US2127101A - Refrigerating apparatus - Google Patents

Description

Aug. 16, 1938. QG.VF.ZELLHOIEFER ,1 2,127,101

7 REFRIGERATING APPARATUS Filed March 29, 1937 INVENTOK 61 E/VN F. 251. 4 flail-ER W W ATTORNEY.

UNITED STATES REFRIGERATING mamirus Glenn F. Zellhoefer, 8100 Williams Oil-O-Matic H n, 111., assignor to ting Corporation,

Bloomington, Ill.-, a corporation of Illinois I Application March 29, 1937, Serial No. 133,510.;

a 1 Claim. (01. 02-119) This invention relates to improvements in thev absorption type of refrigerating apparatus in which a solvent such as dimethyl ether of tetraethylene glycol, or asimilar type of chemical forms a solution with a refrigerant such as dichloromonofluoromethane or a similar type of chemical in an absorber, the solution passed into a heater or still wherein the refrigerant is released or boiled off the solution and delivered to a condenser, collected as a liquid in a receiver, and delivered to an evaporator from which thegaseous refrigerant is returned to the absorber while the solvent of the solution from which the refrigerant has been separated in the heater returns to the absorber. This invention relates more particularly to the method and means, when the evaporator employed is of' the flooded type, of returning from the evaporator such particles of the solvent which invariably are carried over with the gaseous refrigerant into the evaporator.

The single figure of the drawing is a'diagrammatical representation in elevation of an evaporator of-the flooded type with the connections to the condenser or receiver and absorber such as employed in an absorption type of refrigerating apparatus as described above. Other elements ofsuch a system do not form a part of this invention and, therefore, it is not thought necessary to illustratethem. The evaporator illustrated is employed for the purpose of cooling water or brine, ,as-lessheat transfer surface is required in this method of cooling than in the method using a dry expansion type of evaporator.

In an absorption refrigeration apparatus or unit using dimethyl ether of tetraethylene glycol as a solvent, and dichloromonofluoromethane as the refrigerant, for an example, which operates at a temperature of 235 F. in the heater, and,

condenser to the low side. When the refrigerant vaporizes in a flooded type of evaporator, essen;

. tially all the solvent carried over remains in the evaporator. In due time, the unit becomes inoperative due to this accumulation of solvent, unless provision is made forthe return of thesolvent I from the evaporator to the absorber.

This difllculty is not encountered in a dry expansion type of evaporator because the velocity of the refrigerant vapors carries the solvent through the evaporator back to the absorber even though there is a considerable rise between the point at which vaporization starts in the evaporator and the point of inlet to the absorber.

The purpose of this invention is to provide means-cf returning the solvent from the flooded evaporator rapidly enough to maintain satisfac tory concentration of refrigerant in the evaporator.

Referring to the above example, wherethe liquid dichloromonofluoromethane in the condenser of this type of absorption refrigeration unit is F. and the saturated refrigerant temperature in the evaporator is 40 F., the refrigeration required to cool the liqu'idrefrigerant from the temperature in the condenser to the evaporator temperature of 40 F. is approximately. 14 B. t. u.s per pound, or approximately 13.6% of the total refrigeration effect produced in the evaporator by the vaporization of one pound of refrigerant.

, This cooling of the refrigerant may be effected within the evaporator or may be effected by precooling the refrigerant before it enters the evaporator. In pre-coollng the liquid refrigerant from the condenser by the vaporization of refrigerant a fiow'of refrigerant from the evaporator equivalent to approximately 10% of the flow of refrigerant from the condenser to the evaporator.

Consequently, if the refrigerant from the condenser has 0.1% solvent and the refrigerant taken from the evaporator for pre-cooling theliq'uid denser when the rate of flow of refrigerant from the evaporator to the pre-cooler is 10% of the rate of flow from the condenser to the. evaporator.

Since concentrationsof solvent in the refrigerant of as much as 3% or.4% is not objectionable for operation of the floodedlow side, it follows that it is not necessary to'use more than essary to pre-cool the liquid refrigerant to the evaporator temperature. It is, therefore, contemplated in accordance with this invention to feed the refrigerant from the evaporator through a fixed orifice into a pipe connected to the absorberand around which is a concentric pipe through which flows the liquid refrigerant from PAT OFFICE 'takenfrom the evaporaton'it is possible to have one-third to one-fourth of the refrigerant necthe condenser to the evaporator, in a counterflow is made to the accompanying drawing which illustra'tes a preferred embodiment of this invention, with the understanding that-detail changes may be made without departing from the scope thereof.

