US3445095A - Slotted tray for fractionating column and the like - Google Patents

Description

May 20, 1969 v. BRAUN T L ,4

SLOTTED TRAY FOR FRACTIONATING COLUMN AND THE LIKE v Filed Oct. 11. 1967 Sheet of 2 ,4' g Q 4 INVENTORS Masfimi/ 6/1700 W0 May 20, 1969 v, BRAUN ET AL 3,445,095

SLOTTED TRAY FOR FRACTIONATING COLUMN AND THE LIKE Sheet of 2 Filed OGt. 11, 1967 Zia 757701 grow; fi/a W526 INVENTORS United States Patent 3,445,095 SLOITED TRAY FOR FRACTIONATIN-G COLUMN AND THE LIKE Vlastimil Braun and Oto Vitek, Brno, Czechoslovakia,

assignors to CHEPOS, Zavody chemickho a potraviniifskho strojirenstvi, oborovy podnik, Brno, Czechoslovakia Filed Oct. 11, 1967, Ser. No. 674,406 Int. Cl. B01d 3/22 U.S. Cl. 261114 6 Claims ABSTRACT OF THE DISCLOSURE In a fractionating column or similar contact apparatus in which a rising vaporous and/or gaseous phase countercurrently meets a descending liquid phase, there are slotted trays and caps for the slots in the trays. The slots are elongated, and each cap which is formed and serves as a floating valve is to cover either a single slot or two or more longitudinally aligned slots. Each of the caps is movable from and toward the area of the respective tray, surrounding the respective slot or slots, and is centrally provided with lengthwise extending continued rib means which depends from the underside of the cap downwardly toward the respective slot or slots. The rib means is spacedly provided with means to engage the underside of the tray, when the respective cap moves upwardly, and thus to limit the upward movement of the cap.

Background of the invention This invention relates to a slotted tray for fractionating columns and the like, and is to effect intimate contact between rising vapors and/or gases and a heavier descending liquid. The tray is provided with a plurality of elongated, ordinarily parallel, slots which are covered by elongated caps. A cap covers either a single slot or two or more longitudinally aligned slots.

Such trays are particularly suitable in countercurrent operations in rectification, disillation, absorption columns and similar apparatus.

The primary object of this invention is to generally improve slotted trays for fractionating columns and the like, to simplify and strengthen their construction, to cheapen their manufacture, assembly, and maintenance, and to render them more eflicient and reliable.

Important objects of our present invention center about a tray which will ensure even distribution of both the vaporous and/or gaseous phase and the liquid phase for effective heat and intimate mass transfer and will improve the efficiency of the tray, enhance the capacity of a column equipped with the tray of the invention, and achieve a wide flexibility of the column within a broad range of practical services. The invention aims at securing a more uniform efiiciency of the tray, and more intimate contact between the countercurrently moving two phases, across the whole tray surface.

One object of the invention is to ensure, along with a proper distribution of the liquid on the tray, a proper hydraulic balance and thus to substantially reduce the hydraulic gradient.

A further object of our invention is to provide a tray that is free of obstructions to the liquid flow and will lessen sedimentation of impurities and the necessity for the provision of frequent cleaning intervals, especially in services in which there is a tendency for solid particles to settle.

A copending application of ours, Ser. No. 464,982, filed June 28, 1965, deals with a slotted tray of the referred to type. The cap disclosed in said copending application is provided with means depending from the under- 3,445,095 Patented May 20, 1969 side of the cap and extending downwardly to or through the slot or slots in the tray, which is or which are covered by the cap. The depending means has side extensions which extend crosswise with respect to the depending means and are spaced from the underside of the tray so that such extensions may engage the underside of the tray and thereby limit the upward movement of the cap when lifted by rising vapors and/or gases.

In the construction of the tray of the aforementioned copending application, the depending means consists either of two parallel series of spaced members, with the members of one series being staggered with respect to the members of the other series, or of a single series of spaced members.

While in either of the two embodiments disclosed in our earlier application the depending means is constituted by individual spacedly arranged members, the present in vention provides for each cap a single elongated and continued depending member. Further, in either of the referred to and previously disclosed two embodiments the depending members are formed as integral parts of the main body of the cap itself, whereas the depending member of the present invention is formed as an added part. Still further objects of our invention are, therefore, a tray which can be provided with much narrower slots than heretofore, and a cap that, too, can be made much narrower and of light-weight material and will nevertheless be elfective and rigid.

