BOILER LINER FOR OIL-OR GAS-FIRED BOILERS AS WELL AS PROCEDURE FOR THE MOUNTING OF SAME

Abstract: A boiler liner intended for improvement of combustion, reduction of smoke loss, and procurement of heat flow in existing oil- or gas-fired central heating boilers, through which the supplied heat energy is better utilized, in that by way of heat resistant material (2, 3, 6, 7, 8) the name room is upwardly confined as compared with an existing larger boiler chamber. It is according to the invention proposed that the flame limitations are designed from a highly insulating material. The high insulating capacity of the applied material will cause that the assimiluated heat is stored at temperatures almost equalling the name temperature, which will bring about that the stored volume of heat will be quickly given off by radiation after the name has been extinguished. At the same time the undesirable heat convection in the boiler chamber will fail to manifest, which in case of known flame limitations is intensified by the presence of good heat conducters and/or heat absorbing bricks. The counterradiation from the highly insulated material will cause that the interval between the sparks will be prolonged.

Description: BOILER LINER FOR OIL- OR GAS-FIRED BOILERS AS WELL AS PROCEDURE FOR THE MOUNTING OF SAME The invention relates to a boiler liner intended for improvement " of combustion, reduction of smoke loss, and procurement of heat flow in existing oil- or gas-fired central heating boilers, through which the supplied heat energy is better utilized, in that by way of heat resistant material the flame room is upwardly confined as compared with an existing larger boiler chamber. It is known from minor oil-fired boilers, with an oil consumption of about 2 kg/hour or below to place a plate above the flame and thus detain the passage of the smoke gas up through the boiler chamber and out to the chimney flue. Hereby is achieved an improved heat utilization in the boiler. Plates of the said character are found in many different constructions, and the materials consist mainly of good heat conductors and/or being heat absorbing. The plates allow a greater or smaller passage of the smoke gas through the slots established between boiler walls and plate edges. Numerous different boiler constructions result in the said plates being adapted to individual boilers with different size of slot openings, so that the smoke gas turbulence from the slot opening will assume a normal picture in the boiler chamber, and the exhaust smoke temperature will remain between 200 and 300 degrees C, answering a smoke OMPI /.. IPO ^ loss of 10 to 15 p.c. This can be described as an arbitrary and relatively great smoke loss. Even extremely modern firing plants - with or without these plates - will have a loss of supplied energy ranging about 10 per cent. The object of the present invention is to devise a boiler liner of the said character that will ensure a cleaner combustion and regulate compulsorily the heat flow in the boiler chamber, whereby the heating surfaces of the boiler are continuously kept free of soot deposits, and by way of which the supplied heat energy is conveyed optimally to the boiler water, before an appropriate volume of hot smoke gasses are let out through the chimney. This is according to the invention achieved in that the flame limitation ' is made of highly insulating material. Consisting of the described heat resistant and highly. insulating material a boiler liner is built up in the boiler chamber at a suitable height over the flame. The liner can consist of a horizontal layer of plates, resting against the heating surfaces of the boiler chamber, and of vertical upright plates likewise resting against the heating surfaces. The plates are positioned at an exact distance from the heating surfaces in a manner as to form slot openings the width of which shall be less than alf the depth of the slots. Hereby will be achieved a linear smoke gas exhaustion from the slots along the perpendicularly to the slot openings situated heating surfaces and without noticeable turbulence to heat the central section of the boiler chamber for no purpose. In practice and by laboratory examinations made by Jydsk Teknologisk Institut (Jutland Institute of Technology) at Aarhus it has been established that the boiler liner will ensure temperatures quite close to the heating surfaces after the passage of the smoke gas through the slots being about 300 degrees higher than the temperature, in the interior OMPI IPO of the remaining boiler chamber. In this manner the boiler liner will allow a complete control of the smoke loss, and make it possible - proportionally with the quality of the chimney - in each particular case to determine the minimum andOor absolute smoke loss for instance by extending the slot