US2348546A - Fuel gas dispensing apparatus and method - Google Patents

Description

May 9, 1944. A. J. KERCHER FUEL GAS DISPENSING APPARATUS AND METHOD Fi led Jan. 13, 1942 2 Sheets-Sheet 1 F'II5 J .JNVENTOR flrf/vur J Kara/7e,-

BY W I ATTORNEY 2 Sheets-Sheet 2 fir/huf J ,Vercher BY @1 9% FIIE E MN m 21 J 4A &\A x A, w

A. J. KERCHER Filed Jan 15,1942

, 6 I I ll May 9, 1944.

FUEL GAS DISPENSING APPARATUS AND METHOD ATTORNEY Patented May 9, 1944 UNITED STATES PATENT OFFICE FUEL GAS DISPENSING APPARATUS AND THOD Arthur J. Kercher, Berkeley, Calif.

Application January 13, 1942, Serial No. 426,637

(Cl. 62l) 6 Claims.

This invention relates generally to apparatus for dispensing fuel gas such as butane from tanks in which the gas is stored in liquefied condition.

In dispensing fuel gas like butane, it has been common practice to store the liquefied gas in suitable containers with the upper part of the tank connected directly to a service supply pipe. Such an arrangement gives reasonably satisfactory results where the atmospheric temperature is relatively mild, or as long as suflicient heat can be absorbed by the tank to vaporize the liquefied fuel at a rate which will maintain the gas pressure desired. Where the tank is subjected to relatively low atmospheric temperatures, such a simple arrangement is unsatisfactory, and may be entirely inoperative. Under such conditions an insuflicient vapor pressure can be maintained in the tank to properly supply gas to the service line, particularly where the demand is relatively heavy. Direct heating of the tank under such Iconditions is not a satisfactory expedient and may involve fire hazards.

It is an object of the present invention to provide special apparatus for dispensing fuel, gas like butane, which will serve to sustain the presnure of the gas in the service line irrespective of atmospheric temperature.

Another object of the invention is to provide a novel type of vaporizer equipment for use with butane storage tanks, which equipment is operated automatically in accordance with the temperature of the tank.

Referring to the drawings:

Figure l is a side elevational view showing apparatus incorporating the present invention;

Figure 2 is an enlarged cross sectional view taken along the line 22 of Figure 1;

Figure 3 is a side elevational view in cross section, showing the construction of the vaporizer; and

Figure 4 is a sectional detail of valve operating rod.

In Figure 1 of the drawings there is shown a conventional type of storage tank M, such as is commonly employed for the storage of liquid butane. The upper portion of this tank is connected by the service pipe II to a point of gas demand, through the pressure reducing service regulator l2. The maintenance of a proper presv sure at the point of demand depends upon the 13 includes electrical heating elements.

ment is seriously impaired, or it may become entirely inoperative.

In conjunction with the conventional parts just described, I employ an electrical vaporizer l3 which can be installed at any convenient location, which in most instances will be near the storage tank It). Liquid from the tank In is introduced into the vaporizer l3 by the positive pump II which can be of the centrifugal type. The inlet side of this pump is connected to the lower side of the storage tank by pipe l5, and the discharge side is connected by pipe IE to the vaporizer l3. The vapor generated in vaporizer l3 passes by pipe ll-to the sevice pipe I I. In order to prevent back flow of vapor to the tank II], a small check valve I8 is inserted in the service pipe.

As will be presently explained. the vaporizer Also the pump I4 is preferably operated by means of an electric motor. An electrical circuit includes both themotor for pump l4 and the electrical heating elements, and this circuit includes the conductors 2i and 22 which lead to the thermostatic switch 23. Switch 23 can be of the double pole type, and connects to the current supply lines L1 and L2. The thermostatic control means of switch 23 has been shown in the form of an elongated element 24 which extends into the upper part of the tank In. Therefore, the thermostatic switch 23 controls supply of current to both the electric motor of the pump and the heating element of the vaporizer [3, in accordance with the temperature of the storage tank.

' While it is desirable that switch 23 be adjustable with respect to the temperature level of operation, in general it is set to close its contacts and thus supply current when the temperature of the tank falls to a relatively low value such as of the order of 32 F The manual switch 25 for the current supply lines can be operated at the point of gas demand.

