US1516341A - jacobus - Google Patents

Description

METHOD OF AND APPARATUS FOR PROTECTING BOILER ECONOMIZERS FROM EXTERIOR CORROSION Original F'lled July 13 1918 2 Sheets-Sheet 1 A4 ATTORNEYS.

Nov. 18, 1924- 1,516,341

' D. S: JACOBUS METHOD OF AND APPARATUS FOR PROTECTING BOILER ECONOMIZERS FROM EXTERIOR "CORROSION Original Flled July 13 1918 2 Sheets-Sheet 2 NTOR.

//M'A TTORNEYS.

Patented Nov. 18, 1924.

UNITED STATES PATENT OFFICE.

DAVID S. JACOBUS, O'F JERSEY CITY, NEW JERSEY, ASSIGNOR TO THE BABCOCK & WIL- COX COMPANY, OF BAYONNE, NEW' JERSEY, A. CORPORATION OF NEW JERSEY.

METHOD OF AND APPARATUS FOR- PROTECTING BOILER ECONOLIIZERS FROM EXTERIOR CORROSION.

Application filed July 13, 1918, Serial No. 244,685.

T all whom it may, concern:

Be it known that I, DAVID S. Jacosos, a citizen of the United States, residing at J er sey City, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in Methods of and Apparatus for Protecting Boiler Economizers from Exterior Corrosion, of which the following is a specification.

The purpose of the present invention is to prevent corrosion on the exterior surfaces of economizers for boilers in cases where there is sweating on the exterior surfaces of the tubes ordinarily employed in the construction of such economizer, but I contemplate the use of my improvements in any field for which they are adapted by their nature.

An important object of my invention is to provide for the application of oil, as phaltum, pitch or the like material for preventing corrosion, to the tubes subjected to the sweating action, the protective material being fed at intervals or continuously along with the gases so as to cause it to spread over the surfaces, this method being particularly applicable where the gases are washed with water'hefore they are passed to the section of the economizer which is to be treated with the protective material.

Another important object of my invention is to provide means for applying uniformly in the desired quantities the protective material, such means serving also to remove any excess of the material or other accretions from the economizer tubes and I provide also for reclaiming any excess of the protective material fed to the economizer.

The'invention will be understood by reference to the accompanying drawings in which Figure 1 is a diagrammatic side elevation partly in section of a steam boiler plant embodying my invention; Fig. 2 a rear view of the high pressure stage of the economizer of Fig. 1; Fig. 3 is a fragmentary view in side elevation partly in section, upon an enlarged scale, of a portion of one group of the economizer tubes provided with oil-fed wipers; Fig. t is a view in transverse, horizontal section of one of the economizer tubes and wipers taken on the line ar -m in Fig. 3; Fig. 5 is a fragmentarv, detailed view upon a still larger scale of a portion of the wiper shown in Fig. 3;

Renewed April 12, 1924.

Fig. 6 is a diagrammatic view in elevation, partly in section of a modified form of boiler plant illustrating a modification of my invention. Similar reference numerals indicate similar parts in the several views.

My method may be carried out in connection with any suitable boiler plant, such as that illustrated and described in my application Serial No. 876,012, of which a description follows.

Referring to Figs. 1, 2 and 3, the numeral 1 designates a boiler of standard desi n having a longitudinal steam and water drum 2, and fired with a chain grate stoker 3, the waste gases from the boiler escaping through a flue in which the. economizer and spraying devices are located. For the purpose of describing one method of practising the invention I have shown a two-stage economizer with means for eliminating the air from the ater before it is delivered to the high pressure stage. The latter is designated generally by the letter A and is shown as located in a vertical flue 4, and as subjected to the hottest gases. The low pressure stage is designated generally by the letter B and is shown as located in a horizontal fine 5, and as subjected to the coldest gases. The gases are made to flow in a downward direction over the tubes of the high pressure stage, and the flow of water through said stage is, in general, in the reverse direction of the fiow of the gases. The high pressure stage of the economizer is shown in Fig. 2 as consisting of a series of rows of tubes 6 expanded into horizontal boxes or headers 7, said tubes having a slight inclination upward in the direction of the flow of the water. The tubes and boxes are preferably of wrought iron or wrought steel to withstand the high boiler pressure to which this stage of the economizer is subjected.

