US1889739A - Desuperheater - Google Patents

Description

Dec. 6, 1932. w. H. ARMACOST 1,

DESUPERHEATER Filed May 29, 1931 2 Sheets-She et 1 INVENTOR W1 lbw-HA macos-t ATTORNEY Dec. 6, 1932.

W. H. ARMACOST DESUIERHEATER Filed May 29, 19

31 2 Sheets-Sheet 2 INVENTOR Wilbur H-Lrma 'cost. BY

ATTORNEY Patented Dec. 6 1932 UNITED STATES- PATENT' OFFICE WILBUR H. ARMAGOST, OF NEW YORK, N. Y., ASSIGNOR TO THE SUPERHEATER COMPANY, OF NEW YORK, N. Y.

DESUPERHEATER Application iled May 29,

My invention relates to superheaters having means for controlling the final temperature of the superheated motive fluid and aims to provide a method of operation and an apparatus adapted to control the final vapor temperature within close limits.

The novel features of my invention are pointed out in the appended claims. The invention itself, however, together with its ob jects and advantages, will best be understood from the following detailed description of illustrative particular apparatus adapted to carry out my improved method. The said apparatus is illustrated in the accompanying drawings in which:

' Fig. 1 is a sectional elevation of a steam boiler having a superheater combined therewith in accordance with my invention.

Fig. 2 is a transverse section through an intermediate header of the superheating apparatus illustrated in Fig. 1, the section of Fig. 2 being taken to correspond with line 22 on Fig. 3.

Fig. 3 is a detail view of the coil shown 5 within the header in Fig. 2 and looking in the direction of the arrows 3-3 on Fig. 2.

Fig. i is a detail sectional view of thewater regulating means shown in Fig.1.

In steam power plants, the use of high degrees of superheat is becoming increasingly popular. This,.however, involves as a rule some means for limiting the final temperature of the steam so that it shall not damage the prime mover or other parts of the'appa- 5 ratus by overrunning a predetermined maximum. The higher the steam temperature,

however, the better the efficiency of the prime mover so that a close degree of regulation of the final steam temperature is very desirable in order to maintain the eiiiciency as high as possible without danger of damaging the prime mover. V

In accordance with my invention,'I obtain the objects set out above by superheating steam, or like motive fluid, in two steps and introducing water, or other liquid corresponding to the vapor used, into the confined steam or vapor being superheated at a point intermediate the two superheating steps, regulating the amount of liquid so added in ac- 1931.. Serial no. 511M384.

cordance with the final temperature of the superheated vapor to maintain the final temi perature very close to the maximum permit: ted without danger of its overrunning sufch' mammum. I

In the apparatusin accordance with myin+ vention illustrated in the drawings, a boiler of known type is indicated generally by character 10. Boiler 10 isi shown as having a steam water drum 12 and also a generating bank of straight horizontally inclined tubes V 14, 14 below which is a slag screen bank having tubes 16, 16. Boiler 10 is providedw'ith the usual means for causing a thermosyphoni'c' circulation through tubes' l4 and 16, suchmeans including circulators 18,18. The tubes 16 of the slag screen bank are shown as spaced from the tubes 14 in a known man ner providing a space or chamber 20 below the tubes let and the circulators 18 as spaced from the tubes .14 and above the latter to'pro} vide a space 22. As shown, space 22 is utilized to receive a set of primary superheating elements 24 and space 20 is utilized tore- .ceive a set of secondary superheating ele ments 26. Steam is supplied to the primary elements2t through a conduit 28 and intake header 30 and the setsof primary and secondary superheating elements2et and 26 are connected for series flow of the steam through the sets by means of intermediate header 32, conduit 34 and second intermediate header 86. Steam passes from the intake header 30 to the intermediate header 32 through the elements at and-thence through the conduit 35L 5 to the second intermediate header 36. From the intermediate header 36 the steam flows through the set of secondary superheating elements 26 to the outlet header .38 and thence to theprimemover or other steam 9 consuming apparatus through the main. 40; For limiting and regulating the temperature of the steam passing off through conduit or main-40, I provide meansfor introducing liquid into thesteam' at a point intermediate the outlet ends of the primary superheating elements 24and the inlet ends ofthe secondary superheating elements 26. The'ar'rangement illustrated for'this purpose comprises a spraying coil havingduplicate parts A2,.l0

