Store and burn incinerating toilet and method

(54) Title: Accumulation and Destruction Incineration Toilet (56) Publications cited:

7609927-4

The invention relates to destructive combustion toilets, which are toilets where the waste is burned to ashes. For the sake of simplicity, the term combustion toilet is used. More specifically, the invention relates to a combustion toilet in which the waste is accumulated successively and the incineration takes place after a sufficiently large amount has been accumulated.

Incinerators are desirable in those cases where water toilets are impractical or in any case not as comfortable as a combustion toilet.

In known combustion toilets, combustion generally occurs after each use. Thus, after each use, a combustion cycle is started, the system being heated to a temperature of the order of 800 ° C, which of course entails considerable fuel consumption. The combustion cycle can be carried out with a fuel air ratio of 300; 1, whereby an energy amount of the order of 30 kWh is required only for heating the air. After the combustion cycle, the entire system must be cooled to a safe temperature before the toilet can be used again. This means that a fan for forced circulation is needed. Smelly debris can be blown into the environment by requiring a large volume of cooling air. In general, rather complicated electric controllers are used with interlocks and safety devices for controlling and operating such combustion toilets.

It will be appreciated that fuel consumption at such known combustion toilets is high because a large amount of fuel must be consumed only to. heat the system to the combustion temperature and to heat the excess air for each combustion cycle.

If you consider that a toilet intended for an average family of four can be used up to 45 times a day, you will readily realize that fuel consumption is a real problem.

Another problem lies in the waiting time that becomes necessary during periods of diligent use because the system must be cooled down before new use is possible or in the very strong cooling air flow required and may interfere with subsequent users. In general, the toilet must be completely exempt from use for a period of 3-4 hours per day.

It is an object of the invention to provide an accumulation and combustion toilet which does not have the disadvantages, deficiencies and other disadvantages and problems of known combustion toilets.

Further objects of the invention are to provide an accumulation and combustion toilet in which waste can be accumulated for a long time and effectively incinerated in a single combustion cycle, to provide a cheap and efficient combustion toilet which remains odorless during the accumulation period and performs combustion efficiently. , to provide a combustion toilet which, during the combustion cycle, operates with a simple, heat generating apparatus, such as an atmospheric gas burner, and simple convection features, under the pressure of the regular supply network, and making it unnecessary to use a funnel between the toilet seat and the waste container.

The stated objects are achieved with a closet of the configuration specified in the claims.

As will be apparent from the following detailed description, a plurality of waste batches are successively accumulated in a heat-permeable, upwardly open container, the upper part of which is kept closed during a combustion cycle, whereby vapors and combustion products are passed from the container through a combustion chamber under the container and finally discharged into the container. in a chimney. Preheated air is introduced into the container during the combustion cycle, and additional air to promote combustion is introduced adjacent the inlet to the flue gas duct in the chimney. During the combustion cycle is one

7609927-4 safety cover placed in locked position above the container. During the period of accumulation of the waste, an overcoating and disinfecting foam may be applied over the waste in the container. The accumulation of waste in the container can be measured, so that one can determine when a sufficient volume has been accumulated for optimum efficiency in combustion.

The invention is explained in more detail below with reference to the accompanying drawings, which show an exemplary embodiment.

Fig. 1 is a perspective view of a combustion toilet constructed in accordance with the invention;

Fig. 2 is a side view of the closet of Fig. 1, some parts being shown in vertical section for the sake of clarity;

Figure 3 is a view from line III-III of Figure 2;

Fig. 4 is a view from the line IV-IV in Fig. 2;

Fig. 5 shows a horizontal section along the line VV in Fig. 4;

Fig. 6 is a fragmentary top view showing a lid overlying the waste container during combustion, some parts being shown in horizontal section;

Fig. 7 shows on a larger scale a section along line VII-VII in Fig. 6;

Fig. 8 shows on a larger scale a section along line VIII-VIII of Fig. 6;

Fig. 9 is a fragmentary top view showing a modified embodiment of the lid;

Fig. 10 shows on a larger scale a section along the line XX of Fig. 9;

Fig. 11 is a schematic view showing the devices with which the combustion in the toilet is carried out.

The combustion toilet shown in the drawings has a housing or housing 15 which may be manufactured as a molding of a corrosion-resistant, impact-resistant and sufficiently heat-resistant thermoplastic material, for example the material marketed under the trademark LEXAN and designated FL 900 and suitable for the manufacturing process. is called TSF (Thermoplastic Structural Forming). The housing 15 has a front wall 17, opposite side walls 18 and a bottom 19. At the rear of the housing there is a hood 20 which encloses an upwardly directed exhaust duct.

