US3638622A - Return flow boiler - Google Patents

Return flow boiler Download PDF

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Publication number
US3638622A
US3638622A US25622A US3638622DA US3638622A US 3638622 A US3638622 A US 3638622A US 25622 A US25622 A US 25622A US 3638622D A US3638622D A US 3638622DA US 3638622 A US3638622 A US 3638622A
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US
United States
Prior art keywords
flame
flue tube
tube
return chamber
outlet
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US25622A
Inventor
Nils Axel Ambjorn Ostbo
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Goetaverken Angteknik AB
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Goetaverken Angteknik AB
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Application granted granted Critical
Publication of US3638622A publication Critical patent/US3638622A/en
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Expired - Lifetime legal-status Critical Current

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    • 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
    • F24H1/285—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 alongside the combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B9/00—Steam boilers of fire-tube type, i.e. the flue gas from a combustion chamber outside the boiler body flowing through tubes built-in in the boiler body
    • F22B9/02—Steam boilers of fire-tube type, i.e. the flue gas from a combustion chamber outside the boiler body flowing through tubes built-in in the boiler body the boiler body being disposed upright, e.g. above the combustion chamber
    • F22B9/04—Steam boilers of fire-tube type, i.e. the flue gas from a combustion chamber outside the boiler body flowing through tubes built-in in the boiler body the boiler body being disposed upright, e.g. above the combustion chamber the fire tubes being in upright arrangement

Definitions

  • the present invention refers to a return flow boiler having a flue tube connected centrally to one sidewall of a return chamber and is surrounded by a number of fire tubes running backwards therefrom, parallel to the flue tube, which is designed with a specific object to aid the complete combustion of the fuel oil.
  • the invention is characterized by that the outlet of the flue tube into the return chamber is noticeably smaller than the cross section of the main part of the flue tube, in such a manner that the marginal portions of the flame within the flue tube will be forced into the core of the flame, when the latter passes out into the return chamber.
  • the boiler comprises a vertical, cylindrical shell to the upper part of which an oil burner is fitted.
  • the burner is directed into a flue tube 11, which is arranged centrally within the shell, and is connected to one sidewall ofa return chamber 12.
  • a number of fire tubes 13 extend from this chamber backwards, parallel to the flue tube and open into a collecting chamber 14, which is connected to an outlet 15 for the combustion gases.
  • the return chamber 12 has a cup-shaped lower end wall 18 designed as a water chamber, to the perimeter of which a circular row of closely arranged water tubes, preferably provided with fins is arranged the tubes, or fins respectively, being interconnected to form a gastight sidewall in the return chamber, said sidewall being subjected to radiation from a flame entering the chamber.
  • the fire tubes 13 are fitted into two end plates 20, which together with the cylindrical shell 21 enclose a convection part.
  • the water flowing within the latter is guided by baffles 22 arranged in a suitable manner.
  • the water tubes 19 are connected to the lower end plate 20 outside the fire tubes 13. The latter are mounted symmetrically around the flue tube and the temperature will be mainly uniform within this part of the boiler.
  • the flame passes from the flue tube out into the return chamber through an outlet 23, the cross section of which is noticeably smaller than the cross section of the main portion of the flue tube.
  • the marginal portions of the flame which have been in contact with the cooled wall of the flue tube and therefore have a lower temperature than the rest of the flame, are forced into the core of the flame, whereby an efficient combustion of the particles entrained in the marginal portions of the flame is efficiently obtained.
  • the resulting gases are symmetrically distributed in the return chamber and flow through the fire tubes towards the outlet 15.
  • the outlet 23 of the flue tube is cylindrical over a short distance.
  • the portion between the cylindrical main part of the flue tube and the outlet portion is basically a truncated cone having its apex 26 located just outside the outlet, the wall of the transient portion is slightly curved to ensure a smooth flow.
  • a number of guide vanes 27 may be fitted in the cylindrical portions to impart a swirling motion to the flame entering the return chamber, whereby particles of ash and other contaminations are separated by centrifugal action. Such articles are collected at the bottom of the return cham er and may be removed through a cleaning opening 24.
  • the boiler may be arranged with its longitudinal axis horizontal and by the fitting of a steam drum the boiler may be used as a common steam boiler.
  • a return flow boiler having a flue tube connected centrally to one sidewall of a return chamber and being surrounded by a number of fire tubes running backwards therefrom and parallel to the flue tube, a fuel burner being fitted at the end of the flue tube remote from the return chamber and being arranged to direct flame axially into said fire tube, in which the main part of the flue tube is cylindrical and presents a smooth, water-cooled, wall towards the flame, and the outlet of the flue tube is cylindrical over a short distance and noticeably smaller than the cross section of the main part of the flue tube, the transient part between said cylindrical portions being shaped as a truncated cone having its apex just outside the outlet from the flue tube and likewise presenting a smooth, water-cooled wall towards the flame, whereby the marginal portions of the flame within the flue tube will be forced into the core of the flame, when the latter passes out into the return chamber.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Incineration Of Waste (AREA)
  • Sink And Installation For Waste Water (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Combustion Of Fluid Fuel (AREA)
  • Temperature-Responsive Valves (AREA)

