US1688132A

US1688132A - Desuperheater control

Info

Publication number: US1688132A
Application number: US158590A
Authority: US
Inventors: Joseph M Barrett
Original assignee: SWARTWOUT CO
Current assignee: SWARTWOUT CO
Priority date: 1927-01-03
Filing date: 1927-01-03
Publication date: 1928-10-16
Anticipated expiration: 1945-10-16

Description

J. M. BARRETT DESUPERHEATER CONTROL Oct. 16, 1928.

Filed Jan. 5, 1927 Patented Oct. 16, 1928.

UNITED STATES ATENT oer-ice.

JOSEPH a. masses, or rosronm. onto, reassessment swati'rwour ooivrrhivir, OF CLEVELAND, OHIO, A CORPORATION or 01110.

'DEsuPERHEATsR censor.

Application med January 3, 192 Serial No.'158, 590.

This invention relates to desuperheatii'ig and is particularly concerned with 'thecontroloi. the change in quality of steam by reason of the flow of water to the desup'erheater. p

It frequently happens in steam power plants that the steam delivered from the boiler or boilers is superheated several hundredrlegrees' It also happens that it is desired to use only saturated steam or at least steam that is but slightly superheated, for the auxiliary apparatus or for carrying out certain processes where thesuperheatis disadyantag'eou's or even harmful. I

' The method of desuperhcating steam, shown in the disclosure herewith comprises spraying comparatively cold water under high pressure into a chamber through which the steam passes. The superheated steam picks up the moisture, vaporizes it and delivers substantially saturated steam. The

quality or tlierelative amount of superheat in the steam delivered from the chamber depends upon the rate of flow of water into the chamber.

The design of a given desuperheater estab lishes certaiirconstant factors but, for the purpose of showing my invention, I presume that the spraying and bathing apparatus'in the chan'lber is such that for steam of a given degree oi superheat, if water is trapped at a certainrate immediately below the chamber that substantially saturated steam will be delivered. I V

It is among the objects of my invention to control the low of water into the desuperheater so that acertain amount of water will be inaintaii'ied in a container or receiver dis-' posed below the chamber and in free communication therewith. By so doing, predetermined amount of water is addedto the superheated steam so that saturated steam is delivered. The amount of water then held in the, container below the desuperheating chamber is a measure of the quality oi the steam deliveredi It will be seen that if the inflow of water is stopped, that the superheated steam will pick up all the water with which it comes in contact so that both the .desuperheating chamber and the ad jacent container or receiver will be quickly dried. i

To accomplish the objects of myinvcntion, I control the flow of water into the desuperheater with relation to the amount of water maintained in the receiver iimnediate'ly below the chamber and thereby 'ac "complishing the result of delivering substantially saturated steam. As the demand for saturated steam varies, the inflow 0t superheated steam will vary accordingly, therefore, it is necessary toproportion the inflow ofwater to the desuperheater so that a certain'quality of delivered steam may be maintained. I am able to accomplish this result by controlling the inflow of water into t-l1edesuperl1eater by using as a-m'e'astu'e'lthe amount or" water in the receiver disposed below the chamber. V v

If by reason of the primary demandon the boiler, the degree of s'u perheat varies, and I desire to deliver steam of the same quality from the desuperheater, I find that by controlling the inflow of water with relation to the amount of water'h'eld in the con tainer below the chamber, that I may compensate for varying degrees of superheat as Well as for demand for saturated steam.

.Thus I am able by very simple installation to accurately and constantly control the input of water so that steam: of a certain predetermined quality will always'be delivered regardless of the degree of superheator the demand for saturated steam. I

j Other objects will become apparent from the following more detailed (ilescriptioh of the apparatus employed in my invention, a preferred form of which is shown in the drawings. The essential characteristics are summarized in the claims.

In the drawings Fig. 1 is an elevation water. inlet at 10, I show diaphragm closed by the spring 11 and which is forced to open position as a result of pressure eX- erted on the diaphragm 12 through the conduit 15 by means presently to be described.