The low pressure stage is shown as consisting of four separated banks or groups 8, 9, 10 and 11, each of four sections, preferably of cast iron tubes fitted into cast iron horizontal boxes or headers. The spaces between the banks provide :lor access to the tubes through doors 12. Beneath each of these banks is a pit 13 for collecting steam condensed from the gases, or the oil which may be used for coating the outside of the tubes. Vipers 102 are shown on the tubes lUO lit

of the low pressure stage of the eeonoinizer for applying the protective coating thereto. The banks of the low pressure stage are so connected that the feed water entering through pipe 15 is distrilnited through the lower connected headers of bank ll and escapes from said bank through the upper headers thereof to the upper header of the right hand section or row of tubes oi bank 10; thence down said section to the lower header thereof from which it is distributed through the remaining lower headers of bank 10, thence upward through the other sections of bank 10 to the corresponding upper headers, and thence in a similar man ner through the sections of banks 5) and 8, finally leaving the low pressure stagethrough the pipe 16 leading to the tank 1?. It is to be understood of course that 1 do not limit myself to this exact connection of the several banks of the low pressure stage. In tank 17 are preferably perforated plates over which the water is made to lie w, and by which it is broken up, to facilitate the disengagen'i-ent and escape of air and es from the water, such disengagement her g assisted by heating the water in the low pressure stage of the cconomizer, and, if desired, by maintaining a partial vacuum in the tank by any suitable means; such as the dry vacuum pump 50; or the air and gases are permitted to escape through a relief valve 18. From the tank 17 the water is conducted by a pipe 19, to a feed pump 20 which forces it through a pipe 21 to the lower part of the high pressure stage oi the economizer. The water enters the lowermost header I and flows from side to side, through successive rows of tubes as indicated by the arrows in Fig. :2, and is delivered from the high pressure stage, througl'l pipe :52, into the steam and water drum 'lhis flow of the water through the high pressure stage of the economizer provides for a positive circulation, and the passage through tubes all of which are inclined upward with reference to the direction of flow of the water. and, in general in the reverse direction of the flow of the gases.

It is well-known that the rate of heat transfer from steam or liquids to a cooler surface, such as a tube wall, is much higher than the rate of transfer from gases at the same ten'iperature to the same cooler surface, and this principle is utilized by me in the operation of a steam boiler econom izer. In the arrangement shown in Fig. 1 I introduce water, or steam, or both t the gases between the high and low prr stages of the economizer, one means for such purpose being a series of perforated pip-es 2&1 connected to boxes located in the flue -l below the high pressure stage A of the eeonomizer. As shown, the wall *l of the line 4 stops short of the bottom of the flue so that the gases will flow through the passage below the wall at, and up aid to the opening into fine 5, and, if desired, a second series of perforated pipes 25 may be placed at the opening into flue The water or steam is delivered to the pipes and 25 by any suitable means. The water may be supplied to the well 26 at the bottom of the flue -l by a pipe 27 and pumped from the well by a pump through valved pipes 239 and 30 to the perforated pipes 23 and 25 from which it escapes in line streams or snray. Any suitable means other than perforated pipes may be used for spraying the water. The water in the well 26 is maintained at a lower lever than that in the pits 13 under banks of tubes of the low pressure stage of the economizer, and the water which collects in the pits 1&3 flows from one to the other through pipe connections 2:31,, passing through the partition walls. These connections are water-sealed to prevent the flue gases being drawn through them. The water which collects in the pit beneath the bank 8 of the low pressure sta 'e flows through a pipe Z132 to the well it, the lower end of pip-e Z523 being water-sealed as shown. ll'hen the water becomes too impure for use it may be drawn oil through a pipe 33 and fresh water supplied to the well 26. the water is circulated over and over again, a reagent to neutralize the acid fumes absorbed by the water may be added. lnstead of circulating the water, the plant may be operated by having a continuous supply of fresh water through pipes 29 and 30, and a continuous withdrawal through pipe 23;} with a sufficient supply in the well to maintain a water seal for the pipe 32.

