US2572449A - Condensation pump - Google Patents

Description

1951 R. E. CORTRIGHT CONDENSATION PUMP Original Filed Jan. 16, 1946 FIG. 2

ROBE-R r 500/? TR/GHT INVENTOR.

BY 4 ff;

h). 5511mm ATTORNEYS Patented Oct. 23, 1951 CONDENSATION PUlVIP Robert E.- Oortright, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Original application January 16, 1946, Serial No. 641,479. Divided and this application July 18,

1950, Serial No. 174,442

Claims.

My invention relates to an improvement in high vacuum concentric fractionating pumps and in particular to high vacuum pumps in which there are a multiplicity of concentric fractionating columns or boilers.

Such high vacuum pumps are described in and are well known in the prior art as vertical concentric fractionating condensation pumps; see, for instance, patents Hickman U. S. No. 2,211,329,

Hickman. U. S. No. 2,080,421, and Embree U. S.

No. 2 150,676. In such condensation pumps an organic working fluid is heated in a series of concentric boiler compartments and the vapors therefrom are delivered to the jet nozzles through which they then issue, entraining gases from the chamber to be evacuated and condensing on the inside walls of the pump casing and flowing down such walls. The concentric arrangement of the boiler compartments is such that the lowest vapor pressure components of the pump or working fluid, which cannot be vaporized without decomposition, are delivered to a jet nozzle at least once removed from the highest vacuum jet nozzle so that the next lowest vapor pressure components which can be vaporized without appreciable decomposition are deivered to the highest vacuum jet. It has been found, however, that it is difficult to prevent the uncontrolled seepage of the working fluid from one boiler into another and thereby impairing the fractionation in the several boilers and reducing the eiflciency of the pumps.

My invention has for its object to provide a means for preventing such uncontrolled seepage or leakage from one boiler into another and thereby to provide more eflicient fractionation in the several boilers by controlling the introduction of the pumping fluid into them. Another object is to'provide improved high vacuum pumping apparatus. Other objectives will appear hereinafter. 1

These and the other objects are accomplished by my invention which includes a vertical concentric fractionating condensation pump as illustrated in Fig. 1 having a plurality of concentric cylinders arranged to channel vapors of pump fluid to the pumping jets, with the outer cylinder terminating at its lower end above the boiler of the pump and extending into an annular gutter on the inner face of the pump casing and the remaining cylinders extending substantially to the bottom of the pump casing, such remaining cylinders, in a preferred embodiment, being provided with means positioned in or around the boiler or boilers thereof for preventing uncontrolled leakage of pump fluid from one boiler to another.

In the following description I have given several of the preferred embodiments of my inven tion, but it is to be understood that. these are set forth for the purpose of illustration and not in limitation thereof.

In the accompanying drawing, wherein like numbers refer to like parts, I have illustrated one of the preferred embodiments of my invention wherein: b

Figure 1 is a vertical section of a high vacuum fractionating pump provided with several concentric boilers or columns embodying the principles of my invention.

Figure 2 is a horizontal section taken on line 2-2 of Fig. 1.

Numeral 2 designates a cylindrical-pump casing, the base of which is closed by an integral plate I2. The top of the casing 2 is provided with a flange 4 which facilitates connection with the system to be evacuated. The upper end, therefore, represents the high vacuum or intake side of the pump. The low vacuum or exhaust side of the pump is .indicated by the conduit 5 which connects with the backing pump (not shown). Numerals I6 and 21 designate approximately concentric cylinders or columns, the base of eachof which is in close and liquid-tight contact with an intermediate base plate 3. Con- A centric cylinders I6 and 21 are each provided with a metal cap or collar, designated respectively as 6 and 6, at their respective bases which fit tightly to the outside of each column. Such cap or collar may, however, be positioned inside the column in a different embodiment of my invention.

As illustrated in Fig. 1, the outer cylinder II, concentric with cylinders I6 and 21, does not extend downwardly to base plate 3 but terminates above the boiler I in an annular gutter or well I5 on the inner face of casing 2. The relative lengths of cylinders I6 and 21 and cylinder II are arranged so that cylinders I6 and 2'! rest on base plate 3 and, through members 28, 28, support cylinder II with its lower end out of contact with the bottom of gutter I5 so as to allow flow of pump fluid around the lower end of cylinder II. Spacers I1, I! on cylinder II ensure proper lateral alignment of the lower end of cylinder II out of contact with the walls of gutter I5.

