US2234498A - Refrigeration unit - Google Patents

Description

March 11, 1941. MAFFET 2,234,498

REFRIGERATION UNIT Filed July 31, 1939 2 Sheets-Sheet 2 fifllllllllllllllll INVENTOR.

PAUL h. MAI-F57.

BY %ATTORNEY.

Patented Mar. 11, 1941 uses STATE OFFICE 4 Claims.

This invention relates to a refrigeration unit and more particularly to adevice which will replace the usual float valve thermostatic expansion valve of the typical refrigerating equipment.

In the usual mechanical refrigerating system a float valve is employed to control the flow of refrigerant liquid to the evaporator or cooling unit. A thermostatically controlled expansion valve is also employed to control the flow of refrigerant. Both of these valves are subjected in both their various moving parts and in their valve seats which require frequent repairs and replacements. The float valve is also objectionable in that its operation is not uniform, that is, it will remain closed while the liquid refrigerant is collecting until it rises over the top of the float. The float then suddenly releases the valve to allow a large flow of refrigerant which will continue until the refrigerant passes out when'it suddenly closes. This results in an uneven, fluctuating flow of refrigerant and a wide variance of pressure differential.

The principal object of this invention is to eliminate the float valve and the thermostatic expansion valve with their attendant maintenance costs and'their non-uniform operation; to provide means which will maintain a uniform pressure differential between the high and the low pressure zones of the system throughout the entire range of operation; and in which all wearing and moving parts will be eliminated so that it can operatecontinuously and indefinitely without requiring repairs or replacements.

Other objects of the invention are to provide a combination expansion valve, receiver, and condensing unit for refrigerating systems which will lower operating costs, which will operate on lower head pressure, which will require less condensing coil surface, and in which all wearing parts will be eliminated.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efficiency. These will become more apparent from the following description. I

In the following detailed description of the invention reference is had to the accompanying drawings which form a part hereof. Like numeralsrefer to like parts in all views of the drawings and throughout the description.

In the drawings:

Fig. 1 is a cycle diagram of a typical refrigerating system illustrating the improved unit in place therein.

Fig, 2 is an enlarged vertical section through the improved unit.-

Fig. 3 is a vertical cross section therethrough, taken on the line 3-3, Fig. 2.

Fig. 4 is a horizontal section, taken on the line 5 9-4, Fig. 2.

In the cycle diagram of Fig. 1, the typical elements of a refrigerating system are designated by numeral as follows; electric motor ill, compresser H, condenser l2, evaporator orcooler I3 10 andreceiver 39. This invention is designed to be placed in the line between thereceiver 39 and the evaporator I 3.

The invention comprises a horizontal housing It, sealed to and supporting a vertical housing i5. The housing I5 is entirely sealed but access may be obtained to the housing l4 through a removable head plate 5 which is secured thereon by means of suitable clamp bolts H. The vertical housing l5 contains a heat exchange coil l8 spirally wrapped about its inner surface. One extremity of this coil is connected to a tube l9 leading from thereceiver 39. The other extremity of the coil is connected with a by-pass tube 20 communicating through the head plate l6 of the housing I4.

The interior of the housing l5 communicates at its top to a suction line 2| leading to the intake of the compressor II, and communicates adjacent-its bottom with agas line 22 leading from the evaporator l3. By this arrangement, the entire interior of the housing I5 is constantly filled with cold, low-pressure gas.

The by-pass line 20 leads to a screen fitting 23 supporting asuitable screen 24. Thescreen fitting 23 is threaded into anexpansion valve coupling 25 containing anorifice member 26 having a restricted flow oriflce. The orifice member discharges into aninjector tube 21 extending through the head IS. Theinjector tube 21 terminates within a suction sleeve 28 which is supported from the head l6 by means of an outer supporting tube 29 provided with perforations 30. The supporting tube 29 carries a fitting 3! at its inward extremity from which atrap coil 32 is supported.

A quantity offluid 33, such as mercury or other fluid agent of greater specific gravity or density than the refrigerant, suiflcient to partially cover thecoil 32, is contained within the housing I 4. Thefluid 33 is freeto flow through the perforations 30 into the interior of the tubes 28 and 29 and into the fitting 3|. The extremity of thetrap coil 32, shown at 34, opens to the interior of the housing l4 adjacent the bottom thereof. 5

Agooseneck trap 33 extends through the top of the housing ll through the latter and into the housing ll to a point below the surface of the fluid therein. The gooseneck is perforated, as shown at 33, at a point above the normal fluid level in the housing It. Adrain tube 31 drains the trap of the gooseneck back into the body of fiuidln the housing II. Aliquid refrigerant line 33 extends from thegooseneck 33 to the evaporator l3.

