time of first igniting some kindling, such as a newspaper, in the ash pit, and an engine operating upon the gas generated in such a producer has been caused to develop approximately maximum power within less than five minutes.

The producer forming the subject matter of this particular invention is quite similar in certain of its underlying fundamentals of construction and in certain of its constructional details to the producers forming the subject matter of the above referred to copending applications; but because of certain features of construction which are incorporated therein, and which are not incorporated in the producer disclosed in the said copending applications, this particular producer is adapted to give more satisfactory operation where it is operated continuously over an extended period of time, and will 'also generate a better average character of gas over such a continuous period of operation.

The features of construction of the producer embodying this invention are shown in the accompanying drawing, in which like characters of reference designate like parts throughout the several. views thereof:

Fig. 1 is a plan-view of a power plant comprising, generally, a producer, a purifier, a gas engine constructed to operate upon the gas generated within the producer, and at the same time to furnish the suction for causing the generation of such gas;

Fig. 2 is a sectional view along the line 22 of Fig. 1;

Fig. 3 is an enlarged sectional view through the base of the producer shown in Fig. 1, the view being along the line 33 of Fig. 1

looking in the direction of the arrows;

Fig. 4 is a sectional View, along another I plane, through the base of the producer, this view being along the line 44 of Fig. 1;

Fig. 5 is a view partly in vertical section through the blower, and cooperating valve and switch mechanism, which is used in starting up the producer;

Fig. 6 is another view of the blower, valve and switch, this view being also partly in section, the section being along a line at right angles to the plane of the section of Fig. 5;

Fig. 7is averticalsection through a prollt ducer having a somewhat modified form of base construction I Fig. 8 is a sectional view through the base of the modification shown in Fig. 7, the view being at substantially right angles to the plane of Fig. 7

Fig. 9 is a vertical sectional view through still another modified form of producer;

Fig. 10 is a plan view ofthe base section of of the the producer shown in Fig. 9; n Fig. 11 is a plan view of the base rorm of producer shown'in Figs. 1-4;

Fig. 12 is a horizontal sectional view showing certain details of construction of the purifier; and I Fig. 13 is a detail View, in the nature of a plan View, of the scraper forming one element of the purifier.

As shown in Figs. 1 and 2 the producer constitutesone element of a power plant, but of course it need not necessarily be used as an element in such a system, for it maybe used to supply gas for any desired use, as by way of illustration, for industrial heating operations, such as heat treating, drop forging and the like, or for domestic purposes such as the cooking of food, the heating of water, the heating of the rooms of a house, lighting, and the like. But as illustrating a preferred embodiment of the invention it is shown in connection with a gas engine having a generator direct connected thereto and serving to supply electric current for domestic use. p

The producer, forming a part of'the plant disclosed in Figs. 1 and 2, is designated generally by the numeral 20 and comprises a metallic shell 21 and a base portion 22. The nietallic shell 21 is preferably of sheet metal, the thickness of which varies according-to the size of the producer; but inasmuch as this shell, in the type of producer shown herein,

has to sustain little or no weight other than the weight of the shell itself it may be made of comparatively light material, In producers of the small size adaptedfor serving as a unit in a power plant for domestic house lighting purposes, in which the producer shell may have an over all diameter of 20 to 24 inches and an over all height of 24 to 36 inches, a shell made of inch sheet steel has been found to function very satisfactorily. The upper end of the shell is closed by means of a top 23, which is shown as welded in place,

26 is substantially hemispl erical in shape and a correspondingly shaped bail is provided the ends of which are bent to form loops or eyes which engageupon suitable. lugs carried by the'members 28, which are in turn secured to the top 23-by some suitable means, such for instance as the bolts 29. The bail when positioned on the lugs is thus capable of free movement into or out of engagement with the cover 26 to release that coverso that itmay be readily removed or to hold it in gas-tight contact with the flange 25. A stop 30 is carried by the cover 26 to limit movement of the bail. The cover is provided with a machined surface which is constructed to make a tight joint with the flange 25. If desired the cover may have a groove therein for receiving the flange 25, suitable packingbeing provided in this groove to make a tight joint.

The other. end of the metallic shell 21 is open and is adapted to seat upon the base member 22, which is provided with a peripheral groove 32, adapted to receive the free cooperating end of the metallic shell 21, suitable packing material 33 being positioned therein, so that when the shell and base member are drawn tightly together leakage between these two members is prevented. The

shell, adjacent its freeend is provided with outstanding projections 34 each having a passage therein, adapted for alignment with the cooperating passages in the extensions 35 of the base member. A- plurality of legs 36 are provided, for supporting the assembled shell and base member, each of these legs having a threaded extension 37, constructed for posi tioning'within the aligned passages in the members 34 and 35, and to receive a nut 38, proper turning of the nuts 38 resulting" in drawing the shell and base member firmly together to hold them rigidly in assembled position, and to, at the-same time, hold the supporting legs 36 firmly in position. An upstandingfiange 39 is provided upon the base member, which extends a short distance upwardly'into the shell 21 when the device is in assembled position, to hold the shell and base member against lateral movement relative to each other, to thus maintain the shell properly centered.

The base member 22, when the producer is assembled and in operation, sustains the fuel bed which is contained within the shell '21. This base member is provided centrally with an opening 40 which is surrounded by an upstanding flange ll, which extends upwardly to'a height at least as great as the hhight of the peripherally arranged flange 39, a trough or pocket being thus formed within the base member between these two flanges." During operation this trough contains a layer of heat insulating material, preferably a layer of material consisting of some of the finely dividedcarbonaoeous material which is being used as fuel and which is considerably more finely divided than the bulk of the fuel comprising the fuel bed. Where the producer is operating upon charcoal, for example, this p istics of fusing which results in clinker fori the making reactions to take o'iftalze.

mation, and in addition is always available.

