Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
  • F28G3/00—Rotary appliances
  • F28G3/16—Rotary appliances using jets of fluid for removing debris
  • F28G3/166—Rotary appliances using jets of fluid for removing debris from external surfaces of heat exchange conduits
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
  • B08B9/08—Cleaning containers, e.g. tanks
  • B08B9/093—Cleaning containers, e.g. tanks by the force of jets or sprays
  • B08B9/0936—Cleaning containers, e.g. tanks by the force of jets or sprays using rotating jets
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J3/00—Removing solid residues from passages or chambers beyond the fire, e.g. from flues by soot blowers
  • F23J3/02—Cleaning furnace tubes; Cleaning flues or chimneys
  • F23J3/023—Cleaning furnace tubes; Cleaning flues or chimneys cleaning the fireside of watertubes in boilers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B13/00—Machines or plants for applying liquids or other fluent materials to surfaces of objects or other work by spraying, not covered by groups B05B1/00 - B05B11/00
  • B05B13/06—Machines or plants for applying liquids or other fluent materials to surfaces of objects or other work by spraying, not covered by groups B05B1/00 - B05B11/00 specially designed for treating the inside of hollow bodies
  • B05B13/0627—Arrangements of nozzles or spray heads specially adapted for treating the inside of hollow bodies
  • B05B13/0636—Arrangements of nozzles or spray heads specially adapted for treating the inside of hollow bodies by means of rotatable spray heads or nozzles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
  • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
  • B05B3/04—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements driven by the liquid or other fluent material discharged, e.g. the liquid actuating a motor before passing to the outlet
  • B05B3/0409—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements driven by the liquid or other fluent material discharged, e.g. the liquid actuating a motor before passing to the outlet with moving, e.g. rotating, outlet elements
  • B05B3/0418—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements driven by the liquid or other fluent material discharged, e.g. the liquid actuating a motor before passing to the outlet with moving, e.g. rotating, outlet elements comprising a liquid driven rotor, e.g. a turbine
  • B05B3/0422—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements driven by the liquid or other fluent material discharged, e.g. the liquid actuating a motor before passing to the outlet with moving, e.g. rotating, outlet elements comprising a liquid driven rotor, e.g. a turbine with rotating outlet elements

