US1405821A

US1405821A - Condensing apparatus

Info

Publication number: US1405821A
Application number: US261708A
Authority: US
Inventors: Raymond N Ehrhart
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1918-11-08
Filing date: 1918-11-08
Publication date: 1922-02-07
Anticipated expiration: 1939-02-07

Description

\ I I Y A 11v ENTOR. WITNESSES: I j 5:

. I BY A R. N. EHRHART.

CONDENSING APPARATUS APPLICATION FILED NOV-8,1918.

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ATTORNEY].

the fluids within the condenser.

' uulrso STA ES PATEL-NT oFFlC-E.

RAYMOND REHRHAM, or EncEwoon, PENNSYLVANIA, ,ASSIGNOB. ro WESTING- HOUSE ELECTRIC a MANUFACTURING COMPANY,'A'GOBPORATIO1 \T or mm,

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CONDENSLN'G AIPARATUS. I

. To all ablwm'z't may concern:-" I

Be it known that I, RAYMOND N. EHR- HART, a citizen of the United States,-and a resident ofEdgewood, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Condensing Apparatus, of which the following is a specification his invention relates to -condbnsing ap-, paratu's and particularly to air,extracti ng' apparatus for condensers.

Condensers employed for condensing steam exhausted ir0m power developing units are usually provided wlth'means for extracting non-condensable fluids, such as air from the condenser.- .The degree. of

vacuum obtainable within a condenser is in a large measure dependent upon the air (that is, non-condensable fluid) content of If no'air were present. within the condenser the vacuum would absolutely correspond to the temperature of the condensate, or in other 'words, the pressure within the, condenser would correspond to the theoretical vaporizing pressure of'the condensate at the'tem perature of the condensate'wlthin the-condenser. A slight amount of air within the condenser materially varies the, pressure it is essential to so design the air extracting apparatus that it will be capable of extractall the air entering the condenser un-' 'dersubstantially normal operating con'-- conditions, with relation to condensatetemperatures, and. consequently reduces the efliciency -of the condenser. For this reason ing ditions. In this. connection attention is called to the fact that the word air is herein employed to include all vapors under conditions obtaining withinthec'onor fluid which may enter the condenser and which are not capable of being-condensed denser. Where the air extractingapparatus v capacityconditions, there is somelo's's occasioned by the fact that the power consumpadmisslon to'the ejector apparatus is contion ofthe air extracting apparatus is not commensurate with variations in the amount of air to be withdrawn. Steam actuated air ejectors are sometimes-employed as the, air extracting apparatus for .condensers,f:pri-' "marily because they .are simple in construction; and operation. It is a characteristic of such ejectors that they are efficient only Applicationfiled November 8-,; 1918. Serial No. 261,708

for'which they are designed. When the load -w'hen operating under the load conditions is light, that is, when there is only asmall quantityof air to be ejected, substantially the,v samequantity of motive steam must be supplled to the ejector as when the ejector is working atfull load capacity,-in order to preven, upsetting of the ejector, that is,

momentary equalizations' of pressure between theinlet and exhaust of the ejector.

In my co-p'ending application for patent, entitled Ejector apparatus, filed August 21, 1918, Serial No. 250,899, ,I have disclosed a plurality of ejectors connected in parallel with the condenser and so arrangedithat motive fluid may be supplied to one or more of the ejectors inresponse-to the. operation of a controlling device which is responsive to the quantity of air to beextracted from the condenser. With such an arrangement, each ejector can be of proportionately in order to prevent momentary back flows or smaller capacity according to-the number installed, so that when they are all in operation their combined capacity is ample to efliciently withdraw the maximum amount of air-encountered under-normal operating conditions. Therefore if the 'ambuntof air v to be extracted is small, one ejector. opei' ating at maximumcapacity and consequently with high efficiency-is in operation, and,.

consumedin their operation is proportional to the work done, while inthe case of a single ejector, a suflicient quantity of steam .the others" are successively brought into operation asthe quantityof air. to be removed increases. For this reason the steam plurality. of the ejeetors, similar to those 1 disclosed in the above noted (do-pending application are employed, and this invention has'for a broad object toroduoe agcondenser apparatus wherein the motive fluid trolled 'bymechanism responsive to Vania fluid within the condenser-.1-

- Another object of the invention is a; produce means for control1ing tlie1admission of motive fluid to the ejector apparatusinrespouse to relative variations i i-temperature" between the steam entering and the condensate leaving the condenser.