' The purpose of this layer of heat insulating material is to-heat insulate the base member from the active zone of the fuel within the shell 21. The opening 40 serves as a blast port, or tuyere, opening into the generating chamber, the blast, which preferably consists of air containing a quantity of moisture, being introduced therethrough into the fuel bed to maintain the active zone of the fuel bed in a state of incandescence, and to cause place. A grate 43, is positioned within the opening 40, which grate is carried by a rotatable shaft 44, which is in turn mounted within a standard supported upon the bottom of the ash pit 46 of the base member. This grate is preferably in the form of a spiral or worm, and its constructionis such that when the shaft 44 is rotated ashes, clinker, and the like, will be forced downwardly into the ash pit. This grate serves to support the greater part of the active Zone of the fuel bed, the blast of air and moisture which is introduced through the port 40 being so controlled as to pass only through the central portion of the fuel bed, thus leaving a zone of inactive fuel about this central or active portion of the fuel bed which serves to heat insulate the active zone of the fuel bed from the metallic shell and to thus prevent heat losses from the incandescent fuel to the atmosphere.

The desired control of the blast is secured,

primarily, by properly positioning the gas The producer of course may be either pressure operated or suction operated, but in ei her case the blast as it passes'through the fuel bed will follow the path of least resistance. With a fuel bed of substantially uniform resistance to'draft therethrough, this path of least resistance will normally be the shortestdistance between the point of blast inlet, which is the opening 40, and the point of outlet which is the offtake pipe. In order to secure the desired control of the blast there- .fore. the producer is provided with a central oiftake pipe 50, and as a result of this construction the blast, as it passes through the fuel-bed will tend to maintain theactive zone of the fuel bed of substantially barrel shape as shown in Fig. 2. Of course the later spread of the active zone of fuel will be direct- 1y dependent upon the quantity of blast passing therethrough; that is, upon the load. Tim at all times the blast, regardless of its is thus secured.

Obviously if the blast did not tend to spread laterally through the fuel bed after passing out of the opening 40 the entire active zone of the fuel bed would be supported upon the grate 43, but as stated, in actual practice the blast does tend to spread laterally. WVhile the grate 48 directly supports the major portion of the active zone of. the fuel bed,.therefore, nevertheless, the active zone of the fuel bed does, in operation, extend laterally a considerable distance so as to considerably overhang the grate 48. One reason for providing the layer of heat insulating material 42 is to prevent heat transfer from the overhanging portion of the active zone of the fuel bed directly into the base member. t is also found, Where the layer of heat insulating material 42 is dispensed with and the fuel bed rests directly upon the metallic surface of the base member 22, or upon such a ring of heat insulating material as is shown in the producer described in my copending application 515,861, that there is a tendency for Wall action to develop. That is to say, because of the fuel resting upon a solid or rigid and comparatively smooth surface the resistance to the travel of the blast along that surface is somewhat less than the resistance to the travel of the blast through the fuel bed itself. Therefore there is a tendency, with such a construction, for the blast to travel laterally an excessive distance, and it has even happened that this spread due to wall action has been such as to extend the active zone of the fuel bed into contact with the shell 21. This condition, which would not normally be present but which might sometimes occur with the producer operating under extremely heavy load, is particularly undesirable and the layer of finely divided heat insulating material 42 effectually prevents it. Where a layer of finely divided material of the character specified is used a path of less resistance to the travel of the blast does not exist, for the fuel imbeds itself in the materialof the layer 42 and the resistance to fiow of the blast is, if anything, greater than through the fuel bed itself.

'lVhen operation of the producer is started, a layer of material 42 should be placed in thetrough of the base member, but during operation of the producer this layer is automatically renewed, for the fine fuel tends to Work down and collect upon the base member, and to assume a definite angle of repose; and there is, thus, little or no tendency for the finely divided fuel adjacent the base member to pass through the opening 40, or to be consumed during the gas making reactions.

' If the blast were so controlled as to prevent lateral spread and to thus so localize the acive zone of the fuel bed that it would notspread laterally beyond the periphery. of the grate the problem of ash removalwould be comparatively simple. But in actual practice it does thus overhang the grate and the grate is, therefore, provided with a scraper member 47, which as shown most clearly in Fig. 11, is curved, the arrangement being such that as the grate is rotated, in the direction of the arrow in Fig. 11', any ash surrounding the upstanding flange et1-will be moved toward the center of the producer and will fall through the opening 40 into the ash pit. Where the conventional fire brick lining is dispensed with, and the layer 42 con'- sists of finely divided fuel, the tendency to form clinker during gas generation is considerably decreased, but nevertheless in the operation some clinker may be formed. 1 Any such clinker will gradually work down through the active zone of the fuel bed as the fuel is consumed, into the path of the scraper 47 and will, along with ashes, be moved toward the center of the producer, on to the spiral grate which will feed it down wardly through the opening 40 intothe ash pit. As is most clearly shown in Fig. 2, the outer 'end of the scraper 47 is upturned at an angle which substantially corresponds with the boundary of the active zone of the fuel bed. As shown this angle is substantially 45, but of course with different fuels and with different'sizes of producers this angle might be different, and no definite angle of inclination for the upturned portion of the scraper may be fixed upon, therefore, but it should be given such inclination as corresponds with the particular type of producer with which it is used. In order to remove all the ash which is formed the scraper'must extend laterally the distanceof the greatest lateral extent of the active zone of the fuel bed. The active zone. of the fuel bed, however, as set out above, is somewhat barrel shaped so that its greatest lateral extent is substantially midway the grate and the gas offtake 50. If the scraper is made fiat, therefore, it will during operation tend to move toward the center of the producer finely divided fuel which is accumulated near the base but which has not been at any time a part of the active zone of the fuel bed and will thus decrease the resistance to flow of the blast with resulting lateral spread of the blast through this part of the fuel bed. By upturning the end of the scraper at an angle corresponding with the outer boundary of the active zone of the fuel bed this condition is avoided and only ash is removed.

