USRE25782E - Absorption refrigeration apparatus - Google Patents

Description

-May 1s, 1965v G A.GRUBB l Re. 25,782

ABSORPTION REFRIGERATION APPARATUS ZBY JINVENTOR.

Arran/vir May 18, 1965 G. A. GRUBB Re. 25,782

BSORPTION REFRIGERATION APPARATUS Original Filed Aug. 29. 1961 5 Sheets-Sheet 2 INVENTOR.

uw @wp/ZM May 18, 1965 G. A. GRUBB ABSORPTION REFRIGERATION APPARATUS s sheets-sheet s Grignal Filed Aug. 29, 1961 INV TOR. im MEM huw/yf 4 Arramvfr United States Patent O 25,782 ABSQRPTION REFRIGERATION APPARATUS Gunnar Axel Grubb, Broxnma, Sweden, assigner to Aktiebolaget Electrolux, Stockholm, Sweden, a corporation of Sweden Original No. 3,093,978, dated June 18, 1963, Ser. No. 134,760, Aug. 29, 1961. Application for reissue June 12, 1964, Ser. No. 386,470

Claims priority, application Sweden Sept. 22, 1960 12 Claims. (Cl. 62-236) Matter enclosed in heavy brackets 1 appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

My invention relates to absorption refrigeration apparatus of the kind in which vapor is expelled out of solution by heating.

Itis an object of the invention to provide for absorption refrigeration apparatus improved heating structure for conveniently heating the apparatus by different sources of heat.

Another object is to provide for a vapor-expulsion unit of absorption refrigeration apparatus an electrical heating element and a fluid fuel burner for heating a heating tube of heat receiving structure and controlling the sources of heat for selectively rendering either the electrical heating element or the fuel burner operable to heat the heating tube.

A further object is to provide a duid fuel burner and several electrical heating elements adapted to be energized with different kinds of electrical energy for heating a heating ue of heat receiving structure of absorption refrigeration apparatus and controlling the sources of heat for selectively rendering a single source of heat operable to heat the heating tube.

The invention, together with the above and other objects and advantages thereof, will be more fully understood upon reference to the following description and the accompanying drawing forming a part of this specification, and in which:

FIG. 1 illustrates more or less diagrammatically parts of absorption refrigeration apparatus to which the invention is applied, the apparatus being shown in an upright space at the rear of a refrigerator and adapted to be operated by a fluid fuel burner;

FIG. 2 is a View similar to FIG. l with the refrigeration apparatus adapted to be operated by an electrical heating unit;

FIG. 3 is a fragmentary sectional view taken at line 3-3 of FIG. 1;

FIGS, 4 and 5 are elevational views of electrical heating units like the heating unit shown in FIG. 2;

FIG. 6 is a fragmentary perspective view of a detail which may be embodied at the rear of the refrigerator shown in FIGS. l and 2; and

FIG. 7 is a fragmentary view taken at line 7-7 of FIG. 1.

Referring to FIG. l, the invention is shown in connection with a refrigerator which comprises a cabinet 10 supported on legs 11. The lateral side walls 12 of the cabinet extend rearward beyond a rear plate 14 to provide a vertical compartment 15 in which parts of absorption refrigeration apparatus are housed. During operation of the refrigeration apparatus, natural draft circulation of air is induced to effect air-cooling of an absorber 16 and a condenser (not shown), such cooling air flowing upward through an opening 17 in the bottom Re. 25,782 Reissued May 18, 1965 ice of the cabinet and passing through openings 18 in an apertured rear part of the top 19 of the cabinet.

The absorption refrigeration apparatus is of a uniform pressure type containing an inert gas or pressure equalizing gas. Refrigerant vapor is expelled from absorption liquid in a vapor lift pipe 20 of a vapor-expulsion unit 21 and passes through the upper part of a standpipe 22 and a conduit 23 to a condenser. The refrigerant vapor, such as ammonia, is liquefied in the condenser and ows into an evaporator in which the refrigerant evaporates and diffuses into an inert gas, such as hydrogen, to produce a refrigerating effect within the thermally insulated interior of the cabinet 10. The resulting gas mixture of refrigerant and inert gas liow from the evaporator to an absorber which may be of an air-cooled type including the coil 16 and an absorber vessel 24 to which the lower end of the coil is connected, such gas mixture entering the absorber vessel 24 through a conduit 25.