Another object is to produce thermostatic means for controlling the motive fluid admission to the ejector apparatus responsiveto relative variations in temperature between the fluid entering the condenser and the condensate leaving the condenser which may be adjusted to compensate for the differences in operating conditions occasioned by external changes of temperature incident to the changes in the seasons.

I A serious air'leak or insufficient extraction of air by the air extracting apparatus, occasions a relatively greater difference in the temperature ofithe incoming steam and the condensate collected withinand delivered by the condenser than is the case where the air content of the fluids within the condenser is normally low. The condensate temperature will be less than the theoretical temperature corresponding to the pressure within the condenser, 'and considerably less than the 'temperature of the, incoming steam. Where other conditions are maintained constant the difference in temperatures between the in-, comin steam and the outgoing condensate shoul also remain constant for each individual condenser and a variation in this 80 determined temperature difference will 'in-' dicate air leakage or insufficient air pump capacity. My present invention therefore contemplates controlling the ejector apparatus in response to variations in this tem- 85 perature difference so as to maintain the air.

' more nearly the absolute vacuum, and air entering a condenser operating under wlnter' conditions will occasion a greater difference between the temperature ofthe condensate and the incoming steam than the same quan 65 tity of air entering the same con'denserop- 10" controllmg the supply of motive fluid to the ejectors 8, 9 and 10 respectively may crating under summer conditions. This wide variation in operating conditions may be compensated for by the adjusting means to which I have referred. One embodiment of the invention is dis.- closed in the accompanying drawing, where- 1n The figure is a diagrammatic illustration of condensing apparatus. embodying the invention, portions of the apparatus being conduit '11.

water-temperature, will affect the 'shown in section for convenience of illusthe surface type and is provided with a nest of cooling tubes 3, through which cooling or I condensing water is circulated. The condensate resulting from the condensation of the steam falls to the bottom of the con- -tlenser and flows into a hot .well 4, from which it is extracted by a centrifugal pump 5 and is discharged through the passage 6,.

to a feed tank shown. v I

The condenser is provided with an air outlet 7 ,,which communicates with a plurality of jet ejectors, 8, 9 and lO, by means of the The ejectors 8, 9 andMl-O are connected in parallel with the conduit or manifold 11 and are adapted to be operated or feed water heater, not

on motive steam suppliedto the header 12 from which steam flows to, the ejectors 8,9 and 10' throu h branch conduits 8, 9' and 10' respective y. These conduits 8', 9' and 10 are respectively provided with. controlling valves 8, 9" and 10" which may be preferably ofthe quick opening and closing type. As shown, valves 8", 9" and 10" are each provided with an operating lever 8, 9 and 10 respectively,,by which the valves may be operated by mechanism to be-hereinafter described. f The ejectors 8, 9 and 10 exhaust into common manifold conduit 13 which communicates preferably with a feed tank or feed b water heater, not shown. a A check valve 14' is located between the discharge port of each ejectorand the manifold 13 and is adapted to close and prevent the passage of fluid from the exhaust manifold 13 "back through the ejector passages when the steam supply to the ejector is shut off. As illustrated in 'the figure, the check valves of the ejectors 9 and lo are' closed and so are the control valves 9." and 10", while the valve 8 is shown open as indicated by the oblique position of the valve lever 8. The check valve 14 of'the ejector 8 is also shown in the open position where it is being held by the passage of fluid through the exhaust pasage of the ejector 8.

.It is the purpose of this invention to provide means whereby the valves 8', -9'( and a mechanism whereby this operation may be brought about in response to variations in the quantity of air within the condenser g and a resulting variation-in the relative dif ferences in temperature between the steam enterlng and condensate leaving the condenser.

