US2536077A

US2536077A - Vent for floating roof tanks

Info

Publication number: US2536077A
Authority: US
Inventors: Clifford M Orr; Fred L Goldsby
Original assignee: Chicago Bridge and Iron Co
Current assignee: Chicago Bridge and Iron Co
Priority date: 1946-10-17
Filing date: 1946-10-17
Publication date: 1951-01-02
Anticipated expiration: 1968-01-02

Description

Jan; 2, 1951 c. M. ORR ETAL VENT FOR FLOATING ROOF TANKS 2 Shee ts-Sheet 1 Filed Oct. 17, 1946 lrznaaiiiiiiiii Jan. 2, 1951 c. M. ORR EI'AL 2,536,077

VENT FOR FLOATING ROOF TANKS Filed Oct. 17, 1946 '2 Sheets-Sheet 2 Patented Jan. 2, 1951 a aaa be m r "111., a'ssigmsrs" to Chicago panwattriibraudn of rumors "Application Gbtbber 17, 1946,: Serial-N0. 702%,732 wane. (x 220 443 invention relates to a vent, andlmor e particularly to a ventjora floating roof tank.

Volatile liquids are often stored in tanks having a roof floating upon the surface of the liquid stored therein, adapted to rise and fall with the liquid level within the-tank; Such floating roofs are generally provided with some sort of supporting means to maintain the roof a .predetermined distance abovethe bottom of the tank even though all or substantiallyall of the liquid is drained from the tank. l V

Difliculty has been ;experienced when reintroducing liquid to a floating-roof tankfrom which the liquidhas been previously withdrawn,

in that no means is provided for the air within the tank between the bottomandthe roof to escape as liquid is being introduced. This has resulted in a large air bubble formingunder the roof.

Difficulty has also been experienced in draining such a tank completely; as means must be provided for allowing air to enter the space between the roof and the tank after the roofhas reached its lowest position in orderto permit-the liquid to escape. w

We have 1 invented, and are herein disclosing and claiming, a vent for afloating roof tank which is automatically openedwhenthe roof falls to a predetermined height above the' bottom of the tank thereby permitting air to enter the space below the roof as further liquid is drained, and permitting 'air-to"scape from said space when liquid is introduced into the tank.

The invention will be des cribed as embodied-in the illustration shown in the "accompanying drawings in which Fig. 1 is a top elevation of a portion of a liquid storage tank and a floating roof; Fig. 2 is a vertical section along fines e-=4 of Fi 1; .7 fFig. 3 is a vertical section along lines 2=+2aof Fig. 1 with a roof at a higher position above the bottom of the tank;

Fig. 4 is a vertical section through a portion of the floating roof showing our vent;

Fig. 5 is a horizontal section along lines 5-5 of Fig. 4;

Fig. 6 is a plan view along lines 6-6 of Fig. 4; and,

Fig. 7 is a top elevation along lines 1-1 of Fig. 4.

Referring to the drawings, a portion of a cylindrical tank 10 is shown, having side walls II and a bottom I2. A floating roof [3 of usual construction is adapted to float upon the surface of the liquid contained within the tank. It is the upper portion of the cylinder is a scaling iii.)

customary in such installations to provide sealing means between the edge of the floatingroof and-thetank to prevent loss of vapor from that :s-pace; *howeven such sealing means form no part of this invention and hence are not shown in the drawings.

A plurality of supporting posts it are pr'ovidedabo'ut thereof being received into -the pipe-like members [5 extending throufghthe roof andadapted to restupon the bottom of the tank or uponpedestals I6 attached to the bottom. It is customary to connectthe support Hi to the pipe lfiby'adjustable means; such as'a bolt H,

in order that the'height above the bottom may be varied as required. For example, the bolt'might be positioned as shown inFig. 2 oras shown in Fig. 3; Theipedestals l6 are not necessary and thesupports may rest directly upon the bottom of the tank.

The vent comprises a cylinder 18 formed in the roof f3 and extending th'e'rethrough. Sealing member, being in the embodiment shown, in the form of aninverted cup 19. We prefer to construct the sea ing member of metal and attach thereto, such as by means of rivets 2E!,a resilient sealing member 2|. We1dedto thecu'p t9 is a pipe-like member '22 extending downwardly *throu'ghthecylinde'r I8; An actuating element 23is connectedto the member 2| by' meansbf a bblt 24; Inthe einbodiment shown, the actuatin'g element is in the'form 'o'f'a hollow rodhaving a plurality of hoZes 25 formed therein, which hol'es match a-hole-26 formed in the pipe -like ii'iember' 22. The b'olt z l issecured in position bya cdtter'pi'n 2'! or other means, and the bolt may 'be withdrawn and reinserted through the hO'IeS 26', the mmbr 22- and-another 0f the holes "25 in the member 23 tovary the relative position of the hollow rod 23. This latteradjustment is further aided by a bolt 29 threadin'g' i'rlto a'nut 30 attached to the bottom of the member 23. Positioned on the bottom I2 of the tank is a pedestal 3! comprising a flat, circular plate 32 attached to angle irons 33 which are in turn attached to the bottom of the tank at 34 as shown. As stated before, the pedestals may be dispensed with, if desired, and the term bottom used throughout this application should be taken to mean either the bottom of the tank or the top of a pedestal, or the like, attached to the bottom, as the case may be.

