US1748574A - Liquid heater - Google Patents

Description

Feb. 25, 1930. w. D. LA MONT LIQUID HEATER F iled June 24, 1927 INVENTQOR H j 3 9 Mfl d 6 0O 7 L M 4 WJ/ M a Patented Feb. 25, 1930 UNITED STATES PATENT OFFICE \immrua'. noUeLAs LA MONT, or LAncnmoN'r, NEW YORK, ASSIGNOR 'ro LA MONT COB-' .ronATIoN, on NEW YORK, N. Y.,

A CORPORATION OF NEW YORK LIQUID HEATER Application, filed June 24,

water for the generator has been. pumped.

therethrough in order to utilize some of the wasteheat of the gases in bringing the feed water up to or near the temperature of the water in the generator. The heat transfer from the gases to the water isordinarily rather poor owing to the fact that the gases are relatively cool and therefore the heat head between the gases and the water is not great. This has resulted in a comparatively small heat absorption unless the surface of the economizer is of uneconomically large extent. A further difiiculty arises particularly when relatively large economizers are used, owing to the fact that the feed water passing through'the economizer circulates at a comparatively low rate of speed, since the demand for feed by the ordinary steam generator is not great and if the heating surfaceof the economizer is sufiiciently large'to provide adequate heat transfer capacity the water circulation drops'to a point where it greatly decreases the heat transfer efliciency. I

v For most purposes the flow of feed water through the economizer may be intermittent since the economizer is usually placed in a heat zone sufiiciently lowto prevent burning of the tubes or elements even though they may run .dry for considerable periods of time. Sometimes, however, where the economizer may be situated in a suflieiently hot zone it may be desirable toprovide for flooding the economizer whenever the demand for feed in the steam generator ceases. This can be ef-' fected by keeping the economizer constantly in communication with the feed line but varying the amount of water which flows from the economizer into the generator in accordance with the demands of the latter 'for feed water.

Thus, for example, when the feed valve to.

the generator is closed and Water is no longer drawn off through the economizer, the feed I water flowing into the tubes gradually fills 1927. Serial No. 201,173.

economizer faster than it flows in throughthe injection orifices into the tubes. The tubes which have been flooded W111 be rapidly drained and the incoming water willthen flow-down in the form of a film on the inner walls of the economizer tubes, thus presenting the heat transfer advantages which have been described above. I

The invention isvery flexible in its nature and maybe applied in connection with any ordinary type of steam or other vapor generator and marked increases in over-all eflicleney in the generation of steam from a unit quantity of e1 will'be had. At the same time, the system is simple and rugged anddoes not introduce delicate devices which are liable to get out of order.

e present invention also possesses the notable advantagethat the economizer can readily be used to generate large quantities of steam. This is'of. great importance where the economizer is used in conjunction with a steam generator having very high peak loads. It is possible in suchcases to use the economizer mainly for heating water at lower ratings of the necessary to ta e care of peak loads the rat ing can beincreased to a point which would. be hopelessly uneconomical for the generator alone. The hi h temperature of the stack gases will then e sufficient to generate large I quantities of steam in the economizer and in.v

this manner high peakloads can be taken care of with a muc smaller generator and with out undue losses during peak load operation.

'The invention will be described in greater detail in connection with the annexed drawings, in which- 1 Figure 1 is a vertical section through a generator and economizer of the present invention; Figure 2 is a detail showing .the jet tube with an orifice therein for regulating the amount of water entering an economizer tube.

gpnerator and when it becomes A common conventional type of water tube steam generator is illustrated having a drum 1, front and rear tube header sections 2 and 3 connecting tubes 4 and baflies 5. The economizer consisting in upper headers 6, lower headers 7 and tubes 8 is arranged in the stack in such a manner that the lower manifold or pot 9 into which the lower headers 7 discharge is at a higher level than the drum 1 and is connected thereto by the pipes 10 and 11, the former extending from-the lower end of the pot to the water space and the latter from the upper end of the pot to the steam space. The pipe 10 is provided with a valve 12 and the pipe 11 with a valve 13 which may be operated manually or automatically. For some purposes it may be desirable 'to provide an automatic relief valve at 13 which will open when steam pressure in the economizer exceeds the normal pressure of the feed. Feed from the feed line passes through the pipe 14 into the upper headers 6 and the flow may be controlled by the valve 15.

The upper headers 6 are constructed as Shown in my co-pending application Serial No. 32,064, filed May 22, 1925, the essential portions of which construction are shown in Figure 2 of this case. Each of the tubes '8 is connected at one end to the distributing header 6, which header is drilled with'openings 32 to receive the upper ends of the tubes 8, these openings being countersunk upon the inside of the headers so that the ends of thetubes may be expanded into the openings and thus locked on the headers. The water is projected into the tubes in the form of jets which are formed by jet openings 36 in a jet manifold38 which is removably held within the header 28. This manifold, as shown in Figure 2, is in the form of a tube semi-circular in cross section which fits the inner wall curvature of the header.