Abstract

In return flow boilers the gases flowing along the wall of the flue tube will be cooled, whereby the combustion in the marginal portions of the flame will be considerably less complete than in the core thereof, which will have undesirable consequences when the flame emerges into the return chamber. In order to bring about a complete combustion also of the marginal portions of the flame the outlet of the flue tube is considerably restricted as compared to the main part of the tube, whereby the portions of the flame having flown along the wall of the flue tube will be forced into the core of the flame, when this emerges into the return chamber.

Description

Feb. 1, 1972 United States Patent ()stbo 2,383,924 8/1945 Wayeta1...............................122/182 [54] RETURN FLOW BOILER 1,755,949 4/1930 Clarks0n.... 2,568,781 9/1951 Watts....................................122/182 Inventor: Nils Axel Ambjorn Ostbo, Goteborg,
Sweden Primary Examiner-Kenneth W. Sprague Pierce, Schefiler & Parker ow mm b m mo G \h mm ML W 2.. M m w mm hm HE mt a oe GH [73] Assignee:
Attorney Sweden [57] ABSTRACT In return flow boilers the gases flowing along the wall of the flue tube will be cooled, whereby the combustion in the mar- [22] Filed: Apr. 6, 1970 ginal portions of the flame will be considerably less complete than in the core thereof, which will have undesirable consequences when the flame emerges into the return chamber. In order to bring about a complete combustion also of the marginal portions of the flame the outlet of the flue tube is considerably restricted as compared to the main part of the tube, whereby the portions of the flame having flown along the wall of the flue tube will be forced into the core of the flame, when this emerges into the return chamber.
1 Claims, 1 Drawing Figure References Cited UNITED STATES PATENTS 1,936,623 Frentzel, .lr. 122/ l 82 t) m t) m .I I I I h n f\ 1 m N 5 I RETURN FLOW BOILER BACKGROUND OF THE INVENTION lt is difiicult to bring about a complete combustion of fuel oil in a boiler furnace. This incomplete combustion causes contamination of the heat exchanger surfaces in the boiler and also sanitary inconveniences due to partly burnt particles following the gases into the atmosphere.
SUMMARY OF THE INVENTION The present invention refers to a return flow boiler having a flue tube connected centrally to one sidewall of a return chamber and is surrounded by a number of fire tubes running backwards therefrom, parallel to the flue tube, which is designed with a specific object to aid the complete combustion of the fuel oil. The invention is characterized by that the outlet of the flue tube into the return chamber is noticeably smaller than the cross section of the main part of the flue tube, in such a manner that the marginal portions of the flame within the flue tube will be forced into the core of the flame, when the latter passes out into the return chamber.
BRIEF DESCRIPTION OF THE DRAWING One embodiment of the invention is shown on the accompanying drawing, which is a section through a vertical hot water boiler.
DESCRIPTION OF THE PREFERRED EMBODIMENT The boiler comprises a vertical, cylindrical shell to the upper part of which an oil burner is fitted. The burner is directed into a flue tube 11, which is arranged centrally within the shell, and is connected to one sidewall ofa return chamber 12. A number of fire tubes 13 extend from this chamber backwards, parallel to the flue tube and open into a collecting chamber 14, which is connected to an outlet 15 for the combustion gases. The water enters at 16 and leaves the boiler at 17v The return chamber 12 has a cup-shaped lower end wall 18 designed as a water chamber, to the perimeter of which a circular row of closely arranged water tubes, preferably provided with fins is arranged the tubes, or fins respectively, being interconnected to form a gastight sidewall in the return chamber, said sidewall being subjected to radiation from a flame entering the chamber.