Numerals I3, I4, 2| and 23 designate annular jet lips integral with the periphery of the columns II, I6 and. 21, respectively, so as to form high,

and are condensed on the wall of casing 2. condensed liquid flows back into boiler'compart- ,taining a liquid seal.

intermediate and low vacuum jet nozzles. Numerals 22, 24, 2B and 34 designate openings through which vapors issue into the jet nozzles from the spaces between the concentric columns. Numeral I designates the annular boiler defined by column !6. andthe inside of the pump casing 2 and which supplies working Vapor to jet nozzles I3 and I4. Numeral 8 designates an annue lar boiler which supplies working vapor to jet nozzle 2|. Numeral 9 designates an annular boiler which supplies working vaporlto jet noz-.- zle 23 Numeral l designates anelectrical h'atin'g'el'ement so positioned in the base of the pump casing between the plate l2 forming the bottom thereof and plate 3 as to heat boiler compartments 1, 8 and 9. Numeral 25 designates copper coils in which water is circulated to cool thecas- 1iqng 2 and assist condensation of the working uid.

'In'operating the apparatus illustr'atedih Fi'g. 1 an organic pump fluid is introduced'i'nto the pump. Flange 4 is connected tolthe system to be evacuated and conduit 5 is connected to a backing'pump in the usual manner.

The base plate 3 is'then heated by the electrical heatingelement l0. Vapor produced in boiler section 1 rises in ,the annular space between column l I and column I6 and passesthrough holes 22 and and issues'from jet nozzles l3 and M. The jet entrains ;acts as a liquid seal and serves-to prevent streaming of pump fluid vapors-into the space between cylinder II and casing 2 except from theHjet i nozzles. Pump fluid vapors issuing from jet nozzles I3, I 4, 2| and 23 condense on casing 2 and flow downwardly into gutter [5. The condensed pump vapors continually overflow gutter. l5 and arrive back'into the boiler compartment 1 from which they were derived; The unvaporized liquid in compartment 1 flowsina circular path to opening l8 and into boiler compartment 8. When the liquid arrives in boiler compartmentB it has traveled in a tortuous-path through boiler 1' and has, therefore, been deprived, of high vapor pressure constituents before passing through opening 18.

In boiler compartment 8 the next lowest below the high vapor pressure constituents are vaporized and pass upwards between concentric columns l6 and 21. These vapors issue through openings 26 and pass out through jetnozzle 2| The ment 7 through gutter l5 where it aids in main- The pumpfiuid which is not vaporized in boiler compartment 8 passes in a circular or tortuous path to a passage l9 and into boiler compartment 9.. Here the'lowest vapor pressure, components are vaporized and rise and issue throughopening 34 and pass from jet nozzle 23. Since this jet is the highestvacuum jet, it is desirable that it be supplied with the best portionof the pump fluidvapo'rs, The vapors issuing from jet 23 are condensed on ,the

walls of casing 2 and fiowvby gravity, back .into

boiler 1 through gutter l5 in like manner.

It is apparent that efficient fractionation of the pumpfluidtakes place in the operationof 4 this apparatus. The pump fluid ls segregated into components of gradually increasing vapor pressure as in prior constructions but the lowest vapor pressure component is segregated and is not permitted to be vaporized and delivered to the highest vacuumjet. Theh'arm'fful efiects of its decomposition products are thereby avoided.

The feature of causing the pump fluid to pass in fractionating pumps of all types. If the pump fluidis-permitted'to flow too quickly from one eompartment to another it is not efficiently stripjet nozzle means, and a vapor-conducting cylinped of its lighterconstituents and these will be vaporized at apoint where they may adversely affect the pumping action. By causing liquid to lpass 'inrattcrtuous path, removal of all volatile-constituents before it reaches the next boiler compartment is assured.

In the preferred embodiment of the invention as shown in Fig. 1, the shortened'outer cylinder ll and-gutter l5 combine with'condensed pump fluid to afford a liquid'sealpreventing undesirable escape of pump fluid'vapors from the boiler '1 except between cylinders ll and l5. This arrangement allows-free flow of condensed'pumping fluid back to'the boilers for revaporization and permits utilization of the entire base of the pump as boiler space. The cylinder-nozzle assembly isreadily removed'to permit cleaning of the pumpand the pump is readily reassembled for use.

