EP0014719A1 - Procede de nettoyage sonique - Google Patents

Procede de nettoyage sonique

Info

Publication number
EP0014719A1
EP0014719A1 EP79900482A EP79900482A EP0014719A1 EP 0014719 A1 EP0014719 A1 EP 0014719A1 EP 79900482 A EP79900482 A EP 79900482A EP 79900482 A EP79900482 A EP 79900482A EP 0014719 A1 EP0014719 A1 EP 0014719A1
Authority
EP
European Patent Office
Prior art keywords
pressure
space
wave
pressure wave
membranes
Prior art date
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.)
Withdrawn
Application number
EP79900482A
Other languages
German (de)
English (en)
Inventor
Bengt Lennart Holm
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kockums Automation AB
Original Assignee
Kockums Automation AB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kockums Automation AB filed Critical Kockums Automation AB
Publication of EP0014719A1 publication Critical patent/EP0014719A1/fr
Withdrawn legal-status Critical Current

Links

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
    • F28G7/00—Cleaning by vibration or pressure waves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
    • B08B7/02—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by distortion, beating, or vibration of the surface to be cleaned
    • B08B7/026—Using sound waves

Definitions

  • vibration energy is supplied usually as pressure waves from a high-power sound emitter which is mounted in a wall with some external air cooling, and is distributed to different parts of the space, e.g. the narrow spaces between a plurality of boiler tubes in a boiler installation.
  • a high sound pressure level is required in order to obtain a satisfactory cleaning.
  • problems may be involved in distributing the vibration energy to all parts of the space which is often of complicated form, considering the occurence of sound shadow although there is obtained in most cases a surprisingly uniform distribution of the pressure waves due to reflection of the sound in the space to be cleaned.
  • the range can be extended by increasing the acoustic power generated by the sound emitter in order to increase the sound pressure level but in this respect there are technical limitations because the construction of the sound emitter will be ve ry complicated and expensive if a substantial increase of the power is required. Moreover, the production of acoustic power generally is relatively expensive.
  • a better alternative of increasing the acoustic range could be to concentrate the pressure wave emitted by the sound emitter to different portions of the space to be cleaned but no practicable method has been available so far in order to achieve by simple means such a concentration of the sound from a sound transmitter of the type commonly used in sonic cleaning.
  • the object of the invention is to provide by simple means a concentration of the pressure wave to different portions of the space to be cleaned also when these portions are located at a great distance from the. pressure wave generator, and more particularly by using conventional pressure wave generators operating in the frequency and power ranges now commonly applied in sonic cleaning.
  • the invention provides a method in sonic cleaning of a space wherein there is a tendency of a coating being formed on the surfaces thereof, characterized in that pressure waves are emitted from at least two mutually spaced locations in the space, and in that an amplified pressure wave is produced by controlled phase shift of the pressure wave emitted from one location in relation to the pressure wave emitted from the other location, said amplified pressure wave scanning the space.
  • FIG. 1 diagrammatically illustrates how the wave from two synchronous sound emitters can be induced to change the direction thereof by a relative phase shift of the pressure waves emitted from the two sound emitters;
  • FIG. 2 discloses an arrangement of two pneumatically operated sound emitters for providing said phase shift.
  • FIG. 1 there are shown therein two sound emitters A and B spaced a distance a ⁇ from each other.
  • the sound emitters in this case are parallel to each other but this is not necessary; the directions of the sound emitters also can converge or diverge. It is also possible to arrange the sound emitters opposite to each other. If it is assumed that the two sound emitters generate sound waves comprising a single frequency component only, having the wave length ⁇ , and if it is also assumed that these frequency components are fully synchronized and without phase shift, the wave front will propagate in the direction A/B - Al/Bl.
  • a scanning pressure wave i.e. a pressure wave moving forwards and backwards, which can be utilized in order to cover the several portions of a space of a furnace, heat exchanger or similar apparatus at maximum power or intensity also when the space has large dimensions and/or complicated form.
  • the two sound emitters can be located in a wall of this space or in adjacent or opposite walls at a place where they can be mounted easily.
  • the total sound pressure amplitude will be twice as large, which means that the power, or intensity of the pressure wave will be increased by about 6 db. It is assumed that the amplitudes of the two sound emitters are equal. In an addition other than the in-phase addition, e.g. of two frequencies which are not adjacent to each other, there is obtained an increase of the power or intensity of about 3 db only.
