US3882797A

US3882797A - Expansion grate for incinerator

Info

Publication number: US3882797A
Application number: US481103A
Authority: US
Inventors: Christian A Eff
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1974-06-20
Filing date: 1974-06-20
Publication date: 1975-05-13
Anticipated expiration: 1992-05-13

Abstract

An incinerator including a combustion chamber is provided wherein an expansion grate is disposed proximate the entrance to the combustion chamber. The expansion grate is movable between an extended position in which the amount of combustible materials which may be deposited within the incinerator is limited and a retracted position in which the combustible materials fall to the bottom of the combustion chamber for incineration. The incinerator also includes a mechanically interconnected loading door and combustion chamber access cover. When it is desired to load the combustion chamber with combustible materials, the expansion grate is placed in its extended position and the loading door and access cover are opened. As long as the expansion grate is not retracted, the loading door and access cover may be opened repeatedly to deposit more combustible materials. However, when the expansion grate is retracted, an interlock means and locking means combine to keep the loading door locked until an incineration cycle is completed. Thus, it is impossible to overload the combustion chamber with combustible materials or to open the loading door during the incineration cycle.

Description

United States Patent [1 1 Eff [ EXPANSION GRATE FOR INCINERATOR Christian A. Eff, Louisville, Ky.

[73] Assignee: General Electric Company,

Louisville, Ky.

[22] Filed: June 20, 1974 [21] Appl. No.: 481,103

[75] Inventor:

2,783,723 3/1957 Loewenthal et a1. 110/18 3,467,035 9/1969 Anderson et a1. 1lO/l8 3,742,874 7/1973 Eff l10/8 Primary Examiner-Kenneth W. Sprague 57] ABSTRACT An incinerator including a combustion chamber is [4 1 May 13,1975

provided wherein an expansion grate is disposed proximate the entrance to the combustion chamber. The expansion grate is movable between an extended position in which the amount of combustible materials which may be deposited within the incinerator is limited and a retracted position in which the combustible materials fall to the bottom of the combustion chamber for incineration. The incinerator also includes a mechanically interconnected loading door and combustion chamber access cover. When it is desired to load the combustion chamber with combustible materials, the expansion grate is placed in its extended position and the loading door and access cover are opened. As long as the expansion grate is not retracted, the loading door and access cover may be opened repeatedly to deposit more combustible materials. However, when the expansion grate is retracted, an interlock means and locking means combine to keep the loading door locked until an incineration cycle is completed. Thus, it is impossible to overload the combustion chamber with combustible materials or to open the loading door during the incineration cycle.

8 Claims, 4 Drawing Figures FATENTEU my 1 3197s SHEET 2 OF 3 F'IG.Z

PATENTED MAY 1 3 I975 SHEEI 30? 3 EXPANSION GRATE FOR INCINERATOR BACKGROUND OF THE INVENTION The invention relates to incinerators and, more particularly, to an improved expansion grate disposed within the combustion chamber of an incinerator for limiting the amount of combustible materials which may be placed within the combustion chamber and to interlock means for preventing improper operation of the incinerator.

A problem in incinerators is overloading of the combustion chamber. This may be a serious problem since an overloaded or tightly packed combustion chamber may result in poor combustion, large carbon masses that are impossible to burn, increased time for complete incineration, and localized hot spots within the combustion chamber. Additionally, if an agitator is provided to stir combustible materials, overloading of the combustion chamber may cause jamming of the agitator with resultant damage thereto.

A further problem arising through overloading of the combustion chamber is that combustible materials placed in the combustion chamber may contact heating units for the combustion chamber, resulting in inefficiency, overheating, or damage to the heating units. If the combustible materials have been tightly packed within the combustion chamber, forces may be transmitted from the agitator through the combustible materials to the heating units, resulting in damage to the heating units.

In view of the above-mentioned problems, it is an object of the present invention to prevent the overloading of the combustion chamber of an incinerator and thus avoid the problems of unburned carbon masses, combustion inefficiency, increased incineration times, and localized hot spots within the combustion chamber.

It is another object of the invention to prevent jamming of an agitator disposed within the combustion chamber of an incinerator due to overloading the combustion chamber and thus avoid damage to the agitator.

It is a further object of the invention to prevent improper operation of the incinerator by the user.

