US1789067A - Refrigeration apparatus - Google Patents

Description

Jan. 13, 1931. s. CHADWICK ETAL 1,739,067 REFRIGERATION APPARATUS 7' 7 Sheets- She et 1 TAL 1,789,067

v Jan; 13, 1931. L. s. dHAnwlck ed Aug. 26

19 9 7 Sheets-Sheet 2 Jan. 13, 1931-. s. CHADWICKIZETAL. 7

REFRIGERATION APPARATUS Filed Aug. 26, 1929 7 SheetsSheet 4' Jag. 13, 1931; L. s. cHAb'wlc-k ET AL REFRIGERATION APPARATUS FiLed'Aug. 26, 1929 TSheet-Sheet 6 Jivuqnloos Jain. 13., 1931. L. s. HADWICK ET AL 1 1 9,0 1

' REFRIGERATION APPARATUS Filed Aug. 26. 1929 7 Sheets-Sheet 7 A'ITORN EY 5 Patented Jan. 13, 1931 UNITED STATES PATENT OFFICE LEE S. CHADWICK, OF SHAKER HEIGHTS VILLAGE, -MARC RESEK, OF CLEVELAND HEIGHTS,- AND WILBUIB. G. MIDNIGHT, OF CLEVELAND, OHIO, ASSIGNORS TO PER- FECTION STOVE COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO REFRIGERATIOIT APPARATUS Application fled August 28, 1929. Seriaili'o. 388,406.

This invention relates to improvements in the kind of cooling unit for refrigeration apparatus of the intermittent absorption class that constitutes the subject matter of an application bearing Serial No. 361,579, filed May 9, 1929, by Lee S. Chadwick, one

.of the joint applicants in the present case.

The fundamental object of this and the earlier Chadwick invention is that of stabliizing the temperature of the cold-space of refrigeration apparatus of the class re-' ferred to.

The term cold space, as employed herein, designates either or both the refrigeration compartment-wherein food stufis are placed for preservation, and the freezing chamberwherein water is frozen to produce ice cubes or blocks, or wherein other substances, such as desserts, are chilled or i-ongealed. Obviously, it is essential that the temperature of the freezing chamber be held at or below the freezing point of water if ice is to be preserved, or, below a pointat which'the other substances would soften or :nelt, if their desired consistency is to be maintained.

Both this and the earlier Chadwick inven tion are founded on the fact that, in apparatus of the class referred to, condensation of the refrigerant vapors in the early stage of the heating-condensing period of each cycle of operation occurs in the coldest part of the system and in this connection it should be explained that, prior to the aforesaid Chadwick invention, the coldest part of the system at the time mentioned was. usually, if not always, the evaporator because of the fact that it is subjected to the low temperature of the cold space. The cooling water or solution in the condenser of apparatus of the kind under consideration is practically always of a highertemperature than the cold space, and therefore, with respect to the earlier type of apparatus, until the heating-condensing period .had progressed far enough to cause the pressure within the system to rise sufiiciently high to effect condensation of the refrigerant tion of such vapors would be confined'to the evaporator at the expense of a continuation of the low temperature of the cold space, and of any ice that had been previously frozen therein.

The present and the earlier Chadwick invention provides a unique cooling unit for refrigeration apparatus of the intermittent absorption class .consisting of a receiver, an evaporator, and an auxiliary condenser (so called to distinguish it from the main condenser of the apparatus). The auxiliary condenser includes a receptacle containing a brine, for example, that is frozen during each cooling-absorption period and thus conditioned to condense the refrigerant vapors in the early stage of the subsequent heatingcondensing period and abstract heat therefrom, as will hereinafter more fully appear.

