US1887182A - Multiple steam drum boiler - Google Patents

Description

Nov. 8, 1932. v I J, COUTANT 1,887,182

MULTIPLE STEAM DRUM BOILER Filed Oct. 11. 1930 2 Sheets-Sheet 1 INVENTOR:

Jv aw? A TTORNEYS- Nov. 8, 1932.

, AS C J. G. COUTANT 1,887,182

MULTIPLE STEAM DRUM BOILER Filed Oct. 11. 1930 2 Sheets-Sheet 2 INVENTOR:

BY aAa GW d W mMfW Ki MA1 gawk A TTORNEYSZ Patented Nov; 8, 1932 PATENT OFFICE JAY GOULD COUTANT, OF NEW YORK, N. 'Y.

MULTIPLE STEAM DRUM BOILER Application filed October 11, 1930, Serial No. 488,028, and in France October 14, 1929.

This invention relates to multiple steam drum boilers, and is useful in any steam boiler having two or more steam and water drums, such as the following makes, Stirling,

Ladd, Connolly, Walsh & Weidner, Erie,

' Union, Vogt.

One object hereof is to permit greatly fluctuating steam demands, such as occur in modern power houses, to be met without substantial or undesirable variation in the pressure of the steam delivered.

A specific object is to permit an increase in the output of dry steam from a given boiler, other conditions being the same. It is a well recognized disadvantage of known installations that substantial increase of steam output above normal or averageincurs an undue increase of the percentage of moisture or wetness of the steam for a given steam pressure,

thus practically limiting the useful output of the boiler. With this invention, in some cases, the boiler may be enabled to deliver as much as twice the output of steam of a given dryness and pressure.

Further objects include maintaining calm and quiet and at maximum density the water in each drum, and maintaining uniform level in the several drums. Other advantages of the improvement will be explained in the fur 3 ther description or will be understood to those conversant with the subject.

By way of explaining the principles and use of this invention reference will first be made to certain prevailing conditions in the art. Up to the present time, it has been the practice to provide a certain amount of boiler heating surface to produce a given amount of steam per hour, without allowance for certain contributing factors that control the degree of dryness of steam. For illustration, the following facts are recited.

1.All boilers, for example of the Stirling type, having more than one overhead drum for water storage and steam space are so arranged that the greater part, and in the case of a three drum boiler about 60% of the steam generated is liberated in the first or front drum; then passing through tubes to the sec- 0nd or middle drum, where about more 50 ,steam is liberated; and then passing to a third or rear drum, where the balance of about 10% steam is liberated. As the steam passes from each drum to the succeeding drum, the velocity is there increased, and it is further accelerated in the last drum while flowing toward the final outlet. Also, in this class of boilers there is utilized the steam space of only one of the drums, namely the last drum, for the precipitation of moisture from, and the drying of, the outgoing steam, under the most disadvantageous conditions.

2.-The bank of boiler tubes in the first pass, or those tubes most exposed to the ra diant heat of the fire, and in which most of the steam is generated, enter the front drum below the water level therein, and permit the rate of flow of steam and water slugs to become greater than can be relieved at high rates of steam output. The first drum becomes filled with water and slugs of water are carried over to the next drum, causing an excess of moisture in the steam at the boiler outlet.

3.In the design of Stirling type boilers with all tubes entering the drums below the water line, the steam and slugs of water discharged from the tubes shoot high into the steam space and prevent the precipitation of moisture from the outflowing steam.

4.Thus the water stored in the drums is maintained in a turbulent state, at low density and low hydrostatic head, which causes slow circulation, and prevents also the settling of solids in the water, causing dirty steam.

5.The safety valves are usually connected on the same drum with the steam outlet nozzles, namely the last or rear drum. Thus when the valves operate, the steam velocities in the rear drum are still further increased.

6.When the front drum is substantially filled with water and the rear drum is substantially empty, at high rates of steam output, while having poor circulation and increase of solids in suspension, there is a probability that the rear drum and tubes will be overheated.

