US2081128A - Automatic defroster and moisture control for mechanical refrigerators - Google Patents

Description

May 18, 1937. A. s. VOLPlN AUTOMATIC DEFROSTEH AND MOISTURE CONTROL FOR MECHANICAL REFRIGERATORS 2 Sheets-Sheet 1 Filed Sept. 26, 1932 May 18, 1937. A. s. VOLPIN 2,031,123

AUTOMATIC DEFROSTER AND MOISTURE CONTROL FOR MECHANICAL REFRIGERATORS Filed Sept. 26, 1932 2 Sheets-She et 2 E snia Patented Ma 18, 1937 UNITED STATES PATENT OFFICE AUTOMATIC DEFROSTER AND MOISTURE CONTROL FOR MECHANICAL REFRIGER- ATORS The invention relates to an improvement in the collection and disposal of the moisture accumulating in refrigerators.

With the development of mechanical refrigeration, it has been found that considerable moisture accumulates upon the refrigerating coils and necessitates the defrosting of the coil at frequent intervals. The accumulation of frost upon the coiLnot only impairs the efficiency of the refrigerating unit, but causes undesirable odors to remain within the box, because of the deposits of frost, whereas if the accumulating moisture can be removed from the box as it accumulates, the efficiency of the coil is increased and the undesirable odors are removed immediately.

It is, therefore, one of the objects of this invention to provide a means and method of removing the moisture from the refrigerating chamber.

Another object of the invention is to provide a method of collecting the moisture from the incoming currents of air prior to the time when such currents of air come in contact with the refrigerating coil.

Another object of the invention is to provide an automatic defrosting mechanism for use with and to control the operation of mechanical refrigerators.

Another object of the invention is to provide a mechanism which is arranged to make a contact with the currents of air circulating in the "refrigerating chamber so that the moisture will adhere to the mechanism and in this manner be segregated and withdrawn from the refrigerating chamber.

Still another object of the invention is to provide a baffle plate in the refrigerating chamber of mechanical refrigerators for the purpose of collecting moisture at temperature above freezing.

Still another object of the invention is to provide an automatic defrosting mechanism for refrigerators wherebythe accumulation of a predetermined quantity of moisture will control the operation of the power unit so that the refrigerating coil will be out off until the coil has been defrosted, whereupon the power unit will be again out into the circuit to continue its operation.

Still another object of the invention is to provide in combination a moisture accumulator and an automatic defrosting mechanism whereby the moisture will be continuously discharged from the refrigerator and the coil will be automatically defrosted upon the discharge of a pre-determined volume of moisture from the refrigerating chamber.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawings wherein Figure 1 shows a diagrammatic view of one form of the invention and embodies both the moisture collector and the automatic defrosting mechanism.

Fig, 2 is a central vertical section of the control mechanism for the automatic defrosting device.

Fig. 3 shows a front elevation of a refrigerator box which has been equipped with one form of the present invention.

Fig. 4 is a section taken on the line 44 of Fig. 3 and shows a. side elevation of the collector mechanism.

Fig. 5 shows a front view of a refrigerating box which has been equipped with a combination I moisture collector and a defrosting device which are adapted for use in conjunction with each other to obtain automatic control of the moisture in the box.

Figs. 3, 4, and 5 show standard forms of refrigeration cabinets or boxes which are now in general use. It is usual in boxes in this type to provide a power and compressor unit which is connected to the refrigerating coil or unit which is disposed within the refrigerating chamber. In Fig. 3 the box is indicated generally at 2 and the refrigerating chamber at 3. The refrigerating coil 4 is disposed within the refrigerating chamber 3 in the usual manner.

Fig. 1 shows a diagrammatic arrangement of the mechanisms used in connection with the box and the power unit is shown at 5. The compressor 6 is operated from the power unit in any desired manner and compresses the refrigerant which then passes to the refrigerator coil 6. The power unit 5 is usually an electric motor which is controlled by a switch 1. This switch is usually wired into a power circuit, the lead Wires of which are shown at 8 and 9. An auxiliary switch II] has been provided in the Fig. 1 arrangement and this switch will be later described.

