US 3578004 A
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United States Patent Inventors Le Roy A. Bromley Moraga;
Stanley M. Read, Occidental, Calif.
June 12, 1969 May 11, 1971 The Regents oi the University of California Continuation-impart 01 application Ser. No. 534,012, Mar. 14, 1966, now abandoned.
Appl. No. Filed Patented Assignee References Cited UNITED STATES PATENTS 1/1925 Hiller 2,519,618 8/1950 Wilson et a1. 159/14 2,545,028 3/1951 Haldeman 159/ 1 3A FOREIGN PATENTS 904,812 1 1/1945 France l59/13A 11,352 6/1890 Great Britain l59/13A Primary ExaminerWilliam R. Cline Attorney-Warren H. F. Schmieding ABSTRACT: A method of controlling the flow of volatile liquor from a container in a manner to l) maximize the ratio of liquor flow relative to vapor flow, (2) distribute the flow of liquor evenly to a series of parallelly disposed tubes although the inlets thereto are not in the same horizontal plane, (3) distribute the flow evenly against the interior walls of the tubes, and (4) accelerate the flow along the interior walls of the tubes to increase heat exchange with the environment about the tubes. The controller for canying out the method includes a tubular element having (I) a portion provided with an inlet in the upper part thereof for the flow of fluid thereto from the container, (2) a portion having a passage leading from the container downstream of the inlet and disposed for causing vortical movement to be imparted to the liquor entering the second mentioned portion through the passage, and (3) a throat downstream of the second mentioned portion.
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sum 2 0F 2 .L INVENTORS STANLEY M. READ LEROY A. BROMLEY r////// //A Z i' A T TORNE Y METHOD AND DEVICE FOR FLOW CONTROL OF LIQUOR BY VORTEX MOVEMENT OF THE LIQUOR CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of the copending application Ser. No. 534,0l2, filed Mar. 14. 1966, now abandoned, and one application of the disclosure is to control the flow of liquor from one container to another, such as the containers disclosed in the now abandoned application of Bromley. et al. Ser. No. 348,550, filed Mar. 2, I964. and the oontinuation-in-part thereof, Ser. No. 629,843, filed Feb. 15, I967, now Pat. No. 3,487,873.
BACKGROUND OF THE INVENTION l Field of the Invention Broadly, the invention is directed to the control of the flow of liquor from a container.
2. Description of the Prior Art The most pertinent art known to the applicants is the disclosure in the aforementioned application Ser. No. 629,843.
SUMMARY OF THE INVENTION The present invention is directed to a method employing a controller having characteristics of a steam trap which provides for the flow of liquor and minimizes, or if desirable, prevents the passage of vapor from one container to another. In carrying out the method, the liquor flowing from the one container to the other passes through a portion of the con troller in which vortical movement is imparted to the liquor and this liquor, while in a vortex, flows to a throat before entering the downstream container.
The method and the controller is useful particularly in multiple eflect flash evaporators such as that disclosed in the aforementioned application, Ser. No. 348,550, and the continuation-in-part thereof, Ser. No. 629,843, which latter matured into US. Letters Pat. No. 3,487,873 on Jan. 6, I970. The Letters Patent is hereby incorporated by reference into this present disclosure. In those applications, the floors such as the floors for pans or receivers such as receiver 128, have tubes depending therefrom, such as tubes 132 which depend from the floor of receiver I28. The inlet to those tubes are restricted as by orifices 126 which are more clearly shown in FIG. 3 of those applications. Should, for example, the floor of receiver I28 slant somewhat from horizontal, relatively less liquor and in some cases only vapor would pass through the tube having the higher inlet thereto resulting in an uneven flow of liquor through the tubes. Unle$ the floor is substantially level, uneven flow takes place resulting in uneven flow around the inside circumference of the tube. Such uneven flow could lead to drying in areas and scale formations.
The method and the controller of the present invention assures a constant flow of liquor through all of a multiplicity of parallel depending tubes, the flow being such that no drying takes place within any of the tubes although the inlets thereto are not in the same horizontal plane.
