US2016056A - Liquid circulating system - Google Patents

Description

Oct. l, 1935. N. M. SMALL 2,016,055,

' L'IQUID CIRCULATING SYSTEM Filed Aug. l, 1935 Patented Oct. 1,1935

UNITED STATES 2,016,056 LIQUID CIRCULATING SYSTEM Norman M. Small, Waynesboro, Pa., assignor to Frick Company, Waynesboro, Pa., a corporation of Pennsylvania Application August 1, 1935, Serial No. 34,288

Claims.

tion with the evaporator.

Heretofore it has been customary to provide a relatively large body of liquid refrigerantin a refrigerating system and particularly in the evaporator in order to submerge a very substantial part of the heatexchange surfaces of the evaporator.

It is an object of the present invention to provide a refrigerating system wherein maximum heat transfer is obtained with a minimum of refrigerant or a refrigerating system in which the amount of refrigerant necessary for satisfactory operation of the system is materially reduced without any substantial reduction in heat transfer surfaces maintained wet with liquid refriger Y ant, and at the same time to provide a system of this character having an evaporator or heat exchange unit capable of improved heat transfer.

Another important object of the invention is to provide a refrigerating system having an evapf orator or heat exchange unit'in which the refrigerant is both admitted to and withdrawn from or near the top or highest point of the same so that the vapor generated in cooling the incoming liquid to the temperature of the evaporator is not permitted to come in contact with the heat exchange surface, thus permitting a. reduction of heat exchange surface which results in improved efficiency.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing wherein: The ligure is a diagrammatic view illustrating one application of the invention. v

Referring to the accompanying drawing in which similar reference characters indicate similar parts, a refrigerating system is provided having a compressor I0 which discharges compressed refrigerant vapor through a pipe II into a condenser I2. In the condenser the compressed refrigerant is cooled and consequently liquefied. Liquid refrigerant from the condenser is discharged into a heat exchange unit such as a cool` er or evaporator I3 by means of pipes I4, I5, I5, I1

header I8 and discharge distributing device such as spray nozzles or the like. I9.

The supply of liquid refrigerant through the pipes I4, I5, IB, I1, I8 and distributing device I9 may be controlled by any ordinary means for controlling the now of liquid refrigerant in a refrigerating system such as in the preferred construction, for example, an electric iioat switch 20 subject to liquid level in the condenser and operating in connection with a magnetic shut-olf valve 20' 5 as shown or other means such as a float valve. or an automatic expansion valve to maintain a set suction pressure, or a thermal expansion valve to maintain a set super heat in the suction gas or a hand control valve. l 10 Instead of liquid from the condenser being admitted into the evaporation or cooling unit in the manner shown, it may be admitted directly into the evaporator through pipe. 2|, such pipe being connected to a sump or well 22 of the evaporator. l5 Circulation through the pipes I6 and 2| may be controlled respectively by hand valves I6I and 33, when valve 33 is open and valve I6 closed refrigerant can pass through the pipe 2I directly into thewell 22 and-when the valve 33 is closed and 20 the valve I6' open refrigerant must pass through the pipes I6 and I1 and be sprayed through the distributing device into the evaporator. I

In the evaporator or cooling unit I3, the liquid refrigerant boils off `or vaporizes and the vapor 25 thus produced is Withdrawn through outlets 23 and connections 24 to a header 25 connected to a suction line 26 extending into the suction side of the compressor. The pipes I8 which supply the liquid refrigerant to the evaporator are mounted 30 concentrically of the vapor discharge passages 23. This construction provides for Withdrawal of the vapor generated in cooling the incoming liquid to the evaporator temperature directly through the discharge outlets before the vapor can blanket 35 the heat exchange surface. The discharge outlets from the cooling unit are around the inlets to the spray nozzles I3 in the preferred embodiment of the invention although the invention is not so limited but contemplates withdrawal of the vapor 40 near the top of the evaporator. As is well known heat absorption in an evaporator is iproducedby the change in state of the refrigerant from a liquid to a vapor, this heat going into latent heat of vaporization. capacity of the gaseous refrigerant to absorb heat is almost negligible and therefore in order to provide the most effective heat transfer the heat transfer surface must be constantly immersed or in contact with Vliquid refrigerant. The usual 50 method is to submerge the h'eat transfer surface with liquid refrigerant by providing a suillcient body of liquid that the height ,of the liquid will be ofsuch an extent that the heat transfer surface Willbe submerged.

The 45- In the practice of the present invention in order not to require a relatively large bodyof liquid refrigerant the heat transfer surface is maintained wetted by being sprayed with liquid refrigerant. This provides a relatively thin body of liquid refrigerant in contact with the heat transfer-surface which is suihcient to absorb heat and produce the change from liquid to vapor in so doing. A superfluous quantity of refrigerant or a greater amount of refrigerant than is necessary is avoided.

The sump or well 22 in the bottom of the evaporator or cooling unit collects a substantial body of liquid refrigerant without' the necessity of maintaining an excessive amount of refrigerant in the evaporator or in the system. The liquid is withdrawn from the sump 22 by a pump 21 which has its suction side connected by means of a pipe 28 with the sump 22, the discharge side of the pump being connected by a pipe 29 into the liquid line I1.

With this construction liquid refrigerant is withdrawn from the well or sump 22 in the bottom of the evaporator and forced around and discharged through the distributing device I9 into the evaporator over the evaporating or heat transfer surfaces of the same. As shown in the drawing the evaporator is by way of example only of the multi-pass shell and tube construction having inlet and outlet connections 3| and 32 respectively. The tubes are adapted to have water or other fluid to be cooled circulated therethrough.

