US2241843A - Means for storing volatile fluids - Google Patents

Description

May 13, 1941. E. BUDDRUS ETAL MEANS FOR STORING VOLATILE FLUIDS Filed April 29, 1938 INVENTOR. E. BU DD RUS G. W. M CULLOUGH 'ATTORE Patented May 13, 1941 MEANS FOR STORING VOLATILE FLUIDS Edward Buddrus and Gerald W. McCullough,

Bartlesville, kla., assignors to Phillips Petroleum Company, a corporation of Delaware Application April .29, 1938, Serial No. 205,092

. 2 Claims.

Apparently there are three main causes for 4 this evaporation of oil or gasoline in storage. One of these causes is wind-drift," or vapor circulation through openingsin the roof and eaves. A second cause for these losses occurs in the so-called breathing" of a tank after a wide variation in temperature has caused alternate expansions and contractions of the air and vapors above the fluid in the tank, with alternate outflow of vapor-saturated air and inflow of unsaturated air. The third cause relates especially to steel tanks, the walls become heated by the sun throughout the day, resulting in convection currents inthe fluid carrying this heat throughout the tank. In addition, these currents carry all parts of the fluid to the surface where the joint effect of the heat and circulation is evidenced by an accelerated evaporation rate and a selective evaporation of the more volatile constituents.

An important object of this invention is to provide a way of minimizing the evaporation of the light and valuable fractions which are lost in large quantities under the present methods of storage.

Another object of this invention is to provide a means for keeping the vapor space cooler during the day and to maintain the internal temperature of the contents of the tank at a relatively constant point.

A further object of this invention is to provide a commercially practical genus of heat reflecting and heat insulating for roof and side walls of such storage tanks.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawing, forming apart of this specification, and in which like numerals are employed to designate like parts throughout the same,

The illustrated apparatus is a side elevation 'cated with the numeral 6.

partly in section of a storage tank embodying this invention.

In the drawing, wherein for the purpose of illustraiton, is shown a preferred embodiment of this invention, the numeral l6 designates a gasoline storage tank of ordinary construction, except for the improvement hereinafter described, comprising a side wall 5 of sheet metal riveted or bolted in the approved manner to the roof covering 6 and the vertically extending flange IS. The side walls 5 of the tank are mounted on a concrete base I4 or other firm foundation. It is to be understood that any standard constructed storage tank is contemplated as being used in connection with this invention. For this reason the accompanying drawing does not show the customary posts supports for side wall and roof, beams, pillars, and vents used in tank construction, as they are not directly related to the later described improvements which constitute the invention.

Similarly the ordinary roof covering is indi- This may be any standard roof cover composed of weather proof, fire proof, and gas proof laminations sealed together.

Overlying the roof cover 6 is placed rows of flbre it produced from fused argillaceous limestone blown into fibres by steam. This flbre, commonly known as rock wool, is applied so as to blanket the entire upper surface of roof cover 6 as shown in the drawing. Due to'differences in operating conditions we have found that this rock wool should be applied so as to vary in thickness from one inch or less in some cases, to four inches or more in others. As shown, the rock wool blankets 8 are placed between the angle irons 9 and held in place by a wire netting, or in any other approved manner that will allow the outer surface of the rock wool to be exposed to the sun and air currents.

It is to be noted at this point that the above .8 is placed on top of the roof covering 6 as the preferred embodiment of this invention, but it is to be understood that the rock wool may be attached to the inner surface l8 of the roof covering 6 and still be within the scope of the appended claims.

Arranged above the rock wool blankets is a spray system I designed to discharge a spray of water over the outer surface of the rock wool. This spray system H) may take any form or arrangement desired. One method of connectin such a system is shown in the figure. A pump l2 draws water from the tank I3 and discharges it into the pipe H which carries the water to the spray system I 0. After the water is discharged from the sprays it soaks through the rock wool blankets 8 and collects in the trough formed by the roof covering 6 and the flanged member l5, and is discharged by gravity flow through pipe I! into tank l3.

From experiments we have found that tanks, containing gasoline or crude oil of high gasoline content, preferably of 25,000; 50,000; and 80,000 barrel capacity cone-breather or floating-roof types, are practically and economically insulated in regard to the side walls by covering the outer surface 1 with a thin adhesive coating of a preparation of White pigment. This phase of the invention is best exemplified by, and will be described as providing a means for reflecting radiant heat. A side wall with the outer exposed surface strongly reflective of radiant heat prevents the substantial transmission of such heat to the fluid in the interior of the tank.

The operation and efiect of the water soaked rock wool on the roof of the tank and white coated side walls is as follows:

Rock wool blankets 8 are applied directly on top of .the storage tank. They may be left dry, utilized solely as an insulating material, or it maybe installed in conjunction with a water spray system. In this case, the rock Wool is even more beneficial as it retains a portion of the moisture by virtue of its sponge effect and through the resulting evaporation creates and causes considerable cooling on the tank top.

This cooling of the tank top and the reflecting of the radiant heat waves on the side walls results in a reduction of the evaporation losses within the tank by minimizing the fluctuations of temperature and retarding volatilization of the liquid.

It is to be understood that the form of our invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

We claim:

1. In a tank for storing volatile hydrocarbons having a roof of weather-proof construction and side walls joined thereto, a permeable insulating material comprising rock wool upon the tank roof and substantially coextensive therewith, a spray system for spraying water on the insulating material to cool the top of the tank, means on the top of the tank to confine excess water which percolates through the insulating material on the top of the tank, and means to collect said excess water and transmit the same back to the spray system for repassage therethrough.

2. In a tank for storing volatile hydrocarbons having a roof of weather-proof construction and side walls joined thereto, a permeable insulating material comprising rock wool upon the tank roof and substantially coextensive therewith, an

adhesive coating of white pigment on the side walls, a spray system for spraying water on the insulating material to cool the top of the tank, a flange on top of the tank around the outer periphery thereof to confine excess Water which percolates through the insulating material on the top of the tank, and means to collect said excess water and transmit the same back to the spray system for repassage therethrough.

EDWARD BUDDRUS. GERALD W. McCULLOUGH.

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