US3407616A - Vaporizer for fuel gases - Google Patents

Description

Oct. 29, 1968 w. P. FREEMAN, JR 3, 0 ,6

VAPORIZER FOR FUEL GASES Filed Oct. 17, 1966 2 Sheets-Sheet 1 lr/VENTORJ W/L 1. 1AM P. FREEHAALJR.

United States Patent 3,407,616 VAPORIZER FOR FUEL GASES William P. Freeman, Jr., Dallas, Tex., assignor to John E. Mitchell Company, Dallas, Tex., a corporation of Missouri Filed Oct. 17, 1966, Ser. No. 587,231

Claims. (Cl. 62--51) ABSTRACT OF THE DISCLOSURE A vaporizer of the kind having a vaporizing chamber for generating vapor to supply the normal demands of consuming apppliances and having an auxiliary vapor source for supplying excess demands. A valve arrangement for controlling the flow of vapor from the vaporizing chamber and from the auxiliary vapor source according to variations in demand and for preventing liquified petroleum from being delivered to the consuming appliances.

Brief description of the invention This invention is an improvement upon U.S. Patent No. 2,551,501, assigned to the John E. Mitchell Company, assignee of the present invention. In the present invention, a vaporizing chamber is connected to receive liquid petroleum from :a storage tank. Conventional burner means are provided for heating liquid petroleum in the vaporizing chamber and boiling oif petroleum vapor. Vapor from the vaporizing chamber passes through a float chamber (which is part of the vaporizing chamber) and past a valve seat to an outlet chamber from which it can be supplied to consuming appliances. A float assembly in the float chamber controls the position of a valve member which throttles the flow of vapor from the float chamber under excess demand conditions when the liquid level within the float chamber rises.

A pipe is connected from the upper side of the storage tank to deliver auxiliary petroleum vapor to the outlet chamber. A valve is positioned between the auxiliary vapor supply pipe and the outlet chamber, and a spring holds the'valve closed until the pressure differential on opposite sides of the valve is sufficiently high to open the valve. This pressure differential is a function of the demand of the consuming appliances so that, as the demand becomes excessive, the pressure within the outlet chamber is reduced to create the required pressure differential to open the auxiliary vapor supply valve.

An object of this invention is to provide a vaporizer having a vaporizing chamber for supplying vapor to an outlet chamber from which the vapor is delivered to consuming appliances, and an auxiliary vapor source connected to supply auxiliary vapor to the outlet chamber, with a float valve for simultaneously preventing the flow of liquid from the vaporizing chamber to the outlet chamber and throttling the flow of vapor when the demand is excessive, and with an independently mounted valve for regulating the flow of vapor from the auxiliary vapor source as a function of variations in demand measured as variations in pressure differential on opposite sides of the independently operable valve.

Another object of the invention is to provide a vaporizer having a vaporizing chamber and having a storage tank for supplying liquid petroleum to the vaporizing chamber and for supplying auxiliary vapor to augment the vapor supplied from the vaporizer chamber to meet excessive appliance demands, with valve means to regulate the flow of vapor from the vaporizing chamber and the storage tank so designed as to permit side variations in the height of installation of the vaporizing chamber relating to the storage tank.

Another object of the invention is to provide a vaporizer 3,407,616 Patented Oct. 29, 1968 having .a vaporizing chamber and an auxiliary vapor supply tank with valve means for regulating the supply of vapor from the vaporizing chamber and the auxiliary vapor source, where the valve means are easy to assemble and are quickly and sensitively responsive to change in vapor demand.

Other objects and advantages will be apparent to those skilled in the art.

Brief description of the drawings FIGURE 1 is a top fragmentary plan view of the vaporizer;

FIGURE 2 is a fragmentary side elevation view of the Detailed description of the invention This invention is an improvement on U.S. Patent No. 2,551,501, granted on May 1, 1951, to Orville Mitchell and William P. Freeman, Jr., and assigned to the assignee'of the present invention. As in the earlier Mitchell et al. patent, the present invention comprises a vaporizing chamber 10 connected through a pipe 11 to a storage tank 12. The storage tank 12 holds a volatile substance that is stored primarily in the liquid state up to a liquid level above which the substance is in a vapor stage, as is conventional. A shutoif valve 13 in the pipe 11 remains open during operation of the vaporizing apparatus.

A float chamber 15 is mounted above the vaporizing chamber 10 and is in open communication with the vaporizing chamber. A pair of ball floats 16 and 17 are connected together by a suitable connector 18 and are positioned within the float chamber 15 to move vertically of the float chamber 15. The plate 25 has an opening 27 through its center for receiving the lower end 28 of a valve housing 29. The valve housing 29 is fastened to the plate 25 by a plurality of bolts 30. The valve housing 29 has a shoulder 31 overlying the plate 25 that presses against a gasket 32 when the bolts 30 are tightened.

