US1904216A - Steam generator and superheater and operation thereof - Google Patents

Description

C. B. FORWARD April 18, 1933.

STEAM GENERATOR AND SUPERHEATER AND OPERATION THEREOF 4 Sheets-Sheet 1" Filed NOV. 2, 1922 w Wm M April 18, 1933. c. B. FORWARD 1,904,216

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April 18, 1933. c B, FORWARD STEAM GENERATOR AND SUPERHEATER AND OPERATION THEREOF Filed Nov. 2, 1922 4 Sheets-Sheet 3 LZfl ZED TIPE snow/tom 05.1"!) PWARP p i 1933. c. B. FORWARD STEAM GENERATOR AND SUPERHEATER AND OPERATION THEREOF 4 Sheets-Sheet 4 Filed NOV. 2, 1922 i 7 VENTOR CB. FORWARD. MM 5X im lulvu-i mm Patented Apr. 18, 1933 iirrs STATES CHAUNGEY B. FORWARD, F URBANAgOI-IIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

FORWARD PROCESS COMPANY, OF DOVER, DELAWARE, A. CORPORATION OF DELA- WARE STEAM GENERATOR Ann surnzarrnn'rnn AND OPERATION rnnnnor Application filed November 2, 1922. Serial No. 598,464.

My invention relates to an improvement in a steam generator and superheater and in the operation thereof, and in general my 7 object is to provide a simple and efiicient apparatus or boiler capable of producing and delivering steam at any desired pressure at normal temperature or superheated steam up to any desired temperature rapidly and continuously with a minimum amount of fuel. 'The apparatus is also constructed in a particular way to simplify its erection and installation; to reduce its cost of erection and operation; to permit long and'continued use thereof without replacements and repairs; to facilitate repairs and replacements when needed to determine the line or place of demarcation of the water and steam in operating the apparatus; to promote inspection .of and withdrawal of all sediments and accumulation from theapparatus; and to make the apparatus as a whole safe and dependable when operating under extremely high pressure; all substantially as hereinafter shown and described and more particularly pointed out in the claims.

In theannexed drawings, Fig. 1 is a front elevation and a vertical section of my improved apparatus on line 1-1 of Fig. 3. .Fig. 2 is a rear elevation of the apparatus, Fig. 3 is a vertical section on line 3-3 of Fig. 2, and Fig. 4 is a horizontal section on line 4-4 of Fig. 2. Fig. 5 is a plan viewof one of the short units of. the superheating coil. Figs; 6, 7 and 8 are horizontal sections on lines 6-6, 77, and 8-8, respectively, of Fig. 2 showing the different forms of coil units contained in the upper, intermediate and lower heating zones, respectively,2of the apparatus. The apparatus comprises a brick furnace 2 built in the form of a rectangular stack which is wider at its base than at its top to provide a relatively long vertical chamber 4 having a converging outlet end in open communication with a smaller vertical passage or flue 5. A front enlargement 6 at the base contains horizontal openings 7 end of chamber 4 against a curved deflecting surface 9.

Combustion chamber 4 is rectangularin cross section and extends upwardly on straight lines for a considerable distance be fore the side walls 33 converge and narrow the passage, and this combustion space contams a large number of tiers or rows of coilsof pipe 10 of small diameter arranged so closely together in staggered relation one above the other that the hot gases of coma bustion must pass upwardly in a circuitousmanner between the horizontal pipes and in passing each row or tier of pipes impinge and be deflected by the pipes in a row above until the converging part of the combustion space is reached where a series of headersQl and" pipe of smaller size are placedftier upon tier into the smaller vertical flue or passage 5. The pipe or tubing 10 is preferably either two, or two and one-half inches, in diameter internally, and in one sense this pipe is in the form of a single continuous coil from beginning to end where exposed to the gases'in the combustionchamber and this coil conveys a small round stream of water and the steam vproduced therefrom back 'and forth repeatedly through this chamber or heating zone.