' The above results are obtained in the illus trated embodiment of the invention bv means of a thermostatic apparatus includ-' ing a, pair of expansion members, 15 and 16, each comprising a metal tube made prefera'bly of brass or some other metal having a high coefficient of expansion. These tubes are anchored solidly in a baseblock 17, mounted upon any suitable foundation or support and are pivotallyconnected, at their free ends, to a rocking lever or beam 18. The upper or free end of the beam 18 is pivotally connected at 20, to a'valve operating bar 21, which is provided with an adjusting nut 22; whereby the length of the bar 21 may be adjusted to compensate for variations infoperating conditions; for example, wide variations in condensing water temperature The bar 21 is provided with a plurality of pins 23,- 24 and 25, one for the thermostat is in the each valve lever '8 9*" and 10 respectively, and the length of the bar 21 may be adjusted by means of the adjusting nut so that when normally assume when the quantity of air in the condenser is reducedto the practical operating minimum, the. pin 23 will be in operative engagement with the valve lever 8, so as to hold the valve 8" in open position as indicated in the drawing.

The thermostat tube 15 is subjected to the heat ofthe steam entering the condenser 1. This is accomplished by providing the-tubes 26,-and 27, the former connecting the upper. end of the thermostat tube 15 with the in-.

terior of the'condenser at a point immediately adjacent the inlet thereof, and the latter connecting the lower end of the thei'- mostat tube 15 with the interior of the con- 7 denser. at some point. near the region'of complete condensation as, for example, below the bafile wall 28- andabove'the normal level.

of the condensate. Under such conditions a'circulation of steam will be set up, passing from the condenser inlet 2 through the tube 26, through the thermostat tube 15, and into the interior of. the condenser through the.

passage 27, thus continually subjecting the thermostat tube 15 to the heat of the inheat of the condensate leaving the condenser,- by causing a portion of the condensate tocoming steam which will cause the length of the thermostat tube 15 to vary in respop'se' to variations in the temperature of the 1ncoming steam.- a The thermostat tube 16 is subjected to the pass through the tube. 'As shown the lower end of the tube 16 is connected to the condensatedischarge conduit 6, by means of a conduit 29 and the condensate is discharged from the tube through va conduit 30, which may communicate with the feed tank or water heater. Under such conditions the osition it would length of thetube 16 will vary by expansion an contraction in response to the variations in temperature ofthe condensate leaving the condenser.

' As the tube '15'is responsiveto variations in the temperature of the steam entering the condenser, and as the tube 16 is responsive. to variations in temperature of the condensate in the condenser, it will-be evident that any variations in the relative differencesin temperature between the two fluids, will result in a movement of the rocking beam 18, due to variations in length of the thermostat tubes. p I

Assuming that the temperature of the condensate is more or less uniform, its ulti-- mate temperature depending, of course, upon .the temperature of the cooling water circulate'd through the condenser, it will be seen that the rocking beam "18 will be swung clockwise by the" thermostat upon an in-- crease in the existing temperature of the steam entering the condenser. Any 'accumu lation of air, due to leakage or insuflicient soon as the pressure within the condenser drops to normal, the valves 9" and 10" close in responseto the operation of the thermo-.

static ,devicea The complete operation is as follows:

Assuming that the partsare in the position indicated in the drawing wherein the valve 8" is shown as open and the ejector 8 is operating to eject air from the condenser, the valve 8" is held open by the pin 23, by

reason -of its engagement with the valve lever 8*. If the quantity of air entering the condenser '1. during a given period of time, is greater than the ejector 8 is capable of extracting during the .same period and condensing all the steam supplied thereto, it will be apparent that the pressure within assuming that the condenser is. capable of the condenser 1 will increase proportionally v with the accumulation of air, which will in turn cause the temperature of the steam entering the condenser to increase correspond I ingly. This condition causes the thermostat tube 15' to. expand, thereby causing a movement of'the valve bar 21 to the right, so as to open the ejector valve 9", thus causing "the ejector .9 to assist the ejector '8. If the ejectors' Sand 9 are still incapable of .extracting all the air entering thecondenser the pressure will continue to rise in the condenser and the temperature of the incoming steam will rise correspondingly, occasioning further expansion of the thermostat tube 15, and thereby causing the valve bar 21 to moveto' the right unt l it opens the valve 10; controlling the delivery of motive fluid to the ejector 10.

, As the air content is reduced the pressure in the condenser 1 falls, resulting in a contraction of the thermostat tube 15, which. action draws the valve bar 21 to the left,

permitting the valves 10 and 9" to be closed successively in the order named. As will be apparent, the lengthof the bar 21 may be adjusted to meet the varying con.-

dlflOIlS encountered in the operation ofthe I condensate will cause both the tu device when operating .in summer or w1nter, or to suit the characteristics of the individual condenser. It will be apparent that normal variations in both the temperature of the incoming steam and the outgoing l5 and 16 to expand or contract corresponding amounts and will therefore not vary the operation of the ejectors.