Additional objects of the invention will be apparent from the following description.

Summary of the invention The invention provides, as appears indicated hereinbefore, a single elongated and uninterrupted or continued depending member rather than a series or two of individual spacedly arranged depending members. The depending member according to the invention is of a riblike formation and serves the purpose of reinforcing the caps and of rendering a tray and its caps more efiicient and more economical.

Broadly, the invention consists in tray members having elongated slots and in elongated caps, the latter being mounted to varyingly cover the slots. Each cap covers either a single slot or more than one slot, with such plurality of slots being longitudinally aligned, and is reciprocally movable relative to the area of the respective tray member, that surrounds the respective slot. Each of the caps includes opposite side portions above the top of the respective tray member, a single elongated and continued depending member, and abutment members. The depending member is centrally arranged on the underside of the cap to extend lengthwise and downwardly toward the slot underneath. The abutment members are longitudinally spacedly secured to the depending member and limit the upward movement of the respective cap away from the referred to tray area, when lifted by a rising vaporous and/or gaseous phase.

If a cap is to cover more than a single slot, it is, however, necessary to divide the depending member accordingly. For instance, if a cap covers two longitudinally aligned slots, two separate aligned depending members are provided. The spacing between the two members corresponds to the end-to-end distance between the slots.

Brief description of the drawings Other features and many of the attendant advantages of the invention will readily be appreciated as the same becomes better understood by reference to the detailed description of preferred embodiments, following further below, when considered in connection with the accompanying drawings in which:

FIG. 1 is a plan view of a slotted tray and of caps covering the slots in the tray, the tray and caps embodying features of the invention, and the tray being show in a fractionating column;

FIG. 2 shows two such trays one above the other, the slots and caps of one of the trays appearing turned by 90 with respect to the slots and caps of the other tray, the trays and caps being shown in cross section and a side view, respectively;

FIG. 3 is a fragmentary cross section, on an enlarged scale, of a tray, showing a single cap;

FIG. 4 is similar to FIG. 3, showing the cap in its lifted rather than in its rest position;

FIG. 5 shows a modified cap in plan to enlarged scale;

FIG. 6 is a fragmentary oblique representation of a tray and cap of FIGS. 1 to 4; and

FIG. 7 is a fragmentary cross section of a tray, showing another modified cap.

Description of preferred embodiments Referring to the drawings in greater detail now, and initially to FIGS. 1 and 2, FIG. 1 shows a slotted tray 1 in a fractionating column 6, and FIG. 2 shows at a sufficient distance from each other two adjacent trays 1 out of a greater number of trays now shown. In FIG. 1, the tray is shown to be provided with seven slots which are designated 5 S S S S S S The slots in one of the two trays of FIG. 2 and thus the caps 2 which cover the slots in said one tray appear angularly displaced with respect to the slots and caps of the other tray. The exemplary displacement shown in FIG. 2 is one of 90.

It is seen that the slots although of different lengths, are all elongated and that the caps 2 are of corresponding lengths.

Each cap 2 consists of an elongated cylindrically bent sheet strip, which is best seen in FIGS. 3 and 4, from the underside of which depends a riblike member 3 that extends downwardly toward the slot underneath, and lengthwise substantially throughout the length of the respective cap. Each rib or depending member supports a plurality of abutment members 4. From FIG. 1 it will be seen that each of the two outermost caps which cover the slots S S and each of the two caps next to the outermost ones, which cover the slots S S has two abutment members 4, whereas the cap along the center line and the two caps to the left and right of the center cap, which cover the slots S S S have three abutment members 4. The latter three caps are of identical length.

The abutment member 4 of FIGS. 1 to 6 is formed as a bifurcated flat body having two lateral extensions 4 that form shoulders at 4" (see especially FIG. 3). The rib 3 is received between the two branches 4a, 4a of the abutment member 4 and is fastened to the latter.

FIG. 3 shows a cap 2 in its rest position, with side portions 2 of the cap touching the top of the tray 1 and the lateral extensions 4' of the abutment member 4 being spaced from the underside of the tray.

The side portions 2' of each cap have along both of their edges spacedly provided cutouts C. The cutouts along one of the edges are, as can be seen from FIG. 1, staggered with respect to the cutouts along the other edge. Each cutout is to serve as a passage P for liquid to trickle therethrough in downward direction (see FIG. 4).