In operation, compressed refrigerant is liqueed in the condenser and discharged past the magnetic stop valve into the evaporator through the distributing device I9. The amount of the liquid so discharged being controlled by the magnetic stop valve and electric float switch 20 subject to liquid level in the condenser, or other control means. 'I'he discharge of the liquid refrigerant is in the form of a spray over the tubes 30 or other construction containing water, brine or other substance to be refrigerated and the liquid refrigerant coming into contact with the tubes 30 or other heat transfer surface absorbs the heat therefrom and is vaporized thereby, the vapor being withdrawn and sucked back to the compressor through the suction line 26. During this operation some of the liquid refrigerant will accumulate in the sump or well 22 and will be recirculated by the liquid pump 21 which discharges the liquid through the distributing device I9.

While the heat transfer surface is shown of the shell and tube construction the invention is not so limited and the evaporator or cooler is intended to represent any desired device of this character.

It will be readily apparent from the foregoing that an important feature of the present invention resides in the provision of an evaporator in which a relatively small quantity of liquid refrigerant is utilized for maintaining the maximum quantity of heat transfer surface wet and unused liquid is collected in the bottom of the evaporator and discharged overl the heat ex change surface by any desired means as for example, through spray nozzles.

It will be obvious to those skilled in the art that various changes may be made in my device withoutdeparting from the spirit of the invention and therefore I do not limit myself to what is shown in the "drawing and described in the specification but orhygas indicated in the appended claims,

What is claimed is:

1. In a refrigerating system, refrigerant liquefying apparatus, a heat exchange unit, means for spraying liquid refrigerant into and withdrawing vaporized refrigerant from said heat ex- `5 change unit at substantially the same point whereby the vaporized refrigerant adjacent said spraying means may be withdrawn before it contacts with the heat exchange unit.

2. Ina refrigerating system, an evaporator, supply and discharge connections to said evaporator through which refrigerant is admitted to and withdrawn from said evaporator, each supply connection being in closeproximity to a discharge connection whereby refrigerant vapor-ized shortly after admission to the evaporator may be withdrawn before it comes in contact with heat exchange surface within the evaporator.

3 In a refrigerating system, an evaporator, supply and discharge connections to said evaporator through which refrigerant is admitted to and withdrawn from said evaporator, each supply connection being in close proximity to a. discharge connection whereby refrigerant vaporized shortly after admission to the evaporator may be withdrawn before it comes in contact with heat exchange surface within the evaporator, and means for withdrawing refrigerant from said evaporator and discharging it through the supply connections directly into said evaporator.

4. In a refrigerating system, an evaporator, a liquid line, a suction line, a liquid header in the liquid line, a suction header in the suction line, supply connections from the liquid header to the evaporator, spray nozzles in the evaporator at the ends of said supply connections for causing liquid supplied to be sprayed into the evaporator,

,suction connections from said suction header to said evaporator, each supply connectionr to said evaporator being in close proximity to a suction connection whereby refrigerant vaporized immediately after being sprayed into the evaporator may be withdrawn from the evaporator before it comes in contact with heat exchange surface, a

supply connection from the supply line to the bottom of the evaporator adapted to be used with the supply through the header or independently of the same for admitting refrigerant to the evaporator, and means for withdrawing liquid refrigerant from the bottom of said evaporator and discharging it into the evaporator through said supply connections.

5. In va refrigerating system, an evaporator, a liquid line, a suction line, a liquid header in the liquid line, a suction header in the suction line, supply connections from the liquid header to the evaporator, spray nozzles in the evaporator at the ends of said supply connections for causing liquid supplied to be sprayed into the evaporator, suction connections from said suction header to said evaporator, said supply and suction connections being concentrically arranged whereby refrigerant vaporized immediately after being sprayed into the evaporator may be withdrawn from the evaporator before it cornes in contact-with heat concentrically arranged supply and discharge l and withdrawn from said evaporator, each sup.- Y

shortly after admission toth/e evaporamnmay/supply connection fron'"the supplywllneto thew74 be-withdrawn before it comes in contact with heat exchange surface within the evaporator, and means for withdrawing refrigerant from said evaporator and discharging it through the supy ply connections directly intosaid evapor/ati`\- 8TIn-afrefrig'eing system, an evaporator, supply and discharge connections to said evaporator through which refrigerant is admitted'to iilconnection'vbeing in close proximity to a discharge connection whereby refrigerant vaporized shortly after admission to the evaporator may be withdrawn before it comes in contact with heat exchange surface within the evaporator, 'a supply .connection from the supply line to the bottom of the evaporator adapted to be used with the supply through the header or independently of the same for admitting refrigerant to the evaporator.

9. In a refrigerating system, an evaporator supply and discharge connections to said evaporator through which refrigerant is admitted to 5 and withdrawn from said evaporator, each supply connection being in close proximity to a dis y charge connection whereby refrigerant vaporized shortly after admission to the evaporator may be withdrawn before Vit comes in contact with 10 hieighange surface within the evaporator, a

bottom of the evaporator adaptedto be used with the supply through'I the header or independently of the same for admitting refrigerant to the 15 evaporator, and means for withdrawing liquid lrefrigerant from the bottom of said evaporator and discharging it into the evaporator through said supply connections. N@

10. In a refrigerating system, an evapollatonjo supply and discharge connections to said evaprator through which refrigerant is admitted to and withdrawnJromv-said evaporator, 'each supply connection being in -suiliciently close proximity to a discharge connection that refrigerant vaporized shortly after admission to the evaporator may be withdrawn before it comes in contact with `heat exchange surface within the evaporator. 4

NORMAN M. SMALL.

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