US1751499A - Refrigerating apparatus - Google Patents

Description

March 25,1930. I A. M. THOMSON Q 1,751,499

REFRIGERATING APPARATUS Original Filed Nov. 22, 1926 INVENTOR @L T' u IIIIIIIIIIII II a 4x 28 ATTORNEYS Patented Mar. 25, 1930 UNITED STATES PATENT OFFICE ALFRED MORRIS THOMSON, OF NEWARK, NEW JERSEY, ASSIGNOR TO JOSEPH MER- CADANTE, OF NEW YORK, N. Y

REFRIGERATING APPARATUS Original application filed November 22, 1926, Serial No. 149,844. Divided and this application filed May 16,

1927. Serial No, 191,562.

This invention felates to a refrigerating system, and particularly to refrigerating systems of the compression type. One of the objects of the invention is to provide an im proved control. valve for regulating the flow of refrigerant from the high pressure side of the system" to the low pressure side, and to provide improved fluid connections for-conducting the refrigerant to the expansion chamber or refrigeration element.

This application is a division of my application Serial No. 149,844, filed November 22, 1926.

Refrigeration systems of the compression type include a refrigeration element located in a cooling chamber and supplied with a liquid refrigerant such as sulfur dioxide, which upon changing to the gaseous state within the cooling element produces the desired cooling effect. The system includes a pump or compressor for compressing the gasified refrigerant, a condenser for cooling and liquefying the compressed refrigerant, and an expansion valve through which the refrigerant passes to the refrigeration element. It 1s desirable to arrange the means for com-' pressing and liquefying the refrigerant in a chamber disposed in close proximity to the cooling chamber.

The so'-called expansion valve, which regulates the flow of the refrigerant from the high pressure side of the system to the low pressure side, may consist of -a float valve arranged in such a manner that the level of the liquid refrigerant within a suitable float chamber automatically regulates the passage of refrigerant through the valve to the low pressure side of the system. My invention contemplates the provision of an improved float valve which is characterized by the pro visionof a valve member cooperating with a removable valve seat. The removable valve seat is preferably arranged in such a manner that it can be readily removed from the outside of the float chamber without disturbing any of the fluid connections communicating with the float chamber. My invention may include a casing forming a float chamber and having an opening preferably at one end thereof adapted to. be covered by a closure plate which may form a support for the valve member and the valve seat;- The casing is preferably provided with an enlargementin the upper portion thereof adapted to serve as a means for collecting noncondensable gases. A suitable relief valve such as a petcock .can be provided for the purpose of exhausting the non-condensable gases from the float chamber. This feature is also of value as a means for exhausting any air which may be trapped in the system when it is being charged with refrigerant.

After the refrigerant passes through the expansion valve, it flows into the expansion chamber or refrigeration element wherein it boils and becomes gasified, thereby producing a refrigeration effect within the cooling chamber. It is a common experience to have some of the refrigerant commence to boil before it enters the expansion chamber; that is, the refrigerant has-a tendency to boil within the pipe leading from the expansion valve to the refrigeration unit. This is objectionable because it is desirable to have the refrigerant boil only within the expansion chamber, in order that the refrigeration effect will be produced at the desired point in the system. Furthermore, if some of the refrigerant boils before it gets to the expansion chamber, a coating of frost will form on the outside of the conduit leading to the expansion chamher.

I have found that by using a conduit of small cross-section and considerable length, it is possible to introduce the liquefied refrigerant into the expansion chamber with substantially all of the refrigerant in liquid form. Such a conduitof small cross-section and considerable length would offer great resistance to the flow of gaseous refrigerant.

When it is noted thata given quantity of a refrigerant such as'sulfur dioxide occupies approximately 700 times as much space in the gaseous state as in the liquid state, it can be appreciated that a very small conduit may be suitable for supplying suflicient liquid refrigerant at low velocity, whereas this conduit would be entirely inadequate to supply the same quantity of gaseous refrigerant within the same period of time. In any event, it has been observed that where such a small conduit is employed, there is practically no tendency for the refrigerant to become gasified within the conduit. The conduit remains free from frost, and the gasification of the refrigerant takes place almost.

- entirely within the expansion chamber.

The resistance offered by a small conduit to the flow of refrigerant through the same is such that'the conduit acts as a pressure reduction device, that is, the pressure of the refrigerant at the delivery end of the conduit is materially less than that at the intake end of the conduit. I have found that this effect is so pronounced that it is possible to eliminate the pressure reduction valve between the high pressure sideof the system and the low pressure side. The small conduit is useful in conjunction with an expansion valve, however, because it preventsboiling of the refrigerant between the valve and the expansion chamber.

The various objects and advantages of my invention can be best understood by considering the following detailed description, which is to be considered in conjunction with the accompanying drawings, in which Fig. 1 is a vertical section view of the refrigeration system embodying my invention; Fig. 2 is an enlarged vertical section View of one embodiment of my improved float valve; and

Fig. 3 is an enlarged section view of one form of conduit suitable for introducing the refrigerant int-o the expansion chamber.