Operation Let us start the cycle at the compresser II. The compresser compresses the refrigerant gas to a liquid. This liquid is first cooled in the condenser I2 from whence it flows through the coil ii. The latter is immersed in cold, low pressure gas so that a second condensation or chilling takes place therein. The cool liquid now flows to theexpansion oriflce member 23 from which it expands to a wet gas in theinjector tube 21. The velocity of the refrigerant discharging from thetube 21 creates a suction in thesuction tube 23 to draw thefluid 33 from the container ll. This fluid and the refrigerant flows through thetrap coil 32 chilling thefluid 33. From the extremity of the coil, the refrigerant bubbles up through thefluid 33 and flows into thegooseneck 35 where a portion of the fluid being carried by the cold expanded gas is dropped and flows back to the container I! through thedrain tube 31. The refrigerant gas will collect at the top of the housing I where it will rapidly condense and fall to the surface of thefluid 33. From thence it will flow through theperforations 36 into the flow line. The cold refrigerant gas intermixed with the remainder of thefluid 33 then flows through theline 33 to the evaporator i3 where the major expansion, evaporation and cooling takes place. The expanded gas then returns through theline 22 to the housing i where it absorbs heat from the coil l3 and thence flows back to the compresser H.

As long as'the unit and the evaporator are warm, the viscosity or density of thefluid 33 is low and the gas can readily flow through the fluid and can readily draw it into the suction tube. As the evaporator gets colder, however, the gas returning therefrom has a lower temperature which acts to lower the temperature of the refrigerant flowing through thecoil 32. This results in lowering the temperature of thefluid 33 so that the latter becomes more dense and it is more difficult for the gas to pass therethrough. Thus the flow of the refrigerant to the evaporator is increasingly resisted as the temperature thereof drops and the pressure in the receiver gradually builds up so as to maintain a uniform pressure differential between the liquid refrigerant from the compressor and the gas in the evaporator.

As the temperature rises in the evaporator, the temperature of the gas returning therefrom will correspondingly rise. This will raise the temperature of thefluid 33 to decrease its density and to allow more refrigerant to flow to the evaporator.

It wil1 be noted that the acceleration and deceleration changes are very slow and very gradual so that the desired temperature can be accurately maintained without the violent fluctuations of a float or thermostatic valve. The flow is at all times accurately and minutely proportional to the variations of temperature in the system. This control does depend upon the amount of refrigerant present and is accomplished without the use of valves or other moving parts.

It is possible to approximate the results accomplished by this invention by connecting theline 33 directly to theextremity 33 of thecoil 32 so that the refrigerant will not come in actual contact with the fluid 33. The refrigerant liquid will then collect in the lower portions of the turns of the coil and act to resist the flow of refrigerant therethrough in accordance with the density produced therein by the chilling effect of the fluid 33.

While a speciflc form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

l. Means for controlling the flow of refrigerant to the evaporator of a refrigerating system comprising: a fluid container; a fluid of greater density than the refrigerant in said container; a refrigerant coil partially submerged in said fluid; means for conducting refrigerant to said coil, said coil discharging below the surface of the fluid in said container; and means for con ducting the refrigerant from above the fluid to said evaporator.

2. Means for controlling the flow of refrigerant to the evaporator of a refrigerating system comprising: a fluid container; a fluid of greater density than the refrigerant in said container; a pressure jet for introducing refrigerant into said container below the fluid level therein; a sleeve surrounding the pressure jet and opening to the fluid so that the pressure of said jet will draw the fluid into the sleeve to intermix the fluid and the refrigerant; and means for conducting the refrigerant from above the normal fluid level to said evaporator.

3. Means for controlling the flow of refrigerant to the evaporator of a refrigerating system comprising: a fluid container; a fluid of greater density than the refrigerant in said container; a pressure let for introducing refrigerant into said container below the fluid level therein; a sleeve surrounding the pressure jet and opening to the fluid so that the pressure of said jet will draw the fluid into the sleeve to intermix the fluid and the refrigerant; a coil immersed in said fluid for receiving the intermixed refrigerant and fluid, said coil discharging into said container; and means for conducting the refrigerant from said container to said evaporator.

4. Means for controlling the flow of refrigerant to the evaporator of a refrigerating system comprising: a fluid container; a fluid of greater density than the refrigerant in said container; a pressure jet for introducing refrigerant into said container below the fluid level therein; a sleeve surrounding the pressure jet and opening to the fluid so that the pressure of said jet will draw the fluid into the sleeve to intermix the fluid and the refrigerant; a coil immersed in said fluid for receiving the intermixed refrigerant and fluid, said coil discharging into said container; a trap for separating the fluid from said refrigerant; means for conducting the refrigerant from said container to said evaporator; and a trap for separating the fluid from the refrigerant flowing to said conduit.

PAUL H. MAFF'ET.

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