US2920943A - Pneumatic rendering machine - Google Patents

Description

Jan. 12, 1960 J. R. HARRIS 2,920,943

PNEUMATIC RENDERING MACHINE Filed April 21, 1958 3 Sheets-Sheet 1 FIG.1

INVENTOR.

A f/orngy Jan. 12, 1960 J. R. HARRIS PNEUMATIC RENDERING MACHINE 3 Sheets-Sheet 2 Filed April 21, 1958 INVENTOR. John R H0 H5 BY WM W A fforney V 0: W. m 0:

Jan. 12, 1960 J. R. HARRIS PNEUMATIC RENDERING MACHINE Filed April 21, 1958 3 Sheets-Sheet 3 INVENTOR. John R Harr '5 BY 716,45 74 W A f/orney Q: 8 0Q: 0 Q \ww mw OK mu PNEUMATIC RENDERING MACHINE John R. Harris, Atlanta, Ga., assignor to Bullock Manufacturing Company, Inc., a corporation of Georgia Application April 21, 1958, Serial No. 729,573

8 Claims. (Cl. 23-269) This invention relates to pneumatic rendering machines and more particularly to rendering machines wherein material to be rendered is subjected to the rendering action of a flow of hot air while simultaneously being agitated mechanically.

In machines of this type it has been the practice to apply heat by applying steam to the material to be rendered or to enclose the material in a container to which heat is applied externally, the solid material being separated from the rendered liquid by wayof a perforated strainer. In some instances the air is heated by'being passed over or through: some sort of heat exchanger. Most such machines are inefficient due to poor utilization of heat or else produce a solid residue which is saturated with grease or may allow bits of solid material to accumulate in the rendered liquid.

A principal object of this invention is to provide a rendering machine of greatly improved efficiency especially insofar as heat utilization is concerned.

Another object of my invention is the provision of a safegas fired pneumatic rendering machine.

Still another object of my invention is to avoid subjecting the rendered liquid and the solid residue to any unnecessary heating while at the same time performing a thorough rendering operationthereby to improve the quality of the products produced by a rendering operation. I

A further object of this invention is the provision of an improved renderingmachine which is easy and simple to ing cavity for collecting the rendered liquid. Accord- .ingto a feature of the invention the outlet passage slants upwardly and communicates with the interior of the machine at a point between the rendering cavity and the United States Patent is an end view of the right hand end of the machine as viewed in Fig. 1; Fig. 3 is a cross sectional view taken along the line 3-3 as indicated in Fig. 1; Fig. 4 is an end view of the machine taken from the left hand end thereofas viewed in Fig. 1 and in which Fig. 5 is a schematic diagram showing the control system utilized in the operation and control of the device.

Generally speaking the device shown in Figs. 1-4 inclusive constitutes an enclosing structure in which a perforated rotatable drum is mounted. This enclosing structure is provided at the top part thereof with an inlet adjacent which is disposed an air heating meansin the form of a plurality of gas jets. An outlet is provided near the bottom of the enclosure through which air is drawn and expelled to atmosphere by means of a suction fan. The material to be rendered is loaded into the perforated drum manually and during the rendering operation the rendered liquid is extracted continuously by suitable pumping means which cooperates with a receiver disposed at the bottom of the apparatus and into which the rendered liquid is caused to flow by the action of gravity. With reference to Fig. 1 the numeral 1 designates. a metallic channel member which is disposed on the opposite side of the machine from a similarly constructed and arranged channel 2 as shown in Fig. 3. As can thus be seen in Fig. 3 the ends of channels 1 and 2 are interconnected by a third channel designated by the numeral 3. In similar fashion the right hand end of the device as viewed in Fig. 1 is provided with a channel similar to channel 3, this latter channel however is not apparent in any of the figures of the drawings. Thus it will be understood that the machine rests on a framelike base made up or a rectangularly arranged channel structure which is mounted'on feet 4, 5, 6 and 7. Afiixed as by welding or other suitable means to the corners of the channel frame above described is a plurality of angle irons 8,. 9 and 10, the angle iron disposed at the fourth corner not being visible in any of the views of the drawings. A rectangular channel frame. similar to that constituting channels 1, 2 and 3 and the other channel not shown is mounted atop the corner posts 8, 9 and 10 and the remaining post which does not appear in the drawings.

