US1841325A

US1841325A - Means for draining gas cylinders

Info

Publication number: US1841325A
Application number: US328228A
Authority: US
Inventors: George M Deming
Original assignee: Air Reduction Co Inc
Current assignee: Airco Inc
Priority date: 1928-12-24
Filing date: 1928-12-24
Publication date: 1932-01-12
Anticipated expiration: 1949-01-12

Description

Jan. 12, 1932. G. M. DEWNG 5 1,841,325

MEANS FOR DRAINING GAS CYLINDERS Filed Dec. 24, 1928 3 Sheets-Sheet 1 2,) 26/ 11v VEN TOR B Y E 7 1 Jan. 12, 1932. s. M. DEMING NEAkS FOR DRAINING GAS CYLINDERS Filed Dec. 4, 1928 3 Sheets-She t ll'lll i lnllla'l I'IIIIII s i NT0R A T QRNEY Patented Jan. 12, 1932 UNITED STATES PATENT OFFICE GEORGE M. DEMING, OF EAST ORANGE, NEW JERSEY, ASSIGNOB TO AIR REDUCTION COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK MEANS FOR DRAINING GAS CYLINDERS Application flled December 24, 1928. Serial No. 328,228.

This invention relates to industrial installations for supplying gas such as acetylene or oxygen from pressure tanks or cylinders and distributing it to stations where it is used under pressure, and is more particularly applicable to the oxygen systems of oXy-fuel-gas installations in welding and cutting shops. a

It is difficult to secure good regulation by means of the pressure regulators when the diminishing cylinder pressures approach the distributing line pressure, and the practice of switching cylinder banks before this stage is reached leaves a considerable amount of oxygen in the cylinders which is not used. The amount of this gas lost to the consumer will vary according to the pressures which are maintained in the distributing line or at the consumption stations. As it may be desired to maintain line pressures as high as 150.

to 200 pounds per square inch and as there must be at least this pressure, and usually a higher pressure, left in each of the cylinders, of which there may be twenty to forty in a bank connected with the same manifold. the loss in unused oxygen may be quite serious.

The object of this invention is to obviate this loss, and to makeit possible to drain a bank of used cylinders into the line, so as to reduce the pressure in such cylinders to or toward atmospheric pressure. complished by applying kinetic energy derived from the outflow from a bank of full cylinders to drain gas from a bank of used cylinders. I find that an ejector connected between two banks of cylinders and the distributing line or system can be caused to drain theused cylinders to a low pressure against the comparatively high back-pressure of the distributing line, provided that the ejector.

be designed to function undera pressure at the entrance of the ejector nozzle high enough above the discharge pressure oi the compressor tube. the rate of discharge of the device then being substantially independent of the discharge pressure. The result is accomplished notwithstanding tactorswhich materially reduce the technical efiiciency of an ejector used in this connection, more especially the very low temperature of the gas This is ac-- heavy temperature gradient and a rapid transfer of heat from the entrained gas stream. The velocity of discharge from the nozzle, in the neighborhood of about 1500 feet per second, causes a considerable loss of energy as the result of impact when the mpidly moving gas stream encounters the slower moving gas stream from the bank of low pressure cylinders. The relative location of the ejector ma? Varied. The ejector might be operate by direct cylinder pressure, but this would have i disadvantages, namely the wide variations in pressure .at the entrance side of the nozzle as very close manufacturing tolerances required the result of falling cylinder pressure, the

for the very small gas passages which would be necessary for cylinder pressures, and the problems of strength and gas tightness.

For these reasons it is very desirable to connect the high and low pressure inlets of the ejector with the lines leading from the pressure reducing regulators which are regularly connected with the manifolds pertaining to the two banks, the outlet of theejector being connected with the distributing line.

In order to avoid excessive pressure being built up in the distributing line when the rate of consumption at the welding or cutting stations is reduced below that for which the ejector is designed, an auxiliary pressure regulator or reducing valve may be interposed between the ejector and said line, which line is provided, as usual. with pressure regulators at the several stations.