BRIEF DESCRIPTION OF THE DRAWING FIG. I is a cross-sectional view of the upper part of a multiple effect flash evaporator similar to that shown in the aforementioned Letters Patent, but showing a series of controllers of the present invention;
FIG. 2 is a longitudinal sectional view of one of the controls shown in FIG. I, but on a larger scale;
FIGS. 3 and 4 are cross-sectional views taken along lines 3-3 and 4-4, respectively of FIG. 2;
FIG. 5 is a graphical illustration of the flow characteristics, with varying head, in the controller;
FIG. 6 is a longitudinal sectional view showing the controller employed for conveying liquid from a lower container to an upper container; and
FIG. 7 is a sectional view taken along line 7-7 of FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The upper part of a multiple effect flash evaporator 20 includes a tank 22, having an upper container 24 which is formed by the upper part of the tank and a floor 26. This compartment receives liquor, for example sea water, through a pipe 28. A lower container 30 is formed by the sidewalls of the tank, the floor 26 of container 24 and a floor 32. It receives steam through a pipe 34 and the condensate is drained through a pipe 36. A series of tubes 37 have their upper ends hennetically joined with the floor 26 and extend through container 30 and through the floor 32 of the latter container. Each of these tubes 37 is provided with a restrictor as shown in FIG. 3 of the aforementioned Patent. The liquor is heated in the tubes and the pressure is consequently increased by the steam within container 30. The liquor falls into a third container in the form of a pan 38 having floor 39, which container is disposed below container 30 and in a compartment 40 which is formed by the sidewalls of the tank and a floor 42.
A series of the improved controllers 44 extend through the floor 39 of container 38 and each extends into a separate tube 46. The upper ends of tubes 46 are hermetically joined with floor 39.
Referring now to FIGS. 2, 3 and 4, the controller 44 is in the form of an elongated tubular element which is circular in cross section. The upper portions 50 of a series of these controllers extend through the floor 39 of the pan 38. The lower portions 52 extend into tubes 46 in compartment 40. The upper por tion of each controller forms an elongated passage 54. The lower part of passage 54 of portion 50 reduces regularly and progressively longitudinally in circular cross section downstream as shown at 56 and merges into a throat 58 below floor 39. A longitudinal passage 60 increases regularly and progressively in circular cross section downstream from the throat. The tube 46 extends downstream, i.e. below the outlet end of the controller and when used in a multiple effect flash evaporator as disclosed in the aforesaid patent, the area below the throat forms an expansion chamber. Passages 54 and 56, throat $8, passage 60 and tube 46 are in longitudinal alignment.
The upper portion 50 of controller 44 is provided with a lower set 62 and an upper set 64 of transversely extending inlets for the flow of liquid into passage 54. The inlets are preferably circular in cross section and the axis of each is spaced laterally from the axis of the passage 54. As shown, these inlets are tangent with the inner surface of the passage 54. Thus, the transversely extending walls 66 forming the inlets provide for directing the incoming fluid tangentially into the passage 54 and not into the longitudinal center of mass of the fluid passing through the passage 54. Thus, the momentum of the incoming fluid will urge the fluid, passing longitudinally through the passage 54, to circulate about the axis of the passage 54 and to vortex as it passes through the passage portion 56 and toward the throat 58. It will be clear that when the pasage 54 is not full of liquid, i.e. vapor has entered through the open top 68 of the upper portion 50, this vortical movement of the fluid will cause an elongated funnel, that is devoid of liquid, to be formed about the axis of the vortex, which axis extends longitudinally of the passage 54.
When the controller 44 is employed to control the flow from a container that contains volatile liquor, or liquor at the saturation temperature, and when the passage 54 is not full of liquid, the liquid forming the surface of the funnel, will cause increased liquor surface area, whereupon, increased vaporization or flashing will be induced. This vaporizing will increase the volume of vapor contained in the passage portion 54, approaching the throat 58, thereby proportionately decreasing the volume of liquid, resulting in a decreased mass flow rate. The decreased flow rate will reduce the vortical action causing the funnel to recede in the passage portion 56 which, in turn, will tend to increase the flow rate, resulting in increased vortical action and the above described process will be repeated.
The inlet 68 at the top of the passage 54 is sufficiently large to insure that fluid will be introduced into the passage 54 at as rapid a rate as it will pass through the throat 58, when the liquid level is above the top of the controller.
Due to the venturi effect of throat 58, the flow of liquid therethrough is accelerated, and, due to the continuing vortical movement of the liquid as it passes through the passage 60 and into the tube 46, a film of liquid is assured throughout the inner surface of the tube 46. 'lhis film provides maximum heat exchange between the liquor and the tube throughout the length thereof and maximum heat exchange with the environment surrounding the tube.
It will be understood that higher pressure prevails in chamber 38 than in tube 46, and it will be further understood that due to the design of the apparatus to which the control is applied, the level of liquid will always be above the inlet passage 62.
When such controllers are in parallel for a multiple effect, flash evaporator, they assure maximum flow of liquor relative to the vapor flow through the parallelly disposed tubes 46. They assure even flow to the parallelly disposed tubes and like flow of liquor throughout all tubes.
Too, when the controllers are employed in a multiple effect, flash evaporator, the throat 58 functions as a restrictor resulting in vaporization in the passages 60 and in the tubes 46. Since the swirling continues in passage 60 and tube 46, the cooled liquor on the interior of the tubes effects condensation of vapor thereabout, which vapor is emanating from the upstreamlike tubes.
