US 3045978 A
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July 24, 1962 R. WALDHOFER Filed May 2, 1960 2 Sheets-Sheet 1 CLEAN ING STEAM ca/vffaL ROG'M) .10 H
TIME .17 IPA-119V OUTLET a COOLING l l para/mane WATEBJO J4 ;MOT2 Mam/s INLET COOL1NG REDUCING GIL/U2. F 1 WATER 1 -3- "5% .9 I 50 I a? 25 21 I II I 24 3 l I i 6 7 a X a K R HEAT EXCHANGE-E JACKET IN V EN T OR. .26 1757/19/90 WAL OHOFER July 24, 1962 WALDHOFER 3,045,978
TUBULAR BOILER OR HEAT EXCHANGER WITH SOOT BLOWER Filed May 2, 1960 2 Sheets-Sheet 2 IN V EN TOR. Pal/401.0 mu anon-2.
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s 7- roxzm/srr United States Patent 3,045,978 TUBULAR BOILER OR HEAT EXCHANGER WITH SOOT BLOWER Reinhard Waldhofer, Essen-West, Germany, assignor, by
mesne assignments, to Koppers Company, Inc., Pittsbugh, Pa., a corporation of Delaware Filed May 2, 1960, Ser. No. 26,039
2 Claims. (Cl. 2571) The invention relates to a tubular boiler or heat exchanger especially for oil and powdered fuel gasification plants with a soot blower provided with a movable blast rack.
Soot blowers with a blast rack which are reciprocally movably arranged above the tubes of the heat exchanger are known for cleaning the outside surfaces of the tubes of deposits of soot.
It is also known that the inside surfaces of the tubes of heat exchangers can be cleaned by axially movable and rotary soot blowers, in which case the soot blower is introduced into each individual tube of the nest of tubes. Such a soot blower requires not only a multiple drive for the radial, axial and transverse motion to the individual tubes but also requires a considerable loss of time for a satisfactory cleaning.
The time intervals between the cleaning of the tubes of deposits of soot should not be too great in order to prevent the soot deposits from hardening; they can then no longer be blown out but must be removed in difiicult scraping operations.
According to the invention the tubes of cylindrical tubular boilers and/0r heat exchangers, through which gases containing soot flow, are cleaned by means of a soot blower which consists of a feed pipe which is rotatably arranged in the axial center of the nest of tubes and is transversely connected with a radially extending blast rack. The feed pipe is turned with the blast rack sweeping about said axial center over the nest of tubes at a rather low speed so that all the tubes are flowed through by the cleaning fluid such as gas or steam and are cleaned after at least one revolution.
According to the invention the pipes supplying the cleaning steam or gas are covered in known manner by a water-cooled jacket in order to protect the pipes from the high temperatures of the flue gas or distillation gas.
In order to prevent the steam or the cleaning gas to be blown through the tubes of the tubular boiler and heat exchanger from hitting the tube sheet that supports the tubes and thereby destroying a part of the energy, the invention further provides for equipping the pipe tube sheet on the side thereof for introducing the cleaning gas or steam to the tubes with a plate in which are arranged openings which are conically tapered to converge towards the tubes and whose confines terminate sharply on their inlet sides. In this way it is possible for the nozzles of the rotary blast rack to blow the steam or the gas with certainty in all of the tubes to be cleaned without a noteworthy portion of the kinetic energy being destroyed.
Finally, the invention also consists in connecting the drive motor of the soot blower with a control by which the drive motor is automatically connected and disconnected from the central control room at regular time intervals, for example by a time relay. In this way a certainty is provided that the cleaning process also takes place in the time interval necessary for an easy blowing away of the soot.
This automatic operation of the cleaning of the tubes is of special advantage in large plants with several tubular boiler or heat-exchange units which are subsequently connected to each gasification unit, for example in oil or powdered fuel gasification plants.
3,045,978 Patented July 24, 1962 The invention is illustrated by way of examples in the drawings, in which:
FIGURE 1 illustrates a partial vertical section through a heat exchanger with a soot blower embodying the invention; and
FIGURE 2 shows on an enlarged scale the lower part of the blast rack in the heat exchanger.
Heat exchanger 1 consists of a cylindrical row of vertical tubes 2 which are gastightly arranged in tube sheet 3 in a tubular jacket. The space between the tubes and the jacket of heat exchanger 1 is filled with a cooling medium, for example water, which absorbs the heat of the hot gas flowing through pipes 2. Steam is produced by the heating of the water, steam is superheated in a receiver 4 arranged thereover, for example, in a tubular system located therein (not illustrated). The soot containing gas is introduced at 5 to the receiver 4. Cooling jackets 32 and 33 constitute the side walls of the apparatus above tube sheet 3.