Uncontrolled seepage ofi such returned 'pump fluid into boiler designated numeral 9 is prevented by the welding to the bottom of such boiler and the adjacent boiler compartment 8 of metal caps or collars designated numeral 6 which'have rims the diameter of "whichis closely fitted to either the outside or theinsidediameter of the base of the concentric fractionatirig columns. Entrance openings extend through the columns andjthe caps as designated by numerals 1-8 and E9 on opposite sides ofthe'c'olum'ns. Thus not only is seepage prevented by the base of each column being individually and completely sealed off, but my invention also accomplishes a complete circulation in the heating chambers. Due to the thin construction of the sealing cap, the heat remains uniform, if this is desired;

This application is adivision of my copending application Serial No. 6411479fild January '16, 1946 which matured into Patent No. 2,521,345

dated September 5, 1 950.

der communicating with said jet nozzle means and extending downwardly from said jet nozzle means. the lower end of said vapor-conducting cylinder being disposed in; said gutter whereby pumping fluid condensing on said casing collects ,in said gutter'and forms a liquid'seal'around the 'said casing and. extending upwardlyfrom said boiler means, jet nozzle means communicating with the upper ends of sa'idpylinders, an annular gutter around the inner circumference of said casing between said boiler means and said jet nozzle means, the outer cylinder of said plurality of concentrically arranged cylinder being disposed with its lower end in said gutter and being arranged to permit flow of pump fluid into and out of said gutter around said lower end of said outer cylinder.

3. A high vacuum condensation pump comprising a pump casing, boiler means in the lower end of said casing, jet nozzle means above said boiler means, an annular gutter around the inner circumference of said casing above said boiler means and below said jet nozzle means, and a vapor-conducting cylinder communicating with said jet nozzle means and extending downwardly into said gutter, said cylinder having an outer diameter substantially less than the inner diameter of said casing, the diameter of the lower end of said cylinder being substantially greater than the inner diameter of said annular gutter whereby the lower end of said cylinder is out of sealing relation with said casing and said gutter.

4. A high vacuum condensation pump comprising a pump casing, boiler means in a lower zone of said casing, jet nozzle means in a higher zone of said casing, an annular gutter around the inner circumference of said casing between said boiler means and said jet nozzle means, a plurality of concentrically arranged vapor-conducting .cylinders disposed in said casing and beingarranged for conducting pump fluid vapors from said boiler means to said jet nozzle means,

the outer cylinder of said plurality of concentrically arranged cylinders being disposed with the lower end of said outer cylinder in said gutter, the diameter of said lower end being less than the outer diameter of said gutter and greater than the inner diameter of said gutter, said outer 4 cylinder being supported with its lower edge out of contact with the bottom of said gutter, said gutter being arranged to collect condensed pump fluid flowing down the inner face of said casingwhereby pump fluid thus collected forms a liquid seal around said lower end of said outer cylinder.

5. A high vacuum condensation pump comprising a pump casing, boiler means at the lower end of said casing, jet nozzle means in a higher zone of said casing, a plurality of concentrically arranged vapor-conducting cylinders in said casing and being arranged for conducting vapors of pump fluid from said boil-er means to said jet nozzle means, an annular gutter around the inner circumference of said casing above said boiler means and below said jet nozzle means, said gutter being arranged to collect condensed pump fluid flowing down said casing, the outer cylinder of said plurality of concentrically arranged cylinders being disposed with the lower end of said outer cylinder in said gutter, spacer means arranged to maintain said outer cylinder with said lower end of said outer cylinder out of contact with said casing and said gutter, the inner cylinders of said plurality of concentrically arranged cylinders extending to the bottom of said casing, said outer cylinder being supported by at least one of said inner cylinders with the lower end of said outer cylinder out of contact with the bottom of said gutter.

ROBERT E. CORTRIGHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,080,421 Hickman -.May 18, 1937 2,150,676 Ernbree Mar. 14, 1939 2,211,329 Hickman Aug. 13, 1940 2,521,345 Cortright Sept. 5, 1950

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