The rate of flow through the ejector is a factor as well as the pressures, and the rate of flow is dependent upon the number of stations along the distributing line that may be consuming gas. If the ejector were designed to handle the maximum rate of flow which would ever be required for consumption, it would not operate so well as an ejector at materially lower rates of flow. On the other hand, if it were designed to operate at some minimum flow, it would be incapable of supplying gas to the distributing line at a high rate of flow when called upon to do so. These difliculties may be reconciled by proper proportioning of the passages if the length of time .required for draining is not important. Preferably, however, I design the ejector proper to handle medium or low rates of flow and provide a by-pass for conducting some of the high-pressure gas around the ejector, so as to keep the distributing line adequately supplied for larger consumptions and to prevent the discharge pressure of the ejector from falling below a desired limit. A

normally closed valve in this by-pass, which opens more or less against spring-pressure in accordance with and in response to varying reduced pressures in the distributing line, automatically adjusts this secondary or bypassed flow.

With all or most of the consuming stations closed, and with the bank of used cylinders in communication with the low pressure gas inlet of the ejector, gas from the banks of filled cylinders would be forced around from these cylinders into the used cylinders. 'To prevent that from happening, the invention includes a rearwardly closing check valve in the passage leading to the low pressure inlet of the ejector.

Finally, in order to avoid draining the used cylinders down to too low apressure, a valve is provided which shuts off the supply of low pressure gas automatically when a predeter mined lowering of pressure has been attained. Preferably, this valve is arranged to be actuated by atmospheric pressure, so as, to close whenever the pressure in apassage leading to the induction space of the ejector falls below the pressure of the atmosphere.

-In-the accompanying drawings, forming a part hereof: Fig. l'is a schematic plan View of an embodiment of the invention;

Fig. 2 is a longitudinal section through the automatic flow-switching device indicated in Fig. 5 is an axialsect-ion through the manual flow-reversing cock indicated in Fig. 4;",

Fig. 6 is an axial sectiontaken at right angles to 5;

Fig. 7is a cross-section on the line-77 of Fig 5; and

Fig. 8 is a longitudinal section through a a flow-reversing device:

. reversible ejector which may be-used without The drawings show two banks of oxvgen cylinders 2, the banks being designated. re-- spectively, as A and B. The cylinders of each bank are detachably connected in the usual way with a

manifold

3 or 3*,connected with the outlet end of which is a customary pressure regulator or adjustable reducing valve 4 or P, a manual shut-off

valve

5 or 5? being interposed between the regulator and the manifold.

The bank B may be considered to be a bank of used cylinders from which gas is being drained, and the bank A a bank of full cylinders. WVhen the cylinders of bank B have been sufficiently drained, the valve 5 is closed and they are replaced by fresh cylinders. hen, as the result of consumption, the pressure in the cylinders of bank A falls too low for service, the bank B is turned on and the cylinders of bank A are drained to or about atmospheric pressure,

after which they in turn are replaced by fresh cylinders, and so on.

In Figs. 1 to 3,

conduits

6 and 6 leading from the

pressure regulators

4 and 4* are connected with

inlets

7 and 7 opening through opposite sides of the casing 8 of an automatic switching valve, referred to herein by the same number as the casing, which automatically reverses the two flows of gas to an ejector 9. The said casing also .has two

outlets

10 and 10 at opposite sides, and a third outlet 11, which may be disposed centrally at one end.

The interior of the casing 8 is divided by a wall 12

intotwo chambers

13 and 13, the one provided with the inlet 7 and outlet 10 and the other with the inlet 7 and outlet 10*. There is an opening 14 through the middle of the wall 12 and openings 15 in another portionof the wall place both chambers in communication with the outlet 11.

In each chamber there is a

flexible diaphragm

16 or 16, held tightly around its edges, these diaphragms being adapted to seat at their central portions, after the manner of a valve, against two sets of outer and

inner nozzle lips

17 and 17 projecting from the wall 12. Diaphragm plates 18 and 18 are suitably secured to the outer sides of the diaphragm, as by means of screw studs and nuts 19, which may also secure

valve portions

20 and 20*, which are adapted to coact with

nozzle lips

21 and 21 projecting inward from the walls of the casing around the

outlets

10 and 10.

