US1797841A - Scoop-condenser apparatus - Google Patents

Description

z 1931- H. F. SCHMIDT 1,797,841

SCOOP CCNDENSER APPARATUS Filed May 31, 1928 VOLUME INVENTOR l-LEschmidl' Cl), V5. W

ATTORNEY WITNESS PatentedMah 24, 1931 mirnsnzr. somvrrnr, or LANSDOWNE, PENNSYLVANIA, AssIGivoRvro wnsrms sonsn ELECTRIC & MANUFA TURING-COMPANY, A'CVORPOBATION. or PENNSYLVANIA I scoor-colvnnivsna APPARATUS I Applieationfiled May 31,

Thisinvention relates to scoop condensers and it has for an object to improve the chiciency of condensers of this type.

In the operation or this class of equipment, it has been the practice to provide auX- iliary circulating pumps for accelerating the rate of flow of the circulating water when after the main engines are reversed and after the wash fromthe propellers becomes efiective' to oppose the circulation which might otherwisebeproduced by the forward motion of the ship. Also, after the vessel has lost its forward headway and is gaining headway astern, the back pressure created by the wash from thepropellers and the astern motion of the ship is, likewise, efliective, either in greatly reducing, or even in reversing the flow of circulating water.

conditions just described produce variations in-the dilferential pressure across the condenser." WVhile an attendant may ascertain from'the vacuum gauge that the circulation should be improved, hehasno means of'determining the direction in which the circulating water may be passed with the least resistance. Moreover, since, in. the reversal of a ship, thelossof vacuum and also'the accumulation of aniexcessive pressureflin the condensers. mayvtake' place almostinstantaneousr 'ly, the only course. of procedure, which has beenconsidered safe, is for anattendant in charge of the auxiliary pump to see that this pump is operatedlt'o capacity at the first indication of a falling, ofi ofthe va'cuum.

"Consequently, merely reversing the circu lating pump will not overcome these difficulties, since no means haveb'en provided for pump if it were designed to handle the full It will readily be seen, therefore,; that the 1928 Seria1No.2 81, 983. I g

ascertaining the, proper time to change the directlon of flow.

I Since the 'circ lating pump in the usual installations must befahle to discharge water against the bacl; pressure created" by the asterninotionof the shipand the wash'from thepropellers, an unduly large driving turbine; woulc he required for the, circulating amount offcirculating water 'required by the condensers,"However, the auxlllary circulat-. ingjpumps are generally made of very much reduced capacity and power, and in the case of destroyers and high speed naval vessels, 9

great care has'to be exercised in going astern atfullpower,inview of the relatively small 7 capacity and power of the auxiliary circulat ing pump, to avoid building up anexcessive' steam pressure in the condenser when the vessel is coming to restur d l ,Furthermore, in some cases, the aniountpf steam required for operatingzthe circulating pump becomes quite large; Intact, the quanltity of steam requiredfor this purpose may amount to as much, or more, than thatre: quired the main engines? It' 1nay thus occur, that, in suddenly changing from for ward to aster-n, the auxiliary circulating pump throttlevalve may be opened so quickly that the demand for steam by'the' circulating pump 'may cause a reduction in the boiler pressure sufficient to interfere with the maneuvering of the mainfengines. On t-he other hand, if; advantage is taken of the ahead motion of the ship, or of the astern motion and the ash of the propellers, a relatively small amount of poweriis suficient to handle tllGillll volume of'circulating water required;

: More particularly, therefore, an object of r my invention is to provide .for assisting the flow of circulating water, in ascoop conk denser,by means of fluidltranslating apparatus which is,prefe rably, reversible inure sponse to the attainment of predetermined difierential pressures, whereby the translating forces developed bythe translating apparatus may be combined, either with thetrans lating forces due to the ahead motion ofthe ship,or with those due to the astern motion and to the wash from the propellers, the par-. 100

ticular combination of forces depending, preferably, upon the attainmentof a pressure difi'erence which is suflicient to produce the required flow through the circulating system.

This and other objects is effected by my invention, as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which 'Fig. 1 is a diagrammatic view of apparatus'illustrative of principles of my invention, and v, r

Fig. 2 is a graph showing characteristics of a pump which may be used with apparatus of the type described. i

In accordance with a preferredform of my invention, the fluid translating'apparatus takes the form of a propeller pump, which is mounted in one of the scoops,and which is adapted to be operated by a reversible motor, such, for example, as a reversible turbine,

'or an induction motor. In this connection,

it is noted that my novel arrangement of condenser, scoop system and auxiliary circulat ing pump is disclosed and claimed in my copending application, Serial No. 515,759, filed February 14:, 1931, entitled Condenser circu- -latin'g system and assigned to the Westinghouse Electric and-.Manufacturing Company.