A suitable construction for the vaporizer is shown in Figures 2 and 3. A feature of this device is the inclusion of a valve which controls communication between the vaporizing chamber and the discharge pipe Hi from the pump Id. The vaporizer as illustrated comprises a metal casing 26 which forms a closed vaporizing chamber 21. The lower end of this casing is attached to the hollow body 28, which in turn is closed by the bottom closure plate 29. Also at the lower end of casing 26 there is a header plate 3|, which serves to carry the tubular electrical heating element 32. These elements may vary in construc- 31, and are then connected to the source of current supply, through the contacts of a ther-v mostatic switch 38. Plate 31 is also sealed with respect to ring 33. Thermostatic switch 38 is for the purpose of preventing overheating oi the elements 32, and also serves to maintain the temperature of these elements relatively constant during operation, and irrespective of the amount of liquid being vaporized. This thermostatic switch may be similar to that disclosed and claimed in my copending application Serial No. 348,110.

The thermal responsive element for operating the switch may include the metal casings 32a of one or more of the heating elements 32, and which are connected at their upper ends through thrust member 39 to the rod 4|. This rod extends downwardly to the operating'parts of the thermostatic switch 36. The metal casings of the electrical heating elements are made of metal such as a copper alloy which expands when heated. Rod 4| should be made of a metal having no, or very little, thermal coefficient of expansion, as for example invar.

The pipe I6 which leads from the discharge side of pump [4 is connected to the fitting 42 at the'top of the casing 26. This fitting in turn is coupled to the fitting 43, which is attached to the top wall 44 of the casing 26. Within the fitting 43 there is a valve ball which is normally urged downwardly upon a seat 41 by the compression spring 48. Normally this valve means prevents flow of liquid from the pump l4 unless the ball 46 is moved to open position with respect to its seat.

Within the chamber 21 and below the fitting 43 there is an extension 49 of the top wall 44 whichforms a fluid chamber A tube 52 has its upper end connected to chamber 5| and has its lower open end terminating at .a point intermediate the ends of the vaporizing chamber. Extending upwardly through the extension 49 there is a valve operating rod 63, the upper end of which is adapted to engage the ball 46.

Preferably this rod includes a fusible link 64, as

shown in detail in Figure 4, in order to preclude operation in the event of fire. Briefly, this link is in the form of a socket 56 carried by the lower part of the valve rod and into which the upper part of the rod extends. The inner walls of the socket and the adjacent part of the valve rod are grooved to receive a ring 61 of readily fusible material, such as lead solder. When this solder fuses, the upper part of the rod may enter the socket a, farther amount to prevent automatic opening by the means to be presently described.

The rod 63 is operated automatically to open the valve ball 46 when the temperature of the heating elements 32 is sufficiently high to properly vaporize the liquid. Thermostatic operating means for this purpose can consist of a bimetal strip 6|, one end or which engages beneath the lower end of rod 63. The other end of this strip is retained against upward movement by attachment to the rod 62. The lower end of this rod is anchored to the plate 3|. Preferably this rod is of a material having no, or very little, thermal coefficient of expansion, such as invar. Thethrust member 39, which makes connection with rod 4|,'engages beneath an inter mediate portion of the strip 6|. Also the strip is held down upon thrust member 39 by a pin 63 in the upper end of rod 4|, which engages the leaf spring 64.

When the casings 32a of the heating elements expand, the free end of the bi-metal strip 6| is forced upwardly, and in addition heat directly transferred to this strip tends to cause the strip to curl upwardly, because 01 its bi-metal construction. About the time the heating elements reach their normal operating temperature, the upward movement of the bi-metal strip 6| has opened the ball valve 46 to permit infiow of liquid.

The pipe ll for outflow of vapor from chamber 21 connects with the upper end of the chamber through the top wall 44, as shown in Figure 3. An additional pipe 66 can connect to the chamber 21, as illustrated, and can lead to the maxpressure safety blow-oi! valve 61. 26 and body 26 are enclosed within an outer housing 69, which is packed with suitable heat insulatin material I I.

Operation of the apparatus described above can be outlined as follows: Normally, when sufiicient heat can be directly absorbed from the surrounding atmosphere to properly vaporize the liquid in tank I, current supplied to the electric motor of the pump and to the vaporizer is interrupted by the contacts of switch23. When the tank cannot absorb sufiicient heat to properly vapon'ze the liquid, as for example due to a relatively low atmospheric temperature which may be augmented by relatively heavy demand, the drop in temperature of the tank causes the closing of switch 23 which immediately starts the pump H in operation. and supplies current to the heating elements of vaporizer l3. Since the valve ball 46 is closed upon its seat, such initial operation does not cause discharge of the li uid into the vaporizer. As the temperature 0 the heating elements rises to substantially normal operating value, upward movement of the bimetal strip 6| opens the valve 46 to permit the liquid to enter and to be vaporized. The gas passes out through pipe I! to maintain a proper pressure upon the regulator l2. Check valve l6 automatically closes to prevent back fiow of vapor to the tank Ill. Thermostat 36 serves to maintain the temperature of the heating elements at a relatively con? stant value, and this temperature is adjusted to maintain the desired pressure upon the service regulator. The vaporizer will continue to operate automatically until the tank It, by absorption of heat from the surrounding atmospherefhas attained a temperature such as causes contact switch 23 to open. Within a short interval after discontinuing supply of current to the heating elements, the temperature of the vaporizing chamber 21 will drop down sufliciently to close the valve 46, thus placing the equipment in condition for further operation as described above. During intervais when the vaporizer is in. operation there is no danger of supplying more liquid to the vaporizer than is required, because the centrifugal pump i4 is selected and operated so that its maximum discharge pressure is not greater than the maximum pressure required upon the inlet side of the regulator l2. Therefore, in the event f the demand ceases for an interval while current The .casing assume 3 is supplied to lines 2| and 22, a pressure will quickly build up within the vaporizer to automatically prevent further inflow oi! liquid from the pump through pipe l6.

