US3068507A

US3068507A - Fluid heater cleaners

Info

Publication number: US3068507A
Application number: US51570A
Authority: US
Inventors: Evans Richard Henry
Original assignee: Babcock and Wilcox Ltd
Current assignee: Babcock International Ltd; Babcock and Wilcox Co
Priority date: 1959-08-28
Filing date: 1960-08-24
Publication date: 1962-12-18
Anticipated expiration: 1979-12-18

Description

Dec. 18, 1962 Filed Aug. 24, 1960 R. H. EVANS FLUID HEATER CLEANERS \x Ou E i (Darm Dec. 18, 1962 R. H. EVANS FLUID HEATER CLEANERS 2 Sheets-Sheet 2 Filed Aug. 24, 1960 United States Patent Ohee 3,@685'? Patented Dec. 18, 1952 FLUED HEATER CLEANERS Richard Henry Evans, London, England, assigner to Bahcocli 8.' Wilcox Limited, London, England, a company of Great Britain Filed Ang. 24, 1960, Ser. No. 51,570 Claims priority, application Great Britain Aug. 23, 1959 3 Claims. (Cl. 15-31'7) This invention relates to fluid heater cleaners of the kind comprising a nozzle tube adapted to be projected for operation from a retracted position.

The specification of United Kingdom patent specification No. 636,052 describes a fluid heater cleaner of the above kind and in which a nozzle tube is projected through a considerable distance which in practice could be up to say 27 feet.

lt has been found that when the construction of specification No. 636,052 is applied to nozzle tubes which require to be projected through an even greater distance, say 37 feet, the leading end of the nozzle tube, lwhich is unsupported, tends to deflect a greater amount than is permissible.

An object of the present invention is the provision of a fluid heater cleaner having a nozzle tube less subject to undesirable deflection of its outer unsupported end.

The invention includes a lluid heater cleaner including a nozzle tube So mounted as to permit the nozzle tube to be projected to an operative position over a substantial distance from, and returned to, a retracted position, wherein the nozzle tube is provided with an outer wall and an inner wall defining an axially extending annular passage between the two walls arranged for the passage of cleaning fluid flowing to the discharge nozzle or nozzles provided on the nozzle tube and diver-ted from a central region of the nozzle tube, whereby a desired velocity of flow of cleaning fluid over the inner surface of the outer wall can be obtained despite a relatively large cross sectional area of the bore of the nozzle tube.

The invention also includes a fluid heater celaner including an outer nozzle tube, and an inner cleaning fluid supply tube, the two tubes being telescopically arranged to permit the nozzle tube to be projected to an operative position over a substantial distance from, and returned to, a retracted position, wherein the nozzle tube is provided with an outer wall and an inner wall defining an axially extending annular passage between the two walls arranged for the passage of cleaning fluid flowing to the discharge nozzle or nozzles provided on the nozzle tube and diverted from a central region of the nozzle tube, whereby a desired velocity of ilow of cleaning uid over the inner surface of the outer wall can be obtained despite a relatively large cross sectional area of the bore of the nozzle tube.

The invention will nov be described, by way of example, with reference to the accompanying drawings, in which:

FEGURE l, which is partly diagrammatic, shows in side elevation and-with parts broken away the general arrangement of two adjacent similar fluid heater cleaners both embodying the present invention, but at different positions in their cycle of operation;

FIGURE 2 is a sectional side elevation of a nozzle tube shown in FIGURE l, but drawn to a much larger scale than in FiGURE l;

FGURE 3 is a transverse sectional view taken on the line lll-lll of FGURE 2;

FiGURE 4 is a transverse sectional view of part of'an I-beam and a feed tube shown in FIGURE 1 and illustrates an intermediate support member for the feed tube; and

FIGURE 5 is a sectional side elevation "taken on the line V--V of FIGURE 4 but with the parts in a diterent operative position.

Reference should be made to United Kingdom patent specification No. 636,052 for a full description of the construction and operation of the two similar

uid heater cleaners

1A and 1B shown in FIGURE 1. The present invention relates -to a modified form for the nozzle tubes 3 possessing advantages over the form of nozzle tube shown in that prior specification.

