Reciprocating spray cleaning system for air-cooled heat exchangers

Abstract

A frame-mounted mobile cleaning system permanently positionable above or below the tube bundles of an air-cooled heat exchanger (ACHE) and in fluid communication with an external source of pressurized cleaning fluid includes a mobile transverse spray head assembly formed from a plurality of separate interchangeable fluid compartments, each fluid compartment having an inlet for receiving the pressurized cleaning fluid and a fluid discharge wall having at least one nozzle aligned with the longitudinal axes of the finned heat exchange tubes below or above, or elongated slot nozzles that are transverse to the axes of the finned tubes and that are configured to discharge a predetermined pattern of pressurized cleaning fluid onto and between the surfaces of the fins of the heat exchange tubes as the assembly is moved from one end of the ACHE tube bundles to the other.

Claims

1. A cleaning system which is permanently positionable in spaced-apart relation above an uppermost tube bundle or below a lowermost tube bundle of an ACHE and configured for reciprocating movement along longitudinal axes of finned heat exchange tubes forming the uppermost tube bundle or the lowermost tube bundle, the cleaning system comprising: a transversely mounted spray head assembly extending across the longitudinal axes of the finned heat exchange tubes forming the uppermost or lowermost tube bundle, the spray head assembly comprising a plurality of interchangeable fluid compartments that are securely assembled in close-fitting relation with one another to span a width of an opening of the ACHE containing the uppermost or lowermost tube bundle, each interchangeable fluid compartment having an inlet for admitting a pressurized cleaning fluid, the spray head assembly having at least one fluid conduit in fluid communication with the plurality of interchangeable fluid compartments and with an external source of the pressurized cleaning fluid, each of the plurality of interchangeable fluid compartments having a fluid discharge wall proximate the uppermost or lowermost tube bundle, each fluid discharge wall having one or more spray nozzles in fluid communication with the interior of the interchangeable fluid compartment, the one or more spray nozzles generally aligned with the longitudinal axes of the finned heat exchange tubes forming the uppermost or lowermost tube bundle and configured to direct a spray of the pressurized cleaning fluid onto and between the finned heat exchange tubes during movement of the spray head assembly.

2. The cleaning system of claim 1 in which at least one of each of the one or more spray nozzles in the discharge wall are configured to discharge a pressurized spray pattern having a central longitudinal axis aligned with the longitudinal axis of a finned heat exchange tube to which the nozzle is proximate.

3. The cleaning system of claim 1 in which each of the plurality of interchangeable fluid compartments comprises the fluid discharge wall provided with at least one spay nozzle for discharging the pressurized cleaning fluid in at least one predetermined spray pattern that is directed to a finned heat exchange tube.

4. The cleaning system of claim 3 in which each of the plurality of interchangeable fluid compartments comprises a plurality of spray nozzles forming a spaced-apart array, each spaced-apart array of spray nozzles being aligned with finned heat exchange tubes to which they are adjacent when the spray head assembly is in an operable cleaning position on the ACHE.

5. The cleaning system of claim 1 in which the spray nozzles are separate units that are mounted in fluid-tight relation to an exterior surface of each of the interchangeable fluid compartments proximate the uppermost or lowermost tube bundle when the system is in operation.

6. The cleaning system of claim 1 in which slotted nozzles are formed in the fluid discharge wall by molding, cutting and/or drilling the fluid discharge wall.

7. The cleaning system of claim 1 in which each of the interchangeable fluid compartments has at least three transversely spaced spray nozzles, at least one of which spray nozzles discharges a spray of the pressurized cleaning fluid in a generally vertical direction to contact and pass through the uppermost or lowermost tube bundle.

8. The cleaning system of claim 1 in which the plurality of interchangeable fluid compartments are maintained in alignment by at least one longitudinal member positioned below the spray head assembly.

9. The cleaning system of claim 8 in which the spray head assembly is supported by a pair of longitudinal members, the opposite ends of each longitudinal member being securely joined in parallel relation by a transverse end member to form a rigid rectilinear supporting frame structure on which the spray head assembly is mounted.