As stated above a blast of air and moisture erated theblast will be forced through the opening 40 into the fuel bed under pressure. But the producer is preferably suction operated, the gas engine forming a part of the power plant being connected to the generating chamber of the producer; which furnishes gas for operating the engine, the engine in turn furnishing the suction for operating the producer. In the construction shown the base member is provided with a second passage, or chamber, 60, which is positioned above the offtake passage 52, the two passages being separated by means of a par tition 61, the construction being such that as the hot gas passes off from the generating.

chamber through the pipe 51, and offtake passage 52 it will flow over the partition 61 and heat that partition. As shown, particularly in Fig. 4 the partition 61 is somewhat inclined toward one side, and is provided with a pocket or depression 62 at one extreme side, into which opens the water supply pipe 63 the other end of which opens into the vessel'64 of the water feed. This vessel is of a generally conical shape, and is adapted to receive and support a'bottle or other container 65 which is first filled with water and then placed in inverted position with its open end within the vessel 64 and at a height corresponding to the desired level of the water within the vaporizer chamber or passage 60. As shown the pipe 63is provided with an elbow 66, the two sections of the pipe being arranged at substantially right angles to each other and the construction being such that the two sect-ions of pipe may be moved relative to each other toraise or lower the vessel 64, and the bottle65 associated therewith, to correspondingly raise or lower the level of the water within the vaporizer 60. In order to effect this variation in the water level within the vaporizer the base member is provided with'a lug 67, having a passage therein within which is positioned a bolt 68 having a hook or loop at the lower end surrounding the pipe 63, the upper end being threaded and having suitable adjusting nuts 69, the construction being such that by proper manipulation of the adjusting nuts 69 the pipe 63 may be raised or lowered to cause corresponding raising or lowering in.

maintained substantially constant. The construction described just above is adapted to accomplish this desired control. As the heated gases pass off through the oiftake passage 52 they-heat the partition 61,'which in turn heats the water within the vaporizer causing it to give off vapor which is taken up by the incoming air which enters through the opening 7 0, passes over the surface of the water within the vaporizer 60, taking up moisture as it does so, and then passes into the ash pit through the opening 71, whence it passes upwardly into the fuel bed. Obviously more gas will pass through the passage 52 under-heavy load than under light load, and therefore more heat will be transferred into the water within the vaporizer under heavy load than under light load. But at the same time more air is required under heavy load than under light load, and the proportions of air and moisture thus tend to remain the same under varying loads. But in addition, the level of the water within the vapor izer is partly dependent upon the load upon the producer, for at heavy load there is greater suction upon the vaporizer and therefore greater tendency towards the formation of vacuum than is the case under lower load; and therefore with increasing or decreasing load the level of the water within the vaporizer will rise or fall to cover a greater or less portion of the inclined partition 61 and to at the same time expose a greater or less surface to the air passing through the vaporizer. If, for example, the

load should suddenly be increased, therefore, the suction through the vaporizer would correspondingly increase and the level of the water therein would rise. This extra water would spread out over a part of the partition 61 which had not been theretofore in contact with water and the important result would be the rapid generation of moisture, to give at once the necessary excess of moisture needed for the immediate excess of air drawn in. Then as a greater quantity of heated gas passes through the offtake passage 52 the temperature of the entire quantity of water within the vaporizer will be raised sufii ciently to generate the necessary quantity of moisture and thus give the desired proportion of moisture to air.

Preferably a plurality of baffles or partitions 72 are provided which are so arranged that as the air passes through the vaporizer it is maintained in contact with the water for a greater length of time and ample opportunity for absorbing of moisture afforded. As shown, particularly in Fig. i, the vaporizer is provided with a second port 73 corresponding to theport 70, the base member being provided with a plate 7 1, having an opening 7 5 therein which registers with the port 7 0 to admit air, the remainder of the plate serving to close the port 73 except when the plate 7'4 is removed. This opening 73 permits access to the vaporize-r so that itmay be cleaned out. The offtake passage 52 is also provided with a clean-out port closed tal position, with the upper edge of the door contacting with its seat to hold it open, to permit free access to the ash pit. The door having been placed in this open position may he closed by lifting up on the handle 82 to swing the door entirely clear of its seat and then dropping the handle when the door will i assume a vertical position to close the ash pit. The construction results from pivoting the door as shown with the axis pivot above the center line of the door and offset from the general plane of the door.

The rotatable shaft 44, upon which the grate is carried, is provided with an operating handle which as shown preferably consists of an elbow portion 85 having four radially arranged handles 86, spaced equal distances apart, by means of which a suitable rotation of the grate may be secured.

As set .out above the producer is directly connected to a gas engine, the producer furnishing gas for operating the engine, the engine in turn during its operation furnishing the suction for operating the producer. The ofi'take pipe 53, therefore, is connected to the inlet pipe of the gas engine, but because of the presence of impurities, such as tar and the like, in the gas, which would tend to foul the working members of the engine and interfere with its efficient operation, purifying apparatus of some sort, within which the gas may be treated to remove impurities therefrom, is generally necessary in power plants of this character. As shown, generally, in Fig. 1, the offtake pipe opens into a purifier or separator which is designated generally by the numeral 100.

This purifier consists of a cylindrical shell or drum 101, the open upper end of which is, during operation, closed by means of a cover or top 102. The shell 101, and the top 102 are preferably made of thin sheet metal, which may be of substantially the same gauge as that'used in making the shell 21 of theproducer or of somewhat lighter gauge, and the upper free edge of the drum 101 is rolled or beaded as shown at 103, to provide a seat for the top, suitable packing 104 being interposed between the top and the seat 103, to prevent leakage. The top is preferably provided with a plurality of depending guides 106 which extend down into the shelllOl to is e properly center the top when it is in position. Intermediate its ends, and preferably substantially midway of its height, the shell 101 is provided with a transverse partition 105, which divides it into two chambers and upper 107 being adapted to house the purifying mechanism while the lower 108 acts as an equalizer to prevent undue pulsations in the gas passing through the purifying chamber 107, as a result of the operation of the gas engine.

