Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/0005—Details for water heaters
  • F24H9/0036—Dispositions against condensation of combustion products
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
  • F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
  • F24H1/24—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers
  • F24H1/26—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body
  • F24H1/28—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes
  • F24H1/287—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes with the fire tubes arranged in line with the combustion chamber

Definitions

• the invention has for its object to provide a method for firing a boiler, in which a condensation of combustion gases on the boiler wall is avoided regardless of the boiler wall temperature.
• combustion exhaust gases flow through the boiler in a laminar manner in the contact part and the dynamic pressure of the flow is at least 3 mm WS, preferably 6-10 mm WS.
• Another major advantage of the invention is that without additional internals, such as vortex generators od. Dg]., The heating surface required to achieve a certain exhaust gas temperature can be reduced compared to the conditions necessary in known Feuerungsver conditions.
• Another advantage of the invention is that the running noise of the boiler is greatly reduced compared to known combustion processes. So can in boilers operated in the manner according to the invention on Abijasscha 11 dampers which are connected downstream of the boiler, or soundproofing hoods which surround the burner are largely dispensed with.
• heat transfer numbers of 30 to 40 kcal / m 2 h ° C can be achieved, corresponding to Reynolds numbers from 5000 to 10000, the laminar flow at Reynolds numbers between 1000 and 1500 heat transfer coefficients from 100 to 150 kcal / m 2 h ° C, i.e. three to four times the values.
• the heating surface can be reduced in a corresponding ratio.
• a practical example showed that on a heating boiler operated according to the method of the invention, 19 cm flow path of the combustion exhaust gases in the contact part were sufficient to cool the temperature of the exhaust gases from approx. 900 ° C to 65 ° C, at an inlet temperature of the boiler water of 11 ° C and an outlet temperature of 22 ° C.
• the dew point of the combustion gases was approx. 55 ° C.
• the temperature of the walls of the contact part was, as usual, a few ° C above the water temperature. Nevertheless, the entire heating surfaces of the contact part remained completely dry and free of condensation, while the downstream exhaust pipe, in which the combustion exhaust gases flowed turbulently and with low back pressure, showed strong droplet condensation. Of course, under practical conditions you will never work with such low exhaust gas temperatures.
• the contact part of a boiler which is to be fired in the manner according to the invention can have any shape, provided that the process conditions mentioned with regard to the Reynolds number characterizing the laminar course of the flow and with respect to the dynamic pressure are met. So the flow cross-sections as tubes of round or other cross-section, as a flat column or annular gap and the like. be carried out.
• the flow path should preferably be straight or only moderately curved in the limit case. Sharp deflections that could disturb the smooth laminar flow should be avoided. This also makes sense from the point of view of energy consumption.
• Each curvature of the flow path accordingly results in an additional flow contradiction without, in contrast to the turbulent flow, causing a correspondingly increased heat transfer.
• a stainless material will be chosen in practice for the walls of the contact part, in order to prevent rust particles from forming due to the atmospheric moisture during prolonged downtimes of the boiler, which could favor condensation.
• material No. 1.4578 is suitable.
• the walls should have a sufficient thickness, in particular to ensure the necessary dimensional stability, at least 4 mm, preferably 6 to 8 mm.
• the dynamic pressure along the flow path decreases in accordance with the cooling of the combustion exhaust gases.
• the Accordingly, the dynamic pressure must be sufficiently high at the entry into the contact part.
• it is more advantageous because it is more economical to dimension the cross section of the flow path at the contact part in such a way that there is a constant along the flow path
• FIG. 1 shows a first embodiment of the invention
• 2 shows a second embodiment of the invention
• FIG. 3 shows a third embodiment of the invention.
• Fig. 1 shows a boiler for hot water production with a burner in longitudinal section.
• a preferably cylindrical furnace 1 with a diameter D and an axial length L is surrounded by water 2.
• the combustion chamber 1 is closed at one end by an end wall, and at the other end there is an opening 3 through which the burner flame is introduced centrally along the axis.
• the flame jet flows along the axis to the opposite wall of the combustion chamber 1. There they deflect outwards in a known manner and flow back along the walls of the combustion chamber 1 to the outer zone of the insertion opening 3, where they then pivot radially outwards and into the contact part 6 occur.
• This contact part 6 is formed from predominantly radial, water-cooled walls 4 and 5, which consist of material no. 1.4578 with a thickness of 6 to 8 mm.