7.It has been found that a too great water storage in the drums results in slow steaming,

and in fluctuations in steam pressure when loads vary.

The present invention eliminates the features of boiler design that cause the abovementioned difiiculties, and operates by the following principles and features.

1.The present invention maintains slow steam velocity in each drum, so that moisture will be able to be precipitated, thus fully utilizing the potential value of the steam space in each drum.

2.It provides the necessary drum volume to carry out the above stated functions in relation to the steam demands. By utilizing the upper half of each drum for steam space and for the precipitation of moisture, and the lower half for water storage, the water storage is not so large-as to prevent fast steaming or to cause fluctuations in steam pressure when serving varying loads. It has been determined that about one cubic meter of drum volume should be provided for each 32000 kilograms of steam produced per hour.

3.With this invention, when steam and water slugs enter each of the drums above the water line, they discharge against a baflle, delivering a quantity of water proportional to the steam output, so as thereby to maintain a uniform water level in all the drums, and with the Water in a relative calm state and at a maximum density, assuring rapid circulation and the settling of solid matter.

4.-Safety valves are placed on more than one, or on all the drums, and are so arranged 4 that the steam velocity in the drums will not be increased when the valves operate.

This invention also includes the principle and means of taking steam from multiple steam drum boilers, with outputs corresponding to the steam space of each drum, also certain exterior and interior drum and collector tube connections.

All of these features characterize this invention for designing or perfecting steam boilers to produce increase in the output of dry steam, which will be better understood from the accompanying drawings illustrating the invention and the description following.

Fig. 1 is a diagrammatic vertical section taken through the drums of a conventional type Stirling boiler, equipped with dry pans, external and internal tube connections, and safety valve outlets.

Fig. 2 is a vertical section at the drums of a modern semi-verti cal water tube boiler with external tube connections, some entering above the water level, and showing the entering tubes, bafiles and safety valve outlets.

Fig. 3 is a Vertical section at the drums of a different semi-vertical water tube boiler with external tubes and collector connections.

Fig. 4 is afivertical section at drum of a modified design of high pressure two-drum, cross drum, forged steel sectional header boiler, equipped with external and internal tubes, collector connections and safety valve outlets.

Fig. 5 is a similar section showing a safety valve outlet detail.

Fig. 6 is a similar section showing details of the dry pan in each drum; and Fig. 7 is a modified dry pan construction in similar view.

Fig. 8 is a top plan View, for example of the third or rear drum in Fig. 1, showing the longitudinal spacing of-the various tubes, which spacing carries through to all drums and the boiler.

Fig. 9 is a view similar to Fig. 4 but showing only portions of the drums and upper header of Fig. 4, and with a modified arrangement of connections.

It is believed to be new to control as described the water storage space and the steam space in the drums as the contributin factors that govern the ability of a steam oiler to generate dry steam at a given rate of output. For example, the conventional type of Stirling boiler utilizes only one-third of the available drum steam space for the precipitation of moisture and consequent drying of the steam, namely the space in one of the three drums, while the same boiler (Fig. 1), equipped according to the present invention, will utilize the steam space in all the drums.

For illustration, the boiler in Fig. 1 is filled with water to line O0, where it can be maintained substantially constant, due to the improved distribution of steam and water to each of the three drums, 1, 2 and 3, in relation to the amount of outgoing steam.

The tube bank 4, in the first or front pass, is exposed to the hottest heat of. the fire, and generates approximately 60% of the total steam, 17% of which may pass through the extreme lowest row of tubes 5, which are extended through drum 1, then by tubes 6 delivering into the rear drum 3 against a louvre bafile 7.

The tube bank 4 also liberates directly to the front drum 1 approximately 43% of the steam, 10% of which may subsequently pass through tubes 9 to drum 3.

The second lowest row of tubes in bank 4 is shown carried through drum 1 by extension tube 8 into the middle drum 2.