The opening in the header-through which .the tool is inserted to expand the tubes 8 is closed by a gasket or bar 50 of substantially segmental cross section, this bar being tapped to receive screws 52 by which it may be held tightly against the inner surface of the header and thus close the header openings, and nuts 54 on the screws being adapted to bear against flat surfaces on the header and thus draw the bar 50 tightly against the inner wall of the tube 6. The water and steam are separated in the pot 9, the steam passing through the pipe. 11 and into the steam space of the drum 1, and the water passing through the pipe 10 into the water space.

Where the heat applied to the economizer tubesis sufliciently high to cause danger of burning out should the tubes-be permitted to run dry, the economizer may be operated as follows: The water level control 16 operates to open and close the valves 12 and 13, the valve 15 being open. A uniform delivery of feed to the upper headers 6 takes place, the water flowing down the tubes in the form of a film and steam and water being separated in the pot 9, as described above. When, however, the water level in the drum 1 rises the valves 12 and 13 gradually close and the water flowing into the upper headers 6 gradually becomes greater than the amount which flows out through the pipe 10. The water will then rise, in the pot 9 and when finally the valves 12 and 13 are completely closed, the water will rise and completely fill the tubes 8, stopping further feed and insuring the tubes from burning out. upon the water level in the drum 1 again drops and the valve 12 is opened water flows out of the pot 9 faster than it is fed in and the tubes are'rapidly drained and again operate on a film basis.

The present invention is applicable to any type of primary steam generator and is in no sense limited to the particular type of inclined water tube generator shown in the drawings or even to water tube generators as a class.

The economizers of the present invention operate for the most part on a pure film basis, that is to say, the amount of water injected into the upper ends of the tubes is so directed that it forms a film, on the inner walls of the tubes which film is extended downwardly for the full length of the tubes by gravity. It should be understood, however, that economizers of the present When" thereinvention can also be operated in such a .100

manner as to produce a film over a portion only of the inner walls'of the tubes. In general if the amount of water introduced into the tubes is less than that suflicient to fill the tubes, a film will be formed at least on part of the tube walls. The present invention is not limited therefore to economizers in which the film extends the full length of the tubes but on the contrary includes economizers where, during part of the time, the tubes may be partially extending only over a portion of their inner surface. The invention has been described in detail in connection with the drawings in which the economizers shown are vertical economizers. Where the conditions of space permits this design presents many advantages, as the film formed in the tubes is rapidly and uniformly extended down the tubes by gravity. some cases, however, particularly where the economizers of the present invention must be applied to already existing steam generators, the arrangement of space is such as to make it difficult or impossible to provide for a vertical or inclined economizer. In such cases it is possible to utilize a substantially horizontal or only slightly inclined economizer, the film production being less perfect than in a vertical or substantially vertical installation filled with water and have films i but being satisfactory for most purposes. It

is even possible in some cases to provide an economizer in which the flow of water is actually uphill, which ma y be necessary where a down-curvlng duct is encountered and where it is desired to cause the gases to flow'counter to the flow of water in order to obtain the maximum extraction of heat. Where the upsuperior intheirheat absorbing and steam- 8 and is in no sense limited to steam generators.

ing capacity to the economizers'used hitherto and in some installations the space requirements may render these constructions desirable or necessary,

The invention has been described in conmizer elements, a connection from the lower end of the elements to the generator whereby water flows by gravity into the generator, and

means governed by the level of liquid in the.

generator for controlling the liquid flow from the economizer elements ,into the generator whereby when said flow ceases the economizer elements-become flooded.

2. Apparatus according to claim 1, in which means are provided for separating vapor and liquid discharged from the economizer elements.

Signed at New York, New York, this 21st day of June, 1927.

' WALTER DQU GLAS LA MONT.

nection with economizers used. with steam generators. Obviously of course, it is equal- 1y applicable to economizers used in connec-- 'tion' with any other kind of vapor generator The preferred form of invention which hasv been described-in detail and in which water or other liquid is fed into the upper ends of j I the inclined economiz er tubes in most cases 1s the most advantageous and best arrangement. It should be understood, however,

that the advantages, which are inherent in a positive distribution to all of the economizer elements, are also important in that no ments as described and illustrated in the,

stagnation or reverse circulation can take place in individual elements orkgroups of elements, such as occurs in the ordinary type of ,economizer in which convection circulation and dead spots are possible. The advantages of positive distribution are, of course, not limited to the preferred embodiment where tlie lifquid passes down the tubes in the form 0 a lm and are equally applicable to film or full element economizers. 'Anysuitable means can be used to bring about this positrve distribution such as for example the pro- VlSlOIl of inlet orifices in the'e'conomizer elepreferred embodiment. v

Having thus described my invention, what is claimed as new is-' 1. In combination, a vapor generator heated by heating gases, non-horizontal economizer elements in the path of said gases and at a level above that of the liquid in the generator, means for introducing .feed liquid into the upper ends of the economizer elements in amounts normally insufiicient to fill the elements, means for dischar ing liquid and vapor from the lower ends oi the econo-

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