US2183639A - Eduction device - Google Patents

Description

EDUCTION DEVICE Filed Jan. 6, 1937 w m an OD TR mm MN N H O J 3 G F D m mm Q F m m w w i WA i BY ERIC E SOMMER ATTORNEY Patented Dec. 19, 1939 2,183,639

UNITED STATES PATENT OFFlCE EDUCTION DEVICE John N. Burclick and Eric E. Sommer, Buffalo,

N. Y., assignors to Carbide and Carbon Chemicals Corporation, a corporation of New York Application January 6, 1937, Serial No. 119,285

11 Claims. (01. 62l) The invention pertains to eduction device when such an eductor was provided with pluand more particularly to an eductor for removrality of openings, of which one was the vapor ing a substantially uniform composition of a phase at least during a portion of the discharge, compressed mixture of at least partially liquefied a slow rate or" discharge then discharged only ;;gases of difierent vapor tensions from a 0011- gas and this also left an inflammable residue. 5

' tainer in which they are confined under pressure. We have found however that the inflammability An example of such a composition or mixture of the discharged gases or mixture be practi is one containing carbon dioxide and ethylene cally or entirely eliminated by discharging the oxide in the approximate proportion of parts mixture through a jacketed eductcr tube having 10,;of the former to 1 part of the latter. This :naopenings of suitable size and location in both 10- terial is handled in conventional pressure vesthe mile tube and the outer jacket. sels, for example cylinders such as those used One embodiment of the invention shown by for the transportation of oxygen, and under the above-mentioned drawing may comprise an normal conditions the cylinders are approxieductor secured in the inner end of an 15,,mately half full of the liquid phase of the through a conventional valve B that closes an ture which is under about 690 pounds pressure. opening in the upper end of a conventional pres- Due to the widely difierent vapor tensions of the sure vessel or cylinder C. The cylinder C in two components the vapor phase is largely carhe of the type usually employed. c bon dioxide while the liquid phase is a mixture oxygen under high pressure and the valve B may 2 of the two components having a higher ethylene be removably secured in the upper end or neck oxide content than the average of the entire thereof by suitable interfitting threads in a concontent of the cylinder. ventional manner.

The mixture under discussion is used as a The eductor A may be disposed vertically withfumigant and under some conditions one cylinder in the cylinder C and extend from the valve 13 may be used for several fumigation operations. downward substantially to the bottom, and the 25 To be most effective and free from fire hazard upper end of the eductor may be secured to the the proportion of the mixture used for each valve B in a suitable manner. For example, a fumigation should be substantially that of the suitable portion ill of the upper end of the tubular entire content of the cylinder. Therefore, one eductoi A may be disposed in a suitable recess 12 of the objects or the invention to provide an in the lower end of the valve B and the joint 30 eductor tube that will remove a substantially between the eductor and the valve may be closed uniform proportion of a compressed mixture of and further secured by suitable means such as a plurality of partially liquefied gases having solder. Thus the upper end of the fluid passage different vapor tensions from a cylinder in which through the eductor may be connected with the it is contained. Other aims, objects, and novel inner end of the outlet passage through the 35 features may be obtained from the following valve B. description and the accompanying drawing in This improved educt'or may comprise an inner which: tube M which may be surrounded by jacke Fig. 1 is a longitudinal section through a cylinor outer tube 5%. These concentric tubes may 40 der having an outlet valve and an eductor atextend from the bottom of the cylinder 0 to 40 tached thereto. the lower portion of the valve B, but since it Fig. 2 is a View in partial section of the eductor has been found desirable to bend the eductor tube and part of the valve shown in Fig. l, and so that the lower end will be disposed in the Fig. 3 is a sectional view of the lower part of lowermost portion of the cylinder, which is near 5 the eductor and a fiat bottomed cylinder showthe side wall, the upper portion of the eductor ing the action of the mixture during withdrawal. may comprise a single tube l8 which is more In an eductor, such as those employed hereeasily bent. Therefore, the upper portion of the tofore, the lower end was closed and the side eductor may consist of a single tube i8 while the 'D V B With Suitable opsningS through Which lower portion may consist of concentric tubes h contents f the Cylinder W i ha ed. l4 and Is. The upper tube l8 may be secured 50; When such a tube was provided with a single to the lower end of the valve B in the manner opening near the bottom, liquid only was realready described. The inner tube l4 may be moved with the result that the residual liquid secured within the lower end of the tube 18 by became richer in ethylene oxide until an ina fluid-tight joint, and the outer tube or jacket flammable mixturemight be discharged.v Also,, 15 may be secured to the outside of the. lower: 55;

tom of the container.