The middle bank of tubes 10 may generate 30% of the steam. and is shown discharging directly to drum 2. It is supplemented by that delivered by tube 8.

The rear or third tube bank 11, at the left of Fig. 1, generates say 10% of the steam and discharges wholly to drum 3, and approximates 37% of steam liberated in drum 3, considering that tube 5, 6 discharges also directly into this drum. The pressures in the three drums being equal, the inlet orifices to each of the dry pans 12, which extend nearly the full length each drum, offer equal resistance to outlet flow. Therefore, approximately rau 33 of the steam generated will be selected from each drum. Any unequal pressure between drums would be equalized by tubes 15, interconnecting the dry pan spaces. Safety valve outlets 13 are placed on each drum, so as not to increase steam Velocities from. any drum in case a valve should operate. The final steam outlet 113, is on the third drum 3, as usual.

There is a. dry pipe 14 located in the dry pan of drum 3 and connected to steam outlet nozzle 113, which is for the uniform selection of steam in the dry pan over the length of drum 3. I

Fig. 2 shows a modern semi-vertical type of boiler the drums of which are shown filled with water to the level 00, this being maintained constant due to the described distribution of steam and water in relation to the steam output of the drums. I

The front bank of tubes 16, which generates about 66% of steam, is so arranged that the first, third, fifth, etc., rows of tubes will lead to the front drum 1, and the alternate or second, fourth, etc., rows to the middle drum 2, liberatin about 33% of the steam to each drum 1 and 2 by this distribution.

It will be noticed that the tubes of the bank 16 that are exposed to the radiant heat of the fire and therefore generate most of the steam, enter drums 1 and 2 above the water line,

and they are shown discharging the slugs of water and steam against plates or baffles 17, which break up the steam velocity and the slugs of water, maintaining the steam and water spaces of the drums in a relatively calm and quiet state.

The middle bank of tubes 18 deliver approximately 20% of steam and wholly to drum 2. This flows through circulating tubes 19 to drum 3.

The pressures in the three drums are nearly equal, and about ita of the steam is taken from each drum, either through a dry pan 12 or direct by a longitudinal series of tubes 20, connecting to steam outlet or collector 21.

Fig. 3 shows a proposed semi-vertical water tube boiler with two drums, filled with water to line 0-0, and arranged with a front bank of tubes22 with alternate rows leading to drum 1 and the next row to drum 2, an arrangement that will deliver approximately of the steam to each drum. The arrangement provides for tubes 23 connecting direct from the dry pan 12 in each drum to superheater collector header 24. Each drum is equipped with safety valve outlets 13 so arranged that the selection of dry steam by the dry pans 12 will not be interfered with when either of the safety valves operates, preferably by taking off from the steam space direct and not through the regular steamoutlet or dry pan.

' The usual cross drum boilers are limited to one drum, and this is limited in diameter to about inches owing to comparative expense with other boilers, shipping weight etc.

In Fig. 1 is shown a modern cross drum boiler, with an additional drum provided, and with a proposed high pressure and high output forged steel sectional header boiler. \Vhen made with two or more drums such boiler may be filled with water to level 0O, which is maintained in a calm state of maximum density and hydrostatic head as described. The water descends through one Or two water supply tubes 25 leading from the drums to a lower header 27. The water passes downward and thence into and through the first and second banks of boiler tubes 26 and 26", where steam is generated, passing up to the inclined sectional upper header27 i The steam and slugs of water rising in one of these headers are then passed through tubes 28 to the first drum 1. The next alternate sectional header may connect by tubes 28 to drum 1; the steam and water slugs being then passed through tubes 29, located in drum 1, and through tubes 30 leadin to drum 2 or exterior connections could be made as shown in Fig. 9 at 28" which is a more practical arrangement.

The steam and water slugs are thereby discharged substantially equally into the two drums above the water line, striking louvre bafiies 31; the steam is liberated and the water falls like rain on the Water held in storage, thus drying the steam. The water in circulation is relatively calm, at maximum density and hydrostatic head,,thus assuring rapid circulation.