Vhile I have described and illustrated but one embodiment of myinvention, it will be apparent to those skilled in the art that various changes, modifications, additions and omissions may be made in the apparatus described and illustrated without departing from the spirit or scope of the invention, as set forth by the appended claims.

VVhat'I claim is:

1. In combination with air extracting apparatus for extracting noncondensable fluid v frbm a condenser, a motive vfluid supply therefor, and controlling means for the motive fluid supply responsive to relative variations in temperature between the fluids entering the condenser and the condensate within the condenser.

2. In combination with a plurality of air extracting devices for extracting non-condensable fluid from a condenser, a motive fluid supply for said devices and controlling means for the-motive fluid supply respontween the fluid entering the condenser and sive to relative variations in temperature between the fluid entering the condenser and the, condensate formed therein.

3. In combination with a plurality of fluid operated air extracting devices for extract ing non-condensable fluids from a condenser, means for controlling the delivery of'mot-ive fluid to each device, and means responsive to relative variations in temperature bethe condensate leaving the condenser for successively actuating said first mentioned means.

4. Incombination with ejector apparatus for extracting non-condensable fluid from a condenser, a means responsive to relative variations in temperature of the fluid entering the condenser and the condensate therein.

therein, for increasing the motive fluid admission to the ejector apparatus as said difference in temperature increases.

5. In combination with ejector apparatus for extracting fluid from a condenser, a means responsive to relative variations in temperature of fluid entering the condenser and the condensate therein, for decreasing the motive fluid admission to the ejector apparatus as said difference in temperature decreases.

6. Condensing apparatus comprising in combination a condenser receiving steam to be condensed, fluid actuated means for ejecting non-condensable fluids from the condenser and thermostatic means for controlling the motive fluid admission to the ejecting means responsive to relative variations in diiference in temperature between the steam entering the condenser and the condensate withdrawn therefrom.

7. Condensing apparatus comprising in 8. Condensing apparatus comprising in combination a condenser receiving steam,

.means within the condenser for condensing the steam, fluid actuated means for ejecting the non-condensable fluids from thecond'enser, means for controlling the motive fluid admission to the ejecting means, and a pair of expansion ,members .adjustably connected tqthe controlling means and adapted to actuate the controlling means when their relative temperatures vary, and subject respectively to the temperature of the steam entering the condenser and the condensate 9. Condensing apparatus comprising" in combination a condenwr receiving steam, means within the condenser for condensing the steam, fluid actuated means for ejecting non-condensable fluids from thecondenser,

means for controlling the admission of motive fluid to the ejecting means, and a pair of hollow expansion members for operating the controlling means when their relative temperatures vary, one ofsaid members receiving steam from the condenser and being subject to the heat thereof and the other receiving condensate from the condenser and being subject to the heat thereof. j

10. Condensing apparatus comprising in combination "a condenser receiving steam,

means within the condenser for condensing the steam, fiuld actuated means for e ecting non-condensable fluids from the condenser,

- means for controlling the admission of motive fluid to the ejecting means, and a pair of hollow expansion members for operating the controlling means when their relative temperatures vary, through one of which steam from the condenser is circulated, and

through the other of which condensate from the condenser is circulated, and each being subject to the heat of the motive fluid supply including means responsive to variations in the temperature of the gaseous fluid entering the condenser.

12. In combination with a condenser, a

the fluid passing thereplurality of air ejecting devices for withdrawing non-condensable fluids from the condenser, and thermostatic means responsive to variations in the relative temperatures of the steam entering and the condensate withdrawn from the condenser for controlling the operation' of said devices.

13. In combination with a condenser, a plurality of air ejecting devices for withdrawing non-condensable fluids from the condenser, means for rendering one or more of said devices operative or inoperative, and means responsive to variations in the relative difference in the temperature of the steam entering and the condensate leaving the condenser for controlling the operation of said first mentioned means.

In testimony whereof, I have hereunto subscribed my name this 6th day of November,

RAYMOND N. EHR-HART.