The partition 105 is provided with a substantially central opening therein, and a hollow fitting 110, which is secured to the partition 105 in any desired manner, surrounds this opening, the upper end of this fitting being cone shaped to receive a correspondingly conical shaped opening in the member 111 which serves to support the purifying material through which the gas, entering the chamber 107 from the producer passes on its way to the engine. This member 111 preferably consistsof apan shaped member, having upstanding side walls 112, and a somewhat oval false bottom 113. The false bottom 113, as shown particularly in Figs. 2 and 12 is provided on its upper face with a plurality of concentric grooves 114: and is also provided with a plurality of radially arranged slots or passages 115. This false bottom has positioned upon its uppersurface a layer of fabric 117, which is preferably a good grade of flannel, or the like, such as the wool filter cloth which is an article of commercial use. This cloth is covered with a layer of finely divided purifying material 118, which material is preferably of the same character as the fuel used in the producer. If the producer is operating upon charcoal the layer of purifying material 118 will consist of finely divided charcoal or charcoal dust. If the producer is operating upon coke this layer will consist of coke dust or breeze. The primary purpose of the cloth 117 is to provide a support for the finely divided purifying material which permits the ready passage of the gas therethrough, but prevents any of the finely divided puri fying material being carried along with that gas. The filter cloth is preferably stretched smoothly and somewhat tightly over the false bottom 113, any desired means being used for retaining this cloth in position and properly stretched. Preferably, however, the cloth is retained in position by means of a piece of rope 120 which is pressed down into a suitable groove 121, within thememher 111, the proportions of the groove being such that as the rope is pressed into position it will draw the cloth tight, and. will remain in position holding the cloth properly stretched. If desired a spring, such as is disclosed in the above referred to applicaions may be utilized for this purpose but experience has shown that a piece of rope is just as satisfactory and'considerably cheaper and less difficult to assemble.

The gas introduced into the chamber 107, through the offtake pipe 53, passes downward 1y through the layer of purifying material,

the layer of cloth 117, and thence through the passages 115 in the false bottom, impurities being removed as it passes through the purifying material, the purified gas passing through the member into the chamber 108 and thence outwardly through the pipe 123, which is connected to the inlet pipe 124 of the gas engine 122.

As the engine 122 operates pulsations will be setup in the 'pipe'123 which have a tendency to agitate the purifying material 118 and interfere with its effectiveness of operation and in order to prevent this a chamber 108 is provided which chamber acts somewhat in the nature of an equalizer to absorb these pulsations and prevent .them from affecting the purifying material 118.

The function of the concentric grooves 114: is to prevent localization of the gas into streams as it passes through the layer of purifying material, as wouldbe the case if the upper surface of the false bottom 113 were smooth and the passages were as widely separated as shown. But by providing these concentric grooves the gas is free to pass through substantially the whole area of the layer of purifying material and after it passes therethrough can travel through the various grooves to the passages 115.

The false bottom 113, as shown, is preferably oval shaped, since such construction permits of maintaining the layer of fabric 117 snugly in contact with the false bottom 113 throughout its extent. If this layer of fabric does not lie snugly against the false bottom 113 it will tend to vibrate or oscillate during operation of theapparatus and thus disturb the layer of purifying material, the effect being so pronounced at times as to break the continuity of this layer of purifying material thus allowing some of the gas to pass through without being subjected to purifying action. I

- Because offthe character of the layer of purifying material the presence of considerable quantities of water or-other liquid rm purities within the gaswill tend to destroy its effectiveness. Water carried by the gas 7 will be removed therefrom, along with other impurities, as the gas passes through the purifier and this water will tend to clog up the purifier. In'order to prevent this a condenser is interposed within the delivery pipe 53, between the purifier and the producer. As shown this condenser preferably consists of several extra lengths of pipe 130, but of course any other desired type of condenser may be used.

Inasmuch as the impurities which are removed in the purifier are deposited on the,

upper surface of the layer of material 118 the tendency during operation is for these impurities to form a layer or crust over the top surface of the purifying material to clog up the passages therethrough and destroy the effectiveness of the purifier. In general practice the layer 118 is formed by placing a quantity of the purifying material to be used upon the false bottom 113, sufficient of this material being used to form a layer whose upper surface is substantially level with the upper edge of the flange 112. Impurities deposited upon this layer of purifying material will tend to build up itsthi'ckness; If this layer of material is removed the original purifying material will be found to have its original effectiveness. In order to permit removal of this layer of material a scraper, which consists of a curved blade 135, to which is attached a rake member 136, is mounted upon the lower end of the rotatable shaft 137, which is positioned within an opening in the top 102, a suitable enlargement or handle 138 being provided, upon the outside of the top, to permit ready manipulation of the scraper. The handle 138 is preferably substantially round with a depending flange 139 which contacts with the upper surface of the top and tends to prevent leakage through the opening in which the shaft 137 is mounted. A suitable spring 140 is positioned between the inner face of the top 102 and a disc 141 carried by the shaft 137, to hold the flange 139 against the top, while at the same time permitting ready rotation of the shaft 137 and the scraper member carried thereby. The blade 135, as shown particularly in Fig. 2 rests upon the upper surface of the flange 112 and as this blade is rotated it tends, because of its curvature, to scrape off any excess material and force it over the edge of the flange.

Sometimes the material deposited upon the layer 118 tends to cake but the rake member 136, which consists of a wooden bar having a plurality of teeth 143 imbedded therein, will break up this coating, as the shaft 137 is rotated, to thus restore the cleaning effectiveness of the apparatus.

Details of construction of tie engine 122 are not shown since this engine may be of any desired type. The particular engine shown is an engine of the character shown herein, details of construction of which are shown in the patent to Charles F. Kettering and VVilliam A. Chryst, No. 1,341,327 dated May 25, 1920. However, any other type of engine which is adapted to operate upon producer gas may be used. As stated above during operation the purified ga s passes from the chamber 108 into the pipe 123 which is connected to the inlet pipe 124, of the engine, and the exhaust gas resulting from the combustion of this gas within the cylinder of the engine passes outwardly through the exhaust pipe 145, into the vent pipe 146, which is connected to the atmosphere.

While the engine 122 during operation furnishes suction for blasting the fuel bed to cause the generation of gas within the producer, in a plant of this character a starting blower is ordinarily provided so that the producer may be blasted during the starting or blowing up period, to bring it up to good gas making conditions or until a gas is generated which is of a proper quality for operation of the engine. As shown this blower, which is designated generally by the numeral 150 is of the conventional centrifugal type, operated by a suitable motor 151, the inlet 152, of the blower, being connected to the ofitake pipe by means of a branch pipe 153, the motor pref erably being positioned between the producer and the purifier, thus lessening the load on the motor during its operation, although it will function very satisfactorily if it is positioned beyond the purifier. The outlet pipe of the blower, 154 is connected to the vent pipe 146, the gas generated during the opera tion of the blower being vented to the atmosphere through this pipe. The housing for the blower has attached thereto a three-way valve fitting 155, one port 156 of this fitting being connected to the pipe 153, another port 157 being connected to the pipe 158 which opens into the chamber 107 of the purifier, the third port being the inlet port 152 of the pump housing. Positioned within this fitting is a rotatable valve 160, which, as shown particularly in Fig. 6 is provided with a passage or groove 161, the construction of the valve being such that when in one position the pipe 153 is connected to the pipe 158, while the inlet port 152 of the pump housing is entirely disconnected from either the pipe 153 or the pipe 158 which position is shown in Fig. 6;