opening along the hind wall of the boiler chamber. By way of a boiler liner of the said description the result will be an extremely low smoke loss. It is according to the invention practical that the material is designed as a building set, easily adapted to all types of boiler chambers during mounting proceedings, for instance Vermiculite. Vermiculite, produced by the Moler Works of Denmark, is a highly insulating material with low volumetric specific heat and resistant to heat loads of about 1200 degrees C. A material of this character will besides improved combustion conditions and gas flow offer a hitherto unnoticed additional utilization of the supplied energy in thermostat-regulated boilers.Partly because the material is easily cut through, whereby a precise and ideal slot opening is attainable for the individual boiler, and partly because the reflection from the burner chamber narrowed by the material will produce to a higher extent than known by the use of already known fireproof bricks an ideal temperature around the flame of from 950 to 1000 degrees C. This will ensure a clean combustion which again will reduce the pollution from the chimney smoke substantially, and produce a desirable temperature of about 400 to 500 degrees C in the slot opening between heating surfaces and the plates, which in case of slightly sulphur containing oils will ensure improved conditions of formation of S0 3 , sulphurous acid, in the contact with the heating surfaces of the boiler. The heating surfaces will thus be kept mainly free of soot deposits. The temperature attained in the slots between the plates OMPI /.. WIPO and the heating surfaces of the boiler is conditioned by the inlet temperature of the gasses through the slots, as well as by the fall of temperature appearing during the passage of the gasses through the slots. A relative wide slot will thus procure excessive temperatures, whereas a relative narrow slot will result in temperatures unnecessarily farbelow the conversion temperature for SO„ to SO_, and accordingly too slow rate of formation of sulphurous acid. It has been proved in practice that the boiler liner during 8 to 14 days after the installation will disintegrate old firm deposits and clean the heating surfaces completely. The highly insulating effect of the materials will bring about that the assimilated heat is stored at temperatures near to the flame temperature, and cause that the stored volume of heat will be quickly given off by radiation, as the surface of the Vermiculite plates will be cindered, and it will appear that the temperature will rise comparatively more due to the said radiation when the flame is extinguished. At the same time an undesirable heat convection will fail to manifest in the boiler chamber, which by known flame limitations is strengthened by the presence of good heat conductors and/or heat absorbing bricks. The returned radiation from the highly insulating material will provide that the interval between the sparks will be prolonged, which.has been documented by laboratory research. The aggregate effect of the boiler liner will result in efficiency effect of the supplied energy of up to 96 per cent. In this' respect the boiler liner according to the invention differs completely from known flame temperature regulation methods and socalled "smoke turning plates", in which materials are • applied that produce the said heat convection -in the boiler chamber after the extinguishing of the fire. The invention relates furthermore to a procedure of mounting the boiler liner according to the invention in all types and sizes of boilers. OMPI Λ- WIPO - There are mainly two existing categories of boilers viz. cast iron boilers with heating surfaces in corrugated profile, and plate iron boilers with smooth surfaces. The boiler liner can be built up from the bottom of the boiler as a building set, as the longitudinal plates are adjusted to the depth of the boiler chamber, ahd the crosswise plates keep the longitudinal plates interlocked with the already mentioned precalculated precise slot opening at the heating surfaces. It is according to the invention advantageous that the material is suspended on metal angles 13, fastened to the rigging screws 10 distended in the upper section of the boiler. In boilers having heating surfaces with corrugated profile, the bottoms of the profile will form natural openings for the desired slot openings, when the plates are resting against the profile. In boilers with smooth heating surfaces those plates resting against the heating surfaces are provided with 2 cm deep grooves, by which the ideal slot opening has been obtained. The invention will in the following be described in detail with reference to the drawing in which . Figure 1 shows an oil-fired cast iron boiler with corrugated profiles and a boiler