1, The screw studs19 project from opposite endsof a barrel 22 which is guided in the opening 14. Thus, the diaphragms are tied together at the middle to move in unison.

' Ports 23 and 23 are formed through the diaphragms and diaphragm plates, their inner ends opening between the concentric nozzle lips 16 and'16. When the pressure in chamber 13, at the outer side of diaphragm 16, is higher than the pressure in chamber 13 at the outer side of the diaphragm 16", which is the condition illustrated, the diaphragm 16 is pressed inward against the concentric nozzle lips 17 to close ofi' C0111- munication from the chamber 13 to the outlet 11 by way of the ports 23, and the valve element 20 is displaced away from the nozzle lip 21, permitting the higher pressure gas, which enters at 7, to

out at 10. At the other side of the wall 12,

the diaphragm 16 is held outward away from the nozzle lips 17 and its valve element 20 is pressed against the nozzle lip 21*. Consequently, the low pressure gas which enters at 7 a passes through the ports 23 to the other side of this diaphragm, and flows out through the outlet 11.

When the pressure conditions are reversed, the diaphragms areautomatically shifted, to

reverse the flow conditions.

The

outlets

10 and 10 are connected with branches of a conduit 24 which leads to the body of the ejector 9, where it is connected with the entrance to the nozzle 25 of the ejector. In the particular construction shown, the end of the conduit 24 is connectedwith a chamber 26, which in turn is connected by passages 27 with a chamber 28 in a nozzle plug, .the flaring passage 29 of the nozzle extending from this chamber.

The outlet 11 of the switching device is connected with an end of a conduit 30, the opposite end of which is connected with a chamber 31 in the body of the ejector. This chamber contains a rearwardly closing check valve 32. The function of this valve, as already explained, is to prevent high pressure gas from the nozzle 25 forcing its way around into the cylinders which are to be drained,

in event that the, outflow from the ejector should be cut off by reason of all the consumption valves connected with the distributing line 33 being closed, or in event that the con- 0 suinption should fall below theoutflow capacity of the ejector.

This valve may be of the bal-ltype urged by a light spring 34: to a seat 35 at the end of the conduit 30. This spring yields readily to the pressure of;v the low pressure gas entering this chamber, though if desired a stronger spring could be employed for the purpose of -limiting the extent to which the pressure in cylinders undergoing draining may be reduced.

A passage 36 extends from the chamber 3] to a valve chamber 37, and from this chamber another passage 38 leads to the induction space 39 around the ejector nozzle.

valve chamber 37 contains a diaphragm 40,

constituting one form of automatic valve for closing off the bank of empty cylinders from the ejector when the pressure in those cylinders has been reduced to a desired point. It is preferable to interrupt the draining when the pressure has been brought down to or approximately to atmospheric pressure, that is to say zero' gauge pressure, and it would usually be undesirable to exhaust gas from the used cylinders beyond that point.

ZISS

sure in this space will be below the atmos- The the pressure .in the part of the system in which the valve is placed falls slightly below atmospheric pressure the valve will close, cuttingv of! further drainage from the used cylinders.

It is not necessary that either this automatic limiting valve or the back-flow cut-off valve 32 be associated with the ejector itself, since they may be placed elsewhere in theconnections. In the case of the valve 40, however, there is an advantage in placing such a valve comparatively close to the induction space 39 of the ejector. By proper design of the ejector so that the working prespheric level, the emptying of the low pressure cylinders is hastened, and, as the pressure of the gas in the passages 36 and 38 falls, the valve will be caused to close against the nozzle lip 41 at or slightly before the time when the ca diminishing pressure in these cylinders reaches that of the atmosphere.

The combining tube of the ejector is represented by the convergent portion 42 of the passage in line with the nozzle, and the compressor of the injector includes the gradually widening prolongation 43 of this passage.

The compressor delivers into a passage 44 which is connected by a conduit 45 with the distributing line 33 previously referred to.

This line is representative of a distributing system, ,which may comprise any number of connected lines. A number of station pressure regulators are indicated at 46, the outlets of these regulators being connected with the torches or other consumption devices. a As heretofore explained, it is of considerable advantage to employ an ejector which is adapted to pass less than the maximum flow which-may be required to supply the dis- 11p tributing line or system at full consumption.

