US1313991A - And william a - Google Patents

Description

D. S. JACOBUS AND W. A. JONES.

STEAM BOILER ECONOMIZER.

APPLICAHON FILiD DEC-[8 19.

1,313,991. Patented Aug. 26, 1919.

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UNITED STATES PATENT OFFICE.

DAVID S. JACOBUS, 0F JERSEY CITY, NEW JERSEY, AND WILLIAM A. J ONES, OF WEST NEW BRIGHTON, NEW YORK, ASSIGNORS TO THE BABCOCK & WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A. CORPORATION OF NEW JERSEY.

STEAM-BOILER ECONOMIZER.

Specification of Letters Patent.

Patented Aug. 26, 1919.

Application filed December 8, 1914. Serial No. 876,015.

To all whom it may concern.

Be it known that we, DAVID S. Jaoonus, a citizen of the United States, residing in Jersey City, in the county of Hudson and State of New Jersey, and WILLIAM A. JONES, a citizen of the United States, residing at West New Brighton, Staten Island, in the county of Richmond and State of New York, have invented certain new and useful Improvements in Steam-Boiler Economizers, of which the following is a specification.

In an application Serial No. 784,315, filed August 12, 1913, by David S. Jacobus, is described a system by which liability of corrosion of an economizer is prevented or minimized by first heating the feed water, then withdrawing it from the heating apparatus and permitting the greater part of the air or gases to escape before this water is fed to the economizer or a part thereof. In that application the feed Water is heated by passing it through the low pressure stage of a plural stage economizer and then delivered to a tank in which the greater part of the air or gases is permitted to escape. From this tank the water is forced through the high pressure stage of the economizer against the boiler pressure, the high pressure stage being subjected to the hottest gases. To meet the requirements of modern power plant practice of large size boiler units and high over-loads, a wrought iron'or wrou ht steel construction was used for the high pressure stage of the economizer, such use being permltted because of the ractical elimination of the air and gases rom the water before it is delivered to the high pressure stage. The present invention enables us to retain the use of cast iron for the low pressure stage of the economizer, and thereby the advantage of the less liability of cast iron, over wrought iron or steel, to corrosion.

The present invention relates to a special construction of a two-stage economizer adapted for use in the system described in the saidqa plication Serial No. 784,315, and will be un erstood by reference to the accompanying drawings in which Figure 1 is a side view, partly in section of one form of economizer embodying our invention; Fig. 2 a top view, partly in section of the economizer of Fig. 1 with part of the coverin -rcmoved, and showing also diagrammatn cally, a tank for the removal of air and gases from the water after it passes through the low pressure stage; Fig. 3 a part longitudinal section on the plane of the line 3-4? of Fig. 5 through the low pressure stage of the economizer; Fig. 4 a transverse section of the same, partly broken away on the plane of the line 44 of Fig. 5; Fig. 5 a top view of the low pressure stage, showing the direction of the flow of the feed water through the headers and tubes; Fig. (in transverse section through one of the upper headers of Fig. 5; Fig. 7 a top view of a portion of one of the lower headers of the high pressure stage of the economizer; Fig. 8 a transverse section on the plane of the line 88 of Fig. 7 Fig. 9 a horizontal section on the plane of the line 99 of Fig. 10; and Fi 10 an end view of the header and tubes 0 Fig. 8. Similar reference numerals indicate similar parts in the several views.

In the drawings the letter A designates generally the low pressure stage, and B the high pressure stage of the economizer which, in practice, will be located in the outlet flue of a steam boiler. The flow of the gases is indicated by the arrow on in Fig. 2, the high pressure stage being subjected to the hottest gases and the low pressure stage to the coldest gases. The flow of the water through the economizer is, in general, in the reverse direction of the flow of the gases. The low pressure stage is arranged in separated banks of vertical tubes, these banks being made up of groups of sections comprising upper and lower headers and connecting tubes. As shown, there are three banks or oups of sections, the tubes and sections of the first bank being numbered in Fig. 3, 1 to 8 inclusive, those of the second, 9 to 16 inclusive, and those of the third section 17 to 24 inclusive. The tubes are arranged in rows, each row being connected to upper and lower headers, as hereinafter explained, and the tubes of one row staggered with respect to those of an adjoining row, in order to prevent laneing of the gases and to expose all of the tube surfaces to the impinging gases. The feed water from the hot well, or any other source, enters the low pressure stage of the economizer through the inlet 25 and is delivered to a inanifold header 26 (Figs. 2 and 5), and from the latter the water is distributed to the eight lower headers 27 of the first bank or group of sections, to which the lower ends oi the tubes are connected. The water then flows upward from the headers 27 through the tubes 1 to 8 inclusive to the upper headers 28 and from the latter through'return bends 29 (Fig. 5) into a manifold header 30. The header 30 extends midway of the second bank or group of sections of the low pressure stage, and the water from the manifold header 30 is delivered through return bends 31 into four upper headers 32, the water passing from said headers 32 downward through the four rows of tubes 9, 10, 11 and 12 to the lower headers 33 (Fig. 3) and from said latter headers to the lower manifold header 34 (Fig. 5) from which it is distributed to the four lower headers 35 (Fig. 3) of the second bank or group of sections, and from thence upward through the tubes 13, 14, 15 and 16 to upper headers 36. From the headers 36 the water flows through return bends 37 (Fig. 5) to a manifold header 38 from which header it is delivered through four return bends 39 to four upper headers 40 of the third bank or group of sections of the economizer, thence downward through tubes 17, 18, 19 and 20 of the third bank and is discharged into headers 41 (Fig. 3) and thence to'm'anifold header 42 (Fig. 5 from which it is distributed to four lower headers 43 from which it flows upward through tubes 21, 22, 23 and 24 to upper headers 44, through return bends 45 to manifold header 46 from which it is discharged through pipe 47 It is to be understood, of course, that the invention is not limited to the exact number of sections in a group, or the exact number of sections or groups of sections or method of circulation shown.