SUMMARY OF THE INVENTION In carrying out the invention, in one form thereof, an incinerator including a combustion chamber is provided wherein an expansion grate is disposed proximate the entrance to the combustion chamber. The expansion grate is movable between a first or extended position in which the amount of combustible materials which may be deposited within the incinerator is limited and a second or retracted position in which the combustible materials fall to the bottom of the combustion chamber for incineration. When it is desired to load the combustion chamber with combustible materials, the expansion grate is placed in its extended position and the loading door and access cover are opened. As long as the expansion grate is not retracted, the loading door may be opened repeatedly to deposit more combustible materials. However, when the expansion grate is retracted, an interlock means and locking means combine to keep the loading door locked until an incineration cycle is completed. Thus, it is impossible to overload the combustion chamber with combustible materials or to open the loading door during the incineration cycle.

.DESCRIPTION OF THE DRAWINGS FIG. 1 is a right side, cross-sectional, elevational view of an incinerator according to the invention showing a loading door and access cover in a closed position and showing in solid lines and dotted lines an expansion grate in extended and retracted positions, respectively.

FIG. 2 is a plan view of an incinerator according to the invention taken along line 2-2 of FIG. 1 and showing an arm and hinge means for the expansion grate.

FIG. 3 is a schematic circuit showing the interlock means and locking means of the present invention.

FIG. 4 is a fragmentary schematic drawing of the locking means for the loading door.

DESCRIPTION OF THE INVENTION The present invention deals with an improved incinerator structure. The description in the present application is directed only to those portions of the overall incinerator structure which comprise the present invention. For a more complete description of the basic incinerator structure with which the present invention is employed, reference may be had to two prior patents issued to the assignee of the present invention, U.S. Pat. No. 3,742,874, Solid Waste Incinerator, and U.S. Pat. No. 3,788,243, Domestic Solid Waste Incinerator.

Referring to FIGS. 1 and 2, there is shown an incinerator 10. Incinerator 10 includes an outer incinerator housing 12 of sheet metal, box-like construction that defines the outer limits of the incinerator and forms a supporting structure for the operational components of the incinerator. It will be appreciated that an incinerator is a high temperature device reaching temperatures above 1500F in some areas and that thermal insulating means must be provided within housing 12 to insure that the external surface temperatures of the incinerator are kept low. An air space 11 is formed interiorly of each outer wall of housing 12 by means of an insulation wall 14 spaced from housing 12 and which insulation wall has associated therewith a layer of thermal insulation 13.

The incinerator includes a combustion chamber 20 formed by an inner liner 22. The inner liner 22 has a forwardly inclined, semicylindrical front wall 26 with a bottom wall 28, a generally vertical rear wall 30, and a top wall 32 having a downwardly inclined front portion 33. An access cover 34, which provides for loading the incinerator with combustible materials through a loading door 36, cooperates with an opening 35 in the inclined front portion 33. Moreover, access cover 34 is provided with a sealing gasket 38 which is adapted to be compressed tightly against the peripheral flange of opening 35 for rendering the combustion chamber 20 generally airtight and precluding the escape of heated gases, smoke, odors, vapors, and the like. Loading door 36 and access cover 34 are integrated to move together by a suitable mechanical linkage 40 so that they can be moved with one hand, leaving the other hand free to deposit combustible materials through opening 35.

It is possible to locate the incinerator heating means so that the heating means are in direct contact with the combustible materials. The heating means could be located within combustion chamber 20 adjacent the top of inner liner 22 and away from opening 35. However, it has been deemed preferable to locate the heating means in the form of a resistance heating element 41,

shown schematically in FIG. 3, in the main heater compartment 42 which is positioned at the front of the incinerator housing generally beneath the forwardly inclined, semi-cylindrical front wall 26 of inner liner 22.

Combustion chamber includes an agitator 44 disposed in the lower portion thereof, directly above bottom wall 28. Agitator 44 is driven by a shaft 46, which shaft is in turn driven by an agitator motor 48. Agitator motor 48 is not shown in FIG. 1 since it is disposed within a housing 50. However, agitator motor 48 is shown schematically in FIG. 3.