As can be seen from an examination of Fig. 4, a further lowering of the roof l3 would cause the end 28 of the member 23 to strike the bottom of the tank (the bottom in this case being the top of the pedestal 3|). The member 23, being connected by bolt 24 to the pipe 22, prevents further vertical movement in a downward direction of thecup l9, and further lowering of the roof thereupon lowers the cylinder l8 below the cup, opening the space under the roof to the atmosphere. The roof may continue to drop until the supports 14 contact the bottom halting its movement. The liquid within the tank maybe completely drained without danger of a vacuum forming beneath the roof as the cylinder l8 remains open to the atmosphere.

As liquid is reintroduced to the tank and rises therewithin, air may escape through the cylinder l8 and no pressure is built up beneath the roof. As the liquid reaches the bottom of the roof and continues to rise, it eventually will float the roof oil the supports Hi. Further upward movement of the roof will bring the upper portion of the cylinder l8 in contact with the seal 2!, closing the vent and lifting the member 23 off the bottom.

In order to center the pipe 22 within the cylinder, tapered

vanes

35, 36 and 3'! are provided. These vanes are attached to the pipe 22 and are adapted to slidably contact the interior of the cylinder H3. The tapered portion 36 of the vanes is adapted to guide the pipe to the center of the cylinder as the roof rises. A manually operable vent 40 is also provided, comprising an opening 4| in the side of the cylinder iii to which is attached a pipe 42 capped at the opposite end by a metal cap 43, and a resilient seal 44. Wing nuts 45 and 45a attached to bolts on the pipe t2 and fitting into slots 46 of the cap 43 permit the same to be opened manually.

Our vent serves not only to open communication between the atmosphere and the space beneath the roof while the roof is below a predetermined height within the tank, but also serves as a pressure vent. It can be seen that excessive pressures within the tank would lift the cup and open the vent. The amount of pressure necessary to open the vent will vary, of course, with the weight of the

members

22 and 23 and the cup l9. Additional weights may be added to the structure to raise the pressure necessary to open the vent without interfering with the function thereof when the rOOf is below the predetermined height. The supporting posts and the member 23 are provided with a ring 46 to facilitate the placement of the bolts l1 and 24 in the variou holes, as desired.

While we have shown and described our invention in its preferred embodiment, it is to be understood that it is capable of many modifications.

Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

We claim:

1. In a floating roof tank having a roof adapted to float on liquid within the tank, a vent comprising: a substantially vertical cylinder formed in said roof and extending therethrough, an inverted cup sealing the upper end of said cylinder, a pipe connected to said cup and extending into said cylinder, an elongated element connected to said pipe and extending beneath the roof, said element being in contact with the bottom of the tank in all positions of the roof below a predetermined height to prevent vertical movement of said cup with vertical movement of the roof below said predetermined height whereby said cylinder is opened to the atmosphere at all pressures in the space beneath the roof in all positions of the roof below said predetermined height.

2. The vent of claim 1 including centering means attached to said pipe to guide said pipe to the center of said cylinder.

3. The vent of claim 1 including tapering centering means attached to said pipe adapted to guide said pipe to the center of said cylinder as the roof rises from below said predetermined height.

4. The vent of claim 1 in which said element is connectable to said pipe at a plurality of positions to vary said predetermined height.

5. In a floating roof tank having a roof adapted to float on liquid within the tank, a vent comprising: a substantially vertical cylinder formed in said roof and extending therethrough, an inverted cup sealing the upper end of said cylinder, a pipe connected to said cup extending into said cylinder, an element connected to said pipe adapted to be in contact with the bottom of the tank in all positions of the roof below a predetermined height to prevent vertical movement of said cup with vertical movement of the roof below said predetermined height whereby said cylinder is opened to the atmosphere at all pressures in the space beneath the roof in all positions of the roof below said predetermined height, said element being connectable to said pipe at a plurality of said positions to vary said predetermined height, and said element being provided with adjustable contacting means on its bottom end to precisely adjust said predetermined height.

CLIFFORD M. ORR. FRED L. GOLDSBY.

Name Date Laux May 2, 1905 Lange Dec. 28, 1926 Wiggins Oct. 1'7, 1933 Wiggins Aug. 11, 1936 Num er