US2084755A - Refrigerant distributor - Google Patents

Description

June 1937- H. s. YOUNG, JR

REFRIGERANT DISTRIBUTOR Filed May 3, 1955 INVENTOR. /7 FN/QY 5. You/v6, J

A TTORNEY.

Patented June 22, 1937 UNITED STATES PATENT OFFICE mesne assignments,

to Carrier Corporation,

Newark, N. .L, a corporation of Delaware Application May 3, 1935, Serial No. 19,741

12 Claims.

This invention relates to refrigeration apparatus and more particularly, to a method of and means for distributing refrigerant to a plurality of evaporator tubes.

.5 Itis common practice in the refrigerating art to utilize evaporators comprising a plurality of circuits. In order that such evaporators may function-most efliciently, it is necessary that refrigerant liquid be supplied to each of the circults at an equal rate. This is particularly true in the case of the so-called flash evaporators,

in which refrigerant is passed only once through the evaporator tubes before proceeding to the compressor.

The supply of refrigerant to an evaporator circuit is dependent upon conditions prevailing at the orifice serving the circuit. Thus, in order that each of a plurality of evaporator circuits may be supplied with equal quantities of refrigerant liquid and gas from a common source, it is essential that the refrigerant liquid and gas be supplied under substantially identical conditions to each of the orifices serving the individual circuits. In practice, equality of conditions at each of the orifices is diflicult of attainment, because refrigerant gas and liquid enter at high velocity the header from which the individual orifices are fed. The liquid in the header is thus agitated, the resultant turbulence and wave motion causing inequalities in the liquid level at the orifices. When the refrigerant gas and liquid enter the header as a mixture, turbulence and wave motion are greater than when the gas and liquid are separated. Also, the liquid head on each of the orifices will not be the same unless the header is carefully placed and maintained in its intended position. It is apparent that when the header is installed on vehicles, such as railroad cars, the problem of maintaining a uniform liquid level on each of the orifices becomes particularly difiicult.

Further, it is generally the case that the evaporator circuits do not present equal resistance to the flow of refrigerant therethrough, due to dents, imperfections in soldering or welding, the accumulation of sediment or the like. These inequalities of resistance tend to cause unequal distribution of the refrigerant.

Moreover, distributors heretofore available have been limited in their use to applications in which they might remain fixed in position, feeding either a horizontal or a vertical evaporator.

The general object of the invention is to provide a method of and means for distributing re- 55 frigerant to each of a. plurality of evaporator tubes, whereby each of the evaporator tubes will receive an equal quantity of refrigerant liquid.

Another object of the invention is to supply equal quantities of refrigerant liquid to' each of a plurality of evaporator tubes by forming a sheet of refrigerant liquid and causing said sheet to flow over openings in communication with the evaporator tubes, substantially independently of the force of gravity.

Another object of the invention is to utilize the centrifugal force developed by a rapidly rotating body of fluid to form said liquid sheet.

Another object of the invention is to cause refrigerant liquid to advance lengthwise of a casing in a sheet, revolving about the axis of said casing, adjacent the inner surface of said casing.

Another object of the invention is to provide a novel method of separating gas and liquid by centrifugal action.

Another object of the invention is to provide a method of and means for distributing refrigerant to each of a plurality of evaporator circuits, whereby each of the circuits will receive desired quantities of refrigerant liquid.

Another object of the invention is to provide a refrigerant distributor which is relatively simple, inexpensive, compact and highly efficient.

A feature of the invention resides in the provision of a casing, circular in cross-section, having a plurality of openings in said casing, each of said openings being in communication with an evaporator tube.

Another feature of the invention resides in the provision of means whereby refrigerant liquid is introduced into the casing at relatively high velocity and is caused tc flow around the inner surface of the casing in a sheet advancing lengthwise of the casing.

Another feature of the invention resides in the provision of damping means to check the flow of refrigerant liquid lengthwise of the casing.

Another feature of the invention resides in the provision of a casing the body portion of which consists of a plurality of hollow truncated conical sections.

Another feature of the invention resides in the provision of a nozzle in the refrigerant supply line, on the evaporator side of the expansion valve, said nozzle being adapted to discharge refrigerant into the casing at relatively high velocity tangentially of the inner surface thereof.

Another feature of the invention resides in the introduction of refrigerant at a point along the axis of the casing, and causing the refrigerant to revolve about said axis while advancing lengthwise of the casing.

Another feature of the invention resides in the provision of a bend in the refrigerant supply line between the expansion valve and the nozzle.

Another feature of the invention resides in discharging refrigerant toward the discharge end of the distributor casing from a tilted nozzle.