receiver. In this way the flow of exhaust air is thorough- I ly and efficiently separated from the rendered liquid. According to another feature of the invention a part of the wall of the machine is hingedly mounted so as to constitute an access door through which the solid residue may be removed and which also closes oli the exhaust passage and the receiver reservoir when the solid residue is being accompanying drawings in which Fig. 1 is a side view of a rendering machine embodying the invention: Fig. 2

This channel frame as best shown in Fig. 3 comprises a front channel 11, a back channel 12, and an end channel 13, the opposite end channel not appearing in any. of the views of the drawings. As already explained the frame of the machine can be assembled by welding or other suitable technique.

Affixed to the right hand end of the frame of the machine as viewed in Fig. l is a pair of end plates designated in Fig. 2 by the numerals 14 and 15. These end plates can be afiixed to the frame by suitable screws or by welding or by other means. As is best shown in Fig. 4, the

left hand end of the machine as viewed in Fig. 1 is provided with a pair of end plates 16 and 17 which are aifixed to the frame in a manner similar to the manner employed in securing end panels 14 and 15 in position. As is shown in Figs. 1 and 3, a'side panel 18 is constructed with a vertical portion 19 and an integrally formed downwardly slanted portion 20. As is shown in Fig. 3 the opposite side of the machine is provided with a side panel generally designated by the numeral 21 which constitutes a vertical portion 22 and an inclined portion 23.

As is best shown in Fig. 3 a pair of channels designated by the numerals 24 and 25 are arranged in vertically spaced relation and are disposed horizontally, these channels being affixed as by welding or otherwise to the corner angles 8 and 9. Since the channels have their flanges turned inwardly they are arranged to constitute mounting means for a pair of access doors 26 and 27. These doors are respectively provided with handles 28 3 and 29 and obviously'are slidable along the frame defined by the flanges of the channels 24 and 25.

As is seen in Fig. 3 the opposite side of the machine is 'similarly provided with access doors 30 and 31 which *are'mo'unted in 'the lower horizontally disposed channel interior of the enclosing'structure can be had from either side of the machine via the access doors 26 and 27 on one side or via doors 30 and 31 on the other side.

As is shown in Fig. 3 a pair of horizontally disposed channel membersis affixed to the end channels as by welding and these horizontal channels are designated by the numerals 35 and 36. A cover plate 37 is rectangular in shape andthe left hand edge thereof as viewed in Fig. 3 is mounted on the channel 25 and the right hand edge thereof .is supported by the channel 35 by way of a mounting strip 38 atfixed to channel 35 by bolts 39 and afiixed to cover plate 37 by bolts 40. Preferably the cover plate 37 is constructed of'a suitable heat insulat- -'-ing material arranged in a frame of metal.

A suitable insulating material for this purpose is glass wool. Disposed opposite the cover plate 37 is a similar cover plate 41 the right hand edge of which as viewed in Fig. 3 rests on the channel 33 and the left hand edge of which is supported on channel 36 by way of the support plate 42 afiixed to the cover plate 41 by bolts 43 and secured to the channel 36 by bolts 44.

As viewed in Fig. 3 a portion of the enclosing structure constitutes an access door 45 which is hingedly mounted at 46. Door 45 is movable from the position shown in Fig. 3 toward the right to its normal position so that its right hand surface engages the surface 23A of the downturned portion 23 of side plate 21.

The structure described above and including the end plates 14, 15,16 and 17, the'side plates 18 and 21, the doors 26, 27, 30 and 31, the 'cover plates 37 and 41, all constitute enclosing structure for the rotatable drum designated in Fig. 3 by the numeral 47. Drum 47 is perforated as indicated for example by the openings 48 and is provided with a plurality of internal baffles 49 and an access door 50 which normally is covered by a cover plate 51 secured to the drum by a plurality of bolts 52. Drum 47 is rotatably mounted on shaft 53. Shaft 53 is supported at each end on suitable cross pieces which are horizontally disposed and one of which is welded to the corner posts at the right hand end of the machine as viewed in Fig. l and the other of which will be described. -It will be understood that these cross pieces support end bearings on which the shaft 53 is rotatably mounted.

