US1474162A

US1474162A - pratt

Info

Publication number: US1474162A
Authority: US
Publication date: 1923-11-13
Anticipated expiration: 1940-11-13

Description

Nov. 13, 1923. 1,474,162 v A. D.- PRATT WATER TUBE BOILER Filed Oct- 16, 1919 2 Sheets-Sheet 1 7! Q INVENTOR.

flrfur' fi. fraii BY fEQI/L ATTORNEYS.

Nov. 13,1923.

A. D. PRATT WATER TUBE BOILER Filed Oct. 16, 1919 2 Sheets-Sheet 2 IN V EN TOR.

A TTORNEYS.

Patented. Nov. 13, 1923.

UNITED STATES 1,474,152 PATENT OFFICE.

ARTHUR D. PRATT, OF NEW YORK, N. Y., ASSTG'NOR TO THE BABCOCK & WILCOX COM- PA'NY, OF BAYONNE, NEW JERSEY, A. CORPORATION OF NEW JERSEY.

WATER-TUBE BOILER.

Application filed October 16, 1919. Serial No. 330,946.

T all whom it may concern Be it known that I, ARTHUR D. PRATT, a citizen of the United States, residingin the city of New York, borough of Manhattan, county and State of New York, have invented certain new and useful Improvements in Wate-r-Tube Boilers, of which the followin is a specification.

ly invention relates to a water tube boiler especially designed for use where there are large quantities of dust in the gases, and particularly an arrangement by which the battles and tubes in such a boiler may be relieved of the accumulation of dust which will collect thereon. In the drawings, Figure 1 is a side elevation partly in section of a boiler embodying one form of my invention; Fig. 2 is a side elevation, of the exterior of the furnace illustrated in Fig. 1, with some of the side wall broken away; Fig. 3is a section on the line 3-3 of Fig. 2; Fig. f is a side view, partly in section, of the movable battles; and Fig. 5 is a side view of the movable bafiles. Similar reference numerals indicate similarparts in the several views.

The boiler illustrated comprises two transverse steam and water drums 1 and 2 and a transverse mud drum 3, set parallel and connected by banks of tubes 4 and 5. The upper drums are connected by steam circulators 6 and Water circulators 7 The latter support tiling which 'forms a roof over the cross passages from the uptake to the downtake and prevents the gases from striking the drums above the water line. Each bank is shown as having five rows of tubes, the upper ends of which are straight and are expanded into a stepped tube sheet, and the lower ends curved to properly enter a circular mud drum. Two additional rows of vertical tubes 8 and 9 connect the mud drum with the upper drums, these two rows forming a central bank. A bafile wall 10 is built in the space between the rows of tubes Sand 9, the tubes forming a support for the wall which extends upwardly from the mud drum to such height as to leave ample space 7 for the products of' combustion to travel from the front to the rear pass. The wall 10 is accessible for repairs through the doors 20, there being ample room for a man to work between the banks of tubes.

-The vertical battle wall 10 is located centrally between the main banks of tubes. Projecting from said baffle wall to the main banks of tubes are cross baflles 11, preferably of cast iron. A similar baffle 12 is located between the bank of tubes 5 and the rear wall of the setting. As one means by form which I have chosen for purposes of illustration, the shafts 121 are provided with weights 122-arranged to hold-the baflle normally in operative position.

Suitable dusting doors 142 are provided through which an air or steam lance may be introduced for blowing the accumulated dust from the surfaces of the tubes and also from the surface of the mud drum. Hoppers 15 may be placed under the setting to receive the deposits. Any dust deposited upon the baffles 11 and 12 may be readily discharged therefrom by turning or shifting the battles, and the accumulation upon the tubes and the mud drum removed by an air or steam lance.

The boiler may be fired by any suitable furnaces, indicated at 16. The gases enter the lower part of the front bank of tubes 4%, flow in a general upward direction over said tubes thence across above the baffle wall 10 and in a general downward direction over the tubes of bank, 5. The battles l1 and 12 causethe gases, in their general flow, to cross and recross the banks of tubes as indicated by the arrows. The gases finally escape. through the outlet 17. A seal 18 between the wall 19 and the lower drum, prevents short circuiting of the gases.

The main steam outlet 21 is placed at the top and centre of the rear steam and water drum. A feed water connection 22 dis charges into a trough in the rear drum and rid' of at frequent intervals by rotating the cross baffles 11 and 12 and removing the accumulation from the surfaces of the tubes by an air or steam lance. Because of the large .tical and straight throughout a amount of dust in the gases, the tubes t and 5 will also become coated, so that it is necessary to provide some means by which this dust or deposit may be readily removed from them. To this end, I have provided. scrapers 23 on each bank of tubes together with means by which they may be moved along the tubes to remove the deposits. In order that these scrapers shall be mosteflective, I prefer to arrange the tubes as shown in Figure 1 withtheir upper ends straight and vertical so as to enable the scrapers to operate up to the point where the tubes enter the upper drums l and 2. To this end, I preferably provide a stepped tube sheet for the upper drums, though it is obvious that any other form of tube sheet which will permit the bank of tubes to enter the drum without curving't'he tubes, will answer my purposes.

