US1771699A

US1771699A - Superheat-regulating device

Info

Publication number: US1771699A
Application number: US33721A
Authority: US
Inventors: Vern E Alden
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1925-05-29
Filing date: 1925-05-29
Publication date: 1930-07-29
Anticipated expiration: 1947-07-29

Description

July 29, 1930. v, E, ALDE N 1,771,699

SUPERHEAT REGULAT ING DEVI CE Filed May 29, 1925 2 Sheets-Sheet 1 INVENTOR V01 6'. who

ATTORNEYS V. E. ALDEN SUPERHEAT REGULATING DEVICE July 29, 1930.

Filed May 29, 1925 2 Sheets-Sheet 2 INVENi'OR w QM,

AT TORN EYS Patented July 29, 19 30 UNITED S ATES PATENT VERN E. ALDEN, OF BALTIMORE, MARYLAND, ASSIGNOB TO THE BABCOQK & WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY SUPERHEAT-REGULATING Davida Application filed lllay 29,

My present invention relates to superheat ers provided with regulating devices by which which the degree of "superheat delivered fronf the superheater may be regulated. ,My invention willbe best understood from the following descriptipn and the annexed drawings, in which Fig. 1 is an outside view of a separately fired superheater, with some of the\ parts broken away and embodying an illustrative form of my invention; Fig.

2 is an enlarged view, with some of the parts broken away, of a portion of Fig. 1 and Fig.

3 is an enlarged view of a portion of Fig. 1.

Like reference characters indicate like.

In the illustrative arrangement, I have shown a separately fired superheater having a casing 10 andbanks of tubes 11, the tubes of these banks being inverted U-tubes connected to the lower drums 12 with a steam inlet pi e 13 connected to the rear-most drum 12 and t e front bank of tubes 11 being connected to a superheater outlet pipe 14. The superheater is fired, in the illustrative form by an underditions in a power plant will vary from time feed stoker 15 and the casing 10 may also be 7 provided with a steam generating apparatus in the form of a water tube boiler, the drum, 16 indicating 'a portion of such a separate steam generating apparatus. Since such an apparatus, however, may be used or not, as desired, and is no part of my present invention, further description thereof will be unnecessary. The superheater which I have shown, is of a'well known type, but I have shown it merel for purpose of illustration, since the speci 0 form of superheater is no part of my present invention. It will be understood that in the form of superheater illustrated, steam from one or more steam generators or from intermediate stages of asteam turbine 01-, any other source,

flows through the inlet pipe 13 and from thencethrough the tubes 11 and the drums 12 to the superheater outlet 14, such steam,wh1'ch may be saturated steamwhen it enters the superheater, being raised to a high degree of superheat in its passage through the superheater.

As is well understood, the operating con- 1925. Serial No. 38,721.

to time, so that without provision to that end,

OFFICE the superheat in the steam delivered through the pipe 14 will vary considerably, and this will cause serious operating difficulties, particularly if, as is usually the case, it Is desired to maintain the superheat at as high a point as may be without exceeding a predetermined limit which would cause operating difiiculties.

It has heretofore been proposed to regulate the superheat by injectin water into the steam after it has passed the superheater. This, however, presents a number of difiiculties. For instance, where the superheated steam is supplied to turbines, it is particularly desirable'that no Water shall enter the turbines. When water is injected into the superheated steam between the superheater and that some water will pass into the turbine. This difilculty has heretofore been controlled largely by spraying the water into the Steam, but obviously the maintenance of these sprays and the insurance that the spray will be fine enough to make certain the evaporation of all of the water adds to the operating difliculties.

In in present arrangement, I overcome these dlfliculties by admitting water to the steam entering the superheater in accordance with the operating conditions, so that the de gree of superheat in thesteam leaving the superheater can be maintained substantially constant. Furthermore, it will be obvious that by thus introducingthe-water, its evaporation will be insured as it is carried through the superheater, so that fine spraying of the water will not be necessary.