The coil 4 is usually made up of a plurality of pipes l2 through which the refrigerant is arranged to circulate, and connected to these pipes are the distributor or dissipating plates l3 which are to be cooled by the coils. The air confined within the refrigerating chamber 3 comes in contact with these distributor or dissipating plates l3 in order to be cooled and maintain the refrigerating chamber at the desired temperature.

It seems obvious that the cooling of the air in and about the refrigerating coil 4 causes the air to move downwardly by gravity around the coil. This causes an indraft of air at the top of the coil. Obviously in the refrigerating chamber the colder air being of greater specific gravity settles to the bottom of the chamber, whereas the warmer air rises to the top. When the door of the chamber is open and there is an inrush of warm air, it immediately rises to the top of the chamber and follows the general flow of circulation in the chamber, which in the arrangement of the parts shown in Fig. 3 would be in a counterclockwise direction.

With the circulation of the air as just described, the warm air rising to the top of the box and passing downwardly over the coil is caused to deposit the moisture which it carries. This moisture condenses upon thepipes l2 and the distributor plates |3 of the coil to such an extent that it interferes with the heat transfer of the refrigerating coil. In order to lessen the accumulation of this moisture in the form of frost upon the coil and its associated parts a collector pan or tray 20 has been provided adjacent to the coil 4. In the Fig. 1 modification of the invention this collector plate has been mounted upon the reservoir or tank 2| which is provided in connection with some forms of unit. If the unit is of the type which does not embody such a tank, the collector plate 20 can then be mounted upon the refrigerator coils or spaced therefrom in any suitable manner.

The supports 22 serve to space the collector plate from the refrigerating unit to such an extent that the temperature of the collector plate will be normally above freezing. It-is intended that this collector plate 20 will be cooled to some extent and be maintained at a temperature slightly higher than that of the refrigerating coil, so that when the circulation of warm air approaches the refrigerating unit it will first come in contact with this collector plate. The moisture in the air will be condensed upon the collector plate and in this manner removed from the air so that it will not be present at the time the air passes over or through the refrigerating coil. The fact that this 'mosture is condensed and accumulated at a temperature above freezing permits it to flow by gravity and thus be removed from the chamber. With this function in view, the plate 20 has been formed with a more or less concave configuration, as indicated at 24, and is provided with grooves 25 so that the moisture will drain to a dischgge pipe 26. The water is led by gravity through this pipe 26 to a cup or container 21, or the pipe 26 may lead out of the chamber as does the pipe 63 to be later described.

The container 21 forms a portion of a control mechanism to accomplish the automatic defrosting of the box. This container is shown in section in Fig. 2 and may be designed of any size so that a pre-determined amount of moisture can accumulate therein. The pipe 26 leads directly to this container and it is intended that when a pre-determined amount of moisture collects in this container that a switch such as III will be operated to cut off the power unit so that the coil will be defrosted. In order to accomplish the automatic operation of the switch It! a float member 30 has been provided in the container 21 and is intended to move upon the surface of the accumulated body of water 3|. The container 21 is provided with a needle valve 32 which normally closes the outlet pipe 33 due to the weight of the needle valve. This valve is disposed concentrically within the float 30 so that the float will slide with respect to the valve and will not move the valve until the float has raised to the elevation of the stop ring 34, which is positioned near the top of the valve. This stop ring 34 is so placed that when the float 30 engages the stop ring the needle valve 32 will be raised and the body of moisture 3| may flow out of the pipe 33. In order to retain the valve 32 open until all of the moisture has had an opportunity to escape, a bar 35 is positioned on the yoke 40 and is arranged to engage the stop ring 34 of the valve 32.

As the moisture escapes from the container 21, the float member 3!! will move downwardly with the liquid; but the needle valve will be retained in raised position by the switch mechanism Ill and the yoke 40 which will be later described. When, however, the defrosting operation has been accomplished the switch mechanism I0 is moved to closed position by the thermostat 56 to turn on the power unit, and when this switch moves to closed position the needle valve will be released to move downwardly by gravity when the yoke 40 moves down. The lower stop 38 is positioned on the valve 32 and will be engaged by the bottom of the float as the float moves down; upon release of the needle valve the float will tend to move the valve to closed position.