In the drawings, and more particularly in Fig. 1, the 'refrigeratingsystem of the present invention has been shown installed in a domestic refrigerator of the conventional type. This refrigerator comprises a lower mechanism compartment or-chamber 1 contaming the compressing, condensing and expanding mechanism .of the system, a cooling chamber'2 containing the refrigeration element and a food chamber 3, the food chamber and the cooling chamber being prefer ably connected by the passages 4 and 5 to permit the circulation of air therebetween, and being enclosed by suitable heat insulating Walls'6. The lower compartment 1 is preferably provided'with ventilating open-t ings 7 in the side walls thereof.

The refrigeration or expansion element, designated as a whole as B, may take any suitable form, and as shown comprises a tank or header 8 having connected thereto a plurality of tubular passages 9 surrounding the freezing compartments 10 in which liquids or foods may be frozen. The refrigeration element R is preferably supported from the upper wall of the cooling chamber 2 by the supporting bracket 11. An inlet pipe 12 and an outlet pipe 13 are connected to the element B through suitable valves 14 and 15, respectively, these pipes being connected to the compression and expansion apparatus as hereinafter described. The compression and expansion apparatus, located in the lower chamber 1, comprises a suitable source of power such as a motor 16, directly con-- nected to a compressor 17 through a shaft 18. The compressor may be of any suitable form, and as shown comprises a pump of ,the rotary or gear type. The outlet pipe 13 from the refrigeration element R is connected to the intake of the compressor 17, while the outlet of the compressor is connected to the condenser coils 19 which are cooled by air currents from a fan 20 mounted onthe shaft 18. From the lower end of the condenser coils 19, a pipe 21 extends to the expansion apparatus, which will be hereinafter described, and thence the refrigerant cycle is completed by a connection between the outlet of the expansion apparatus and the intake pipe 12 of the refrigeration element R.

The expansion valve unit, which comprises an important feature of the present invention, is shown in an enlarged sectional view in Fig. 2. This valve, designated as a whole as V, comprises a chamber 22 constructed of a suitable metal and having an enlarged and somewhat spherically shaped portion at one end thereof, the opposite end being provided with an opening which is closed by a removable head or plate 23. A relief valve in the form of a petcock 21 is preferably secured in an opening at the upper side of the enlarged portion of the chamber 22. An inlet pipe connection 25 of any suitable construction is secured in an opening 26 in the upper wall of the chamber 22 at a point near the removable head 23 as shown. I

In the preferred embodiment of the invention illustrated, the expansion valve pro er is located at the outlet port of the cham er 22, and comprises a float operated needle valve. This valve and its operating mechanism are carried by the plate 23 in an enlarged portion thereof, and comprise a'removable tubular valve seat 28 secured in an" opening I in the plate 23 by means of a tubular set screw or nipple 63, and a needle or valve member 29, slidably supported in alignment with the seat 28 in an inwardly projected extension 30 of the head 23. A valve chamber31 is provided adjacent the inner end of the valve seat 28, and is connected to the interior of the chamber 22 by a downwardly disposed port over this port to prevent the entrance of foreign matter into the valve mechanism. The

float mechanism for operating the valve member 29 comprises a float 34 secured to the end of a lever 35,-the opposite end of which is? pivotally secured to a bracket 36, integral with or suitably secured to the head 23. A

'short lever 37 is suitably secured tb thelever rising of thel'iquid level within this chamber serving to lift the float 34 and so draw the valve member 29 away from the valve seat 28 to open this valve. With this arrangement,

the refrigerant is permitted to .pass from the valve unit V in t e liquid state only, since when the liquid level drops below a predetermined point, which point is above the valve port 32, the float 34 is lowered to a point at which the valve member 29 is moved into contact with the valve seat 28.

' 25 An openin 39 is provided in the enlarged portion 27 o the head 23 in alignment with the valve seat 28, this opening being of a larger diameter than the seat 28 and the set screw 63, whereby the set screw and seat may be removed therethrough without disturbing any of the pipe connections of the system. This opening 39 is normally closed by a plug 40, a washer or gasket 41 being rovided to insure a gastight closure. A suita le outlet pipe fitting 42 is secured in'an opening 43 communicating with the opening 39 at the outer, end of the valve seat 28, the opening 43 extending at an angle to the axis of the seat, 28, as shown. The head 23 may be secured to the chamber 22 in any suitable manner, a gasket 44 being preferabl provided between the head andthe cham er to insure a tight closure.

The pipe 21 is onnected throu h a suitable T-fitting 45 to a ipe 46 connected to the pipe fitting 25 at the inlet port 26 of the chamber 22, a valve. 47 being provided in the pipe 46.