As mentioned above, a container. or receiver 40 is disposed immediately below the desuperheater 1 in free communication therewith through the shor"u connection a1, a gauge glass may be used as at 42 to show the water level LL in the receiver 40. A suitable blow-oft valve 13 may be connected to the bottom of the receiverso that an occasional collection of sludge or mud may be blown down.

Disposed to intersect the plane of the water level of the receiver, I show a pressure generator 20, having radiating finsr18- and a filing plug 19 This generator may be of general type shown in the patent to Copley No. 1,193,125 issued August 1, 1916.

The generator is mounted on a conduitw iich The generator is connected at its lowermost point with the pressure conduit 15 mentioned above which leads to the diaphragm chamber of the valve 10. It will be seen therefore, that when the water level in the receiver rises that the generator will be chilled and the pressure in the conduit 15 and on the-diaphragm l2 reduced so that the valve 10 will be forced to a closed position. On the other hand, when the water level in the receiver falls, the steam will move downwardly adjacent the generator thus building up the presure of the working fluid therein, which will tend to open the valve lOto permit a greater inflow of water so that a substantially even Water level is maintained with theresult that the proper amount of water is introduced to the superheated, steam so that saturated steam will be delivered.

To efi ect the operation of the pressure 7 generator, I provide the .conduit 21 which I show connected at its upper extremity through the valve 22 to the superheated steam inlet pipe at the point '23. I find 1t advantageous to connect the conduit 21 either. tov the superheatedsteam inlet or the saturated steam outlet rather than any part of the desuperheater or the receiver because vofthe preseneeof water or'mist in the last named chambers. It is however, possible butnot so practical,to connect the upper portion ofthe conduit 21 to the de superheater with a suitable. trap .connec tion so that the steam in this portion of the conduit 21 is substantially dry. The conduit point 30, and by reason of the

connections

24,25 and 26, the angular position of the generator may be varied. It will be seen that the rapidity of reaction of the generator is a function of its angular position.

Associated withthe portion 32 of the conduit' 21, which portion is immediately below the generator, I provide a radiator or cooler 33. This radiator also serves as a cold water reservoir. The cooler may for the sake of convenience, be of a construction similar to the generator proper (see Fig. 3), but the connection with the portion 32 of the conduit is such that water may flow through the whole cooler having. an opportunity to pass through the chamber adjacent the heat radiating fins 3 L as shown. A plug 32' is put in the conduit; perforations 35 are provided; A suitable blow-down valve 36 is connected to the lowermost portion of the conduit 21 so that the contents of the conduit may be blown out when desired. It is adwhich will tend to open the valve 10 and let water flow into the'desuperheater. If the valve is forced wide open by reasonof high pressure being exerted, a surplus of water will collect in. the receiver 40 so that the water level in the receiver will rise -.until that portion of the conduit 21 within the generator contains water'o'l a low heat con tent which will tend to chill the generator and throttle the valve 10 sothat the inflow of water is balanced against the demand therefor.

. Particularly in starting, it isfound that the water. collecting in the receiver is very hot in that the generator may be very slow to respond to a rapidly rising water level. By the use of the radiator'or cooler 33 I am able to chill all of the water. which moves upwardly into contact with the generator so that the temperature difference may be sharp and the action of the generator well defined;

The drop leg construction including the

portions

31 and 32 of the conduit 21 along with the cooler 33, provides for the maintenance of a reservoirof cold water even in the event that all the water in the. receiver is taken up. It will be seen that I. gain added advantages by using both the'drop leg and cooler. I

From the foregoing it. will appear that I have provided a simple and rugged control for a desuperheater, that my device can be oper d advantageously on high pressure tions and that the wearing and WOIliing )2 ts are very few, and thatthe operation constant and positive; The quality of the steam delivered may be controlledby reason of the compensation effected both :for

the degree of superheat and for the demand for saturated steam,

I claim: p

1. The method of controlling the flow of water to a desuperheater dependent upon the rate of accumulation of water collected 3. In combination, a desuperheater, a rcceiver disposed below the -desuperheater and in open communication therewith but protected from the flow of steam through the desuperheater and means controlling the flow of water into the desuperheater depen dent upon the water level. in the receiver.