In the absorber refrigerant is absorbed from the gas mixture into absorption liquid, such as Water, which is delivered thereto through a conduit 26, and the absorption liquid enriched in refrigerant passes into the absorber vessel 24. The inert gas is returned from the absorber to the evaporator in the path of iiow including a conduit 27, and the enriched absorption liquid is conducted through a conduit 28 and inner pipe 29 of a liquid heat exchanger 30 to the vapor-expulsion unit 21.

The absorption liquid from which refrigerant vapor has been expelled tiows by gravity from standpipe 22 through the outer pipe 32 of liquid heat exchanger 30 and conduit 26 into the upper part of absorber coil 16. The liquid surface level A maintained in standpipe 22 is at a higher level than the region at which liquid is introduced into absorber 16 from the upper end of conduit 26. ln order to simplify the drawing, the condenser, evaporator and connections therefor have not been shown, such parts being well known and their illustration not being necessary for an understanding of this invention.

Absorption solution enriched in refrigerant flows from the absorber vessel 24 through conduit 28 and inner pipe 29 of liquid heat exchanger 30 into the lower end of vapor lift pipe 20 which is in thermal exchange relation with a heating tube 33 at 34, as by welding, for example.

The part of the pump or lift pipe 20 in thermal exchange relation with the heating tube 33 may be referred to as the vapor-forming part in which vapor bubbles are formed due to heat derived from the heating tube. Due to the formation of these vapor bubbles which tend to collect and become larger and larger, liquid in the vapor lift pipe 20 becomes segregated, whereby slugs of liquid are caused to rise in the lift pipe by vapor lift action. Vapor generated in the vapor lift pipe 20 flows from the upper end thereof through the upper part of standpipe 22 into conduit 23 and passes to the condenser, as previously explained.

The vapor-expulsion unit 21 in its entirety, together with a major portion of the liquid heat exchanger 30, are embedded in a body of insulation 35 retained in a metal shell o-r casing 36 having an opening 37 at the bottom thereof, the shell being rectangular or circular in horizontal cross-section. The heating tube 33, which is embedded in the insulation 35, is formed with an enlarged bottom section 33a which projects through the bottom opening 37 in the casing 36. The upper end of the heating tube 33 projects through a top opening 38 in the casing 35 and includes an extension 33h which terminates at the top 19 of the cabinet. The rear part of the top 19 of the cabinet is provided with a removable apertured section 19a having an opening 19h through which the upper extension 33b of the heating tube eXtends.

As shown in FIG. 1, a gaseous fuel burner 40, which may be supported in any suitable manner in the enlarged bottom section 33a of the heating tube 33, is provided with a burner head 40a positioned at the top part of the enlarged tube section. A gap of suitable size is formed between the burner 40 and bottom heating tube section 33a to provide a passage for secondary air which will insure complete combustion of the mixture of gaseous fuel and primary air discharged from the burner head 46a. The burner 40 is connected to a source of supply of gaseous fuel by a pipe 41 in which is connected a valve 42. The burner 40 serves as a gus burner heating element operable to maintain a flame burning in the atmosphere for producing combustion gases at an elevated temperature and capable of functioning to heat the heut receiving par! or tube 20 of the vapor expulsion unit 21 to expel vapor out of solution therein by heut derived from the combustion gases substantially at the elevated temperature.

In accordance with my invention, the heating tube 33 may be employed as a component part of heating structure adapted to be employed with a gaseous fuel burner in the manner just described and illustrated in FIG. l; and also as a component part of heating structure adapted to be employed with an electrical heating unit in the manner illustrated in FIG. 2. In FIG. 2, in which parts similar to those shown in FIG. 1 and described above are referred to by the same reference numerals, an electrical heating element 43a is positioned Within the heating tube 33. The heating tube 33 snugly receives the heating elernent 43a which may comprise a cartridge housing an elec- :rical `wire or the like having a relatively high resistance :hat generates heat when connected to a source of electri- :al energy.

