US1604779A - Desuperheater - Google Patents

Description

J. R. M DERMET DESUPERHEATER Original Filed Jlily 15. 1923 INVENTOR Patented Oct. 26,

' UNITED. STATES PATENT oFFI I JonNn. mnnannr, or JEhNNn'rrE, rENNsYLvANm, AssieNon' 'ro ELLIOTT COM- I IPA/NY, or rxr'rsnonon, rnNNsxnvaNma CORPORATION or PENNSYLVANIA.

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original application filed July 13, 1923, Serial No. 651,301, Divided and this application filed May 14,

1926. Serial No. 109,050.

The present invention relates broadlyto power plant equipment, and more "particu- -larly to an apparatus for desuperheating; steam. In accordance with this invention,

the superheated steam is treated, whereby it is adapted for heating purposes.

With the increase of steam pressures charged from the gland seals of large tur-- bines, this steam having been used for sealing purposes and throttled from the condition of initial high superheat and pressure to approximately atmospheric conditions.

As a matter of technical fact, the superheated steam has only about one-thirtieth the conductivity of saturated steam from the standpoint of heater performance. It is well known that the major transfer of heat in heater condensation is from the latent heat of the steam in condensing. In the case of superheated steam, therefore, it is necessary to first destroy the superheat and reduce the steam to a condition of saturation before the latent heat is available.

that the specific heat of saturated steam is approximately .46 B. t. u. per pound, while the latent heat is substantially 970 B. t. u. per pound under the usual conditions of operation. V

In the average closed feed water heater, the superheat is destroyed to some extent by the condensation which ultimately forms on' h comes readily apparent when it is considered ers. necessary to provide sufiicient. surface within the heater and such conditions .as to permit the condensate which ultimately forms in the heater, due to the removal of heat, to act as a desuperheating medium.

Fromthe foregoing, it becomes apparent that muchmore efiective results could be obtained if it were possible to desuperheat the steam before its passage to the heater, and thereby render the latent heat available for use.

The present invention relates to such a desu'perheating and provides means 'for efficiently roducing the results desired by reducing t e superheated steam to a saturated condition by intimately mixing water therewith. Inthis process, an amount of water equivalent to the superheat of the steam is sufficiently atomizing the water to intimately mingle it withthe steam, and still retain it within the body of the desuperheater. It is not efiicient, in general, to allow water from the desuperheater to flow over into' the heater, as water, it being desirable that it 0 over as saturated vapor. I have also found that heat transfer takes place more readily from steam to metal when the metalis covered with water than from .a spray as referred to. This is probably due to the increased time limit in which the water and (steam are in contact. The present invention, therefore, involves the treatment of the superheated steam under ideal conditions for the evaporation of the treating water and for the reduction of the superheated steam iif acondition of sa(t1urat1on. th

In e accompanying rawmgs' ere is shown for p oses-of illustration only a preferred embo ent of an apparatus for efiecting such desuperheatmg of steam, it being understood thatfligd ss do not define the limits of the inventioin-as changes ma obviously be made in the construction an operation disclosed without departlng ,from-the spirit of the invention or scope of the broader claims.

In the drawings Figure 1 is an endelevation of a portion of a desuperheater embodying the present ure i, superheated steam from any desired invention; and I Figure 2 is .a vertical sectional viewthrough; the apparatus illustrated 1n Fig In accordance with the present invention, source may be conducted to the desuperheater 'through an inlet 2. This inlet ,is in com= munication as clearly shown in Figure 2, withthe interiorof the desiiperheatmg chamber 3.; In order to pass through this chamber to the outlet 4, it is necessary for the steam t6 first pass through the bafie 5, the wire'mesh 6, and the baflie 7. These bafiles may advanta eously be constructed of perforated Mone metal and the wire mesh 6 therebetween may be of Monel spacer cloth loosely woven of interlocked Monel wire, althou h other materials may be used,

if desired. referably the .wire mesh is in the form of a ribbon of material having a width. substantially equal to the width of the chamber 3,,and adapted to be inserted struction, the baflle p mesh form, in effect, a, cartridge between the perforated p ates by permitting the same to fold over upon itself, as clearly indicated in the drawings. Due to this conates and the wire which can bebodily inserted in-or removed from the chamber 3. To'facilitate such insertion and 1 vided with a series of discharge outlets or removal, the chamber a removable head 8. M

Carried by the head 8 is .a water manifold 9, havin an. inlet connection 10 "leading to a suitabia source of water supply'and pro-' may be provided with nozzles 11 attending substantially across g the removable cartri slowly thereover, but anyexcess orated by the superheated steam. is dise tomof a desuperheater chamber.