liner according to the invention seen in perspective from the front and in partwise section, Figure 2 shows an oil-fired plate iron boiler with smooth heating surfaces and a boiler liner according to the invention seen aslant from the front in perspective and in partwise section, and Figure 3 a boiler liner seen from the front with separate individual Darts. Figures 1 and 2 show sections of oil-fired boilers, in the foremost wall of which the burner tube of the oil burner is situated. Above the burner tube and resting on a foundation of highly insulated plates 2 shaped according to the form of the boiler is placed a layer of plates 3 » resting in boilers with corrugated profile against the heating surfaces 5 of the boiler, by which are produced slot openings 4 between the plate material an .the indentations of the heating surfaces. Upright on this layer of plates 3 can be placed two plates 6 in boilers with,corrugated profile, whereby linear hot air flow along the heating surfaces is provided. The said plates 6 and loosely placed plates 7, covering the intervals between the plates, are kept in due position by the crosswise passing adaption plates 8. In boilers with smooth heating surfaces 5, cf. Figure 2, the plates 3 of the layer to form slot opening to the heating surface 5 are provided with 2 cm deep grooves. These grooves will provide the desired slot opening 4,-when the plates 3 are squeezed against the heating surfaces. The plates 3 are kept in due position by the crosswise passing adaption plate 8. In boilers with heating surfaces with corrugated profile the liner can, as shown in Figure 3, be suspended by means of rigging screws 10, distended horizontally from side wall to side wall in the upper section of the boiler chamber. The rigging screws 10 are provided with open bends 11 of a special alloy of spring steel, and in the openings of which the angle bars 13 are suspended. The four angle irons 13 form the basis of the mounting of the boiler liner according to same principles as specified with reference to Figure 1. The horizontal bars of the angle irons 14 are coated with the same highly insulating material as that of which all the plates are made. In the shown embodiment the combustion gasses from the flame will attain an extremely high temperature in the circumference of the flame due tc the counterradiation of the plates. Hereby is secured a high quality of ' combustion. The built up and narrowed burner chamber will contribute to uphold the greater initial air velocity in the chamber, whereby the convection of the area concerned is improved, after which the heat flow at a temperature of between 400 and 500 C will continue through the slots between the plates 3 and the heating surfaces 5. Due to the socalled Coanda effect along the heating surfaces 5, the heat flow will remain in immediate contact with the heating surfaces up to the ceiling 15 of the boiler, after which the heat flow severely drained of heat energy will escape out through the flues of the the boiler into the chimney. In case the chimney of the central heating plant does not allow for the obtained low temperature of smoke, and provided it being impossible to improve otherwise the chimney conditions, the plates 3 are dismantled and shortened, so as to form a free opening to the hind wall of the boiler 16. The chimney temperature will thus be raised by about 10 degrees C for each h cm cut off the plates.

Claims: P A T E N T C L A I M S 1. Boiler liner intended for improvement of com¬ bustion, reduction of smoke loss* and procurement of heat flow in existing oil- or gas-fired central heating boilers, through which the supplied heat energy is bet¬ ter utilized, in that by way of heat resistant material the flame room is upwardly confined as compared with an existing larger boiler chamber, c h a r a c t e r i z e d i n t h t- the flame limitations are made of highly in¬ sulation material. 2. Boiler liner according to Claim 1 c h a r a c ¬ t e r i z e d i n t h a t the material is designed as a building set easily adaptable to all types of boiler chambers during mounting proceedings, e.g. Vermiculite. ' 3. Procedure for mounting of a boiler liner accor¬ ding to Claims 1 or 2 " c h a r a c te r i z e d , i n t h a t the material is suspended on metal angles (13) being fastended to rigging screws (10) distended in the upper section of the boiler. 4. Procedure according to Claim 3 c h a r a c t e ¬ r i z e d i n t h a t the material is placed.in re¬ lation to flame and heating surfaces of the boiler (5) in such a manner that such an inlet temperature fall is achieved that the temperature in the slots (4) at the heating surfaces remains between 400 and 500 degrees C. OMPI

Inventors: PEDERSEN A
Applicants: PEDERSEN A
Application year: 1980
Main classification: F22B37
IPC codes: F23M3, F24H9