The heating element 43a forms the bottom part of a sortable heating unit 44a which is positioned within the ieating ltube 33 [form] from its upper open end. The ieating unit 44a includes a narrower upper part 45a which nay be formed of suitable insulating material and a collar raving a tlange 46a for holding the heating unit at the up- )er open end of t-he heating tube 33. The heating unit 44a s of such length that the heating element 43a will be posiioned in that part of heating tube 33 to which the pump )r lift pipe 20 is heat conductively connected thereto at i4. As shown in FIG. 4, the heating unit 44a is conrected by an electrical cord 47a to a terminal fitting or lug 48a adapted to be connected to an outlet socket 49a rovided in any suitable manner in the upper part of the ear vertical compartment of the cabinet 10.

In accordance with my invention, I provide the heating init 44a for the heating tube 33 which is adapted to be onnected to a conventional source of electrical supply Sti nd a second heating unit 44h for the heating tube 33 /hich is adapted to be connected to a battery 51. When he heating unit 44a is positioned in the heating tube 33 nd its terminal tting 48a is connected to the outlet ocket 49a, a circuit will be completed for the heating lement 43a when switch 52 is closed. From one side of 1e source of electrical supply 50 this circuit ywill include onductors 53, 54, switch 52 and conductor S5 4back to 1e other side of the source of electrical supply Si).

The heating unit 44b for battery operation is similar to 1e heating unit 44a and includes a heating element 43h, rsulating portion 45h, collar 46h, cord 47b and terminal tting 48h, When the heating unit 44b is positioned in 1e heating tube 33 and its terminal fitting 48b is conected to an outlet socket 49h, a circuit will be completed r the heating element 43h when switch 56 is closed. rom one terminal .of the battery 51 this circuit will inude conductors 57 and 58, switch 56 and conductor 59 ick to the other terminal of the battery.

Plates 64) and 6l, which are respectively fixed to the top 1d bottom of the casing 36, are apertured to receive a :rtical shaft or rod 62.to which is fixed a collar 63 adapted to rest on the top plate 60. The rod or snaft 62 is provided with a control knob 64 at its upper end. To a part of the shaft 62 below the knob 64 and above top plate 66 is xed an arm 65. A ilat horizontal part 66 which projects radially outward from the periphery of the arm 65 can be moved into and from a slotted portion 67 of the heating flue extension 33h.

The valve 42 for controlling the supply of gaseous fuel to the burner 40 includes a casing 42a of cylindrical shape which may be fixed to the bottom plate 61. Within the casing is positioned a rotatable valve member 42h iixed to the shaft 62. The valve member 42h is formed with a passage 42o which connects the pipe 41 and burner 4t] when the valve member is in the position illustrated in FIG. 3.

Each -of the switches 52 and 56 may comprise a member of cylindrical shape which is formed of electrically conductive material and liXed to the shaft 62 and insulated therefrom in any suitable manner. Brushes 54a and 55a, to which the conductors 54 and 5S are connected, are adapted to lbear against the periphery of switch 52; and brushes 56a and 59a, to which the conductors 58 and 59 are connected, are adapted to bear against the periphery of switch 56. The peripheries of the switch members 52 and 56 are provided with insulating sections 52a and 56a, respectively, over which the brushes move for a part of each complete turn of the shaft 62.