Doors :26 may be provided in the wall of flue l through which access may be had to the well 26 for the purpose of washing out the sediment through pipe 33, or the sediment may be shoveled out through the doors.

When the water is sprayed into the gases, as above described, the water will partly evaporated and will reduce the temperature of the gases, as a limit, to approximately 212 IR, and this willv produce a coi'isiderable volume of steam which will be condensed as the gases pass over the low pressure stage of the economizer. This cooler stage of the economizer will be more active in absorbing the heat from the steam and moist gases than the same stage would be in absorbing heat from relatively dry gases.

As above stated, steam alone, or steam and water, may be used for i'noisten ng and washing the gases. In plants where the main steam motors are run non-condensing, there is a surplus of exhaust steam, and this exhaust steam could be used in place of water. Steam would. give additional heat to the eeonomizer and would serve to throw down the Cinders.

When i In addition to the advantage of an increased rate of heat transfer due to the addition of moisture to the gases, there is a further ad *antage in that the means described provide for the removal of soot, cinders and tar from the gases. In certain plants there is much trouble with the deposition of tar from the furnace gases on the coolesttubes of the economizer. This tar carries with it soot from the gases, the whole forming a pasty mass wh ch cannot be effectively scraped from the tubes and which collects at the lower ends of the tubes and above the lowermost headers. By using a water spray or steam, in the manner described, the greater part of the tar and the soot will be -arried down and deposited in the well 26.

Any suitable means may be utilized to carry out my process for the application of protective material to the exterior of the economizer tubes of the banks 8, 9, 10 and 11, and as one convenient form of device for this purpose I have shown each bank of tubes as having spreadingdevices somewhat similar in arrangement and operation to the scrapers illustrated in my application, Serial No. 876,012, these Spreaders being preferably made in three parts in the same way as the scrapers used in commercial forms of cast iron economizers. The part designated by the reference numeral consists of a skeleton frame or sleeve of which one may be provided for each of the economizer tubes 101 to be provided with protective material, these sleeves being operated by any suitable means, such as a carriage 102 for each bank of tubes, the carriages on adjacent banks being connected preferably in balanced relation by flexible devices 103 such as chains passing upward over pulleys 101 which may be utilized to operate the carriages 102, an actuating shaft 105, actuated by suitable means, not shown, being illustrated as the main actuating member. lVhen the shaft 105 is operated in the direction of the arrow 106, all the pulleys 104 are turned to lift one of the pairs of carriages, allowing the other member of each pair to descend, and reversal of the shaft raises the last mentioned members of each pair, and permits the others to descend, the oil, p tch or other protective material being supplied through pipes 107 mounted above the frames 100 and having perforations through which the protective material is delivered, and each frame preferably having means such as the leather insets 108 to spread the protective mater al over the surface of its pipe 101. All of the pipes 107 may be fed from a common source as by a pipe 107 having a valve and connecting the ends of all of the pipes 107 with a supply of protective material, such as a tank or the like.

Any excess of oil will descend int the its 13 and pass over through pipes 31, and 32 into the well 26 from which means to reclaim the oil may be provided, a convenient form of such means being shown at 13 which designates a drain pipe located ata height suitable to receive the oil without the water therebcncath. The pipe 131 may conveniently be provided with a valve by which the oil may be drawn off from time to time into a suitable tank as it accumulates in the well 26.

In the design shown in Fig. 6, I have illustrated modified apparatus for carrying out my protective process in connection with a boiler plant comprising a bank of generating tubes 200, which with the furnace 201, superheatcr 202 and. steam and water drum 203, may he, and are shown as being, of wellknown structure and arrange ment, so that detailed description thereof is not necessary.

From this boiler. the gases pass upward through a fine 204 in which I have shown a bank of tubes 205 constitut'ng a vertical economizer to which the water is introduced through pipe 206 by means of pump 207 and passes to the steam and water drum 203 through pipe 208.

