US3375981A - Apparatus for cleaning and inhibiting corrosion in air preheaters and the like - Google Patents

Apparatus for cleaning and inhibiting corrosion in air preheaters and the like Download PDF

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Publication number
US3375981A
US3375981A US508803A US50880365A US3375981A US 3375981 A US3375981 A US 3375981A US 508803 A US508803 A US 508803A US 50880365 A US50880365 A US 50880365A US 3375981 A US3375981 A US 3375981A
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United States
Prior art keywords
discharge
slot
rotor
cleaning
preheater
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Expired - Lifetime
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US508803A
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English (en)
Inventor
Julian W Keck
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Babcock and Wilcox Co
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Individual
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Publication date
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Priority to US508803A priority Critical patent/US3375981A/en
Priority to GB42417/66A priority patent/GB1150749A/en
Priority to SE13933/66A priority patent/SE319261B/xx
Application granted granted Critical
Publication of US3375981A publication Critical patent/US3375981A/en
Assigned to BABCOCK & WILCOX COMPANY THE, A CORP. OF NJ. reassignment BABCOCK & WILCOX COMPANY THE, A CORP. OF NJ. MERGER (SEE DOCUMENT FOR DETAILS). EFFECTIVE DATE:03/31/78 A CORP. OF NJ. Assignors: DIAMOND POWER SPECIALTY CORPORATION
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Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F9/026—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits
    • 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
    • F28G9/00—Cleaning by flushing or washing, e.g. with chemical solvents

