US 1690072 A
Description (OCR text may contain errors)
Oct. 30, 1928.
LIQUID LEVEL 1,690,072 C. R. JOHNSON RECEPTACLE FOR VOLATILE LIQUIDS l3, 1924 2 Sheets-Sheet l Filed Nov.
LLIQUID LEVEL FIG. 2 m CLEOH JOHNSON .hwnli Oct. 30, 1928. 1,690,072
c. R. JOHNSON RECEPTACLE FOR VOLATILE LIQUIDS Filed Nov. 13, 1924 2 Sheets-Sheet 2 WlRE. 502mm EUPPOTZ'HNQ CHAMBER CLEOH Jm-mson H mwm Wk/ax CTHcmul Patented Oct. 30, 1928.
UNITED STATES PATENT OFFICE.
CLEON a aonnson, or nous'ron, TEXAS, AssIGNoR' 'ro STANDARD on. DEVELOPMENT COMPANY, A CORPORATION or DELAWARE.
BE CE PTACLE FOR VOLATILE LIQUIDS.
Application filed November 18, 1924. Serial No. 749,721.
. tainers there is considerable loss by volatilization. Also, upon decrease of temperature a partial vacuum may-form in the container and air is drawn in." This is often highly undesirable on account of oxidation of the material, formation of explosive mixtures, o
According to the present invention these difliculties are avoided and positive advantages are obtained by providing an inflatable chamber within the container. The chamber is adapted to receive air which may tend to be drawn into the container because of a subatmos heric pressure therein. It is deflated with t 1e expulsion of the air when the temperature rises and there is a resultant increase of vapor pressure and expansion of vapors in the container to produce a superatmospheric ressure.
The invention will be more fully described in connection with the accompanying drawin in which i 1 is a vertical section through a tank provided with an inflatable chamber;
Fig. 2 is a similar view, showing the chamber inflated;
Figs. 3 and 5 are a top plan view of the tank, the cover being removed; and
F i 4 is a vertical section throu h a modified form of tank and inflatable c amber.
Referring to Figs. 1 to 3, reference numeral 1 denotes a tank such as is commonly used for the storage of gasoline. This has been selected for illustration because the invention is articularly applicable in this connection. here is no limitation to this use, as the means described is advantageous in the storage and shipment of volatile liquids generally. The tank is provided with a pressure-vacuum safety valve 2 and vent plpe 3. The ressure-vacuum valve will be set to relieve a normal pressures, such as are encountered particularl in 'ng or emptying the tank. A conica screen adapted to stop the passage of flame, may be installed over the valve. The screen is protected by a sheet metal cover S.
The inflatable chamber 4 comprises a bag substantially impermeable by air and by the vapor of the liquid. The bag may be made from any suitable impermeable material having sufficient strength and flexibility, for example cloth impregnated with a mixture of glue and glycerine. If desirable, wires or other supports 5 may beprovided to keep the bag from contact with the liquid in the tank. A screen S may be installed in the vent ipe 3, in case there should beleakage of in ammable vapor through the bag. We may use a chamber having metallic walls 'ointed for expansion, or similar devices,
at in general-balloonlike receivers are more suitable.
The inflatable device is placed within the tank and connected to the vent pipe. The device is preferably of such size that when fully inflated it occupies about 20-40% of the volume of the vapor space in the tank. It may of course be larger, if desired, but in e(general it should not be smaller when us in connection with liquids as volatile as gasoline. Where very high temperatures are likel to be encountered the inflatable chamber s ould be correspondingly capacious.
It is desirable to attach the inflatable chamber or bag in deflated condition when the temperature is high; or inflated, at a time of low temperature. If it is attached when the temperature is high the ba will assume the position shown in Fig. 1. pon fall of temperature, air will be drawn 1n and will distend the bag to the position shown in Fig. 2. When the temperature rises again the pressure of the vapors evolved in the tank will compress the bag and force the air from it. The tank is thus permitted to breathe without any interchange between its contents and the atmosphere.
In the form of the invention shown in Fi 4, the principle is the same, but an expansib e device 6 having a central opening is used. This is so arranged that it avoids the supporting columns 7 which sustain the roof of the tank 8. It is illustrated in inflated condition and as enerally annular in contour.
The inflatab e member may be immersed in the liquid at least in part, provided the hydrostatic pressure upon it is not suflicient to interfere with its proper operation and that the material of the inflatable member is not injured by contact with the liquid. Unless the inflatable member is strong enough to sustain the maximum pressure that may be exerted upon it, the provision or a safety valve 9 on the vent pipe 3 is desirable. The valve may be adjusted to close at a predetermined pressure, thus shutting oii further entry of air into'the member. A manually operated valve may be used, if desired.
By means of the present invention valuable vapors are substantially completely retained at all times within the container and air is prevented from entering it. In addition to preventing the wastage of gasoline or the like, the present invention has'a further important advantage in avoiding the fire risk incident to the outward breathing of inflammable vapors.
Various modifications of the illustrative constructions described may be made within the scope of the appended claims.
1. A storage tank having a roof supported by a plurality of columns, a. vent through said roof, an ex )ansible-chamber encircling a portion of sai columns, and a connection between the chamber and the vent.
2. Storage 0. paratus for volatile liquids, comprising a c osed container having a vent,
an inflatable member within said container and an opening to the exterior thereof through the vent, said member being actuated by variation of pressure in the container, and a safety valve on the vent uctuable to pre- Egnt excessive pressure on the inflatable memr. 3. Storage apparatus for volatile liquids, comprising a closed container having a vent, an inflatable member within said container and opening to the exterior thereof through the vent, a screen below the member and adapted to support the same out of contact with the liquid, said member being actuated by variation of pressure in the container, and a fire-stopping screen arranged in the vent.
4. Storage apparatus for volatile liquids comprising a container having a vent, an inflatable member within the container and opening to the exterior thereof through the vent, and a screen adapted to support the member permanently out of contact with the liquid, said member being actuated by variations of pressure in the container and when fully expanded occupying 20 to 40% of the vapor space normally left above the li uid.
CLEON R. JOHN ON.