Inside the housing 15 is adjacent to the front wall 17 and between the side walls 18 a heat-permeable, upwardly open container 21 into which waste is introduced through an opening 22 in a deck 23. This is preferably formed

7609927 * 4 of a shaped part of sheet metal, for example stainless steel sheet, which is so dimensioned and shaped that it fits against and can abut the upper edges of the front wall 17 and the side walls 18 in front of the lower end of the protruding hood 20. In order that the tire 23 to be kept properly aligned on the housing 15, it has a downwardly extending circumferential flange 24 which extends around the leading edge and side edges and is secured to the outside of the top of the front wall and sidewalls of the housing. An upwardly extending collar flange 25 on the tire 23 adheres to the lower end of the front wall of the cap 20. The tire 23 is held in place by screws or¹⁰ other suitable means (not shown) in such a way that it can be removed when needed. On the tire 23, and with proper alignment with respect to the receiving opening 22, rests a toilet seat 27 and a seat cover 28, which are pivotally secured to the rear of the tire 23 using hinge brackets 29 of the usual type.

In the preferred embodiment, the container 21, which may also be referred to as a pot or retort, is made of stainless steel by casting, having a front wall 30, a back wall 31, opposite side walls 32 (Figs. 2, 3 and 4) and a bottom 33. The container forms an upwardly open accumulation chamber, which is elongated in the forward direction. The bottom 33 slopes downwards and forwards at a small angle.

In order to obtain a combustion chamber 34 below the container 21, the container is removably supported at intervals above the bottom of the housing.

19th In this case, the supporting members are a metal frame with a pair of laterally spaced support members 37 having upwardly open sockets 38 for receiving downward-facing feet 39, integrally formed with the bottom of the container 33 adjacent to the transition between the front wall 30 and the side walls 32. Another pair of laterally spaced portions 40 of the frame 35 has upwardly open sockets 41 for receiving downwardly facing lugs or feet 42 on the container bottom 33 adjacent to the transition between the sidewalls 32 and the rear wall 31. At appropriate longitudinal distances, the upper edges of the container sidewalls 32 attack an the number of retaining clips 43 which are removably attached to the upper ends of vertical anchor rods 44 on the frame 35.

The combustion chamber 34, located below and in heat transfer relation to the container 21, is formed by a refractory thermal insulation, which is preferably made of fiber ceramic and comprises a bottom plate 45 supported by the frame 35 and separated by a space in the combustion chamber from the overlying bottom 33 the container and of an air space are separated from the underlying bottom 19 of the housing 15. A vertical front insulating plate 47 extending upwardly from

7609927-4, the base plate 45, has an air gap to the front wall 17 of the housing and abuts against the front wall of the container 30. Vertical side insulation plates 48 extend upwardly from the base plate 45 and abut most of the container side walls 32 and have an air gap to the housing side walls 18. At its rear ends, the side plates 48 are joined by an upwardly and rearwardly inclined insulating plate 49 which is one piece behind the rear wall 31 of the container to form a backward and upward extension 50 of the combustion chamber 34, the rear wall 31 of the container being in heat transfer relation thereto. extension.

At the upper end of the combustion chamber extension 50 there is an inlet to an exhaust duct 51 formed by a chimney 52 made of the same refractory thermal insulation comprising high melting (1360 ° C) ceramic fibers capable of being suitable for the present purpose. thickness of approx. 2.5 cm achieve glowing conditions on the surfaces exposed to the combustion heat but to retain the heat in the combustion spaces and maintain an acceptable cold exterior, so that conduction-cooled air or dead air spaces between the insulation and the housing or housing ensure a completely safe and comfortable temperature at the exterior surfaces of the house. Heat transfer to the outside of the housing is further reduced by the housing being made of a material with poor heat transfer capacity. There is a relatively large gap between the chimney 52 and the hood or housing 20, in particular the removable rear wall 20a of the housing, which closes the housing rearwardly and extends from the bottom of the housing 19 up to or at least forms an inlet opening 53 through which combustion and cooling air can flow. in the device. A tubular hood 54 is mounted around the upper portion of chimney 52 and has a gap therebetween. The hood 54 is open at the bottom to receive cooling air, and its upper end is closed and has a side projecting outlet socket 55 which leads from the hood and extends outwardly through the aperture 53, where it can be connected to an evacuation tube or the like. outside the hood 20. A support or bracket 56 for the chimney is supported by the drawbar 54, which in turn is suitably secured to the inside of the front wall of the hood 20. An outlet port 57 is formed in the upper part of the chimney 52 opposite the outlet socket 55. By this arrangement, relatively cool air will be sucked through the hood 54 into and cool the clean exhaust gases flowing through the gate 57. It should be noted that the flow cross-sectional area of ​​the socket 55 is considerably larger than that of port 57, whereby the socket can transport the increased volume resulting from mixing cooling air with the exhaust combustion gases.

