US2031536A - Refrigerating apparatus - Google Patents

Description

Feb. 18, 1936.

J. G. KING REFRIGERATING APPARATUS Original Filed Dec. 50, 1935 2 Sheets-Sheet l INVE HIS ATTORNEYS.

Feb. 18, 1936. J KlNG 2,031,536

REFRIGERAT ING APPARATUS Original Filed Dec. 30, 1933 2 Sheets-Sheet 2 ER in o In IHHI llllll yEN I OR "IS ATTORNEYS.

Patented Feb. 18, 1936 UNITED STATES PATENT OFFICE 2,031,536 REFRIGERATING APPARATUS tion of Delaware Application December 30, 1933, Serial No. 704,680 Renewed July 17, 1935 11 Claims.

This invention relates to refrigerating apparatus and particularly to evaporators of such apparatus adapted to contain a quantity of liquid refrigerant.

One of the objects of the invention is to provide means whereby an excessive amount of oil will be prevented from accumulating in an evaporator of a refrigerating system.

Another object of the invention is to provide an improved device for returning oil from an evaporator to a compressor of a refrigerating system which device is arranged to prevent the return to the compressor of liquid refrigerant during a temporary increase in the level of refrigerant in the evaporator.

A still further object of the invention is to provide an improved outlet device for a liquid cooling apparatus of the type including a. liquid cooling coil or conduit submerged in a body of liquid refrigerant contained in the evaporator of the refrigerating system which device prevents the entrance of liquid refrigerant thereto.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. l is a sectional view of an evaporator having the invention incorporated therein and showing diagrammatically a refrigerant liquefying and condensing unit operativelyconnected to the evaporator;

Fig. 2 is a view similar to Fig. 1 showing the position of the device of the invention during a period of increased level of refrigerant in the evaporator; and

Fig. 3 is a view taken on the line 33 of Fig. 1 showing a horizontal cross-section of the outlet device or conduit incorporated in the evaporator of the present invention.

One of the problems in connection with a refrigerating system is that of the circulation through the system of the lubricant supplied to the compressor for lubricating the moving parts of the compressor. The vaporized refrigerant is generally drawn to the compressor by suction created by a pumping action in the compressor and upon being compressed is forwarded under pres- 53) sureto the other elements of the refrigerating system. This process of suction, compressing and forwarding under pressure is apt to churn the lubricant or oil into a foamy state and to carry a certain portion of it to other parts of the refrigerating system where it is not desired. Furthermore, as the compressor generally has the pumping action referred to, a certain portion of the oil is mechanically carried along with the refrigerant in addition to that absorbed by the refrigerant. This oil eventually reaches the evap- 5 orator and where a refrigerant such as sulphur dioxide is used the oil will form a blanket on the top of the liquid refrigerant in the evaporator. If too much oil is drawn from the compressor it may result in the moving parts of the compressor 10 being damaged for want of suflicient lubrication. If the oil blanket becomes very thick on the surface of the liquid refrigerant in the evaporator it decreases the efl'iciency of the apparatus by taking the place of liquid refrigerant, and'fur- 5 thermore, by hindering suitable vaporization of the liquid refrigerant. Accordingly it is one of the objects of this invention to provide means for returning oil to the compressor so as to prevent the accumulation of an excessive amount 20 thereof in the evaporator.