  • FIG. 2 discloses a practical embodiment of an apparatus for working the method according to the invention for sonic cleaning of a space as described with reference to FIG. 1.
  • the two sound emitters are of the pneumatic type and comprise a membrane housing 10A and 10B, respectively, and an acoustic horn 11A and 11B, respectively.
  • the emitters are mounted in a wall 12 of the space 13 to be cleaned, and pressurized air at the pressure P ⁇ is supplied through a conduit 14.
  • Synchronism of the two pneumatically operated sound transmitters A and B can be obtained by spacing these sound emitters such a distance a that they interact by so-called external coupling via the acoustic horns 11A and 11B.
  • the relative phase shift can be mastered only if the chambers behind the membranes in the membrane housings 10A and 10B are interconnected by means of an acoustic wave guide, and in FIG. 2 this connection is provided by a conduit 15 so that a stable phase position will appear at a definite length of this conduit.
  • This method of combining an external acoustic coupling and a coupling which is bound to a conduit provides the possibility to control the phase shift from e.g. T. radianes (synchronization in opposition) to a value sliding cyclically from ⁇ to 0 (in-phase synchronization). Sliding of this type can take place if the length of the conduit 15 is somewhat shorter or longer than the optimum length for a stable phase position.
  • the sliding can be controlled in a desired manner if there is maintained behind the membranes during operation of the sound emitters a pressure P. which is lower than the pressure P existing at the supply side of the membranes.
  • pressurized air can be supplied to the conduit 15 and the pressure in this conduit and the chambers behind the membranes can be adjusted to a desired value P b by means of a regulator 16.
  • a desired pressure in the conduit 15 and the chambers behind the membranes in the membrane housings 10A and 10B can also be obtained by arranging a connection for pressurized air in one or both of the sound emitters between the supply side of the membrane and the chamber at the rear side of the membrane, e.g. by providing an opening in the membrane, so that pressurized air is supplied from the supply side of the sound emitters, the pressure in the conduit 15 and the chambers behind the membranes being adjusted by con trolled discharge of air through the pressure regul or 16.
  • the pressure wave propagates as several separate lobes.
  • Scanning comprising a continuously repeated movement from one side to the other of the amplified pressure wave can be obtained also in another manner, viz. if the frequencies of the sound emitters differ from each other to a minor extent, e.g. by 1 Hz, so that there is obtained a beat frequency of the pressure waves. Then, the phase shift will continuously vary between negative and positive values and the waves will be in-phase, i.e. there will be no phase shift, for a short moment only of each beat cycle. It should be noted that the significant increase of the power and intensity of the pressure wave by in-phase addition will have time to affect the dust coating in the space 13 also at these relatively short but repeated instances when the amplified scanning pressure wave passes a location in the space.
  • the sound emitters can also consist of sound emitters of other types such as electric sound emitters.
  • the phase shift or phase change in order to obtain the periodical scanning of the amplified pressure wave can be obtained electronically by applying methods known in the art.
  • pressure wave generators it is possible to use sound emitters for audible sound in the approximate frequency range 20 - 20,000 Hz as well as devices e.g. pulsators for non-audible sound, infrasound, in the approximate frequency range 2 - 20 Hz. Excellent practical results have been obtained at frequencies in the range extending from 60 to 800 Hz.
  • the cleaning may be performed either while the gas with dust entrained therein passes through the space to be cleaned or during a period when the gas flow is interrupted. This latter procedure provides the advantage that the loosened dust cannot be withdrawn with the gas.
  • the method of sonic cleaning according to the invention can be applied not only in furnaces, heat exchangers or similar apparatuses through which gas is flowing at least intermittently, but also in cold stores wherein ice deposits on cooling coils and cooling-coil batteries and also on the walls cause problems by reducing the efficiency of the cooling installation.
  • a further field wherein the method according to the invention can be applied is in spray dryers wherein the powder produced by condensing a liquid can have a tendency of adhering to the walls and the devices in the spray drying compartment.
  • an antistate agent can be supplied to the space 13 together with the drive fluid (pressurized air) in order to prevent the loosened dust from being attracted to the cleaned surfaces again due to electrostatic forces.