The two or more drum cross drum boiler of Fig. 4, with this improvement, permits sometimes double the steam output, without increasing the moisture content in the steam.

The steam is collected uniformly the full length of each drum by dr pans 12, and then passes direct through tubes 32 to a steam outlet header or superheater collector 33. It has been the practice to place safety valves over dry pans, and when such valves operated there has been an excessive Velocity of steam entering the dry pan, and this has picked up and entrained much moisture. This invention includes a dry pan 34 arranged with a loose sleeve 35, extending through the dry pan, as shown in Fig. 5; by this arrangement, safety valve operation cannot substantially increase the moisture content in outgoing steam, for it takes steam direct from the drum steam space and not from the dry pan.

The equalization of steam outflow from the several drums may be controlled by the adjustment of the dry pan inlets, in a manner as shown in Figs. Gand 7 Thus the steam inlet area. 36 may be adjusted as in Fig. 6 by a threaded bolt 38. The adjustment of the inlets to the dry pans also gives control as sisting to maintain a uniform water level in all the drums. The control of steam inlet area 36 to each dry pan 37 may be made from outside of drum as in Fig. 7 by a threaded nut 39, which raises and lowers a bolt 40 supporting the pan 37. V

The present invention may be summed up [I as relating to the class of boilers having a' system of water tubes ex osed to the furnace and a plurality of elevated sieam-and-water drums each receiving steam from and supplyin g water to the tube system; and as comprising the combination with such drums, each having its steam space substantially not smaller than its water space, and such tube system, the same having connections distributing steam separately to the drums, preferably at rates approximately proportional to' the volumes of the steam spaces of the respective drums, and the connections to each drum entering the same substantiall or uniformly along its entire length, and said drums having steam outlets from the steam spaces thereof adapted to deliver steam therefrom, preferably at rates approximately proportional to the volumes of the steam spaces of the respective drums, and the outlets from each drum leaving the same, or the steam space thereof, substantially along its length so as to collect steam substantially uniformly over the length of the water space. By the described arrangement of the inlets and outlet-s of each drum the flow of steam from the inlets to the outlets is a substantially transverse and short flow, and therefore at relatively low velocity, and preferably at aproximately equivalent velocities in the several drums; and there will be no high speed racing of steam longitudinally in the steam space of any drum to reach the outlet thereof, in consequence of which full opportunity is afforded for the precipitation of moisture,

and the steam flow transversely through the drum will not tend to pick up the water from the water space; consequently the dryness of the steam is maintainable even with greatly increased generation of steam to meet fluctuating demands.

In stating the apportioning of distribution of steam to the several drums by the relation thereof to the steam spaces of the drums. this has reference to the preferred or minimum steam spaces which. in each drum, may be substantially equal to the water space, or one half of the volume of the drum; it is not intended to exclude an arrangement otherwise equivalent of that illustrated but wherein the steam space is enlarged to provide excess volume and corresponding increase in steam drying effect.

The arrangement of the steam outlets from the steam space of each of the drums, namely along substantially the entire length of the drum, may be afforded in various ways, for example by an elongated series of separate outlet pipes, but is illustratively shown as effected by the use of a dry pan, pipe or collector, the interior or passage of which is not considered as part of the steam space-of the drum. The dry pan extends substantially the entire length of the drum so that the steam may flow into the dry pan passage from the steam space along substantially its entire length, avoidini. the usual longitudinal flow and inherent high velocity.

The outflow of steam from the steam spaces of the drums to which reference has been made is a final outflow, and has no reference to a mere circulating connection from drum to drum. such as the pipes 9 or 9 of Fig. 1 or the pipes 19 of Fig. 2, wherein may occur a minor or pressure equalizing flow between drums. The steam outlets of this invention extend fom the steam spaces of the drums into the dry passages and thereafter do not reenter such steam spaces, but pass on to the final outlet. Thus in Fig. 1 the final steam outlet 113 receives steam from the steam spaces of all of the drums without the necessity of the steam so received from any drum having to pass through the steam space of any other drum.