Below deck 23 is a thicker layer 58 of refractory insulation material, which is supported over the top of container 21. This insulation layer 58 may be of substantially the same material as the insulation forming the combustion chamber 34, the combustion chamber extension 50 and the afterburning chimney 52, but may have a more porous or woolly structure and be approx. 4 cm thick. A hole 59 in the insulation layer 58 is opposite and forms a small clearance to a downwardly directed flange 60, which has a width approximately equal to the thickness of the insulation layer 58 and forms the receiving opening 22 in the tire 23 while shielding the edge of the insulation layer 58 formed by hole 59, in that the downwardly directed shield or guard flange 60 is as narrow as possible, i. no wider than the insulation layer 58 is thick, and is substantially straight and vertical, the contamination risk is minimal.

During the use or accumulation or storage period, the receiving port 22 should be open so that the toilet can be used in the usual manner, and no flushing or combustion is required after each use, but only after so much has accumulated in the container 21 that it is justified to carry out a combustion cycle. For example, the capacity may be such that the toilet can be used 65-70 times, or the accumulation can take place until the accumulated waste reaches a predetermined level, which can be indicated by a measuring or marking device. Such a device is formed in the illustrated embodiment by a vertical measuring strip 61 (FIG. 2, 3 and 4), which is mounted on one of the walls of the container 21, namely the rear wall 31, and extends from the bottom 33 to the maximum height, and by looking through the opening 22 it is possible to determine when the maximum level has been reached. In FIG. 2 the waste 62 is shown to have reached the upper end of the measuring strip 61, which means that a combustion cycle should be started, but in practice it may be appropriate to start the combustion cycle even when the container is filled to a lesser or even slightly greater extent than corresponding to the position of the upper end. of the measuring list 61.

During the accumulation period, an aesthetically and sanitally suitable foam cover layer 63 may be applied over the waste 62. This foam may be applied in any suitable manner, for example by means of an automatic device introducing the foam into the waste container, but it may be economically more advantageous to apply the foam.

7609927-4 manually from a suitable container, such as a spray can, when needed to conceal the waste and prevent bad odor. A fairly stable but non-combustible foam for this purpose may comprise a soap compound of fatty acid and contain a durability enhancing agent such as zinc sulphate, a bactericidal agent and a perfuming agent. For the foam to be conveniently applied, it can be stored in a dispensing container pressurized with a conventional propellant such as aerosol, isobutane, propane or the like.

Prior to starting a combustion cycle, the receiving orifice 22 is sealed and sealed by a security closure 64 (see Figs. 6, 7, 8 and 11). The security closure 64 has a preferably metal-made top plate 65 to which a suitable protruding handle 67 is attached. On the underside of the top plate 65 there is a generally cup-shaped body 68, the circumference of which fits freely within the flange 22. The cup body 68 is joined to the top plate 65 by a laterally projecting edge flange 69 which is secured to the edge of the top plate 65 which is so dimensioned as to cover the tire 23 around the opening 22. An insulating gasket 70 is attached to the underside of the flange 69 for to form a heat seal. Inside the chamber formed by the bowl body 68 is a suitable thermal insulation 71. In order not to accidentally displace the closure 64, one or more locking fingers 72 are secured to the underside of the bowl body 68 along a side edge and arranged to grip the lower edge of the flange 60, and furthermore there is a manually slidable locking pin 73 which is disposed inside the bowl body. 68 to extend at the opposite side through a hole 74 into a tubular socket 75, which is supported by the flange 60 and extends into and through the adjacent portion of the tire insulation plate 58. The locking pin 73 is supported by a guide tube 77 which is held by a bracket 77 at a suitable distance below the top plate 65. The locking pin 73 can be displaced by the same fixed, projecting handle 79 extending through a slot 80. This slot limits the displacement of the locking pin 73 to a retracted end position, in which the outer end of the locking pin is in the open position relative to the outside of the closure at the hole 74, and an extended end position in which the locking end of the locking pin is inserted far into the socket 75. The handle 79 through an opening 81 formed above the slot 80 in the top plate 65.