Further included within combustion chamber 20 is an expansion grate 52. Expansion grate 52 is comprised of a short, flat portion 54, which flat portion is hingeably mounted at one end to downwardly inclined front portion 33 of top wall 32 by a hinge means 56. Expansion grate 52 also comprises a downwardly extending portion 58 of spaced parallel bars having a semicylindrical end portion 60, which end portion mates with the inner liner 22 when expansion grate 52 is in its extended position as shown by the solid lines in FIG. 1. In its extended position the grate 52 defines a loading chamber 61 into which combustible materials may be deposited. The size of the loading chamber 61, relative to the size of full combustion chamber 20 available when the grate is in its retracted position, insures that the combustible material will not be tightly packed in chamber 20 and combustion will be efficient. It will be understood that expansion grate 52 could be mounted for movement within combustion chamber 20 by any well-known means, and hinge means 56 is intended only as illustrative of one type of mounting.

In order to extend and retract expansion grate 52, an actuating mechanism is included therewith. The actuating mechanism comprises an arm 62 having a handle 64 at the outer end thereof. Both expansion grate 52 and arm 62 are rigidly affixed to hinge means 56 so that for every movement of arm 62 there is a corresponding movement of expansion grate 52. Handle 64 extends beyond housing 12 so that the operator may extend or retract expansion grate 52 from outside the incinerator housing. As shown in FIG. 1, when expansion grate 52 is in its first or extending position as shown by the solid lines, arm 62 and handle 64 are in their raised positions as shown by the solid lines. Conversely, when expansion grate 52 is in its second or retracted position as shown by the dotted lines, arm 62 and handle 64 are in their lowered positions as shown by the dotted lines.

In order to prevent overloading of combustion chamber 20 and to prevent loading door 36 from being opened until after an incineration cycle has been completed, an interlock means 66 and locking means 68 are provided to lock loading door 36 once expansion grate 52 has been retracted. Referring to FIG. 3, interlock means 66 and locking means 68 are shown as part of a schematic representation of the electrical circuitry of the incinerator.

Interlock means 66 comprises, in part, an interlock thermostat 70 connected across line L and grounded neutral connector N, which interlock thermostat includes a normally closed switch 72 and a normally open switch 74. If the temperature within combustion chamber 20 should rise above a predetermined temperature, such as approximately l40F, switch 72 is opened and switch 74 is closed. Interlock means 66 further comprises a door interlock switch 76 in series with line L an expansion grate interlock switch 78 in series with line L and a normally closed switch 80 connected across line L, and grounded neutral connector N through interlock thermostat 70.

In order to actuate

switches

76, 78, and 80, an actuating system is provided. Referring to FIG. 1, the actuating system for door interlock switch 76 comprises a push rod 82 disposed near the top portion of the incinerator, which push rod extends from switch 76 to door 36. Push rod 82 is supported by a pair of guides 84 and includes a stop 86 rigidly affixed thereto. A spring 88 is disposed intermediate stop 86 and one of the guides 84. Push rod 82 is axially translated upon the opening or closing of loading door 36 and this in turn actuates switch 76. Switch 76 is closed when loading door 36 is closed and is opened when loading door 36 is opened. Similarly, the actuating mechanism for

switches

78 and 80 comprises a push rod 90, guides 92, and spring 96. Push rod 90 is translated in response to movements of arm 62 such that switch 78 is closed when expansion grate 52 is retracted and is opened when expansion grate 52 is extended. Switch 80 is also actuated in response to movements of the push rod 90, except that switch 80 is open when switch 78 is closed and vice versa.

Referring to FIGS. 1, 3 and 4, the locking means 68 includes a locking bolt 98 having a tab 100 at one end thereof. The tab is arranged for engaging a slot 102 in loading door 36 to lock the door. As most clearly shown in FIG. 4, the locking bolt 98 is mounted on a pivot 104 and is biased toward its locking position by a spring 106. A solenoid 108, when energized, causes the locking bolt 98 to move counterclockwise to a sufficient extent to allow the tab 100 to clear the upper end of the door 36. When the door is in its closed position and the solenoid is de-energized, the tab 100 falls into the slot 102 in the door to lock the door in its closed position.

The solenoid 108 is momentarily energized for actuation of the locking bolt 98 by a momentary contact switch 110. The switch 110 and the solenoid 108 are connected between line L and grounded neutral connector N in series with interlock thermostat 70 and switch 80.

A second pivoted locking bolt 112, shown schematically in FIGS. 2 and 3, is arranged for engaging openings in side extensions of arm 62 to lock the arm and its associated expansion grate 52 in position. Specifically, the extensions 114 and 116 (shown also in FIG. 1) of arm 62 include

openings

118 and 120, respectively. The locking bolt 112 includes a tab 122 at one end which is arranged to be received in opening 120 for holding the arm 62 in its upper position which corresponds to the extended position of the expansion grate 52. The arm 62 is locked in its lower position, corresponding to the retracted position of the expansion grate, by engagement of the tab 122 with the opening 118 in arm extension 114.