The direction of rotation of the motor is controlled, preferably, by a piston in a work- The pressure cifi'erence across a 'manner similar 'to the functioning. of a pilotvalve 1n a fluid pressure relay. Means are provided for restraining the movement. of'the piston, and-hence, the reversal of the motor, until the proper pressure difference prevails across the propeller of the pump.

Means are arso provided for preventing the reversal of the motor due to a pressure difference,'whichthough of theproper value,

might be due to clogging ofthecirculating system, instead one a reduction of speed, or to running'astern. Referring now to. the drawing for a better understanding of 'my invention, I show a ships hull 10, having a bottom 11, and a condenser 12 supported in any suitable ma-nner by the ships hull. The condenser is of the'scoop type and it has conduit, orscoop portions 13 and 14: arranged at the forward and astern ends, respectively, the conduit portion 13.terminating at its forward end in projecting lip or scoop construction 15' of any suitabledesigm In order that the objection of loss of power and consequent possible serious reduction of boiler pressure, .due to the necessity heretofore, .of overcoming the velocity head of coolingwater when running asterinmay .be'overcome, .I provide areversible propeller 17in the forward conduit 13, the reversible propeller being, carried by a shaft 18, whose outerend is connected to a suitablemotor, at

passages 22 20. In the form shown, the motor at 20, takes the form of a reversible steam turbine, al-

though any reversible motor may be used for operated to supply steam through either'the passage 22 or the passage 23 so that the turbine may be operated either in one direction or the other, I show pressure responsive means for controlling such valves, this pressure responsive means preferably taking the form ofapparatus which is responsive to a predetermined differential pressure in either direction across the propeller 17. To this end, I

peller 17, the other ends of these conduits being connected to the cylinder 29 adjacent to the endslof the latter, the clyinder 29 contaming a piston 30'connected' to a rod 31, which cooperates with a lever 32 for actuating the valves 24 and 25 in order that steam may be supplied alternatively through the and 23 to secure operation 01 the turoiue in either direction.

' In order that the lever 32 may be moved sufficiently in either direction to fully close one valve and open the other, as well as to impose sufficient resistance on the piston rod 31 so that the latter will not be moved until a predetermined differential pressure isat tained across the propeller 17, I provide a spring toggle mechanism, 33, which, not only serves to afford this resistance, but also secures a positive snap-overactionin either direction in orderto fully close one valve and to fully open the other. Due to the resistance of the spring toggle mechanism, it is assured that minor fluctuations in differential pressure across the propeller, such as may occur .When a ship is being maneuvered for docking,' shall not result in reversalof the tur hine. F or example, the spring toggle-mechanism may be so designed that a speed of 10 any reason, the valves would come into opershow conduits 27 and 28 opening into the conduit 13 at opposite sides of the proration and reverse the direction :of, rotation and flow through thecondenser.

The building up of pressureoin eXcess of thenecessa-ry 10. feet would be caused, either lay-reversal of, direction-of the ship, or' by the clogging ofthe condenser tubes with sea weed, or other foreign matter. 4

:It is further obvious, that should seaweed, fish, rubbisl1 ,':.or other debris be caught on the tube sheets, the reversal of flow will wash such obstructionsoverboard and automatically keepthe condenser clean. v

Asshown on the drawing, the vessel, is proceeding-forward, or to the right, the scoop 13 beingthe vforward scoop. -Under these conditions the'velocity of flow through the conduit or scoop portion 13 is relatively high and the pressure difference between the front and rear sides of thepropeller is relatively small. The piston 30 is at the leftendof its stroke in flthe cylinder 29, and although the pressure inthe. passage-'28 under these conditions is greater than that in the passage 27, the difference of pressure across the propeller issolsmall asto be inefiectivefagainst the: toggle mechanisnnand as long as these conditions prevail the toggle mechanism will holdthe piston 3Q in this position.

In thegraph shownin Fig. 2, the pressure volume characteristic and the efficiency curves for a propeller type pump are shown. vAt the pointtl-on the pressure volume. curve the pump is; operatingatits maximum efficiency.

