US1942179A - Feed water heater - Google Patents

Description

Filed NOV. 15. 1928 INVENTORJ A TTORNE Y.

Patented Jan. 2, 1934 UNITED STATES P AT FEED WATER HEATER Auguste Magis assignors to The Superheater Company,

York, N. Y.

Application November and Andre Huet, Paris, France,

New

15, 1928, Serial No.

319,584, and in France May 14, 1928 1 Claim.

The present invention has for its object a process of heating the feed-water for steam boilers, and is particularly applicable to movable boilers such as those for locomotives.

The invention likewise includes apparatus whereby the process is carried out.

The process consists in effecting the heating of the feed-water in two successive stages. In the first of these the water is heated by means of the exhaust steam from the engine and in the second by means of the combustion gases which have given up their heat in the boiler proper. The residual heat in these combustion gases is preferably absorbed in the second stage by means of an intermediate fluid or a primary fluid working in a closed circuit so as to avoid the well known annoyances resulting from scaling and to assure at the same time the greatest flexibility and efficiency of the process. In the apparatus for carrying out this invention, the cold feedwater coming from the injector flows first through a heater having the form, for example, of a drum where the steam coming from the engine will effect the first heating up to a temperature of about C. for example, the steam either mixing with the water or heating it without coming into contact with it. The feed-water will then pass to a second heat exchanger or drum heated indirectly by the gases of combustion by a tube bundle through which the intermediate fluid circulates.

If in the first stage the heating of the feedwater is performed by mixing the steam from the engines with it, this water will then contain a certain amount of oil brought in with the steam and it will then be necessary to separate this oil out before forcing the water into the boiler- This separation of the oil will occur in the second heater first because the feed-water circulates very slowly in the drum of this heat exchanger and also on account of the different cross-section of the heater as compared with the tubes that bring in the water and by which it leaves, and the separation will be further favored by the arrangement of baflies against which the emulsion of oil and water will deposit the oil, this oil being then conducted to the upper portion of the drum from which it can easily be blown off by a properly arranged tube.

The description which is to follow in connection with the annexed drawing will make clear the manner in which we carry out our invention.

Fig. 1 is a Vertic l, longitudinal section, partly diagrammatic in character, of the forward part of a locomotive equipped with a heating apparatus according to our invention; and

Fig. 2 is a view on an enlarged scale of the heating drum used in the second step of the process.

The feed-water delivered by the pipe at flows into the first heat interchanger or drum b where it is heated up to a temperature approximating 80 C. by the exhaust steam from the cylinder conducted to the heater by means of the connection c which forms a branch from the exhaust nozzle d. The exhaust steam heats the feed-water either by directly mixing with it or by any other means. The feed-water having been heated in this first stage is forced by means of the pump f and pipe '1 to the second heat exchanger in drum 9 where it undergoes a secand heating before being carried by pipe Z into the boiler p. If the heater b is of the indirect type, the pump I may be omitted. 75

The drum 9 is heated by a series of tubes through which the intermediate fluid circulates, these tubes forming a part of the closed circuits h h b 71. and whose serpentine heat absorbing portions i i i i are located in the path of the combustion gases coming from the boiler proper. When a fluid vaporizable under the conditions of use is employed in the circuits h, the intermediate fluid vaporized in such serpentine heater portions 2' i i 2' rises to a series of condensing tubes arranged in the interior of the drum g. These tubes take a form preferably such as shown. Such condensing tubes are illustrated in detail in Fig. 2 and comprise lower sections or chambers 7' 7' 7' having relatively large cross-sectional areas and which may take the form of headers. From the upper portions of headers 7' etc, extend upper tube sections it in which the major part of the condensation occurs. The condensate collects in chambers y' etc., and drains from thence into the serpentines i etc. In order to facilitate the circulation of the liquid and to avoid interference between condensate passing to serpentines 1' etc. and vapor coming therefrom, the riser portions of serpentines 2' etc. are carried up into chambers 7' etc., to a point well above the lower outlets of these chambers as shown at 2'1, (Fig. 2) so that there is no tendency for the condensate to pass into the risers of the serpentines. In order to minimize the number of openings through the drum 9, the enlargements 7' etc., may have downward tubular extensions 7'1 thereon extending through the drum g as shown in Fig. 2, and the upper ends of the risers from the serpentines may then be passed into sections 1 etc., through the extensions 7'1 in alinement with tubes 70, all as also shown in Fig. 2. This arrangement is illustrated only diagrammatically in Fig. 1 because of the small scale of this figure. The enlargement of the condensing tubes at 7' etc., reduces the tendency of the condensate from sections is to drop into the upper ends of the riser tubes, as the liquid condensate tends to hug the wall of sections 7' etc., and so is guided away from the mouths of the riser tubes. The tubes 7 9' 7' 7' (see Fig. 2) having a relatively large cross-sectional area have extending from them the condensing tubes 70 in which the intermediate fluid is condensed.

By its condensation the intermediate fluid gives the greatest part of its heat which it has absorbed from the combustion gases to the water in the drum 9. This water flows from right to left as shown in Fig. 1, its temperature increasing more and more since the temperature of the tubes h W, 71 71. is successively higher on account of the relative proximity to the source of the gases. It will be seen that the heater b draws ofi steam from the exhaust nozzle d which would otherwise be effective in creating a draft through stack 6. Heater 1) thereby tends to reduce the maximum output of the locomotive by reducing the maximum rate at which fuel can be burned. The heat absorbing elements i i i and 1, how- 'ever, lie in the path of the gases flowing to stack e and reduce the temperature and, con equently, the volume of the gaseous products before they come into contact with the steam from exhaust nozzle 11. The nozzle 01 is therefore able to force thru the stack-e a greater weight of gases with the exhaust steam available than if the gases had not first contacted with the elements 2' i i and i*, so that, in the arrangement herein disclosed, the added efiiciency and capacity to be expected from the use of feedwater heaters 17 and y are obtained with substantially no penalty so far as the fuel burning capacity of a given locomotive is concerned.

The separation of the oil which the feed-water may contain is accomplished in the inner part of the drum 9/, partly on account of slow circulation of the water within the drum due to its larger size and partly on account of the arrangement of the special bafiles m. Alternate baffles m have two sections, as will be seen from Fig. 2, set at a right-angle or nearly at a right-angle so the upper sections of the baiiles may present a surface slightly inclined to the horizontal and are provided with openings m or otherwise take the shape of separate plates n which, by their contact with the water, separate the oil and cause it to gather in the upper portion of the drum from which it is finally taken off by means of the discharge tube 0- at a suitable level. Suitable valves Z1 and 01 are placed in the water and oil outlet tubes respectively so that the water level in the drum may be kept at such a height as to obtain an optimum separation of the oil.

It is obvious that modifications in the details may be made in the arrangement above described without departing from the spirit of the invention.

We claim:

In apparatus of the class described, a feed water heater of the closed type receiving feed water containing oil and having a feed water drum enclosing heat delivering members, means for heating said members, and a baflie system in said drum having means arranged to direct the flow of feed Water in a serpentine course over said heating members, said baflie system having substantially horizontal sections beneath which i providing an outlet for oily water from said drum at a level above that of said sections.

AUGU$TE MAGIS. ANDRE HUET.

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