The flow control characteristics of this controller 44 can be understood also by referring to FIG. 5, which graphically depicts the mass flow rate change at constant pressure as the liquid level is lowered below the top inlet 37 and also below the upper set of inlets 64. The upper portion 39 of the flow characteristics curve 4I depicts the flow rate through the controller as the liquid level is lowered to the same level as the inlet 68. When the liquid level is lowered below the level of the inlet 68, the incoming liquid will pass only through the sets 62 and 64 of inlets thereby inducing the above-described vortexing, funneling, vaporization and consequent flow rate reduction. This transition from somewhat steady flow to substantially decreased flow with only a small change in head is depicted at 43. It will be noted that the flow rate decreases rather slowly to 45 where the curve recedes slowly to 47. Thus, a desirable characteristic is provided in that the liquid level in the container from which the controller 44 is controlling the flow can fluctuate between the levels represented by the points 45 and 47 without significant flow rate changes.
Point 47 represents the level of the upper set of inlets 64 and it will be apparent that when the liquid level is lowered below that set of inlets, the entire fluid being controlled must pass through the lower set of inlets 62. Consequently, the above-described vortexing, funneling and vaporization takes place closer to the throat 58 than when the vortex is induced by inlets 62, thus causing the flow rate to decrease rapidly with decreasing head until the liquid level reaches the level represented by the point 5I. Again the curve 41 recedes slowly through point 53, thus providing a second desirable liquid level operating range.
When this device is used as a steam trap only, where tube 46 is not heated, the device could be cut off at any point below about outlet 60 and exhaust into almost any sized pipe or chamber. Since the tube 44 is flared gradually and progressively, outwardly, from the throat 58 to the outlet 84, the exiting fluid will be urged to flow adjacent the walls forming the pasage 60 rather than directly down the center of that passage and will continue to flow down the inner surface of the tube 46.
From the foregoing, it will be apparent that the controller 44 of this invention is of simple, sturdy construction and that it is inexpensive to produce. In addition, the controller provides reliable flow control and desirable flow characteristics. It will be readily apparent to those skilled in the art that this controller satisfies also the following criteria:
1. It operates over a wide range of flow rates, with or without level trays, and without an excessive passage of steam or the need of a large liquid head above the device. This minimizes liquor holdup, yet assures adequate feed to each tube. 2. It is the major pressure reducing device between effects in an evaporator to percent) and it utilizes this pressure drop to accelerate the fluid, thereby increasing the heat transfer rate to the fluid. 3. It maintains an even distribution of liquor over the entire inside surface of the evaporator tube to prevent drying and scale formation.
It will be readily apparent to those skilled in the art that another purpose is for transmitting fluid in equilibrium with its vapor from one container to another in such a manner as to maximize the ratio of liquid flow to vapor flow. Too, it will be readily understood by those skilled in the art that there is substantial freedom in the vertical positioning of the controller in that each will function satisfactorily any time the liquid level is above the inlet 62, although the inlet heights of the tube vary considerably. This feature renders it unnecessary to accurately level the surface, such as floors 39, from which the plurality of controllers are controlling flow. The controller of this invention is especially adaptable to be utilized in steam lines as a steam trap and also for controlling the flow from sequential stages of sea water conversion devices.
Referring now to the embodiment shown in FIGS. 6 and 7, superimposed containers are shown at 86 and 88, container 88 being disposed above container 86. Containers 86 and 88 are provided with bottoms 90 and 92, respectively. A controller 144 has a lower portion I50 including section lSI and portion 152, which are disposed in lower container 86. Portion I52 is downstream of section ISI. The section I51 is open at the bottom as at 168 and is provided with a longitudinally extending passage I54 which merges downstream with passage 156 in the upper portion which is disposed in container 88. This passage I56 merges with a throat 158, the latter being downstream of passage 156. The upper portion includes also a passage I60 downstream of the throat I58. The passage I60 leads to a tubelike tube 46.
In the embodiment shown in FIGS. 6 and 7, the lower por tion I50 includes a section 151 which surrounds the lower part of that portion and is provided with a closed bottom wall 153. As shown more clearly in FIG. 7, the section 151 is provided with a lower set 162 and an upper set I64 of passages for conducting liquor from the container 86 to the passage I54. These passages are disposed for directing liquor tangentially into passage I54 as explained with respect to passages 62 and 64 in the embodiment shown in FIGS. 2, 3 and 4.
The open top I55 of section I51 is disposed below the bottom 90 of container 86. A vapor inlet I57 is provided in the upper portion I50 below the top of section 15] and above the upper passages I64 for supplying vapor from the upper part of container 86 to the passage 154 when the level of liquid in the container falls below the open top of the section I51.
