US2554920A - Feed for refrigerant injector for evaporators - Google Patents

Description

y 1951 H. A. PHILLIPS 2,554,920

FEED FOR REFRIGERAN'I' INJECTOR FOR EVAPORATORS Filed Aug.- 23, 1947 INVgNTpR.

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" Patented May 29, 1 951FEED roe 2554,92!) IGERANT INJECTbRFOR EVAPORATORS Harry A. Phillips, Chicago, 111. Application August-23, 1947, Serial No. 770,251 emits. (chm- 8) The invention relates to a system or refrigeration and has referen'cqme're paiucuie riy to a method and apparatus for ifiodulatiii'g the now of liquid refrigerant through a nozzle by controlling the temperature of the liquid refrigerant.

In my Patent No. 2,123,021 granted July 5, .1938 I describe and claim "the use of "liquid refrigerant injectors for reciieulating liquid refrigerant through, an evaporator equipped with a surge drum. By the 'methodfo'f parallel flow, as explained in the patent, improved circulation of the liquid refrigerant through the evaporator coils is secured with automatic control of therefri'gerating elfect under varying load conditions. This parallel method of refrigerant flow is preferred to pressure regulation in front of the injectors for the reason that the hunting and cycling action is apt to be excessive when pressure control is employed.

As a result of further investigations I have foundthat the flow of liquid refrigerant through an injector nozzle of fixed size can be -modulated by controlling the temperature of the entering liquid. With fixed condenser and evaporator pressures the How of liquid through the nozzle is increased by sub-cooling the liquid and is decreased by allowing the temperature of the liquid to rise and approach th temperature of the liquid refrigerant condensed in the receiver. Thus a very desirable type of liquid flow mod-ulation of refrigerant injectors is establis'hed, based on the degree of cooling .of the liquid refrigerant supplied thereto.

Accordingly, an object of the invention is to provide a refrigerating systemincluding apparatus which will modulate the flow ofliquid refrigerant through a nozzle of fixed size in response to the temperature of the liquid refrigerant supplied to thenozzle.

A further object of the invention resides -.in the provision of apparatus for use in connection with refrigerant injectors which will 'fmodulate the fiow'of liquid refrigerant through the injector in response to "the temperature of the liquid refrigerant and wherein the modulating liquid flow may be combined with the l aiallel flow method of my Patent No. 2,1'23j021 to secure improved liquid control for a large number of evaporators operating under maximum variaations in load conditions.

Another object of "the invention is to provide apparatus for sub-cooling the liquid refrigerant supplied to-one'or'more refrigerant injectors and which win incorporate means such as a "fiber valve for controlling the cooling ei fecit.

A further object or the invention resides in the provision :of apparatus as above described which Will essntittllfirbdm'pri's'ea "heat exchanger for cooling the high pressure liquid refrigerant with pro'visien being made for draining liquid refrigerant and oil from "tlle'h'ealt excha'i'ig'r to the surge "drum for vehting re'frigerant gas fromtlie exc anger to chesurige dium or to some ot rparrortneeystein. K

With these and various other objects in view. the invention may consist of certain novel featliies of construction and operation, as Will be more fully described and particularly pointed out in the specification, "drawings and claims appendedheretb.

Infthe drawings illustrate an em'bbdimerit of the "device and wherein like reference characters are used to designate like parts:

Figure 1 is "a diag'ammatie view showing a conventiona re rigerating 's'y'stln equipped with the meditating flow apparatus 'of the inventidn, and

Figure 2 "is a liorifidhta'l sectional view taken through the evaporator substantially along line 2- 2'6f Figure 1. V

The'r'efrige'ratilig system shown in the drawihgs cohsi'stsef'a'bbinfiiessol ill or the usual til e having an operati'fi i'shaft TI to which is s'eoiIred pulley 1'2 diti eh tlirouh belt I13 by all electric "meter or other 'Siii'table source "of power, not "Shawna cause 'rtitation of the operating shaft III of the compressor. The pressure "head 'of the lcoiiipressor is formed with a plurality or 'fifis I l providing cooling surfaces for the pressure head which is-supplied with refrigerant ,gas ,by the suction line [5 connecting with'the pressure head at the base thereof. The refrigerant gas is compressedhy the compressor, the temperature and pressure of the same being thereby raised, and this high pressure refrigerant gas is then delivered to the compressor discharge line [6. V

