US1796010A - Prevention of evaporation losses - Google Patents

Description

March l0, 1931. 1 F EAK|NS 1,796,010

PREVENTION OF EVAPORATION LOSSES Filed July 2. 1927 2 Sheets-Sheet 1 2 Sheets-Sheet 2 /l/l I6 x l l l I Il @672 0&72 fb/6m.) I

Filed July 2, 1927 J F EAKINS PREVENTION 0F EVAPORATION LOSSES Filth? l March l0, 1931.

Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE JOHN F. EAKINS, OF EVANSTON, ILLINOIS, ASSIGNOR TO STANDARD OIL COMPANY, 0F WHITING, INDIANA, A CORPORATION 0F INDIANA PREVENTION OF EVAPOR-ATION LOSSES Application led July 2, 1927. Serial No. 203,114.

This invention relates to the prevention of evaporation losses from volatile liquids, and particularly from hydrocarbon or mineral oils containing volatile fractions.

The invention will be readily understood from the following description, in which:

Figure 1 is a sectional view of a valve and associated operating mechanism, for controlling the admission of gases and vapors to a liquid storage system;

AFig. 2 is a sectional view on tlie line 22 of Fig. 1;

y Fig. 3 is a sectional view on the line 3 3 of Fig. 1; v

Fig. 4 is a sectional view of a valve assembly similar to that-shown in Fig. 1, associated with a -valve and operating mechanism for controlling the escape of gases and vapors from a storage system; and

Fig. 5 is an elevation ofv a general apparatus embodying the valve assembly shown in Fi .4.

lgteferring to the drawings, 10 is a chamber into which leads a conduit 11 from the vapor lspace of a liquid storage system. The chamber 19 is provided with a vertical. outlet 12 around which is constituted a sealing liquid channel 13 by exterior walls 14. An inverted' cup 15 is provided, said cup having a depending skirt 16 which is adapted to extend into the sealing liquid in the channel 13. The inverted cup is provided with means normally tending to maintain it in an elevated position. As shown in the drawings, this means may take the formof an air chamber or float 17 preferably located around the lower edge of the skirt 16 so that the buoyancy thereof will exert a constant upward force during all or substantially all positions of the inverted cup. The walls 14 preferably terminate in a flange 18 and a cover 19 is provided .having a flange 20 adapted to co-operate with the flange 18. The cover 19 is perforated, .as shown at 21, so that the upper side of the inverted cup 15 is 'subjected to atmospheric pressure. The cover 19 is .constructed so as to permit sullicient movement o f the inverted cup 15 for a purpose which will hereinafter appear. l Within the chamber-10 is provided a horizontal open mouth 22 which leads into a conduit 23 which is adapted to be connected to a pressure line 24 whereby gases and vapors may be supplied into said chamber. The mouth 22 is surrounded by a channel 25 adapted to receive sealing liquid, and is provided with a cylindrical valve 26 pivoted about its axis, at 27, and having depending skirts adapted to be immersed in the liquid in the channel 25 for the purpose of forming a liquid seal when the valve is in its closed position, as shown in Fig. 1. The valve 26 is weighted, as shown at 28, so as to tend to maintain said valve open.

A cord 29 extends from the underside of the inverted cup 15 and is attached to the valve 26 near the weight 28, or other suitable point. A grooved wheel 30', suitably mounted in the chamber above the valve 26, is provided fpr the purpose of guiding the cord 29.

The float 17 or other means which may be employed for imparting an upward force to the inverted cup 15, is designed or regulated so as to permit a certain predetermined degree of subatmospherc pressure in the chamber 10 before the valve 26 opens. For example, in dealing with gasoline tanks of great size, it is necessary to avoid a pressure difference of more than, say, one-tenth of aninch of water between one side of the tank roof and the other. It isl obvious that by adjusting the size of the float 17 or the weight 28, in conjunction with the mass of the cup 15, it is possible to insure the opening of the valve 26 when the excess pressure of the atmosphere attains that amount.

The valve structure hereinbefore described may suitably be combined with the valve structure described and claimed in the application of Harold V. Atwell, Serial No. 180,321, filed April 1, 1927. This combination is lillustrated* in Fig. 4, in which the right-hand side shows the yvalve and associated parts hereinbefore described, the same reference numerals being applied to designate the same parts. On the left-hand side is shown the valve described and claimed 1n the application above referred to. This structure is located in the same chamber 1() which is provided with a vertical outlet 31 ber 10. A gas-holder 42 is provided for the I corresponding to the vertical outlet 12. The outlet 31 is surrounded by a sealing liquid channel 32 which may communicate with the channel 13. The cover 19 may be common to both valves. The vertical outlet 31 is closed by an inverted cup 33, similar to the inverted cup 15, but unprovided with a float or other means normally tending to force same into an elevated position.