When the liquor level in container 86 is above the top of section l5I of portion I50, the passages have substantially no effect. However, when the liquor level in container 86 falls to below the top of section I51, but above tangentially disposed passages 164, all liquor passing to passage I54 from container 86 is through tangentially disposed passages 164 and I62, and, when the level in container 86 falls below passages I64, then all liquor will flow from the container 86 through tangentially disposed passages I62. The vortical movement imparted to the liquor in the passages 154 and I56, throat I58, passage I60 and tube 46, functions the same and achieves the results as explained heretofore with respect to the controller 44. Vapor is supplied to support the vortex through inlet 157. Also, the acceleration to the liquor, induced in the throat 158, has the same characteristic as explained heretofore with respect to throat 58, i.e. swirling of the liquor continues through passage I60 and against the interior of tube 46 providing intimate heat exchange between the liquor and the tube and between the tube and the surrounding environment.
1. The method of minimizing the flow of vaporizable liquor from a container, which method consists in:
A. introducing, into a tubular element having an inlet in the upper part thereof in open communication with the con tainer, liquor from the container in a manner to effect vortical movement of the liquor in the element below the inlet;
B. passing the liquor, while in the vortical movement state,
from the element toward and thereafter through a confining throat;
. C. conducting the liquor downstream from the throat.
2. The method of controlling the flow of vaporizable liquor from a container as defined in claim 1, characterized in that the container is above the throat.
3. The method of controlling the flow of vaporizable liquor from a container as defined in claim 1, characterized in that the container is below the throat.
4. The method of controlling the flow of vaporizable liquor from a container as defined in claim 1, characterized in that the introducing force creating the vortical movement is sufficient to maintain vortical movement throughout and downstream of the throat.
5. The method of controlling the flow of vaporizable liquor from a container as defined in claim I, characterized in that the conducting of the liquor downstream from the throat is through a progressively increasing area.
6. A combination comprising:
A. a container for volatile liquor;
B. a controller for minimizing the flow of vaporizable liquor from the container, said controller including:
i. a tube having:
a. a tubular portion extending into the container, said portion having an inlet in the upper part thereof in open communication with the container,
b. a tubular portion in the container downstream of the inlet, said latter portion having at least one passage leading to the interior thereof from the container. said passage having a surface for directing liquor tangentially into the latter portion for effecting vortical movement of the liquor in the latter portion,
c. a portion forming a throat disposed downstream from said passage for receiving liquor from the second mentioned portion C. means downstream of the throat for receiving liquor passing through the throat.
7. A combination as defined in claim 6, characterized in that the container lies above the throat.
8. A combination as defined in claim 6, characterized in that the container lies below the throat.
9. A combination as defined in claim 6, characterized in that the throat increases in cross section progressively downstream.
10. A combination as defined in claim 6, characterized in that the second mentioned tubular portion has a second passage disposed below the first mentioned passage, said second mentioned passage having a surface for directing the liquor tangentially to augment the effect of the first mentioned passage.
II. A combination as defined in claim 6, characterized in that the means (C) downstream of the throat is a tube.
11. A fluid flow controller for minimizing the flow of volatile liquor from a container, said controller comprising:
A. a tube having:
I. a tubular portion extending into the container, said portion having an inlet in the upper part thereof in open communication with the container;
2. a tubular portion extending into the container downstream of the inlet in the first mentioned portion, said second mentioned portion having at least one inlet leading thereto from the container, said latter inlet having a surface for directing liquor tangentially into the second mentioned portion for effecting vortical movement of the liquor in the second mentioned portion- 3. a portion forming a throat disposed downstream rom the second mentioned portion for receiving liquor therefrom 4. means downstream of the throat for receiving liquor passing through the throat.
13. A fluid flow controller as defined in claim 12, charac terized in that the container is above the throat.
l4. A fluid flow controller as defined in claim 12, characterized in that the container is below the throat.
IS. A fluid flow controller as defined in claim [2, characterized in that the means downstream of the throat is a tube.
16. A fluid flow controller as defined in claim [2, characterized in that the second mentioned tubular portion has a second passage disposed below the first mentioned passage, said second mentioned passage having a surface for directing the liquor tangentially to augment the efiect of the first mentioned passage.
17. A fluid flow controller for minimizing the flow of vaporizable liquor from a container to a tube with vortical movement of the liquor in the tube, said controller comprising:
A. a tube having:
l. a tubular portion extending into the container, said portion having an inlet in the upper part thereof in open communication with the container;
2. a tubular portion extending into the container downstream of the inlet in the first mentioned portion, said second mentioned portion having at least one inlet leading thereto from the container, said latter inlet having a surface for directing liquor tangentially into the second mentioned portion for effecting vortical movement in the second mentioned portion;
3. a portion forming a throat disposed downstream from the second mentioned portion for receiving liquor therefrom, the downstream portion of the throat being connected with the tube.
18. A fluid flow controller as defined in claim 17, characterized in that the throat increases in cross section progressively downstream.