Preferably, I arranged my apparatus ,so

that the amount ofwater admitted to the steam at the inlet sideof' the superheater will be in accordance with the temperature of the steam at the superheater outlet. In other words, if the superheat in the outlet tends to rise, thanI admit water into the inlet side, and if the quantity thus admitted is not sulficient to bring the superheat down to the de sired int, then a greater rate of flow of water 1s set up in the inlet side until the additional quantity of'water to be evaporated in the superheater will bring the degree oferator will be guided in such admission.

Preferably, however, I provide an automatic means for admitting the Water to be controlled by devices ldcated in the superheater outlet, so that the quantity of water admitted will be automatically determined by the conditions in this outlet.

As an illustrative form of such automatic arrangement, I have shown an apparatus which is described more in detailin the copending application of David S. J acobus, Serial No. 7 48,885, filed November 10, 1924, but it will beunderstood that any other form of temperature controlled apparatus may be used for this automatic control.

In the arrangement described, a valve body 17 is provided with a plurality of ports 18,

each having a valve 19 cooperating therewith, this valve body 17 being located in a .water supply pipe 20 having its outlet 21 entering the upper part of a vertical portion 22 of the superheater inlet pipe this pipe preferably being provided with a long bend between the vertical portion and the superheater drum 12.

The pipe 20 may be provided with a number of small openingsin its lower portion so that water passing through the pipe 20 will fall downward in the vertical section 22.

- With my arrangement, however, it will be un-' necessary to attempt to spray this water into fine drops.

In the vertical section 22 I have provided a ,pluralit of water spreading devices in the form 0 screens held between the sections of the pipe, these screens serving to receive the 4 water from the pipe 20 and spread it over a vice may be widely varied, the form shown hebetween which is wire screen secti0ns, 23 eld a mass 24' of small bodies which may be of any desired material. It will be understood that if the screening effect is not desired, then the water may caused to flow down over any extended surfaces positioned inthe pipe so as to contacted by the inflowin steam.

The valves 19 may operated independently and it will be obvious that in the arrangement of the valve body 17, as defined in ing a pair of hea Fig. 2, the amount of-water which will flow rangement'is no part of my present invention,

from right to left through the valve body These screens also will be determined by the number of valves 19 which are opened. While these valves 19 may be operated by hand, I prefer to operate them automatically, and in the arrangement shown, each valve 19 has a stem 25, to which is attached a soft iron core 26 moving in a solenoid 27. The valves are normally held closed by a spring 28, the height of the lift of the valves being controlled by the contact between the top of the core 26 and the bottom of a hollow body 30 surrounding the upper end of the stem 25 and whose position is controlled by a screw 29 connected to some fixed part.

tacle 31 containing an expansible fluid which In the superheater outlet pipe 14 is a recep is connected through a pipe 32 to a vertical tube 33, in the Walls of which are inserted electric contact points, the tube 33 being filled with mercury, the height of which, of course, will be determined by the temperature of the receptacle 31, which, in turn will be determined by the temperature of the steam leaving the superheater. There may be as many of-the contacts as desired, each being in ir cuit with one of the solenoids 27 and asource of energy. It will besuificient to describe one of these circuits, the contact member 34 of which is connectedthrough the wire 35 with one of the solenoids 27, the other side of the solenoid being connected through the wire 36 with the wire 37, the battery 38, the wire 39 and a contact point 4Q at the bottom of the tube 33. 1 As the temperature of the steam in the outlet rises, the mercury column in the tube 33 will also rise and when it reaches the contact 34, a circuit is formed between the

contacts

40 and 34 and the wiring connected thereto to open the valve connected with the solenoid 27 in that circuit.

It will be understood that in the illustrative form, the mercury in rising to the contact 34 will have successively risen to the lower contacts and will have therefore successively opened the valves 19 in circuit therewith, so

that, in the illustrative form, when the mercury reaches the contact 34, all of the valves will have been opened. 1

Obviously, similarly, as the temperature in the superheated steam begins to dro' the mercury in the tube 33 will also drop an thus the valves 19 willbe closed one at a timeIto shut off the water until the desired balance is reached.

