US2608269A - Oil separator - Google Patents

Description

25, 1952 s. w. BRIGGS 2,608,269

OIL SEPARATOR Filed April 6, 1948 2 SHEETSSI-IEET 1 O I 8 I 6 I I g 7 V t I I I I: I I f*\ Z\ I 1 ll "Q 1 I a I I I I I I I l I I -57 mum '2 2 1 II II I 2 64 Mae III III J :6

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Patented Aug. 26, 1952 UNITED T TES ATENT OFF-ice;j;

I Southwick w. Briggs, Bethesda, Md. ApplicationApril 6, 1948, Serial No. 19,264

This invention relates to apparatus for the removal of entrained liquid from gases and more particularly for the separation ofoil from a refrigerant. I

In the usual refrigeration apparatus the refrigerant is compressed .to a relatively high pressure in a reciprocating; or rotary compressor. The compressed refrigerant in a substantially gaseous condition is then introduced into a condenser Which removes the heat of compression and condenses the refrigerant. The cooled, condensed refrigerant is throttled through an expansion valve which lowers its temperature and isthen introduced into an, evaporator in" which it absorbs heat from. the material to be cooled. The gaseous refrigerant from the evaporator is returned to the compressor torepeat-the cycle.

The heat given up by the material to, be cooled and. the heat introduced into the cycle by the compression of the refrigerant must be removed from the refrigerant in the condenser. In order to, reduce the cost and size of the apparatus, it is highly desirable to have a high rate of heat transfer in the condenser. The refrigerant discharged from the compressor, however, is generally contaminated with entrained oil which coats the heat transfer surfaces in the condenser and reduces its heat. transfer capacity. The presence of a film of oil on the heat transfer surfaces of the condenser may reduce its capaciiw asmuch as25%. o u The oil separators heretofore available have not removed oil from the refrigerant completely enough to prevent the formation of an oil film in the condensers. t has, therefore, been necessary. to over-design the condenser capacity to make allowance forthe low rate of heat transfer. Furthermoraxthe separators'of the prior art have not removed water from, the refrigerant and hydrolysis of the refrigerant withserious corrosion of: the refrigeration equipment has resulted. Moreover, the separators heretofore available generally fail by by-passing refrigerant from the separator directly back to the crankcase of the compressor. It is then not possible to pull the vacuum on the evaporator and the pressure and temperature in theevaporator areincreased.

; It is an object of this invention to remove entrained and dissolved oil from the refrigerant-discharged froma compressor of a refrigerating machine prior to the cooling of thegrefrigerant. V

It is also an object of this invention to remove traces of water from the-refrigerant and oil in a refrigerating machine. 7 I Another object of this inventionis to remove 6 Claims. (01. 183-42) from by-passing theadsorbent block.

impurities such as gums and carbon from the lubricating oil used in the compressor of arefrigerating machine.

A further object of this invention is to provide apparatus for the efficient separation and separate discharging of liquids and gases fromrnixtures thereof.

Still another object of this invention is to provide means for discharging separated oil without passing gaseous refrigerant directly from the separator to the compressor. y 1

With these and other objects in mind which will become apparent in the following detailed description of the invention, this invention tresides in a porousadsorbent block through which the refrigerant dischargedfrorn the compressor must pass before enteringthe -condenser a refrigerating machine. Provision is'made t direct the flow of the refrigerant to aid the :sepa} ration of droplets of liquid from thevgaseousijefrigerant passing through the oil separator. While this invention is described for the separation of lubricating oil from refrigerants, it will be appreciated that the apparatus is efficientfor the separationof liquids from gases generally, and is particularly efficient in the' separatio'ri of liquids from gases which are substantially, insolubleinthe liquids. Y

Inthe drawings:

Figure 1 is a vertical sectional view offthe oil separator of this invention. a I '5 Figure 2 isa schematic flow sheet of refrigerat ing apparatus showing the location of the oil separator inthe apparatus. I

Figure 3 is a detailed sectional view of a float operated valve for discharging the separated Jo'il from the separator; and Figure 4 is a sectional View illustrating, made. tail the closure means to prevent thelrefri era'rft As is best illustrated inFi'gure 2, th e oilisepafrator of this invention .is preferably'iinstalled between the compressor-and "condenser vofaf'refrigerating machine. If;

} Referring to Figure L'the oil'separator of this invention isillustrated in a casing: I, having a base 2 integral therewithand adorned 'coverff3 closing its upper end. Cover 3' is seeurai-gt casing i by means of nuts 6 engaging. studs 5j wh'ich extend upwardly from a flange 6 att'ached'to the .upper end of the casing i. ,A gasket ,1 'on'the upper rim of casingll prevents leakage" betw n the casing and the cover. An inlet Sandanoutlet 9 are provided in,

a a 'i efi Qfli e i e n tim their separator. An outlet tube I communicates with outlet 9 which is substantially centrally located in the cover and extends downwardly therefrom into the casing I. Outlet tube I0 opens downwardly in a container I I secured to its lower end. Container I I occupies substantially the full crosssectional area of the casing and is also open at its lower end I2. The upper end I3 and walls I4 of the container areimperforate, thereby forcing the fluid'passing-through container; II to enter its open lower end I2 and leave through the outlet I0.

