US2394679A - Downspout for bubble trays - Google Patents

Description

DowNsPouT FOR BUBBLE Tmws Filed June 5, 1944 Patented Feb. v12, 1946 DoWNsPoU'r Fon BUBBLE 'raars Clarence G. Gerliold, Chicago, Ill., assigner to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application June 5, 1944, Serial No. 538,833 4 claims. (ci. zei-n4) This application is a continuation-impart of application Serial- No. 510,284, filed November 15,

. This invention relates to an improved form of downspout for bubble trays and the like. More specifically it is concerned with a means for increasing the capacity of given sized downspouts by a novel arrangement of apparatus.

The conventional downspout used'in fractionating columns and the like employing bubble trays is merely an open-ended conduit extending' through the deck of the tray and adapted t carry liquid from a point above the trayto a point below tional view of a portion of a bubble tower in which the features of the invention are embodied.

In the drawing, l denotes the -outer shell of the bubble tower within which are disposed at vertically spaced intervals bubble trays 2. The y v bubble trays are provided with a plurality of the tray. In conventional apparatus these downspouts when designed to adequately accommodate the downward moving liquid in the column occupy a considerable portion of the tray area. The tray area unoccupied by downspouts is generally provided with a plurality of risersv and bubble caps by means of which contact between gases and liquids is accomplished. It is therefore, obvious A that as much of the bubble tray area as can be provided with bubble caps is desirable in order to utilize to the utmost the full tionating column.

The present invention by providing a means for increasing the capacity of downspouts provides a more eilicient contacting means because a higher proportion of the bubble tray areais actually employable for contacting the liquid and gaseous materials.

In some cases where 'fractionating columns have been erected following conventional design, it has been found that the downspouts are inadequate to convey the normal'ow of liquid down the column. This results in flooding of the colimns and cons'equently'very unbalanced operaion.

The present invention may be advantageously adapted to these particular situations to overcome the difficulties due to flooding of the columns.

Briefly the present invention comprises in combination with a bubble tray downspout, a closure means at the upper end of said downspout, said downspout being provided with at least one inlet port at the normal liquid level carried on the bubble tray, and an open-ended conduit extending from a point above said closure means through the latter to a point within saidv downspout a spaced distance above the lower end thereof.

capacity of the fracrisers 3 eachof which is surmounted by a bubble cap 4 which is held in place by means of hold down bar 5, or by any other conventional means.

Member 6 is an elongated conduit which forms .the main portion of thedownspout and is supported by welding or other suitable means from bubble tray 2. Conduit 8 extends from a point immediately below the normal liquid level to be maintained on the tray, through the`\tray to a point above the next lowermost tray but below the normal liquid level to .be maintained thereon. At the upper end of conduit 8 is positioned a closure means comprising plate 1 and supporting webs 8. Centrally disposed within conduit 6 and extending from a pointspaced from the lower end of conduit 6 through plate 1 to a point above the latter is an open-ended conduit 9. lThe function of this latter conduit will be hereinafter described.

In-operation the downspout will function as follows:

When the liquid level is at the position indicated by broken line I0 the head of liquid above the upper end of conduit 6 which acts as a weir is equal to h1. This head of liquid will cause a particular quantity of material to flow into the annular space between conduits s andv 9 in the downspout. signed that the quantity of liquid flowing due to head h1 is less thanthe normal downward iiow of liquid through the columns. It is, therefore. apparent that the liquid level on the tray will tend to increase until it reaches the level indi cated by broken line Il. When this occurs the ports provided between the upper end of conduit 6 and plate 1 are completely covered with liquid matic drawing which shows a sectional elevapreventing the passage of any gases into the annular space in the downspout. When this occurs. the entire annular space fills with liquid and immediately the effective head on the liquid on the tray becomes equivalent to ha.' This increase ln effective head will greatly increase the flow of liquid from the tray into the downspout andrapidly bring the level down to the level indicated `bybroken line l0. As the column continues in operation the liquid level will fluctuate between the two levels indicated by broken lines ID and il. Entrained gases or vapors inthe liquid ilowing through the downspout are separated therefrom in the section below conduit 9 and pass up- However, the downspout is so dewardly therethrough 'to enter the vapor space above the liquid level on the tray.

In order that the full effective head, ha. be applied to induce ilow of liquid through the downcomer when the liquid level is in position Il.

` it is necessary that any Gases or vapors remaining in the downcomer be swept from it`. 'I'his in turn necessitates the condition that the rate '.of liquid flow down the downcomer relative to its cross section must be such that the liquid will fill the downcomer. While the exact dimensions necessary to bring about this condition depend to some extent onv the details lof fthe design of the downcomer, it is generally true that the liquid velocity will be 'suillcient tol illl the downcoiner if the cross sectional area of the portion conilned between conduits 6 and 9 is equal to,l or less than, the area of the opening between the'downcomer 6 and the plate through which they liquid flows.

I claim as my invention:

.1. In combination with a bubble tray down-v spout, a closure means at the upper end of said downspout, said downspout being provided with at least one inlet port at the normal liquid level carried on the bubble tray andan open-ended conduit extending from a point above said closure means through the latter to s point wams said downspout a spaced distance above the lower end ther/eci. y

2. In combination with a bubble tray downspout, a closure means at the upper end o! said -downspout, said closure means being spaced from the upper end of said downspout to form an inlet port therewith -at the normal liquid level carried on the bubbieltray, and an open-ended conduit extending from a point abovesaid closure means through the latter to a point within said downspout a, spaced distance above the lower end.

portion of the downspout conilned between said downspout and said conduit is not greater than the area of said inlet port. Y J CLAREN CE c+. Gannon).

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