Briefly, the cleaner illustrated includes a nozzle tube 3 which may be advanced through an aperture in a wall 5 of the casing of the fluid heater with which the cleaner is associated, from the retracted position of the upper cleaner 1A of the two similar cleaners illustrated in FIG- URE 1 to the advanced position of the lower cleaner 1B. The inner end of the nozzle tube is provided with nozzle apertures 7 arranged symmetrically around the circumference, two such apertures being provided in the construction shown. In operation, the nozzle tube 3, while supplied with cleaning uid, is advanced between rows of the tubes 9 which are to be cleaned, and is at the same time rotated about its longitudinal axis, so that' cleaning uid issuing from the nozzle apertures 7 scouts the outer surfaces of the tubes 9. Having reached the advanced position, the nozzle tube is retracted, rotating now in the opposite direction.

Cleaning uid is supplied to the nozzle tube 3 from a supply pipe 11 which is secured to the inlet of a pressure part 13 in the form of a valve chest. The outlet 1S from the pressure part 13 has connected to it a feed or supply tube 17. The feed tube is arranged telescopically within the nozzle tube 3.

The nozzle tube is sup-ported near the wall end of the part thereof outside the casing wall 5 within a bracket 19, through which it extends. This bracket is provided in its lower part with two freely rotatable rollers 21 which are arranged slightly on the skew with respect to the nozzle tube so that as the latter rotates and at the same time progresses axially a proper rolling action takes place between the nozzle tube and the rollers. The bracket 19 is in turn supported from a beam 23 of I-section extending above and parallel to the longitudinal axis of the feed tube 17 and itself suitably supported.

The nozzle tube 3 is supported near its outer end in a carriage 25 arranged to run on a track plate 26 secured to the underside of the beam 23.

rEhe nozzle tube 3 has secured to its rearmost end by welding, as indicated at 27 in FIGURE 2, an annular terminal member 29 part of which extends within the nozzle tube 3, and part of which is shaped as a portion of a sphere and is arranged to engage two annular packing rings shown and described in detail in the above mentioned specification No. 636,052. These packing rings are seated in a counter bore at the forward end of a gland member carried by the carriage 25. A fluid tight sliding connection between the feed tube 17 and the gland member is provided by a compressed packing. A motor 31 is mounted on the carriage 25 and effects movement of the carriage along the beam 23 and, through the two annular packing rings mentioned above, rotation of the nozzle tube 3 about its axis.

In the construction set out in the prior specification, cleaning fluid issuing from the open forward end of the feed tube continues to ilow forwardly, along the nozzle tube, towards the nozzle apertures. In the modified cleaner of the present invention, the nozzle tube 3 includes a liner in the form of a tube 33 having a closed forward end 33A and provided at spaced locations about its periphery and along its length with outwardly extending projections 35 by which it is maintained in spaced relation to the outer nozzle tube 3. As will be seen from FIG- URES 2 and 3, an annular space 37 is bounded by the inner surfaceofthe outer nozzle tube 3 and the outer surface of the liner tube 33 and communicates at its forward end with the part of the outer nozzle tube provided with the apertures. 7 and at its rearward end with a further annular space 39 bounded by the inner surface of the liner tube 33 and the outer surface of the feed tube i7. A flow path for cleaning huid is thus established extending forwardly through the feed tube 17, rearwardly through the annular space 39, and forwardly through the annular space 37 and to the apertures 7.

The projections 35 are in the form of small, shaped metal blocks extending through oblong holes cut in the liner tube 33 and welded in place. The parts of these blocks outside the liner tube are so shaped as to ,iam against the inner surface of the nozzle tube 3 and hold the liner tube against rotary and longitudinal movement relative tothe nozzle tube. lf desired, as a precaution against the forces set up by the flow of cleaning fluid causing displacement of the liner tube 33` towards the front end of the outer nozzle tube, where it could close the front end of the annular space 37a metal bar il can be weldedto the front end of the liner tube 33, this bar being of such a length that upon forward movement of the liner tube the bar will butt against a sloping inner surface 3B of the outer nozzle tube and prevent movement of the liner tube 33 to a position in which the space 37 is blocked at its forward end.

The partsof the blocks 40 which extend inside the liner tube 33 are formed each with a radially inwards surface 43 which slopes inwardly and forwardly to a crest portion 45.' When the nozzle tube 3 is in its withdrawn position, as shown for cleaner 1A in FIGURE l and as shown in FIGURE-2, the crest portions 45 engage the feed tube 17 and support it centrally of the nozzle tube 3; When the nozzle tube 3 is moved rearwardly from the advanced position'shown for cleaner 1B in FIGURE 1, the sloping surface 43 on each block 49 causes the block to ride up onto tA e outside of the feed tube i7 without fouling its forward end.

