US2138989A - Automatic change-over device - Google Patents

Description

Dec. 6, 1938. R. wfTl-lomAs ET L 2,138,989 AUTOMATIC CHANGE-OVER DEVICE Filed sa py 1957 \JZWQWM Q r I INVENTOR.

'ROSSWELL w. THOMAS CHARLES MAC SPORRAN BY, k MAMu, Q

A TTORNEYS.

Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE MacSporran,

Detroit,

Mich assignors to Phillips Petroleum Company, a corporation of Delaware Application September 14, 1937, Serial No. 163,842

6 Claims.

The present invention relates to improvements in devices for automatically changing withdrawal connections from one source of high pressure gas to another upon decrease in pressure in the first source.

The usual two drum system for bottled gas distribution comprises a pair of cylinders containing liquefied gas, and a service line to the gas consuming appliance connected through a pressure reducing regulator to both the cylinders. Some means is provided for having one -or both of the cylinders turned on at one time in order to supply gas to the regulator and service line and it is necessary to be able to disconnect and replace either cylinder without loss of gas and preferably without too much manipulation of valves or other mechanism. Prior practice has been to open the valve on the active cylinder while keeping the valve on the reserve cylinder closed. When the gas in the active cylinder became exhausted the valve on that cylinder was closed and the valve on the reserve cylinder opened. This series of steps was necessary to prevent the high pressure gas in the reserve cylinder from feeding into the exhausted cylinder. The result was that there was a cessation of the gas supply to the gas consuming appliances and all pilot lights were extinguished. Further in order to remove and replace the exhausted cylinder with a new reserve cylinder, it was necessary to close the valve in the active cylinder in order to prevent escape of its gas into the atmosphere again resulting in a cessation of. the gas supply to the appliances.

To rectify this situation automatic change-over devices were developed such as those shown in U. S. Patents Nos. 1,960,466, issued toWalter I. Thrall, and 2,047,338, issued to one of the present inventors, but these devices are complex and expensive.

The present device is a simple and inexpensive means of automatically accomplishing the change-over from an exhausted cylinder to the reserve cylinder without cutting off the supply of gas to the appliances.

An important object of the invention is to provide a simple inexpensive change-over device.

An additional important object is to provide a change-over device which will operate on a predetermined pressure differential between the two This invention is an improvement over that disclosed in application Serial No. 163,841 filed September 14, 1937, with Rosswell W. Thomas as inventor.

In the drawing forming a part this specification, and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a view in elevation showing a system embodying the present invention,

Fig. 2 is a sectional view of .the manifold,

Fig. 3 is a view partly in elevation and partly in cross section of the manifold in the neighborhood of the diaphragm assembly, and

Fig. 4 is a sectional view of. the diaphragm assembly with part of the spool broken away.

Referring to Fig. l of the drawing, reference numerals, 6, 6 indicate cylinders for containing the liquefied gas. Valves 1, I normally close these containers and have couplings 8, 8' for connection to withdrawal pipes 9, 9. Pipes 9, 9' terminate in a manifold it which in turn is connected to a consumer service or supply line H. Interposed in line ll is a regulator 12 for controlling the pressure of the gas to be fed to the appliances at the other end of the service line. It will be evident from further description that pipe 9, manifold Ill and pipe 9' together constitute a conduit connecting the two cylinders 6, 6 and that service line .II is taken off this conduit at manifold 10. With the above connections completed, valves I, .7 can be opened. Then service line I I, depending upon the position of the valves in manifold l0 as later described,

will draw gas from either of the cylinders 6, 6.

Referring to Fig. 2 which shows an enlarged sectional view of manifold 10, reference numeral l3 designates a modified pipe elbow having threaded pipe coulings l4, l5. Screw threaded into elbow I3 is a fitting l6 having a threaded pipe coupling l1. Pipe couplings l4 and I! open into a chamber l8, formed by elbow l3and fitting l6, through orifices l9 and 20 respectively, while coupling l5 opens into the chamber through bore 2| and groove 22. Valve seats 23 and 24 are formed around the periphery of orifices l9 and 20 on the chamber side. A pair of valve sleeves 25, 26 are slidably mounted in chamber I 8, the valve sleeves being hexagonal in cross section to allow flow of gas past them. Each valve sleeve 25, 26 is further formed with a valve face to co-act with valve faces 23, 24 in the form of resilient disks 25', 26'. Chamber I8 is enlarged at 21 to receive a diaphragm assembly comprising a spool 28 which acts as a guide for a slidable hollow connector 29. A pair of diaphragms 30, 3|

is thus evident that this assembly divides chamher l8 into three parts, the middle part being hermetically sealed from the other two which are in communication with each other through hollow connector 29. A pair of springs 34, 35 are positioned in chamber 18 between the connector and the valve sleeves 25, 28. In the rear of elbow I3 is a screw threaded opening 38 through which passes a spindle 31 held in place by a gland 38. The inner end of spindle 31 passes through spool 28 and terminates adjacent connector 29. At this point the inner portion of spool 28 is cut away to expose connector 29 and the connector is slotted at 39 to receive an eccentric 40. On the exterior end of spindle 31 is positioned a lever 41 fixed with respect to thespindle by nut 42.

