US2857055A - Devices for regulating liquid levels in liquid accumulation vessels - Google Patents

Description

United States atent- O "DEVICES FOR REGULATINGLIQUD LEVELS IN LIQUID'ACCUMULATION VESSELS Clarence 0. Glasgow, Tulsa, 01:121., assignor to National Tank Company, Tulsa, Okla a corporation of Nevada Continuation of application Serial No. 419,220, March This application June 13, 1955, Serial No.

4 Claims. (Cl. 210-540) '-gas and liquid hydrocarbons being drawn oif through a common outlet.

It is a particular object of-this invention to provide a device ofthe character described having improved means for regulatingand adjusting within a closed pressure vessel the elevation ofa body of liquid hydrocarbons within such vessel, coupled with the simultaneous regulation or adjustment of the water level therein.

Yet another object of the invention is to provide an improved device of the character described whereby the elevation of the surface of a liquid hydrocarbon stratum within a pressure vessel may be adjusted from the exterior ofthe vessel quickly and readily, and with considerable "exactness.

A further object of the invention is to provide an overflowweir structure for liquid outlets from pressure vessels which may be adjusted from the exterior of the vessel without depressuring orv opening the vessel or in any way interfering with or interrupting the operation being carried out in the vessel.

It has been observed that the specific gravity of'the water separated in pressure vessels as herein set forth may be greater than 1.0, and that the specific gravity of the separated liquid hydrocarbons may "be quite low, especially in high pressure vessels. Probably, the latter is due to the solution of gas in the hydrocarbons.

In any event, it has been discovered that variation of the waterlevel in the vessel causes an inordinately large change in the hydrocarbon level, but that variation of the hydrocarbon level results in a proportionately small change in thewater level.

Hence, it is a particular object of the invention to provide an improved device of the character described where- .in external adjustment of the hydrocarbon level, as conpressure vessel having incorporated therein an adjustable "ice . 2 liquid outlet structure constructed in -accordance"with this invention,

Fig. 2 is an enlarged, fragmentary,-vertical;sectional view illustrating the-adjusting means, and

Fig. 3 is a transverse,' horizontal, settiofial-view-taken' upon the line 3-3='of Fig. 1.

This application-is a -continuationof my -copending application Serial No; 419,220; filed March 29,- 1954, n'ow abandoned.

While the invention His applicabletowmany types"of liquid accumulating vessels, 'ithas been illustrated in conjunction with-useina simple-type "of separating device wherein water is separated from a well flow streamcontaining water,- liquid hydroe-arbons;- and-naturalrgas. The structure includes 'an elongate; horizontal tank or vessel ltlhaving one end closed byva dished -inlet--head-11 through whichan inlet conductorlz entersthe vessel. There is provided at vthe innerend of the fluid iulet 12 a simpleseparating structure-13r of the type conventionsally used in such structures and whichdncludes -a box;'14

supported 1 upon gusset plates 15: and carrying a plurality .of vertically-extending vanes or bafiles 16 arrange'd -in .spaced' and staggered-relationship inorder to reducethe velocity of entering fluids and: prevent :theprojection-of large .bodies of liquid lengthwise of=-the vessel l0. The .fiow. streams handled in this partciular' type of vessel are readily separated-upon. a reduction of velocity and stratify within the vesselinto a lower-waterlevel 17, a stratum 18 of liquid. hydrocarbons,-suchas petroleum v distillate,

floating-upon the water layer,: and agas space or. stratum 19 in'the-upper. portion. ofthe vessel.