Upper end I3 of container II provides a surface on which a helical spring I5 surrounding-the ,andcalso to serve as a valve seat preventing flow outlet tube l0 rests. Helical spring l5 is.in a compressed condition during the operation of the oil separator and bears againstawasher; I.6;-which is slidable along the outer surface of outlet tube I0. Washer I6 engagesia sealing rin II-of compressible material which closes the openings between-the outer surface ofroutlet tube I-II and-a "plate I8 slidable ontube I0.

A porous adsorbent tubular-'block I29 having-a central bore is supported by .plate l8 :which urges the block against the lower surface-of-jthe cover-f the oil separator. Outlet tube l o'passes through the central bore of the adsorbent block I 9. Flow of the refrigerant past 'theends 'of' the "adsorbentblock is preventedby-gaskets Z'I and 22 atthe upper-and lowerends of -the'block, respectively. The central bore 20 of the alumina block :communicates with the inlet 8-of the oil separator.

-'ndsorbentblock I9 is --preferabl-y of-activated aluminabonded with-asuitable inorganic-binder. 5

madsorbent-m'aterialprepared according to'the invention-described in-mycopending application 'filed'onjduly-il; 1948 and having ser'ial -No."37 ,97-l "entitled "Bon'ded Filter Medium in Y which the alumina isbonded with Portland cementis highly satisfactory. Porous, adsorbent --blocks bonded with aluminum phosphate 'or sodium silicate binders arealso-satisfactory. In some instances itim'ay be desirable to provide a porousmass of :activated silica .gel;" however, generally-alumina isjl eferred. since it doesrnot decrepitate-on contact with'water.

A strainer 23 enclosed in a wiremes'hcoverffl is supported .bywires 25 and, 26-in-the,-'iower:end of container II. The*strainer 2'3occupies-the full cross-sectional are'a of container II =to-;prevent :hy passing .of the "refrigerant ,around its sides. As 'mentioned "above, :the container I I is .of large diameter toprovide "a :conduithavinga large cross-sectional area through which-there- "trigerant may passat a very low velocity.

In the preferred form, the;strainer23"consists .offi'a massoffine-copper woo1 which; whilegoftan open 'nature to ;pr,ovide 'alarge free space, also provides an extremely 'lal esurface over which fthe'irefrigerant passes. In certain instances, such as when "the refrigerant iscorrosiveto copper, *it 'will, of course, be'necessary to'provide a strainer of finely divided material -which 1is-resistant to the corrosive ,efiects-aoftherefrigerant. If ammonia is "the refrigerant, steel wool,may housed in 'strainer':23.

"frhelower'endof the casing I-jb'elowthestrainer 23 'servesasa 'well "21 'forthe collection of oil 'separate'dfrom therefrigerant. :A float-operated Valveindicated generallyrby 28, iSiPI'OVidGdY-IJO control the discharge of" the-oi1ifrom thewell' in casing I.

, "Float joperated valve *28 consists -'ofr'abody: 29 drilled and "tapped at 3'0 at "its upper end for .horizontally across the .valvefor thereception of :a valve stem'35. A port 36 passes through the stem in alignment with passage 33 to allow .flow through the valve when the valve stem is in the open position. Conduit 34 is machined to vcloseztolerances to allow stem 35 to rotate therein 'through'theyalve when port 36 does not com- ;municatewith passage 33.

Valve stem 35 may be held in place within the body-29 of the valve by any suitable means. In the form illustrated, a washer 31 engages a gasket =38 in -a recesslin the :body 229 .to fix theposition of the :stem :withimtheibodyrof the :valve. The stem 'isih'eldi'in place byzmeans of :a bolt ?35 engaging a washer 40. Bolt 39 is screwed into the end of stem 35. .A fioatllI is connected by means -of anarm '42 to the stem.35 and rotates'the-stem as thellevel of :the liduidiinzthecwell 21 changes.