During use of the uid heater cleaner described above, the flow of cleaning fluid through the annular space 37 ensures that the nozzle tube 3 will remain at a relatively low temperature despite its exposure to high temperature gases flowing through the gas pass containing the fluid heater.

By the selection for the radial width of the annular space 37 of a suitable value, the velocity of flow of the cleaning fluid flow over the inner surface of the nozzle tube 3 can be maintained at a desired high value, no matterl how large the diameter of the nozzle tube 3. This is i in contradistinction to the conditions in the nozzle tube of the prior specification mentioned above in which, for any given mass flow of cleaning fluid, the velocity of the cleaning fluid through the nozzle tube varies inversely asth-e square of the internal diameter of the nozzle tube.

The rigidity of the nozzle tube as a cantilever beam varies with its diameter and its working temperature. With the construction of the prior specification, an increase in the rigidity promised by an increase in the diameter of the nozzle tube 3 is countered by a decrease in the rigidity due to the increased working temperature of the nozzle tube consequent upon the reduced efficiency of the cleaning fluid in effecting cooling of the nozzle tube. As a result, a limit is found beyond which an increase in the diameter of the nozzle tube no longer provides an increase in the rigidity of the nozzle tube.

By the provision of the liner tube 33 and the diversion -of all the cleaning iluid to flow through the annular space between the liner tube and the outer nozzle tube, the effectiveness of the cleaning fluid as a cooling medium is improved, and the diameter of the outer nozzle tube may be considerably increased before the increased heat absorption by the larger surface area of the tube reaches a value too great for the limited amount of cleaning iluid available to effect sucient cooling of the nozzle tube.

Ffue provisionof a more rigid nozzle,l tube permits the use of longer nozzle tubes in situations where the amount of liezure of the free forwardl end of the nozzle tube is limited by the spacing of the heat exchange tubes between which it is to extend and in situations where the limiting factor is the ability of the nozzle to withstand the reaction of the discharge of cleaning fluid from a non-symmetrical arrangement of apertures on the nozzle tube.

A secondary problem which arises when a very lengthy nozzle tube is used is the support of the feed tube 17. rfhe feed tube 17 is supported at its rearward end by the pressure part i3 and at some other point by the sliding gland, but since that sliding gland moves over the outer surface of the feed tube it cannot be providedwith any fixed support over a length at least as large as the. distance through which the nozzle tube 3 moves forwardly. The blocks di) described above provide support of the feed'tube 17 at spaced points along its whole. length when the nozzle tube 3 is fully retracted, and over a forward part of its length when the nozzle tube is partly advanced. This intermediate support is most important during retraction of thenozzle tube, since in the absence of any such support the forward end of the feed tube will sag onto and rest upon the inner surface of the liner tube 33, and tend to scuif that tube as it moves rearwardly.

Whenthe nozzle tube is fully advanced, the feed tube l is supported at its rearward end by the pressure part 13 and near its forward end by the sliding gland, and if unsupported will tend to sag at its mid-length unless it is made of large; diameter and thus rigid. A large diameter feed tube is undesirable since it necessitates the use of a large sliding gland and a general increase in the size of the paris ofthe uid heater cleaner. FIGURES 4 and 5- show a simple intermediate support'member 51 which, when the nozzle tube 3 is in its retracted position, is carried by a rearward projection 53 provided on the carriage 25, but, as the nozzle tube reaches a predetermined position in its forward movement, is stopped by two abutments 55 fixed to the I-beam 23 and left behind by the nozzle tube to act as anY intermediate support for the feed tube 17.