A solenoid 126 is provided for effecting release of the second locking bolt 112. A spring 125 normally pivots the locking bolt 112 into engagement with the

holes

118 or 120 of the

side extensions

114 and 116. This solenoid is energized by means of a momentary contact switch 128 to counteract the action of the spring 125. The switch 128 and the solenoid 126 are connected to line L, through door interlock switch 76 and grounded neutral connector N through contacts 72 in the interlock thermostat 70. Thus, momentary actuation of switch 128, which is spring biased to its open position, effects energization of solenoid 126 to cause counterclockwise movement of the locking bolt 112 and retract the tab 122 of second locking bolt 110 from engagement with one of the

openings

118 or 120 to permit movement of the arm 62 and expansion grate 52.

The circuit for solenoid 126 includes interlock thermostat 70 so that so long as switch 72 is open (that is, when incinerator temperature is over 140F) the solenoid 126 cannot be energized by closing switch 128 and the arm 62 cannot be shifted from its lower (or dotted line position in FIG. 1) position and the expansion grate 52 is retained in its second or retracted position.

OPERATION It will be assumed that an incineration cycle has been completed and that it is desired to load the combustion chamber with more combustible materials prior to initiating another incineration cycle. It will be assumed further that the temperature within combustion chamber 20 has fallen below approximately 140F so that switch 72 is closed and switch 74 is open. Switch 76 is closed since loading door 36 is closed; also, switch 78 is closed and switch 80 is open since expansion grate 52 is in its retractedposition. Before the loading door 36 can be opened for deposition of combustible materials within combustion chamber 20, expansion grate 52 must be moved to its extended position by means of the handle 64.'Moving the grate to its extended position closes switch 80. With switch 80 closed, solenoid 108 may be energized by pushing momentary contact switch .110, thereby moving tab 100 of locking bolt 98 out of slot 102 in loading door 36. This permits loading door 36 to be opened and combustible materials to be deposited in the incinerator.

Referring particularly to FIG. 4, it will be seen, once door 36 is opened, tab 100 of locking bolt 98 cannot engage slot 102 until solenoid 108 is again energized. Thus, the operator may repeatedly deposit more combustible materials until the chamber defined by expansion grate 52 is full, merely by opening and closing loading door 36 without pushing momentary contact switch 110. Since solenoid 108 must be energized to lock or unlock loading door 36, door 36 is in a so-called almost closed condition (as shown in FIG. 4) after it has been unlocked upon the completion of an incineration cycle.

It will now be assumed that the operator desires to initiate another incineration cycle. Referring to FIG. 3, it is seen that both

switches

76 and 78 must be closed in order to permit electrical current to flow to the electrical components of the incinerator. This can be accomplished only by both closing loading door 36 and retracting expansion grate 52. When expansion grate 52 is moved to its retracted position, any previously deposited combustible materials fall to the bottom of combustion chamber 20. However, since the materials will now occupy a greater volume due to the retraction of expansion grate 52, combustion will be very efficient.

Once incineration has commenced and the temperature within combustion chamber 20 has exceeded appoximately 140F, it will be impossible for the operator to overload combustion chamber 20 by depositing more combustible material in the incinerator. This is because interlock thermostat 70 causes normally open switch 74 to close and normally closed switch 72 to open when the temperature reaches F, thereby preventing thecompletion of a circuit through switch 128 and solenoid 126. Thus, solenoid 126 cannot be energized to move the bolt 112 out of engagement with opening 118 and permit the handle 64 to be raised and the expansion grate 52 to be moved to its extended position until switch 72 is caused to close by the lowering of the temperature within combustion chamber 20 below 140F. After the incinerator has cooled below 140F, expansion grate 52 may be extended and thereafter loading door 36 may be opened.

Many advantages result from the use of the present invention. For example, the present invention eliminates the problem of large unburned carbon masses and localized hot spots. Additionally, jamming of agitator 44 with resultant damage to agitator 44 is no longer a problem since it is impossible for the operator to tightly pack combustible materials against agitator 44. A further advantage of the present invention is that if it were desired to locate. heating elements adjacent back wall 30, the heating elements would be protected from direct contact with combustible materials by portion 58 of expansion grate 52. Thus, forces cannot be transmitted from agitator 44 through the combustible materials to the heating elements nor could damage to the heating elements occur through direct contact with combustible materials during incineration.

