US1980784A - Elastic fluid generator - Google Patents

Description

Nov. 13, 1934. B. P. couLsoN JR v 1,980,784

ELASTIC FLUID GENERATOR Filed Oct. 1, 1932 2 Sheets-Sheet 2 Invenoom Bevis P Goulson Jn,

necessarily limited thereto.

Patented Nov. 13, 1934 ELASTIC FLUID GENERATOR Bevis P. Coulson, Jn, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application October 1, 1932, Serial No. 635,770

18 Claims.

The present invention relates to elastic fluid generators such as are used. for heating and evaporating mercury and like fluids to be used in mercury vapor turbines, although it is not A mercury vapor generator has to meet certain requirements which are not apparent in steam generators. This is due primarily to certain properties of mercury and the high cost of this liquid.

One object of the present invention is to provide an improved elastic fluid generator, particularly adapted for the generation of mercury vapor in which the necessary amount of mercury liquid is considerably minimized in comparison with r the amount of mercury which heretofore has been necessary in generators of this kind.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the acc0mpanying drawings which form part of my specification. l i

In the drawings, Fig. 1 is a perspective View of a mercury vapor generator, partly broken away, embodying my invention; Fig. 2 is a front view of a part of the generator; Fig. 3 shows a side view, partly in cross section, of a part of Fig. 1; and Fig. 4 is a diagrammatic illustration of a power plant including an elastic fluid generator embodying my invention. Like reference characters denote like parts. The direction of flow of fluid through the different parts is indicated by arrows. 2

Referring to the drawings, the elastic fluid generator which has been shown in the present instance as a mercury vapor generator comprises a plurality of drums for containing mercury liquid 11 to be evaporated. The liquid space in each of the drums is partly filled with cores or blocks 12 which serve to displace a portion'of the liquid in the liquid space in order to-minimize the necessary amount of liquid for'operating the generator. The drums are provided with liquid heating and evaporating tubes 13 such as for instance are shown and more fully described in the copending application of Emmet and Coulson, Serial No. 306,486, filed September 17, 1928. Each drum 10 has a vapor conduit 14 connected toa header, termed vapor header 15 (Fig. 2) for supplying vapor from the drums to aconsumer.

In order to distribute the liquid equally among the drums I connect the latter with each other by means of pipes, termed liquid equalizingpipes. In the drawings, I have shown liquid equalizing pipes 16 connecting the front heads 17-of adjacent drums with each other. The rear heads of the drums are connected in similar manner by liquid equalizing pipes 18 as shown in Fig. 3; According to my invention, the liquid equalizing pipes have at least a section located above the cold liquid level in the drums, and in the present instance are connected to the drums at points above the cold liquid level and below the hot liquid level. More specifically I prefer an arrangement in which the lower edge ofthe pipes is above the cold liquid level andthe upper edge of the pipes above the hot liquid level. With such an arrangement the equalizing piping does not contain any liquid during cold condition of the generator. During operation, that is, during heating, the mercury expands about 10% of its volume with respect to the usual temperature and pressure conditions in present day mercury vapor plants. This expansion and also the expellingof mercury from certain portions of the tubes causes a rise of the liquid level to a point above the lower edges of the equalizing pipes. In order to ensure that no'mercury is contained in the equalizing pipes during cold condition and to cause an easy flow of mercury from these pipes into the drums, the pipes are slightly inclined by an angle X (Fig. 3) downwardly towards the drums. The liquid equalizing pipes 16 provided at the front of the drums are connected to conduits 19 for supplying liquid to the drums. Each of the conduits 19 has a bent portion 20 filled with mercury to define a liquid pool. With this arrangement liquid flowlug-through the pipe or conduit 19 does not drop on a portion of the wall of the conduit which would cause wear of the conduit but actually falls into the mercury pool in the conduit portion 20. Another important function of this pool will be described later.