while in another position the pipe 153 and the inlet port 152 are connected and the pipe 158 is entirely disconnected from either. In starting, and during such time as the blower is operating the valve 160 is positioned to connect the pipe 153 and the inletport 152, in which position the gas drawn off through the oiftake pipe may be vented to the atmosphere through the pipe 154 and the vent pipe 146. As soon as the gas becomes of suitable quality, which may be determined by igniting the small jet of gas that escapes through the pipe 165, which pipe opens into the offtake 154 of the pump, the blower is stopped and the valve 160 positioned to connect the pipe to the pipe 158. The engine 122 is then started and the suction of the engine causes blasting of the fuel bed and draws the generated gas through the purifying system to the combustion chamber of the engine. The engine is preferably provided with an'electrical starting system, but this of course is not essential since the engine can be started by hand.

The valve is preferably'provided with me ee suitable means for holding the blank part thereof tightly against its seat to prevent.

leakage therethrough. Obviously when the pipe 153 is connected either to the inlet 152 of the pump or to the pipe 158 it is a matter of indifference if there is some slight leakage around the valve from the pipe 153 into which ever of these two ports the pipe is connected.

to; but it is undesirable to have leakage around the valve into or from that one of within suitable sockets in the valve plug, the

members 167 contacting with the valve casing to force the blank portion 166' of the valve ti htly against its seat.

The valve 160 preferably has associated therewith a switch for controlling the motor 151, the construction being such that the motor is automatically started to operate the blower when the valve 160 is positioned to connect the pipe 153 with the inlet port 152 of the pump and is automatically stopped when the valve is moved into position to connect the pipe 153 to the pipe 158. This switch consists of a plate 170, of insulating material, suitably connected to the valve fitting, which plate carries two contacting members 171 and 172, one of which is connected, through a suitable conductor, to one terminal of a battery, or other suitable source of electrical potential, the other being connected, through the conductor 173 to one terminal of the motor 151 the other terminal of the motor being connected through the conductor 174 to the other terminal of the battery, or other source of electricalpotentialQ The handle 175, for operating the valve 160 has attached thereto a strip 176 of con ducting material which is suitably insulated from the said handle, the construction of this strip, and the relative positioning of the handle with respect to the valve, being such that when the valve is turned to connect the pipe 153 to the port 152 the strip 176 will be so positioned as to contact with each of the contact tioned as to not connect the two contact mem-' bers 171 and 172, the motor circult thus being broken. In Fig. 2 the valve handle 175 is shown positioned with the strip'176' out of contact with the contact members 171 and 172, and with the motor circuit-thus open. This is the position which corresponds with the positioning of the valve shown in Fig. 6.

The engine 122 may be provided with any suitable formof mixture regulating device. The engine is normally provided with a sim ple mixing valve which is adapted to mix the fuel and air in proper proportions. It may of course be provided with a conventional form of carburetor. This mixing valve is indicated diagrammatically at 180. It has been found'in operation that'an engine of the character shown herein, which is designed for operationupon a liquid fuel such as kerosene or gasoline, when operating upon'producer gas will give improved operating results if the inlet pipe is provided with a port permitting theintroduction' of some air into the gaseous fuel before it passes into the mixing valve for admixture with more air to give the properproportions for the desired combustible mixture. In other words instead of depending entirely upon the mixing valve to give the desired combustible mixture theinlet pipe is provided with a fixed opening through which atmospheric air is drawn in under the suction of the engine and the mixing valve operatesto admit a supply of air additional to this preliminary mixture of air and gas the quantity of air being easily con trolled to give any desired combustible mixture. As shown this opening in the inlet pipe through which preliminary air is admitted is provided with a short section of pipe 181, but this section of pipe may be dispensed with if desired. V

In Figs. 7 and 8 is shown a slightly modified form of producer. This producer comprises a metallic shell 200, which issubstan tially identical in construction with the shell heretofore described. Butthe base member, in thismodification, is of somewhat different construction from the base member 22. This base member preferably consists of an upper section 201 and a lower section 202. The up- 7 pivotally connected to an operating lever 208 mounted upon the rock shaft 209 which may be operated, in any suitable fashion, from' outside the producer.

The lower part 202 of'tlieibase incloses an ash pit 210, provided with a suitable door 211, which is pivotally mounted so thatIit may be readily opened, the construction be-' ing such that whenever released the door will. fall into closed position- Theupper section201 ofthe base is provided with a flange. or partition 215 which extends outwardly from, and is 'carried'by the free 'edgeof this 'depending'portion of. this flange will contact with a cooperating upjstandingflange220 on the lower member 202, to form a tight joint therewith. The upper member 201 of the base is also'pro- V vided with a depending flange 221, substantially concentric with the flange 216, which flange is also 'so constructed that when the base member is'in assembled position it will contact with the "cooperating upstanding flange or rib 222, on the lower base member. It is'obvious from this construction that, when the two sections of the base member'are in assembled position the upper wall 219 of the b'ase"me1nber202,'the partition 215, the depending portion of the flange 216, the depending flange 221 and therespectively cooperating ribs or flanges 220 and 222 carried by the member 202 of the base will form a closed circular passage 223. The base member 201 has a verticall'y arranged passage 225 therein, the lower end 'of'whi'ch opens into the passage 223 and the upper end of which receives the pipe 226, which extends upwardly into the shell 2000f the producer, and carries upon its upper end the central draft tube 227,- through 'which the generated gas 'pas'ses'ofl' from the generating chamber "of the producer. The member 202 of the base isprovidedwith a passage 228 one endof which opensinto the passage 223 and the other end of which receives the delivery pipe 53. By "means of this construction the generated gas passes through the draft tube 227, the passage 223 and the delivery pipe53', to any desired place of use or storage. 7