In order that the closure 64 cannot be opened after a combustion cycle has proceeded to a dangerous temperature in the holder 21, there is an interlock acting on the temperature, which includes a safety closure plate 82. This is slidably supported by holder 83 on the underside of the top plate 65, it being normally adjacent to one side, in this case the rear side, of the opening 81 but, depending on the temperature, the opening and closing position of an opening 81 is displaced. The temperature dependent displacement of the plate 82 provides a bimetallic strip 84, the center portion of which is fixed at the trailing edge of the plate 82 and whose opposite end portions extend freely slidably through holes 85 in the mount 78. At room temperature, the bimetallic actuator 84 holds plate 82 in the retracted position marked by dashed lines in Fig. 6. When the temperature in the container 21 reaches a predetermined level, e.g. 80 ° C, plate 82, under the influence of bimetallic actuator 84, is displaced to the fully blocking position shown by solid lines in Fig. 6. This blocking position remains until the unit has cooled down to a safe temperature, the back plate 82 being actuated.

In addition to its locking or locking function, the locking pin 73 fulfills the function of operating a burner safety device in the form of a normally open blocking switch 87, which is mounted on a bracket 88 on the side wall 18 adjacent the locking pin 75 of the locking pin. This switch 87 may be of the microswitch type and has a spring-loaded actuating arm 89, the outer end of which is articulated to the outer end of a slidable actuator 90, which projects into the tubular socket 75 and is arranged to displace in the direction of the actuator's arm 89. when the locking pin 73 is moved to the locking position and to be returned under the action of the arm 89 when the locking pin 73 is retracted. The burner control circuit is thus automatically broken when the locking pin 73 is retracted and automatically closed when the locking pin is moved to the locking position.

In the modified embodiment shown in Figs. 9 and 10, the locking pin 73 operates and is operated in the manner described above. Instead of plate 82, in this case, the closure means 64 has a plurality of automatically operated, depending on the temperature, locking pins 91, each of which is connected to an actuator 92 in the form of a bimetal strip mounted on the fasteners 93 on the top of the bottom of the bowl body 68 . Conveniently, there are three such latching pins 91 which are disposed one at each of the opposite sides and at the rear edge of the closure means 64. The latches are projected from the associated side of the closure means 64 under the influence of actuation 9.

7609927-4 means 92 for locking engagement with a hole 94 in the tire flange 60. Although the locking pin 73 can be retracted and the burner control circuit opened before the unit has cooled to a safe temperature, the closure 64 can thus only be opened when the locking pins 91 are retracted.

When the waste 62 accumulated in the container 21 is to be incinerated, heat is supplied to the combustion chamber 34 and its extension 50.

Running this object there is a selectively operable heat generating device in the form of a gas burner 95 which is arranged in the combustion chamber below the container 21. In the preferred embodiment, the burner 95 is of the so-called the atmospheric type, which operates quietly at ordinary feed pressure and is essentially a tube supported on the insulation bottom plate 45, an outer end portion 97 of this tube extending outwardly through a generally vertical elongated keyhole slot 98 in a removable slot 99 in the lower the portion of the rear insulation board 49 and adjacent to one side (Figs. 2 and 5). Run to provide maximum low generation with a simple and effective geometric configuration, burner 95 has a winding or curved shape, exhibiting a generally diagonal section 100 extending obliquely from the straight end portion 97 and substantially forward from one side toward the the opposite side below the bottom 33 of the container 21 to enter a reciprocally curved section 101 leading to an elongated inner cross section 102, lying beneath the front portion of the bottom 33 at the deepest portion of the container 21, i. where the waste has the greatest depth. Along the upper edge of the tubular burner 95 are a plurality of low apertures 103, which are preferably equal in size and spaced apart. At its inner end, the burner is closed, and at its outer end, it is open and connected to the discharge end of a gas supply line 104, passing a substantially U-shaped air gap piece 105 which holds the discharge end concentric with the open inflow end of burner section 97. a portion of the burner section 97 passing through the opening or slot 98 leads a series of spark plug openings 107 to the beginning of the series of larger low openings 103. The number of low apertures 103 over the burner distance from the inner end of the row of ignition openings 107 to the center of the curved burner section 101 is conveniently sufficient to provide a heat generation of approx. 9 kWh (34000 kJ) at full operation of the burner, and the number of openings 103 from the center of section 101 to the end of section 102 is suitably sufficient to provide a heat generation of approx.