The opposite end of the vessel 10- is also ClOSGd'abY a dishedhead 20 whichcarries a float-mechanism-"Zl of any suitable or desirable type-upon which there is supported, within the vessel 10 and adjacent the. head 20, a float 22 responsive to the rising ofwater-within the vessel -to actuate'the mechanism Zl-and thereby operate a drain valve .(not sho'wn) which controls thedischarge of water. from 'thevessel through a water outletI23 'leading from the lower portion thereof. Interiorly of the'vessel 10, "there is provided an upstanding baffle-or weirplate extending upwardly from the bottom of the 'vessel'10 to aj'point adjacent themiddle portion thereof, 'and over the upper .edge of which water mayjspillinto the compartment 25 between 'saidjpar'tition and thehead 20, andwithinwhich thelfloat 22' is disposed. Toexcludetheliquid hydrocarbons from the partition 24, there is 'p'rovidedla'n intermediate bafile 26 positioned closely adjacent the ba'flle 24 so as to provide a'fiow space'27 therebetween, the'upp'er edge of thebaflle 26 being spaced from theupper wall of the'vessel'ltl to permit "an equalizing gas flowthereover, and the lower, edge of the 'bafile 'zo'being spaced from the bottom of the vessel 10 to permit the'flow'of water'thereunder. The interface 28 between the water and hydrocarbonlayers intersects the baflle26, and hence, only water is permitted tofiow-urfder thepartition 26, upwardly-through the space 27, and over'the upper edge of-the partition-24 into-the sump'25. There may also be The vessel maytalso carry a'plurality 'of=couplings'or* fittings :30 in: its upper and lowerwalls forthe reception of 3 pressure safety valves, drain valves, thermometers, pressure gauges, and the like.

The structure thus far described is relatively conventional in the art and no claim thereto is made herein except in conjunction with the liquid hydrocarbon and gas discharge structure to be described hereinafter.

For discharging liquid hydrocarbons and gas from the vessel 10, there is provided an outlet pipe or conductor 31 extending downwardly into the vessel and having its inner portion extending vertically within the vessel and terminating at a point spaced between the upper and lower walls of the vessel. An open inlet means in the form of a circular weir or weir cup 32 is received upon the inner end of the conductor 31, and is adjustable vertically thereon. The weir structure 32 includes a cylindrical outer wall 33 joined by a closed bottom 34 and having a plurality of radial internal ribs or guides 35 extending longitudinally of the cup and spacing the latter in vertical slidable relationship upon the conductor 31. The vessel is provided in its lower wall with a screw-threaded collar 36 within which there is mounted an externally screwdhreaded tube 37 extending upwardly into the interior of the vessel 10. The tube 37 is formed with an axial bore 38 through which an elongate rod 39 extends, the lower portion of the bore being screwthreaded at 40 and receiving screw threads 41 provided on the rod 39. The lower end of the rod 39 projects exteriorly of the vessel 10 and below the lower end of the tube 37, a wrench head 42 or other suitable structure being provided upon the lower end of the rod whereby the same may be turned or rotated as desired and screwed upwardly and downwardly within the tube 37. There is also provided in the wall of the bore 38 and adjacent the upper end of the tube 37 an internal annular groove 43 having therein a sealing O-ring 44 which embraces the rod 39 and seals the space between said rod and the wall of the bore 38. The upper extremity of the rod 39 is pivotally pinned within a short collar 45 depending from the bottom 34 of the weir structure 32.

From the foregoing, it is quite apparent that an operator may adjust the weir cup 32 vertically within the vessel 10 by revolving the rod 39 in any suitable fashion and causing the same to move upwardly or downwardly within the tube 37. Such adjustments or manipulation of the vertical elevation of the weir cup 32 within the vessel may be carried out at any time without opening the vessel 10 or releasing pressure therefrom, and in no way interferes with or hampers the continuous operation of the separator vessel 10. The pivotal connection of the rod 39 to the weir cup makes allowance for any slight misalignments of these two elements.

In the operation of the described structure, a well fluid enters the vessel 10 through the inlet 12, with dispersion and velocity reduction of the fluid stream occurring in the unit 13. The stream separates and stratifies due to the reduced velocity thereof, into water and liquid hydrocarbon layers surmounted by a stratum of gas. The water flows under the partition 26 and over the partition 24 into the sump 25 for discharge through the outlet pipe 23 in accordance with the rate at which the water accumulates in the sump 25 and lifts the float 22 to actuate the mechanism 21. The liquid hydrocarbons accumulate in a stratum above the layer of water and overflow over the upper edge of the cylinder 33 into the cup-like weir structure 32, and under the impetus of the pressure exerted by the gas layer, are driven along with the gas upwardly through the outlet conductor 31. Since a vessel of this type may operate under a pressure of several hundred or several thousand pounds per square inch, adequate force is available for driving the gas and liquid hydrocarbons upwardly through the outlet conductor.