The interlock means and locking means of the present invention serve to prevent the operator from loading the loading chamber, retracting expansion grate 52, and then once again extending expansion grate 52 in order to load more combustible materials into loading chamber 61. This is so, even at temperatures below about 140F, because the presence of the first load that had been dumped would prevent the grate from being extended back into the full line position of FIG. 1. Moreover, since expansion grate 52 must be extended before loading door 36 is unlocked after an incineration cycle, the chances of a fire occurring due to the operator dropping additional combustible materials to the bottom of combustion chamber 20 are eliminated. This is because contact between additional combustible materials and any hot ash remaining in the bottom of combustion chamber 20 after the completion of an incineration cycle is precluded by the extended expansion grate. Thus, the present invention permits maximum utilization of the incinerator in that the operator may repeatedly load loading chamber 61 with combustible materials until it is full; further, the present invention solves all of the previously mentioned problems of incinerators resulting from overloading of the combustion chamber; and still further, by utilizing an interlock means and locking means, the present invention prevents the operator from defeating the purpose of the expansion grate.

Although a specific embodiment of the invention has been described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention. It is therefore intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In an incinerator comprising a combustion chamber, a loading door for the incinerator, and heating means for incinerating combustible materials disposed within the combustion chamber, the improvement comprising:

an expansion grate disposed within said incinerator,

said expansion grate being mounted in said incinerator for movement between a first position in which said expansion grate defines a loading chamber to limit the amount of combustible materials which may be placed in the incinerator and a second position in which said combustible materials are discharged from said loading chamber into said incinerator.

2. The incinerator of claim 1 wherein said expansion grate is hingeably mounted for movement between said first and second positions.

3. The incinerator of claim 1 including an arm for moving said expansion grate between its first and second positions.

4. The incinerator of claim 3 including:

a. means for locking said door in its closed position,

and

b. means for preventing the unlocking of said door until incineration is complete.

5. The incinerator of claim 3 including:

a. means for locking said arm in a position corresponding to the second position of said expansion grate, and

b. means for preventing the unlocking of said arm until incineration is complete.

6. The incinerator of claim 5 including:

a. a first locking bolt arranged to engage said door for locking said door in its closed position,

b. a first solenoid for actuating said bolt to its unlocked position to permit opening of said door, and

c. means for preventing energization of said solenoid until the incineration is complete.

7. The incinerator of claim 6 further including:

a. a second locking bolt for locking said expansion grate in its second position,

b. a second solenoid for actuating said bolt to permit movement of said expansion grate from its second position to its first position, and

0. means for preventing energization of said solenoid until the incineratioin is complete.

8. The incinerator of claim 7 including:

a. an arm connected to said expansion grate for moving said grate between its first and second positions, and

b. said arm including a portion having an opening therein, said bolt engaging said opening to lock said grate in the second position.

Claims

1. In an incinerator comprising a combustion chamber, a loading door for the incinerator, and heating means for incinerating combustible materials disposed within the combustion chamber, the improvement comprising: an expansion grate disposed within said incinerator, said expansion grate being mounted in said incinerator for movement between a first position in which said expansion grate defines a loading chamber to limit the amount of combustible materials which may be placed in the incinerator and a second position in which said combustible materials are discharged from said loading chamber into said incinerator.

4. The incinerator of claim 3 including: a. means for locking said door in its closed position, and b. means for preventing the unlocking of said door until incineration is complete.

5. The incinerator of claim 3 including: a. means for locking said arm in a position corresponding to the second position of said expansion grate, and b. means for preventing the unlocking of said arm until incineration is complete.

6. The incinerator of claim 5 including: a. a first locking bolt arranged to engage said door for locking said door in its closed position, b. a first solenoid for actuating said bolt to its unlocked position to permit opening of said door, and c. means for preventing energization of said solenoid until the incineration is complete.

7. The incinerator of claim 6 further including: a. a second locking bolt for locking said expansion grate in its second position, b. a second solenoid for actuating said bOlt to permit movement of said expansion grate from its second position to its first position, and c. means for preventing energization of said solenoid until the incineratioin is complete.

8. The incinerator of claim 7 including: a. an arm connected to said expansion grate for moving said grate between its first and second positions, and b. said arm including a portion having an opening therein, said bolt engaging said opening to lock said grate in the second position.