The valve housing 29 has a passage 33 through it having internal threads 34 at its upper end and a valve chamber 35 of reduced diameter at its lower end. An O-ring 37 is mounted in a groove 38 in the inner side wall of the valve chamber 35 adjacent its lower edge. The diameter of the O-ring 37 is less than the largest diameter of the valve face 22 of the valve member 21 and the O-ring acts as the valve seat for the valve member 21.

A valve housing 40 is threaded onto the upper end 41 of a pipe 42 that in turn is threaded into the internally threaded opening 34. The pipe 42 has a passage 43 through it leading to an outlet chamber 44 within the valve housing 40. A pipe 45 is threaded into an outlet port 46 which communicates with the outlet chamber 44. The pipe 45 is connected through suitable pressure regulator means to a consuming appliance, neither of which is shown in the drawings. Another pipe 47 is connected to another outlet port 48 communicating with the outlet chamber 44. The pipe 47 is connected through a shutoff valve 49 to an- 3 other pipe 50 that leads through a suitable pressure regulator means to a burner means for heating the tank 10. Neither the pressure regulator means nor the burner means are shown in the drawings.

A valve sleeve 51 is threaded into another opening 52 through a side of the valve housing 40. The valve sleeve 51 has an inlet chamber 53 in communication with an inlet port 54. A pipe 55 connects the inlet port 54 to the upper side of the supply tank 12 through a shutolf valve 56.

A ring 58 is mounted within the valve chamber 53. The ring 58 has a central tubular opening 59 through it and a plurality of additional openings 60 through it spaced radially outwardly from the tubular opening 59. A valve member 62 having a beveled valve face 63 is threaded onto the end 64 of a valve stem 65. The valve stem 65 is slidable within the opening 59 in the ring 58 to move the valve face 63 toward and away from a valve seat 66 defined by the annular edge of the inlet chamber 63.

A nut 67 is threaded onto the other end 68 of the valve stem 65. A compression spring 69 is mounted between the ring 58 and a shoulder 70 on the nut 67 to bias the valve member 62 toward a closed position against the valve seat 66. The force of the spring 69 may be varied for different installation conditions as will be described, but it is ordinarily within the range equivalent to about one pound per square inch on a side of the valve member 62.

Operation For operating this vaporizer, the storage tank 12 contains a relatively large reserve supply of liquefied petroleum with petroleum vapor above the liquid level in the upper section of the tank 12. With the valve 13 open, the pipe 11, which is connected to the tank 12 below the liquid level of petroleum within the tank 12, admits liquid petroleum to the vaporizing chamber 10. Initially, opening of the valve 56 admits vapor from the storage tank 12 to the burner pipe 50, because when the burners are opened to draw from the outlet chamber 44, in a manner known in the art, pressure within the outlet chamber 44 is reduced sufliciently to overcome the spring force 69 and permit the valve 62 to open.

As the liquid petroleum within the vaporizing chamber is heated, it vaporizes, and the vapor flows through the float chamber to the outlet chamber 44 raising the pressure within the outlet chamber 44 until the com- .pression spring 69 draws the valve member 62 against the valve seat 66. With the valve face 63 of the valve member 62 seated against the valve seat 66, the flow of vapor from the storage tank 12 is blocked.

Under normal operating conditions, the valve 62 remains closed, as normal demand of appliances connected to the outlet pipe 45 can be supplied from vapor generated at the vaporizing chamber 10. Variations within the normal demand range cause the liquid level within the float chamber 15 to rise and fall, but the accompanying rising and falling of the floats 16 and 17 does not bring the valve member 21 significantly close to the valve seat 37. Thus, decreases in demand of the consuming appliances permit the vapor pressure within the outlet chamber 44 and the float chamber 15 above the liquid level therein to increase above the vapor pressure within the storage tank 12. This drives some of the liquid from the vaporizing chamber back to the storage tank 12 through the pipe 11 until the vapor pressures are equalized (or equilibrium is reached between unequal vapor pressures). Falling of the liquid level within the float chamber 15 reduces the surface contact area between the float chamber walls and the liquid within the float chamber, so less vapor is produced to supply the reduced appliance demand.

The reverse action occurs when demand of the consuming appliances increases. Then, as more vapor is drawn off by the consuming appliances, the pressure within the outlet chamber 44 and the float chamber 15 is reduced.

This causes the vapor pressure within the storage tank 12 to drive more liquid petroleum through the pipe 11 to the vaporizing chamber 10, raising the liquid level within the float chamber 15 and increasing the area of contact between the walls of the float chamber 15 and the liquid within the float chamber. Hence, more of the liquid petroleum is heated and boiled off as vapor to supply the higher demand.

