US 2138988 A
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Dec. 6, 1938. R. w. THOMAS AUTOMATIC CHANGE-OVER DEVICE Filed Sept. 14, 1937 .M MM ww TO E NH CN T um T WW u A E u\ w m R l L BH Q mm, m? M mv Om wm vm.
Patented Dec. 6, 1.938 i ananas annemarie @rE-OVER. DIEVHCE W. Thomas, im.
A gnor Vte Pps Petrole Conny, a cor- Y pcranon of mieiaware Application @mi i llii, 193'?, No. ldiidi 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 5 first source.
The usual two drum system for bottled gas distribution comprises a pair of cylinders containing liqueiied gas, and a service line 1to the gas consuming appliance connected through a i@ 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. Whenthe 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 con suming appliances andall pilot lights were extinguished. Further in order to remove and replace the exhausted cylinder Vwith 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 oi the gas supply to the appliances. 1
To rectify this situation automatic change-over devices were developed such as those shown in U. S. Patents Nos. 1,960,466, issuedto Walter I. Thrall, and 2,047,338, issued to Rosswell W. Thomas, but these devices are complex and expensive. e 'Y The present device, isla simpleand inexpen- (Ui. 62nd.)
Figs. 2, 3 and 4 are cross sectional views of three modifications of amanifold valve, and
Fig. 5 is a view in cross section taken on the line 5 5 in Fig. 2.
v Referring to Fig. l of the drawing, reference 5 numerals t, t indicatecylinders for containing the liqueded gas. Valves l, i normally close these containers and have couplings d, t' for connection to withdrawal pipes d, d. Pipes t, d'
i terminate in a manifold i@ which in turn is conit nected to a consumer service or supply line il. interposed in line il is a regulator i2 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 l5 pipe 9, manifold lil and pipe d' together con-s stitute a conduit connectingthe two cylinders t, t and that service line il is taken od this conduit at manifold ill. With the above connections completed, valves 1,' 'l' can be opened. Then E@ service line il, depending upon the position of the valves in manifold it as later described, will draw gas from either of the cylinders 8,' G'.
Referring to Fig. 2 which shows an enlarged sectional view of manifold it, reference numeral 25 i3 designates a modied pipe elbow having threadedpipecoupllngs i4, l5. Screw threaded into elbow I3 is a tting I6 having a. threaded pipe coupling I1. Fitting I6 and elbow i3 together form a. chamber I8 which has a perf0- 30 sive means oi automatically accomplishing the change-over from an exhausted cylinder to the 4s reserve cylinder without cutting oil the supply oi' gas to the appliances.
An important object of the invention is to provide a simple inexpensive change-over `dev1ce. W An additional important object is to provide a determined pressure differential between the two cylinders in the system.
Fig. i is a view in elevation showing the relative position of the cylinders, valve connections, manifold valve and regulator,
change-over device which will operate on a prerated partition I 9 therein. Partition I9 isheld in place by the screw threaded joint between ttlng IB and elbow I3. Thepartitlon is formed of nbervor some'resllient material so that ,it further constitutes a gasket to seal the joint'. Pipe 35 couplings I4 and I1 open into chamber I8 through orifices 2U and 2| respectively and coupling I5 has a passage I5' opening intochamber Il. the orifices and passage constituting inlets and yan outlet, respectively, for the chamber` Il. Valve seats 22 and 23 are formed around the periphery n o! orifices 20 and 2| on thechamber side. A pair o! valvesleeves 2l, 25 are slldably mounted in chamber I8. As shown in AFig. 5, valve sleeve 25, which is identical "with valve sleeve 24 al- 45. though reversed in position, is provided with radially extending uns -26 which serve as guides for the valve in its 'sliding mov/ement. in chamber I8 and provide a space between the walls of chamber Il and the periphery of the valve sleeve to permit the flow of gas past the' valve sleeve when the latter is open. Each valve sleeve 24, 2l ls further ormedwith a valve face to coact with valve faces 22 and 2l, in the form of resilient. disks 21, 28. Apair of springs 20, I0 an pod- 55'.
tioned between partition I9 and each valve to bias the valves' into closing position, the two springs 29, 30 being formed of equal length whereby, when they are positioned in the chamber, one spring, as shown in spring 30, will be compressed to a greater degree than the other spring 29 due to the position of partition I9. As a result valve 25 will have a greater bias than valve 2d.