The water level is normally substantially the same in all of the drums, as is customary in the class of boiler referred to, and the level maybe determined and controlled in any usual manner, for example under observation by means of a water gage 101 attached to one of the drums, or by an automatic boiler feed regulator. Preferably the water volume of each drum is maintained small to ensure fast steaming qualities, while maintaining enou h water to ensure proper recirculation to the boiler tubes. Relativel small drums therefore may be employed, wherein the water and steam spaces are approximately equal. The several drums are preferably of the same size, but if unequal the one with the larger steam space will preferablv receive steam at proportionately greater rate as stated.

Having described several illustrative embodiments of the invention it is stated that it is not intended to limit the invention to the specifically illustrated features of combination, arrangement or structure except to the extent set forth in the accompanying claims.

What is claimed is:

1. A steam boiler of the class having a system of water tubes exposed to furnace heat and a plurality of elevated steam-and-water drums all delivering to a common final outlet and each receiving steam and water from and supplying water to the tube system and each such drum having both its inlet and its outlet connections distributed along its length whereby to secure transverse flow and substantially to avoid longitudinal flow within the drum so to minimize the steam velocity within each drum; and said boiler characterized by the particular combination of said steam-and-water drums and said water tube system wherein the steam connections extending from the tube system to the respective drums are arranged or apportioned to distribute to the respective drums the steam generated in the tube system at rates by weight approximately proportional to the volumes of the steam spaces of the respective drums and the steam outlets from the respective drums are adapted. to deliver steam therefrom at rates also approximately proportional to the respective steam spaces'whereby there will be maintained within all of said drums transverse flow of steam from inlets to outlets at approximately equal and therefore uniformly minimum velocities.

2. A steam boiler of the class having a system of water tubes exposed to furnace heat and a plurality of elevated steam-and-water drums all delivering to a common final outlet and each receiving steam and water from and supplying water to the tube system and each such drum having both its inlet and its outlet connections distributed along its length whereby to secure transverse flow and substantially to avoid longitudinal flow within the drum so to minimize the steam velocity within each drum; and said boiler characterized by the particular combination of said steam-and-water drums and said water tube system wherein the steam connections extending from the tube system to the respective drums are arranged or apportioned to distribute to the respective drums the steam generated in the tube system at rates approximately proportional to the volumes of the steam spaces of the respective drums whereby there will be maintained within all of said drums transverse flow of steam at approximately equal pressures and at approximately equal and therefore uniformly minimum velocities.

3. A steam boiler constructed and operating as in claim 2 and characterized further by a safety valve system comprising a separate safety valve connection for each drum and each of the several safety valve connections being connected into its drum to receive steam directly from the steam space of the drum rather'than from or through the aforesaid steam outlet connections of the drum.

4. A steam boiler of the class having a sysflow within the drum so to minimize the steam velocity within each drum; and said boiler characterized by the particular combination of said steam-and-water drums and said water tube system wherein the steam connections extending from the tube system to the respective drums are arranged or apportioned to distribute to the respective drums the steam generated in the tube system at rates approximately proportional to the volumes of the steam spaces of the respective drums and the steam outlets from the respective drums are adapted to deliver steam therefrom at ratesproportional to the receipt of steam therein from the tube system whereby there will be maintained within all of said drums transverse flow of steam at approximately equal velocities, and approximately equal water densities and levels.

5. In a boiler of the class having a system of water tubes exposed to furnace heat and a plurality of elevated steam-and-water drums each receiving steam from and supplying water to the tube system, the combination with such drums, each drum having substantial steam and water spaces, and such tube system, the same having connections distributing steam separately to said drums, and such connections to each drum entering the drum at inlets arranged along substantially the entire length of the drum, and each of said drums having a steam outlet consisting of a longitudinal steam collecting dry passage Within the upper part of the steam space provided with a port or ports extending substan- 1

Images