From the T-fitting 45, a short pipe 48i having a valve 49 therein, leads to a second -fitting 50. A pipe 511eads fromthe outlet fitting 42 of the expansion valve unit V through a third Tfitting 52 to the ipe 12 of the refrigeration elementR, and t e T-fittings 52 and 50 are connected'by a short pipe. 53 having a valve 54 therein. A pressure reduction coil 55 is connected to the T-fitting 50 through a check valve 56 'of suitable design, the upper end of the coil 55 being connected to the pipe 12 leading to the refrigeration element B through a valve 57, as shown. A valve 58 ,is provided in the pipe 59 between the T-fitting 52 and the point at which the coil 55 is connected to the pipe 12.

The coil 55 preferably comprises a 'comparatively long pipe of very small diameter,

a pipe approximately twent feet long and one-sixteenth of an inch in' 'ameter having been found suitable for this purpose when delivering refrigerant at the rate ofapproximately cu. ft. per minute. The dimensions of the C011 55 are so arran ed to revent the boiling and gasifying oft e refrigerant liquid as heretofore described, the long pipe of small diameter permitting the pressure of the liquid-to be reduced at a very slow rate, and so, maintaining the refrigerant inthe liquid state as it passes through the coil.

[By the arrangement of the pipe connections .andvalves described, the entire flow of the refrigerant may be diverted through either the expansion valve unit V or the coil 55, or the refrigerant may be caused to flow through the valve unit V and the coil 55 in series. For example if it is desiredto by-pass the entire flow of the refrigerant aroundthe coil 55 and through the expansion .valve unit V, the valves 49, 54 and '57 are closed, and the valves 47 and 58 are opened, and with this setting of the valves, the refrigerant flows from the pipe 21 through the p 'e' 46, the expansion valve unit V, and the-pipes 51, 59' and '12 to the refrigeration element. R. If it is desired to by-pass the entire flow of refrigerant around the valve unit. V, and through the co1l 55 the valves 47, 54 and'58 are closed and the valves-49 and 57 are opened, the refrigerant .then flowing from the' pipe 21 through the T-fitting 45, the pipe 48, the T- fitting 50, the coil 55 and the pipe 12 to the refrigeration element B. When it .is desired to permit the refrigerant to flow through the expansion valveunit'V and the coil 55 in series, the valves '49 and 58 .are closed and the valves 47, 54 and 57 are opened. With the valves arranged in this manner, the refrigerant first passes through the expansion valve V y and then passes through the coil 55 where the refrigerant then passes under reduced pres sure to the refri eration unit B.

When the entire flow. of refrigerant is diverted through the coil 55, a considerable back-pressure is built up in this coil, and when the compressor 17 is temporarily stopped, there is a tendency for the refrigerant under this back-pressure to flow back through the pipe 21 and the condenser coils 19 and to operate the compressor '17 backward, the retin the refrigerant to flow from the pipe 21 to t e coil 55, but preventing the return flow of the refrigerant.

In order to further prevent the boiling or absorption of heat by the li id refrigerant as it passes through the coilf55 and to the pressure is gradually reduced and the liquid refrigeration element R, a special double walled conduit may be used in the construction of the coil 55 and the ipe connections described. A conduit of this type has been shown in section in Fig. 3, andcomprises an ,inner tube or pipe 60.01. comparatively small tween theoutlet end of the condenser'coils 19 and the intake of the refrigeratiomelement R, thus effectively insulating the entire refrigerant feeding system against the absorption of heat.

The expansion apparatus of the present invention presents many advantageous features. By the use of the improved expansion valve unit V, the refrigerant is pernntted to pass to the refrigeration element R in the liquid state only, and means are provided in the expansion valve unit for drawin off an air or non-condensable gases whic may ave become trapped in the system. The'valve seat 28 of the needle valve in the unit V may be readily removed for cleaning or replacement by the removal of the plug 40, and this operation may be performed without altering the pigs connections of the system. The pressure re uction coil 55,. connected to the expansion valve unit V throu h the pipe connections and valves as descri ed, provides means for reducing the pressure of the refrigerant at any desired or suitable rate, and by the use of this combination of the coil and expansion valve, the refri erant may be delivered to the refrigeration e e'ment without undue boiling or absorption of heat thereby.

Although the refrigerating. system of the present invention has been described in connection with a' single specific arran ement of devices and apparatus, it should clearly understood-that the invention is not limited to the exact means shown, and that certain changes, modifications and combinations may be made without de arting from the scope of the invention as efined by the appended claim.

I claim:

In a refrigerating a paratus, an expansion valve comprising a cat chamber, a float therein, a support, a valve member carried by said support and connected to said float, a valve seat carri by said supportand removable therefrom, removable means engaging .said support accessible from the exterior 0 said float chamber-for normally holdin said. valve seat in place, a valve chamber ad acent to said valve seat and, having an openmg in line with the longitudinal axis thereof said

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