10. The cleaning system of claim 9 in which the longitudinal members are further joined by a plurality of spaced-apart cross members at locations predetermined to be displaced from the spray nozzles positioned in the supported plurality of interchangeable fluid compartments.

11. The cleaning system of claim 1 further comprising a transport mechanism operably coupled to the spray head assembly, the transport mechanism including a drive motor and drive pulleys and activated by the drive motor to move the spray head assembly longitudinally adjacent to surfaces of the finned heat exchange tubes.

12. The cleaning system of claim 11 which further comprises a pair of parallel supporting tracks securely mounted on opposing housing side walls of the ACHE that are parallel to the longitudinal axes of the finned heat exchange tubes, the tracks being dimensioned and configured to receive the spray head assembly and transport mechanism, the tracks extending to a position at one or both ends of the ACHE in which the spray head assembly is displaced from an open region containing the uppermost or lowermost bundle when the spray head assembly is not in use.

13. The cleaning system of claim 12 in which the transport mechanism comprises wheels and the tracks are U-shaped, or C-shaped or L-shaped channels.

14. The cleaning system of claim 1, wherein each of the plurality of interchangeable fluid compartments abuts at least another one of the plurality of interchangeable fluid compartments.

15. The cleaning system of claim 1, wherein at least one of the plurality of interchangeable fluid compartments has a different size from another one of the plurality of interchangeable fluid compartments.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a top, front and right side perspective view of a conventional prior art air-cooled heat exchanger (ACHE) that includes an inlet header, outlet or return header and heat exchange tubes in a housing;

(2) FIG. 2A is a top, front and left end perspective view of an embodiment of a spray head assembly;

(3) FIG. 2B is a top, front and left end perspective view of another embodiment of a spray head assembly in accordance with this disclosure;

(4) FIG. 3A is a top, front and left side exploded perspective view of an embodiment of a top-filling fluid compartment for use in the spray head assembly of FIG. 2A;

(5) FIG. 3B is a view similar to FIG. 3A showing the right side of the compartments;

(6) FIG. 3C is a bottom view of the fluid compartment of FIGS. 3A and 3B that includes three transverse slot nozzles;

(7) FIG. 3D is an alternative embodiment of FIG. 3C in which three spray nozzles are fitted in a diagonal array in the bottom wall of a fluid compartment;

(8) FIG. 3E is a rear elevation of the fluid compartment of FIGS. 3A and 3B in which three nozzles extend from the bottom wall;

(9) FIG. 4A is a top, front, left side perspective view of another embodiment of a fluid compartment with side wall fluid passageways;

(10) FIG. 4B is a top sectional view of the fluid compartment of FIG. 4A taken along section line B-B;

(11) FIG. 5A is a front elevation view of another embodiment of a group of fluid compartments depending from a horizontal cleaning fluid delivery conduit;

(12) FIG. 5B is an end view of the compartments of FIG. 5A;

(13) FIG. 5C is a bottom view of the compartments of FIG. 5A;

(14) FIG. 6 is a partially exploded side and left end perspective view of the supporting frame member shown in FIGS. 2 and 2B;

(15) FIG. 7 is a top view, partly in phantom showing a portion of an ACHE fitted with the spray head assembly of FIG. 2B mounted on a mobile carriage connected to drive means for reciprocal movement to clean the finned heat exchange tubes; and

(16) FIG. 8 is a simplified perspective view of the ACHE and the embodiment of the cleaning apparatus of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(17) Referring now to FIG. 2, a spray head assembly (100) is comprised of a plurality of close-fitting rectilinear fluid compartments which are securely retained in a supporting frame (200) of a predetermined transverse width that extends across the upper surface of the finned heat exchange tube bundles (18) of the ACHE for which the spray head assembly is intended for use. The supporting frame (200) can advantageously be constructed from a pair of parallel L-shaped longitudinal members formed of steel that are linked at spaced-apart locations by a plurality of steel cross members (204) to provide a rigid construction. The ends of the longitudinal members (202) are secured together by transverse end members (206) which can be joined by any convenient means, including welding, threaded fasteners, rivets and the like. In order to provide means for lifting the supporting frame into position, at least two lifting brackets (220) each having a bracket opening (222) are secured to the exterior vertical surfaces of the opposing longitudinal members (202). As shown in FIG. 2A, the upper or free end of the lifting brackets (220) extend outwardly from the respective longitudinal members to which they are attached and from the fluid compartments placed in the supporting frame in order to permit hooks or other lifting devices to be placed in the bracket openings (222).