Abstract

Procede de nettoyage sonique d'un espace (13) ou une couche a tendance a se former sur ses surfaces. Par dephasage relatif commande d'ondes de pression emises a partir de deux points d'emission espaces l'un par rapport a l'autre (A, B), on produit une onde de pression amplifiee qui balaye l'espace, ladite onde de pression detachant la couche en agissant sur les surfaces de l'espace (13).
EP79900482A 1978-05-02 1979-12-04 Procede de nettoyage sonique Withdrawn EP0014719A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE7805006 1978-05-02
SE7805006A SE7805006L (sv) 1978-05-02 1978-05-02 Sett vid sonikrensning

Publications (1)

Publication Number Publication Date
EP0014719A1 true EP0014719A1 (fr) 1980-09-03

Family

ID=20334807

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79900482A Withdrawn EP0014719A1 (fr) 1978-05-02 1979-12-04 Procede de nettoyage sonique

Country Status (4)

Country Link
EP (1) EP0014719A1 (fr)
JP (1) JPS55500355A (fr)
SE (1) SE7805006L (fr)
WO (1) WO1979001019A1 (fr)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4461651A (en) * 1983-02-08 1984-07-24 Foster Wheeler Limited Sonic cleaning device and method
US4655846A (en) * 1983-04-19 1987-04-07 Anco Engineers, Inc. Method of pressure pulse cleaning a tube bundle heat exchanger
US4645542A (en) * 1984-04-26 1987-02-24 Anco Engineers, Inc. Method of pressure pulse cleaning the interior of heat exchanger tubes located within a pressure vessel such as a tube bundle heat exchanger, boiler, condenser or the like
SE451115B (sv) * 1985-01-16 1987-09-07 Ulveco Kockum Sonic Ab Anleggning for sotning av pannor eller liknande, innefattande ett flertal lagfrekvent ljud alstrande anordningar
US4773357A (en) * 1986-08-29 1988-09-27 Anco Engineers, Inc. Water cannon apparatus and method for cleaning a tube bundle heat exchanger, boiler, condenser, or the like
SE457822B (sv) * 1986-11-28 1989-01-30 Svenska Rotor Maskiner Ab Foerfarande foer aastadkommande av selektivt styrda tryckpulser i en gasmassa samt anordning foer genomfoerande av foerfarandet
JPH02104893U (fr) * 1989-02-01 1990-08-21
US5461123A (en) * 1994-07-14 1995-10-24 Union Carbide Chemicals & Plastics Technology Corporation Gas phase fluidized bed polyolefin polymerization process using sound waves
GB0307250D0 (en) * 2003-03-28 2003-04-30 Boc Group The Inhibiting or removing deposition of particulates
DE102005055813B4 (de) * 2005-11-21 2013-03-21 Fritz Egger Gmbh & Co. Vorrichtung und Verfahren zur Herstellung von Holzwerkstoffen sowie Verfahren zur Abreinigung
WO2015044178A1 (fr) * 2013-09-25 2015-04-02 John Bean Technologies Ab Procédé pour le dégivrage d'un agencement de refroidissement de gaz d'un congélateur
CN105020725B (zh) * 2015-07-08 2016-06-08 南京常荣声学股份有限公司 一种基于复合流的锅炉除灰器
EP3210678A1 (fr) * 2016-02-29 2017-08-30 AV Sootblower AB Nettoyeur acoustique

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3295596A (en) * 1963-12-17 1967-01-03 Standard Oil Co Heat exchanger and cleaning means therefor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO7901019A1 *

Also Published As

Publication number Publication date
WO1979001019A1 (fr) 1979-11-29
JPS55500355A (fr) 1980-06-19
SE7805006L (sv) 1979-11-03

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19811217

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Inventor name: HOLM, BENGT LENNART