The spaces between the banks or groups of sections are wide enough for a workman to enter through access doors 48 (Fig. 1), and the width of each band is such that all of the tubes are accessible. Doors 48' are provided at the sides and near the lowermost ends of the tubes. The doors 48 and 48 are preferably of cast iron, asbestos packed and lined, and fitted with cast iron frames. Beneath each of the banks or groups of sections are hoppers 49 for collecting soot deposited from the gases and that removed from the exterior of the tubes by scrapers 50 hung by chains over wheels 51. The latter are geared to a shaft 52 adapted to be rotated in both directions to raise and lower the scrapers along the tubes. When the doors 48 are open the lower ends of the tubes of the low pressure stage of the economizer are exposed throughout the entire length of the low pressure stage, giving accessibility for cleaning the lower ends of the tubes from the sides of the economizer by means of a scraper or other tool. This is an es ecially desirable feature as with water fe to the economizcr directly from the hot well at at temperature of say 80 F. there will be condensation or sweating on the outside of some of the tubes of the low pressure stage, and this causes the dust and soot which falls to the lower ends of the tubes to become cemented to the tubes and to the lowermost headers. The cleaning doors give ready access, without cooling down the BCODOII'llZOI, for removing this material which otherwise would bridge over between. the headers and eventually interfere with the operation 01 the scrapers and the eli'iciency of the apparatus.

The doors 48 and the spaces between the banks permit a workman to enter between the banks of tubes and provide for access to the full length of the tubes for coating the tubes with paint, or other material, to prevent or minimize external corrosion. Even when the scrapers 50 are usedthe low pressure stage should be arranged for access as a pasty material may cling to the lower ends of the tubes and above the lower headers, and by providing access between the banks and at the ends of the sections, and by making the banks of such a nunrber of sections that all of the tubes can be reached, this material may be removed by hand when the boiler is shut down. Should any of the fumes or vapor. condensed from the gases drop from the lowermost headers, it will fall into the hoppers 49. The moisture in the soot and dust which falls into the hoppers 49 will be evaporated under ordinary running-conditions as the gases which circulate slowly through the hoppers are hotter than the surfaces of the economizer tubes. The soot and dust are removed through suction discharge pipes 53 and 54.

The three manifold headers 26, 34 and 42, shown in Figs. 2 and 5, have connections 55, 56 and 57 respectively to a common blow-off main 58, shown in Fig. 3.

in Fig. 6 is shown the usual construction employed in cast iron economizers for con necting the tubes with the headers. The headers 28, 32, 36, 40 and 44 are similar in construction. As shown, they are provided with handhole plates 64 which. are drawn to their seats by bolts 65 and brace 66.

From the low pressure stage of the economizer the water flows throu h pipe 47 to a tank or heater 59 (see Fig. 2 in which tank the air and non-condensable gases are permitted to escape into the atmosphere through a relief valve or vent pipe 59', or are withdrawn through a pipe 60 connected to a dry vacuum pump to maintain the pressure above the water in the tank at less than atmpspheric pressure. Any other suitable means may be employed for maintaining a partial vacuum in the tank 59. The tank 59 is provided with a blow ofi connection 59 for removing any mud or deposit. A filter 59 is placed in the tank 59. From said tank the water is delivered through a pipe 61 to a pump 62, and by the latter forced through pipe 63 into and through the high pressure stage of the cconomizer against the boiler pressure.