(18) In a preferred embodiment, the supporting frame (200) is provided with a plurality of fluid compartments (110), which are preferably of a uniform configuration and a width “W” to minimize inventory requirements. In order to accommodate ACHE units of different sizes and widths, e.g., that are not an even multiple of the fluid compartment, such as 10 times W, fluid compartments of ½ W (160) and ¼ W (170) are maintained in inventory to complete the spray head assembly and provide complete coverage of the tube bundles.

(19) With continuing reference to FIG. 2A, each of the standard size fluid compartments (110) and, if required for a particular ACHE, the smaller compartments (160, 170) is provided with an inlet fitting (128) that is received in an inlet port (126) that is provided in the top wall (112) of each of the compartments. As will be understood, the relatively smaller fluid compartments (160, 170) if required can be provided with inlet ports and inlet fittings that are proportionally smaller than those of the fluid compartments of the standard width W. However, to the extent possible, all parts and fittings, including the compartments, should be standardized for the reasons explained above. As will be understood by those skilled in the art, it is desirable to use standardized parts and fittings in the construction of the various components making up the assembly in order to minimize the types and sizes of spare parts that must be kept available for repairs and replacement during the life of the system.

(20) Positioned above the fluid compartments comprising the spray head assembly (100) is a fluid distribution manifold (180) that in the particular embodiment illustrated includes a manifold inlet (182) and a plurality of depending manifold discharge tubes (184), the free ends of which are each provided with fluid-tight fittings (186) that are configured and dimensioned to engage the inlet fittings (128) of the fluid compartments below. As illustrated, it will be understood that the manifold fittings that engage fluid compartments (160, 170) of narrower widths may be proportionally scaled to provide the required fluid-tight fitting when the pressurized fluid is introduced into manifold inlet (182) from an external source (not shown).

(21) For the purposes of illustration, the manifold discharge tubes (182) appear as rigid conduits. However, it will be understood by those of ordinary skill in the art that the manifold discharge tubes can be configured as flexible hoses with appropriate fluid-tight fittings (186) attached, e.g., by clamps or other known means.

(22) Any of various known types of fluid-tight fittings, such as quick-release hose fittings, can be used to couple the discharge manifold fittings (186) to the inlet fitting (128) of the fluid compartment to assure a fluid-tight coupling. The use of a flexible conduit for the manifold discharge tube (186) is desirable, since the manifold (180) will have to be attached and removed when the spray head assembly (100) and its supporting frame (200) are moved, e.g., initially placed for use on the ACHE and then removed for any eventual servicing of the unit. This manual task will be greatly facilitated by the use of quick-release couplings.

(23) The fluid compartments (110) illustrated in FIG. 2A are described in more detail with reference to FIGS. 3A and 3B which are views from two opposing sides (118 and 120) of an embodiment of the fluid compartment suitable for use in this disclosure. A suitable inlet fitting (128) is positioned above the inlet port (126) which as shown, are conventionally threaded. In an alternative, the parts can be coupled using a bayonet-type attachment, which can include a washer between the flange of the fitting and the top surface (112) of the fluid compartment (110). As will be understood by one of ordinary skill in the art, any of other well known arrangements for securing the fitting to the compartment can be substituted to effect a fluid-tight coupling.

(24) In a preferred embodiment of the system and apparatus, the close-fitting relationship and alignment of the compartments (110) on the frame is achieved by maintaining the dimensional tolerances during the manufacture of the compartments and of the assembly of the supporting frame (200) as described above. As is described in more detail below and in conjunction with FIG. 6, at least one end of supporting frame (200) is provided with an adjustable compression system or device for applying a compressive force to the aligned compartments (110) to securely maintain them in position during the cleaning operation.