When the caps are lifted by vapor or gas pressure, they may assume the uppermost position shown in FIG. 4. This position is determined by the distance between the underside of the tray and the shoulders 4". In FIG. 4, the two shoulders 4" are in actual contact with the underside of the tray. With the cap raised above the tray, there are passages P formed between the top of the tray and the side portions 2' of the cap.

As vapors and gases collect below the trays, they start lifting the caps. First, vapors and gases escape along the ribs 3 and through narrow gaps between the top of the trays and the edges of the side portions 2', and as the caps rise more and more, the narrow gaps widen and form in the end the Wide passages P. In FIG. 4, the flow of the liquid is shown in dashed lines, and the flow of the ascending phase in dotted lines. Liquid collected on the trays thus receives a turbulent movement, which results in an intimate contact of the two phases.

While the slots in the trays 1 have sharp-cornered ends, a slot Sa in a tray 1a is shown in FIG. 5 as having an end 9 forming two rectangular corners, and a rounded end 10. The cap 2a of FIG. 5 has both cornered cutouts 7 and rounded cutouts 8, rather than exclusively cornered cutouts like the cutouts C in FIGS. 1 to 4. Rounded slot ends such as the end 10 and rounded cutouts such as the cutout 8 have an economical effect in lengthening the effective working periods of cutting tools.

In FIG. 7, a modified abutment member 5 is shown, which has, in addition to lateral extensions 5' that are to contact the tray 1 from below, lateral extensions 5a that lie on top of the tray when the abutment member is in its lowermost position. The extensions 5' act exactly as the extensions 4' of the abutment members 4 of FIGS. 1 to 6, While the extensions 5a are effective in holding the cap 2 in its rest position such distance away from the top of the tray 1 as will prevent the edges of the side portions 2' to contact, and possibly stick to, the tray when the latter during operation becomes covered with sticky asphaltic substances.

A d van rages It is believed that the construction and operation of the tray for practicing the invention, and the many advantages thereof, will be fully understood from the foregoing detailed description. Some of these advantages are reviewed hereinafter. The construction of the cap of the invention, which provides for the longitudinally extending reinforcing rib, makes it possible to narrow substantially both the slots and caps and to achieve a more intimate and a more uniform contact over the whole of the surfaces of the trays. The reinforced cap according to the invention permits relatively large cutouts along the edges of the side portions of the caps and does not require great lifting heights for the caps. The gaseous and liquid phases are more finely divided, which promotes heat and mass transfer. The cap is of utmost simplicity, which reduces manufacturing, assembling, and maintaining costs. The slotted tray and the cap of the invention are the most economical column equipment as yet developed for distillation, absorption, stripping, and similar purposes.

We claim:

1. In a fractionating column or the like for effecting intimate contact between a rising vaporous and/ or gaseous phase and a descending heavier liquid phase,

(a) slotted tray members, the slots in the tray members being elongated,

(b) elongated caps mounted to varyingly cover said slots, each of said caps having a longitudinal axis and a lower surface and being reciprocally movable relative to the respective slot,

(c) a rib member associated with each of said caps, extending longitudinally, and uninterruptedly and substantially throughout the length, of the respective cap, said rib member extending from said lower surface toward the respective slot,

((1) abutment means provided on said rib member, said abutment means being constituted by longitudinally spaced abutment members, portions of each of said abutment members being spaced from the underside of the respective tray member and being adapted to engage said underside and to limit the upward movement of the respective cap.

2. The column according to claim 1, each of said abutment members including a flat body extending substantially transversely of the elongation of the respective cap.

3. The column according to claim 1, each of said abutment members including a bifurcated flat body having a pair of lateral extensions, portions of said rib member being received in the bifurcation of a plurality of abutment members.

4. The column according to claim 1, each of said abutment members including a bifurcated fiat body having two spaced pairs of lateral extensions, portions of said rib member being received in the bifurcation of a plurality of abutment members.

5. The column according to claim 1, wherein each of said caps has opposite side portions above the respective tray member and said side portions have two longitudinally extending edges and spacedly arranged cutouts along said edges.

6. The column according to claim 5, wherein the cutouts along one of said edges are staggered with respect to the cutouts along the other edge.

References Cited UNITED STATES PATENTS 9/1960 Nutter 261--114 5/1961 Eld et a1. 261114 FRANK W. LUTTER, Primary Examiner.

S. H. MARKOWITZ, Assistant Examiner.

US. Cl. X.R.

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