As is best shown in Fig. 3 the space between the horizontally disposed channels 35 and 36 constitutes an inlet passage through which air flows into the cavity formed within the enclosing structure and in which the drum 47 -is mounted. Furthermore as'shown in Fig. 3 the upwardly inclined passage 54 communicates with a hori- "zon'tally disposed transversely extending passage 55.

liquid from the sump 57. The receiver 56 and sump 57 normallyaccumulate the rendered liquid due to the "fact that door 45 normally is disposed with its right 4 hand surface in engagement with the surface 23A as viewed in Fig. 3 as alreadyexplained.

The left hand extremity of exhaust conduit 55 connects with a large vertically disposed exhaust conduit 58A in which a blower fan designated in Fig. 4 by the numeral 59A is mounted. Blower fan 59A as best shown in Fig. 4 is driven by a motor 60A which in turn is mounted on a table 61 by bolts 62. The motor 60A is arranged so as to drive the fan 59A by a belt 63. It will be understood that the vertical conduit 58A is arranged so as to extend upwardly and outside of the building in which the machine is mounted so as to exhaust the fumes resulting from the rendering process to atmosphere.

For the purpose of applying heat to the air supplied through the inlet passage, a pair of horizontally disposed fuel gas conduits 64 and 65 are mounted adjacent the channels 35 and 36 respectively. These conduits are provided with gas outlets 66 and 67 which constitute a plurality of gas jets disposed in the path of air following the direction of the arrows as shown in Fig. 3. In this way heat is imparted to the incoming air when gas from the jets is ignited.

In order to insure that the incoming air will be efficiently heated, a bafile plate 68 as shown in Fig. 3 is secured to "a pair of horizontally disposed channels 69 and 70 which in turn rest on the end channels of the frame. It will be understood that the bafile plate 68 functions to prevent air from coming into the inlet passage from directly above the passage and causes this air to follow the arrows and into close proximity with the sources of heat.

Gas to theconduits 66 and 67 is supplied through a main conduit 71 best shown in Figs. 1, 2, and 3. As is best shown in Fig. 1 horizontally disposed conduits 72 and 73 lead from the main conduit 71. Conduit 72 is connected with the vertical conduit 74 which in turn connects to a pair of vertically disposed conduits 75 and 76 as best shown in Fig. 4 which in turn connect to the conduits 64 and 65. In similar fashion the horizontally disposed conduit 73 connects to a vertically disposed conduit 77 which in turn connects with vertical conduits 78 and 79 as best shown in Fig. 2 which in turn communicate respectively with the conduits 64 and 65. As is best shown in Fig. 2 a suitable conduit is provided whereby gas is supplied to a pilot light and this pilot conduit is designated by the numeral 80.

The operation of the device as described thus far is as follows: With burning gas issuing from gas outlets 66 and 67 and with the fan 59A operating, a current of air is drawn through the inlet between channels 35 and 36 down through the drum 47 and out through the outlet passage 54, 55 to atmosphere via conduit 58A. Meanwhile the drum 47 is rotated by suitable means yet to be described and the rendered material disposed within the drum is agitated due to the rotation of the drum 47 and to the action of baffles 49. The heated air passes through the material to be rendered. The rendered liquid falls down into the receiver 56, 57 due to the action of gravity, the solid residue being retained within the drum 47. When a rendering operation is completed the 'machine is shut down, the gas is shut 013, and the drum and 31. Bolts 52 and door 51 are manually removed and the rendered solid material within the drum 47 is dumped out through the access opening 51 onto door 45 and panels 20 and 23 by rotating the drum 47. During the rendering operation the pump 59 continually draws oif rendered liquid.

In order to atford ready access to the end of the intc rior of the enclosing structure an access door 81 having a handle 82 may be suitably mounted in known fashion to the end plate 15 as best shown in Fig. 2. It will be understood that at least'a portion of the solid material dumped down on to the hingedly mounted plate 45 may shown in Fig. 4 the shaft 53 of the drum 47 is mounted in a bearing 84 secured by bolts 85 to a supporting frame 86 secured by bolts 87 atop table 88. Aflixed to shaft 53 is a sprocket 89 on which a driving chain 90 is mounted which in turn is driven by the sprocket 91. Sprocket 91 is mounted on shaft 92 which in turn constitutes one ele- -ment of a speed changer designated generally by the numeral 93 in the drawings. Also constituting one shaft of the speed changer 93 is shaft 94 and its associated pulley 95 on which a belt drive 96 is mounted and which in turn cooperates with the pulley 97 mounted on the shaft 98 of main motor 99. Motor 99 is affixed by bolts 100 to the table 83. Thus with power applied to main driving motor 99 the speed changer 93 is actuated through its shafts 94 and 92 and in turn drives the chain 90 to impart rotary motion to sprocket 89 and shaft 53.