The fire tubes 13 are fitted into two end plates 20, which together with the cylindrical shell 21 enclose a convection part. The water flowing within the latter is guided by baffles 22 arranged in a suitable manner. The water tubes 19 are connected to the lower end plate 20 outside the fire tubes 13. The latter are mounted symmetrically around the flue tube and the temperature will be mainly uniform within this part of the boiler.
The flame passes from the flue tube out into the return chamber through an outlet 23, the cross section of which is noticeably smaller than the cross section of the main portion of the flue tube. In this manner the marginal portions of the flame, which have been in contact with the cooled wall of the flue tube and therefore have a lower temperature than the rest of the flame, are forced into the core of the flame, whereby an efficient combustion of the particles entrained in the marginal portions of the flame is efficiently obtained. The resulting gases are symmetrically distributed in the return chamber and flow through the fire tubes towards the outlet 15. The outlet 23 of the flue tube is cylindrical over a short distance. The portion between the cylindrical main part of the flue tube and the outlet portion is basically a truncated cone having its apex 26 located just outside the outlet, the wall of the transient portion is slightly curved to ensure a smooth flow. A number of guide vanes 27 may be fitted in the cylindrical portions to impart a swirling motion to the flame entering the return chamber, whereby particles of ash and other contaminations are separated by centrifugal action. Such articles are collected at the bottom of the return cham er and may be removed through a cleaning opening 24.
If circulation pumps are used the flow of water within the boiler may be reversed. The boiler may be arranged with its longitudinal axis horizontal and by the fitting of a steam drum the boiler may be used as a common steam boiler.
What I claim is:
l. A return flow boiler having a flue tube connected centrally to one sidewall of a return chamber and being surrounded by a number of fire tubes running backwards therefrom and parallel to the flue tube, a fuel burner being fitted at the end of the flue tube remote from the return chamber and being arranged to direct flame axially into said fire tube, in which the main part of the flue tube is cylindrical and presents a smooth, water-cooled, wall towards the flame, and the outlet of the flue tube is cylindrical over a short distance and noticeably smaller than the cross section of the main part of the flue tube, the transient part between said cylindrical portions being shaped as a truncated cone having its apex just outside the outlet from the flue tube and likewise presenting a smooth, water-cooled wall towards the flame, whereby the marginal portions of the flame within the flue tube will be forced into the core of the flame, when the latter passes out into the return chamber.

Claims (1)

1. A return flow boiler having a flue tube connected centrally to one sidewall of a return chamber and being surrounded by a number of fire tubes running backwards therefrom and parallel to the flue tube, a fuel burner being fitted at the end of the flue tube remote from the return chamber and being arranged to direct flame axially into said fire tube, in which the main part of the flue tube is cylindrical and presents a smooth, water-cooled, wall towards the flame, and the outlet of the flue tube is cylindrical over a short distance and noticeably smaller than the cross section of the main part of the flue tube, the transient part between said cylindrical portions being shaped as a truncated cone having its apex just outside the outlet from the flue tube and likewise presenting a smooth, water-cooled wall towards the flame, whereby the marginal portions of the flame within the flue tube will be forced into the core of the flame, when the latter passes out into the return chamber.
US25622A 1969-04-23 1970-04-06 Return flow boiler Expired - Lifetime US3638622A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE575769 1969-04-23