With manifold l0, as shown in Fig. 2, mounted in the system of Fig. 1, it will be evident that pipe coupling I4 will be threadedly engaged with pipe 9 and pipe coupling I1 will be threadedly engaged with pipe 9'. Service line II and regulator I2 will be threadedly engaged with pipe coupling I5. In the operation of the device, assuming that cylinders 6 and 6 are both filled with liquefied gas andv thelambient temperature is such that the pressure present in both cylinders is one hundred pounds per square inch, springs 29 and 30 can be so designed that iiow of gas through orifice 20 will encounter a one-pound pressure drop and iow of gas through orifice 2l will encounter an eleven-pound pressure drop, giving a ten-pound pressure differential between the two valves. On opening valves 'Iy and 1 with the resulting application of the gas pressure in the cylinders 6, 6 to valve faces 21 and 28 respectively, both these latter valves will tend to open against their respective biases. Flow of gas through orifice 20 will result in a pressure of ninety-nine pounds in chamber I8 due to the one-pound pressure drop around valve 24. With a pressure of ninety-nine pounds in chamber I8 and a pressure of one hundred pounds on valve face 28, it will be apparent that the resulting one-pound pressure exerted upon valve 25 will be insuflicient to open the valve and that cylinder '6 will be solely drawn upon to furnish gas to the service line II. When the liquefied gas in cylinder 6is depleted, the pressure in the cylinder will begin to drop. When the pressure has dropped to ninety pounds, it will be seen that the pressure in chamber I8 will be eighty-nine in view of the one-pound pressure drop still present around valve 24. With the pressure in chamber I 8 at eighty-nine pounds there will be a pressure differential of eleven pounds across valve 25 which, under the conditions set forth above, will open this valve. Since the pressure in cylinder 6 is constantly dropping while the pressure in I8 is maintained at eighty-nine pounds by the flow of gas through orice 2t, valve 24 will close because the pressure in the chamber I8 Awill be above the pressure in cylinder 6. Depleted cylinder 6 has therefore been disconnected from service line II while iilled cylinder 6 has been connected thereto.
Referring to Fig. 3, a modication of manifold I is shown. In this construction a T-iitting 3l having a pipe coupling 32 has screw threaded into each end thereof fittings 38, 34. The joints are sealed by gaskets 35, 36. Each tting 33, 34 has a tube coupling 31, 38 respectively, having passages 39, 49 terminating in orifices 4I, 42 surrounded by valve faces 43, 44. T-fltting 3l and fittings 33, 34 form a chamber 45, corresponding to chamber I8 in Fig. 2, in which are slidably disposed valves 46, 41, identical with valves 24 and 25 of Fig. 2. T-iitting 3| carries a projecting member 48 which projects into chamber 45. A
` pair of springs 49, 50 are positioned between pro- Fig. 2, one of the springs, for instance spring 50, is heavier and stiffer than the other so as to exert a greater bias on valve 41 than the other spring 49 exerts on valve 46. Here again the design of the springs can be such as to cause a one-pound pressure drop across valve 46 and an eleven-pound pressure drop across valve 41. The operation of this modification is identical with that of Fig. 2.
'I'he manifold of Fig. 4 is of similar construction to that of Fig. 2 except that partition I9 has been omitted resulting in the necessity of a gasket I between elbow I3 and fitting I6. In this modification only one spring 52 is used between valves 24 and 25 but orifice 20 is formed with a greater area than orifice 2|. The relative sizes of orices 20 and 2i can be such that there is a one-pound pressure drop around valve 24 and an eleven-pound pressure drop around valve 25 resulting in the same operation as in Fig. 1.
It is to be understood that the form of my invention 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 my 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 my device but that my device does operate successfully whether or not upon the principles described herein, my invention to be limited solely by the appended claims.
l. 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 at a point intermediate said containers, a pair of valves in said conduit one on each side of said point, a spring acting upon each said valve for biasing said valve closed against pressure in said container, one of said valves having a greater bias than the other.
2. A manifold for use in high pressure fuel gas systems wherein a pair of containers for said gas are connected to a consumers service line for withdrawal of said gas from consecutive containers, comprising a body portion having a chamber with gas inlets for' communication with said containers and a gas outlet for communication with said service line, a pair of valves movable in said chamber, each of said valves biased to close a said inlet, said valves being openable by pressure in said containers, one of said valves being designed toI open before the other said valve.
3. A manifold for use in highA pressure fuel gas systems wherein a pair of -containers for said gas 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, valve means in said chamber for closing either of said inlets, one of said inlets having a greaterl area than the other said inlet.
4, A manifold for use in high pressure vfuel gas systems wherein a Vpair of containers for said gas 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, spnng means for biasing said valves into closing position, said spring means exerting a greater bias on one of said valves than on the other said valve.
5. A manifold for use'in high pressure fuel gas systems wherein a pair of containers for said gas are connected to a consumers service line, com prising a body portion having a chamber with a pair of gas inlets for lconnection with said containers and a gas outlet for connection with said service line, a pair ofva1ves for closing said inlets against pressure in said containers, a projecting member in said chamber between said valves, a spring between each valve and said projecting member for biasing said valves into closed position, the biasing action of one said spring being greater than that of the other.
6. In a system for vstoring and utilizing high pressure fuel gas, the combination comprising a pair of containers for said gas, a conduit connecting lsaid containers together, a consumers` service line connectedto .said conduit, a pair of 5 to present a greater resistance to gas ow than 10 the other said valve.
V ROSSWEIL W. THOMAS.'