When the knob 64 is turned so that valve 42 will be open and in the position illustrated in FIG. 3 to deliver gaseous fuel to the burner 49, the outer flat part 66 of arm 65 will be positioned in the slotted portion 67 of the heating tube extension 33h. Therefore, when it is desired to operate the refrigeration apparatus with the gas burner 40, it is necessary to remove either one of the heating units 44a or 44b from the heating llue 33 if this already has not been done. Also, the flat member 66 projecting into the heating tube extension 33a during gas operation of the refrigeration apparatus will prevent anyone from positioning a heating unit in the heating tube. During gas operation, the heating units 44a and 44h may be stored in the rear apparatus compartment 15. As shown in FIGS. l, 2 and 7, the plate 60 is formed with a pair of openings 68 through which the heating units may be inserted, the anges 46a and 46h of the heating units being sufliciently large to engage the plate 60 :at the openings and support the heating units.

Desirably, the relationship of valve member 42h and the insulating sections 52a and 56a of the switches is such that in a rst position of knob 64 the valve 42 is partly or fully open and the brushes engage the insulating sections 52a and 56a of the switch members 52 and 56, and in a second position o-f knob 64 the valve 42 is close-d and the brushes are removed from the insulating sections 52a and 56a :of the switch members. Hence, the control knob 64 can be moved either to one of two positions, namely, a rst valve on position, or a second position which will render either one of the heating units 44a or 44h operable to effect heating of the refrigeration apparatus when it is positioned in the heating tube 33. In the second position .of control knob 64 the iiat part 66 of arm 65 will be in the position illustrated in FIG. 2 ttobpermit a heating unit to be inserted into the heating In FIGS. 4 and 5 it will be seen that the terminal fitting 46a for the heating unit 44a is provided with round pins 69a While the terminal fitting 48h for the heating unit 44h is pro-vided with flat blade 69h. The outlet socket 49a associated with the conventional source of electrical supply 50 is formed with round openings 49a adapted to receive the pins 69a of the terminal fitting 48a, while the outlet socket 49h associated with the battery 51 is formed with narrow rectangular slots 49h adapted to receive the llat blades 69h of the terminal fitting 48h. Hence, the heating units 44a and 44h, each of which is designed to operate with a particular kind of electrical energy, cannot inadvertently be connected to the wrong kind Aof electrical energy.

The outlet sockets 49a and 49h may be positioned in the rear apparatus compartment in diierent walls 70 and 71 which are perpendicular to one another, as shown in FIG. 6. The outlet sockets may be placed close to the junction of the walls 76 and 71 so that when the terminal fitting of one heating unit is connected to its outlet socket, that terminal fitting will be located in front of the other outlet socket and prevent the other terminal fitting from being positioned therein. Hence, even when the control knob 64 is moved to such a position that either one of the electrical heating units will be rendered operable to effect operation of the refrigeration apparatus, only one of the heating units can be connected to its associated source of electrical supply when the outlet sockets are located in the rear apparatus compartment in the marmer illustrated in FIG. 6 and described above.

By providing the removable apertured section 19a at the rear part of the top of the cabinet, easy access to the upper part of the rear storage space can be obtained to manipulate control knob 64 and shift an electrical heat- 'ing element from the heating flue 33 to the plate 60- for storage in one of the openings 68 therein or from such storage position to the heating flue 33. In vew of the foregoing, it will now be understood that the gas pipe 4] functions as a means for supplying gas energy in the form of a combustible gas to the burner 40, and that the electrical conductors 53, 54 and 55 function as a means for conducting electrical energy to the electrical heating unit 44a. In FIGS. 1 and 2 the switch mechanism 52 and valve mechanism 4Z and controls operatively associated with these mechanisms constitute means for selectively connecting the gas pipe 41 to the burner 40 or the electrical conductors to the electrical heating element 43a whenever both electricity and gas are available as sources of power for the refrigeration system. The shaft 62 which is provided with the control knob 64 and to which the apertured rotatable valve member 42h and switch mechanism 52 are hxed form components of the selective connecting means and may be operated at will to obtain the desired source of power for the refrigeration unit.

As explained above, the rod 62 is operable to actuate the valve mechanism 42 at will to connect the gas pipe 41 to the burner 40 only when the electrical conductors 53, 54 and 55 are disconnected from the source of electrical supply 50 by the switch mechanism 52; and the rod 62 is operable to actuate the switch mechanism 52 to energize the heating element 43a from the source of electrical supply 50 only when the gas pipe 4Z is disconnected from the burner 40 by the valve mechanism 42.