For the purpose of controlling the motor 99 in such fashion as to impart controlled stopping movement thereto the arrangement shown in Fig. 5 has proved to be satisfactory. For instance the access door 50 of drum 47 should bear a predetermined space relationship to the access doors 26 and 27 or 30 and 31 in order to perform a loading or unloading operation. For this reason suitable switch means dependent on the angular relationship of the drum 47 relative to the doors 30, 31 and 26, 27 is used together with a suitable magnetic brake to determine the eXact position at which the drum stops when the machine is shut down.

As is shown in Fig. 5 thedriving motor 99 is designated by the letter M and the drum 47' or load on the motor is designated by the letter L. The shaft 53 is schematically represented in Fig. 5 as a dotted line. In Fig. 5 the letter B designates the rotatable element of a magnetic brake which in actuality is formed integrally within the speed changer 93 and is not shown in detail in Fig. 4 since this particular device forms no part of the present invention.

The cam operated switch designated by the letters CS is also aflixed to the shaft 53 and is designated schematically in both Figs. 4 and 5.

Energy to the driving motor 99 is supplied through lines L1, L2 and L3 by way of the contacts of the relay generally designated by the numeral 101. The circuit for energizingathe coil 102 of relay 101 includes the stop-button 103 which of course is normally closed in conventional fashion and the start button 104 which is normally open together with certain elements of the selector switches S1 and S2.

In order to start the motor the selector switches S1 and S2 are both closed in their down positions, that is, with their blades connected with their lowermost poles. With the switches S1 and S2 down, the start button is depressed. In this manner a circuit is completed from L2 through the stop button 103, start button 104, conduit 105, switch S1, cross conduit 106, conductor 107, switch S2, conductor 108, conductor 109, coil 102 of relay 101 and back to line L1. When so energized the operating elements of relay 101 pick up and close. all of the relay contacts. t

Should the operator not close either or both of the switches S1 or S2 to their down positions, i .e. should both switches be open as shown in Fig. 5, the system will still start the motor 99 because the switch S1 and conductor 106 are by-passed by the normally closed contacts of relay 125 which are connected between line and line 107 via 1ine126 and because the switch S2 and conductor 108 are by-passed by the normally closed contacts of relay 127 which interconnect with lines 107 and 109 via the lines 129 and 128 respectively. i

When the coil 102 of relay 101 picks up, power is supplied to motor M and the motor starts. The relay coil 102 is sealed in in conventional fashion by a circuit comprising conductor 110, the upper connecting element 111- of the relay, and conductor 112 which circuit constitutes a short circuit around the start button. Thereafter release of the start button does not result in a dropping out of the relay 101. When relay 101 picks up the coil 113 of relay 114 is energized and picks up its normally closed contacts thereby de-energizing the field coils 115 of the magnetic brake. As is shown in Fig. 5 the field coils 115 of the magnetic brake are energized from a'suitable source of alternating current and a conventional rectifier 116 which is arranged in series 'With a rheostat 117 and with the contacts of the relay 114. In this manner the magnetic brake is de-energized as the motor simultaneously begins to drive the drum 47.

In practice I have found that it is desirable to control a rendering operation on a definite time basis. Thus after the timer indicates the completion of an operation, one of the switches S1 or S2 is moved from its intermediate or down position to its up position, the particular switch depending on whether it is desired to stop the drum 47 with its access opening 50 adjacent to doors 26, 27 or whether it is desired to have the access door 50 stop adjacent to doors 30 and 31. In any event one of the selector switches S1 or S2 is moved to its up position. Assuming that the switch S1 is moved to the up position the coil of time delayed relay is energized and its contacts opened after a predetermined interval of delay and the circuit from line L2 energizing the relay coil 102 includes the stop button 103, the connector 110, the contact 111, the connector 112, connector 105, the switch S1, the conductors 119 and 120, the normally closed contact 118 of the cam switch CS, the conductor 107, the switch S2, the conductor 108 (or the lines 129 and 128 and contacts of relay 127 if S2 is in its intermediate position) and conductor 109 through the coil 102 and back to line L1. Thus on the next succeeding revolution of drum 47 and shaft 53 occurring after time delayed operation of relay 125 the cam portion 121A of the cam switch CS will open the cam switch 118 at a predetermined time relative to the position of the drum 47 with respect to one or the other of the access doors 26, 27 or 30, 31. In this manner the relay coil 102 is deenergized and the coil 113 of relay 114 is deenergized and closes its contacts thereby to apply power to the magnetic coils 115 of the magnetic brake B. With the brake applied and the power off of the motor 99 the drum 47 is stopped in a predetermined fashion at a predetermined time.