end of tube l8 by a similar joint. In the construction shown, the upper end of tube i6 is enlarged slightly so that it will fit over the lower end of tube l8 and the joints between the upper tube l8 and the lower tubes Id and It may be further sealed or secured by suitable means such as a solder of which silver solder is preferred. The lower ends of the tubes l4 and it may be closed by suitable means such as a plug 28 secured in the lower end of the inner tube M and a ring 22 secured in the annular opening between the lower ends of the tubes it and I6. These closures numbers Zll and 22 may also be secured in place by any suitable means such as a solder.

The length of the upper tube l3 with respect to the lower tubes I l and It may vary according to the character of the mixture being discharged and the location of the tubes i l and it. However, for the mixture described hereinbefore the length of the tubes M and it may be somewhat greater than half the interior height of the cylinder. Although the conducting capacity or cross-sectional area of the interior of the eductor may vary according to various conditions of usage, excellent :results have been obtained from a tube Hi having an inner chamber 23 with a capacity somewhat greater than the capacity of the outlet through the valve B, and an outer tube or jacket I6 of such a size that the capacity of the annular area or outer chamber 26 between the tubes l4 and I6 is somewhat greater or about twice the capacity of the chamber 23.

The fluid passage through the inner tube l4 may be provided with an inlet adjacent the bot- This inlet may comprise two openings which may be located in opposite sides of the tube it closely adjacent to bottom wall 20 and have a combined area or capacity substantially equal to the interior area or capacity of the tube i l. To withdraw a substantially uniform mixture of the contained gases at normal rates of discharge the outer tube or jacket I6 may be provided with a plurality of openings in the outer wall thereof. These openings 25 may be spaced vertically one above the other, with the lowermost hole or opening as near the bottom wall 22 as commercially practicable, and the uppermost openings somewhat more than half the distance between the lower end of the eductor tube A and the lower end of the valve B.

The openings 25 may have a vertical spacing that is substantially logarithmic with the distance between the openings increasing from the bottom upwards. Although the number of openings 25 may vary according to various conditions of usage, excellent results have been attained by employing seven openings, all in the liquid phase of the mixture when the cylinder is fully charged, and of such a size that their combined area or capacity is somewhat less than the interior area or capacity of the tube l4, so that under conditions of normal discharge there is a substantial pressure drop between the inside and outside of tube It.

The location of the openings 25 may be such that changes in the liquid and vapor phase composition due to changes in liquid and vapor phase volume, as the cylinder is discharged, are compensated for by more of the openings appearing in the vapor phase and thus admitting more vapor phase into the discharge or central tube. The combined area of the openings 24 in the inner tube I4 may be sufiiciently large to have a small enough pressure drop to drain either partly or completely the residue of liquid present in the annular chamber 26 between the inner and outer tubes I4 and I6. At the same time the combined area of the inlets or openings 25 in the jacket or outer tube It may be sufiiciently'small to have a large enough pressure drop so that the liquid entering through them cannot completely fill the chamber 26. In consequence of this high pressure drop as soon as an opening is uncovered or opened to the vapor phase the vapor phase is forced through it and mixed with the liquid phase, so that the composition of the discharge remains substantially uniform.

Fig. 3 shows the condition in the eductor A during normal rates of discharge. Here, it will be observed, the pressure drop through the openings in the tube It is sufficiently low and the pressure drop through the opening in the tube I4 is sufiiciently high so that very little or no liquid remains in the chamber 26. When a standard cylinder containing approximately 66 pounds of a mixture of substantially 9 per cent ethylene oxide and 90 per cent carbon dioxide is discharged through this improved eductor under unfavorable conditions, such as a relatively high temperature of 100 F. and a relatively slow discharge rate of about 60 minutes to the contents of the cylinder, the maximum ethylene oxide content of the discharged gas is substantially 11.7 per cent. This is below the inflammable limit of 12.3 per cent ethylene oxide in an air mixture and is much lower than the ethylene oxide content of the discharged gas when prior eductor tubes are employed. For example, when using a prior three hole eductor tube under the same condition the maximum ethylene oxide content of the discharged gas would be over 20 per cent. Therefore, it appears that the present invention achieves a decided advance in the accuracy and safety of devices for educting mixtures of liquefied gases from cylinders.