The refrigerant gas "from the 'compressor discharge line enters the condenser-receiver IS .in the form "of- .an elongated tank having water cooling associated therewith for which purpose the tank has connectionwi-th awater inlet line 20 and a water outlet line 2i. The condenser-receiver has connection at its lower right hand end with the liquid refrigerant supply line 122. The high pressure refrigerant gas supplied to the condenser-receiver is condensed by the cooling action of the water cooling means and said liquid refrigerant condensing within tank [8 accumulates 'in the bottom of the tank and is eventually supplied to said liquid refrigerant line.

The evaporator of the refrigerating system is designated bynumeral 23. The evaporator is conventional in design and construction including a plurality ofevaporator coils 24 which extend horizontally in parallel relation, being supported by fins to form the evaporator structure. At their inlet end the coils have connection with aliquid header 25 and at their outer end the coils connect with agas header 26. The gas header extends upwardly to connect with asurge drum 21, and said header terminates within the surge drum in the upper portion thereof so that the evaporated refrigerant is discharged within the drum while liquid refrigerant is prevented from entering the gas header. The suction line also connects with and terminates within the surge drum in the upper portion thereof and therefore the refrigerant gas accumulating within and generated within the surge drum is suctioned off and eventually supplied to the compressor.

In accordance with the invention theliquid refrigerant line 22 has connection withfloat valve 28, said valve having suitable connection at 29 to thesurge drum 21 and being controlled byfloat 38. Thefloat 30 is located within the surge drum and more particularly in the lower portion of the drum so as to float on the liquid refrigerant accumulating in the lower portion of the drum. Accordingly, the position offloat 38 varies as the liquid level withinsurge drum 21 may vary. This action of thefloat 30 controls thevalve 28 and thus regulates the quantity of liquid refrigerant flowing fromline 22 through the valve to the feed line 3| for the sub-cooler to be presently described. Theline 32 extends parallel to line 3| and is in efiect a continuation of theliquid refrigerant line 22 connecting therewith at 33 in advance ofvalve 28.

The sub-cooler or auxiliary evaporator for cooling the liquid refrigerant inline 32 comprises a cylinder 34 through which theliquid refrigerant line 32 extends, said line having a number of bends Within the cylinder in order to provide the necessary surface area for cooling the liquid refrigerant flowing throughpipe 32 to the desired temperature. At the exit end of the sub-cooler 34 thepipe 32 connects with a liquidrefrigerant feed line 35 which in turn connects at 36 with arefrigerant injector 31. The refrigerant injector essentially consists of a'housing 38 enclosing nozzle 48. Thenozzle 40 receives liquid refrigerant directly from therefrigerant feed line 35. Thehousing 38 in turn connects at its upper end with theinlet header 25 and intermediate its ends said'housing has connection with pipe 4| comprising an auxiliary feed line for liquid refrigerant. Said pipe 4| has connection with the bottom ofsurge drum 21. Liquid refrigerant from the sub-cooler 34 is drained to the surge drum by means ofconnection 42 having aneedle control valve 43 which provides for regulation of the quantity of liquid refrigerant draining from the sub-cooler. Conduit 44 connects the upper portion of the cooler with the surge drum and accordingly said conduit operates to vent gaseous refrigerant from the same, delivering said refrigerant to the surge drum whereby said gaseous refrigerant iseventually suctioned 01f by line I5 and returned to the compressor.