While l have shown and described a single embodiment of my invention, it will be apparent that modiiications and changes may be made without departing from the spirit and scope of the invention, as pointed out in the following claims.

I claim:

l. In absorption refrigeration apparatus, an upright shell having an upstanding side wall and a top and bottom and insulation therein, a vapor-expulsion unit embedded in the insulation, said vapor-expulsion unit having at least one part in which vapor is expelled from solution by heating, an upright heating tube which extends through said insulation between the top and bottom -of said shell, the top and bottom of said shell having openings communicating with the upper and lower ends of said heating tube, means heat conductively connecting the exterior surfaces of said tube and said part along a zone which extends lengthwise of said tube, said heating tube being hollow, an electrical heating element, means for removably positioning said heating element in said tube through its upper open end to locate said heating element vertically at said zone for operating the apparatus electrically, means including a fluid fuel burner positioned at the lower end of said heating tube for operating the apparatus with a combustible fuel mixture, the part of said heating tube at said zone having its inner surface in the path of flow of combustion gases produced during operation of the burner, and control means for rendering said electrical heating element operable to heat said heating tube and for rendering said fluid fuel burner operable to heat said heating tube, said electrical heating element being removed from said heating tube at its upper end when said uid fuel burner is rendered operable to heat said heating tube, said control means including structure for blocking said heating tube to prevent the insertion of said electrical heating element therein responsive to rendering said fluid fuel burner operable to heat said heating tube.

2. In absorption refrigeration apparatus, an upright shell having an upstanding side wall and a top and bottom and insulation therein, a vapor-expulsion unit embedded in the insulation, said vapor-expulsion unit having at least one part in which vapor is expelled from solution by heating, an upright heating tube which extends through said insulation between the top and bottom of said shell, the top and bottom of said shell having openings communicating with the upper and lower ends of said heating tube, means heat conductively connecting the exterior surfaces of said tube and said part along a zone which extends lengthwise of said tube, said heating tube being hollow, an electrical heating element, means for removably positioning said heating element in said tube through its upper open end to locate said heating element vertically at said zone for operating the apparatus electrically, means including a fluid fuel burner positioned at the lower end of said heating tube for operating the apparatus with a combustible fuel mixture, the part of said heating tube at said zone having its inner surface in the path of flow of cornbustion gases produced during operation of the burner, control means for rendering said electrical heating element operable to yheat said heating tube and for rendering said fluid fuel burner operable to heat said heating tube, said electrical heating element being removed from said heating tube at its upper end when said uid fuel burner is rendered operable to heat said heating tube, an electrical circuit for said electrical heating element having switch means and a fluid fuel line for said burner having a valve, and said control means including a manually operable part at the vicinity of the upper open end of said heating tube which is movable to two positions, said control means being effective to close said switch means and shut said valve in one position of said -part and to open said switch means and open said valve in the other position of said part. I

3. In absorption refrigeration apparatus, an upright shell having an upstanding side wall and a top and bottom and insulation therein, a vapor-expulsion unit embedded in the insulation, said vapor-expulsion unit having at least one part in which vapor is expelled from solution by heating an upright heating tube which extends through said insulation between the top and bottom of said shell, the top and bottom of said shell having openings cornmunicating with the upper and lower ends of said heating tube, means heat conductively connecting the exterior surfaces of said tube and said part along a zone whicl extends lengthwise of said tube, said heating tube being hollow, an electrical heating element, means for removably positioning said heating element in said tube througl its upper open end to locate said heating element verti` cally at said zone for operating the apparatus electrically means including a fluid fuel burner positioned at the loWe: end of said heating tube for operating the apparatus witl a combustible fuel mixture, the part of said heating tubi at said zone having its inner surface in the path of ov of combustion gases produced during operation of thl burner, control means for rendering said electrical heat ing element operable to heat said heating tube and fo rendering said fluid fuel burner operable to heat said heat ing tube, said electrical heating element being remove from said heating tube at its upper end when said fluit fuel burner is rendered operable to heat said heating tube, another electrical heating element and an electrical circuit for each of said elements, switch means for each of said circuits, and a fluid fuel line for said burner having a valve, and said control means including a manually movable part which is movable to two positions, said control neans being effective to close both of said switch means and shut said valve in one position of said part and to open )oth of said switch means and open said valve in the other Josition of said part, each of said electrical circuits havng an outlet socket, each of said electrical heating elenents having a terminal fitting, said outlet sockets being aositioned so that either terminal fitting in its outlet socket vill prevent the other outlet socket from receiving the lther terminal fitting.