The receiver and the auxiliarycondenser are preferably insulated from the cold space,

while the evaporator is inintimate heat exchanging relation thereto. The parts areso connected for intercommunication that the refrigerant vapors distilled over from the generator-absorber during the early stage of the heating-condensing period of each 0 cle of operation are condensed in the auxiliary condenserand the resultant liquid flows by gravity into the evaporator. Under the coolinginfluence of the auxiliary condenser, this liquid is chilled to such an extent that it has no appreciable warming effect on the atmosphere of the cold space. Therefore it will be seen that, if a brine is used in the auxiliary condenser that has a freezing point somewhat below that of water, the refrigerant liquid will be lowered in temperature to' such a degree that it will not melt ice that has previously, been frozen in the cold space. As the heating condensing period advances, the refrigerant condensate fills the evaporator and continues, to the end of such period, Thereafter lod the condensed and chilled refrigerant in t e evaporator where it remains dormant until the succeeding cooling-absorption pe-. riod. While this represents a long step in the direction of maintaining a uniform temperature inthe cold space, it leaves room for improvement on account of the fact that the temperature of the chilled evaporator gradually rises to or approaches that of the atmosphere in the refrigeration compartment with the result that if sufiicient time was afforded by the heating-condensing period, part of the ice that is present in the tice, the auxiliary condenser is made of sufficient capacity to holdover therequired low temperature of the circulating refrigerant liquid-long enough to avoid melting of ice in the freezing chamber throughout .a heatbeselected for use in the auxiliary condenser 'ing-condensing period.

While we have mentioned ice in particular, and the desire to prevent its melting, it will be understood that the invention is equally applicable to the preserving of other substances in a solid or semi-liquid condition and which, by their nature, may not require the-maintenance of as low a temperature as the freezing point of water. Solutions may according to the conditions that are to be met.

Additional objects of the present invention are the provision of a refrigerator unit of the aforesaid. character that is of sub stantial and durable construction, is relatively simple, is highly efficient, is immune from disorder, and requires no attention.

In the. accompanying drawings, wherein various embodiments of the invention are illustrated, Fig. 1 re resents a sectional front elevation of a re rigeration apparatus embodying the present preferred form of the inventlon; Fig. 2 is a central vertical section through the cooling unit and the adjacent part of the refrigerator cabinet; Fig.3 is a sectional front elevation of said cooling unit, the plane of section being indicated by the Fig. 2, a fra ment of the to of the cabinet being include in full lines, w 'le the insulating jacket that encloses parts of the cooling unit is indicated-by dot-and-dash lines; Fig. 4 is a horizontal section through the cooling unit, substantially on the line 4-4 of Fig. 2; Fig. 5 shows a modified form of theinvention in sectional side elevation; Figs. 6 and 7 are sections on respective lines 6-6 and 7-7 of Fig. 5; and Figs. 8 and 9 refrigerant in the provided with .a'. sump a are fragmentary sectional front and side ele-- vations, respectively,-of another form of the invention.

In Figs. 1 to 4,-the cooling unit is desi nated generally by the reference character It'consists of a receiver a, an auxiliary condenser a',-and an evaporator a. The evap orator is made up of two sections, each in the form of a double wall tube, as best shown in Figs. 3 and 4, the same being closed at its rear end and open at its front so that 'an ice tray (not shown) or the like may be inserted into the freezing chamber that is enclosed by said tube.- The auxiliary condenser 01' consists of a double wall vessel, uite similar, in the present instance, to one o the evaporator sections' The spaces between the inner and outer walls of the tubular sections of the evaporator, and that between the two walls The receptacle just referred to is nearly.

filledwith a suitable brine having a freezing point somewhat lower than the temperature below which it is desired the temperature of the freezing chambers or cold spaces of the evaporator sections shall not go. For example, if ice is to be prevented from melting, a brine is used having a freezing point below that of water, and we find that a 4% sodium hydroxide solution that freezes at about 26 F. is suitable for that purpose. A

space of the auxiliary condenser communicate, through tubes a, with the u per rear ends of the refrigerant spaces 0 the two sections of the evaporator; and the lower forward portions of the refrigeration spaces of the two sections ofthe evaporator c0m-' municate. with each other through a cross tube a. from the central portion of which a tube of is inclined downwardly. and rearwardl to where it joins the enlargedlower end 0 a tubular column a. A tube a leads The upper end portions of the refrigerant downwardly and forwardly from the lower central portion of the refrigerant space of the auxiliary condenser a and joins the..-

lower end of the column a. at a point-di-' ametrically opposite the junction of saidf column and the previously mentioned tube a. The column a communicates at its upper end with the bottom portion of the re-' ceiver a and communication is established between the lower rear end of the receiver and the upper central portionof the auxiliary condenser through a tube a. Between where the tube a and the column a. join the receiver a, the bottom wall of said vessel The top wall of the receiver, aboveth'e region of the sump a3, is formed with a dome a". It will be noted,

from Fi 2, that the receiver is inclined slightly ownwardly from front to rear so that any liquid in said vessel will drain toward the sump a and toward its point of Communication with the auxiliary condenser.