Publications (1)

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US3638622A true US3638622A (en) 1972-02-01

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US25622A Expired - Lifetime US3638622A (en) 1969-04-23 1970-04-06 Return flow boiler

Country Status (7)

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US (1) US3638622A (en)
CH (1) CH501194A (en)
DE (1) DE2019234A1 (en)
DK (1) DK124704B (en)
FI (1) FI50369C (en)
GB (1) GB1284975A (en)
NO (1) NO127368B (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4157078A (en) * 1976-11-11 1979-06-05 Nils Ostbo Vertical boiler
US4178880A (en) * 1976-11-11 1979-12-18 Nils Ostbo Furnace
US4192260A (en) * 1977-10-27 1980-03-11 Nils Ostbo Air preheating means at a vertical steam or hot water boiler
US4380215A (en) * 1981-07-16 1983-04-19 Mendelson Walton L Liquid fuel-fired water heating tank
US4899696A (en) * 1985-09-12 1990-02-13 Gas Research Institute Commercial storage water heater process
US20070051359A1 (en) * 2005-09-08 2007-03-08 Ozzie Missoum Looped system fuel-fired fluid heating/storage device
CN112963821A (en) * 2021-03-01 2021-06-15 河南农业职业学院 Boiler using high-viscosity fuel oil and waste heat recovery device thereof

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2653862B1 (en) * 1989-10-31 1994-09-02 Seccacier Etu Const Chaudieres BOILER FOR HEATING AND / OR PREPARING DOMESTIC HOT WATER.
IT1271205B (en) * 1994-07-04 1997-05-27 Belleli Spa THREE-WAY SMOKE HEAT GENERATOR

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1755949A (en) * 1927-05-30 1930-04-22 Clarkson Thomas Steam generator and water heater
US1936623A (en) * 1932-06-29 1933-11-28 Milwaukee Air Power Pump Co Apparatus for heating
US2383924A (en) * 1944-11-04 1945-08-28 Milton T Way Heater
US2568781A (en) * 1948-03-11 1951-09-25 Anna May Watts Sergent Vertical boiler

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1755949A (en) * 1927-05-30 1930-04-22 Clarkson Thomas Steam generator and water heater
US1936623A (en) * 1932-06-29 1933-11-28 Milwaukee Air Power Pump Co Apparatus for heating
US2383924A (en) * 1944-11-04 1945-08-28 Milton T Way Heater
US2568781A (en) * 1948-03-11 1951-09-25 Anna May Watts Sergent Vertical boiler

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4157078A (en) * 1976-11-11 1979-06-05 Nils Ostbo Vertical boiler
US4178880A (en) * 1976-11-11 1979-12-18 Nils Ostbo Furnace
US4192260A (en) * 1977-10-27 1980-03-11 Nils Ostbo Air preheating means at a vertical steam or hot water boiler
US4380215A (en) * 1981-07-16 1983-04-19 Mendelson Walton L Liquid fuel-fired water heating tank
US4899696A (en) * 1985-09-12 1990-02-13 Gas Research Institute Commercial storage water heater process
US20070051359A1 (en) * 2005-09-08 2007-03-08 Ozzie Missoum Looped system fuel-fired fluid heating/storage device
CN112963821A (en) * 2021-03-01 2021-06-15 河南农业职业学院 Boiler using high-viscosity fuel oil and waste heat recovery device thereof

Also Published As

Publication number Publication date
CH501194A (en) 1970-12-31
DE2019234A1 (en) 1970-11-12
FI50369C (en) 1976-02-10
NO127368B (en) 1973-06-12
FI50369B (en) 1975-10-31
GB1284975A (en) 1972-08-09
DK124704B (en) 1972-11-13

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