4. A refrigerator comprising a cabinet having an apraratus space at an upright wall thereof, an apertured art, means for removably supporting said apertured part Iver the apparatus spaced at the top of the cabinet, re-

rigeration apparatus including an upright shell positioned 1 the apparatus space, said shell having an upstanding ide wall and a top and bottom and insulation therein, a apor-expulsion unit embedded in the insulation, said vaor-expulsion unit having at least one part in which vapor expelled from solution by heating, an upright heating .lbe which extends through said insulation between the )p and bottom of said shell, the top and bottom of said lell having openings communicating with the upper and )wer ends of said heating tube, the upper end of said eating tube terminating at the vicinity of the top of the ibinet, means heat conductively connecting the exterior lrfaces of said tube and said part along a zone which (tends lengthwise of said tube, said heating tube being allow, an electrical heating element, means for remov- Jly positioned said heating element in said tube through s upper open end to locate said heating element ver- :ally at said zone for operating the apparatus electrically, eans including a iiuid fuel burner positioned at the wer end of said heating tube for operating the apparas with a combustible fuel mixture, the part of said heatg tube at said zone having its inner surface in the path `ow of combustion gases produced during operation of e burner, control means for rendering said electrical :ating element operable to heat said heating tube and r rendering said iiuid fuel burner operable to heat said l.ating tube, said electrical heating element being rcoved from said heating tube at its upper end when said lid fuel burner is rendered operable to heat said heating be, and said control means including a manually movle control part in the apparatus space at the vicinity of e upper end of said heating tube, said control part being cessible upon removal of said apertured part. 5. Apparatus as set forth in claim 4 which includes other electrical heating element and an electrical cirit for each of said elements, switch means for each of .d circuits and a fuel line for said burner having a valve, d movable control part being movable to two posins, said control means being effective to close both of d switch means and shut said valve in one position of d control part and to open both of said switch means d open said valve in the other position of said control rt, each of said electrical circuits having an outlet :ket in the upper part of the apparatus space, means the upper part of the apparatus space for storing at st one of said electrical heating elements, and said ctrical heating elements having terminal fittings which er from one another, and one of said outlet sockets eiving only one of said terminal fittings and the other said outlet sockets receiving only the other of said ninal fittings. i. In absorption refrigeration apparatus, an upright ll having an upstanding side wall and a top and bot- 1 and insulation therein, a vapor-expulsion unit emlded in the insulation, said vapor-expulsion unit havat least one part in which vapor is expelled from 75 solution by heating, an upright heating tube which extends through said insulation between the top and bottom of said shell, the top and bottom of said shell having openings communicating with the upper and lower ends of said heating tube, means heat conductively connecting the exterior surfaces of said tube and said part along a zone which extends lengthwise of said tube, said heating tube being hollow, an electrical heating element, means for removably positioning said heating element in said tube through its upper open end to locate said heating element vertically at said zone for operating the apparatus electrically, means including a fiuid fuel burner positioned at the lower end of said heating tube for operating the apparatus with a combustible fuel mixture, the part of said heating tube at said zone having its inner surface in the path of fiow of combustion gases produced during operation of the burner, control means for rendering said electrical heating element operable to heat said heating tube and for rendering said fluid fuel burner operable to heat said heating tube, said electrical heating element being removed from said heating tube at its upper end when said fluid fuel burner is rendered operable to heat said heating tube, said heating tube being formed with an opening in its wall, and said control means including a part movable into the interior of said heating tube through the opening in its wall to block the insertion of said electrical heating element therein responsive to rendering said fluid fuel burner operable to heat said heating tube.