Other objects and features of the invention will be apparent from the. following description, to be read in connection with the accompanying drawing, in which:

Fig. 1 is an elevational view, partly in section, of one form of the invention, illustrative of the manner in which the sheet of liquid refrigerant is built up;

Fig. 2 is a plan view of the .embodiment of Fig. 1, showing the tubes which provide communication between the distributor openings and the evaporator, and the bent refrigerant supply line;

Fig. 3 illustrates an embodiment of the invention in which the sides of the casing comprise a plurality of hollow, truncated conical sections;

Fig. 4 illustrates the use of damper rings and a tilted nozzle, in combination with a cylindrical casing; and

Fig. 5 illustrates another form of the invention in which refrigerant is introduced into the casing through one of the ends thereof.

Referring now to the drawing, similar designations referring to similar parts, the numeral I0 designates generally a casing comprising a headpiece II, at the discharge end of the casing, an end I2, and a cylindrical body portion I3. In the headpiece I I are formed a plurality of open ings I4, preferably equally spaced around the casing. As shown, there are eight of these openings I4, but it is to be understood. that any number may be utilized in accordance with engineering expediency. Tubes I5 lead from the openings I4 to the tubes of the evaporator (not shown), and provide communication therebetween. Nozzle I6, in refrigerant supply pipe I1 on the evaporator side of expansion valve I8, is positioned at the end of easing I0 opposite headpiece and is adapted to discharge refrigerant into the casing tangentially of the inner surface thereof. In the preferred arrangement, as shown in Fig. 2, no part of nozzle I6 protrudes within the casing.

In operation, a mixture of refrigerant liquid and flash vapor is fed to the nozzle it through refrigerant supply pipe I1. This mixture is discharged at relatively high velocity through nozzle I6. The refrigerant liquid circles about the casing and, because of the centrifugal force developed by reason of its high velocity, flattens out into a smooth sheet, as shown at I9 in Fig. 1. The gaseous refrigerant rises through the center of the casing. As the sheet of refrigerant liquid passes over the openings I4, liquid refrigerant enters thereinto due to centrifugal force, the suction of the compressor, and the action of gas entering the tubes. Since the refrigerant liquid passes over each of the openings III in equal quantities, it will be apparent that equal quantities of refrigerant liquid will be drawn into each evaporator tube.

When a partial restriction occurs in an evaporator tube, the quantity of gaseous refrigerant flowing therethrough is diminished to equalize the pressure drop with the other tubes. Unless the restriction be of a major order, liquid refrigerant continues to flow into each of the evaporator tubes at an equal and undiminished rate,

since the flow of liquid is equally proportioned in the header. Thus, it will be seen that applicant provides for the distribution of an equal quantity of refrigerant liquid to each of a plurality of evaporator tubes, notwithstanding partial restrictions in one or more of the tubes. Since it is the liquid refrigerant and not the gaseous refrigerant which efiects cooling, it follows that, in applicant's system, each evaporator tube does a substantially uniform amount of refrigerating work.

Since the centrifugal force developed in applicants distributor is very great, and may be of the order of several hundred times the force of gravity, the distributor may be used in horizontal or vertical positions, as desired, with substantially no difference in operating characteristics, and is suitable for universal application.

To impart to the refrigerant liquid a velocity component lengthwise of the casing, in "order that the sheet of liquid may clear the nozzle as it sweeps around the inner surfaceof the casing, applicant utilizes a casing of frusto-conical design. To prevent too rapidflow lengthwise of I the casing, in such case, in order that there may be a sufiicient time interval for the refrigerant liquid to form a smooth sheet, applicant provides suitable damping means. As illustrated in Fig. 3, the sides of easing I 0 consist of truncated conical sections I30. and -I3b. Refrigerant liquid, introduced through nozzle I6, circles the inner surface of casing section I3a and advances lengthwise of the casing toward the opening I4, clearing the nozzle. Ledge 2t, connecting the lower edge of easing section I3b with the upper edge of easing section I311, provides an impediment to the lengthwise flow of the refrigerant fluid, retarding such flow sufiiciently to insure the flow of liquid refrigerant over openings It in 'a smooth sheet. Though a single ledge 20 is shown, it is to be understood that two or more of such ledges may be provided, as desired.-

In the embodiment illustrated in Fig. 4, in which a cylindrical casing is employed, the nozzle I6 is 'tilted slightly toward the outlet end of the casing, in order that refrigerant liquid discharged from the nozzle may have a velocity component lengthwise of the casing, thus to clear the nozzle. Rings 2I, formed on the inner surface of the easing, serve to dampen the lengthwise flow of refrigerant liquid, in much the same fashion as the ledge 20 of Fig. 3, and thus insure an even, smooth flow of refrigerant liquid'over each of the openings M in equal quantities.

Fig. 5 illustrates another form of the invention, in which refrigerant is introduced into the casing through one of the ends thereof, instead of piece II, and the upper side section I3b, are similar in all respects to the corresponding sections illustrated in Fig. 3. Section I3c, engaging I3b to form ledge 20, comprises a cone, the apex of which is truncated by connection to supply pipe 22. A deflector member 23, is positioned in the mouth of section I30, and provides a spiral path for refrigerant entering the casing through supply pipe 22. Thus, refrigerant liquid discharged into the casing through the supply pipe 22 and the deflector member 23 revolves about the axis of the casing, in a sheet formed on the inner surface of the casing, and travels lengthwise thereof. As in the case of the embodiments of the invention above described, the refri erant liquid flows over the openings ll in a smooth sheet, and is drawn therethrough to each of the evaporator tubes in equal quantities.