In addition to the foregoing mentioned problems it is also a problem to prevent any liquid refrigerant from returning from the evaporator to the compressor with the oil. This latter prob- 2.5 lem is inherently present, particularly in apparatus wherein liquid cooling coils or conduits are submerged in the liquid refrigerant contained in the evaporator and utilized for circulating water, beer or other beverages through the evaporator 30 to be cooled prior to dispensing the same. It has been found that devices for returning oil and gaseous refrigerant only from an evaporator to a compressor of a refrigerating system wherein the evaporator thereoj, is employed or utilized to cool the interior of a refrigerator cabinet or the like are not entirely satisfactory when incorporated in a water, beer or other beverage coolers of the type herein disclosed. In liquid coolers, and particularly water and beer coolers, wherein a great amount of beer, water or other beverages to be cooled is suddenly circulated in thermal contact with liquid refrigerant within the evaporator, a great amount of heat units are suddenly transferred or given up to the refrigerant thus causing violent ebullition of refrigerant below the level .thereof in the evaporator. This violentebullition and vaporization of the refrigerant below the level thereof in the evaporator causes the entire body of liquid refrigerant to expand or swell, almost into a foam-like mass due to the generation of or abnormal quantity of gas bubbles accumulating and flowing upwardly in the body of liquid refrigerant. The level of the body of liquid refrigerant and oil contained in the evaporator is therefore temporarily greatly increased. If no provision is made to raise the intake portion or to close lower portions of the intake openings in that portion of the suction line extending into the evaporator relative to and simultaneously with the raising of the level of refrigerant in the evaporator, liquid refrigerant will flow into the intake opening or openings in the gaseous refrigerant return line and will be drawn by suction of the compressor through the suction line to the compressor crankcase. Liquid refrigerant upon being drawn into the gaseous refrigerant return line and vaporized therein will cause frosting over of this line which extends between the evaporator and the compressor thus warping or causing other damage to the floor or its coverings. This frosting of the return line also increases the cost of operation due to the loss of efficiency on account of the liquid refrigerant not being evaporated or vaporized in the evaporator. It is therefore the main object of this invention to prevent the return of liquid refrigerant from the evaporator to the compressor particularly in a system wherein the level of a body of liquid refrigerant in the evaporator intermittently or periodically changes while at the same time insuring the return of oil to the compressor along with gaseous refrigerant during normal evaporation of refrigerant in or from the evaporator.

In Figs. 1 and 2 of the drawings there is disclosed a type of evaporator embodying a preferred application of the invention. This evaporator, generally referred to by the numeral I0, is preferably of the well-known flooded float controlled type. This evaporator as disclosed has a casing comprising a tank or boiler ll having a closure or valve plate member l2 about an opening in its side wall. It is preferred to have a supporting member I3 secured about the opening in the tank member to receive the fastening means H for securing the valve plate i2 in position. Suitable sealing gaskets are of course, inserted between the plate l2 and the supporting member l3. A manually actuated shut-off valve member (not shown) may be incorporated in the valve plate i2 at the point of entrance of the in let port l1. Surrounding this port II in the interior of the evaporator is a guiding member I6 for a needle valve, comprising a needle l8 adapted to open and close a small opening I! provided in member it which communicates with the inlet port II. The operation of the needle valve is controlled by a float ball 20 connected to the needle valve i8 by a pivoted bracket arm 2|. The operation and construction of this float controlled needle valve assembly is similar to that shown in the patent to R. G. Osborn, No. 1,556,708, issued October 13, 1925, and while being of slightly different design it is more or less conventional to those skilled in the art and therefore requires nofurther detailed description herein. Instead of locating this gaseous refrigerant outlet port leading from the evaporator in the valve plate i2 as shown in the Osborn patent referred to, the outlet port in the present disclosure is shown as being located in the top wall of the tank or casing II. The evaporator tank or casing II is surrounded on all sides by suitable insulating material 24 which material may, if desired, be enclosed in a casing 25 having closed openings for gaining access to the valve plate l2 and the connection leading from the outlet port of the evaporator. A conduit, coil or tank 28 may be disposed in the evaporator tank or casing ll below the liquid refrigerant maintained therein.

This conduit or coil 26 includes an inlet portion 21 and an outlet portion 28 for conveying a liquid such as water, beer or any other beverage through the coil 26 in thermal contact with and through the body of liquid refrigerant in the casing II to a suitable tap or faucet (not shown) adapted to be connected to the outlet 28.