The springs are so designed that with the connector in the position shown in Fig. 2 each spring presses with equal force on its valve sleeve. Thus with containers 6, 8' full of liquefied gas and valves 1, I in open position, gas will feed equally from each container into service line II. This usually is not desirable since both containers will become exhausted at about the same time. In normal operation, considering that it is desirable to draw gas from, container 6 while maintaining container 6' in reserve, the lever 4| is turned clockwise through degrees thereby through eccentric 48, moving connector 29 to the right and compressing spring 35 while relieving pressure on spring 34. The parts are so designed that the bias on spring 35 will be, for example, such that an eleven-pound pressure drop will occur across valve 28 while the bias on spring 34 will result in a one-pound pressure drop across valve 25. Assuming that the pressure in each container is one hundred pounds, it will be apparent that the pressure in chamber I8 will be ninety-nine pounds due to the onepound pressure drop across valve 25. Since this leaves only one pound difierence in pressure acting upon valve face 26', this valve will remain closed because eleven pounds difference in pressure is necessary to open it. When container 5 approaches depletion the pressure in chamber l8 will begin to drop. When the pressure has dropped to eighty-nine pounds, valve 25 will open. The decreasing pressure in container 8 will allow valve 25 to close. At the customer's convenience container 6 can then be replaced by a full conainer. If valve I is now opened it will be seen that valve 25 will open and valve 28 close since the same conditions are present as originally, namely one hundred pounds pressure in both containers. This is highly undesirable because the customer will have no way of I telling how much gas remains in container 5'. The ideal situation would be to have the new container 6 as a reserve container to be connect- 1 vention, herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of this invention and further that the theories of operation set out, although believed to be accurate are not to be considered as the sole basis of the operativeness of this device but that this device does operate successfully whether or not upon the principles describedherein, this invention to be limited solely by the appended claims.

We claim:

In a system for storing and utilizing high pressure fuel gas, the combination comprising a pair of containers for said gas, a conduit connecting said containers together, a consumers service line connected to said conduit, a pair of valves in said conduit, one on each side of said service line, each said valve being biased to close said conduit against pressure in each said container, said valves openable by pressure in said containers, and means for varying the bias on each said valve so that whichever one said valve desired will present a greater resistance to gas flow than the other.

In a system for storing and utilizing high pressure fuel gas, the combination comprising a pair of containers for said gas, a conduit connecting said containers together, a consumers service line connected to said conduit, a pair of valves in said conduit, one on each side of said service line, each said valve being biased to close said conduit against pressure in each said container, said valves openable by pressure in said containers, and a movable member operable from the exterior of said conduit for varying the bias on each said valve so that whichever one said valve desired will open before the other.

3. In a system for storing and utilizing high pressure fuel gas, the combination comprising a pair of containers for said gas, a conduit connecting said containers together, a consumer's service line connected to said conduit at a point intermediate said containers, a pair of valves in said conduit onev on each side of said point, a spring acting upon each said valve for biasing said valve closed against pressure in said container, said springs being separated from one another by a movable member, and means exterior of said conduit for actuating said movable member to vary the relative bias on said valves.

4. A manifold for use in high pressure fuel gas systems wherein a pair of containers for said gas are connected to a consumer's service line, comprising a body portion having a chamber with a pair of gas inlets for connection with said containers and a gas outlet for connection with said service line, a pair of valves for closing said inlets systems wherein a pair of containers for said gases are connected to a consumers service line, comprising a body portion having a chamber with a pair of gas inlets for connection with said containers and a gas outlet for connection with said service line, a pair of valves for closing said inlets against pressure in said containers, a movable member in said chamber intermediate said valves, spring means in said chamber biasing said valves into closing position, said movable member having co-action with said spring means where-' a a,1ss,ase by the bias on each said valve can be varied rela- ,azainst pressure in said containers, a movable tive to the other.

8; A manifold for use in high pressure iuelsas member in said chambef between said valves, a spring between each valve and said projecting member for biasing said valves into closed position, and means exterior of said manifold for actuating said movable member, whereby the relative biasing action 'of .said springs can be varied.

ROSSWELL W. THOMAS.

CHARLES MACSPORRAN.

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