7. In combination with a refrigerating system of the type alternatively employing gas or electricity as power sources and in which cooling is eected by a refrigeration unit having u heat receiving part, of a gus burner heating means adapted to heut the heut receiving part, means for supplying gas energy to scid burner heating means, electrical heating means adapted to heat the heut receiving part, means for conducting electrical energy to said electrical heating means, valve means in said gas energy supply means, switch means in said electrical energy conducting means, means for controlling said switch means and said valve means to render said electrical heating means operable to heat the heat receiving part or to render said burner heating means operable to heat the heat receiving part, said control means including u member rotatable about an axis to first and second positions, said valve means including a rotatable element which forms a unitary port of said rotatable member, said rotatable member having a portion which is operatively associated with said switch means, said control means being ejecn've to close said switch means and shut said valve means upon movement of said rotatable member to said first position and to open said switch means and open said valve means upon movement of said rotatable member to said second position.

8. In combination with a refrigerating system of the type alternatively employing gas or electricity as power sources and in which cooling is eected by u refrigeration unit having a heat receiving part, of a gas burner heating element adapted to heat the heat receiving part, means for supplying gus energy to said burner heating element, an electrical resistance heating element adapted to heat the heut receiving pdrt, means for conducting electrical energy to said resistance heating element, and switching means connected to said gas energy supply means and to said electrical energy conducting means and adapted simultaneously to connect a first of said energy means to its associated heating element and to disconnect the second of said energy means from its associated heuting element or to connect the second of said energy means to its associated heating element and to disconnect the first of said energy means from its associated heating element, said switching means comprising an electrical switch which is coupled to said electrical energy conducting means und to said resistance heating element and includes a movable parl for completing and interrupting electrical continuity therethrough, a rotatable member operatively associated with said movable part of said switch for closing said switch to complete electrical continuity therethrough at first particular angular orientations of said rotatable member and to interrupt electrical continuity at other orientations of said rotatable member, a valve having a rotatable plug with a passage therethrough, said valve being coupled to said gas energy supply means and to said gas burner heating element for permitting the flow of gas through said valve at second particular orientations of said rotatable plug and for obstructing the flow of gas through said valve at other orientations of said rotatable plug, and means for simultaneously rotating said rotatable member and said rotatable plug, said rotatable member and said rotatable plug being disposed such that a fixed angular diyerence is maintained between said first and second particular angular orientations.

`9. In combination with a refrigerating system of the type alternatively employing gas or electricity as power sources and in which cooling is eected by a refrigeration unit having a heat receiving part, of a gas burner heating element adapted to heat the heat receiving part, means for supplying gas energy to said burner heating element, an electrical resistance heating element adapted to heat the heat receiving part, means fo'r conducting electrical energy to said resistance heating element, and switching means connected to said gas energy supply means and to said electrical energy conducting means and adapted simultaneously to connect a first of said energy means to its associated heating element and to disconnect the second of said energy means from its associated heating element or to connect the second of said energy means to its associated heating element and to disconnect the first of said energy means from its associated heating element, said switching means comprising an electrical switch which is coupled to said electrical energy conducting means and to said resistance heating element and includes a movable part for completing and interrupting electrical continuity therethrough, a rotatable shaft, a member mounted on said shaft and rotatable therewith, said rotatable member being ope'ratively associated with said movable part of said electrical switch for closing said switch to complete electrical continuity therethrough at first particular angular orientations of said rotatable member and to interrupt electrical continuity at other orientations of said rotatable member, a valve having a plug with a passage therethrough, said valve being coupled to said gas energy supply means and to said burner heating element for permitting the flow of gas through said valve at second particular angular orientations of said rotatable plug and for obstructing the flow of gas through said valve at other orientations of said rotatable plug, said plug being mounted on said shaft and rotatable therewith, said rotatable member and said plug being mounted on said shaft such that said first and second particular orientations occur at dierent angular positions of said shaft.