It is to be noted that the interface 28 between the and the liquid hydrocarbons, and further determined by the relative difference in elevations between the upper edge of the partition 24 and the upper edge of the weir cup 32. The upper edge of the partition 24 being fixed, vertical adjustment of the cup 32 will raise and lower the interface 28 as desired and provide for the maintenance of the interface at any desired elevation. Of course, the interface is normally maintained in a horizontal plane intersecting the baflile 26 to prevent loss of hydrocarbons through the outlet 23, but since the clearance between the lower edge of the partition 26 and the bottom of the vessel 10 need not be large, wide flexibility in the vertical adjustment of the liquid hydrocarbon layer and the horizontal plane of the interface is made possible.

The invention has especially beneficial results in the adjusting and regulation of a vessel of the type described in order to maintain therein the various liquid levels at the desired elevations. Further, the invention eliminates the need for exacting manufacturing procedures in fabricating the separator vessel and in positioning very precisely therein the upper edges of the various weir elements since the permissible subsequent adjustment of one of the weir elements makes provision for maintenance of proper liquid and interface levels. Adjustment of the liquid layerand interface surfaces during operation of the vessel is made possible whereby the levels may be set precisely at the points desired.

As pointed out hereinbefore, the relative densities of the hydrocarbon and water strata may differ considerably in this type of unit, and the water may be much heavier than the hydrocarbon. Consequently, a small adjustment of the water level at the partition 24 in accordance with the usual practice would be reflected in a large change in the hydrocarbon level and the interface level. This has been found, in instances, to allow hydrocarbon to flow into the water outlet Zone, to isolate the hydrocarbon from its outlet, or to flood the hydrocarbon outlet.

In the present structure, the hydrocarbon level, rather than the water level, is adjusted, and the elimination of the foregoing malfunctions is obtained, along with more exact and controllable setting of the various levels.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

l. A liquid and gas separating structure including, a pressure vessel having a fluid inlet, a first liquid discharge from the vessel, a support rod extending upwardly into the vessel through the bottom wall thereof and mounted in said wall for vertical adjustment, an open top weir cup supported in the vessel by the support rod, and a second liquid discharge conductor fixed in the vessel and having its inlet end extending vertically downwardly into the Weir cup, the weir cup being vertically movable with respect to the inlet end of the discharge conductor by vertical adjustment of the support rod.

2. A liquid and gas separating structure including, a pressure vessel having a fluid inlet, a first liquid discharge from the vessel, a support rod extending upwardly into the vessel through the bottom wall thereof and mounted in said wall for vertical adjustment, an open top weir cup supported in the vessel by the support rod, and pivotally attached thereto, and a second liquid discharge conductor fixed in the vessel and 'having its inlet end extending vertically downwardly into the weir cup, the weir cup being vertically movable with respect to the inlet end of the discharge conductor by vertical adjustment of the support rod.

3. A liquid and gas separating structure as set forth in claim 1, and a collar extending through the bottom wall of the vessel, a tube in the collar projecting into the vessel, the support rod being received in. screw- 5 therein by rotation, and an O-ring seal between the tube and the rod.

4. A liquid and gas separating structure as set forth in claim 1 wherein the open top weir cup is vertically slidable on the inlet end of the discharge conductor and is provided with closed bottom and internal guides spacing it from said inlet end of the conductor.

306,171 Moseley Oct. 7, 1884 6 Edson Dec. 24, 1901 Maranville Feb. 2, 1909 Baldwin et al Dec. 1, 1914 Bateman Nov. 4, 1924 Lovelady Feb. 29, 1944 Walker J an. 4, 1949 Hayes et a1 Nov. 25, 1952 Van Houton et a1 Mar. 2, 1954 Reid June 15, 1954

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