Besides the drums, the elastic fluid generator comprises a plurality of heating units which may 5 be termed liquid preheating and evaporating units 21." In the present instance I have shown one heating unit for each drum arranged so that two heating units are'located between two consecutive drums. The units serve for heating and evaporating liquid. The heated liquid is supplied to the drums whereas the vapor is supplied to a consumer. Each unit 21 has a primary part 22 and a secondary part 23. The primary parts each have a lower header 24 and an upper header 25 with a plurality of tubes 26 therebetween. In similar manner the secondary parts comprise alower header 2'7, an upper header 28 and a plurality of tubes 29 connecting the headers. The rear ends of the upper headers and 28 of said parts are connected by conduits 30. The primary parts are shorter than the secondary parts and are located adjacent the upper portion of the secondary parts, preferably so that the upper headers 25 and 28 are at the same level. The front ends of the lower headers 24 are connected by pipes 31 which in turn are connected through a conduit 32 to a liquid supply header 33. During operation, liquid mercury is supplied from the liquid header 33 through the conduits 32, 31 into the lower headers of the primary parts. During heating, therliquid flows from the lower headers 24 upward through the tubes 26 into the upperheaders 25 and from the rear end thereof through the conduits into the secondary parts. The heating of the liquid continues in the secondary parts and a. part of the liquid is evaporated therein. Whereas an upward flow of the liquid takes place in the primary parts without circulation of the liquid within these parts, I provide a design for the secondary parts which causes the liquid to circulate therein. To this end I have shown the secondary parts as including large tubes 34 and small tubes 35 which are provided so that a plurality of small tubes is arranged between two large tubes. The liquid flows downwardly through the large or down-tubes which cause comparatively less heating of the liquid and upwardly through the small or up-tubes. The circulation of a fluid particle through a down-tube, a'portion of the lower header, an up-tube and back to the upper header takes place several times until the parsecondary part.

ticle reaches a succeeding down-tube where the sameheating process is repeated. Thus a particle entering the secondary part of the heating unit circulates and recirculates a great many times through the different portions of the secw units, the vapor beingsupplied through conduits 37 to a consumer, and the liquid being supplied to the drums through conduits 38 forming in substance extensions of theconduits 19. The conduits 37 of adjacent units are connected through a single conduit 39 to the vapor conduit 15. The device 36 comprises an outer cylinder 40 having a bottom 41 communicating with a down-pipe and a top portion 42 located somewhat above the upper header '28 and connected to the conduit 3'7. Concentrically arranged within the outer cylinder 40 is an inner cylinder 43 having a small orifice 44 provided in the bottom thereof and a lower portion connected to the conduit 38. The upper end of theinner cylinder'has a V notch 45 providednear the level of the upper header 28.

During cold condition the liquid level in the sec-, ondary unit is determined by the level of the connection between the inner cylinder with the pipe 38. During operation, the secondary unit is filled with liquid having a level near the upper edge of the'V notch as indicated by a line aa in Fig. 3. As soon as the generator is shut down apart of the liquid contained in the secondary parts of the units escapes through the orifices 44 of the inner cylinders and the conduits 38, 19, and 16 into the drums. This is another important feature of my invention as it permits a further saving of a considerable amount of mercury or like liquid.

An important function'of the device 36 is that it permits a rise of the liquid level in the secondary unit during operation of the generator. During starting, the mercury contained in both the primary and secondary parts of the units expands. The expanding liquid together with the liquid supplied to the primary part causes the level in the secondary unit to rise until it reaches the V notch of the device 36. The orifice 44 in the inner cylinder is small so that during this time only little liquid escapes through the inner cylinder and the conduit 38 into the drum. The liquid thus gradually fills the space between the outer cylinder 40 and the inner cylinder 43. In a preferred embodiment I make the orifice 44 in the bottom of the inner cylinder of a size which permits the escape of all the mercury above the no-load liquid level in the secondary part of loads below one-eighth of the normal load. In this case, the upper part of the secondary unit is being filled only at loads above one-eighth of the normal load. As soon as the liquid level rises above the lower edge of the V notch, a part of the liquid flows into the interior of the cylinder 43 and through the pipe 38 to the drum.