42 and arranged in the lower intermediate header 36. Each of the coil parts 42 has spray outlets 44, 44 for spraying water into the steam within the conduit 36 and has also a plurality of unperforated lengths 46, 46 through whichthe water passes so as to be heated by the superheated steam in the conduit before being brought into direct contact withv such steam by beingsprayed into it. By passing water through the pre-heating portions 46 before spraying it into the steam, the temperature of the water is raised sufficiently so that it is quickly and completely evaporated before entering the secondary superheating elements 26. Preferably, the flui d in portions 46 is heated to the point that some of it is evaporated before it is sprayed into the vapor. When the liquid supplied to portions 46 is already at or near the boiling point, as when it is taken from the boiler, this is easily accomplished. vaporization of thesprayed Water is facilitated further by the fact that the pressure in portions 46 is necessarily higher than'in header 86. If

some steam is formed in portions 46, the water therein is superheatedco mpar'ed with the boiling point ofwater at the pressure in header 36. Some of the water therefore flashes into steam as soon as itpasses through V the spray orifices thereby assisting in the atomizing step and producing such a large Water surface that all the wateris immediately vaporized by contact with the superheated steam. Water is introduced into the preheating and spraying coils 42 through a central nipple 48 which passes through the Wall of the header 36 and .is preferably welded thereto as indicated at 50 to prevent leakage along the outer wall of the nipple.

The nipple 48 is connected by a suitable cou-' pling, preferably of the ordinary threaded type, to a water supply pipe 52. Water supplied through pipe 52 may come from any suitable source and'may be supplied from the drum 12 of the boiler 10.

The amount of water sprayed into the steam between the primary and secondary superheaters is regulated in accordance with the temperature of the steam in the main 40. Preferably this is accomplished automatically and for this purpose I have illustrated in pipe 52 the casing 54 of a known type of thermostatically controlled valve 56, illussteam therein.

trated in detail in Fig. 4. The position of the valve 56 is controlled by a thermostat 58 which passes through the wall of conduit 40 thermostat 58. The valve 56 is moved by the spring 62 in the reverse direction whenever the temperature of the thermostat 58 decreases to cut off the amount of water going to the spray apertures 44.

While I have illustrated and described in detail a particular apparatus and method of operation, it will be understood that I do not limit myself to the details of the disclosure and that the appended claims are to be taken in their broad sense.

- What I claim is:

1. The method of superheating vapor comprising superheating a confined current of vapor, spraying liquid into said current after said superheating step, superheating said cur rent a second time, regulating the rate of liquid supply to said spraying step in accordance with the temperature of the vapor cur rent after said second superheating step, and

preheating the liquid to be sprayed into the vapor sufiiciently so that substantially all the sprayed liquid is vaporized prior to said second superheating step.

2. The method as set gether with the step of preheating the liquid to be sprayed into the vapor by transferring heat to. the liquid from the confined current of superheated vapor. y

3,. The method as set forth in claim 1 together with the step of preheating the liquid to be sprayed into the vapor sufiiciently to vaporize some of the liquid before it is sprayed.

4. The method as set forth in claim 1 together with the step of preheating the liquid to be sprayed by transferring to it from the confined current of superheater vapor sufficient heat to vaporize a portion of the liquid is;

forth in claim 1 tobetween said two sets of superheating elements and having means adapted to create a spray, and means for introducing water into said 0011 at a rate increasing with increasing temperature at the outlet of said secondary superheating means said preheating coil be ing adapted to normally heat the water so that it substantially all vaporizes before reaching the inlets of the secondary set of superheater elements.

WILBUR n 'aniuaoos'r.

and projects into the stream of superheated I I The thermostat 58 is of the type which employs a volatile liquid, the ex pension and contraction of which in response to changes in temperature is ut lized by suitable connections such'as the flexible pipe 60 to control the position of the valve 56 so as to increase the flow of liquid through the valve with increasing temperature of the

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