Ascreen 43 ishe'ldin place across-the lower -end of the valve body 29.to prevent the entrance of-'any'fluid particles which might accumulate in "the wel1' 2'I. Theopenings'in screen. should "preferably beabout 'the :size of passage J33 to prohibit the entrance :of any particles large enough? to bri'dge across the passage 33 :and preerant-idissolved in the;lubricant; consequently, .as

the compressor "starts to frun,'.largerslugs 'of .oil "are :discharged with fthe refrigerant. rAt fthis time a foam may be :dischargedffromathe. compressor to ='.the separator. :After .the compressor has operated-for :a 'shortwrperiodga dine :mistx-o'f lubricant is generally present in .the refrigerant passing ffrom the ;compressor :to :the -..oil ;sepa- The :velocity of rthecoil-la'den ;irefrigerant.-'entering the inletil :of the oil separator :is mediately .;reduced:.by the large volume of {the central :Ehore L20 of 'the adsorbent .-.block ito =.pre- 'cipitate: alarge: part of the-:oil. Therefrigerant and the oi1 then:pass through -the:porous:adsorb- .ent :block :and .2816 .-:discharged :from. its :outer surface. If .any Tfoam is present, :it is :broken by contact.-.with Lthe surface of .the adsorbent block 31:9. isimilarly, ganytflnemist of liquid ;is deposited and rcoalesces on the 'surfaces.of :the passages "within "the -block :-as the refrigerant follows: anextremely' tor-tuous path therethrough. The liquid phase, which is largely 'oill-butialso containssome refrigerant, sweatssfromithe'outer surface :of the porous "block "I9 and drops from its lower :edge :lin the form of large drops of liquid #which are easily separated from -the gaseous' phase.

If an adsorbent porous'blok of the type-"described hereinbefore is employed,:a=number'of advantages in addition Lto the breaking act the foam andf separation bf -mi'stf-from the gaseous phase are-gained; Arfactivated alumina block, fori example; effectively remove traces ofmoisture from-therefrigerant and oil. The removal'of 'moisture prevents -the hydrolysis of the sir'able that means purities from the lubricant. While only. a-relatively-small portion of the lubricant is dischargedv from the compressor with the' 'refrigerant', the thoroughtreatmentof that portion of the lubricant is suificient to prevent 'the'accumulation of gum and carbon in the crankcase of the compressor.

. The refrigerant dischargedfromthe outer surface of the adsorbent block 19- and the liquid dropping from its lower end pass downwardly in the casing. The large volume of container II results in the gas flowing downwardly at an increased velocity. As the gas passes the lower end I2 of container H, its direction of flow is changed which tends to throw particles of mist from the gas into well 21. The large drops of liquid will, of course, fall readily into the well 21 and accumulate there.

After passing the lower edge l2 of container II, the gaseous phase changes its direction of flow and then passes upwardly at a low velocity through the screen 23. The very large surface and the extremely large number of very small passages in the copper wool within the strainer insures contact of any mist with the surface of the strainer. The last traces of the mist are deposited on the strainer, coalesce, and drop into the well 21. Oil-free refrigerant is discharged from the top of strainer 23 into outlet tube It.

The liquid phase collected in the well 21 will containsome refrigerant. Inthe case of Freon-12, for example, which is completely miscible with lubricating oil, a relatively high concentration of refrigerant may be in the liquid collected in wellZ'l. This refrigerant continually evaporates from the surface of the collected liquid and passes through strainer 23 to the outlet of the separator with the main body of refrigerant.

As the level of the liquid collected in well 2'! rises, float 4| will be lifted and turn stem 35 until port 35 communicates with passage 3. The liquid in well 21 will then enter through the lower'end of the valve body 29 and pass through passage 33 and port 36 to the discharge tube 3|. The liquid discharged through tube 3! and opening 43 is returned to the crankcase of the com.- pressor.

It will be noted that a float operated valve is provided in which the stem and seat of the valve are in sliding contact. In this manner the lodging of a solid particle between the stem and seat is prevented. In separators employing float operated needle valves, for example, a solid particle may lodge in the needle valve. As the be providedtoremovle' imliquidlevel falls, the valve is held open bythe solid particle and eventually gas is returned from the oil'separator to "the crankcase of the-compressor. The compressor is then'not able to pull a vacuum on the evaporator and'the'cap'acity ofthe refrigerating machine is reduced. i I

The refrigerant passing from' outlet fi t'othe condenser is virtually oil-free. Anyoil present will be dissolved by the refrigerant-and will-not collect in the-condenser to form a film on its surfaces. This effective removal of theoil'from the condenser surfaces allows the capacity of the condenser to be increased. "It" is not necessary to make allowances for an oilffilm on the surface of the condenser when they are designed.