Definitions

  • a pair of perforated screens bridge the slot and are arched inwardly into the body in spaced relationship to each other.
  • the perforations in the screens turn the longitudinally flowing liquid 90 and direct it downwardly through the slot, so that the downward flow through the slot is virtually unaffected by horizontal forces resulting from the velocity head in the body.
  • the gates are protected by anchoring angle irons which project from the body in parallel relation to and farther than the gates.
  • the present invention relates to apparatus for cleaning and inhibiting corrosion in heat exchanging devices such as regenerative air preheaters of the rotary type which are used in large steam boilers to recover waste heat from the flue gases.
  • the object of the present invention is to provide an improved treatment device of the indicated character which is so designed and constructed as to provide an improved narrow, sheet-like jet configuration.
  • a further object is to provide an improved elongated discharge head positioned radially in and discharging downwardly ice through the rotor of such a preheater and which delivers a graduated rate of flow from one end to the other of the head, but which does not involve the use of small jets or separate orifices and which employs relatively low pressures in such an accurate and narrowly concentrated sheet-like discharge as to provide improved cleaning and treatment with a reduced quantity of solution and with much less wear and deterioration of the discharge head.
  • Another object is to provide improved apparatus of the indicated character having solution discharge portions which are accurately adjustable throughout their length and from which the discharge rate may preset so as to vary in a desired manner per unit of linear extent of the discharge element.
  • Another object is to provide such apparatus which is of rugged and simple construction, which does not incorporate moving parts, which is not subject to clogging and which is readily serviceable in event any adjustment or replacement is necessary after installation without removing the preheater or boiler from service.
  • FIGURE 1 is a perspective view of an upper portion of the interior of a Ljungstrom-type air preheater equipped with my invention
  • FIGURE 2 is a cross sectional View of the discharge element
  • FIGURE 3 is a longitudinal sectional view of the same, centrally broken away.
  • reference character 10 designates the rotor of a Ljungstrorn-type preheater. As shown in FIGURE 1 the upper portion of the rotor is exposed within the enclosure of the preheater, a portion of the supporting framework 12 being illustrated. As is well known, the rotor turns slowly upon a vertical axis to carry all the heat exchanging parts of the rotor alternately from one to another of two isolated chambers, one chamber forming a section of the flue gas duct discharging into the stack and the other chamber forming a section of the air for combustion discharging into the furnace, so that the portion heated in the stack discharges its heat into the air entering through the air entry duct.
  • the heat transferring portions consist of closely spaced vertical fins which interpose a minimum resistance to vertical flow of the air and flue gases.
  • I provide an elongated discharge head or element, generally designated 16, of rectangular cross section as best shown in FIGURE 2 and which, as best shown in FIGURE 1, is installed in a radial position in either the flue gas chamber or in the air duct chamber of the preheater.
  • the discharge element is of a length to extend across the full effective radial dimension of the rotor and may be attached as by hangers 14 to a suitable stationary radial supporting beam 15 so that its discharge jet portion extends horizontally above the rotor.
  • the discharge portion of the element is positioned from eighteen to twenty-eight inches above the rotor and discharges directly downwardly so that as the rotor turns all portions of the rotor are carried under the sheet-like discharge.
  • the element is located in the down flow section, as indicated, so that the gas flow does not oppose the flow of the cleaning solution, and the element is also angularly spaced from the position at which the rotor leaves the section, so that draining of the rotor may be completed before the rotor moves into the other section of the preheater.
  • the discharge element 16 has an internal transverse width. of 6 /4 inches.
  • I preferably employ a water pressure within the element which is of the order of p.s.i., but pressures as low as 3.5 p.s.i. have been successfully used. It has been found that a high velocity discharge from the element is not necessary for efficient washing of air preheaters of this nature. An important consideration, however, is the concentration of a large volume of liquid in the passages being washed, without permitting a low volume to enter any passages.
  • the bottom of the element is formed by two horizontally inturned flanges having aligned straight edges between which is a central longitudinal slot-like outlet opening 18 approximately one inch wide.
  • a pair of longitudinal orifice contour plates or gates, 20, 21, are provided, one attached to each of the bottom flanges of the element and which coact to define the slot-like discharge opening 50. Discharge slot 50 is unobstructed from end to end.
  • Each of the gates 20, 21 includes a horizontal top flange portion 22, a flat downturned inclined portion 24 sloping inwardly toward the vertical center plane of the assembly, and a flat vertical bottom portion 25 parallel to and spaced from the center plane. Portions 25 which cooperate to define the orifice slot 50 are adjustable toward and from one another.
  • Screw threaded studs 28 are attached to and extend outwardly from the bottom portions of gates 20, 21 at spaced intervals therealong (four-inch spacing is employed in my preferred construction). Studs 28 extend outwardly through holes 30 in elongated angle brace members 32, 33. Each angle 'brace member consists of a flat horizontal top portion as 34 and a vertical portion 35 which extends downwardly slightly formed by gates 20 and 21 so as to protect the members 20 and 21 from damage when installing or removing the element from the air preheater. The contour plates and angle brace members are secured by a plurality of machine screws as 38 to the bottom flanges of the element 16.
  • the holes in the members 20, 21, 32, 33 through which the fastening screws 38 extend are larger than the shanks of the screws, so that the contour plates and their brace members can be set out of parallel, preferably with a graduatedly increasing spacing toward the periphery of the rotor.