In order that heavier flows may be passed to the distributing system, a by-pas's and automatic by-pass valve are employed for conducting high pressure gas past the ejector .15

proper when the consumption requirement becomes greater than the capacity of the ejector. This by-pass is not required to be in the body of the ejector, but it is desirable so to arrange it. As shown, a passage 120 47 is drilled in this body from the nozzle entrance chamber 26 to a valve chamber 48,

the latter communicating with a passage or space 49 which communicates in turn with the junction between the compressor 43 and the passage 44'. A ball valve'50 in the chamber 48 is pressed rearward by a spring 51 against a seat 52, the force of this spring being sufficient to keep the valve closed at low or moderate rates of consumption of gas, but

to permit the valve to open to varying eX- tents under heavier demands so as tosupply the amount of additional flow that may be needed.

The operation will be briefly reviewed, Assume that the cylinders of bank A are full of compressed oxygen, or that they contain adequate pressure for operating the ejector and supplying the distributing line, that the cylinders of bank B have been used until they no longer have sufiicient pressure to serve the distributing line but that they still contain oxygen under pressure above atmospheric which it is desired to recover, that the manifolds of the two banks are connected with the switching, device 8, the latter with the ejector and the ejector with the line, as shown, and that the adjustment of the regulating screw of the regulator 4 is such that the as from the low'pressure cylinders will be a le to flow freely through this regulator. The, switching device 8 causes the gas from the manifold 3 'ofthe high pressure bank to pass to the nozzle of the ejector, while gas from the manifold 3 of the low pressure bank of cylinders finds its way-to the induction space of the ejector. The high velocity gas stream delivered from the ejector nozzle draws in or entrains the low pressure gas, pressure is recovered in the compressor and the combined stream overcomes the pressure in the distributing line as long as a suflicient number of the consumption devices are in operation. If the consumption should cease or should fall too low, the back-pressure cutoff 32 will automatically close. When the cylinders of bank B have been drained down to the desired point, the limiting valve 40 closes automatically, preventing the pressure in these cylinders from being exhausted below atmospheric pressure, or below such other point as may be desired. If while the ejector is acting as an ejector, or while it is acting merely as a conduit after the draining of the cylinders of bank B has been completed, the consumption should increase beyond the capacity of the ejector to pass the requisite flow, the by-pa'ss valve 50 will open automatically to ermit additional flow.

Figs. 4 to illustrate a manualswitch cock 53 used in, place of the automatic switching device 8 forreversing the flows from thetwo

manifolds

3 ,and 3 with respect to the nozzle and induction spaces of the ejector 9.

In this case, the

conduits

6 and 6 leadingfrom the .pressure regulators 4' and 4 are branched in the casin of the turn-cock, so that in one position 0 the latter these con-.

. duits will communicate, respectively, with

passages

54 and 55 in the turn plug, these passages then communicating, respectively, with the

conduits

24 and 30 leading to the ejector, whereas in another position of the plug, these passages then communicating in turn with the

passages

30 and 24, respectively, the passages 30 and 24: being likewise branched in the casing of the cock.

Fig. 8 illustrates the fact that a reversible ejector may be employed, in which event a separate manual or automatic switching device would not be used. Such an ejector is one which is properly designed so that the high velocity stream may be delivered either through the nozzle or around the nozzle and will entrain the stream supplied from the low pressure source whether this stream enters around the nozzle, in the first case, or through the nozzle, in the second case- In such an ejector the

chambers

26 and 31 serve alternately as entrance chambers for low pressure gas, and consequently each of them is provided with a back-pressure cut-off valve 32. Each of these chambers likewise serves alternately for admission of high pressure gas, and consequently each has a" by-pass channel 47 leading therefrom to a valve chamber 48 containingone of the by-pass valves 50, both of these valve chambers communicating with the space 49.

While a reversible ejector eliminates the necessity for a switching device, or for interchanging connections if a switching device is not used, it presents a disadvantage for manufacturing purposes in that the tolerances for error in the annular space around the nozzle have to be very close in this type of ejector. Furthermore, this space or passage would have to be so small that the time of draining would be prolonged. For these reasons it is considered preferable to employ a non-reversible ejector in connection with means between the ejector and the banks of cylinders for switching the flows.