(25) In an alternative embodiment shown in FIGS. 3A and 3B, the side wall (116A) can optionally be provided with projecting lugs (132) which will engage with recesses (134) in opposing side wall (116B) to assist in maintaining adjacent fluid compartments in secure alignment when placed in the supporting frame (200). Any other arrangement of interlocking elements on the opposing external faces of the fluid compartments can optionally be employed to achieve the desired result of maintaining the adjacent fluid compartments in alignment. This arrangement is particularly adapted for use when the individual compartments are produced using a corrosion resistant material, such as by molding of polymeric compositions, e.g., in a rotary mold using powdered polymer, which will provide compartments that are not subject to chemically-induced corrosion and/or fouling by airborne dust and debris. As shown in FIG. 2A, a fluid compartment (110) on an end of the assembly (100) can incorporate a blank side wall (116) without projecting lugs (132) or recesses (134).

(26) Referring to an alternative embodiment illustratively depicted in FIG. 3C, the bottom wall of the compartment (122) is provided with an array of three spaced-apart slot nozzles (125) that extend transverse to the axis of the ACHE finned tubes. In the embodiment shown, the three slot nozzles in effect triple the number of cleaning fluid sprays that impinge on the fins and tubes below. The spray slots can be chamfered, either inwardly so that the slot is narrower at the outlet, or outwardly flared.

(27) The patterns of the slot nozzles can be varied for a single compartment. The pattern and force of the spray discharged from the slot nozzles can also be varied by changing the pressure of the cleaning fluid supplied to the system. This variable can be determined by the operator based on experience, and can be dependent on a number of variable factors, such as the type and extent of fouling on the fins, the interval(s) between cleaning, the type and temperature of the cleaning fluid(s) and the like.

(28) In the embodiment of FIG. 3C, the slot nozzles can be integrally formed in the bottom wall of the compartment at the time of molding, or drilled and/or machined into the desired configuration to achieve the predetermined spray pattern for the molded unit. The same methods can be applied to forming integral single-point nozzles. These methods are well within the skill of the art and will not be described further.

(29) Referring now to FIGS. 3D and 3E, the bottom and side views, respectively of the compartment illustrated in FIGS. 3A, 3B, three spray nozzles (130) are shown extending in a diagonal array across the bottom wall (122) of the fluid compartment. In operation, a pressurized cleaning fluid is admitted into the compartment via inlet fitting (128) and discharged through the plurality of spray nozzles (130), the positions of which are predetermined to align with the finned tubes as the unit is transported down the ACHE. The spray pattern discharged by the nozzles (130) can be the same or different and can be selected to provide a wide area of spray, e.g., circular, oval and/or elongated, emitted from one or more of the plurality of nozzles in order to achieve the efficient cleaning of dirt and debris from the fins and the tubes of the tube bundles making up the array of the ACHE. The projecting lugs (132) and the corresponding recesses (134) described above are also shown in FIG. 3E.

(30) The slots can be of the same width and the nozzle exits can be of the same or of different configurations. For example, the opposing interior side walls of the slot nozzle can be parallel or slanted so that the discharge edge is either narrower than the compartment or intake side, or wider along the discharge edge to produce different spray patterns. Two or more different configurations can be used for the slots in a single compartment.

(31) As will be understood by one of ordinary skill in the art that the number of slots can be greater, or less, than three, e.g., a total of four or five slots. Factors such as the availability, volume, pressure and temperature of the cleaning fluid discharged on the finned tubes, as well as the type and amount of accumulated dirt and debris on the finned tubes will effect the design criteria of the present system.

(32) It will also be understood by one of ordinary skill in the art, the dimensions of the generally rectilinear compartments are not critical. In the interests of clarity and ease of description, the compartments shown in the attached drawings, with the exception of FIGS. 5A-5C described below, are depicted as being generally cubical to accommodate the various fittings in a scale that will facilitate a clear understanding of the structure.