10. In combination with a refrigerating system of the type alternatively employing gas or electricity as power sources and in which cooling is eected by a refrigeration unit having a heat receiving part, of a gas burner heating means adapted to heat the heat receiving part, means for supplying gas energy to said burner heating means, electrical heating means adapted to heat the heat receiving part, means for conducting electrical energy to said electrical heating means, and switching means connected to said gas energy supply means and to said electrical energy conducting means and adapted simultaneously to connect a first of said energy means to its associated heating means and to disconnect the second of said energy means from its associated heating means o'r to connect the second of said energy means to its associated heating means and to disconnect the first of said energy means from its associated heating means, said switching means comprising an electric switch which is coupled to said electrical energy conducting means and to said electrical heating means and includes a movable part for completing and interrupting electrical continuity therethrough, said gas supply means including a valve having a rotatable plug with a passage therethrough, and means coupling said rotatable plug to said movable part of said electric switch, whereby said plug opens said electric switch upon turning of said plug to a position opening said valve and said plug closes said electric switch upon turning of said plug to a position closing said valve.

1I. In combination with a refrigerating system of the type alternatively employing gas and electricity as power sources and in which cooling is effected by a refrigeration unit having a heat receiving part, of a gas burner heating element operable to maintain a flame burning in the atmospherer for producing combustion gases at an elevated temperature and capable of functioning to heat the heat receiving part by heat derived from said combustion gases substantially at said elevated temperature, means for supplying gas energy in the form of a combustible gas to said burner heating element, an electrical resistance heating element capable of functioning to heat the heat receiving part, means for conducting electrical energy to said resistance heating element, and means adapted to selectively connect either one of said energy means to its associated heating element whenever both electricity and gas are available as sources of power for the refrigeration system, said last-mentioned means comprising switching mechanism which is operable at will and connected to said gas energy supply means and to said electrical energy conducting means and adapted simultaneously to connect a first of said energy means to its associated heating element and to disconnect the second of said energy means from its associated heating element or to connect the second of said energy means to its associated heating element and to disconnect the hrst of said energy means from its associated heating element, said switching mechanism comprising valve means including a movable element connected to said gas energy supply means and electric switch means connected to said electrical energy conducting means and means including a movable member which forms a unitary part of said movable element for operatively associating said valve means and said eletcric switch means.

l2. In combination with a refrigerating system of the type alternatively employing gas and electrictity as power sources and in which cooling is eectcd by a refrigeration unit having a heat receiving part, `of a gas burner heating element operable to maintain a flame burning in the atmosphere for producing combustion; gases at an elevated temperature and capable of functioning to heat the heat receiving part by heat derived from said combustion gases substantially at said elevated temperature, means for supplying gas energy in the form' of a combustible gas to said burner heating element including a valve having a valve element movable at will to positions opening and closing the supply of gas to said burner heating element, electrical heating means capable of functioning to heat the heat receiving part, means for conducting electrical energy to said electrical heating means, and mechanism adapted to selectively connect either one of said energy means to its `associated heating element whenever both electricity and gas are available as sources of power for the refrigeration system, said last-mentioned mechanism comprising electric switch means which is connected to said electrical conducting means and includes a part shiftable responsive to movement of said movable valve element, said electric switch means opening upon shifting of said part thereof responsive to movement of said movable valve element to a position opening said valve to prevent flow of electrical energy to said electrical heating means, and said electric switch means closing upon shifting of said part thereof responsive to movement of said movable valve element to a position closing said valve l l 1 2 to allow flow of electrical energy to said elecrtcal heating UNITED STATES PATENTS means 2,009,067 7/35 Mulholland 62-148 References Cited by the Examiner gg Iennilng 62-489 The following references, cited by the Examiner, are of 5 000:19'76 9/61 Kgl record in the ptented le of :this patent or the original patent. ROBERT A. OLEARY, Primary Examiner.

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