It will be understood that the invention is not limited to the forms and arrangements shown and that various other modifications are within the scope of the appended claims.

I claim:

1. The combination with a' plurality of separate banks of portable compressed gas cylinders, and a common distributing system to -be supplied, of ej ector means between said banks and said distributing system to drain into the distributing system gas re maining in one bank of cylinders by kinetic eneilzgy derived from the outflow of another ban 2. The combination with the manifolds and therewith connected pressure regulators of a plurality of separate banks of portable compressed gascylinders, and a common distributing system to be supplied, of an ejector connected between said pressure regulators and said distributing system to drain into the distributing system gas remaining in one bank of cylinders by the kinetic energy derived from the outflow passed by the'regulator of anotherbank.

fis

matically by-passing some of the high-pressure gas to supply the distributing system with gas in excess of the capacity of the ejector proper.

4. The combination with the manifolds and therewith connected pressure regulators of a plurality of separate banks of portable compressed gas cylinders, and a common distributing system to be supplied, of an ejector,

connected between said pressure regulators and said distributing system to drain into the distributing system gas remaining in one bank of cylinders by the kinetic energy derived from the outflow passed by the regulator of another bank, means providing a bypass from the high pressure side of the ejector to the discharge side thereof, and a normally-closed valve in said by-pass adapted to open against spring-pressure in response to reduction in gas pressure at the discharge side.

5. The combination with the manifolds and therewith-connected pressure regulators of a plurality of separate banks of portable compressed gas cylinders, and acommon dis tributing system to be supplied, of an ejector connected between said pressure regulators and said distributing system to drain into the distributing system gas remaining in one bank of cylinders by the kinetic energy derived from the outflow passed by the regulator of another bank, and means for automatically closing the passage for low pressure gas to said ejector when the pressure of said gas falls to a predetermined low value.

6. The combination with the manifolds and therewith connected pressure regulators of a plurality of separate banks of portable compressed gas cylinders, and a common distributing system to be supplied, of an ejector connected between said pressure regulators and said distributing system to drain into the distributing system gas remaining in one bank of cylinders by the kinetic energy derived from the outflow passed by the regulator of another bank, and means for automatically closing the passage for low pressure gas to said ejector when the pressure of said gas falls to a predetermined low value, said means comprising a valve actuated by atmospheric pressure.

7. The combination with the manifolds and therewith connected pressure regulators of apluralit-y of separate banks ofportable compressed gas cylinders, and a common distributing system to be supplied, of an e ector connected between said pressure regulators and saiddistributing system to drain into the distributing system gas remaining in one bank of cylinders by the kinetic energy derived from the outflow passed by the regulator of another bank, and a rearwardly closing back-pressure shut-off valve in the low pressure passage to said ejector.

8, The combination with the manifolds and therewith connected pressure regulators of a plurality of separate banks of portable compressed gas cylinders, and a common distributing system to be supplied, of an ejector connected between said pressure regulators and said distributing system to drain into the distributing system gas remaining in one bank of cylinders by the'kinetic energy derived from the outflow passed by the regulator of another bank, and means for reversing the flows from said regulators to the high and low pressure inlets to the ejector without change in connections.

9. The combination with the manifolds therewith connected pressure regulators of a plurality of separate banks of portable compressed gas cylinders, and a common distributing system to be supplied, of an ejector connected between said pressure regulators and said distributing system to drain into the distributing system gas remaining in one bank of cylinders by the kinetic energy derived from the outflow passed by the regulator of another bank, and means for automatically reversing the flows from said regulators to the high and low pressure inlets of the ejector.

10. The combination with the manifolds and therewith connected pressure regulators of a plurality of separate banks of portable compressed gas cylinders, and a common distributing line with pressure regulators connected therewith at consumption stations, of

an ejector connected between the first-mentioned regulators and the distributing line to drain into the distributing line gas remaining in one bank of cylinders by the kinetic energy derived from the outflow passed by the regulator of another bank, and an auxiliary pressure regulator between said ejector and said distributing line.

GEORGE M. DEMING.