The floats 16 and 17 follow the rising and falling liquid level within the float chamber 15, but for fluctuations in demand within the normal operating range, the valve member 21 remains at a distance from the valve seat 37. Therefore, there is no significant pressure drop past the valve seat 37, and the force of the spring 69 holds the valve face 63 of the valve member 62 against the valve seat 66. However, when the demand of appliances connected to the pipe 45 become excessive and above that which can be supplied by the vaporizing chamber 10, the pressure within the outlet chamber 44 and the float chamber 15 decreases still further and the liquid level within the float chamber 15 rises further, moving the valve member 21 nearer to the valve seat 37. As the valve face 22 approaches the valve seat 37, the flow of vapor from the float chamber 15 is throttled, creating a pressure drop, reducing the pressure within the outlet chamber 44. When the pressure differential between the vapor supplied from the storage tank 12 through the pipe 55 and the pressure within the outlet chamber 44 is greater than the equivalent pressure produced by the spring 69, the valve member 62 is moved away from the valve seat 66, and auxiliary vapor is supplied from the storage tank 12. The auxiliary vapor flows from the storage tank 12 through the pipe 55 and the openings 60 in the ring 58 to the outlet chamber 44.

When the appliance demand again reduces to a normal demand range, the pressure within the outlet chamber 44 increases to a value sufiicient to permit the spring 69 to close the valve member 62 against the valve seat 66 and to drive the liquid level within the float chamber 15 down to move the floats 16 and 17 down and the valve face 22 away from the valve seat 37. Accordingly, the vaporizer again operates to supply the demands of the appliances without drawing vapor from the storage tank 12.

Even under excessive demand conditions which cause the valve face 22 to move near the valve seat 37 and throttle the flow of vapor, or even to seat against the valve seat 37 and completely block the flow of vapor from the float chamber 15, the valve member 62 may move back and forth between open and closed positions. Thus, the reduced pressure condition within the outlet chamber 44 caused by the excess demand causes the valve member 62 to move away from the valve seat 66 and admit auxiliary vapor from the storage tank 12 to the outlet chamber 44. However, this auxiliary vapor supply within the outlet chamber 44 increases the pressure and tends to close the valve member against the valve seat 66. In addition, as the flow of vapor from the vaporizing chamber 15 is throttled or blocked, vapor pressure within the float chamber 15 increases, tending to lower the liquid level within the vaporizing chamber 15 and move the valve face 22 away from the valve seat 37. These fluctuations occur automatically with the variations in demand and with the internal pressure variations affecting the positions of the two valve members 62 and 21. The effect is to supply vapor from the float chamber 15 as produced by the vaporizing chamber 10 during periods of normal demand without drawing from the storage tank 12, and yet to meet the excess demands with auxiliary vapor supplied from the storage tank 12.

The spring 69 may be changed to provide varying spring forces tending to close the valve member 62 against the valve seat 66. For example, the spring 69 may be designed with a force equivalent to approximately one pound per square inch differential on opposite sides of the valve member 62 when the vaporizing chamber is to be located on approximately the same level as the storage tank 12. However, the invention permits Wide variations in location of the vaporizing chamber 10 relative to the tank 12. For example, to locate the vaporizing chamber at higher level above the tank 12, the spring 69 is simply replaced with a similar spring having a greater spring force.

The assembly of the valve parts within the valve sleeve 51 is quite easy and can be completed before the sleeve 51 is installed in the valve housing 40. The sleeve 51 is, of course, easily installed by simply threading it into the opening 51 in the valve housing 40 to the position illustrated in FIGURE 5.

Various changes and modifications may be made within the purview of this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

1. A vaporizer comprising a vaporizing chamber, a storage tank, means for delivering liquid from the storage tank to the vaporizing chamber to be boiled to create vapor, first pipe means for delivering vapor from the vaporizing chamber to an area of demand for the vapor, normally open first valve means in the first pipe means for throttling the flow of vapor from the vaporizing chamber when the demand for vapor exceeds the capacity of the vaporizing chamber to supply vapor, means to close the first valve means upon decrease in pressure below a predetermined value downstream of the first valve means, an auxiliary vapor source, a second pipe means for conveying vapor from the auxiliary vapor source to the first pipe means, and pressure responsive normally closed valve means in the second pipe means for regulating the flow of vapor through the second pipe means, the pressure responsive valve means having a valve controlling element with one face exposed to pressure in the first pipe means, and another face exposed to pressure in the second pipe means, a valve seat in the path of movement of the valve controlling element, the valve controlling element being movable toward the valve seat in response to increase in pressure in the first pipe means relative to pressure in the second pipe means, and being movable away from the valve seat in response to decreases in pressure in the first pipe means relative to pressure in the second pipe means thereby rendering the pressure responsive valve means operable in response to variations in the vapor pressure in the first pipe means caused by variations in demand.