The high pressure stage of the economizer, as shown. consists of ten similar sections, each section consisting of a lower header or box 67 and an upper header or box 68, connected by two rows of vertical tubes 69 arranged in staggered relation, as shown more particularly in Fig. 7. As shown in Figs. 1 and 2 each upper header is connected to the lower header of the next section by a series of inclined tubes 70 so that the water from pump 62 enters the high pressure sta e throu h the left-hand lower header 6 flows upward through the tubes 69 of that section to the upper header 68 and thence downward through the inclined tubes 70 between the first and second sections to the lower header 6'? of the second section. Thence through the vertical tubes 69 of the second section to the upper header of that section, thence downward through the inclined tubes to the lower header of the third section and so on through all of the sections to the top outlet 71 from whence it is led to the boiler. As shown in the drawings (see Fig. 2) the inclined tubes connecting the upper header of one section to e lower header of the next succeeding section are fewer in number than the tubes in the vertical rows.

The circulation in the high ressure stage of the economizer is novel in that, the water enters the bottom of each section, passes upward through the tubes of that section, and then downward to the bottom of the next succeeding section. About every tenth tube is expanded into the upper box of one section and into the lower box of the next section forming the inclined downcomers 70 for conveying the water from one section to the next succeeding section. The advantage of this construction is that the water is maintained at a comparatively high and uniform velocity through the economizer, thus making it possible to Sweep away any bubbles of air or non-condensable gases whichmay collect on the inside of the tubes. This is accomplished by using a less numberpf downcomers for conveying the water from one section to another than there are vertical tubes through which the water flows upward. The dlS- lodgment of bubbles of air or non-condensable gases through the flow of the water is particularly effective with the arrangement described, as where the water is made to flow downward the velocity is high, in order that it shall overcome the tendency of the bubbles to rise through the water and provide an additional impetus to sweep them from the surface of the tubes and carry them downward alon with the water. Where the water rises t rough the tubes the buoyancy of the bubbles assists in releasing them from the surface of the tubes and it is not necessary to maintain as high a velocity as where the flow is downward. After the air or non-condensable gases reach the upper part of a section they are bled to the next section by vent connections 72 (Fig. 2) formed by connecting each uppermost box with one at its side by a pipe of relatively small diameter. These connec tions are attached to the ends of each upper box and are arranged so that any air or noncondensable gas which may be present will pass from box to box traversing the full length of each box in its passage from one end of the economizer to the other. In addition to the vent connection for passing the air or non-condensable ases from one box to another, each upper eader of the high pressure stage is provided with air valves 73 (Fig. 2) which can be opened to allow the air to escape in filling the economizer with water, or which may be opened when drawing water from the economlzer.

With the method of circulation described the water flows successively through each section and the temperature of the water is gradually increased from section to section from one end of the high pressure stage to the other; this leads to a maximum efficiency in the absorption of heat.

It may be further noted that the described arrangement avoids a stagnation in the flow of water in any of the tubes of the high pressure stage, as the water flows upward through a large number of tubes, and if any one of these tubes should become heated to a temperature higher than that of the other tubes of the same section, the water in the hotter tube would be less dense than that in the other tubes of the same section, and would offer less resistance to the upward flow of water, and, therefore, a reater uantity of water would immediate y flow t rough the hotter tube and this would cool the tube and restore the equilibrium of flow through the tubes of that particular section.

A relatively few tubes conduct the water downward from the upper header of one section to the lower header of the following section. If any one of the tubes 70, through which the water flows downward from a you section, should become heated above t e temperature of the other tubes, 70, of that section, the water in the hotter tube would become less dense and would ofler a greater resistance than the others to the downward flow of the water, which would at once tend to increase the temperature of the hotter tube still further. This tendency to localize the flow of water through one or more of the downcorner tubes is overcome by em loying a small number, which makesthe fr ctional resistance within the tubes relatively high, so that the increase in friction due to a slight increase in the quantity of water flowing through c e tube over another, is greater than the di-Eerence in resistance due to differences in the tempenature of the water, and thus the water is made to divide itself: properly among the ewncomer tu es.