Onthe other hand this coil or pipe is actually made of a multiple number of coils,*or

in other words, in sections embodying bends and turns making shorter coils, and further more, there are two groups of COll sections A and B, respectively, superposed or arranged at different elevations in the combustion chambers. These two groups of coils of pipe differ from each other in that the rows or tiers of pipe-in lower group A are relatively much fewer in number than in upper group B, and in that each row of pipe in the lower group A is made of short flat coil sections C having extended extremities 11 projecting horizontally and rearwardly outside of the rear wall of the furnace and connected together successively in the same row by flanged unions 12, whereas each row or tier of pipe in the upper group B consists of a single long flat coil or section of pipe extending horizontally without a joint the entire distance from one side wall 3 to the other side wall 3 of the furnace and housed entirely within the four walls thereof except at their straight and longer extremities 13 where projected through the vertical rear wall relatively near the meeting corner with side walls 3. The short coil sections C are bent into the form of a compact letter M or W, the middle branches 14 of each coil section being of slightly greater length than the narrow part of the combustion chamber 4: be-

tween the front and rear walls thereof. The connecting portions 15 between the legs and middle branches of each coil section C are rounded or semi-circular and rest upon or are embedded in the courses of brick forming the front and rear walls of the furnace, and the extremities 11 of the longer legs of each coil section C, except the end ones, are curved laterally to promote their union with the extremities ofthe coil sections corresponding therewith and placed next thereto in the same row or tier. Each end section C in each row has one straight extremity 17 projecting through the wall to permit a return bend connection 18 to be made with the corresponding straight extremity of the end section in the tier or row of section C immediately above or beneath it. The superposed sections C are not placed directly above one another but are staggered to bring the pipes of one opposite the spaces in the other and this arrangement also places the unions in staggered relation with ample working room therebetween outside of the rear wall of the furnace. The straight projecting extremities 17 of the end sections of each row are also thereby 01fset or staggered one above the other; which places the return bend 18 at an inclination and gives more room to make the coimection and to avoid a sharp bend in the return bend. The last coil section C in the bottom row of pipe in group A has a discharge connection 19 extending outside of the rear wall of the furnace, see Fig. 1. and the section at the opposite or right end of this bottom row is con-" nected by a return bend 18 with the last section in the row of pipe immediately above. Then the section at the left end of this second row of pipe connects by a return bend 18 with the end. section in the third row from the'bottom and thus from row to row the return bends connect the pipe in group A with alternating turns to build up a large coil com-' posed of smaller coil sections in the hottest zone of combustion in the furnace.

Each row or single long coil section b in group B is connected at its opposite extremities 12 by inclined return bends 18 in the same ways as the rows of pipe in group A, thereby building a long coil of a plural number of smaller coils.

Each section b is also staggered in respect to the next section above, and a single continuous flat coil of pipe without joints is used for each section b in group B because the temperature in the upper heating zone of the furnace is not so high nor severe as in the lower zone containing group A and because replacements are not as frequent or necessary as in the lower hotter zone. The short M or W sections C in group A permit repairs and replacements to be made conveniently and quickly with a minimum of expense and labor, and these short sections are preferably made of calorized pipe to withstand the extremely high temperature.

A third group D of circulating pipes is located in the upper flaring portion of the furnace and these connect with the first or highest coil section b in group B. The pipes 20 of group D are relatively much smaller in diameter than the pipes in groups A and B and comprise straight pipes which extend on parallel lines in very close formation from front to rear between short headers 21 which rest horizontally within the brick walls one upon the other in the flaring upper end of the chamber and also for a short distance upwardly in the mouth of the rectangular discharge flue 5.

Each header 21 is equal to or larger in diameter than the pipe or tubing 10 forming the continuous coil made by sections A and B, and to prevent an impedance in flow in the supply of water the opposite headers 21 are connected together by a plural number of pipes 20, the aggregate cross sectional area of which is equal to or greater than the head ers themselves. The headers 21 opposite each other in the same horizontal plane are also staggered in respect to each other and connected by the pipes 20 in such a manner that the flow of water will pass into one half of one header and then out of the other half through the remaining pipes 20 in that header into the opposite header where the water will in turn be discharged through the multiple number of pipes 20 across the heat passage into another header and so forth in a circuitous manner until the first coil section b in group B is reached. Group D being composed of short headers and a multiple of straight connecting pipes, the number of headers in each superposed row depends upon their location in the flaring passage and the smaller flue. and inasmuch as each row of headers is connected to the row of headers immediately below and above the several rows of headers and their connecting pipes these also become in a sense sections of the complete heating coil in the furnace. The end headers 22 at the rear of the furnace in each superposed row of headers. have tubular branches 23 projecting through the rear wall where return bends 24 may be used to connect them together, alternate connections being made at the opposite ends of the row of headers to provide for a continuous flow of water through one row of headers into the next and so forth circuitously until. the first coil section I) is reached. The supply of water enters the first header in the top row through an intake pipe 25 and thence travels through each row of the headers and their small connecting pipes circuitously across the flue and thence likewise in its downward course through the succeeding rows of headers and pipes until the first coil 6 is reached. The

