US3593691A

US3593691A - Wide jet soot blower

Info

Publication number: US3593691A
Application number: US819755A
Authority: US
Inventors: Herbert Wirths; Hugo Caldewey
Original assignee: L&C Steinmueller GmbH
Current assignee: Hitachi Zosen Inova Steinmueller GmbH
Priority date: 1969-04-28
Filing date: 1969-04-28
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20

Abstract

A method of cleaning a cooling pipe wall in fire and radiation chambers of boilers by means of a steam-operated wide jet soot blower having rearwardly directed blow nozzle means. A blowpipe is adapted to be advanced away from and retracted into the cooling pipe wall linearly during rotation simultaneously occurring to direct the nozzle means along a rotating path. There are steps of moving the blower with the nozzle means thereof closed in a direction linearly away from the pipe wall to a location representing approximately the intended maximum distance of the blower from the pipe wall to be cleaned, opening the nozzle means only when the blower has reached the location, and subsequently moving the blower with the nozzle means open along linear distance during rotating that results in directing the nozzle means in a rotating path back toward and into said wall while closing the nozzle means when the blower during its simultaneous linear and rotating movement back toward the wall has reached a desired safety distance from the wall.

Description

United States Patent Gummersbach (Rhineland), Germany [54] WIDE JET SOOT BLOWER 2 Claims, 3 Drawing Figs.

[52] US. Cl l22l30 [51] lnt.Cl F22b 37/48 [50] Field ofSeai-ch .4 122/390,

[56] References Cited UNITED STATES PATENTS 2,722,033 ll/l955 Glinn et al. 122/392 2,737,681 3/1956 Elmendorfm, 15/318 3,344,459 10/1967 Jankowski 15/317 l I w Primary Examiner Kenneth W. Sprague Attorney-Walter Becker AMSTRACT: A method of cleaning a cooling pipe wall in tire and radiation chambers of boilers by means of a steamoperated wide jet soot blower having rearwardly directed blow nozzle means. A blowpipe is adapted to be advanced away from and retracted into the cooling pipe wall linearly during rotation simultaneously occurring to direct the nozzle means along a rotating path. There are steps of moving the blower with the nozzle means thereof closed in a direction linearly away from the pipe wall to a location representing approximately the intended maximum distance of the blower from the pipe wall to be cleaned, opening the nozzle means only when the blower has reached the location, and subsequently moving the blower with the nozzle means open along linear distance during rotating that results in directing the nozzle means in a rotating path back toward and into said wall while closing the nozzle means when the blower during its simultaneous linear and rotating movement back toward the wall has reached a desired safety distance from the wall.

WIDE JET SOOT BLOWER The present invention relates to a wide jet soot blower and a method of operating the same. The invention concerns in particular push or wide jet soot blowers which are employed for keeping clean the walls of cooling pipes in fire and jet chambers of boilers preferably heated by coal and which are arranged axially displaceable and rotatable in a protective pipe which extends through the outer boiler wall covered by cool ing pipes, with the axis of said protective pipe substantially perpendicular to said outer wall surface.

With wide jet blowers of this type, the blowing head equipped with rearwardly directed steam blowing nozzles is in rest condition relatively cool and is located within said protective pipe. According to one embodiment of such soot blowers, the soot blower is for purposes ofcleaning blowing moved out of said wall while simultaneously rotating about its longitudinal axis into the fire or jet chamber to a certain maximum end position and subsequently is returned into said protective pipe. The nozzles arranged in said blowing head will, during this blowing operation, carry out a rotating movement.

With this embodiment, the blowing valve was expediently opened simultaneously with the moving outwardly of the blowing head into the fire chamber while, however, always a a a certain safety minimum space was maintained between the blowing head or the blowing nozzles thereof and the surface of the cooling pile wall to be cleaned.

In spite of this safety measure, frequently already during the first month of operation outer tears and damage were observed on those boiler pipes which were located in the immediate vicinity of the soot blower. Such tears and other damage could not be completely avoided even by increasing the said safety distance.

Further investigations have shown that these pipe damages were caused not by the hot steam employed for the blowing operation but are due to the condensate which collected during the rest position and in particular during the warming of the blower and the steam pipes leading thereto.

It is, therefore, an object of the present invention to provide a wide jet soot blower which will overcome the above-mentioned drawbacks.

It is another object of this invention to provide a method of operating a wide jet soot blower which will result in avoiding the above-outlined drawbacks heretofore encountered with wide jet soot blowers.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. I is a cross section through the wall of a wide jet soot blower in a plane which contains the blower axis;

FIG. 2 diagrammatically illustrates the pertaining lateral view of the wall surface;

FIG. 3 shows a soot blower which is particularly well suitable for use in connection with the present invention.