• the flow cross section of the contact part 6 located between them decreases towards the outside in such a way that there is constant dynamic pressure along the flow path in the contact part 6.
• the exact distance between the walls 4 and 5 is secured by spacers 7 attached to discrete locations, which can be spacer rings around bolts, for example.
• spacers 7 attached to discrete locations, which can be spacer rings around bolts, for example.
• the water cooling of one wall of the contact part 6 can also be dispensed with. This then assumes an equilibrium temperature in a known manner and radiates its heat onto the opposite water-cooled wall. However, this increases the heating surface requirement by approx. 40%.
• the wall 5 cooled with water 2 is designed as a boiler door, which is sealed by a seal 8 against the outer wall of the exhaust gas collecting space 9. You can reach this
• An exhaust pipe 10 connects to the exhaust gas collecting space 9 in a known manner.
• the walls 4 and 5 extend substantially radially. They can also both be designed to be more or less strongly conical, as a result of which the exhaust gas collecting space 9 is, for example, moved further towards the exhaust gas outlet. Likewise, the exhaust gas collecting space 9 can be designed differently.
• the formation of the walls, especially the wall 5 of the contact part facing away from the combustion chamber 1 has the advantage that when the same is removed, ie when the boiler door is opened, the entire touch heating surface is freely accessible for inspection and cleaning. Cleaning is then easily possible without special tools.
• Spray hole 15 through which an injection nozzle 16 blows heating oil into the combustion chamber 11 in a known manner.
• the injector 16 can be replaced with a gas pipe of the same outside diameter in gas firing.
• the fuel is ignited in the usual way by electrodes 17.
• the combustion air and possibly heating oil are supplied in a known manner from a blower motor unit 18.
• the combustion air first reaches a space surrounding the combustion chamber 11 Housing and enters the vane ring 13 from there. It is advantageous if the guide blades have a certain angle with respect to the circumferential circle surrounding them. You then give the combustion air in addition to a swirl also a certain axial component, so that it is guided along the wall 12 in a stable spiral flow.
• a collar 19 can be connected to the combustion chamber 11, which improves the mixing of the fuel gases and prevents the ejection of larger drops in the event of nozzle malfunctions. It is followed by a divergent acceleration nozzle that accelerates the burning flame gases to speeds of 50 to 80 m / s. These emerge from the outlet opening 21 of the acceleration nozzle 20.
• burners of known design can also be used, preferably those with the highest possible flame jet speed and the highest possible flame stability, provided that a somewhat higher running noise of the boiler can be accepted. It should be emphasized that, however, there are still thin running noises that are noticeably below the running noise of conventional boilers.
• FIG. 2 shows a further embodiment of the invention, which is largely identical to that shown in FIG. 1 and is correspondingly provided with corresponding reference numerals, but in which the gap-shaped contact part is replaced by a number of radially arrayed tubes 4 ′, which are located in the exhaust gas collecting space 9 end up.
• Fig. 3 shows another arrangement according to the invention of the contact part arranged as a tube bundle.
• the pipes 4 "are placed as a bundle parallel to the end of the combustion chamber 1 opposite the burner.
• the combustion exhaust gases flow through the cross section 6" of the pipes, which in this case is constant along the flow path.
• the cross sections of the tubes are therefore selected according to the known rules of technology so that there is a laminar flow at the inlet of the tubes and that at least a back pressure of 3 mm WS, preferably 6-10 mm WS, is present at their outlet.
• the pipes pass back into the exhaust gas collection space 6.
• Axial length of the acceleration nozzle 20 110 mm
• Diameter of the outlet opening 21 of the acceleration nozzle 20 68 mm ⁇
• Collar 19 68 mm ⁇
• Circumferential circle 6 - 15o, preferably 20o.
• Range can be covered. This is made possible by the fact that by changing the spacers 7, the flow cross-section of the contact part 6 and thus its pressure loss as well as the exhaust gas temperature can be adapted to the respective power and the desired operating conditions. To switch to other operating conditions, the spacers 7 are simply exchanged for those of a different thickness, which can be done particularly easily if the spacers 7 are rings around the bolts with which the outer wall 5 of the contact part 6 is fastened to the boiler structure. In this way, the boiler can be easily adapted to different outputs, operating conditions and chimney heights.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Combustion Of Fluid Fuel (AREA)

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• 1979
  • 1979-10-29 DE DE19792943590 patent/DE2943590A1/de active Granted
• 1980
  • 1980-10-28 WO PCT/DE1980/000162 patent/WO1981001187A1/de not_active Application Discontinuation
• 1981
  • 1981-05-04 EP EP19800901934 patent/EP0038332A1/de active Pending

Non-Patent Citations (1)

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