Definitions

• the present invention relates to a method and an apparatus for cleaning open boiler flue surfaces in an incineration plant.
• the invention also relates to a cleaning head.
• This object is achieved by a method for cleaning open boiler flue surfaces in an open flue of an incineration plant during operation as explained below.
• the method comprises
• the apparatus is then provided in one embodiment with a cleaning head, wherein the rotational direction of the nozzle head is changeable.
• a suitable gear then changes between the rotational directions.
• the apparatus comprises a single cleaning head with two nozzle heads, for example placed in extension of each other and driven simultaneously in opposite directions by a gear connected to each nozzle head for rotation thereof in opposite directions.
• a replacement of a first cleaning head with a second similar cleaning head is carried out between a first and second cleaning, wherein the first and the second cleaning heads have nozzle heads with opposing rotation.
• the apparatus is designed for cleaning with only a single cleaning head at a time, and wherein the two cleaning heads are designed with a coupling for optional mounting of the one or the second cleaning head on the wire.
• the nozzle head is lowered into the boiler while it is in operation, meaning that the nozzle head is introduced, for example lowered, into an aggressive flue gas environment which fea tures a temperature of 800-1000 degrees Celsius, and wherein the water sprayed on the walls expands 1500-1700 times with a corresponding turbulence in the flue, which results in a significant load on the nozzle head, regardless of whether it is continuous ly cooled by the water flowing through the nozzle head.
• a simple design of the nozzle head is preferable.
• the cleaning head is then, for introduction into the open flue and during cleaning, mounted on a wire, for example a flexible hose in the case of lowering, typically steel- reinforced hose.
• the flexible hose is advantageously a bellows-type metal hose, pref erably of stainless steel. It is typically lowered through an opening found at the top of the open flue to be cleaned, and guided downwards, while cleaning liquid is fed to the nozzles for application on the surfaces to be cleaned, in an efficient manner.
• the flex ible hose structure minimises the amount of space required to introduce the cleaning apparatus into the open flue, allowing the use of the apparatus in connection with ex isting installations substantially without any modifications thereof.
• the cleaning head is introduced with a rigid wire, such as a hollow rod, in a horizontal or inclined direction.
• the cleaning head comprises a turbine chamber and a nozzle head connected rotatably thereto having multiple nozzles, from which the cleaning liquid is sprayed against the boiler flue surfaces during rotation of the nozzle head.
• the turbine chamber contains a turbine driven by the cleaning liquid in its flow from the wire, for example the hose, to the nozzles, wherein a gear exchange between the turbine and the nozzle head drives the nozzle head and reduces the rotational speed of the nozzle head in relation to the turbine.
• a typical rotational speed for the nozzle head is between 1 and 50, preferably between 5 and 10, revolutions per minute.
• the apparatus comprises a mechanism for providing a mainly linear, for example vertical, movement of the nozzle head inside the open flue.
• the mechanism comprises a hose wheel with a drive unit for lowering and raising the cleaning head on the flexible hose, for example on the end of the flexible hose, downwards and upwards within the open flue.
• the drive unit for the hose reel is a speed-controlled gear motor.
• cleaning liquid is fed to the nozzle head from a feed water pump, which feeds the cleaning liquid through the wire, for example the flexible hose, at a prede- termined pressure.
• the feed water pump is pressure-controlled to a pres sure level of less than 10 bar for the cleaning liquid.
• the nozzles of the nozzle head are of a type that keep the jet flowing out of the nozzles concentrated with only minor dissolution into droplets.
• the turbine chamber contains a turbine flange with ducts feeding clean- ing liquid from the wire to the turbine.
• the turbine has a rotational axis and turbine blades which have a surface with a normal that extends perpendicularly from the sur face.
• the normal of the turbine blade is angled at an angle w in relation to the rota tional axis of the turbine.
• the ducts are inclined at an angle v in relation to the rotational axis in order to hit the turbine at a steeper approach angle thereto.
• the v:w ratio is in the range of 0.1 to 0.9, preferably between 0.2 and 0.8.
• the angle v is in the interval of 20- 40 degrees.
• the angle v is in the range of 25-35 degrees, such as about 30 degrees
• the normal angle w is in the range of 40-50 degrees, such as about 45 degrees.
• Fig. 1 schematically shows an incineration plant in which the present invention is implemented
• Fig. 2 schematically shows a cleaning head in cross-section, as it is known in the prior art and which in principle can be used for the improved cleaning meth od;
• Fig. 3 schematically shows a hose reel with a drive unit for controlled lowering and raising of the cleaning head, as well as a pump unit for feeding cleaning liq uid to the flexible hose;
• Fig. 4 shows a set of two nozzle heads with opposite rotational directions
• Fig. 5 shows a set of two opposing turbines with a) perspective towards the turbine blade and with b) perspective on top of the turbine flange.