The invention is based on the observation that when opening the blowing valve, the immediately pushed out condensate first enters the fire chamber in the form of a rather compacted jet and then after a certain distance from the blower dissolves itself into a cloud of fine water droplets which no longer do damage to the pipes hit thereby.

With heretofore-known wide jet blowers which are provided with a blowing head rotating in the same sense of rotation and at constant angular speed and the steam nozzles of which are blowing in rearward direction onto the cooling pipes which are to be cleaned and pertain to the respective fire chamber wall, the length of the blowing jet decreases from the start of the blowing with increasing path of the blowing head until the blowing head has reached its outermost end position in the firechamber approximately corresponding to the radius of an Archimedes spiral. The length of the blowing jet is thus with fully moved out blow head greater by a multiple than when passing the above-mentioned relatively short safety distance.

Inasmuch as the destructive effect of the quantities of condensate contained in the steam jet considerably decreases with increasing length of the blowing jet, and inasmuch as due to the constant angular velocity of the blow head, the effective time or duration ofthe blow jet, with regard to the wall surface unit, decreases with increasing blowing radius, it will be evident that according to the present invention a double safety against the erosions caused to the cooling pipes by the steam condensate will be realized because the force as well as the duration of the condensate jet per surface unit of the cooling pipes will be considerably reduced.

The above-outlined inventive idea can be realized in a particularly simple manner with that type of heretofore known blowers in which the blowing pipe, for instance, by means ofa thread-shaped guiding arrangement moves forwardly and rearwardly along a rotating path and is preferably rotated by a gear driven from the outside while said blowing pipe is axially displaceable relative to said gear, and in which said blow pipe is first moved along a rotating path forwardly into the fire chamber while, when exceeding the safety distance, the blow valve is opened, whereupon when, during its further outward movement the blow head reaches its end position in the fire chamber, the direction of rotation of the blow head relative to the stationary housing is reversed whereby the return movement is initiated. Simultaneously, the blow valve closes and the blow head returns to its end position into the protective pipe in the wall. With this design, the rotating movement of the blow pipe may, of course, also be effected by other means, for instance, by mounting the same between inclined rollers.

Inasmuch as the automatic control of the individual operations of the entire working cycle is effected by the cooperation of a control disc connected to the end of the blowing pipe and having an annular shape, if desired, provided with a flange with a control rail which is tiltably journaled in a housing and axis parallel to the blowing pipe, it will be possible for the average expert in the field familiar with the blower construe tion also expediently to adjust or change the actuation of the control disc and control rail when reversing the originally provided turning direction. The control rail acts upon the blowing valve and the electric control switches for the motor drive of the blowing pipe.

The operation of the blower will now be described in con nection with the movement of the blowing head and the range of actuation of the blowing jet. Specifically referring to the drawing, the fire wall is covered by cooling pipes R which are arranged closely adjacent to each other and are passed through by the boiler working medium. A protective pipe R, extends through said wall of cooling pipes in a direction substantially perpendicular to the wall surface formed by said cooling pipes. Within the protective pipe R, there is guided the blowing pipe of the blower, which blowing pipe has its outer end provided with the blowing head K whereas the blowing pipe when in rest position is protectively arranged within said protective pipe R,

That plane which is parallel to the wall of cooling pipes and is tangent to the cooling pipes R while being located on the side of the fire chamber is designated with the reference character W. It is from this surface W that the decisive axial distance of the blowing head or steam nozzles thereof is measured for the blower when the latter is in operative position. In particular, the minimum or safety distance a, is important because it must not decrease during the operation, i.e. while steam leaves the nozzles. The maximum distance of the blower reached in the end position of the latter is designated as a,,,,,,, and shown in FIG. 1.

The true length of the blow jet is, of course, in conformity with the magnitude of the angle of inclination of the blow nozzle with regard to the blowpipe axis considerably greater, however, always proportional to the respective axial distance a of the blow head from the plane of the wall. The true length of the blow jet corresponds to the straight lines leading from the points 0. l, 2 and 3 of the wall surface to the corresponding centers of the blow head.