This is, preferably, the point atirwhiclrthe pump is operating as shown in'the drawings for normal forward speeds oft'he'vesseL Since the ordinates of the pressure-volume curve are the PIQSSLIIQ-dlffGTGDCBS across the propeller, it will be'clear that as the quan-e tity or volume, of water delivered decreases, the pressure difference will increase. Hence, as the forward speed ofthe vessel is reduced, the forward scoop '13 becomesle'ss effective and "supplies a smaller quantity of water and the burden on the pump increases. It will be clear therefore, that at some pointon the pressure volume curve, such as at the point 42, :the pressure difference acrossthe ropeller will be great enough to overcome theresistance iofi'ered by the toggle mechanism and to move the piston 30-to the right and thus, to-reverselthe pump.

It will also be obvious that the reversal "of the pump is effected, .when changing from astern to aheadoperatiomin the same manner as that just described, such reversal result-V ing in the various parts returning to the positions in which they areshown on the drawing. i I

"It will be understood, of"course,'that at high speeds, very little worlrneed be done by. the-pump and in fact at such speeds the'scoo-p effect may be so great that the flow of water will actual'ly'runthe'pump yas a water turbine. Under these co'nditions,= the} press i sure difference across then-propeller would be svery smalland the toggle mechanism would hold the piston 30. in'the proper position. A i a 'In changing from ahead to astern operation, a vessel may have considerable forward headway even after themain engines have beenreversed and after the wash from the propellers has become effective to oppose the, "flow of circulating water through the astern scoop .and through the condenser tubes. Hence, itis desirable that the flow through the condenser tubes be reversed before the vessel has completely lost its forward-headway, as otherwisethe circulating pump would have to oppose the pressure head due to th wash from the propellers.

" It will be apparent that the apparatus thus far described is capableofattaining these astern.

"With the apparatus thus far described, there is a possibility of the circulating system becoming so clogged with dbris,and the like, and thus offering s'uflicientresistance to the flow ofthe circulating water to produce the pressure difference required to reverse the pump while the vessel isproceed ing forward under considerable headway.

Should this occur, the pump would be operat- 7 ing against the velocity head due to the forward motionof'the ship. j

' In order to prevent an occurrenceof this kind, I connect the piston rod 31 to the piston 23% in-theworking cylinder 36, The'actuating medium is introduced and discharged 7 from the cylinder36 by m'eans of the Pitot tubes 37 and 38, which extend through-the hull 1'1, tothe ports of the cylinder,the tube 37 being pointed forward, while'thetube 38 is pointed During'forward motion of the ship,

the velocity head of the waterwill be avail able through the tube 37to move the piston 34jto the left and to'hold it-there until the speed is considerably reduced; Should the vesselbe proceeding astern, the velocity head duetothe wash fromthe propellers and to the 'astern motion-will act through the tube 38 to move thep'i'ston to the right and to holdit in this position."

I It'will be apparent, therefore, that a pressure difference due to the accumulation of debris in thecirculating system, cannot effect 'areversal' of the pump in suchja way as'to cause'it to oppose the pressure head due to any appreeiable'speed of the'ship; Moreover, should a pressure difference, due

tofclogging or the like, occur at a low speed i where thevel y head" s f lit le. effect i he cylinder 36,- thereversal of the pump scoop type wherein the objection of the .cir-

culating pump opposing thevelocity head of coolingwater when runnmg astern is avoided, advantage being taken of the propulsion speed in either direction to secure passage of coollng water through the condenser in either direction, depending upon pressures prevailing at the scoops. Another advantage of the present construction .is that the condenser system may be readily evacuated of seaweed,

the condenser will be capable of producing the required vacuum under all conditions of operation.

In addition to producing the required vac uum under the various conditions of service, my apparatus is arranged to operate with minimum consumption'of power.. As previously pointed out, neither the direction of motion of a vessel, nor the point at which that direction isreversed, may be taken as an indication of the condition of flow in the circulating system of a scoop condenser. For these reasons, it has been the practice to pro vide auxiliary circulating pumps of very large capacity so that water may be forced through the tubes in the same direction whether proceeding ahead or astern, the reason for this practice being that regardless of which way the water is forced through the tubes, there is a pointat which the pump must be capable of opposing the velocity head.