It is preferred to have a collar 30 inserted in the outlet port of the evaporator and secured in any suitable manner to the top wall of the tank or casing I I. A manually actuated shut-off valve 3! is bolted or otherwise secured to the collar 30 and is adapted to be connected to the gaseous refrigerant suction return line leading from the evaporator to a compressor. A vertically disposed conduit 32 extends inwardly of the top wall of the tank or casing H and may be secured in any suitable manner to the shut-off valve fitting 3|, or to the walls of the aperture in collar 30. The conduit 32 may extend inwardly of the top wall of the evaporator any suitable distance and is herein disclosed ashaving its lower end disposed at substantially the level of liquid normally maintained in the evaporator. However, it is to be understood that the lower end of conduit 32 may, if desired, be disposed slightly below the normal liquid level maintained in the evaporator. The conduit 32 is,provided with vertically disposed intake portions or a plurality of gaseous refrigerant inlet openings 33 vertically spaced apart along the length of the conduit. An elongated float 34 is associated with the intake portions or inlet openings 33 and is preferably of slightly smaller diameter than the opening through the conduit 32 so as to permit locating the same within the conduit 32. Ears 35 provided on the lower end of conduit 32 (see Fig. 3) retain the float 34 in the conduit 32. The float 34 normally rests upon the ears 35 thus closing the opening in the bottom of conduit 32. Float 34 may be of any desired shape and is herein shown as being of sufficient elongation to permit its side walls to span several of the intake portions or inlet openings 33, for permitting the float to close the openings adjacent its walls. Liquid refrigerant fills the lower portion of the evaporator tank or boiler II to a predetermined height, determined by the calibration of the float ball 20. As this liquid refrigerant, which ispreferably sulphur dioxide, vaporizes and flows to or fills the upper part of the boiler or tank ll above the liquid refrigerant therein it is drawn through the gaseous refrigerant outlet port at the top of the evaporator.

Refrigerant vaporized or evaporated in the boiler or tank ll flows into conduit 32 through the intake portions or inlet openings 33 and passes through the conduit 32 to the valve 3| and thence to a refrigerant liquefying and condensing unit, a preferred form of which is illustrated diagrammatically in Fig. l. A compressor 42 which generally has a pumping action draws the evaporated refrigerant by suction through the outlet port of the evaporator and a conduit 43 connected to the valve fitting 3| to the crankcase of the compressor. The vaporized refrigerant is then compressed by the compressor and forwarded under pressure to a condenser 44 where it is liquefied in any suitable manner and deposited in a receiver 45 until it is required by the evaporator I 0, whence it passes through the conduit 46 to the inlet port H in the valve plate i2. The compressor 42 is preferably operated by a motor 48 operatively connected thereto through belt and pulley arrangements 49, SI and 52. Any of the wellknown controls may be employed for making and breaking an electric circuit to the motor 48 to start and stop operations thereof and consequently operations of the compressor 42. Such control may be of the thermostatic type actuated in response to thetemperature at the outlet of the water, beer or other beverage cooling coil 26, or it may be of the type which is operated in response to pressures within the refrigerating system such, for example, as a low pressure control as disclosed. However, either or both types of controls are now well-known in the refrigeration art and further explanation thereof herein is believed to be unnecessary.

A suitable quantity of lubricant such as oil is initially placed in the compressor 42 for the necessary lubrication of its moving parts. As previously explained some of this oil is can'ied along I with the refrigerant during omration of the compressor and passes through the condenser and receiver and eventually reaches the evaporator. It is necessary, however, to return this oil to the compressor. The problem not only involves the return of the oil itself but the return of oil before the oil blanket reaches a suflicient thickness in the liquid refrigerant in the evaporator to seriously affect the etllciency of the evaporator. Furthermore, it is also necessary to return the oil without returning any liquid refrigerant, as such .liquid refrigerant will cause frosting of the suction return conduit 43 thus causing a decrease in the efiiciency of the apparatus and also undes'rable pools or puddles of water on the floor. Accordingly this invention contemplates a pro vision of means for returning the oil and furthermore, insuring that no appreciable amount of liquid refrigerant will be drawn or sucked into the return conduit 43.