As illustrated in Fig. 2, applicant prefers to provide a bend in the supply pipe i'I, between the expansion valve [8 and the nozzle I6. This bend is of substantial assistance in separating gaseous and liquid refrigerant, the liquid being thrown to the outer side of the supply pipe at the bend. Use of the bend improves the operating efliciency of the distributor.

In the foregoing, applicant's device has been described as supplying equal quantities of refrigerant to each evaporator circuit. In some cases, as where there is an unequal distribution of load on the evaporator circuits, correspondingly unequal distribution of refrigerant may be desirable. By utilizing openings i l of varying sizes, uniformly or irregularly spaced around the casing, any desired distribution may be attained.

It will be apparent to those skilled in the art that many changes may be made in the invention without departing from the spirit and scope of the invention. Accordingly, it is intended that the above description and the accompanying drawing be regarded as illustrative only, and not in a limiting sense.

I claim:

1. In a refrigerant distributor, a casing, said casing being circular in cross-section, a plurality of discharge openings in said casing, means for supplying refrigerant to the casing and for causing the refrigerant to flow at high velocity around the inner surface of the casing in the form of a smooth sheet, refrigerant being drawn from said sheet through said openings.

2. In a refrigerant distributor, a casing, said casing being circular in cross-section, means for introducing refrigerant liquid within the casing and for causing said refrigerant liquid to revolve at high velocity around the axis of said casing in the form of a sheet, and outlet means in said casing for drawing refrigerant liquid from the sheet.

3. In a refrigerant distributor, a casing, said casing being circular in cross-section, means for supplying refrigerant to said casing tangentially of the inner surface of said casing to form a rotating film of refrigerant proximate the inner surface of said casing, and a plurality of circumferentially arranged outlet openings in said casing, refrigerant from said film being withdrawn through said openings.

4. In an apparatus of the character described, a casing, said casing being circular in cross-section, a plurality of outlet openings in said casing, and means including a refrigerant supply nozzle for supplying refrigerant gas and refrigerant liquid to said casing at high velocity and for causing the refrigerant liquid to assume the form of a rotating sheet, refrigerant-from said sheet being drawn at a substantially constant rate through each of said outlet openings.

5. In a refrigerant distributor, a casing, said casing being circular in cross-section, a plurality of outlet openings proximate one end of said casing, and means proximate the other end of said casing for discharging refrigerant into said casing tangentially of the inner surface thereof, the diameter of said casing varying along the axis of said casing.

6. In a refrigerant distributor, a casing, the sides of said casing including a plurality of hollow truncated conical sections and a ledge connecting said sections, a plurality of outlet openings in said casing, and means for introducing refrigerant into said casing at high velocity and for causing said refrigerant to revolve about the axis of said casing adjacent the inner surface thereof.

7. In a refrigerant distributor, a casing, a plurality of outlet openings in said casing, means for introducing refrigerant into said casing. means for causing said refrigerant to revolve about the axis of said casing adjacent the inner surface of said casing, thereby to form ,a sheet and to advance lengthwise of said casing, and means to impede the flow of refrigerant lengthwise of the casing.

8. In a refrigerant distributor, a casing, a

plurality of outlet openings in said casing, and a nozzle for supplying refrigerant to the casing, said nozzle being adapted to discharge refrigerant tangentially of the inner surface of said casing and toward said outlet openings.

9. In a refrigerant distributor, a casing, the sides of said casing comprising a plurality of sections, at least one of said sections being frustoconical in shape, a ledge connecting adjacent of said sections, a plurality of outlet openings in said casing and means for discharging refrigerant into said casing and for causing said refrigerant to revolve about the axis of said casing adjacent the inner surface thereof.

10. In a refrigerant distributor, a casing, a plurality of refrigerant outlets in said casing, means for introducing refrigerant liquid into said casing, and means for causing said refrigerant liquid to revolve about the axis of said casing adjacent the inner surface thereof in the form of a continuous sheet, said outlets being in the path of said sheet.

11. In a refrigerant distributor, a casing, a plurality of refrigerant outlet openings irregularly spaced around said casing, means for introducing refrigerant gas and refrigerant liquid into said casing, and. means for causing said refrigerant liquid to revolve about the axis of said casing adjacent the inner surface thereof in a continuous sheet passing over said openings.

12. In a refrigerant distributor, a casing, a plurality of refrigerant outlet openings in said casing, said openings being of varying size, means for introducing refrigerant liquid into said casing and means for causing said refrigerant liquid to revolve about the axis of said casing adjacent the inner surface thereof in the form of a continuous sheet passing over said openings.

HENRY B. YOUNG. JR.

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