The evaporator. E indicated in longitudinal' vertical central section is preferably in the form of a cylinder provided with convex end closures 2 and 3. A vertical partition 4 separates the end closure 2 from the body of the evaporator. A float valve'chamber I is supported on the opposite end closure 3 with a float-operated valve to maintain the liquid level, as-shown by the dotted lines, in the evaporator and is connected by pipes 8 and I to the upper and lower sides of the evaporator respectively.

The pipe Heads the fluid to be cooled into the top of the space between the end closure 2 and partition 4. The partition 4 supports the ends of a row of horizontal pipes 9 which extend to a point adJacent the opposite end closure 3 and are then bent to return in parallel spaced-apart relation to the partition. The pipes 9,, are arranged to extend normally above the level of the liquid refrigerant in the evaporator, as sho by the dotted lines, with the respective ends opening through the partition 4 into the space between the end closure 2 and the partition I and each is preferably provided with thin equally-'- spaeed-apart radiationplates or flns l 0, as shown. A horizontal partition II is arranged between the end closure iand the partition between the openings of the upper and lower rows of the pipes 9, whereby the liquid from the pipe 8 is caused tocirculatethrough the pipes l in the gaseousv refrigerant. It is preferable to arrange two similar rows of pipes l2 and 'Il below the pipes 9 with partitions I4 and II similar to partition ll between their respective openinas irito the chamber between the end closure 2 and the partition 4, whereby the fluid is caused to circulate through the liquid refrigerant wi in.the evaporator E. .The space below the pa tition I is connected to a pipe IQ for conducting the cooled fluid to its destination. A

A pipe I! leads the liquid refrigerant from the receiver or condenser of the .apparatus, not shown, to the float chamber 5 and a pipe l8 leadsthe gaseous refrigerant evaporated at the liquid level in the evaporator to the absorber of th apparatus, not shown.

This inventio'mcontemplates the prevention of such solvent as is invariably carried over from the heater or still with the refrigerant into the evaporator from collectingthere'in and eventually rendering the evaporator inoperative by providing ,at-the bottom of -the evaporator a small oriflce' or bleeder ls preferably of adjustable size, which opens into a pipe 20 leading to the absorber ofthe apparatus, not shown. The pipe 20 is arranged in the form of agooseneck It ,below the under-side of the evaporator and may be termed a semi-flooded container, as

the refrigerant with particles of solvent enters this portion through the orifices".

The size of semi-flooded pipe must be small enough tocarry proper velocities of gaseous refrigerant sons to sweep, the solvent liberated i in pipe 2| back to the absorber; also sufllciently large to provide for the delivery of the required amount of the refrigerant-solvent mixture to maintain satisfactory equilibrium of solvent and pipe.

The warm liquid refrigerant from the condenser efl'ects vaporization of the refrigerant in pipe 20 affording a quite definite and controlled amount of heat for this purpose and at the same time conserving the refrigeration effect.

This invention contemplates providing an enlargement 22 oi. the pipe I! through which the pipe 20 passes from a point adjacent the bottom of the evaporator, a sufficient distance to produce the desired effect. The liquid refrigerant is conducted from the enlarged portion 22 of the pipe. I! adjacent the evaporator by a pipe 23 leading to the float chamber 5, and the refrigerant is conducted from the float chamber to evaporator E by pipe I. This same type of device may be used in conjunction with a compressor to-return oil from a flooded lo w side'to the crank case of a com-- What I claim is:

In an absorption refrigerating apparatus including a horizontal cylindrical evaporator of the flooded type provided with a float valve, for

controlling the level of the liquid refrigerant therein, within a chamber, a pipe for leading the liquid refrigerant from the condenser to the float valve chamber, a pipe for leading the gaseous and a bleeder oriflce opening through the bottom of the evaporator into a pipe depending therefrom to form a liquid trap and that isto then lead to the absorber, said latter pipe on leaving the evaporator through an enlarged substantial section 01 the pipe leading the liquid refrigerant to the float valve chamber, the size of the bleeder and the length of said enlarged section so related that the solvent carried over from the heater with the gaseous refrigerant and passing through the float valve is removed from the bottom of the evaporator with a sufllcient portion of the liquid refrigerant to be volatilized in passing through the said enlarged section and the solvent separated therefrom swept into the absorber.

, refrigerant from the evaporator .to the absorber,

'GLENN r. ZELLHOEFER.

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