7609927-4 kWh (24000 kJ), ie total approx. 15 kWh (58000 kJ), sufficient for complete combustion of a waste accumulated in 45 applications of approx. 1.5 hours or an accumulated amount of waste of about 65-70 uses. 3 hours.

A device for controlling burner 95 comprises a simple electromechanical device, which is best shown in Figures 1, 2, 4 and 11. The device comprises a timer switch 108 electrically coupled to a valve switch 109, which may include an electromagnet for operating the a gas control valve 110 in a gas mains line 111 which is connected to the supply line 104 during mediation of a burner control unit 112. After the closure means 64 has been placed in the closure position and the interlock switch 87 has been closed, the burner 95 can be started, which is done by manually switching the timer 108 by turning a knob 113 until a pointer 114 on the knob points to the desired combustion time on a scale 115. the gas valve 110 is opened, which is then closed again when the time switch has measured out the set time. When the valve 110 is opened, the gas arrives at the burner control unit 112. When a switch push button 117 is pressed into an auxiliary ignition system, an auxiliary nozzle 118 gets gas, and a piezoelectric auxiliary igniter 119 is actuated by pressing a switch button 120. 104 so that burner 95 is supplied with gas. The burner is lit by the auxiliary lighter 119 ignites the gas at the ignition openings 107, after which the gas exiting through the openings 103 is ignited. A suitably placed, normally closed thermal safety switch 122 is opened and stops the combustion cycle if the temperature inside the closet becomes too high, for example due to some malfunction or if the timer 108 has been set for a longer time than is needed for complete incineration of the waste in the container.

Naturally, primary combustion air is supplied directly to burner 95 at connection piece 105. A greater volume of secondary combustion air is supplied through an air passage 123 provided in preheating relationship to the combustion chamber, more specifically, the combustion chamber extension 50, which surrounds the air duct 124 with the interior of the container 21 through the upper portion of its rear wall 31. The secondary combustion air removes boiled steam from the container 21 through means which force the steam and any combustion generated in the container to pass into the combustion tank 34 and along the heat generating apparatus, ie. burner 95, towards the exhaust duct 91. For this purpose, the upper front portions of the container side walls 32 are formed with outflow apertures 125 leading to suction ducts 127 (FIG. 3, 4 and 5), formed by offset portions of the front portions of the insulation side plates 48 in association with the portions below the ports 125 of the front portions of the container side walls 32. At its lower ends, suction channels 127 communicate with the front end portion of burner 34 in the vicinity of burner section 102 and in front of burner sections 100 and 97. Conduits created by the action of burner 95 cause the secondary combustion air to be sucked in through passage 123 to evaporate waste material from container 21 through ports 125 and passageways 127 into the front portion of burner chamber 34 and along burner 95 over the holes emitted from holes 103 in the flow path. The secondary air causes a significant increase in the combustion intensity and ensures a maximum conversion of the waste material into primary gaseous constituents. At the combustion chamber demand 50, tertiary combustion air is supplied through an inlet formed by one or more ports 128 arranged in the lower portion of the rear wall 48, preferably immediately above the door 99. The thus supplied air and any air leaking through the free space at the burner feed opening 98 intensifies the combustion and improves the convection pull towards and into the exhaust duct 51. Maximum efficiency is achieved by centering the inlet 128 as low as practicable at the inlet to the combustion chamber extension 50 and centering under the secondary air drum 124 located in the upper portion of the combustion chamber extension 50, where maximum preheating of the secondary combustion air is achieved. It will be appreciated that since the combustion heat rises gradually during the combustion cycle with a proportional increase in the convection rate, a substantially proportional secondary air preheating is of great advantage in increasing the rate at which the waste material in the container 21 is incinerated.

Another important advantage of intensifying combustion in the combustion chamber extension 50 lies in the post-combustion of residues that occur in the exhaust duct 51. The intensive combustion activity causes the internal surfaces of the chimney 52 to become glowing, and the upward current is exposed to an intense reflected heat, which fully the destruction of any unburned components that escape the combustion chamber. At the outflow port 58 in the upper part of the chimney .12, the outflow is in the form of an air-free gas.