Iclaim:

1. In apparatus for dispensing Volatile liquefied iuel gases like butane from storage tanks, a service pipe connected to the upper portion of the tank for delivering fuel gas from the tank to a point of demand, a liquid pump having its inflow side connected to the lower portion of the tank, a vaporizer connected to the discharge side of the pmnp, a vapor iiow connection between the vaporizer and the service pipe, and means au= tomaticaliy operative responsive to cooling of the storage tank below a predetermined temperature operating said pump.

2. in apparatus for dispensing volatile liquefied iuel gases like butane from storage tanks, 2. service pipe connected to the upper portion of the tor normally delivering fuel gas to a point or" demand, a liquid pump having its inflow side connected to the lower portion of the tank, a vaporizer connected to the discharge side of the pump, a vapor new connection between the vaporizer anrlfithe service pipe, a check valve in the service line between the point of connection of said line with said tank and the point of connection to said vapor flow connection, said check valve serving to prevent back flow of gas from.

' the vaporizer to the tank, andmeans operative responsive to cooling of the storage tank below a predetermined temperature for energizing the pump.

3. In apparatus for dispensing volatile liquefied fuel gases like butane from storage tanks, a service pipe connected to the upper portion of the tank for delivering fuel gas to a point of demand, a. liquid pump having its inflow side connected to the lower portion of the tank, a vaporizer connected to the discharge side of the pump, said vaporizer including electrical heating elements, a vapor flow connection between the, vaporizer and the service pipe, a check valve in the service pipe between the point of connection to the tank and point of connection to said vapor flow connection, whereby back flow of vhpor from the vaporizer to the tank is prevented, an electricalcircuit servme when closed to energize the pump and to supply current to the electrical heating elements of the vaporizer, and thermostatic means responsive to the temperature of the storage tank for automatically controlling supply of current to said circuit, said thermostatic means being set to supply current to said circuit responsive to coolin of the storage tank to a relatively low temperature.

4. In apparatus for dispensing volatilediquefied vapor flow connection between the vaporizer and the service pipe, normally closed valve means for controlling flow of liquefied fuel from the pump to the vaporizer, and thermostatic means responsive to the temperature of the heating elements for opening said valve means when the tempera= ture of said heating elements has attained avalue sufiicient to vaporize the liquefied fuel.

5. in apparatus for dispensing volatile liquefied fuel gases like butane from storage tanks, 2, service pipe connected ii the upper portion of the tank for delivering gas to a point of demand, an electric motor driven pump having its inflow side connected to the lower portion of the tank, a

vaporizer connected to thedischarge side of the 'pump, the vaporizer including electrical heating elements, a vapor flow connection between the vaporizer and the service pipe, a check valve in the service pipe between the point of connection to the tank and the point of connection with said flow connection, whereby vapor from the vaporizer cannot flow hack to the storage tank, a normally closed valve serving to control flow of liquefied fuel from the pump to the vaporizer, thermostatic means for moving said last named valve to open position, said thermostatic means operating responsive to the temperature of said electrical heating elements whereby the valv means ismoved to open position when the heating elements have a, rise in temperature suflicient to vaporize the liquefied fuel, a common electrical circuit for the motor of the pump and for said electrical heating elements, and thermostatic switching means serving to supply or interrupt supply of electrical energy to said circuit, said switching means being responsive to the temperature of said storage tank and being operative to supply current to said circuit when the storage tank is cooled to a relatively low temperature.

6. A vaporizer for liquefiedvolatile hydrocarbons comprising a closed vaporizing chamber, a pipe connected to the vaporizer for introducing a liquefied hydrocarbon, a-valve serving to-control flow of liquid through said pipe, an electrical heating element within said chamber, thermostatic valve operating means within said chamber,

means forming a motion transmitting connection between the thermostatic means and the valve,

9. fusible link interposed in said connection, and

a vapor discharge pipe connected to the vaporizer.

- ARTHUR J. KERCHER.

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