water in its travel is heated to a high temperature by what would otherwise be waste heat, and the pipes 20 being small and compactly related and also in staggered relation one above the other all the waste heat is utilized to good advantage. These upper pipes, group D, I have designated as a heat economizer, which also, on account of the close juxtaposition of the pipe, act as a baffle in the upper part of the furnace. The water is under high pressure and the object of the invention is to feed it very rapidly and uninterruptedly to the furnace in a small stream and generate a large volume of steam instantaneously and continuously at any desired pressure up to 300 to 500 pounds, at normal temperature at any given pressure or superheated up to 1000 F. or above and discharging it constantly at any desired given pressure and temperature.

In this boiler the water flows downwardly through the headers and thence through a single sinuous pipe situated in successively hotter zones until. steam, either saturated or superheated, according to the quantity of water being pumped intothe boiler and the amount of fire being applied, is discharged at the hottest place in the furnace. The upper tiers of pipe represented by the-header group of pipes D heat the water by utilizing the waste heat, and the middle tiers of pipe represented by the group A of coil sections 7) bring the water to a boiling and steam generating condition and possibly some super-heating, while the lower tiers of pipe represented by the multiple arrangement of short coils C in group A superheat the steam until it is discharged at a temperature of 1000 F. and higher. Because of the construction of this boiler it allows of a large variation in the operation of the same. In operating my present boiler to deliver 175 horse power of steam at 250 pounds pressure at a temperature of 1200 F., I use a given amount of fuel or I can use less fuel and deiver the same quantity of steam slightly superheated, or use still less fuel and deliver thesaine quantity of steam atnorinal tern perature of steam at that pressure if desired. By using the same amount of fuel I can pump in an additional amount of water. and deliver 250 horse power ofsteam at normal temperature of say 400 F., or I can use even a less amount of fuel and pump in enough water to deliver 300 horse power of steam at-.100:pounds pressure at normal temperature of steam at that pressure. In fact, by controlling the amount. of fuel and water supply from pumps the capacity and temperatures of steam. can be varied to suit the 26 aremade with thereturn bends or unions 18 where exposed at the rear of the furnace.

These-branch taps 26 are placed at different elevations and connect with the vertical discharge pipes 2727 having a common discharge pipe 28 whichis connected to a settling or collecting drum 29 having a glass gauge 30 at-one side and a valved drain pipe 31 at its bottom. This glass gauge is so that a person can see whether the right valve has been opened. If the valve of a tap 26 too low down is opened, nothing but steam shows in the gauge, and when water shown in the gauge the valve at the bottom of the collecting drum is regulated to permit only enough water to escape to maintain a constant water level in the gauge thereby preventing steam from blowing out from the bottom of the drum. When the valve in a branch tap 26 has been opened and the water line located, an increased supply of water is fed from the pumps and all the pipes above that branch tap 26 are flushed out at that point and drawn off through the collecting drum 29. These branch taps permit the removal of any sediment that may have lodged in the pipe coils above such taps and flushing or washing operations take place before the sediment bakes and forms a scale in the pipe.

What I claim, is:

1. A steam generator and superheater comprising a heating chamber, a continuous coil of pipe arranged in said chamber and extending through the side-walls thereof at intervals, means for supplying water to one end of said coil and for discharging superheated steam from the other end thereof, a series of valved branches connecting intermediate parts of said coil extending outside of the heating chamber and communicating with a collecting drum having a level indicator and valved discharge connector.

2. The improvement in generating and superheating steam comprising continuously flowing water in a stream of restricted crosssection through a heating zone, withdrawing unvaporized liquid from an intermediate point of said heating zone, separating the unvaporized liquid so withdrawn from the gen- I .0 erated vapors and discharging the separated liquid, and superheating the vapors not withdrawn from said heating zone during their continued passage through the heating zone by passing heating gases in generally 6 counter current flow and in indirect contact heat exchanging relations therewith.

3. The improvement in generating and superheating steam comprising continuously flowing water in a stream of restricted cross,

20 section through a heating zone, vaporizing said water and superheating the resulting vapors during their passage therethrough by passing heating gases in generally counter current flow and in indirect contact heat ex- 25 changing relations therewith, intermittently increasing the supply of water and separate- 1y withdrawing the excess unvaporized portion passing beyond that part of the heating zone at which substantial vaporization nor- .0 mally occurs.

7 In testimony whereof I afiix my signature.

,OHAUNCEY B. FORWARD.

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