In order to prevent disaster through failure of the water supplied through the pipe-21 to i keep the superheat within the desired limits,

in the arrangement shown, there is a contact 40' atthevupper part of the tube 33' which, when the mercury reaches it, closes a circuit through. an operating device'for a water ops erated motor 41 to open doors 42 in the setting to permit air to pass directlyinto the setting to cool the superheater tubes '11. Such arand further description thereof will be un- ,1. In a superheat regulating device, a'

superheater, an inlet pipe therefor, means to admit water into said inlet pipe, and water spreading devices in said inlet pipe between t e superheater and the point of admission of the water, whereby the water is spread over surfaces contacted by the steam beforev entering the superheater.

admit water into said inlet superheater, an inlet 2. In a superheat regulating device, a superheater, an inlet pipe therefor, means to (pipe, said pipe having a vertical portion, an water spreading devices in sai vertical portion between the superheater and the point of admission of the water, whereby the water is spread ,over surfaces contacted by the steam before entering the superheater.

I 3. In a superheat regulating device, 'a i e therefor, means to admit water into sai inlet pipe, said pipe having a vertical portion into the upper part of which the water is admitted, and water spreading devices in said vertical portion and positioned to receive the water so admitted and to be contacted by the steam flowing to said superheatera 4. In a superheat regulating device, a superheater, an inlet pipe therefor, means to admit water into sai inlet pipe, said pipe having a vertical portion into the upper part of which the water is admitted, and ascreen in said vertical portion and positioned to receive the water so admitted and adapted to permit the steam flowing to said superheater to flow therethrough.

5. In asuperheat regulating device, a superheater, an inlet pipe therefor, means to admit water into said inlet pipe in relatively large masses, and water spreading devices in said. inlet pipe between the; sup ,erheater and the point of admissionf'of the water to spread such masses over an extended surface contacted by-the steam flowing to the superheater.

6. In a superheat regulating device, a superheater, an inlet pipe therefor, means to admit water into said inlet pipe in relatively large masses, said pipe having a vertical portion, and a screen in said vertical portion beneath the point of admission of the masses of water and positioned to receive the same and to permit e steam flowing to the superheater to pass through the same and contact with the water therein.

7. In a superheat regulatin device, a superheater having an inlet an an outlet,

I means to admit water into said inlet comprising a water delivery pipe, a water supply pipe and amultiple-ported valve'body connecting the two pipes, each port having a separately-openable valve therefor, means for opening said valves successively.

8. Ina su erheat regulating device for a superheater aving an inlet and an outlet,

means to admit water into said inlet, compris-- ing a waterdelivery pipe, a water supply pipe and a multiple-ported valve body connecting the two pipes, each port having a separately-openab e valve therefor, a thermostat in said outlet and means operated by said thermostat to open successively said valves as the temperature of the superheated steam at said outletincreases.

9. In a su erheat regulating device for a superheater aving an inlet and an outlet, means to admit water,into said inlet, comprising a water'delivery pipe, a water supply pipe and a multiple-ported valve body connecting the two pipes, each port having a separately-openab e valve therefor, (and a thermostat in said outlet, solenoids to open each of said valves, and electric circuits each containing one of said solenoids and arranged to be energized successively by said thermostat.

10. In a su erheat regulating devicefor asuperheater aving an inlet and an outlet, means to admit water to said inlet, a thermostat in. said outlet, electric circuits for operating successively water-admitting means and controlled by said thermostat, whereby the quantity of water admitted is increased and as said electric circuits are successively oper-' ated.

11. In a superheat regulatin device, a superheater havin an inlet an a pipe adapted to ischarge water into said inlet, a plurality of valvescontrolling the discharge of said water and means to operate the valves successively upon changes in the heat of the steam in said outlet.

YERN E. ALDEN.

*no an outlet.