(33) An alternative embodiment, for example, is schematically illustrated in FIGS. 5A, 5B, and 5C where each of the pressurized fluid compartments (110′) is relatively narrower in the dimension that corresponds to the axis of the finned tubes. Alternatively, one or more of the compartments can contain multiple internal fluid channels that terminate in, and define an individual slot (not shown). Each of the channels can include internal reinforcing supports extending between the opposing vertical walls to produce a robust construction. In an embodiment, the internal supporting walls are dimensioned and configured proximate the nozzle outlet to directionally dispose the cleaning fluid towards the tubes below. As best shown in FIGS. 5A and 5B, the compartments (110′) are in fluid communication with a rectangular manifold of the cleaning fluid delivery conduit (381) sealed at its ends and fitted with an inlet tube (383) through which pressurized cleaning fluid is admitted, e.g., as is shown and described in more detail in connection with FIGS. 2A and 2B. Referring to the bottom view of FIG. 5C, the bottom wall (122′) of each compartment (110′) is provided with a slot nozzle (125′) dimensioned and configured to discharge a spray onto the finned tubes.

(34) Another embodiment of the spray head assembly (100) for use in the system of the present disclosure will be described with reference to FIGS. 2B, 4A, and 4B. The top wall (312) and side (318) of fluid compartment 310 illustrated in FIG. 2B correspond in arrangement to top wall (112) and side (118) of the embodiment illustrated in FIGS. 2A, 3A, and 3B. In this arrangement, each of the fluid compartments (310, 360, 370) are provided with fluid passages (320) in opposing side walls (316A, 316B) that are aligned so that each of the plurality of fluid compartments shown in FIG. 2B have transversely aligned passages throughout the width of the supporting frame (200). Referring specifically to FIGS. 4A, 4B, a resilient annular seal (330) is shown positioned in the opposing passages (320). The annular seals are dimensioned and configured and are sufficiently resilient to deform and provide a fluid-tight seal when brought into a compressed relation with the seal of an adjacent compartment. The annular seals in the external walls of the fluid compartments at either end of the spray head assembly (100) are fitted with a resilient sealing plug (340) to maintain a seal against the pressurized fluid during use of the unit. The sealing plug (340) can be configured in accordance with methods well known in the art to assure that it is retained in place and maintains a fluid-tight seal when the assembly is pressurized with cleaning fluid—for example, in the interior chamber (326) of fluid compartment (310). The annular seals (330) can advantageously be of a molded silicone polymer that is chemically resistant and not subject to oxidation or other forms of deterioration which lead to a loss of resiliency.

(35) In an embodiment (not shown), the exterior side wall of the compartment (310) is recessed a predetermined amount to receive the exterior peripheral portion of the annular seal (330) during deformation to permit the facing exterior walls of the fluid compartments to be brought into touching relation. The interior flange of the annular seal is preferably dimensioned and configured to permit its deformation during insertion through the side wall passage (320) and then to return to its original configuration in order to provide the interior seal to retain the pressurized fluid.

(36) The fluid compartment (310) is provided with a plurality of openings (124) in the bottom wall (322) adapted to receive nozzles as described above in connection with FIG. 2A. It will also be understood that any minor fluid leakage between the annular seals (330) will not result in a significant drop in the fluid pressure and that the pressurized discharge from the cleaning nozzles will be maintained at a sufficient level to accomplish the desired degree of the cleaning of the fins and the tubes.

(37) Returning to FIG. 2B, a simplified manifold or charging conduit (380) comprises a manifold inlet (382), manifold outlet (384) and fluid-tight fitting (386). It will be understood from the above description of the fluid compartments (310) and their interconnecting fluid passages that only a single compartment inlet fitting (128) is required to pressurize all of the compartments in the spray head assembly.

(38) Referring now to the partially exploded view of the supporting frame (200), one embodiment of its construction is illustrated. It will be understood that the structural elements are fabricated from an appropriate gauge of steel or stainless steel to provide a sufficiently robust structure to support the fluid compartments which carry clean fluid to their capacity during the spray cleaning operation, and that the entire unit will be subject to additional stresses during reciprocating movement. The elements can be joined by welding, by threaded fasteners, rivets, either alone or in combination.