The upper section 201 of the base is also provided 'with a depending flange 230, which is'c'oncentrio with and substantially the same diameter-"as the flange 216, a suitable ring or band 231 being so positioned that it cooperates with the dependingflange 230 and the upstandingportion of the flange 216 to inclo'se'a passage or chamber 232 which is coaxial with the passage 223 and is separated therefrom by means of the partition 215. Of course the ring 231 could be dispensed with if desired and the depending flange 230 and the upstanding portion of the flange 216 cast integral.

member 201, extends into "the cavity within he. construction shown is'de'slrable, however, because of 1ts greater rece es the member 201 and connectsthe passage 232 with the cavity inside the base. And inasmuch as the base member, when the device is assembled, supports the shell 200 and also water is maintained within the passage 232,

the hot generated gases passing through the passage 223 heating up the partition 215 and the cooperating metallic members of the base,

these in turn heating the water within the passage 232 to cause the generation of vapor which is taken up by the ingoing air of the blast as it passes through this passage to the generating chamber of the producer. A proper Water supply is maintained by means of the same general type of fuel feed as is described above. For purposes of easy description this type of fuel feed is designated as a chicken feed type,'and consists essentially of a-pipe 237, one end of which opens into the passage 232 and the other end into a funnel-shaped member238 which is adapted to receive and support the bottle or container 239, which is shown as preferably constructed of metal, though it may be a glass the positioning of the outlet of the container 7 4 239. As the water level falls below that air will move up into the container and Water flows therefrom to bring the level in the passage 232, which is for purposes of easy description designated asa vaporizer or saturator,-up to the desired level.

During operation a layer of ashes-is-at all times maintained on the grates, and Within the cavity in the producer base member, which serves to heat insulate the active zone of the fuel bed from the base member, and thus cuts down the heat'losses which would otherwi'seresult from transfer of heat from the active fuel into the base member and radiation therefrom into the atmosphere.

' Of course, in practice the thickness of this dina'ri-lyconditions will be such that the layer of ash will extend approximately up to the level of the blast inlet pipe 236, the blast thus being introduced into the lower level of the active fuel bed. But as the ash may not be shaken down over a period of several hours its general level may vary materially.

The producer'is preferably supported upon suitable legs 241 which as shown have threaded sockets in the upper ends thereof adapted to receive extensions 'orbolts 242 which are tical in construction with the shell 21 de-' scribed above. The base member is also quite similar to the base member described above in connection with the modification shown in Figs. 1 and 2, this base member being provided with substantially the same means for holding it in assembled position with the shell, and with the same type of leg construction as already described. This base member is also provided with an upstanding flange 301,- positioned about a central opening 302, a concentric upstanding flange 303 being positioned intermediate this flange 301 and the peripheral flange 30% which serves to center the shell 300. The trough or depression between the two flanges 301 and 303 is adapted to contain a layer of finely divided heat insulating material of the character heretofore described. This trough is also provided with a series of curved partitions 310, which are shown most clearly in Fig. 10, which partitions divide the circular trough between the flanges 301 and 303 into a plurality of pockets. The ash pit 311 is provided with an upstanding standard 312 within which is rotatably mounted a shaft 313, which extends, coaxially, upthrough the opening 302 and carries a flat'perforated grate 31 1 upon the upper end thereof. Ashes resulting from the combustion of that portion of the active zone of the fuel bed which is directly supported upon the grate will pass downwardly through the perforations in the grate into the ash pit. But as described above the active zone of the fuel bed spreads laterally and overhangs the grate, ashes and clinker thus working down around the grate. in order to re move this ash the grate is provided with two scrapers or vanes one of which, 315, is

longer than the other, 316, each scraper being curved, so that upon rotationof the grate in the direction indicated by the arrow in in Fig. 10 ashes will be moved toward the opening 302 and caused to pass downwardly into the ash pit. By making one of these scrapers longer than the other more desirable results are secured, for where both are made of the same length the ash tends to pack as it is crowded toward the central opening so as to cause jamming of the grate and prevent ready rotation and removal of the ashes. But making one scraper longer than the other this condition isavoided, the shorter scraper tending to handle the ash in the inner zones and the longer scraper the ash in the outer zones.

While the producer of the character described, in which no lining isused, is comparatively free from formation of clinker there will be at times some clinker formation. If these clinkers are of substantial size they-obviously cannotpass downward ly through the perforated grate when they are moved on to that grate through the operation of the scrapers. But, during operation, as the grate is rotated any clinkerswhich are formed will be moved by the scrapers into contact with the partitions 310 and crushed or ground into such small size that they will readily pass through the grate.

Means for providing saturation, is quite similar to the means described above in connection with Figs. 1 and 2. The base, around the ash pit is provided with a partition 320 which-divides that portion of the base into a lower passage 321, to which is connected the pipe 322 through which-the hot gases pass downwardly into this passage, and thence outwardly to any desired place of use or storage through the offtake pipe 53". The upper of these two passages or chambers 325 serves as a vaporizer or saturator, Water being introduced thereinto through a chicken feed mechanism, designated generally by the numeral as provided with a fuel feed, which may be of any conventional and suitable, construction; but which is preferably of the charac-' ter described in the above referred to copending application of Harry F. Smith No. 515,861, filed November 17, 1921, now Patent 1,772,642, dated August 12, 1930. By using such a fuel feeder continuous operation of the producer may be secured. The other forms of producers as shown in Figs. 1 and 2, and in Figs. 7 and 8, are provided with a cover for the fuel supply opening instead of a fuel feeder, but each form is adapted to receive a fuel feeder, if desired, so that continuous operation, without the necessity of any shut. down for the introduction of new fuel, may be obtained.

Because of the construction described above, in which the ordinary lining for the producer is dispensed with, the blast being so controlledthat the active zone of the fuel heat insulate the active zone of the fuel bed from the metallic shell of the producer, and

also because of the base construction in which the active zone of the fuel bed is at all times heat insulated from the base ofthe producer bymeans of a layer of suitable heat insulating material, and because of the grate constructionin which that portion of thegrate which is in direct contact with the active zone of the fuel bed is supported upon a single small shaft, so that the portion of the grate which is in direct contact with the active portion of the fuel bed is entirely out of direct thermal contact with the base of the producer, and the sole path of heat conductance from the grate is throughthe single supporting shaft, loss of heat from the active zone of the fuel bed by radiation from the shell and 3 base of the producer into the surrounding atmosphere is substantially prevented.