A horizontal mouth 34 opens into the chamber 10, said mouth leading into a conduit 35 which is adapted to be connected to a vacuum line 36. The horizontal mouth 34 is provided with a cylindrical pivoted valve 37 adapted to co-operate with sealing liquid in a surrounding channel 38. The valve 37 is similar to the valve 26, but is provided with a Weight 39 adapted to tend to maintain it in the closed position. The underside of the inverted cup 33 is connected to the valve 37 by a oord 39 which passes over a grooved wheel 40, said cord being attached to the valve 37 near the Weight 39.

The weight and area of the cup 33 and the weight 39 are so designed or adjusted that the valve 37 is opened when the pressure in the chamber 10 exceeds atmospheric by the excess pressure permissible in the storage tanks, for example, one-tenth ofan inch of water. l

The installation of the combined valve assemblage just described in a typical st orage system is shown in Fig. 5 in which 41 are petroleum storage tanks, the vapor spaces of which are connected by pipe 11 to the chamstorage of gases and vapors. The pressure line 24 communicates with the gas-holder and is connected to the conduit 23 which is controlled by the valve 26. lThe vacuum conduit 36 is connected to the suction side of a pump 43, which may be operated continuously or l intermittently to maintain a low pressure in line 36 and to pump gasesand vapors therelfrom by line 44 into gas-holderl 42. It must be understood that the gas-holder 42 is merely shown by way of example, since the lines -44 and 24 may be connected to any other suitable apparatus for the reception and supply, respectively, of gases and vapors.

The operation of the valve assembly shown in Figs. 1 to 3,.and on the right-hand side of the chamberl() in Figs. 4 and 5, is as follows:

'Assuming atmospheric or somewhat higher pressure in the vapor spaces of the tanks 41. then the inverted cup 15 under the buoyancy of oat 17 is in its elevated position, as shown in Figs. 1 and 2.l If the pressure in the vapor space in the tanks 41 decreases to the predetermined minimum below atmospheric, for example one inch of water below said pressure, the excess pressure of atmosphere acting z on the upper side of the inverted cup 15, to

gether with action of the weight 28, is sufficient to overcome the buoyancy of the float y openin 17 so that the valve 26 opens and the parts move into the position shown on the righthand side of Fig. 4. When this happens gases and vapors pass from the pressure line 24 into the chamber 10 and from there they proceed by line 11 into tanks 41 thereby preventing excess vacuum therein. When the pressure' in said tanks becomes higher than the safe minimum, the valve 26 is. closed again.

The valve 37 and associated parts in the left-hand side of the chamber 10, as shown in Figs. 4 and 5, operate as described in the aforesaid application. That is, when the pressure in the vapor spaces of tanks 41 ex ceeds atmospheric by a predetermined amount,`for example, by one inch of Water, said excess of pressure is exerted upon the underside of the cup 33, moving it upwards and opening the valve 37. Thereupon gases and vapors pass into the vacuum line 36 and are withdrawn therefrom by pump 43 and fed through line 44 into the gas-holder 42 until the pressure in the tanks 41 `is reduced below the safe predetermined maximum pressure, whereupon the inverted cup 33 descends and the valve 36 closes again.

It is to be noted particularly thel valves 26 and 37 being cylindrical in form and pivoted axially, are unaffected by the difference of pressure on one side or the other, andtheir of and closing is effected primarily by the difference of pressure in the ytanks 41 and the atmospheric pressure exerted upon the inverted cups 15 and 33.

Although the present invention has been described in connection with the details of specific embodiments thereof, it is not intended that suchdetails shall be regarded as limitations upon the scope of the invention, except in so far as included in the accompanying claims.

I claim:

1. A valvestructure comprising a chamber, a conduit leading into said chamber, an outlet from said chamber, vertical walls aroundy said outlet forming a channel for sealing liquid, an inverted cup over said outlet having a skirt depending into said channel, means outlet from said chamber, vertical walls around said outlet forming a channel for sealing liquid, an inverted cup over said outlet having a skirt depending into said channel, a oat adapted to maintain said cup in an elevated position except when subjected to a aconduit leading into said chamber, an outv let from said chamber, vertical walls around said outlet forming a channel .for sealing liquid, an invert-ed cup over said outlet having. a skirt depending into said channel, means tending to maintain said cup in an elevated position, conduit means extending partially into said chamber so .as to constitute therearound a channel for sealing liquid, a pivoted valve over said conduit with sides extending into said channel, means connecting said inverted cup to the pivoted -valve so as to effect rotation and opening of same when the inverted cup is moved inwardly by excess of atmospheric pressure over the pressure in the chamber.