(39) An embodiment illustrating the installation of a spray head assembly (100) in accordance with FIG. 2B on a supporting frame (200) placed on a reciprocating wheeled carriage (500) will be described with reference to FIGS. 7 and 8. The wheeled carriage (500) is constructed from transverse carriage members (502) securely joined to longitudinal carriage members (504) which include structural members supporting a pair of wheels (510) at either side of the carriage. A pair of tracks (520) are secured to the upper surface of flange (22) extending horizontally from the side walls (16) forming the housing of the ACHE.

(40) A drive assembly positioned at an end of the ACHE that is preferably opposite the inlet and outlet headers includes an electric drive motor (560), a motor controller (562), a power supply (564) and a gear reducer (550). Drive shafts (552) extend from the gear reducer and are fitted with drive pulleys (540) that engage drive cables (530) attached to the transverse carriage member (502), or other suitable structural member of the carriage. The drive cables (530) can be of braided stainless steel construction or can take the form of a chain in which the pulleys are sprockets adapted to receive the chain in order to provide a more controlled movement and avoid any possible slipping of the pulley on a wet metal cable.

(41) As shown in FIGS. 7 and 8, the tracks (520) that are secured on the upper surface of the flange (26) are U-shaped channels which extend to a portion of the housing over the return header (12B). In the alternative, the tracks (520) can be in the form of L-channels or C-channels having arms dimensioned to maintain the wheels in position. This extension of the track (520) provides a storage location for the cleaning assembly that is out of the direct air flow of the cooling air that is passed through the tube bundles, thereby avoiding any loss in the efficiency or performance characteristics of the ACHE during its operation.

(42) As will be understood, the cleaning system could be used during operation of the ACHE where the air flow is downward through the tube bundles. In those plant installations where the cooling air fans are positioned below the elevated structure of the ACHE, the present cleaning system can be installed for operation in substantially the same configuration so that the cleaning fluid is passed from the cleaning nozzles upwardly in the same direction as the cooling air flow. Where the installation of the system is below the ACHE, the tracks will be supported on a separate assembly that is suspended from the ACHE structural members above. The manifold assembly is also positioned below the supporting frame (not shown).

(43) In either of the downwardly or upwardly discharge configurations, the manifold carrying the pressurized fluid from the remote source is conveniently fed by a flexible conduit, e.g., a hose, at least a portion of which travels longitudinally over the tube bundles with the cleaning system. Supporting and transport systems are well known in the art for maintaining the hose in the desired position during movement of the cleaning assembly.

(44) When the cleaning assembly is moved to the storage position, a protective cover (570) shown in phantom in both FIGS. 6 and 7 is provided to protect the unit from environmental conditions. The protective cover (570) can be fabricated from known materials and can be either permanently installed on the ACHE or configured as a portable unit that can be removed during cleaning operations and returned to supporting brackets or the like and secured there when the cleaning assembly is not in use.

(45) As best shown in FIG. 7, the supporting frame (200) is fitted at one end with a compressing apparatus (250) that is dimensioned and configured to apply a compressive force F to the exposed side wall of the adjacent fluid compartment (370) in order to maintain an abutting relation between the compartments in the assembly (100). As illustrated in FIG. 7, the compressing apparatus (250) comprises a compression actuator (252), here illustrated as a manually adjustable screw mechanism opposite a compression plate (254). As will be understood from the earlier description, the compressive force F functions in the embodiment of both FIGS. 2A and 2B, where it is important to maintain the fluid compartments immobilized in the desired position to assure the effective distribution of the spray from the nozzles onto the fins and tubes in the proper alignment. The compressive force F is particularly important for the embodiment of FIG. 2B in order to assure the compression and deformation of the annular seals to provide a fluid-tight passage between all of the compartments in the assembly.

(46) While the invention has been described in conjunction with several embodiments, it is to be understood that many alternatives, modifications and variations will be apparent to those skilled in the art based on this description. Accordingly, the scope of the invention is to be determined by the claims that follow.