Fur-

thermore since the blast is free to choose the path of least resistance and as it passes throu 'h the fuel bed is at all times in contact ,with chemically active material, the starting period is greatly decreased. Also because of this construction heat losses during operation are minimized and therefore a gas of high heat value is obtained, for generally, the

, greaterthe heat losses the greater the percentage of non-combustible within the gas.

Furthermore this construct-ion lends itself to the eliminationof, wall action along the lining, and this in turn results in a concentration of the blast. And of course concentration of the blast means better gas making conditions, and quicker starting. Again the producer is so constructed that the saturator or vaporizer receives heat by direct conduction from the active zone of-the fuel bed, throughthe layer. of insulating material, and concomitantly receives heat from the hot olfgoing gases passing through the passage 52. As a result the heat input into the water'within the saturator is maintained. substantially constant during operation. For if the layer of ash around the grate and the basebuilds up during operation, thus cutting down transfer of heat by conduction into the saturator, at the same time the thickness of the layer of active fuel between the base and the central draft tube 50 is decreased so that the offgoing gas leaves the producer at a slightly higher temperature. And on the contrary if the ashes have just been'removed and the active fuel is thus separated from the saturator by a thinner layer of insulating material, with a consequently greater transfer of heat by conduction into the saturator, at the same time the thickness of the layer of fuel between the grate and the gas offtake is correspondin ly increased so that the ofigoing gases will be at a lower temperature. As a result uniform saturation is obtained. 7

This construction also is instrumental in securing suitable saturation at starting, without unnecessary delay in the introduction of moisture into the blast. For when the producer is started the layer of insulating material between the active zone ofthe fuelbed and the saturator is at a minimum, being merely the permanent layer of heat insulating material. rind consequently the resistance to the transfer of heat through this layer of heat insulating material is at a minimum. This feature is particularly desirable where the fuel has not any considerable quantity of volatile hydrocarbons in Where there are considerable quantities of volatile hydrocarbons these are normally driven off during the earlier action ofthe producer giving a gas of higher B. t..u. and it is desirable where such fuel is being used to delay the introduction of moisture until the volatile hydrocarbons have been substantially driven off, the enrichment of the gas resulting from the introduction of moisture serving to compencarbons being no longer present therein, thus giving a substantially uniform B. t. 11. throughout operation of the producer. But where fuel is used which has not considerable quantities of volatile hydrocarbons thereand the introduction of moisture is considerably delayed, the gas at first obtained will be of less B. t. u. than the gas subsequently obtained when moisture is introduced. l ilhen such fuel is used therefore it is desirable to introduce the moisture from the beginning of operations and the construction described above lends itself to this condition for if the producer is started with only the minimum, and permanent, layer of heat insulating material on the base the transfer of heat into the saturator takes place quickly and thus gives the desired saturation. Of

course if a fuel is used which containssubstan ial quantities of volatile hydrocarbon the layer of heat insulating material on the base may be increased as needed to give any desired delay in the introduction of moisture.

As statedabove the starting blower is preferably so positioned within the gas vofltake pipe that during operation only the resistance to draft of the fuel within the generating chamber of the producer must be overcome. This positioning of the startin-gbloweris not essential, since entirely satisfactory operation may be secured by positioning the blower beyond the purifier; but it is desirable that theblower be so positioned as to subject it to small resistance, so that the quantity, or volume, of air, or blast, passed through the fuel bed during the starting operation will be the maximum for a given apparatus. F or it has been found that the greater the quantity ofair which is caused to contact with a given quantity of incandescent carbon, during a given interval of time,the greater will cent carbon.

be the temperature of the incandescent carbon, and the better the quality of the gas. Positioning the starting blower as described, therefore,'makes for the minimum starting, or blowing up, period.

Furthermore, as stated above, it is desirable to so construct the apparatus that concentration of the blast will be secured during gas making operations. In the apparatus described, and particularly in the form of apparatus illustrated in Figs. 1 through 4,this desired condition is secured partly by that construction which prevents spreading of the blast along the base of the producer; It is still further-secured, particularly in the form of apparatus disclosed in Figs. 1 through 4, by constructing the grate in such fashion that it does nottend to diffuse or spread the blast. It is obvious, from inspection of the type of grate construction disclosed in Figs. 2, 3 and 4, that there is no tendency to cause a spreading of the blast after it leaves the upper end of the tuyere opening 40. As a result of thisconstruction the blast is concentrated so that a large'quantity of air will be brought into contact with the incandescent carbon, this. in turn causing the carbon'of the fuel bed to be maintained at a higher temperature than is the case where the same quantity orvolurne of blast is somewhat dissipated so that it is brought into contact with a larger quantity of incandes- Not only does this condition make for quicker starting, but it also results in the securing of gas of a better quality,'for

it has been found that byincreasing the concentration' of the blast so that a large quantity of air is brought into contact with a given quantity of incandescent carbon, the result is, for a given fuel bed depth and condition, a gas containing a greater percentage of combustible. v

The gas generating system shown herein, as illustrating a preferred embodiment of the invention, comprises an internal combustion engine which, as stated above, operates upon the generated gas and duringsuch operation supplies the suction for blastin the fuel. bed within the producer, to cause 1; e generation of the gas. Obviously in'such a type of plant the gas engine, during operation, utilizes all of the gas which is generated; since the blast throughthe fuel bed which causes the generation of gas is caused entirely by the suction of the engine during operation. The gas generating apparatus described hereinis not, however, limited' to a gas power plant of this character; but may be utilized for'supp'lying gas for any desired purpose. For example, a

gas producer constructed in accordance with course, a part of the gas generated could be used for operation of an internal combustion engine, if desired, that gas being fed to the inlet of the engine under slight pressure, in-

stead of under suction as is the case where the engine functions as the pump or exhauster. While the method hereindescribed, and the forms of apparatus for carrying this methodinto eifect,-constitute preferred embodiments of the invention, it is to be understood' that the invention is not limited to this precise method and forms of apparatus, and

that changes may bemade in either without departing from the scope of the invention which is defined in the appended claims;

What is claimed is:

