US2351850A - Inverted siphon drain for tank roofs - Google Patents

Description

June 20, 1944. J. H. WIGGINS INVERTED SIPHON DRAIN FOR TANK ROOFS Filed Feb. '15, 1943 IN VEN TOR JOHN H. WlGG/NS Patented June 20, 1944 UNITED STATES PATENT QFF'ICE INVERTEl) SIPHON DRAIN FOR. TANK ROOFS John H. Wiggins, omea o, Ill. Application February 15, 1943, Serial No. 475,927-

(c1.'1s2 v-) Claims.

This invention relates to drains for removin water from the roofs or top of gas and/or liquid storage tanks, and particularly inverted siphon drains for floating roofs and breather type roofs of the kind -now used extensively on tanks in which gases, gasoline and crude oilare stored.

One objectionable feature or characteristic of the conventional tank roof inverted siphon drain is that it cannot be cleaned, inspected, or re.- paired while the tank is in normal operation, due to the fact that partsof the drain which are located on the underside of the roof are not accessible until after a screw-threaded joint has been disconnectedso astoenable the parts of the drain to be drawn upwardly through an opening in the roof.

The main object of my invention is to provide an inverted siphon roof drain of novel construction whose'partsare accessible from the top side of the roof for inspection, cleaning, or replacement, when the tank is innorm'al operation, i. e., in the case of a floating roof when the roof is supported by or floating on the liquid in the tank, and in the case of a breather type roof, when the tank is under pressure.

-Another object'is to provide a tank roofinverted siphondrain," in which water may safely be used to constitute the liquid sealing medium of the drain, due to the fact-that the drain is of such construction or design that at freezing temperatures the sealing Water-can freezesol-id; without breaking or cracking-the parts of the drain,

and when the temperature moderates, said-water will melt and again function as a liquid sealing medium for-the drain And still anotherobject ofmy invention is-to provide a tank roof inverted drain that is equipped with a removable sealing member or balfle, andmeans whereby the operation of removing said sealing member automatically closes the discharge pipe or outlet or the drain, and the operation of restoring said sealingmember automatically opens said discharge pipe oroutlet.

Other objects and desirable features of my invention will be hereinafter pointed out.

. Figure l of the. drawingis-a. fragmentary top plan view of a. floating tank roof equipped with my improved drain, showing the drainin horizontal sectionon theline 1-! of. Figure 2.

Figure .2 is a vertical sectional. view of said drain,.taken on the line 2:-2'of Figure 1; and

, Figure 3 is a diagrammatic view, illustrating in transverse. cross-section,- the tank,-=the floating roof, and the drain which removes rain or-snow waterirom the .top side ointhe rooft In Figure 3 of the drawing, A designates a-tank that is used to store-gasoline or oil, and B desi nates a floating roof thatis adapted-to cover and be supported by the gasoline oroil a: in said tank.

- My invention consists of a double inverted siphon drain that is used to'carry off rain water or snow water from the top side of the roof B and discharge said water downwardly into the oil 1' in the tank A. Said drain comprises a receptacle or tub C carried by the roof'B and arranged so that water which falls onor-collects on the roof can flow or drain into. the open upper end of said receptacle, a tubular outlet or discharge pipe D at the lower end of the receptacle C through which water escapes from-- said receptacle and flows downwardly into the body of-oil a: on which the roof floats, anda sealing'member or baffle E removably mounted in the receptacle C and 'accessible from the top side of the roof, the lower end portion of said baflie E being submerged in a liquid sealing medium y in the receptacle C.

As shown in Figures 1 and 2, the receptacle C, which is tub-shaped in general form or outline, tapers inwardly from its upper to its lower end, and is rectangular-shaped in horizontal cross section, said receptacle being-provided at itsupper end with a laterally-projecting flange I that is attached to the roofB in concentric relationship with a drain hole. 2 in said'roof. The outlet or discharge pip D of the drain is formed by an open-ended, vertically-disposed, tubular member that is rigidly attached to the bottom 3 of the receptacle C, the upper end of said discharge pipe terminating some distance above the bottom 3 of said receptacle. The sealing member or bafile E is removablymounted. in the receptacle C, and is arranged between the inlet at the upper end of said receptacle and the-discharge pipe or outlet D of the. drain. Said baffle or sealing member E conforms approximatelyto the shape of the side wall 4 of the. receptacle-C and is so proportioned with relation to said receptacle, that when said baffle E is in its operative: position, shown in Figure 2, there is a tall, relatively narrow slot or space between the side Wall 4 of the receptacle C and the side wall portion of said bafile. The open lower end of the baffle E is maintained in spaced relationship with the bottom 3 of the receptacle C by any-suitable means, such, for example, as by legstizat the lower end of the side wall portion of the baflleE, Whenrny improved drain is designed for use on a floating tank roof, it is not necessaryth'at' the upper end of the tubular baflle or-seal-ing-member E beclosed, but

55, inorder to reduce evaporation losses; I prefer to arrange a removable cover or closure F in the upper end portion of the baflie E. The removable closure F, shown in Figure 2, preferably has a sliding fit with the upper end portion of the sealing member E and is made of relatively great length or depth, so as to minimize evaporation losses.