2. The vaporizer of claim 1 including means to main tain the pressure responsive valve means in closed position to block the flow of vapor through the second pipe means when the demand for vapor is within the capacity of the vaporizing chamber to supply vapor and to open the pressure responsive valve means when the demand for vapor is greater than the capacity of the vaporizing chamber to supply vapor.

3. The vaporizer of claim 1 wherein the first valve means comprises a valve seat between the vaporizing chamber and the first pipe means, and a valve member movable toward and away from the valve seat in response to variations in the volume of liquid within the vaporizing chamber.

4. The vaporizer of ,c'laim 3 including a float floating within the liquid in the vaporizing chamber, the valve member of the first valve means being mounted on the upper side of the float, means to restrict the float to substantially vertical movement as the liquid level within the vaporizing chamber varies, the valve member having an upper concave valve face, the valve seat comprising an annular resilient member against which the valve face is adapted to seat upon rise of the liquid level within the vaporizing chamber in response to excessive demands for vapor.

5. The vaporizer of claim 1 wherein the pressure responsive valve means comprises a valve seat positioned between the first and second pipe means, a valve member movable toward and away from the valve seat, the valve member having a side exposed to vapor pressure within the first pipe means so that increases in vapor pressure within the first pipe means tend to move the valve member toward the valv seat, the valve member having another side exposed to vapor pressure within the second pipe means so that increases in vapor pressure within the second pipe means tend to move the valve member away from the valve seat, and a spring means for biasing the valve member toward the valve seat.

6. The vaporizing chamber of claim 5 including a valve housing having an outlet chamber, the first pipe means including means for establishing communication between the outlet chamber and the first valve means and means for establishing communication between the outlet chamber and the demand area, the second pipe means including means for establishing communication between the auxiliary vapor source and the outlet chamber through the pressure responsive valve means, the pressure responsive valve means including a valve sleeve threaded into the valve housing and having a passage through it, the valve member, valve seat and spring means being mounted within the valve sleeve the valve sleeve being removable to permit replacement of the valve spring to accommodate different mounting heights of the vaporizing chamber relative to the storage tank.

7. The vaporizer of claim 1 wherein the auxiliary vapor source comprises the upper portion of the storage tank above the level of liquid within the storage tank.

8. A vaporizer comprising a vaporizing chamber, means for supplying vapor from the vaporizing chamber to an area of demand for the vapor, means for supplying liquid to the vaporizer in response to pressure reductions within the vaporizer, normally open valve means for throttling the flow of vapor from the vaporizer in response to decreases in pressure downstream of the valve means caused by vapor demands exceeding the capacity of the vaporizer to manufacture vapor, means to close the first valve means upon decrease of pressure below a predetermined valve downstream of the first valve means, an auxiliary vapor source for supplying auxiliary vapor to the demand area, pressure responsive valve means for controlling the flow of vapor from the auxiliary vapor source, the pressure responsive valve means having a first pressure responsive element exposed to pressure between the demand area and the first named valve means, and a second pressure responsive element exposed to the pressur of the auxiliary vapor source whereby the pressure responsive valve means responds to variations in the pressure differential against its pressure responsive elements to open under conditions of excessive vapor demand and close under conditions of normal vapor demand, the pressure responsive valve means being movable toward closed condition when the pressure of the first element increases relative to the pressure on the second element and toward open condition when the pressure on the first element decreases relative to the pressure on the second element.

9. The vaporizer of claim 8 including a tank containing liquid for supply to the vaporizer, the means for supplying liquid to the vaporizer comprising a pipe between the tank and the vaporizer, the area in the tank above the liquid level therein comprising the auxiliary vapor source, whereby liquid is supplied from the tank to the vaporizer as functions of the pressures within the tank and the vaporizer.

10. The vaporizer of claim 9 including a spring for biasing the pressure responsive valve means toward closed position, means permitting removal and replacement of the spring to enable changes in spring force, the spring force controlling the extent of pressure differential necessary to open and close the pressure responsive valve 7 means, whereby different heights of the vaporizer relative 2,729,948 to the tank may be accommodated by different spring 2,777,296 force installations. 2,873,582 References Cited 2,993,343 5 3,091,096

UNITED STATES PATENTS 2,705,872 4/1955 Thompson 62-51 Northgraves 6251 Schilling 6249 X Green 62-52 X Benz 6251 X Rendos et al 6252 ROBERT A. OLEARY, Primary Examiner.

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