4. A valve structure comprising a chamber,

' a conduit leading into said chamber, an outlet from said chamber, vertical walls around said outlet forming a channel for sealing liquid, an inverted cup over said outlet having a ,skirt depending into `said channel, a float tendingI to maintain said cup in an elevated position, conduit means extending partially into said chamber so as to constitute therearound a channel for sealing liquid, a pivoted valve over said conduit with sides extending into said channel, means connecting said inverted cup to the pivoted valve so as to effect rotation and opening of same'when the j inverted cup'is movedinwardly by excess of channel, means tending to maintain said cup man elevated position, a conduit leading intov atmospheric pressure over the pressure in the chamber.

5. A valve structure comprising a chamber, a conduit leading into the side thereof, an outlet extending upwardly from the top of said chamber, vertical walls around said outlet and in sfpaced relation theretov forming a channel or sealing liquid, an inverted cup having a depending skirt extending into said the bottom of said chamber and extending f ther-cinto so as to constitute a channel for sealing liquid therearound, a pivoted valve member having sides which extend into said Y (sov ber, a conduit leading into the` side thereof,

an outlet extending upwardly from the top of said chamber, vertical walls around said outlet and in spaced relation thereto forming a channel for sealing liquid, an inverted cnp having a depending skirt extending into said channel, means tending to maintain said cup in an elevated position, a conduit leading into the bottom of said chamber and extending thereinto so as to constitute a channel for sealing liquid therearound', a pivoted valve member havin sides which extend into said channel, a Weight on said valve normally tending to open same, and flexible means connecting said inverted cup to said valve member so that downward movement of the inverted cup permits rotation and opening of said valve and upward movement of Said cup effects the closing of said valve.

7. A valve assembly comprising a liquid vsealed inverted cup subjected to atmospheric pressure on one side and a variable vapor pressure on the other, a pivoted cylindrical liquid scaled valve adapted to close a Vapor conduit, means normally tending to open said valve, and means connecting said valve and cup to cause same to operate in unison.

8. A valve assembly comprising a liquid sealed inverted cup subjected to atmospheric pressure on one side and a variable vapor Vpressure on the other, a pivoted cylindrical valve adapted to close a vapor conduit, a weight on said valve normally tending to open same, and iiexible means connecting said valve and cup to cause same to operate in unison. A

9. A valve assembly comprising a pair of liquid sealed inverted cups subjected vto atmospheric pressure on one side and a variable vapor pressure on the other, a pair of pivoted cylindrical valves ada ted to close a pair of vapor conduits, flexible means connecting each cup to a valve so as to cause each valve to operatein unison with a cup, means for exerting -a force on one ofsaid cups in the same direction as the eect of the vapor pressure, means on the valve associated with said cup tending to open same, and means on the other valve tending to close same.

10. A valve assembly comprising a pair of controlling members subjected on one side to atmospheric pressure and on the other side to a variable vapor pressure, means adapted to exert force on one of said members in the same direction as the eliect of said vapor pressure, a pair' of valves controllin vapor conduits and connected to said mem ers so that one valve opens when the atmospheric pressure exceeds said vapor pressure by a predetermined amount and the other opens when said vapor pressure exceeds atmospheric pressure by a predetermined amount.

11. A valve structure comprisin a chamber, a conduit leading into said c amber, a pair of outlets from said chamber, vertical Walls around said outlets forming channels for sealing liquid, a pair of inverted cups over said outlets having skirts depending into said channels, a float tending to maintain one of said cups in an elevated position,

a pair of conduits leadin from said chamber, valves controlling said conduits, means connecting each inverted cup to a valve to. effect operation thereof from the movement 0f the inverted cup.

12. A valve structure comprising a chamber, a conduit leading into said chamber,` a pair of outlets from said chamber, vertical Walls around said outlets forming channels for sealing liquid, a pair of inverted cups over said outlets having skirts dependinginto said channels, means tending to maintain one of said cups in anl elevated position, a pair of conduits extending partially into said chamber so as to constitute channels for sealing liquid, pivoted valves over said conduits -With sides extending into said channels, means connecting said inverted cups to the pivoted valves so as to eiiectrotation and opening of one Valve when the corresponding inverted cup is moved outwardly by excessof pressure in the chamber over atmospheric pressure and the rotation and opening of the other valve when the corresponding inverted cup is moved inwardly by excess of atmospheric pressure over the pressure in the chamber.

13. A valve structure comprising a chamber, a conduit leading into said chamber, an outlet from said chamber, vertical Walls around said outlet forming a channel for sealing liquid, an inverted cup over -said outlet having a skirt depending into said channel, means adapted to maintain said cup in an elevated position, except when subjected to a predetermined excess of pressure on its exterior, a second outlet from said chamber, avalve in said chamber controlling said second outlet, and means connecting -saidinverted cup to said valve to effect operation thereof from the movement of the inverted cup.

JOHN F. EAKINS.`

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