During normal evaporation of the liquid refrigerant in the evaporator the vaporized refrigerant has co-mingled therewith a quantity of oil, due to the aflinity of the oil for the refrigerant, and thus this vaporized refrigerant and oil carried thereby forms a somewhat heavy fog. This fog is drawn by suction of the compressor into the conduit 32 through the intake portions or inlet openings 33 and isreturned to the compressor. It will be noted that the body of liquid refrigerant is normally maintained by the float 20 at a substantially constant level below the bottom of the vertically dsposed outlet conduit 32 and under ordinary conditions this normal evaporation and the carrying therewith of oil in the form of a fog is ample to insure return of a sufficient amount of oil for properly lubricating the moving parts of the compressor and for maintaining a minimum quantity of oil 'in the evaporator. In an apparatus of the type disclosed it is obvious from the foregoing description that the liquid refrigerant level is suddenly increased above normal at certain periodic times during operation of the system. The liquid refrigerant level may at times rise to a height to cause the outlet conduit 32 to become partially submerged in the body of liquid refrigerant. However, by providing the float 34, which is adapted to float on eitherthe liquid refrigerant or oil in the evaporator, within the conduit 32, this float will rise with an increase above normal in the level of the body of liquid in the evaporator after the increased level reaches or partially submerges the conduit 32. The float thus closes some of the intake portions or inlet openings 33 immediately adjacent or above the abnormal refrigerant level and renders the lower portion of the suction conduit 32 ineffective. My

invention thereby completely eliminates the danger of withdrawing liquid refrigerant from the evaporator during an increase above normal in the level of the body of liquid refrigerant therein and insures that only gaseous refrigerant and oil will be conveyed to the compressor.

At the time very active ebullition or bubbling of the refrigerant occurs in the evaporator, such as when a considerable amount of water or beer is being circulated or caused to flow through the cooling coil means 26 in the evaporator, a great quantity of bubbles form beneath the level of liquid refrigerant in the evaporator thus causing the level to rise suddenly to a height above that normally maintained therein by the liquidrefrigerant inlet float 20. The float 34 of my improved device being lighter than either the oil or liquid refrigerant is caused to move upwardly in the conduit 32 upon being engaged by or floated upon the level of the foam-like mass of liquid refrigerant and oil in the evaporator. Float 34 follows the level of the body of liquid in the evaporator when this level attains a height suilicient to permit liquid refrigerant to enter the conduit 33 and closes ofl some of the intake portions or inlet openings 33 in the conduit 32 to prevent liquid refrigerant from being sucked into the conduit 32 and returned to the compressor. It is to be understood that only the intake portions or inlet openings 33 located above the position of float M are effective for drawing or sucking refrigerant gas and oil into the gaseous refrigerant suction line of the system. Therefore the effective intake portions of conduit 32 are decreased when the float is raised from its lower position and this causes increased velocity of .flow of refrigerant gas through the remaining open intake portions which more readily draws oil into the conduit. The expanded body of liquid or-foam-like mass of liquid in the evaporator and the raised position of the float 34 is clearly illustrated in Fig. 2 of the drawings. It is apparent therefore that .the effective intake portions or inlet openings 33 in the outlet conduit 32 are maintained in spaced relation to the level of the body of liquid in the evaporator and particularly at times when the level attains a heightsuflicient to submerge a portion of the outlet conduit 32 and its intake portions in the body of liquid.