As shown in Fig. 1, our improved cooling unit is situated in the upper portion of the refrigeration compartment or cold space 1 of a cabinet 2 that is constructed of suitably insulated walls. The receiver a and the auxiliary condenser a are enclosed in a jacket 3 of insulating material, while the sections of .the evaporator 01 are exposed to the cold space. A casing 4, located at one'side of the cabinet 2, encloses a combustion chamber 5 andv within the lower portion of said chamber is disposed a heating device 6 that may consist of an. oil burning unit. Suitably upported within the combustion chamber above the heating device is a'generator-absorber 7 from which a vapor conduit 8 rises to where it has connection with a coil 9 that is disposed within the upper portion of'a tank 10 that surmounts the cabinet 2. The coil 10 gradually rises to a point where it turns abruptly downwardly and joins, through a section 11, the upper end of a spherical shell 12 that encloses a smaller spherical shell 13 that is suitably sustained in spaced rblation to the former shell. A tube 14 leads from the bottom of the space between the shells 12 and 13 out through the side wall of the tank 10 and thence inwardly beneath the bottom wall 15 of the tank to where it is turned downwardly through the dome a of the receiver a and terminates at its lower end in a sump a of said vessel. By means of a pipe 16 that leads in through the rear-wall of the tank 10 and extends through the bottom of the outer shell 12 and joins the. corresponding portion of the inner shell 13, and a coiled pipe 17 that is similarly connected to th ner shell 13 and the aforesaid'wall is adapted to be shell 13.

The tank 10 is adapted to be filled, through an opening in its top that is normally closed by 'a cover 18, with water or a suitable cooling solution, and said tank, "with the parts enclosed thereby, constitutes the main condenser of the apparatus.

A gas return tube 20 leads from the'top of the dome a of the receiver over and downwardly into and a liquid return tube 21 extends from the sump constituted of the enlarged lower end of the column a upwardly through the leads outwardly through of the tank, cooling water circulated through the receiver and out through the dome thereof and thence over and downwardly into the generator-absorber to a point below the level of said sump. In order to prevent undue bubbling. of gas within the liquid retor absorber,

e upper portion of the in-.

the generator-absorber 7 ,turn tube 21, a bafiie 22 is disposed across reference may be had to the application of David F. Keith, Serial No. 242,574, filed December 27, 1927, and details of the main condenser herein illustrated are fully disclosed in an application filed by Lee S. Chadwick on the 27th day of April, 1929, Serial No. 358,468.

The system including the generator-absorber, the cooling unit, the condenser, and the conduits through which they communicate, is hermetically sealed and permanently contains a proper quantity of a suitable refrigerant, such as ammonia, and an absorbent therefor, such as water, in correct, proportions.

In describing the operation of the apparatus it will be assumed that to start with all or practically all of the liquid in the system is present in the generator-absorber 7. To

through the coil 9 that is submerged in the cooling solution contained in the tank 10 of of the condenser. All or centage of the absorbent vapors that rise with the refrigerant vapors from the generacondense within the coil 9 and flow back into the generator-absorber, the coil thus serving 'as a dehydrator. The refrigerant vapors pass on from the coil 9 through the section 11 to the refrigerant space of the main condenser between the inner and outer shells 12 and 13.