From another viewpoint, the conduit 38, to gether with the inner cylinder 43, represent means for conducting liquid from the heating unit or units to the drum or drums. This means includes a portion having a small orifice at an intermediate point of one of the vertical tubes of the unit and another portion communicating with the upper header of the secondary part. It will be readily understood that'with an intermediate point, I mean a point located at a level intermediate the lower and upper header of the secondaryv unit.

In order to save some of the liquid contained in the. primary parts or heaters I connect the upper headers 25 of said heaters through a small pipe 49 with an intermediate point of a downtube 34 ofthe secondary parts. With the arrangementof the pipes 49 the upper headers of the primary parts are emptied when the generator is shut down, the liquidflowing through the secondary parts into the drums.

In the case of a mercury vapor plant (Fig. 4) the vapor line, 15 conducts mercury vapor to a turbine 46 to which is connected a condenser 47 for receiving exhaust from the turbine and sup plying the condensate through the liquid header 33 to the heating unit or units. The liquid header 33,-as shown in Figs. 1 and 4, is provided at a level above the drums and the heating units, so that no mercury is contained in the header While the unit is cold which means another saving of the mercury necessary for operating the plant.

From a consideration of Fig. 4, another important function of the liquid pool defined by the bent portion 20 of pipe 19 becomes apparent. Thence it will be seen that during cold condition, the conduit 19 between the drum and the heating unit communicates with the spaces above the liquid spaces in both the drum and the heating unit (see also Fig. 3). Without the pool in the portion 20 of theconduit 19, vapor could escape from the drum during the starting operation through the conduit 19, the inner cylinder 43 of the device 36, and through conduit 37 into the vapor line 15 (Fig. 3). The flow of vapor from the drum into the heating'unit would obstruct the flow of liquid in the opposite direction. This is effectively prevented by the pool in the portion 20,0f the 'conduit 19 which in this respect represents a vapor sealing means between-the drum and the heater.

As described above, liquid is supplied to the heating units through the conduits 32 which in turn receive the liquid from the liquid header 33. In order to ensure an equal supply of liquid for the diiferent drums during the starting operation, that is, to prevent the units near the condenser from receiving more liquid than those away from the condenser, I connect the conduits 32 by means of pipes 48 (Fig. 2). In case one of the units, for instance, the one shown on the righthand side of Fig. 1, receives more liquid through the conduit 32 than the unit shown on the lefthand side, a part of the liquid supplied from the conduit 33 will flow through the pipe 48 into the left-hand unit. The pipes 48 accordingly repre sent means for equalizing the supply of liquid to the heating units during the starting operation. The equalizing function of the pipes 48' ceases or becomes negligible as soon as a sufiicient amount of liquid flows from the condenser through the liquid header 33.

Summarizing the important features and the operation of my improved elastic fluid generator: During cold condition of the generator no liquid is contained in the equalizing piping between '1 the drums, the upper headers of the primary parts, the upper headers and an upper portion of the tubes of the secondary parts, and the liquid supply header. During operation, the expansion of the liquid and the expelling of liquid from certain parts of heating tubes 13 causes a rise of the liquid level in the drums above the lower edge of their connections with the equalizing pipes; the expansion of the liquid in the heating units and the supply of liquid thereto causes the liquid level in the secondary parts to rise until the units become substantially filled with liquid. The vapor generated in the drums and the units is supplied through the conduits l4 and 37, 39 respectively, into the vapor header 15, whence it is conducted into a consumer such as the turbine 46. The condenser 47 connected to the turbine supplies the condensate through the liquid supply header 33 to the heating units 21 which are connected by equalizing pipes 48. The liquid evaporated in the units is conducted to the vapor line 15 and the remaining liquid is supplied to the drums. With respect to the liquid supplied to the drums, the heating units represent means for preheating condensate and supplying it to the drums. The conduit 19 between the heating units and the drums has a bent portion filled with liquid which liquid defines a pool for preventing wear of the piping owing to the mercury fiow through these conduits; furthermore this pool defines a vapor seal between the spaces above the liquid levels in the drums and the units during starting condition. A rough calculation shows that with my improved elastic fluid generating arrangement, a saving of 15,000 to 20.0% lbs. of mercury can be made in a 20,000 kw. mercury vapor-steam power plant.