  • the contour elements 20, 21 are of thinner gauge material than the angle braces 32, 33 and less stifl, so that the flanges 24 of elements 20, 21 are flexible laterally to enable very accurate adjustment of the spacing between them.
  • Such adjustment by flexure of the gates is effected by means of jam nuts 40, 42 on the studs 28 and engageable with opposite sides of the vertical flanges 35 of the angle brace members.
  • the gates can 'be flexed to adjust the width of the slot 5t), and vice versa.
  • the linear velocity of the rotor, and the amount of material to be cleaned passing under the element per unit time, are greater toward the periphery, and the slot 50 is accordingly so adjusted as to be proportionately narrower toward the center of the preheater rotor, as indicated, and the rate of solution discharge is therefore graduated, throughout the length of the element, from a maximum near the periphery to a minimum at the center.
  • the volume of wash liquid required per square foot of heat exchanging area is greater near the center than near the periphery of such a cylindrical drum type preheater rotor, however, so that although the slot gates may be adjusted for a lesser flow rate toward the center, as indicated, the actual ratio of flow rate to area is usually desirably substantially greater toward the center.
  • a pressure equalizing screen 52 is provided re-entrantly arched upwardly into the interior of the element 16 and overlying and enclosing an area above the slot 18 to provide an elongated chamber 54 extending lengthwise above the slot 18 through which the water solution must flow.
  • a second arched screen 55 may also be incorporated spacedly below screen 52, thereby defining a second elongated chamber 58 through which the material must pass before reaching the discharge slot 50.
  • the for-aminous screen members 52, 55 are formed of sheet metal perforated with holes on /8" centers, and overlie and are spaced inwardly from the slot-like discharge opening throughout the length of the assembly, and are blocked at their ends, as shown in FIGURE 3, as by end plates 57, 58, so that the liquid must pass successively through the screens 52-55 in order to reach the outlet.
  • the screens are provided at their lower edges with outturned flanges clamped between the bottom flanges of element 16 and a perforated plate 60 which bridges the slot-like opening 18 to rigidly tie and position the bottom flanges of the element.
  • Plate 60 is provided with large closely-spaced openings 62 through which the olution flows to the outlet slot 50.
  • Flat gaskets as 64, 65 may be interposed between plate 60 and the gates 20, 21 and body 16, as shown in FIG- URE 2.
  • the solution inlet pipe 65 is connected to the outer end of the element so that the liquid enters the element longitudinally and entirely above the screens 52, 55 which are thus interposed between the inlet and the outlet slot.
  • a preheater rotor having a radial dimension of approximately ten feet
  • the discharge slot in the element 16 being of course of the same length
  • a successful washing operation has been obtained with the slot so adjusted as to obtain a flow rate of approximately 30 gallons per minute near the center of the rotor, which is equivalent to approximately 25 gallons per square foot of area washed, and a flow rate of 96.7 g.p.m. near the periphery of the rotor, which is equivalent to approximately 20 gallons per square foot.
  • the slot width tapers uniformly from .214 inch at the outer, peripheral end to .070 inch at the inner end, and total consumption is approximately 650 g.p.m.
  • the arched screens 52 and 55 direct the wash liquid approaching the slot-like discharge opening of the element downwardly and substantially eliminate the effects of the horizontal forces resulting from the velocity head of the liquid in the element, thereby achieving a flow which is a substantially true function of the static head and attaining a sharply defined sheet-like pattern. It has been found that when two arched screens of the indicated character are employed, flow rate can be increased or decreased as much as 50% and the pressure of the liquid supply can be varied widely, with no measurable change in the proportion of flow volume throughout the length of the discharge slot. It is thus possible to introduce the washing solution directly into the interior of the element at one end without distortion of the pattern of the discharge due to the velocity head.
  • An elongated hollow distributor element arranged to discharge liquid laterally therefrom along its length and comprising a tubular body having an inlet at one end and a slot-like discharge opening extending along one side, means in the body for controlling the flow through said opening comprising a foraminous member overlying and bridging said opening throughout the length of the opening, and arched inwardly within the distributor ele ment from the opening and a second forarninous member arched inwardly from the opening to a substantially greater extent, said members forming serially disposed screens bridging and extending longitudinally of said opening and interposed between said inlet and the discharge opening.
  • An elongated hollow distributor element arranged to discharge liquid laterally therefrom along its length and comprising a tubular body having an inlet at one end and a slot-like discharge opening extending along one side, means in the body for controlling the flow through said opening comprising a foraminous member overlying and bridging said opening throughout the length of the opening, elongated angle members defining a pair of discharge gates extending longitudinally of and laterally from and sealed with respect to the body on opposite sides of said opening, and releasable positioning means for individually attaching said members to the body, said positioning means including portions located relatively close to the gates and projecting laterally farther than the gates to protect the latter against unwanted mechanical distortion.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
US508803A 1965-11-19 1965-11-19 Apparatus for cleaning and inhibiting corrosion in air preheaters and the like Expired - Lifetime US3375981A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US508803A US3375981A (en) 1965-11-19 1965-11-19 Apparatus for cleaning and inhibiting corrosion in air preheaters and the like
GB42417/66A GB1150749A (en) 1965-11-19 1966-09-22 Liquid Distributors for Cleaning and Inhibiting Corrosion in Air Preheaters and the Like
SE13933/66A SE319261B (enrdf_load_html_response) 1965-11-19 1966-10-13