- As soon as boiling begins in the generatorabsorber the pressure rises throughout the system, butuntil it has attained a value that will cause the refrigerant vapors to condense at the temperature of the cooling water or solution in the main condenser, the vapors wilt pass on through the tube 14 into the. receiver a and thence through the tube a to the refrigerant space of the auxiliary condenser a. Here it should be explained that at the conclusion of each cycle of operation the brine within the auxiliary condenser is frozen, so that the refrigerant vapors now coming in contact-"with the inner wall of the auxiliary condenser condense and the re-; sultant liquid drains through tube 0: to the iower portion of the colunina from where' it. passes through tube a and cross tube a to the refrigerant spaces of the sectionsof the greater perthe evaporator a Inasmuch as the respective inner and outer walls of the auxiliary condenser and the sections of the evaporator are spaced very closely together, the capacity of the refrigerant spaces of said vessels is relatively small and consequently they soon become filled, the refrigerant condensate finally rising through the tubes 0. and entering the outer, upper ends of the refrig- "rant space of the auxiliary condenser. As the heating-condensing period continues, the pressure rises within the system and condensation of the refrigerant vapors now occurs in the refrigerant space of the main. condenser-and the condensate flows through the pipe 14 into the receiver a where it accumulates until, at the conclusion of said period, practically all the refrigerant has been driven out of solution and carried over into the receiver of the cooling unit. In the meanwhile, a thermo-siphon circulation of the refrigerant liquid is set up within the intercommunicating refrigerant spaces of the auxiliary condenser and the sections of the evaporator the liquid within the refrigerant space of the auxiliary condenser becoming c illed and descending through said space and through the tube a to the lower portion of the column a. from where it flowsthrough the tube a and cross tube a to the forward lower ends of the refrigerant spaces of the sections of the evaporator, the liquid within said latter spaces in the meantime becoming relatively warmer, by interchange of heat with the atmosphere in the cold space of the apparatus, and rising and passing through thetubes a. to the refrigerant space of the auxiliary condenser.

Upon discontinuance of the action of the heating device, the cooling-absorption period begins, ing to decline rapidly simultaneously therewith. Under the reduced internal pressure and the influence of the temperature of the atmosphere within the cold space, the anhydrous refrigerant in the evaporator starts to vaporize and the resultant gases flow back through the tube 20 to the generator-absorber where they are absorbed by the solvent within said vessel. By the evaporation of the anhydrous refrigerant, heat is abstracted from cold space and the temperature thereof is accordingly lowered as is also the temperature of the brine within the auxiliary condenser, the same again solidifying, if it has become softened during the previous heating-condensing period thereby reconditioning the auxiliary condenser for subsequent action on the warm refrigerant fluid.

The liquid return tube 21 functions during the early stages of the heating-condensing period to return any residue liquid left in thecvaporator end of the system at the conclusion of a cooling-absorption period to the generator-absorber. The manner which the pressure within the system startthis liquid return tube operates is clearly-set out in the above mentioned-application of David F. Keith.; y

In, Figs. 5 to 7 a -modified-construction of our improved cooling unit is illustrated, the same being designated generally by the reference character B, and consisting of a re- I ceiver b, auxiliary rator sections 6 The principal difference between this and the preceding form of the invention resides in the fact that, in the present case, the auxiliary condensers and evaporator sections are integral parts.

Each section of the evaporator and the corresponding auxiliary condenser has an outer tubular shell in common, the same being designated b This shell is open at its forward end and closed at its rear end. Disposed within and spaced from this outer shell are two cup-like shells b and b the rim of the latter being welded or otherwise secured to the peripheral portion of the end condensers-b, and evapowall of the former, while the open end of auxiliary condenser, enclosed by the shell I),

is adapted to be filled through an opening that is closed by a plug 11 The upper, rear portions of the refrigerant spaces of these combined evaporatorrcondenser units coinmunicate with thereeeiver 1) through tubes 1), while the lower rear portions of said spaces communicate witheach other through a cross tube b", A hollow column b rises from the middle of the cross tube and joins the receiver 1) adjacent the rear wall of the latter. The tube that delivers refrigerant fluid to the receiver. and the tubes throu h which the refrigerant gases and residue iquid are returned from the receiver and evap orator to the generator-absorber, in the mod-.

ification now under consideration," are designated by the same reference characters 'as are used to indicate the corresponding parts of the previous form.