During the combustion cycle, initial boiling and evaporation of the liquid content of the waste takes place. Since the normal ratio of solids to liquid substances in latrine is in the range of 1: 4 to 1: 6 or approx. 1 kg of solid material on 8-12 liters of liquid, the combustion cycle is absorbed by a rather long period of boiling in the container 21, during which the solid is broken down into a slurry of finely divided particles. When all liquid is boiled away, the solid waste reaches the flash point, after which incineration takes place directly in the container 21 until the solid waste is completely consumed. The combustion of the solid waste is promoted and becomes efficient through the atomization that the boiling entails.

Data collected with automatic recording equipment shows that during a combustion cycle during which the container contents are burned, a rapid increase in temperature is first performed, which is important in avoiding bad odor from the chimney at the start.

A temperature of approx. 650 ° C is reached very quickly, which gives an extremely good odor elimination. The various operating parameters, such as the number and location of the gas supply, the supply of primary, secondary and tertiary air, the location of the container 21 in relation to the burner 95, the size and arrangement of the combustion chamber 34, the length of the afterburning exhaust duct and the glowing areas of the refractory bed, to produce a substantially uniform and stable result. As the evaporation of the liquid waste increases, the increased convection absorbs cooling air in the system and this results in maintaining a fairly stable temperature, which at its height decreases slightly at maximum boiling. However, the combustion rate is easily controlled by adjusting the fuel supply in such a way that the temperature is kept high enough to avoid smelly gases from the chimney. Therefore, during the boiling, a fairly small temperature change occurs, and the system operates in a substantially stable state. After the evaporation has been completed and the remaining solid combustible waste has been heated to the flash point or ignition temperature, it ignites, but this does not result in any significant increase in the temperature of the system except for a short-term increase just at the time of ignition. When the heat generated by the ignition of the waste material is added to the heat supplied by the burner, the increased convection rate results in an increased air inflow through the secondary and tertiary inlets, the secondary air inlet allowing a generous air supply and the tertiary inlet to allow for more wherein by the combustion temperature in the system, the temperature is kept substantially constant without the need to modulate the fuel supply to the burner 95. For example, good results have been obtained with a cross section for the secondary air passage 123 of approx. 65 cm and a cross section of the ter2 tertiary air inlet 128 of approx. 28 cm .1 such unit is a suitable length of the exhaust duct 51 approx. 95 cm, and a suitable cross-sectional area is about 100 cm.

If the timer switch 108 has not yet expired and stopped the combustion cycle when all the waste has been incinerated in the container 21, the safety switch 122 will respond to a slightly smaller increase in the temperature of the unit, interrupting the burner control circuit, thereby interrupting the combustion cycle. The remaining heat in the system will continue the convection circulation, so that air sucked in through the secondary air inlet 123 and the tertiary air inlet 128 speeds up the cooling. When the heat sensing, bimetallically operated safety interlocks for the closure 64 have taken inactive or free position, the closure can be removed from the receiving port 22, after which the toilet can be used again.

A major advantage in terms of compactness, economy and usability lies in the fact that the toilet does not need a funnel to guide waste material from the opening 22 into the container 21. This eliminates an inconvenience in most dry-type closets and also in the water-flushed conventional toilet funnels that become unhygienic and often contaminated with dry waste or waste that stubbornly resists cleaning attempts. In the closet according to the invention, the upper edges of the container walls are adjacent to the underside of the insulation plate 58 of the tire, and the vertical tire flange 60 is only a stiffening and insulating protective flange which forms the opening 22 and is very little exposed to contamination. The surfaces inside the container 21 are automatically cleaned during the combustion cycle. In this context, the front wall 30 performs an important function as splash protection, which avoids, for example, urine contamination of the front insulating plate 47, which is thereby protected from the degrading effect of organic salts and consequent deterioration of the insulation properties. The ports 125 are indeed located in the front portions of the sidewall 32, but they are far enough away from the opening 22 and high enough not to be reached by splashing.

A valuable feature of the fiber-ceramic insulation that is directly exposed to the heat of the combustion chamber and chimney is that it is not only a very effective, lightweight, refractory insulation but

7609927-4 also thanks to its relatively coarse structure gives an increased surface area for annealing radiation. Another advantage of this insulation is that the relatively coarse surfaces produce turbulent rather than laminar flow in the boundary layer, which obviously improves the mixing of the vapors and the combustion gases with the hottest area of ​​the combustion zone towards the center of the combustion flow path through the unit and thereby contributes to effective.

7609927-4