FIG. 2 shows the Archimedes spiral 1 -2 3 which is described by the blow jet (reduced to its center line) on the wallsurface during the actual blowing. in conformity with the invention, the blow head (when the blow valve is closed) will first in a direction opposite to the direction indicated by the arrows move along a rotating path simultaneously with linear movement out of the wall formed by the cooling pipe R and when reaching its outermost end position with the axial distance a,,,,,, will open the blow valve and at the same time will reverse its sense of rotation so as to move in the direction indicated by the arrows. The condensate shock occurring each time when starting the cold blower will thus move over the longest possible blowing path before impacting upon the cooling pipes.

Subsequently, the blowing pipe (in conformity with the illustrated example with three complete revolutions) moves, while blowing, back to point 3 into the wall; then, when passing point 3 or the axial distance a,, the blow valve is closed and when reaching the innermost (not illustrated) end position, the blowpipe comes to a rest at which time also the blow head is located completely within the protective pipe R, and is shrouded against any heat radiation from the fire chamber.

FIG. 3 shows a soot blower type for realizing the present in vention. More specifically, the soot blower of FIG. 3 comprises a blowpipe B provided over a limited length with an outer thread Ga. The free inner end of said blowpipe B carries the blow head K and when turned in one direction moves into the fire room while when being turned in the opposite direction it moves out of the fireroom.

Blowpipe B is concentrically surrounded by a gear Z having an inner bushing C and being adapted to be rotated in either direction by a reversible electric motor M through the inter vention of a pinion D.

That longitudinal portion of blowpipe B which is provided with an outer thread Ga is guided in a threaded sleeve Gi (inner thread) of the stationary blower frame, whereas the outwardly adjacent blowpipe portion is up to control discs S provided with tongues extending in axial direction and engaging the axial grooves of bushing C.

The entire blowpipe is in a rest position within a protective pipe R, which extends through the boiler wall. At the outer end of the movable blowpipe there is fixedly arranged a circu lar control disc S which when the blow head freely extends into the fire chamber, with its circumference moves in a sliding manner below a control rail L over the entire length thereof and, in view of its turning movement (in one direction only of the two directions of rotation) pivots laterally about an axis parallel to the blow pipe whereby by means ofa linkage the blow valve V of the blower is opened and during the contact between control disc and control rail L is kept open.

This arrangement thus brings about that the blower valve will be open only as long as the blow head passes through a certain area in the fire chamber in a certain direction of rotation.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawing but also comprises modifications within the scope of the appended claims.

What we claim is:

1. A method of cleaning a cooling pipe wall in fire and radiation chambers of boilers by means of a steam-operated wide jet soot blower having a rearwardly directed blow nozzle means and being equipped with a blowpipe adapted to be advanced linearly away from and retracted into said cooling pipe wall while nozzle means move along a rotating path, which includes the steps of moving said blower with the nozzle means thereof closed away from said pipe wall to a location representing approximately the intended maximum distance of said blower from the pipe wall to be cleaned, opening said nozzle means when said blower has reached said location, and subsequently moving said blower with said nozzle means open along a path back toward and into said wall linearly while closing said nozzle means durin rotation when said blower during its movement linearly bac toward said wall has reached a desired safety distance from said wall so that pipe damage otherwise caused by initial hot steam condensate is avoided.

2. An apparatus for cleaning a cooling pipe wall in fire and radiation chambers of boilers, which includes: a wide jet soot blower comprising a blow pipe with a blow head having blow nozzle means adapted and closed, driving means operatively connected to said blow pipe and operable to move said blow pipe linearly while said nozzle means move along a rotating path in the rotation direction with said nozzle means in closed condition, and control means operatively connected to said blow head and said nozzle means and operable in response to said blowpipe having reached a desired maximum distance from the pipe wall to be cleaned to reverse the movement of said blow pipe while causing said nozzle means to open and subsequently to close in response to said blowpipe reaching a desired minimum distance from the pipe wall to be cleaned so that pipe damage otherwise caused by initial hot steam condensate is avoided.

Claims

1. A method of cleaning a cooling pipe wall in fire and radiation chambers of boilers by means of a steam-operated wide jet soot blower having a rearwardly directed blow nozzle means and being equipped with a blowpipe adapted to be advanced linearly away from and retracted into said cooling pipe wall while nozzle means move along a rotating path, which includes the steps of moving said blower with the nozzle means thereof closed away from said pipe wall to a location representing approximately the intended maximum distance of said blower from the pipe wall to be cleaned, opening said nozzle means when said blower has reached said location, and subsequently moving said blower with said nozzle means open along a path back toward and into said wall linearly while closing said nozzle means during rotation when said blower during its movement linearly back toward said wall has reached a desired safety distance from said wall so that pipe damage otherwise caused by initial hot steam condensate is avoided.