The operation of the present form of the invention is substantially the same as that of the one first described and will therefore be readily understood without further explanation excepting to say that, in the case at hand, the circulation of the refrigerant condensate takes place wholly within the refrigerant spaces of the respective combined evaporator-condenser units. As the condensate is chilled by' contact with the shells b, it descends and displaces that which is below forwardly, and the latter, as it becomes warmer, rises up about the shells b and then flows rearwardly where, under the cooling influence of the auxiliary condensers, it

elongated cylindrical receptacles containing brine, and inclined downwardly and forwardly through them areportions of tubes 0 that lead from the lower, rear portion of the receiver to the lower, front portions of the refrigerant spaces of the evaporator sections. The bottoms of said spaces at the rear ends of the sections communicate with each other through a cross tube 0* from which a column rises and joins the bottom of the receiver. Tubes 0 extend from the upper, rear portions of the refrigerant spaces of the evaporator sections 0 to the tubes 0 at points intermediate the receiver and the auxiliary condensers. The refrigerant delivery, gas return, and residue liquid return tubes of'the, present embodiment are marked with the same reference characters as are applied to the like elements of the earlier forms.

The refrigerant vapors, at the beginning of a heating-condensing period, pass from the receiver .0, through the tubes 0 and are condensed and cooled while passing through the auxiliary condensers before being delivered to the evaporator sections. When suificientcondensate has accumulated to fill the refrigerant spaces of the evaporator sections and tubes 0 and 0, a therrno-siphon circulation is set up, the flow being upwardly through the refrigerant spaces and the tubes 0 and outwardly and downwardly through the tubes 0 as will be readily understood.

Having thus described our invention, what we claim is: o

1. In refrigeration apparatus of the intermittent absorption class, the combination of a generator-absorber, heating means therefor, a receiver, conduits through which the generator-absorber and receiver communicate, a main condenser for producing refrigerant condensate for delivery to the re ceiver, an evaporator communicating with the receiver, an auxiliary condenser, and conduits through which the receiver, evaporator and auxiliary condenser communicate, the parts being arranged so that when filled with liquid a thermo-siphon circulation willtake place if the liquid in the aum'liary condenser is at a lower temperature than that in the evaporator.

2. In refrigeration apparatus of the intermittent absorption class, the combination of a generator-absorber, means for heating the same,a receiver, conduits through which 7 the generator-absorber and receiver communicate, a main condenser for producing refrigerant condensate for delivery to the recelver, an evaporator communicating with,

ratorand so arranged with respect thereto that a thermo-siphon circulation of refrigerant liquid may take placethrough the evaporator and auxiliary condenser.

-3. In refrigeration apparatus of the intermittent absorption class, the combination of a generator-absorber, means for heating the same, a receiver, conduits through which the generator-absorber and receiver communicate, a main condenser for producing refrigerant condensate for delivery to the re-' ceiver, an evaporator communicating with and below the plane of the receiver and into which the receiver drains, and an auxiliary condenser in the'lineof comunication between the receiver and evaporator and so arranged with respect to the evaporator that a thermo-siphon circulation of'refrigerant liquid may take place through the evaporator and auxiliary condenser.

4. In refrigeration apparatus of the intermittent absorption class, the combination of a generator-absorber, means for heatin the same, a receiver, conduits through which the generator-absorber and receiver communicate, a main condenser for producing refrigerant condensate for delivery to the receiver, an evaporator communicating with and below the plane of the receiver and into whlch the receiver dralns, an auxiliary condenser 1n the lme of communicatlon between the receiver and the evaporator and through which drainage from the former to the latter takes place, and further means of com munication between the evaporator, and the auxiliary condenser whereby a thermo-siphon circulation of refrigerant liquid may take place through the evaporator and auxiliary condenser.

5. In refrigeration apparatus of the intermittent absorption class, the combination of evaporator and the corresponding portion of 'the auxiliary condenser whereby, when the auxiliary condenser and evaporator are filled with refrigerant condensate, such condensate is capable of a thermo-siphon circulation through the evaporator and aum'liary'condenser.

6. In refrigeration apparatus of the inter mittent absorption class, the combination, of

a generator-absorber, means for heating the.

the auxiliary condenser and through which tor, and conduits the refrigerant liquid is caused to circulate a thermo-siphon action.

7 A cooling unit for refrigeration apparatus of the intermittent absorption class comprising a receiver, a condenser, an evaporathrough which communication is established between the receiver, condenser and evaporator, the parts being so arranged that the -refrigerant condensate is capable of a thermo-siphon circulation through the evaporator and condenser.

cooling unit for refrigeration apparatus of the intermittent absorption class comprisinga receiver, a condenser, an evaporator, and conduits through which communication is established between the receiver, condenser and evaporator, the parts being so arranged that refrigerantvapors delivered to the receiver will pass through .the condenser and be condensed and cooled therein and the resultant liquid will flow by gravity to the evaporator and upon an accumulation of sufficient li uid to" fill the evaporator and condenser, a t ermo-siphon circulation will be set up through. the evaporator and condenser.