The removal of the oil-filmallows reductions of as much as 25% in the area of-the heat co'n-' ducting surface of the conductor with corresponding savings inthe cost of the equipment? While the oil'separator comprising this in vention has been described in detail in "relation to specific forms of the invention, it is to be understood that the concept of this invention-is" not limited to those-specific forms, but is liinited only by the scope of the appended claims. Ii

I claim:

1. Apparatus for the separation ofoil fro'm a refrigerant discharged from the -'compressor --or a refrigerating machine comprising '2, casing having an inlet and an outlet, an outlet tube extending into said casing from the outlet, a tubular bonded adsorbent block having a central bore surrounding said outlet tube, the central bore of the block communicating with the inlet, a container mounted on the outlet tube, a strainer supported in the container, resiliently actuated closure means preventing by-passing of the adsorbent block and directing the refrigerant through said block and strainer to the outlet, and means for discharging the separated oil from the casing.

2. Apparatus for the separation of oil from a refrigerant discharged from the compressor of a refrigerating machine comprising a casing having an inlet and an outlet, an outlet tube extending into said casing from the outlet, a

- tubular bonded adsorbent block having a central bore surrounding said outlet tube, the central bore of the block communiucating with the inlet, a container mounted on the outlet tube, a strainer of cooper wool supported in the container, resiliently actuated closure means preventing by-passing of the adsorbent block and directing the refrigerant through said block and strainer to the outlet, and means for discharging the separated oil from the casing.

3. Apparatus for the separation of oil from a refrigerant discharged from the compressor of a refrigerating machine comprising a casing having an inlet and an outlet, an outlet tube extending into said casing from the outlet, a tubular activated bonded alumina block having a central bore surrounding said outlet tube, the central bore of the block communicating with the inlet, a container mounted on the outlet tube, a strainer supported in the container, resiliently actuated closure means preventing by-passing of the adsorbent block and directing the refrigerant through said block and strainer mass to the outlet, and means for discharging the separated oil from the casing.

4. A separator for the separation of oil entrained in a refrigerant comprising a casing having an inlet and an outlet in the upper end thereof, an outlet tube extending from the outlet nto the eatin and openi g: downmazdlx .there in, an. adsoxbentbleck pQsit-iened, within; he ease na intermediate; the inlet; and theop nin ei the outlet; tubei aiwell. the lower; end of? the e n o; receive the. liquid; cealesee in; he adsexhent. block through which; the. refrigerant: dischar ed; through the porous, block; passes. to the ou l tub and a float. operated, valve t o dis harge liquid. H m. the. well A separator for the, separatiqn of; o i;1 611,- tminedi in; a re ri erant comprising a. easing hey-- in an. inlet and an; outlet; the uppen end; them an; eutlet tubeextendin from; the, eutlet Lute the.- eesing, and. opening downwardly th m 1.11.11 metallie wQol atminerhevihga larg 013.35:- aeetienel; area meuhtedi on. the; lower.- end, of the eutlet. tube. a perpue edsoxbent ble pesitienei within th casin intermediate, the.- inlet: and the openin of he 0ut1et-tuhe, awe11 in,the.-1owex'end: f. he; casin v to.- receive, the. liquid coalesced; in the. adsorbent block; through. which the; refri eran dischargedifrem the hloekpasses, and-afloat Qpemted, valve, to discharge liquid from the well.

6-. Apparatus: for the separation of; liquidifiom. gas in which; the. liquid is, entrained comprising: a casing having an inlet and an outlet in. the upper-portion thereof,v a, porous block mounted within, the easing, means within the casing; for directing the; gas, directly from the inlet; throu h 8:. the 9.011 25: blockwhereby; li -131mlw entrained. in, the gas: is eoeleseedtseie easing; h ng a well; in; lowelt portien fer e l eetinsrliqu d s parated t am.- the. as, a strainer meun ed; wi in e wales,- above th well. wher bycpal sced. r le s. of. liquid. dmn into the welL conduit means direet; ingthe a emer in fr m the p r us block through, the strainer tn th qu e i d means for; disehar -ih th Q leflfQm thewelL SQHILIWICK W. BAIQGS- BEEEBENQES CIIEED The follow-ingreferences are of recoi d in the file of this patent:-

SIAIES BA'ZENTS Number N me D te 1-.H% n-T-51 L M l L 1,280,765. El m-B11 ten-eme- J tv L 1 1,780,156.: H ll; -,.,.-.-.L-.--.V-S- -.,,J=.e. Nevh, ,9119 2,048,993 Clafiey e a1; 4.-Iu1y' .935- 2;2 ,681 Bri gs We July 18 ,1. 2,283,989 Henry 2,285,123,. lfhillipsv 2,341,430 E1s yi-..-,v- F b- 8, .9 ,,4;

FOREIGN PATENTS Number Country 128, 18,

61,073 Germanyh -.--,-.-i June, 3.1228

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