While I amraware that oil return devices and various arrangements of outlet conduits or ducts extending into evaporators, employed in installations wherein heat is gradually given up to or absorbed by refrigerant in the evaporators, are not broadly new none of such devices or outlet arrangements known to me are or have been found to be entirely satisfactoryor suitable for use in an apparatus of the type disclosed. :In the use of known oil return devices or arrangements of gaseous refrigerant outlet conduits in an evaporator wherein a water or beer cooling coil is sub-' merged in the liquid refrigerant the herein described rise of the level of the liquid refrigerant in the evaporator causes liquid refrigerant to.

enter the gaseous refrigerant suction line leading to the compressor. -My improved arrangement or apparatus therefore overcomes problems present in a system as disclosed, which problems cannot be overcome by the use of prior devices or structural arrangements, and therefore accomplishes eificient return of oil from the evaporator to the compressor during normal operation of the refrigerating system, while at the same time insuring that no appreciable amount of liquid refrigerant will enter the gaseous refrigerant suction line of the system during temporary abnormal conditions in the evaporator.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, a compressor, a gaseous refrigerant suction line communicating with said compremor and with said evaporator, said suction line including vertically disposed intake portions exposed to the interior of the evaporator, and means for closing some of said suction line intake portions automatically in response to an increase above normal in the level of the body of liquid in the evaporator.

2. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction. line including vertically disposed intake portions exposed to the interior of the evaporator, and means for closing some of said suction line intake portions automatically in response to conditions within the evaporator.

3. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including vertically disposed intake portions exposed to the interior of the evaporator, and means for closing some of said suction line intake portions automatically in response to an increase above normal in the level of the body of liquid in the evaporator.

4. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including vertically disposed intake portions exposed to the interior of the evaporator, and a float associated with said intake portions, said float being actuated automatically in response to an increase above normal in the level of the body of liquid in the evaporator to close some of said intakeportions.

5. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including vertically disposed intake nortions exposed to the interior of the evaporator, and a float associated with said intake portions, said float being actuated automatically in response to an increase above normal in the level of the body of liquid in the evaporator to close some of said intake portions.

6. A refrigerating system comprising in combination, ,an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including a vertically disposed conduit portion extending inwardly of the top wall of the evaporator and having a plurality of vertically disposed intake portions exposed to the interior thereof, and a float associated with said intake portions and located within said vertical conduit portion of said suction line, said float being actuated automatically in response to an increase above normal in the level of the body of liquid in the evaporator to close some of said intake portions.

7. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, a float valve mechanism for maintaining the body of liquid refrigerant at a normal substantially constant level, means submerged in the liquid refrigerant in said evaporator for directing a liquid to be cooled therethrough, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including a vertically disposed conduit portion extending inwardly of the top wall of the evaporator and having a plurality of vertically disposed intake portions exposed to the interior thereof, and a float associated with said intake portions and located within said vertical conduit portion of said suction line, said float being actuated, automatically in response to an increase above normal in the level of the body of liquid in the evaporator to close some of said intake portions.

8. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, a compressor, a gaseous refrigerant suction line communicating with said compressor and. with said .evaporator, said suction line including a plurality of vertically spaced apart horizontally disposed intake portions exposed to the interior of the evaporator, and means for closing some of said suction line intake portions automatically in response to an increase above normal in the level of the body of liquid in said evaporator.

9. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including a plurality of vertically spaced apart horizontally disposed intake portions exposed to the interior of the evaporator, and means for closing some of said suction line intake portions automatically in response to an increase above normal in the level of the body of liquid in said evaporator.

10. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator, a compresson'a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including a plurality of vertically spaced apart horizontally disposed intake portions exposed to the interior of the evaporator, and a float actuated automatically in response to an increase above normal in the level of the body of liquid in said evaporator for closing some of said suction line intake portions.

11. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for maintaining the body of liquid refrigerant at a normal substantially constant level, a compressor, a gaseous refrigerant suction line communicating with said compressor and with said evaporator, said suction line including vertically disposed intake portions exposed to the interior of the evaporator above the liquid level therein. and means for closing at least one of said suction line intake portions automatically in response to an increase above normal in the level of the body of liquid in the evaporator.

' JESSE G. IGNG.

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