4.. The combination witha desuperheater, a receiver disposed below the desuperheater, means for controlling the flow of water to the desuperheater according to the water level in the said receiver, said means includinn; thermo-responsive means disposed at the water level of the receiver.

5. In combination, a desuperheater having an inlet for superheated steam, an outlet for saturated steam, a Water pipe for delivering water to the desuperheater, a valve in said pipe, a receiver positioned below the desuperheater adaptedito contain an excess of water delivered to the said desuperheat-er, and thermo-responsive means responsive to change of water level in the receiver for actuating said'valve. V

6. In combination, a desuperheater having an inlet for superheated steam, an outlet'for saturated steam, a water pipe for delivering Water to the desuperheater, a valve in said pipe, means for maintaining an excess of water in the presence of the steam, and thermo-responsive means respon- V sive to change in the amount of said excess water for actuating the valve in said Water inlet pipe.

7 In combination, a desujperheater liavmg an inlet for superheated steam, an outlet tor saturated steam, a water pipe for delivering water to the desuperheater, a

pressure actuated valve in said pipe, a receiv'er positioned below the desuperheater r. .ited to contain anexccss of water delivered to the said, des-upcrheater, a conduit connected to said receiver and to said steam inlet and pressure generator means associated with said conduitresponsive to change of waterlevel in the receiver for, varying the opening ot'said valve.

eluding a mixing chamber having an inlet for superheated steam and an outlet for saturated steam, a water pipe leading to said desuperheater, a valve in said pipe, means comprising a separate chamber for maintaining below the desuperheater an excess of water in open contact with the steam, and means for varying the opening of said valve dependent upon the amount of said excess. 9. In combination, a desuperheater having an inlet for superheated steam and an out-- let for saturated steam, a water inlet pipe connected to the desuperheater, a pressure actuated valve in said pipe, a conduit disposed outside ofthe desuperheater and connected at its ends to different parts of the desuperheater, and pressure generator means associated with said conduit for controlling the opening of said valve.

10. The combination of a desuperheater having an inlet for superheated steam and an outlet for saturated steam, a Water inlet pipe for the desuperheateig a valve in said pipe, a receiver positioned below the desuperheater and in open communication therewith, and adapted to contain an excess of water delivered to the desuperheater, a conduit leading from a point in the receiver below the normal water level thereof, and to the steam inlet, pressure generator means associated with the conduit and positioned in the plane of the normal water level of the receiver, said conduit including a drop leg between the said pressure generator means and the receiver, radiating and cooling means associated with the conduit beloW said pressure generatonand fluid conducting means connecting the pressure generator with said valve whereby the valve is actuated in response to change in water level in said receiver.

11. The combination of a desuperheater having an inlet for superheated steam and an outlet for saturated steam, a water inlet pipe, a receiver positioned below the desuperheater and in open communication therewith and adapted to contain an excess of water delivered thereto, a conduit connected to the receiver below the normal water level thereof and to a part of the system containing 8. The combination ota desu'perheater inpipe for the desuperheater, a valvein said dry steam, pressure generator means associat'ed with the conduit and positioned in the plane of the normal water level of the receiver, said conduit including a drop leg between the said pressure generator means and the connection with the receiver, radiating and cooling means added to and associated with the drop leg portion adjacent said generator, and means connecting the pressure generator with said valve whereby the valve is actuated in response to change in Water level in said receiver.

12; The combination of a. desuperheater having an inlet for superheated steam and an outlet for saturated steam, a water inlet pipe for the desuperheater, a pressure actuated valve in said pipe, a receiver positioned below the desuperheater and in open communication therewith and adapted to contain an excess of water delivered to the desuperheater, a conduit spanning the normal water level of the receiver and connected to the inlet for superheated steam, pressure generator means responsive to change in heat content of the fluid 1n the conduit for actuating said valve and positioned in the plane of the normal water level of the receiver, said conduit including a drop leg portion below thesaid pressure generator quickly responsive to change in Water level in the receiver.

In testnnony whereof, I hereunto affix my signature.

JOSEPH M. BARRETT.