due to 'the motion ofthe vessel, since the apparatus of the prior art is not adapted to 1 function in response to variations, or changes in the actual conditions of flow. Since my pumping apparatus is arranged to operate in phase with any appreciable changein head, itwill be clear that I may use a much smaller pump than has heretofore been considered adequate, and consequently, I may thereby effect a saving in power consumption as well as in the first costof equipment. Furthermore, it will be obvious that my pumping apparatus may be operated continuously, oronly at reduced speeds and when running astern.

lVhile I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes .and modifications,

without departing. from the spirit thereof,

tions shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

lVhat I claim is 1. The combination with a condenser of the marine type having conduit port-ions communicating with the ends thereof, a propeller arranged in one of the conduit portions, a reversible motor for driving the propeller, and means depending upon the difierential pressure across the propeller for controlling the direction of rotation of the motor.

:2. The combination with a marine condenser of the scoop type having conduit portions communicating with the ends thereof, a propellerarranged in one conduit portion, a reversible motor for driving. the propeller, conduits communicating with the conduit containing the propeller at each side of the latter, a pressure responsive device connected to said conduits, controlling means for the reversible motor, and means for actuating the controlling means from said pressure responsive device.

3. The combination with a marine condenser having cooling water conduit portions communica-ting with the ends thereof, a propeller arranged in one cooling water conduit portion, a reversible motor for driving the propeller, passageways communicating with the cooling water conduit portion containing the propeller at each side of the latter, a cylinder communicating with said passageways, a piston in the cylinder, and controlling mechanism for the motor operatively connected to said piston. r

4. The combination with a marine condenser of the scoop type having cooling water conduit portions communicating with the endsthereof, of'a propeller'arranged in one conduit portion, a reversible motor for driving the propeller, controlling'means for the motor, and means responsive to a predetermined differential pressure in either direc tion across the propeller for rendering efiective the controlling means. i

5. The combination with a marine condenser and scoop means for circulating coolingwatertherethrough, of auxiliary pumping means for circulating cooling water through the condenser, means for reversing the directionof flow of the water clrculated by said auxiliary pump ng means, and means responsive to a characteristic of the water of circulation for controlling the direction of flow of the waterscirculated by said auxiliary pumping means.

6. The combination with a marine condenser and scoop meansfor circulating cooling water therethrough, of auxiliary pumping means for circulating cooling water through the condenser, means for reversing the direction offlow of the water circulated by said auxiliary pumping means, means responsive to a characteristic of the water of circulationfor reversing the direction of flow of the water circulated by said auxiliary pumping means, and means for restraining the reversingmeans, whereby frequent reversals due to slight changes 1n the characteristic of the water of circulation are avoided.

7 The combination with a marinecondenser and scoop means for circulating cooling Water 'therethrough, of an auxiliary pump for circulating cooling water through the condenser, said auxiliary pump being redriving the propeller, and means responsive to a pressure characteristic of the water of circulation for controlling the direction of rotation of the motor.

In testimony whereof, I have hereunto subscribed my name this 29th day of May, 1928.

HENRY F SCHMIDT. V f

versible so as to effect :a direction of flow I through the condenser in either an ahead or an astern d1rection,'and means responsive to a characteristic of the water of circulation for controlling the pumping direction of the for circulating cooling water through the condenser, said auxiliary pump being reversjss ible so as to effect a direction of flow through the condenser in either an ahead or an astern direction, means'responsive to a characteristic of the water of circulation for controlling the pumping direction of the auxiliary pump, and means for restraining the reversing movements of the auxiliary pump, whereby frequent reversals due to slight changes in the characteristic of the water of circulation are avoided.

9. The combination with a marine condenser, of a reversible pump for circulating cooling Water therethrough in either an ahead or an astern direction, and means responsive to a characteristic of the water of circulation for controlling the pumping direction of said pump.

10. The combination with a marine condenser, of a reversible pump for circulating" cooling water therethrough in either an ahead pump, and means for restraining the reversing movements of the pump, whereby frequent reversals due to slight changes in the r characteristic of the water of circulation are avoided.

11. The combination with a condenser "of the marine type having conduit portions communicating therewith for supplying cooling water thereto, of a propeller arranged in one of the conduit portions for effecting a circulation of cooling water through the, condenser, a reversible 7 motor for driving the propeller, and means responsive to a characteristic of the water of circulation for controlling the direction of rotation of the motor. r

12. The combination with a condenser of I the marine type having conduit portions communicating therewith for supplying cooling water thereto, of a propeller arranged-in one of the conduit portions, areversible motor for

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