The gases on passing from the vertical cconornizer enter a chamber 209 through which water is sprayed, being introduced thereto through a pipe 210, and from this washing chamber the water may flow to a settling tank and means for re-pumping, not shown. From the chamber 209 the washed gases pass over to an extension chamber 211 in which are installed the horizontally extending tubes of an economizer 212, this economizer being preferably of substantially the s'ame type and structure as that illustrated and described with reference to Figure 2.

In accordance with my invention, I provide for the application to the outer surfaces of the tubes in economizer 212 of a protective material, which may consist of oil introduced through a pipe 213 at high pressure through a spray nozzle 21 1- which applics it in atomized condition, the oil be ing preferably heated to secure a better atomization.

The gases after passing through the economizer 212 flow through an upwardly incl'ned conduit 215 of approximately the full width of economizer 212 which brings them together through a funnel-shaped connection 210 into a fan 217 driven by a motor 218 to create a forced draft in the stack 219.

The excess of oil may be collected as indicated at 220 at the base of the extension containing economizer 212, and suitable means, such as the pet-cock 221 may be provided for drawing off the oil.

lVhat- I claim and desire to secure by Letters Patent of the United States is 1. The method of protecting the exterior o'l a boiler econoiniiicr from corrosion, "which consis' l's in passing hot gas s over the exterior of the economist- 1" and Water through the interior thereof and applying a fluid-pr tectire naterizil to the exterior of the economiiger while the gases and Water are i on i ng.

2. The method oi protecting the exterior of a boiler economizer tron'i corrosion which consists in n ssino' hot over the exterior of the eco ominer and Water through the int-c ll. and appl ing substantially continue; a hind-protective initerial to tl e a ii'QIlOi the econ. nicer While the gases and \vare flowing.

Ti a. boiler, an econoniisscr hating tubes,

a line siirronnding s d tubes and ar lapted to condnctdiot g scs over the exterior thereof, and means Within the line to apply a protective coating to the exterior of the tubes While the hot gases are flowing over the. tubes.

4. in a boiler an tubes, 1:. line surrounding sai adapted to conduct hot gases over the ere terior thereof, and m inns within the time to spreac thiid-protectire material upon the exterior snrjlaces of toe tnbes \vl'iile the hot are dmvinp; over the tubes.

5. in a boiler, an economizcr having vertical tubes arranged in banks or stacks, a line to concoct hot gases over the exterior of the tubes, svreadcr devices to apply protectiv n iterial at a single operation to the tubes oi one of said stacks and means e3:- terior oi the line to operate said devices.

economizcr having verin a ooiler an ticsl tnl in banks or 'ac eronomizer having? d tribes and W arrange as, a tine to conduct hot over the exterior of tniiics spreader devices to apply protective males-Isl at a single operation to the tubes of one of said stack, means to connect in balanced relation the spreader devices upon adjacent stacks and means exterior of the tine to operate said devices.

7. A spreader device for applying protective material to tubes in boilers of the class described, said device con'iprising a frame having spreading; means, a supply pipe for the delivery oi? protective material to said spreading device, a carriage to operate a plurality of. said frames, and means exterior of the boiler setting to operate said carriages.

8. The combination with a boiler having an economizer, of means to apply protective material to the tubes thereof and means to collect the excess of protective material and reclaim it.

9. The combination in a boiler having an economizcr and means to spray the gases passing tln'ongh said economizer, of means to apply protective material to the tubes of a portion of said economizer, and means to collect and reclaim separately the fluids used in spraying and protection. respec tively.

10. The combination in a boiler having; an econoinizer and means to spray the .zes passing' through said QCODOlDlZQIF, oi means to apply protective material to the tubes of i a portion of said econoinizer, a tail: and connections thereto, adapted to collect in said tank the surplus spraying and protective fluids, and means to collect and reclaim separately the fluids in said tanlc.

In testimony whereof I have hereunto signed my name in the presence oi? two subscribing Witnesses.

DAVID 55. JACOBUS. llitnesses EDITH CAMP, JOHN A. ll DIXON.

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