Although we have described the how of the water up and down the tubes fromsec- ,tion ,to section in series, a small amount of h water i bypa s from one e i n t the next through the small pipe connections 72 used for conveying the air and non-condensable gases from one header box to the next. As already explained the vent connections are so arranged that the air and gases enter one end of each u per box and leave at the other end of te same box, traveling the length of the box. This is advantageous in preventing a direct short circuiting of the water w ich might take place by having ll of the vent connections on one side of the economizer, and itavoids the possibility of the air and non-condensable g es collecting in dead spaces in the boxes. ny water which fiO-Ws through the vent connections 72 along wit the gases from one box to the next ,rningles with the water in that box before en 'ering the succeeding vent connection an there is no opportunity for the cooler water from the inlet endof the economizer to directly into the hotter water at the exit end of the economizer.

he high pressure stage is provided, as shown in Fig. 1, with individual blow-oil valves 7 and connections 78 for each lowermost header. Thisis especially advantageous as by blowing each hea er separately 2. hi h .velocity can be secure through the hea ers which makes it possible to carry away any sediment much nore eificiently than where there isa single blow-,oii fora ll mber of headers. We also provide openings 81 in the top of the casin for the high pressure stage'xsee 1 an 2) for the introduction of an air or steam lance between the boxes for dusting the outside of the tubes;

In addition to tie cross passa es for a workman to enter between the anks or groups .of sections of t e low pressure stage, there is a similar cross passage between t 1e low pressure stage and the high pressure stage, these cross passages afiording access to the tubes as before described.

In F 1 and 3 we have shown vertical diaphragms 79 in the soot hoppers 49 to prevent short circuiting of the ases. underneath the low pressure stage, an transverse channels 80 forming flooring parti lly fillin in th spaces between groups of eaders o in this Way the low pressure stage, and between the low pressure stage and the high pressure stage. These channels are shown as narrower than the spaces in which they are placed so that there is an opening at each side of each channel to permit dust to fall down into the ho pers.

v n addition ,to the foregoing features of construction we have shown more articularly in Figs. 7 to 1.0 the means by w 'ch the tubes of the high pressure stage may; be expanded into the upper and lower eaders. As there shown, opposite each tube in the square headers or boxes are inside hand-hole fittings 74 to per it examination cleaning and expanding to tubes, The hand-hole openings 7 5 are of less diameter than the tube holes 76, and the tubes cannot be passed through the openings opposite them in the boxes. The tubes are removed and replaced, when desired, by passing them downward through the s aces between the boxes, clearly indicated in fig. 2, and slipping one end of the tube through this hole in one of the boxes, and then moving t e tube in the reverse direction through the hole in the opposite box. Thi method ,of introducing the tubes has an advantage, in that, as much hea room is not required or removing and replacing tubes as in a construction w ere they must be drawn upward through :ho es in the headers or boxes which come opposite is e tubes. The handhole fittings 74 are circular and are made tight by means of gaskets, and by uneans of a cross piece and nut which come outside of the boxes. They are passed inside the boxes through the oval hand-holes 7 6 at the end of the boxes.

It will be understood that we intend to cover the construction and arrangement shown in each stage, whether such construction is used by itself in a single stage economizer or in a multiple stage economizer.

hat we esire to secure by Letters Patent of the United States is 1. steam boiler economizer comprising apluralcity of sections each section having a sing e upper and a single lower cross box connected by venti ly extending upflow qn mie lbfl .ilhpe ibd ii a i g d pending do wnflow ,tubes spaced along the ngt 0 t. e b x nd n cting i t lower box o the next sectio' the cross sectional area of these do wn ow tubes being less than the cross sectlonal area of the up How tubes to the upper box, and the down glow tubes forming part of the heating sur- 2. A steam boiler economizer comprising a p ura ty of s as each s ion ha in a sdhgle upper an a single lower cross box e e ed t v t e l extend g r o Economizer tube aeh upper b x haying pending downflow tulbes spaced along t e g h o he x and ee ee ing i to t lower box of the next section, the cross sectional area of these down flow tubes being less than the cross sectional area of the up flow tubes to the upper box, the down flow tubes forming part of the heating surface, all of the tubes of each section, including the down flow tubes from the upper box to the lower box of the next section, being staggered relatively to each other.

3. A steam boiler economizer composed of a series of sections each section having a single upper box and a single lower box connected by vertically extendin tubes, each upper header of each section iaving a bypass connection leading to the upper header of the next section for conveying air or noncondensabie gas through the successive upper headers.

4. A steam boiler economizer composed of a series of sections each section having a single upper box and a single lower box connected by vertically extending tubes, each upper header of each section having a bypass connection leading to the upper header of the next section for conveying air or noncondensable gas through the successive upper headers, and each of the by-pass connections having an air escape valve.

5. A steam boiler economizer composed of a series of sections each section having a single upper box and a single lower box connected by vertically extending tubes, each upper header of each section having a bypass connection leading to the upper header of the next section for conveying air or noncondensalble gas through the successive upper headers, said icy-pass connections being arranged to compel the air and gas to trav erse the entire length of each of the upper headers in their passage from one end of the economizer to the other.

In testimony whereof we have hereunto signed our names in the presence of two subscribing witnesses.

DAVID S. J ACOBUS. WILLIAM A. JONES.

Witnesses:

EDITH CAMP, JOHN A. W. DIXON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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