Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
  • B65G25/00—Conveyors comprising a cyclically-moving, e.g. reciprocating, carrier or impeller which is disengaged from the load during the return part of its movement
  • B65G25/04—Conveyors comprising a cyclically-moving, e.g. reciprocating, carrier or impeller which is disengaged from the load during the return part of its movement the carrier or impeller having identical forward and return paths of movement, e.g. reciprocating conveyors
  • B65G25/06—Conveyors comprising a cyclically-moving, e.g. reciprocating, carrier or impeller which is disengaged from the load during the return part of its movement the carrier or impeller having identical forward and return paths of movement, e.g. reciprocating conveyors having carriers, e.g. belts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23H—GRATES; CLEANING OR RAKING GRATES
  • F23H3/00—Grates with hollow bars
  • F23H3/02—Grates with hollow bars internally cooled
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23H—GRATES; CLEANING OR RAKING GRATES
  • F23H7/00—Inclined or stepped grates
  • F23H7/06—Inclined or stepped grates with movable bars disposed parallel to direction of fuel feeding
  • F23H7/10—Inclined or stepped grates with movable bars disposed parallel to direction of fuel feeding rocking about their axes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23H—GRATES; CLEANING OR RAKING GRATES
  • F23H9/00—Revolving-grates; Rocking or shaking grates
  • F23H9/08—Revolving-grates; Rocking or shaking grates the bars being rocked about their longitudinal axes