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US508803A US3375981A (en) 1965-11-19 1965-11-19 Apparatus for cleaning and inhibiting corrosion in air preheaters and the like

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US3375981A true US3375981A (en) 1968-04-02

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GB (1) GB1150749A (enrdf_load_html_response)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4270702A (en) * 1978-04-26 1981-06-02 Albany International Corp. Adjustable orifice air knife
US4565325A (en) * 1982-04-23 1986-01-21 Mannesmann Aktiengesellschaft Water cooling apparatus for metal sheets and belts
US6666038B1 (en) 2002-09-13 2003-12-23 Richard A. Hynes Air conditioning system including liquid washdown dispenser and related methods

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US647283A (en) * 1899-11-11 1900-04-10 Francois Joseph Singruen Regulable ajutage for hydraulic motors.
US888693A (en) * 1907-09-09 1908-05-26 Valentin Aranguren Y Bustinza Paint-machine.
US962209A (en) * 1909-07-24 1910-06-21 William H Gailor Road-oiler.
US1248565A (en) * 1916-08-26 1917-12-04 James B Slattery Gas-burner.
US2029337A (en) * 1932-11-21 1936-02-04 California Spray Chemical Corp Nozzle
DE678901C (de) * 1937-06-06 1939-07-24 Danneberg & Quandt Gasschlitzbrenner
DE679687C (de) * 1937-03-03 1939-08-14 I G Farbenindustrie Akt Ges Schlitzbrenner, insbesondere fuer die Oberflaechenhaertung
CA504958A (en) * 1954-08-10 Canadian International Paper Company Shower for pulp washers
US2779478A (en) * 1954-05-04 1957-01-29 Spraying Systems Co Tapered strainer and assemblies
US3002700A (en) * 1958-07-26 1961-10-03 Mohring Gustav Nozzle on heat-treatment machines for textile fabrics and the like
DE1146612B (de) * 1958-12-30 1963-04-04 Otto Hebenstreit Dr Ing OElgasbrenner-Rohr, insbesondere fuer Backoefen
US3085754A (en) * 1960-10-04 1963-04-16 Walter Van E Thompson Half-circle sprinkler head

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA504958A (en) * 1954-08-10 Canadian International Paper Company Shower for pulp washers
US647283A (en) * 1899-11-11 1900-04-10 Francois Joseph Singruen Regulable ajutage for hydraulic motors.
US888693A (en) * 1907-09-09 1908-05-26 Valentin Aranguren Y Bustinza Paint-machine.
US962209A (en) * 1909-07-24 1910-06-21 William H Gailor Road-oiler.
US1248565A (en) * 1916-08-26 1917-12-04 James B Slattery Gas-burner.
US2029337A (en) * 1932-11-21 1936-02-04 California Spray Chemical Corp Nozzle
DE679687C (de) * 1937-03-03 1939-08-14 I G Farbenindustrie Akt Ges Schlitzbrenner, insbesondere fuer die Oberflaechenhaertung
DE678901C (de) * 1937-06-06 1939-07-24 Danneberg & Quandt Gasschlitzbrenner
US2779478A (en) * 1954-05-04 1957-01-29 Spraying Systems Co Tapered strainer and assemblies
US3002700A (en) * 1958-07-26 1961-10-03 Mohring Gustav Nozzle on heat-treatment machines for textile fabrics and the like
DE1146612B (de) * 1958-12-30 1963-04-04 Otto Hebenstreit Dr Ing OElgasbrenner-Rohr, insbesondere fuer Backoefen
US3085754A (en) * 1960-10-04 1963-04-16 Walter Van E Thompson Half-circle sprinkler head

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4270702A (en) * 1978-04-26 1981-06-02 Albany International Corp. Adjustable orifice air knife
US4565325A (en) * 1982-04-23 1986-01-21 Mannesmann Aktiengesellschaft Water cooling apparatus for metal sheets and belts
US6666038B1 (en) 2002-09-13 2003-12-23 Richard A. Hynes Air conditioning system including liquid washdown dispenser and related methods

Also Published As

Publication number Publication date
GB1150749A (en) 1969-04-30
SE319261B (enrdf_load_html_response) 1970-01-12

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Legal Events

Date Code Title Description
AS Assignment

Owner name: BABCOCK & WILCOX COMPANY THE, A CORP. OF NJ.

Free format text: MERGER;ASSIGNOR:DIAMOND POWER SPECIALTY CORPORATION;REEL/FRAME:003854/0861

Effective date: 19780331

Owner name: BABCOCK & WILCOX COMPANY THE, A CORP. OF NJ., NEW

Free format text: MERGER;ASSIGNOR:DIAMOND POWER SPECIALTY CORPORATION;REEL/FRAME:003854/0861

Effective date: 19780331