9. A cooling unit for refrigeration apparatus of the intermittent absorption class comprising a receiver, a condenser situated below the plane of the receiver, an evaporator having its lowerportion below the plane of the corresponding ortion of the condenser, means estab is ing communication between the lower portion of the receiver and the bottom portion of the evaporator and including the condenser, and communicative means between the upper portion of the evaporator and the corresponding portion of the condenser.

10. A coolin ,unit for refrigeration apparatus of the mtermittent absorption class, comprising a receiver, a condenser consisting of a double wall vessel, the walls whereof are spaced apart to provide thereb'etween a refrigerant s ace, the inner wall constituting a receptac e, a cooling agent contained therein, an evaporator, means of communication between the bottom portion of the receiver and the refrigerant space of the condenser and between the lower portion of said space and the bottom portion of the evaporator, and means of communication between the upper portion of the evaporator and the corresponding portion of the refrigerant space of the condenser.

. 11. A cooling unit for refrigeration apparatus of the intermittent absorption class, comprising a receiver, an evaporator, a condenser consisting of a double wall vessel, the

walls whereof are spaced apart to provide.

between the upper portion of the evaporator and the corresponding portion ofthe refrigerant space of the condenser. i

12. A cooling unit for refrigeration apparatus of the intermittent absorption class comprising a receiver,- a condenser located below the receiver and consistin of a don ble wall vessel, the walls whereo are spaced apart to providetherebetween a ref r1gerant space, the inner wall constituting a receptacle containing a body of brine, a pair of evaporators having refrlgerant spaces whose lower. portions are below the corres onding oi the con enser, a hollow column communieating with the receiver and depending from the bottom wall thereof between the eva orators and terminating at its lower end elow the level of the bottoms of the evaporators, the lower portion of said column constituting a sump, a cross tube through WhlCh the lower portions of the refrigerant spaces of the evaporators. communica e, a condu1t leading from the bottom portion of the receiver to the .top portion of the refrigerant space of the condenser, a second condu1t leading from the bottom portion of sa1d s ace to the sump, a conduit leading from' t e sump to the aforesaid cross tube, conduits leading from the upper portions of the refrigerant spaces of t e evaporator to the refrigerant space of the condenser, and a li uid conveying tube extending downwar y through the evaporator and throughthe column and terminating at its lower end within, said sump.

'13. A coolin unit for refrigeration apparatus of. the intermittent absorption class comprising a receiver in the nature of an elongated vessel a condenser consisting of a double wall elongated vessel that is disposed transversely of and below the rear ortion of the refrigerant space.

end of the receiver and whose walls are spaced apart to provide therebetween a refrigerant space, the inner wall enclosing a spaoefor a cooling agent, two double wall evaporator tubes arranged below and sub- 7 stantially parallel with the front portion of the receiver'and whose lower portions are below the plane of 'the corresponding portion of the condenser, the spaces between the walls of the respective evaporator tubes constituting refrigerant spaces, a cross tube through which the lower front portions of the refrigerant spaces of the evaporator tubes communicate, a hollow column communicating with the'receiver and depending from the bottom wall thereof, the lower en of'said column bein closed and constituting a sum that iselow the'plane of the bottoms o the evaporator tubes, a'conduit leading from the bottom vof the receiver to the top of the refrigerant space of the condenser, a second conduit leading from the.

bottom of said s ace to thea foresaid sump, a third conduit l eadiniefrom saidsum to the aforesaid cross tu conduits leading from the upper rear portions ofthe refrigerant spaces of the evaporator tubes to the upper end portions of the refri erant space- 0 the condenser, and a liqui conveying tube extending downwardly through the r ceiver and into the aforesaid column and having its. receiving end opening into the sump formed by the lower portion of said column. 7

In testimony whereof, we hereunto aflix our signatures. P

'LEE S. CHADW'ICK. MARC RESEK.

WILBUR G. am;

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