Before. the tank is filled with oil, gasoline or other liquid, a liquid sealing medium 11 preferably water, is introduced into. the receptacle C, so as to fill the lower. end portion of said receptacle up to the top edge or upper end of the outlet or discharge pipe D of the drain. Thereafter, the baffle or sealing member E is introduced into the receptacle.C, so as to form 'a' baflie between the discharge pipe D and the it can be cleaned, inspected, or repaired, in the case of a floating roof, while the roof is floating on the liquid in the tank, and in the case of a breather type roof while the tank is under pressure. All that is necessary in the event inspection, cleaning or repair of the drain becomes necessary, is to close the outlet or discharge pipe D of the drain and then lift the baflie or sealing member E upwardly out of the receptacle C. Various means can be usedto close the discharge pipe D whenthe baflieE is .to be removed. One means that can be employed for this purpose, is

any suitable kind of a plug that can be inserted in the upper end of the discharge pipe D, after suflicient oil has been introduced intothe tank to cause the roof B to start to float, oil will flow upwardly through the discharge pipe D of the drain and fill-theupperv portion of the sealing member Eabove the level of the liquidsealing medium y, therebydepressing or lowering the level ofthe columnofseafing Water in the space between the discharge pipeD and the side wall portion of the baflleE, and raising or increasing the level of the column of sealing water in the space between the side wall portion of the bafiie E and the sidewall 4 of the receptacle C. By the time sufficient oil has been introduced, into the tank to float the roof B, or-cause said roof to beentirely supported by the-oil in the tank- A, the column formedby theysealing water balancesthe lighter specific-gravity. oil, and the liquid sealing-medium y remains in substantially the positionshown in Figure 2, wherein the heavy horizontal lines y designatethe liquid sealing medium, and the lighter horizontal broken lines designated by the reference character :0, represent the oil from the tank that has-backed'up into the .bailie E through the discharge pipe D and which floats on the liquidsealing medium 3! that previously wasintroduced into the receptacle C. At the firstrain, the rain water escapes from the top side of the roof andenters the space or slot between the side .wall 4 of the receptacleq and the side wall portion of the baille E, thereby causing the sealing water y in the space between the discharge pipeD and the side Wall, portion of said baflle to rise, with the result that some of thewater overflows the top edge of the discharge pipe D and escapes downwardly through same into the body of oil on which the roof floats. The area of. thespace between the discharge pipe D and the side wall portion of; the baffle E is preferably madethree or fourtimes the area of the narrow slot between the sidewall 4 of the receptacle C, and-the side wall portion of the baflie E, so that one inch of evaporation (say, during a long dry spell) from the watersurfacein said narrow slot, will usually be only one-third to one-fourthof the replenishing supply of water in the space between the discharge pipe D and the-side wall portion of the bailleE- 1 H One of themain advantages of my improved drain is that it permits water to be used as the liquid sealing medium of the drain, because the thin column of water in the tall, narrow, tubular space between the baflle and'the, side wall 4 of the receptacle 0 and the shallow puddle of water in the space between the baffle and the discharge pipe D, can freeze solid without danger of breaking or cracking the co-acting parts of the drain.

the cover F of the sealing member E has been removed and preparatory to withdrawing the sealing member E from the receptacle C. I pre- 'fer, however, to mount a valve or closure G on Another desirable featureof the drain, :is; that the upper end portion of the discharge pipe D, and provide means for causing said valve to close automatically when the baiiie E is removed, and to open automatically when the bafile E is replaced in the receptacle C. As shown in Fig:- ures 1 and 2, a weighted valve or closure G, that ispivotally mounted on the upper end portion of the discharge pipe D, is provided with a lat-, erally-projecting arm 6. An actuating device 1, that is carried by the baffle E, is so arrangedthat when said bafile is moved downwardly into the receptacle 0,- the actuating device I will engage the arm 6 of the valve G,- and move said valve upwardly into its open position, shown in Figure; 2. 'When the baiile E is withdrawn from the receptacle C, the actuating device-1 will be dis-; engaged from the arm 6 of the valve-G, and said valve will then drop into its closed position, thus closing the outlet or discharge pipe D of the drain. All of the above described operations can be performed from the top side of thereof B when the roof is floating on the liquid in the tank. When my improved valve is intended to be used one. breather type roof, it is necessary to use a substantially inverted, cup-shaped sealing member or baflle, or, in other words, a seal-. ing member whose upper portion is gas-tight; In Figure 4 of the drawing I have illustrated a drain designed for use with a breather type roof.-

In general construction,it is similar to the drain shown in Figure 2, except that the removable sealing member or baflle E is provided witha gas-tight head orupper end F'. The-side wall portion of the receptacle C is attached tothe roof B, so that its upper end terminates above the top side of the roof, thus causing waterf to' 1. A siphon drain, comprising a receptacle dis posedso that drain water will enter the upper end of said receptacle, the side' wall portion of said receptacle sloping outwardly from its I lower towards, its upper end, a vertically-disposed"dutlet or discharge pipe for said receptacle having its upperhendterminating at a'point above the bottom-of saidreceptacle,.said receptacle being adapted to contain a liquid sealing medium when the drain is in use, and; a baflie of substantially; the same shape as z'the: sidewall portion iof.;the'

a relatively tall, narrow slot having a width ap-' proximately one-third the width of the annular space between the battle and the discharge pipe of the receptacle.

3. A drain of the kind described in claim 1,

in which the discharge pipe is provided with a valve, and means controlled by the bafile for opening and closing said valve.

4. A drain, comprising a receptacle disposed so that water can drain or flow into the upper end of said receptacle, an outlet or discharge pipe in the bottom of said receptacle, projecting upwardly' into same and terminating at a point above the bottom of said receptacle, said receptacle being adapted to contain a liquid sealing medium when the drain is in use, a bafile or sealing member removably mounted in said receptacle between said discharge pipe and the side wall of the receptacle and arranged with its lower end portion submerged in the liquid sealing medium and spaced away from the bottom of said receptacle, and a valve for closing said discharge pipe when the bafile is removed.

5. A drain of the kind described in claim 4, having provision for causing said valve to close automatically when the baflle is removed and for opening said valve automatically when-the baffle is replaced in said receptacle.

JOHN H. WIGGINS.

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