These nozzles; distr1bute the water uniformly over the wire mesh, so that it runs charged through a suitable outlet in the bot- It will be apparent that the steamis effectively broken up an vbrought into iDtl-r mate contact with a large area of metal sur' face covered with water, thereby providing a very eflicient means'for reduoingisuperheat- 'trid e an ed steam to a condition of/s'aturation. The steamincreased in quantity due to the 'evap-' oration of the water sup 'ed for desuperheating, but containing-t e,same' heat con- -tent under the same pressure conditions, then "Passes through the outlet a suitable heater; not shown.

connectign 1, to

PP ratus provides for a transfer ofheat partnot -evap- -1t is inevitable that some scale may'form on the -desuperheater element. Normally the extreme temperature ranges which the a paratus encounters will detach this sea e from the wire mesh by the difference in expension between the scale and wire. The

preserit;Iconstruction, however, makes it po sto; efictlvely remove any remafihng' sible scale periodically as may be desired, by

simply 'removin the c'artrid e bodil and. r g y shaking theeham or tape of wire mesh. 7

then Thereafter ,the mesh may be again lapped or folded into position a d. the cartridge inserted in ,the des'uperheiker chamber.

a It will bfapparent to'those skilled in the art that the balflesprovide interstitial tor tuoua-flow passe es located irregularly and at' 1 fandom. .Suc a construction is effective through capillary action for holding" the water-against bodjly'removal by the steam.

Inasmuch. as it isg'u'ndesirable to'carry :any

free watenal'ong 'with.--the steam, the apparatus is prefera ly'desi'gned to. 've arela- It willbe apparent that in the process. euaporation of water in the desuperheater,

tivelylow,steam velocity throng the inte'ra stitial passages, and to this end .the combined "area of thesefpassages is at least substaitially as great asg the area of .the inlet an decrease in flow; velocit The present application constitutes afldivision of my co-pndingapplication Serial No. 651,301 filed July. 13, 1923.

preferably greater to thereby insure a Certain advantages of the present inven-- tion arise from the provision ofa desuperheater embodying a 'porous body or a body pervious to the passa e offisteam, together with means for supp ying' water in such mannex that an eflicient contact between the 7 water and steam is insured.

Other advanta es-arise from the provision of, means for e ectively b ging thede- 'superheating water into -con act with superheated steam in such. manner that the superheated steam -is reduced apondition of saturation. p

Further advantages arise from the construction ermitting the removal ofthe' cardesired. 1

Still-'other-advantages arise from the interstitialflow passages efiective not only for insuring intima contact-between thesteam and'water, but also for holding the water figginpt removal by the steam.

- ana pparatus, for treating;

cleaning of: the parts as may be,

neonate heated steam, a desuperheating chamber,

means for delivering superheated steam and water to said chamber, and means in said chamber and intersecting the steam flow for bringing the steam and water into intimate contact, said means having a plurality of interstitial flow spaces therethrough.

2. In apparatus for treating superheated .steann/ a desuperheating chamber, means for delivering superheated steam and water ,to said chamber, and means in said chamber having irregular flow passages therethrough for bringing the steam and water into intimate contact.

3. In apparatus for treating superheated steam, a desuperheating chamber, means.

for delivering superheated steam and water to said chamber, and means in said chamber having irregular flow passages therethrough for bringing the steam and water into intimate contact, said means being bodily removable for cleaning purposes.

4. In a paratus for treatingsuperheated steam, a esuperheating chamber, means for delivering superheated steam and water to said chamber, and a wire mesh in said chamber for bringing the steam and water into intimate contact. i

5 In apparatus for treating steam, a flow conduit for the steam, and means efiective for exerting a capillary action on water extending transversely of said flow passage.

'6. In apparatus for treating superheated steam, conducting means for the steam, a body of wire mesh located in the path of travel "of the steam, and means for supplying water to said wire mesh;

7 In apparatus for treating superheated steam, conducting means for the steam, and

steam, conducting mea.ns for theflsteam, a-

perforated plate in the-path of travel of the steam, and a water covered body cooperating with said plate and having tortuous :dow'pas sages for the steam. v

10. Apparatus for treating superheated steam, comprising in combination with a conduit for superheated steam, a battle extending across said conduit and having tortuous passages therethrough, and means for supplying Water to said battle, the combined area of the tortuous passages being such relatively to the cross-section of the conduit as to vary the velocity of the superheated steam as it passes through the Wetted path.

11. Apparatus for treating superheated steam, comprising in combination with a conduit -i or superheated steam, a baliie ex-' tending across said conduit and having tortuous passages therethrough, and means for supplying water to saidbatlie, the combined area of the tortuous passages being such relatively to the cross-section of the conduit as to vary the velocity of the superheated steam as it passes through the wetted path, said bafiiecomprising a mass of heat resistant material providing interstices therebetween.

12; Apparatus for regulating the temperature of superheated steam, comprising in combination; with a conduit for superheated steam, a bafie extending across said conduit and having tortuous passages therethrough, and means for spraying water upon said bafiie, the combined area of the tortuous pasv sages differing from the cross-sectionof the conduit, whereby the velocity of the superheated steam is varied as it passes through the Wetted bafie.

13. Apparatus for regulating the tomperature of superheated steam, comprising in. combination with a conduit for super,- heated steam, a battle extending across said conduit and having tortuous passages therethrough, and means for spraying water upon said bafiie, the combined area of the tortuous passages diife'ring from the cross-section of the conduit, whereby the Velocity of the 'su-.

perheated steam is varied as it passes through the wetted baflle, said wetted baifle "comprising" a mass of heat resistant material providing interstices therebetween.

In testimony whereof I have hereunto set my hand. I

,6 Jorni n. MCDERMET.

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