Although a preferred embodiment of this invention is disclosed, it will be clear that this general method of eduction may be applied to apparatus having component parts of different size and in different relative locations without departing from the principle of the invention or sacrificing its advantages.

We claim:

1. Means for educting a uniform mixture of compressed liquefied gases having diiferent vapor tensions from a pressure vessel container, comprising; an eductor within said vessel having an inner and outer chamber formed by a tube enclosed in a concentric jacket member, said jacket member being spaced from said tube to provide in said outer chamber a capacity substantially twice that of said inner chamber; means connecting the inner chamber provided by said tube with the outlet of said vessel; vertically spaced outlet openings in the otherwise impervious wall of said jacket member, and fluid communication between the inner and outer chamber in the lower end of said tube.

2. Means for educting a uniform mixture of compressed liquefied gases having difierent vapor tensions from a pressure vessel container, comprising; an eductor within said vessel having an inner and outer chamber formed by a tube enclosed in a spaced jacket member; means connecting the inner chamber provided by said tube with the outlet of said vessel; inlet openings in the otherwise impervious Wall of said jacket member in vertical logarithmic position with the distance between adjacent openings increasing from the bottom upwardly; and fluid communication between the inner and outer chamber at the lower end of said tube.

3. Means for educting a u rm mixture of compressed liquefied gases having different vapor tensions fl a pressure vessel container, comprising; an educter within said vessel having inn and outer chamber formed by tube enclosed 1 spaced jacket member; means connecting the inner chamber provided by said tube with the outlet of said vessel; vertically spaced inlet openings in the otherwise impervious wall of said jacket member, and fluid communication between the and outer chamber at the lower end of said tube; the construction and arrangement of the being such that the pressure drop through the opening in the lower end of said tube is sufficiently low to drain substantially all of the liquid from the outer chamber during eduction, and the pressure drop through the openings jacket is su ficiently high so he liquid e tering them cannot completely outer chamber during eduction.

An eductor, for einoving a uniform miX ture of two or more liquefied gases from a cylinder in which they are under pressure, comprising; an upper tube having the upper end thereof secured in the outlet of said cylinder; an inner tube ha the upper end thereof se cured in the lower end of u'oper tube, and the lower end thereof adjacent e bottom of said cylinder; an outer tube spaced from and coextensive with said inner tube with the upper end thereof secured around the lower end of said upper tube; means closing lower ends of both said inner tube and said cute tube; said inner tube being provided with an inlet adjacent the lower end thereof; and outer tube being provided with a plurality of vertically spaced inlets.

5. The invention defined by claim 4; in which the cross-sectional area of the said interior tube is somewhat greater than that of said outlet.

6. The invention defined by claim 4 in which the area of the inlet opening in the said inner tube is substantially the same as the cross-sectional area of the interior thereof.

'7. The invention defined by claim a in which the cross-sectional area of the annular openbetween said inner tube and said outer tube is substantially twice the cross-sectional area of A interior of said inner tube.

8. The invention defined by claim l in which the combined area of the inlets in said outer tube is substantially than the area of the inlet in said inner tube.

9. The invention defined by claim 4 in which upper tube is bendable and is capable of g bent to position the lower end of the educ- 1G. The invention defined by claim 4 in which said outer tube is provided with seven inlet openngs with the lowermost substantially at the bottom of said outer tul e, and the spacing between said openings is logarithmic.

11. An eductor, for removin a uniform mixure of two or more liquefied gases from a cylin- E l which they are confined under pressure, .sing; two ch bers connected by a suitl-r e opening adjacent the bottom of said cylinone of chambers being provided with a suitable connection between the upper end thereor" and th outlet of said cylinder, and the other of chambers being provided with a plurality of vertically spaced inlet openings, the spacbetween said openings being logarithmic and upwardly progressing.

JOHN N. BURDICK. ERIC SONHVIER.

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