Definitions

• the present invention relates to a grate intended to equip a boiler hearth or an incineration oven making it possible to burn all types of solid combustible or semi-combustible materials, and in particular various waste and mixtures such as: wood, textile, papers, straw, household waste, supermarket waste, agricultural biomass, industrial waste, etc.
• combustion grates constituted by rotary bars with integrated air blowing which have the advantage of simultaneously ensuring a double function:
• the grid according to the invention is inspired by this type of grid in its initial design, but while benefiting from the basic advantages, is characterized by aptitudes for new functions, by a certain simplicity of design, and by a reliability and a increased operational safety.
• Figure 1 schematically shows a plan view of the grid consisting of a set of identical bars (1), with horizontal axes, juxtaposed parallel, and resting on two running rails (2) located at the ends.
• the bars of circular section are joined together at their ends by large chain links (3) to thus form a train of bars.
• the pitch of the chain produced according to FIG. 1 corresponds to the distance between the bars.
• the ends of the two chains are connected to two lifting beams (4) connected to two hydraulic or pneumatic single or double acting cylinders (5) coupled together. This makes it possible to carry out a regular back and forth movement of the train of bars on the two support rails (2).
• the approximate dimensions of a bar can be of the order of 3 meters in length and 0.3 meters in diameter.
• Figure 2 shows in elevation and in section the end of a bar which can be made hollow and in this case the combustion air will be distributed by a collector (6) which can be fixed or mobile, the air being introduced at the end of each bar by means of a double sonic cone (7).
• the principle of the sonic cone consists in the manner of a venturi to increase the speed of the air passing through a duct by a progressive reduction of the passage section, in order to create a dynamic pressure effect in the longitudinal direction of the bar thus decreasing static pressure being exerted transversely and consequently the importance of air leaks.
• This system thus has a double advantage; on the one hand, to use the dynamic pressure effect to distribute the air more uniformly over the entire length of the bar, particularly in the theoretically disadvantaged central part; and on the other hand to make a non-sealed proximity connection between the movable bar and the fixed collector.
• connection between the bar (l) and the chain links (3) consists of a hub fitted with a wear ring (8) with high temperature friction resistance.
• Figure 3 shows in section the current section of a bar whose external profile is similar to that of a ratchet wheel, which has teeth (9) and in the case of a hollow bar of the blowing orifices (l ⁇ ) alternately and uniformly distributed over the entire periphery of the bar.
• FIG. 4 represents a longitudinal section of the bar with a regular toothing profile but not rectilinear so as to limit the risks of jamming by possible foreign bodies.
• the present invention based on the principle described above includes all of the following design variants, the adoption of which will depend on the overall size of the equipment, the type of material to be burned, the manufacturing technique, the quality of the materials used. work, and the automation or not of the device:
• the assembly of the bars (l) constituting the bar train can be carried out in any other way instead of the chain link system defined in Figure 1, provided that the bars can always rotate on themselves according to their main axis.
• the movement of the train of bars must be carried out only by traction or compression of the assembled assembly.
• the bearing support rails (2) can be increased in number, supporting all of the bars or even groups of bars by first defining treads (ll) assigned to each bar or each group of bars according to the example of the sketch defined in figure 6.
• the bearing support rails (2) can be positioned horizontal or in an inclined plane according to the example of the sketch defined in FIG. 7, while maintaining the axes of the horizontal bars, and in this case the movement back and forth from the train of bars may be produced by means of a single assembly composed of a lifting beam (4) and a jack (5), the assembly being situated on the highest side of the train of bars.
• the return movement of the bar train can be carried out naturally by gravity under the effect of the weight of the bar train. In the event, for example, of insufficient inclination of the support rails (2), the return movement may be accompanied by a system with one or more springs (12) or any other hydraulic or pneumatic mechanical means producing the same effect.
• the bearing support rails (2) instead of being fixed may be movable according to the sketch defined in FIG. 8, mounted on sliding pads or rollers (13) mounted idly around their axis, the rails being able to be moved along their longitudinal axis in the same way as the chains (3) using the same devices as those described above.
• the ends of the two chains making up the train of bars will be connected to a fixed frame and the movement of the rails will make the bars rotate on themselves without moving the train of bars.
• the lifter (s) (4) can be deleted and in this case the jacks (5) will be connected directly to the ends of the two chains (2), the action of the jacks needing to be coupled and coordinated so as to obtain the movement desired from the train of bars.
• the cylinder (s) (5) used may be single or double acting combined or not, provided that one wishes to maintain a tension or a permanent or untimely compression on the two chains (3).
• the jacks may be hydraulic or pneumatic and replaced by any pneumatic or electric mechanical device producing a similar linear linear translational movement of the train of bars.
• the bars can be either full or hollow, depending on whether one wishes to supply combustion air above or below the grate via an independent air distribution network, or through the interior of the bars themselves.
• the grid according to the invention in addition to certain and well-known advantages linked to the technique of rotary bars; such in particular the improvement of the behavior of the materials thanks to the cooling provided by the circulation of air inside the bars, as well as a very uniform distribution of the combustion air; has many unique features.
• the asymmetrical external profile of the teeth as shown in Figure 3 allows thanks to a jerky back and forth movement of the train of bars, on the one hand by a chopper effect to grind the bottom ash which usually tend to form a hard layer difficult to evacuate at the same time as the ashes through the bars, and on the other hand by a treadmill effect to ensure the progressive displacement at the top of the train of bars of any incombustible foreign bodies, up to their evacuation at the end of the grid.
• the uniform cross-section of the bars makes it possible to avoid any angular positioning with respect to each other, and to allow for safety deviations in rotation in particular by the play of the sliding of the bars on the rails, and thus to avoid to constantly have the same bar surface exposed to fire and abrasion. This will help to significantly increase the longevity and life of the bars.
• Another advantage of the train of bars lies in the ease of extracting for repair or maintenance the entire grid by simple rolling on the two support rails without the addition of an additional device.
• the introduction of air inside the bars is carried out at high speed thanks to a sonic cone placed at each end of the bar.
• the ash removal is ensured by a movement back and forth quite fast and more or less frequent depending on the evolution of combustion, the nature and characteristics of the waste burned.
• the grid surface can be easily modified by adding or removing one or more bars, for example using chain links.
• the method which consists in assembling the bars by means of a system composed of chain links is advantageous at the start given the high temperatures encountered or any rigid element of great length is to be avoided because of the risk of deformation.
• the operating clearance between two bars which may possibly be defined and adjusted according to the nature of the fuel burned, can be permanently adjusted by modifying the length of the chain links used.
• a play between the bars can also be usefully carried out in an untimely manner, so as to ensure a regular release of the train of bars by simple variation of the space available between the bars.
• a simple technical modification consists in making chain links with non-circular but oblong holes in the form of horizontal light forming a hub into which the circular axes of the bars are introduced according to the sketch defined in FIG. 5.
• This modification makes it possible, thanks to a simultaneous traction / compression action at the ends of the chains of the train of bars, to modulate the space available between the bars, thus facilitating the passage of foreign bodies through the grid.
• This obviously requires in automatic operation a coordination of the action of the jacks.
• the movements can be ensured with great reliability by means of jacks connected to the two lifting beams and controlled by a hydraulic or pneumatic group, thus authorizing the installation of a complete automation by means of a servo and / or any programming.
• the combustion grate according to the invention has, in addition to a very moderate manufacturing cost, a large number of advantages, while using a mechanical and hydraulic system of great simplicity adapted to the difficult ambient conditions of high temperature and abrasion. imposed by the combustion of various wastes.
• the air blowing can be carried out independently under a train of solid bars.
• shape of the toothing in particular the number of teeth, can be modified.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Gasification And Melting Of Waste (AREA)
• Solid-Fuel Combustion (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9419291

Family Applications (1)

Country Status (4)

Families Citing this family (5)

Family Cites Families (3)

• 1991
  • 1991-11-25 FR FR9114512A patent/FR2684170B1/fr not_active Expired - Fee Related
• 1992
  • 1992-11-24 EP EP93901763A patent/EP0663054A1/de not_active Withdrawn
  • 1992-11-24 CA CA 2124317 patent/CA2124317A1/fr not_active Abandoned
  • 1992-11-24 WO PCT/FR1992/001088 patent/WO1993011389A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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