US2346112A - Apparatus for vaporizing liquefied gases - Google Patents

Description

$ mu. Q am l NVENTOR ATTORN EY THEODORE MELSHEIMER April 4, 1944. 'r. MELSHEIMER APPARATUS FOR VAPORIZING LIQUEFIED GASES Filed Sept. 16. 1941 Patented Apr. 1, 1944 APPARATUS FOR VAPORIZING LIQUEFIED GASES Theodore Melsheimer, Temple City, Call1'.. assignor to Parkhill-Wade, Los Angeles, Calif., a corporation Application September 16, 1941, Serial No. 411,090

3' Claims.

The invention relates to means for vaporizing liquefied petroleum gases for delivery in vapor form to consuming systems, as for example domestic gas systems, internal combustion engines, and the like In previous designs of vaporizing systems for such purposes, in which a throttled supply of the liquefied gas is passed to a heated vaporizing means and thence, in vapor form, to the consuming system, it has been necessary to take elaborate precautions to prevent the influx of liquid into the consuming system inthe event of failure or malfunctioning of the heating means. The passage of liquid to the consuming system is likely to be dangerous in the extreme, as causing a tremendous over supply of fuel to the fires and a consequent serious fire hazard.

In order to guard against this possibility it has been common in such systems to provide at the outlet from the vaporizer a chamber containing a fioat arranged to operate a shut-oil valve in the fuel delivery line. With this mechanism a tendency on the part of the vaporizer to overflow liquid causes the float to rise, shutting ofi the entire supply of fuel to the consuming system, thereby avoiding the hazards just described. Frequently the valve controlled by the float is made of the "snap action type, requiring a manual operation by the attendant in order to restore gas service, even though the trouble in the vaporizer is corrected immediately and the liquid level in the fioat chamber subsides.

The principal purpose of the present invention is to avoid entirely the necessity for the overflow protection just described, eliminating the complication and expense which such a system introduces, and at the same time providing a vaporizing system from which it is impossible to deliver fuel in liquid form under any circumstances.

Another object of this invention is to provide simple and inexpensive means for maintaining adequate pressure on the liquid storage tank in such a fuel system during those periods when the temperature of the atmosphere surrounding the storage tank is too low to afford such pressure.

Another object of this invention is to provide a vaporizing system for the utilization of liquefied fuels which vaporizes such fuels by means of atmospheric heat so long as such heat is adequate to maintain the necessary pressure in the delivery system, and which applies artificial heat for vaporizing only during such timesas such natural atmospheric heat is inadequate. By this means the system accomplishes an important saving in fuel which would otherwise be required for vaporization of the liquid fuel alone.

The invention will best be understood with reference to the attached drawing and the following description thereof, in which Fig. 1 illustrates diagrammatically a complete assemblage of apparatus, in which the liquid gas supply to the vaporizer is controlled on the liquid side thereof; and

Fig. 2 illustrates a modification in which the liquid gas supply is controlled indirectly by controlling the vapor stream issuing from the vaporizer.

Referring to the drawing, the three forms have several parts in common. Thus, id .is a delivery pipe leading to any consuming system not shown. Such pressure as is desired in this system is maintained by any preferred pressure regulating device indicated at H. Pipe id communicates with the highest point in a liquid gas supply tank l2, preferably through a relatively tall and narrow vapor dome 113. A liquid gas supply pipe it leads to the lower end of a vaporizing shell which may be heated in any convenient manner, preferably by means of steam entering a jacket I6 through a pipe ill from a source not shown. Water condensing in the jacket is removed in any preferred manner, as by means of a steam trap It. In the modifications of Figs. 1 and 2 any other means of heating may be employed, as for example thermostatically controlled electrical heating coils located within shell l5 and near the lower end thereof.

Supply tank l2 must be located at such height as to provide a material gravity head above the heated portion of shell l5, and the upper end of shell l5 must project materially above the highest possible liquid level in tank l2. A vapor pipe it connects the upper end of the vaporizer with a part of tank l2 above the highest liquid level, preferably with the lower portion of dome l3 which thus acts as a trap to prevent a spray of liquid from being carried into the consuming system in the event of excessive momentary demand.

Now describing the functioning of the form of apparatus shown in Fig. 1, in which a liquid regulating valve 20 is interposed in liquid suppl line M and is made responsive to the pressure in vapor line 19 (as by means of a communicating tube 2|) and therefore to the pressure in supply tank l2. This valve 20 is arranged to open with declining pressure and to close when the pressure rises above a predetermined point.

Assuming now that the system is standing i for example 33# gauge.

Now assuming the beginning oi a demand for vapor: the contents of tank l2 will begin to vaporize and will supply the demand until the temperature of the liquid has become so reduced that the vapor pressure falls below the pressure at which valve 20 is set to open. This reduction in temperature will be more or less delayed by the infiltration of atmospheric heat, and at times or high atmospheric temperature this heat infiltration may produce a supply of vapor adequate to meet the demand.

We will next assume that the atmospheric heat supply is not suiilcient and that the vapor pressure falls more or less rapidly until it reaches the 33# gauge at which valve 20 is set. This valve then opens and admits a gravity flow of liquid to the vaporizer, in which it rises to some level (as at 2!) at which the heating surface covered by liquid is just sufficient to supply the vapor demand of the consuming system. On a reduction in demand, or if valve 20 initially admits an excessive supply of liquid, the liquid level in the vaporizer will rise, covering more heating surface. This in turn causes an increased evolution of vapor, an increase in the vapor pressure in the system, and the partial or complete closing of valve 20. Thus the valve 20 functions to admit to the vaporizer only such supply of liquid as may be required to produce the makeup supply of vapor, i. e., the amount demanded by the consuming system less the amount produced by atmospheric heat entering through the walls of tank i2.

In the form of Fig. 2 the same efiects are accomplished in a slightly different manner by placing a vapor regulating valve 22 in the vapor delivery line l9 and making it responsive to the pressure in the vapor space of tank II, as by means or tube 23. In this form vapor is passed through pipe l9 from the vaporizer whenever the pressure in tank l2 falls below the predetermined figure (assumed above at 33# gauge) and as vapor is released from the vaporizer, liquid gravitates into the lower end or the vaporizer to such height as to provide the quantity of vapor so withdrawn.

On the cessation of demand for vapor, any liquid remaining in the vaporizer of Fig. 1 will be vaporized and pass as vapor into tank l2. In th form of Fig. 2, a cessation of demand will cause an excess vapor pressure in the upper end of the vaporizer which will displace any remaining liquid back into the supply tank.

I claim as my invention: 1. A vaporizing system for liquefied gaseous fuels, comprising: a storage tank for said liquefied fuel; a service channel connecting the vapor space in said tank with a point of consumption of vapor; a pressure regulator interposed in said channel and adapted to maintain a substantially constant pressure at said point, the portion of said channel between said regulator and said vapor space being unobstructed and constantly open; a vertically disposed vaporizer including a vertically extended heating means having a'heated wall, said vaporizer extending both above and below the liquid space in said storage tank; a liquid channe1 affording communication between the lower part of said tank and. the lower part 01' said vaporizer; a vapor channel independent of said service channel afiording communication between the upper portion of said vaporizer and said vapor space in said tank, and throttling valve means responsive to the pressure in said vapor space for controlling the depth of liquid in said vaporizer and the extent to which said heated wall is covered by said liquid.

2. A system substantially as and for the purpose set forth in claim 1, in which said throttling valve means is interposed in said liquid channel.

3. A system substantially as and for the purpose set forth in claim 1, in which said throttling valve means is interposed in said vapor channel THEODORE MELSHEIMER.

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