. 1. A gas producer comprising a gas generating chamber, adapted-to contain a fuel bed;

a base member for supporting said fuel bed, a saturator in said base member, a gas offtake' passage within said base member below the said saturator; a central draft tube within the generating chamber above said basemember, a'gas offtake pipe connecting the said draft tube to the offtake passage within the said base member; the saturator being so located 7 within the base member as to receive heat on its upper side from the fuel bed resting on the said base member, and to receive heat on its lower side from the offgoing generated gases passing throughthe said ofi'take passage, whereby any increase ordecrease in the thickness of the layer of ash on the base member to decrease or increase the quantity of heat transferred to the saturator from the having a blast inlet opening therethrough, Y

and a grate member positioned mainly within said blast inlet opening. i 2. A gas producer comprising a gas generating chamber adapted to contain a fuel bed; a base member closing the lower end of said generatingohamber and adapted to support the fuel bed therein; means for introducing a blast of air and moisture into the fuel bed within said generating chamber to cause the generation of combustible gas; and a layer of heat insulation permanently maintained upon said base duringoperation, consisting of finely divided unburned carbonaceousmateriallof the character serving to constitute the fuel bed for the generation of gas but more finely divided than the bulk of the material of the fuel bed, said layer of heat insulating material serving to cut down the transfer of-heat from the active zone of the fuel 'bed into the base member.

3. A gas producer having a gas generating chamber adapted to contain a fuel bed having a laterally restricted active zone therein; and means for supporting said fuel bed, comprising a generally'fiat base member having a restricted central opening therein,

a worm grate positioned in said opening,

means for rotating said grate to cause ash to fmo'v'e downwardly through said grate and the opening in which it is positioned, and a scraper carried by said grate and extending laterallyover the base member, whereby upon rotation of the grate the scraper will move ash across the base member toward the said opening and the grate positioned therein, the

grate in turn moving said ash downwardly throughthe said opening, said scraper having-its free end upturned to conform to the outline of the active zone of the fuel bed.

4. A gas producer comprising a gas generating chamber adapted to contain a fuel bed a. base member, having an opening there in, closing the lower end of said generating chamber, an upstanding iiange surrounding said opening, asecond upstanding flange, carried bysaid base member, surrounding the first named flange and spaced therefrom, to form a trough adapted to receive finely divided heat insulating material; a grate positioned within said opening, a scraper arm carried by said'grate and extending laterally therefrom to overhang said trough, means for rotating the grate'and the scraper arm carried thereby, and partitions in said trough cooperating with the said scraper arm during rotation of the grate to crush clinker and the like.

5. In a gas producer comprising a gas generating ch amber adapted to contain a fuel bed and means for introducing a blast of air and moisture into said fuel bed to cause the gener ation of gas; a saturator, having an opening therein connecting the interior of said saturator to the blasting means, the bottom of said saturator being inclined; chicken feed mechanism of the character described for supplying water to said saturator; and a gas offt'ake pipe connected to the interior of said generating chamber and in heat exchange -7. A gas producer comprising a gas gen- 1 erating chamber adapted to contain a fuel bed; a base member closing the lower end of said generatingchamber and adapted to support the fuel bed therein; means for blasting the fuel bed within said generating chamber to cause the generation of combustible gas; an ofi'take passage within said base member, a gas 'offta'ke pipeconnecting the interior of the generating chamber to said offtaikepassage; a saturator withinsa-id'base member. in-heat exchange relation with said gas o-iftake passage, whereby the lowerwal'l of said saturator will receive heat from the heated generated gases passing off from the generating chamber through the said oiftarke passage; said saturator having an opening therein connecting the interior of said saturator'to the blasting means, the bottom of said saturator being inclined; andliquid levelcontrolling mechanism for controlling the supply of water to said saturatorito a level normally exposing a portion'of the inclined bottom of a said saturator, said mechanism being responsive to the dliferen'ces m pressure within said saturator due to variations in load on the producer to thereby increase the water level therein as the pressure decreases within said saturator and vice versa.

8. A gas producer comprising a gas gen-- erating chamber adapted to contain a fuel bed; a gas ofl'take passage connected withsaid generating chamber, through which the generated gases pass off from the generating chamber; asaturator coacting with said offtake passage in such wise as to be in heat receiving relation to the offgoing gases, said saturator having an opening therein connect-ing the interior "of the said saturator to the generating chamber of the producer; and means for supplying water to the interior of said saturator, said means being adapted to automatically vary the quantity of water within said saturator to accord with varia- 1 member having a central blast opening therein, said opening being of less diameter than the said base, and a Worm grate positioned Within said blast opening, the base member and grate being adapted to support the fuel bed within the generating chamber, the worm grate and blast opening being adapted for passage of the blast thru the said blast opening and grate Without causing substantial lateral spread thereof.

10. A gas producer comprising a gas generating chamber adapted to contain a fuel bed having a laterally-restricted active zone therein; and means for supporting the said fuel bed comprising a generally flatbasemember having a centrally-arranged blast opening therein, a Worm grate mounted Within said opening and carrying a member extending over the said fiat base member, and means for rotating said gate to cause ash Within the generating chamber and above the base member to move from the said base member thru said blast opening.

11. A gas producer comprising a gas generating chamber adapted to contain a fuel bed of solid carbonaceous material; a base member for supporting said fuel bed having a blast inlet opening therein of substantially less diameter than the said generating chamber; a draft tube positioned Within said generating chamber and adapted to be surrounded by fuel during operation, the draft tube and blast opening being so proportioned and positioned close to each other that the path of travel of the blast through the fuel bed Within said generating chamber during operation will be laterally restricted to limit the maximum extent of the active zone of said fuel bed so that such active zone will be during operation surrounded by azone of inactive fuel, and a layer of solid finely divided heat insulation material considerably smaller in size than the bulk of the material of the fuel bedpermanentlymaintainectduringoperation upon said base member about said blast inlet opening and between said base member and the active zone of the fuel bed for heat insulating the active zone of the fuel bed from the said base member to confine the heat Within said active zone, the pieces of fuel of the fuel bed directly resting thereon becoming imbedded in the finely divided heat insulating material and serving to further insure the said lateral restriction of the path of the blast through the fuel bed. I

In testimony whereof I hereto afiiX my signature.

HARRY F. SMITH.

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