As shown in Figure 1, the lower drum 8 is out of vertical alinement with the upper drums and by making the tubes 4 and 5 vergreater portion of their length, beginning at the up per drums and by curving the lower portions only in order to connect the tubes into the lower drum, I provide an arrangement by which the scrapers 23 may operate over the greater portion of the length of the tubes and, at the same time, by reason of the curvature at the bottom of the tubes, the dust removed by the scrapers 23 will fall away from the drum 3 into the hoppers 15.

The scrapers 28 may be of any suitable construction and, in the form illustrated, comprise cylindrical members to made in two or three parts surrounding each of the tubes, these cylindricalmembers havingprojections which engage between the plates of a frame 30 to cars 31 of which are attached chains passing over chain wheels 33, 3-5- and 35, the corresponding chain wheels on either side of the settin being connected by suitable shafts, and tie whole system of shafts and wheels being turned, in the form illustrated, through suitable gearing by a motor 37, r

As will be seen by an ins iiection of Figure 1, the two sets of scrapers counterbalance each other; that is to say. when one is at the top of the tubes, the other is at the bottom. Rotation of the shaft of the motor 37, first in one direction and then the other, will move the scrapers up and down the tubes to clean off the deposit and dust. In their upward travel, the scrapers move up to the upper drums l and 2.

The arrangement of the cylindrical members and the frame 30 supporting them is such as to permit the removal of any of the cylindrical members or the frame without disturbing the tubes with which they cooperate.

If desired, the scrapers 23 may be kept in continuous motion while the boiler is in operation. To this end, in" the form illustrated, one of the chains connected to the scrapers is provided with a pair of members 8'71 and 87 2, arranged to contact alternately with a switch lever 88. The switch serves to reverse the motor 37. By this means, the switch lever is moved and the motor reversed as each scraper alternately reaches the limit of its upward stroke. Any other form of scraper moving means may be used, such as hand-operated chains, or the switch 38 may be thrown by hand.

Preferably, the baffles 11 and 12 are made to extend closely to the tubes 5 and 6. Unless provision were made for it, this would prevent the passage of the scrapers To permit this, I arrange the scraper frames and the ba'tlles so that contact between the two will serve to tilt the ba-flle to permit the scrapers to pass, in the manner'shown in Fi 2. As soonas the scraper has passed, weight 122 will return the bafiie to normal position. 'lhe arrangement I have shown for this purpose is extremely simple, but obviously any suitable form of baflie operatin device may be used.

lvhlle I have illustrated my invention in connection with a steam boiler, it will be understood that many of its parts may be applied also to any other form of water heater such as the economizer portion of a boiler and it will be understood that the term boiler as used in the appended claims refers notonly to a boiler proper but also to the economizer portion of a boiler.

.lVhat I claim and desire to secure by Let-' ters Patent of the United States is 2- l. A boiler having part of its heating surface formed of vertically-extending straight tubes with laterally curved lowerportions, and scrapers permanently mounted upon the tubes and arranged to scrape the surfaces of their straight portions, the curvat'ure of the tubes being such as to permit the soot thus scraped off to drop away be tween the lower )arts of 'thetubes, and mov able baflies having a portion thereof -nor mally located. in the path of movement of the scrapers, and adapted to be contacted by the scrapers to be moved out of the path of the scrapers. 1 a

2. A water tube boiler having a set of permanently mounted scrapers engaging the straight portions of some of its water tubes, means to reciprocate the scrapers. and a baflle having a portion thereof in the path of the scrapers, said baffle being arranged to be moved by the motion of the scrapers to permit the scrapers to pass the baffle when the scrapers are moved in either direction.

3. A boiler having a vertical flue and a bank of tubes extending lengthwise of the tubes. a battle extending from thewall of the flue to the outermost of the tubes,

scrapers surrounding the outermost tubes and arranged to be moved up and down thereon, said bafi'le being arranged to be moved by the motion of the scrapers to permit the scrapers to pass the baffle when the scrapers are moved in either direction.

41.. A boiler having a vertical flue and a bank of tubes extending lengthwise of the tubes, a battle extending from the Wall of the flue to the outermost of the tubes, scrapers surrounding the outermost tubes and arranged to be moved up and down thereon,

said baffle being pivotally mounted and arranged to be held normally in operative position by gravity and to be moved out of 1 normal position by the scrapers.

ARTHUR D. PRATT.