The support member 51 is in the form of a plate formed with an aperture 57 the lower end of which is shaped to accommodate the feed tube 117 and the upper end 57A of which is horizontal but rounded along its edges. At its upper end the plate is formed with an aperture 59 in which lies the lower part of the l-beam 23A and the track plate, this aperture having two shoulders til respectively on opposite sides of l-beam 23 which can engage the upper surface of the track plate so that the support member Sik is supported by the track plate. The depth of the aperture 59 is such that the support member can be moved up to the position shown in FIGURE 5 so that the shoulders 6l disengage from the track plate. Above these shoulders the support member is provided with two inwardly facing lugs 63 arranged to engage respectively the two abutments 55. The rearward projection 53 is slightly narrower than the upper end of the aperture 57 and its upper surface includes a horizontal part 53A adjacent the carriage 25 and a downwardly and rearwardly sloping part 53B disposed rearwardly of the part 53A. In FIGURE 4 is indicated the position of two forwardly facing abutments 65 which are provided on the front face of the pressure part 13 and lie on opposite sides of the aperture 57 level with the projection 53.

in use of the fluid heater cleaner fitted with such an intermediate support, as the nozzle tube 3 moves forwardly the support member 51 engages the abutments 55 and is left behind by the forwardly moving nozzle tube. Initially the support member is lowered as the upper end 57A of the aperture 57 slides down the sloping part 53B of the projection 53. This downward movement is stopped by engagement of the shoulders 61 with the upper-surface of the' track plate Z6. Since the feed tube 17 is still supported adjacent the support member 51 by the sliding gland of the carriage 25, the feed tube 17 is still spaced from and unsupported by the support member. As the carriage and the sliding gland moves away from the support member 51, the feed tube 17 commences to sag, and cornes into contact with the shaped lower end of the aperture 57, by which it is supported.

During retraction of the nozzle tube 3, first the feed tube 17 is lifted from the support member 51 as the sliding gland moves towards the support member, then the projection 53 enters the aperture 57, and iinally the projection 53 lifts the support member out of contact with the track plate to ytravel rearwardly with the carriage and the nozzle tube. It will be seen that no sliding movement takes place between the support member and either the track plate or the feed tube. It may happen that the support member 51 does not rise fully onto the part 53A of the projection 53; however, as the support member 51 approaches the pressure part it will be engaged by the projection 65 if it is not properly on the projection 53, and the terminal part of the movement of the carriage 2S will ensure that the support member is properly positioned on projection 53.

In the case of a very long feed tube 17, a plurality of support members 51 can be provided on a single projection 53 with the abutments 55 and the lugs 63 of the various support members arranged so that the support mentbers are rendered operative one after the other by continued forward movement of the blower tube 3. This is readily arranged by a suitable selection of the transverse distance between lugs 63 and of the widths of the a-butments 55.

What is claimed is:

1. A uid heater cleaner :comprising a nozzle tube, an inner, cleaning fluid supply tube arranged telescopically inside the nozzle tube, a nozzle tube mounting accommodating the nozzle tube to permit it to be projected from a retracted position outside a gas pass of a vapour generating unit to an operative position in the gas pass 'and returned to the retracted position, means -for moving the nozzle tube between the retracted and projected positions,

the nozzle tube including an outer nozzle tube and a thin, inner liner tube having a closed leading end remote from the end through which the supply tube passes and provided with projections arranged to space the liner t-ube from the outer nozzle tube to define an axially extending annular passage Abetween the outer nozzle tube and the inner liner tube extending along substantially the whole of the part of the nozzle tube which, when the huid heater cleaner is installed and the nozzle tube is yfully projected to the operative position, lies within the gas pass, and at least one discharge nozzle provided -on the outer nozzle tube beyond the leading end of the liner tube, the supply tube supplying cleaning fluid to the interior of the nozzle tube to pass along the axially extending annular passage to the said discharge nozzle, whereby in use the desired velocity of flow of cleaning uid over the inner surface of the outer nozzle tube can be obtained despite the relatively large cross sectional area of the bore of the outer nozzle tube.

2. A fluid heater cleaner according to claim 1, in which the projections extend through the liner tube, radially outer portions of which projections are arranged to maintain the liner tube in suitably spaced relation to the outer nozzle tube and radially inner portions of which projections -are arranged to maintain the part of the supply tube within the inner liner tube centrally of the inner liner tube.

3. A uid heater cleaner according to claim 2, in which the radially inner portions of the projections provided on the liner tube are shaped at their radially inner ends to provide ramp-like surfaces facing toward a free end of the supply tube as the nozzle tube is being retracted, whereby entry of the free end of the supply tube between the projections is facilitated.

References Cited in the file of this patent UNITED STATES PATENTS 606,093 Semke June 21, 1898 690,474 Snyder Ian. 7, 1902 2,324,785 Linaker July 20, 1943 2,668,978 DeMart Feb. 16, 1954