Tube sheet 3 is provided with a plate 6 which is fitted to the cylindrical cross-section of the jacket of the heat exchanger 1. Openings 7 which are conically tapered to converge towards tubes 2 are provided in the plate 6. The conical openings 7 are widened toward their inlet sides so that they terminate sharply at 8. In this way neither deposits of soot can be formed on the tube sheet between the individual tubes, nor can the cleaning gas injected for blowing out tubes 2 rebound on obtuse surfaces and destroy a part of the energy of the stream.
A feed pipe 9 for inlet of the cleaning steam which is supplied at 10 above the receiver 4 is arranged in the vertical central axis of heat exchanger 1. At a short distance from tube sheet 3 or plate 6 the feed pipe 9 is radially connected with a radially extending blast rack 11. The blast rack 11 is provided with nozzles 12 which are directed towards the mouths of tubes 2. The blast rack 11 projects freely in a cooling jacket 13 through which flows a cooling medium, for example water. Feed pipe 9 is covered in the same manner by a cooling jacket 14 which is not illustrated in great detail. Cooling jacket 14 is connected with cooling jacket 13 of blast rack 11. The cooling water is supplied to cooling jacket 14 at 15, then flows through one of two sections subdivided by separating wall 31, FIGURE 2, towards the bottom, flows at the end 16 of cooling jacket 13 surrounding blast rack 11 into the other section of the cooling jacket, and finally flows out through elbow 17 above the receiver 4. The heated cooling water discharged at 17 is preferably used for feeding the heat exchanger 1.
The cooling jacket 13 is formed by two axially divided pipe halves between which partition 31 is inserted by welding. The blast rack 11 is rotated at. the beginning of the operation for blowing out of the tubes 2 of the heat exchanger by rotating the supply pipe :9 together with cooling jacket 14. The drive for this rotary motion is effected by means of an electric motor 18 through a reducing gear 19, the shaft 20 of which acts by means of a pinion 21 on a toothed wheel 22 for rotating feed pipe 9 together with cooling pipe 14. The toothed wheel 22 is provided with a smooth bearing piece 23 which rests on rollers 24. The radial counterpressure is absorbed by horizontal rollers 25 adjacent to the radial perimeter of the smooth bearing piece 23 of toothed wheel 22.
The inlet and outlet pipes 15, 17 for the cooling water are fastened to stationary housings 26, 27 which form an annular space 28 in the vicinity of pipes 15, 17; annular space 28 is communicably connected with the cooling water space of cooling jacket 14 by a slit 29. The housing 26 is sealed against the escape of cooling water by stuffing boxes 30 arranged at each end.
The starting of motor 18 for rotating blast rack 11, and the introduction of the cleaning steam or gas through line 10 are effected from a central control room automatically at intervals of about 2 hours by means of a time relay, a magnetic valve, or any similar automatic shut-off means operated from a distance. The transmission ratio of gear 21 is such that the blast rack 11 makes about 1.4 revolutions in one minute.
1. Heat exchange apparatus for transfer of heat to Water from oil .and powdered fuel gasification systems, comprising a combined cylindrical nest of vertical tubes disposed in a water jacket, a chamber disposed above the upper ends of the vertical tubes, an upper tube sheet disposed within the chamber and secured gas tight to the upper ends of the vertical tubes, a fluid distribution plate disposed over the tube sheet having converging surfaces forming openings conically tapered to converge downwardly towards the tops of each of the vertical tubes, with the upwardly diverging surfaces of each opening merging with the diverging surfaces of fluid entrance walls of adjacent conical openings to provide sharp entrance wall terminals, a soot blower rotatably mounted within the chamber above the fluid distribution plate, saidblower comprising a water cooled fluid feed pipe arranged to rotate in the axial center of the nest of tubes above the fluid distribution plate, and a Water cooled blast rack having a fluid discharge pipe extending radially from the feed pipe and rotatable therewith over the merging entrance wall terminals of said fluid distribution plate, said discharge pipe having downwardly directed nozzles in position thereon to discharge fluid into the conical openings above the nest of tubes during rotation of the blast rack.
2. Apparatus as claimed in claim 1, and which includes a motor drive for the blast rack with a control means operatively connected with the drive motor to connect and disconnect the drive motor automatically at regular time intervals.
References (liter! in the file of this patent UNITED STATES PATENTS 987,450 Eichelberger et al. Mar. 21, 1911 1,060,923 Ma Gee May 6, 1913 1,416,552 Garland May 16, 1922 1,978,555 Snow Oct. 30, 1934