• the incineration plant shown in Fig. 1 comprises three consecutive open flues 17, 18, 19, wherein heat is transferred from flue gases to boiler pipes covering the walls of the open flues 17, 18, 19. After the open flues 17, 18, 19 is located a su- perheater 20 or multiple such superheaters or other boiler structures. In such a plant, it is desired to keep the heat exchanger surfaces clean in the open flues 17, 18, 19 in order to reduce the heat transmission resistance from flue gases to boiler pipes.
• the cleaning apparatus shown in Fig. 1, which is implemented in the incineration plant and is in principle known from EP1291598, comprises a cleaning head 1, as shown in Fig.
• the rotation of the nozzle head 4, as shown in Fig. 2, is provided by means of a tur bine 2 driven by cleaning liquid, for example water, entering the cleaning head 1 from the flexible hose 7 and fed into the turbine 2 in the turbine chamber 22 through ducts 21 in a turbine flange 23, in which the turbine 2 is seated.
• cleaning liquid for example water
• the exchange comprises an external toothed gear 31 located on the turbine shaft, which drives a toothed wheel 32, the axle of which, by means of an ex ternal cogging 33, drives a gear 34 attached to the nozzle head 4.
• Multiple nozzles 5 are mounted on the nozzle head 4 in order to distribute the cleaning liquid in different directions during the rotation of the nozzle head 4.
• the hose reel 6 is suspended for rotation on an axle driven by a drive unit 8 for the hose reel 6, wherein the drive unit 8 comprises an electric motor 9 and a reduction gear mechanism 10.
• the electric motor 9 is controlled from a controller 15 that controls motor speed and the rotational direction of the motor 9.
• the cleaning liquid is fed to the hose 7 by means of a pump unit 11 comprising an electric motor 12 which operates a pump 13.
• the electric mo tor 12 is controlled by the controller 15 in order to be able to control the pressure of the cleaning liquid fed to the flexible hose 7.
• the connection between the pump 13 and the hose reel 6 comprises a rotational coupling 14 to allow the hose reel 6 to rotate in relation to the fixedly located pump 13.
• each of the open flues 17, 18, 19 has a centrally placed opening 16 for the introduction of the cleaning head 1 and the flexible hose 7 and for lowering and raising the cleaning head 1 downwards and upwards in the open flues 17, 18, 19.
• cleaning liquid is fed through the flexible hose 7, thereby rotating the nozzle head 4, and cleaning liquid is applied to the the internal surfaces in the open flues 17, 18, 19 through nozzles 5.
• These nozzles 5 are sized to apply a concentrated j et of cleaning liquid to the internal surfaces of the open flues 17, 18, 19, substantially without the concentrated jets dis solving into drops.
• the cleaning liquid is preferably water, which evaporates when it hits the internal surfaces of the open flues 17, 18, 19, whereby the water expands to a volume approximately 1500-1700 times its original volume, which expansion pro- vides the forces needed to remove dirt from the surfaces hit.
• the cleaning is carried out during operation, i.e. the incineration plant bums fuel and produces heat, and the surfaces to be cleaned have a high temperature which is neces sary to provide evaporation of the cleaning liquid. Due to the fact that cleaning is carried out during operation of the plant, the cleaning may be carried out at any time deemed necessary, e.g.
• a single cleaning system can service multiple open flues 17, 18, 19 by providing suita- ble means for introducing the cleaning head 1 and the flexible hose 7 through the cor responding openings 16.
• deviations comprising, inter alia, provision of multiple openings 16 for each of the open flues 17, 18, 19 to be cleaned, in order to move the cleaning head 1 upwards and downwards closer to the surfaces, wherein the openings 16 are located at a distance from the central part of each open flue 17, 18, 19, provision of automatic means for opening and closing the openings 16, provision of multiple cleaning systems, e.g. a cleaning system for each open flue 17, 18, 19, wherein each such cleaning system comprises its respective cleaning head 1, flexible hose 7 and hose reel 6, etc.
• Fig. 4 shows a set of cleaning heads 1 with turbine chamber 22 and nozzle heads 4 with nozzles 5 oriented to spray in opposite directions.
• turbines 2 are pro vided inside the nozzle heads, which are respectively oriented oppositely, as shown in Fig. 5a.
• the turbine blades 28 have an inclined orientation in relation to the rotational axis 27.
• the normal 29 to the surface of the turbine blades 28 has an angle w in relation to the rotational axis 27 of the turbine 2.
• the normal 29 is the average normal in the area where the cleaning liquid from the duct 21 hits the turbine blade 28.
• the ducts 21 in the turbine flange 23 are inclined at an angle v in relation to the rotational axis 27, as indi cated by the inclined line 25 in Fig. 5b in relation to the dotted line 26 parallel to the rotational axis 27.
• the corresponding line 25' in the second tur bine flange is inclined in the opposite direction and adapted to the second turbine, which has an opposite rotational direction.
• the ducts 21 effect a more targeted force impact on the turbine blades 28, which has been found to be an advantage, in particular in the case of reduced water flow, which reduces water con- sumption without deterioration of the cleaning capacity.
• the v:w ratio is in the range of 0.1 to 0.9, preferably between 0.2 and 0.8.
• the angle v is about 30 degrees
• Fig. 5c shows a line drawing of the turbine flange 23.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Cleaning By Liquid Or Steam (AREA)

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Cited By (1)

Citations (6)

• 2019
  • 2019-10-04 DK DKPA201970621A patent/DK180366B2/da active IP Right Maintenance
• 2020
  • 2020-10-01 WO PCT/DK2020/050265 patent/WO2021063465A1/en active Application Filing

Patent Citations (6)

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