When the valve 32 closes the discharge of liquid will be cut off and a new charge will then begin to accumulate. This completes a cycle of the float chamber and causes a periodic discharge from the chamber of the constant accumulation of moisture from the collector plate 20.

In order that the power unit will be automatically controlled by the float 30, the yoke 40 has been provided which is separated from the float 30 and extends through the top of the container 21. This yoke is attached to the lever arm 4| which is a part of the bell crank lever 42. This bell crank lever is pivoted on the pin 43 and has two extending arms 44 and 45, the pin 43 being carried by the housing It. The arm 44 serves to support the lower end of the spring 46, the opposite end of which is attached to the blade 41 and the knife switch 48. This blade 41 is pivoted on the pin 43 and the spring 46 is under tension so that it tends to draw the blade 41 to either one side or the other of the center line joining the pin 43 and the lower end of the arm 44. This is known as a click switch, and will, therefore, snap the knife switch 48 into either closed or open position upon movement of the arm 4|. When the arm 4| moves downwardly, or to the approximate position shown in Fig. 2, the lower end of the arm wardly. This moves the lower end of the arm.

44 to the left, as viewed in Fig. 2, and when this arm passes the center .under the pin 43, the spring 46 will snap the blade 48 to the left and out of the engagement with the contact 50. This snap of the lever due to the spring 46 will also on the part of the housewife.

snap the yoke .40 upwardly so that the bar 35 will strike the stop 34 and quickly raise the valve 32.

The wires 5| and 52 are connected to the electric circuit including the wires 8 and 9 of the switch 1. When the circuit is thus broken by the opening of the switch 48, the power unit is cut off and the refrigerating coil is thus no longer supplied with refrigerant. The temperature thereof gradually raises so that the frost which has accumulated on the coil will melt.

After the coils have been defrosted, it is, of course, desirable to again close the electric circuit so that the temperature of the box will not rise beyond a desirable degree. With this in mind, the finger has been provided upon the bell crank lever 42 and this finger extends in a position to be engaged by the rod 55. This rod is in turn connected to a thermostat 56 which is mounted upon one of the distributor plates l3, or upon some other part of the refrigerator coil 4. When the temperature of the coil during defrosting rises to a degree wherein the frost will have melted from the unit, the thermostat operatesto expand, and move the rod upwardly. This movement of the rod 55 may be effected by a sylphon element which causes the end 5'! thereof to engage with the arm 45 to move the arm up-' wardly. This movement tends to cause pivoting of the bell crank lever 42 so that the lower end of the arm 44 is moved to the right, as seen in Fig. 2, until the spring 46 moves over center and clicks the blade 48 into engagement with the contact 50. The closing of this switch 48 lowers the arm 4| and the yoke 40 connected thereto to release the valve 32.

Thus we have the power unit cut off by the accumulation of moisture to permit defrosting and the power unit again turned on or cutinto the circuit when the temperature of the refrigerating coil is raised to a degree sufficient to have permitted defrosting.

From the foregoing description it is apparent that the size of the container 21 may be adjusted or varied at will, so that the defrosting of the refrigerator will occur when a pre-determined amount of moisture has accumulated.

This period when automatic defrosting will take place is independent of any time interval, but is dependent upon the accumulation of moisture. Thus if the box is opened frequently, or articles containing a considerable amount of moisture are deposited in the box, the box will automatically defrost in a shorter period than if less moisture is permitted to enter the box. a

With a refrigerator equipped with the foregoing mechanism, the housewife is relieved of any worry whatever as to whether or not the refrigerating unit requires defrosting. A certain percentage of the moisture is withdrawn from the chamber before it accumulates as frost upon the refrigerating coil. The eiiiciency of the coil is, therefore, increased. The period when defrosting is required is lengthened and the coil is automatically defrosted without further attention It is usual with refrigerators to maintain a tray beneath the refrigerating coil and when the coil defrosts the water will accumulate within this tray.

Figs. 3 and 4 show another form of the invention for accumulating and removing the moisture before such moisture is permitted to condense upon the refrigerating coil. Fig. 3 shows the usual form of refrigerating unit and crypt which is disposed at one side adjacent to the top of the box. The circulation of air in the refrigerating chamber 3, as previously stated, would be counterclockwise, the warm air rising to the top of the chamber and the cool air passing out at the base of the refrigerating coil. A collector or condenser plate has been provided in the refrigerating chamber 3 and is indicated generally at 60. This plate may take any form desired. The present form, however, illustrates a plurality of fins or baffles 6|.