Having described the method of operation of my invention, together'with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that: the invention may be carried out by other means.

What I claim as new and desire to securehy Letters Patent of the United States, is:

1. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealed in the system and stands at a predetermined level when cold, a plurality of drums for containing mercury liquid to be evaporated, and aliquid equalizing pipe between two drums having its ends connected to said drums at points abovefthe cold liquid level. and below the hot liquid level.

2. In a mercuryvapor generator, a plurality of drums for containing mercury liquid to be evaporated, and equalizing pipes between adjacent drums for securing an equal distribution of liq uid among the drums, said pipes being inclined downwardly towards the drums and having their ends connected to the drums at points above the cold liquid level and below the hot liquid level whereby the pipes are empty during cold condition ofthe liquid.

3. In a mercury vapor generator of the type in which a fixed quantity of 'fiuid is sealed in the system and stands at a predetermined level when cold, a plurality of drums for containing mercury liquid, liquid equalizing pipes between the drums, a header connected to each of, the drums for supplying liquid thereto, the drums being filled with mercury liquid having during cold use condition a level which is below the equalizing,

units including means for separating liquid from vapor and supplying the liquid to the drums, and means for receiving Vapor from the drums and the units.

5. In a mercury vapor generator of .the type in which a fixed quantity of fluid is sealed in the system and stands at a predetermined level when cold, a drum for containing liquid tobe evaporated. and a liquid heating unit having a lower header and an upper header with a plurality .of substantially vertically arranged tubes therebetween, an intermediate portion of' said tubes located above the liquid level in the drum being connected with the drum to conduct liquid to the drum and to fix the cold liquid level in the heating unit, the upper header being located above'the liquid level in the drum. q

6. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealed in the system and stands at a predetermined level when cold, a drum for containing liquid to be evapa orated, a vapor conduit for the drum, a heating unit having a portion located above the liquid level of the drum and comprising a lower header,

an upper header and a plurality of substantially vertical'tubes between the headers, and a liquid vapor separating device connected to the upper header and the lower header, an intermedirib ate portion of said device located above the liquid level in the drum being connected to the drum above the cold liquid level therein for conducting liquid from the heating unit to the drum and for fixing the cold liquid level in the heating unit.

'7. In amercury vapor generator of the type in which a'fixed quantity of fluid is sealed'in the system and stands at a predetermined level when cold, a drum for containing liquid to be evaporated, a vapor conduit for the drum, a heating unit having a portion located above the liquid level of the drum and comprising a lower header, an upper header and a plurality of vertical tubes between the headers, and a liquid vapor separating device connected between the upper header and the lower header, said device including a conduit having-one end connected to the drum at a point above the cold liquid level and below the hot liquid level in the drum and another end connected to a portion of the device located above the cold liquid level of the drum for fixing the cold liquid level in the unit and permitting the hot liquid level in the unit to rise to a point near the upper header during operation.

8. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealed in the system and stands at a predetermined level when cold, a drum forcontaining liquid to be evaporated, a vapor conduit for the drum, a heating unit having a lower header, an upper header and a plurality of tubes between the headers, and a liquid vapor separating device connected between the upper header and the lower header, said device including a conduit having one end connected to the drum at a point above the cold liquid level and below the hot liquid level in the drum and another end connected to the device at a point above the cold liquid level in the device, a portion of the conduit defining a pool for containing liquid to prevent vapor'from passing from the drum into the heater.

9. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealedin the system and stands at a predetermined level when cold, a drum for containing liquid to be evaporated, a consumer connected to the drum for receiving vapor from the drum, a condenser connected to the consumer, a heating unit connected to the consumer and the condenser for sup- 3 plying vapor to the consumer and receiving condensate from the condenser, a conduit for conducting liquid from the heating unit to the drum, said conduit being connected above the cold liquid levels of the drum and the heating unit, and

; a pool in the conduit for defining a vapor seal between said drum and heating unit.

10. In a mercuryvapor generator of the type in which a fixed quantity of fluid is sealed in the system and stands at a predetermined level when cold, a drum and a heating unit for containing liquid to be evaporated, a vapor conduit connected to the drum and theunit, a liquid supply conduit connected to the heating unit, and a conduit for conducting liquid from the heating unit to the drum, said conduit having its ends connected to the spaces above the cold liquid levels and below the hot liquid levels in the drum and the unit, and having a portion containing a liquid pool for defining a vapor seal between the drum and the unit.

11. In a mercury vapor generator, a drum, a heating unit comprising a primary and a. secondary part, each part having a lower and an upper header with a plurality of tubes therebetween, a liquid supply header connected to the "lower header of the primary part, a conduit between the upper headers of the parts, another conduit for conducting vapor from the header of the secondary part, and conduit means for conducting liquid from an intermediate portion of one tube of the secondary part to the drum,

said intermediate portion being located above the liquid level in the drum, said conduit means fixing the cold liquid level in the secondary part of the unit and providing during starting for such a low rate of flow of liquid from the unit to the drum that the liquid level will rise in the secondary part during starting to a point near the upper header 'of the secondary part.

12. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealed in the system and stands at a predetermined level when cold, a drum, a heating unit comprising a primary and a secondary part, each part having a lower and an upper header with a plurality of tubes therebetween, a liquid supply header connected to the lower header of the primary part, a conduit between the upper headers, another conduit for conducting vapor from the header of the secondary part, and conduit means for conducting liquid from an intermediate portion of one tube of the secondary part to the drum, said intermediate portion being located above the liquid level-in the drum, said conduit means fixing the cold liquid level in the secondary part i of the unit and providing during starting for such a' low rate of flow of liquid from the unit to the drum that the liquid level will rise in the secondary part during starting to a point near the upper header of the secondary part, and a conduit between the upper header of the primary part and an intermediate point of a tube of the secondary part.

13. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealed in the system and stands at a predetermined level when cold, a drum for containing liquid to be evaporated, a heating unit having upper and lower headers with a plurality of tubes therebetween, means for conducting liquid to the unit, and conduit means for fixing the cold liquid level in the unit and conducting liquid from the unit to the drum, said means including a portion having an orifice communicating with an intermedipipes for containing liquid connecting the portions of said conduits for equalizing the liquid supply to the units during starting condition.

15. In an elastic fluid generator, a drum for containing liquid to be evaporated, a heating unit comprising an upper header, a lower header with a plurality of upand down-tubes therebea tween, a device having an outer cylinder connected between an intermediate portion of a down-tube and the upper header, said device including an inner cylinder having a bottom portion with an orifice and an open upper portion 1 with a V notch near the lever of the upper header, and a conduit for connecting a lower portion of the inner cyyinder to the drum. 7

16. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealed inthe system and stands at a predetermined level when cold, a plurality of drums and heating units for containing liquid to be evaporated, a consumer and a condenser connected in seriesto the drum and units, a liquid supply conduit between the condenser and the units located above the units, and a conduit for connecting each of the drums to one of the units, each of said conduits having a portion defining a vapor'seal between the drum and the unit.

17. In a mercury vapor generator of the type in which a fixed quantity of fluid is sealed in the cold, a plurality of drums, mercury liquid contained in the drums and a liquid equalizing pipe communicating with two drums and having at least a section located above the cold and below the hot liquid level in said drums whereby no liquid is contained in the section during cold condition of the mercury.

BEVIS P. COULSON, JR.

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