In similar fashion it will be understood that the drum 47 could be stopped at a different position relative to the enclosing structure and to the doors by simply closing the selector switch S2 to the up position while leaving the selector switch S1 in its down or intermediate position.

'In this manner control would be placed on the cam switch contact 122 which through conductors 123 and 124 and other circuit elements would deenergize the coil 102 after predetermined time delay caused by delayed operation of time delay'relay 127 Whose contacts are in parallel with contacts 122 when switch S2 is in its up position, in a manner which is obvious from Fig. 5.

In Fig. 4 the cam switches 118 and 122 are'schematically designated and the cam portion 121A of the ca 121 is indicated schematically.

From the description thus far it will be seen that if it is desired to stop the drum 47 with its access door 51 adjacent the one set of doors such as 26, 27 for example, one selector switch such as S1 would be closed to its up position and the drum would promptly stop rotating and the access door 51 would register with the doors 26, 27.

, Thereafter bolts 52 and door 51 are removed by an operator who gains access thereto via doors 26, 27. Thereafter the switch S1 is pulled to its intermediate or down position and the start button 104 depressed. The drum 4'] beginsto rotate again and the solid' residue is thrown out through door-51 and into thecavity of the machine, the solids falling down onto panels 20, 23 and door 45. When the solids are all removed from drum 47 switch -S1 or $2 is moved to its up position and the drum 47 stops with its door 51 in registry with cavity doors 26, 27 or 30, 31 as the case may be. The machine is then ready to be reloaded manually.

After reloading door 51 is afiixed in place by bolts 52 and door 45 is swung clockwise to engage panel 23 at 23A and the start button 104 depressed to begin another rendering cycle.

While I have shown and described a particular embodiment of the invention I do not wish to be limited thereto and intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed below said cavity and in direct communication therewith, an inlet passage formed in the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the-lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, means for causing atmospheric air to enter said cavity through said inlet and to leave said cavity through said outlet, means defining a plurality of fuel gas outlets disposed about the exterior of said inlet passage and adjacent thereto, and bafile means spaced from the outer part of said inlet passage for causing air entering said inlet passage to pass closely adjacent said gas outlets and to follow a tortuous path to the interior of said cavity whereby the air is heated without exposing the material in said rendering cavity to the flames formed at said gas outlets.

2. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed below said cavity and in direct communication therewith, an inlet passage formed in the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, means for causing atmospheric air to enter said cavity through said inlet and to leave said cavity through said outlet, a pair of spaced substantially parallel fuel gas conduits disposed respectively on opposite sides of said inlet passage, a plurality of gas outlets formed in each of said conduits, and bafile means spaced from the outer part of said inlet passage for causing air entering said inlet passage to pass closely adjacent said gas outlets and to follow a tortuous path to the interior of said cavity whereby air flowing therethrough is heated without exposing the material to be rendered in said rendering cavity to flames formed at said gas outlets.

3. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed below said cavity and indirect communication therewith, an inlet passage formed in the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, a portion of said structure generally opposite from said outlet being movable from a normal position to another position to establish an access opening to the bottom of said cavity, means for causing atmospheric air to enter said cavity through said inlet and to leave said.

cavity through said outlet, means defining a plurality of fuel gas outlets disposed about the exterior of said inlet passage and adjacent thereto, and baffle means spaced from the outer part of said inlet passage for causing air entering said' inlet passage to pass closely adjacent said gas outlets and to follow a tortuous path to the interior of said cavity so as to prevent exposure of the contents of said rendering cavity to contact with flames at said gas outlets.

4. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed below said cavity and in direct communication therewith, an inlet passage formed in the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, a portion of said structure generally opposite from said outlet being movable from a normal position to another position preventing communication between said cavity and said receiver, means normally causing atmospheric air to enter said cavity throughsaid inlet and to leave said cavity through said outlet, and means disposed adjacent said inlet for increasing the temperature of air entering said cavity through said inlet.

5. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed. below said cavity and in direct communication therewith, an inlet passage formedin the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, a portion of said structure generally opposite from said outlet being hingedly mounted for swinging movement from a normal position to another position to establish an access opening to the bottom of said cavity and to prevent communication between said cavity and said receiver, means normally causing atmospheric air to enter said cavity through said inlet and to leave said cavity through said outlet, and means disposed adjacent said inlet for increasing the temperature of air entering said cavity through said inlet.

6. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed below said cavity and in direct communi cation therewith, an inlet passage formed in the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, a portion of said structure generally opposite from said outlet being movable from a normal position to another position to establish an access opening to the bottom of said cavity and to prevent communication between said cavity and said outlet, means normally causing atmospheric air to enter said cavity through said inlet and to leave said cavity through said outlet, and means disposed adjacent said inlet for increasing the temperature of air entering said cavity through said inlet.

7. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed below said cavity and in direct communication therewith, an inlet passage formed in the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, a portion of said structure generally opposite from said outlet being movable from a normal position to another position to establish an access opening to the bottom of said cavity, and to prevent communication between said cavity and said outlet and between said cavity and said receiver, means normally causing atmospheric air to enter said cavity through said inlet and to leave said cavity through said outlet, and means disposed adjacent said inlet for increasing the temperature of air entering said cavity through said inlet.

8. A rendering machine comprising enclosing structure defining therein a rendering cavity and a liquid receiver disposed below said cavity and in direct communication therewith, an inlet passage formed in the upper portion of said structure and establishing communication between atmosphere and said cavity, an outlet formed in the lower portion of said structure and establishing communication between atmosphere and said cavity, said outlet being disposed at a level below said cavity and above said receiver, a portion of said structure generally opposite from said outlet being hingedly mounted for swinging movement from a normal position to another position to establish an access opening to the bottom of said cavity and to prevent communication between said cavity and said receiver, means normally causing atmospheric air to enter said cavity through said inlet and to leave said cavity through said outlet, an upwardly slanted outlet passage leading from said outlet, and means disposed adjacent said inlet for increasing the temperature of air entering said cavity through said inlet.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. A RENDERING MACHINE COMPRISING ENCLOSING STRUCTURE DEFINING THEREIN A RENDERING CAVITY AND A LIQUID RECEIVER DISPOSED BELOW SAID CAVITY AND IN DIRECT COMMUNICATION THEREWITH, AN INLET PASSAGE FORMED IN THE UPPER PORTION OF SAID STRUCTURE AND ESTABLISHING COMMUNICATION BETWEEN ATMOSPHERE AND SAID CAVITY, AN OUTLET FORMED IN THE LOWER PORTION OF SAID STRUCTURE AND ESTABLISHING COMMUNICATION BETWEEN ATMOSPHERE AND SAID CAVITY, SAID OUTLET BEING DISPOSED AT A LEVEL BELOW SAID CAVITY AND ABOVE SAID RECEIVER, MEANS FOR CAUSING ATMOSPHERE AIR TO ENTER SAID CAVITY THROUGH SAID INLET AND TO LEAVE SAID CAVITY THROUGH SAID OUTLET, MEANS DEFINING A PLURALITY OF FUEL GAS OUTLETS DISPOSED ABOUT THE EXTERIOR OF SAID INLET PASSAGE AND ADJACENT THERETO, AND BAFFLE MEANS SPACED FROM THE OUTER PART OF SAID INLET PASSAGE FOR CAUSING AIR ENTERING SAID INLET PASSAGE TO PASS CLOSELY ADJACENT SAID GAS OUTLETS AND TO FOLLOW A TORTUOUS PATH TO THE INTERIOR OF SAID CAVITY WHEREBY THE AIR IS HEATED WITHOUT EXPOSING THE MATERIAL IN SAID RENDERING CAVITY TO THE FLAMES FORMED AT SAID GAS OUTLET.

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