A plurality of these fins may be provided and they may be arranged in any desired configuration, preferably with a view to having the greatest amount of air come in contact therewith. The plate is to be either insulated or spaced from the top or walls of the box so that the temperature of the plate will be lower than that of the walls of the box and may take other forms than here shown.

These fins or baffles will, of course, be cooler than the incoming air and the moisture of the air will condense upon the fins. Figure 4 shows these fins as being tapered toward the rear of the refrigerating chamber so that the moisture condensing upon the fins will drain to the rear of the chamber and be received in the trough 62. It is to be understood that these baffles, being at the top of the refrigerating chamber will be at a temperature above freezing so that the moisture will remain in liquid form and drain rapidly along the baffles and flow from the trough 62 into a suitable discharge or outlet pipe 63. This pipe may lead either to a container in the base of the refrigerator, or to any suitable drain. It is believed that this method of accumulating and col-* lecting the moisture before it reaches the refrigerating coil will aid materially in the refrigeration which can be obtained. The refrigerating unit need operate over a lesser period because the heat transfer will be accomplished more readily, the amount of frost condensing upon the coils will be greatly reduced and in some instances it will be unnecessary to defrost the coil at all, whereas if the coil is maintained at a very low temperature, then occasional defrosting will be necessary. The interval between defrosting periods, however, will be double or treble because of the great quantity of moisture which is removed from the air by the collector baffles before the air reaches the coil. If the air passing to the coil is dry air, then there will be little or no condensation upon the coil and the defrosting will be accomplished in a shorter time.

If the refrigerating chamber is of considerable size, or if for any other reason it is desired to maintain the baffle plate 60 and the fins ill at a cooler temperature than the top of the box, a suitable connection may be made between the collector plate and the refrigerating unit, so that the heat of the collector plate will be withdrawn by the refrigerating coil.

It is intended that the area of this connecting portion can be adjusted or varied with a view of maintaining the collector plate at the desired temperature, so that the moisture will condense thereon, but at such a temperature that the plate and fins will remain above the freezing point. With this in mind, the connecting flange 65 has been provided and is best seen in Figs. 3 and 4 as being connected to one end of the refrigerating coil and passing upwardly where it is connected with the bafile plate.

Fig. 5 shows a combination of the automatic defrosting mechanism of Fig. 1, and the com- 7 with a view of obtaining automatic defrosting 21, so that the automatic defrosting may be provided in combination with either the collector tray 20, or the moisture accumulating plate 80. Or if desired, as shown in Fig. 5, both the collector tray and the collector plates may be provided.

While the invention has been shown and described as embodying a collector tray and collector plates, it is to be distinctly understood that the invention contemplates a method as-well as a means of removing the moisture from the refrigerating chamber, and that the invention is not to be limited by the structure shown and described, but is to be limited only by the scope of the appended claims.

What I claim as new is:

1. A moisture collector for refrigerators including in combination with the refrigerating coil a collector member adapted to be contacted by the circulating air and to condense moisture from the air, means to drain off the accumulating moisture, and additional means to cut of! the source of power for the coil to cause defrosting upon the accumulation of a predetermined quantity of moisture.

2. A method of automatically defrosting refrigeration coils including condensing a portion of the moisture fromthe circulating air at a temperature above freezing and controlling the operation of the refrigerating coils upon condensation of a predetermined quantity of moisture to cause defrosting.

3. An automatic defrosting device for refrigerators including means to accumulate a portion of the moisture which is condensed from the circulating air at above freezing temperature, and means controlling the operation of the refrigeratingunit, which means is operable to cut off the operation of the unit and cause defrosting upon the accumulation of a predetermined quantity of moisture in said first means.

4. In a refrigerating unit of the character described including a moisture collector, a float operable' by the accumulation of moisture from the said collector, and control means for the ref-rigerating unit operable by said float to cut off the unit to cause defrosting thereof.

ALEXANDER S. VOLPIN.

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