it will be understood that the liquid refrigerant inline 22 is at a high pressure and a relatively high temperature. This refrigerant will be delivered to the parallel branch lines 3| and 32. Thus the total quantity of liquid refrigerant flowing inline 22 is divided, with the major portion being delivered toline 32 and a relatively minor portion being delivered to line 3| as controlled byfloat valve 28. The liquid refrigerant from line 3| is delivered to the sub-cooler 34. The cooler 34 connects with thesurge drum 21 and with the suction line of the compressor so that the liquid refrigerant supplied to the cooler is evaporated to produce the desired cooling effect. Actually the coolerv 34 comprises an auxiliary evaporator of the flooded type and a heat exchanging effect therefore takes place between the evaporating refrigerant within the cooler and the liquid refrigerant flowing throughpipe 32. The temperature of the liquid refrigerant inpipe 32 is materially lowered and the gaseous refrigerant generated within the cooler is vented to the surge drum by pipe 44. Also the excess liquid refrigerant within the cooler 34 is continuously drained byconnection 42 to thesurge drum 21. Additional liquid refrigerant is supplied to the surgedrum as a result of slop-over of refrigerant from thegas header 26. The level of this refrigerant within the surge drum determines the position offloat 30 which in turn controlsvalve 28 and thus the supply of refrigerant to the cooler.

When the level of liquid refrigerant within the surge drum is high thefloat 30 is elevated andvalve 28 is closed so that the flow of liquid refrigerant to the cooler is terminated. When different conditions exist, that is, when the liquid level within the surge drum is below its maximum level, thefloat 38 will drop to a lower position, openingvalve 28 and supply of liquid refrigerant to the cooler will be resumed.

The conditioned refrigerant from the cooler is supplied by thefeed line 35 to thenozzle 40 of theinjector 31. Since this refrigerant is at a high pressure it will issue from the nozzle with considerable velocity. The liquid refrigerant having surrounding relation with the nozzle is supplied thereto by auxiliary pipe 4| which drains said refrigerant from the surge drum. As a result of the injector action of the refrigerant issuing fromnozzle 40 the velocity of the refrigerant flowing throughheader 25 is greatly accelerated and thus the flow of refrigerant through the evaporator coils 24 is materially increased.

The modulating action of the injector is controlled by the cooling of the liquid refrigerant supplied to the nozzle. In explanation it can be pointed out that as heat is removed from the entering liquid refrigerant the amount of flash gas generated at the nozzle decreases and the actual weight of the liquid refrigerant flow increases. The modulating action is controlled by one of the most common means of liquid control, namely, a float valve. In operation, therefore, thefloat valve 28 will control liquid flow adequate to modulate the amount of liquid passed through the nozzle and which has a capacity many times the capacity of the float valve in refrigerating effect.

A wide variation of liquid control becomes possible through the use of the liquid-temperature modulation system as described in combination with the parallel flow method through the injector. The refrigerant supplied by the auxiliary feed 4| is recirculating refrigerant and the quantity of the same may be several times as great,

greased during a given period, as refrigerant supplied by pipe-22 and drawn away through the suction line 1 5 corresponds to the refrigerating effect or l'oar'l during such a period. -By the recirculation of liquid through the coils it is possible to secure heavy duty operation since the maximum heat transmission is obtained from the coils under difiicult load conditions regardless of leadchanges. The present method of control in combination with the injector also permits flooding of. a multiplicity of evaporators, In the past it has ibeen possible to take care of only minor load changes in evaporatorshaving continuous preeessmg. The tern perature method of modulation friakes it pos sible to apply inj ecter-recirculatory equipment to a large number of evaporators operating under varying loadfconditions; i

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. In refrigerating apparatus, the combination with an evaporator and a liquid refrigerant line for supplying refrigerant thereto, of a surge drum interposed in the suction line of said evaporator for accumulating liquid refrigerant to be recirculated through the evaporator, an injector having a nozzle of fixed size located at the inlet to the evaporator and connecting with the liquid refrigerant line whereby said refrigerant is delivered to the evaporator by the injector action of the nozzle at a high velocity, an auxiliary c001- ing drum having the liquid refrigerant line extending through the same, means supplying liquid refrigerant to the drum so that upon evaporation thereof the same has heat exchanging relation with the liquid refrigerant line, and a float valve for controlling the supply of liquid refrigerant to the cooling drum, the float of said valve being located within the surge drum whereby the level of the refrigerant in the surge drum controls the actuation of the valve.

2. In refrigerating apparatus, the combination with an evaporator and a liquid refrigerant line for supplying refrigerant thereto, of a surge drum interposed in the suction line of said evaporator for accumulating liquid refrigerant to be recirculated through the evaporator, an injector located at the inlet to the evaporator, said injector including a nozzle of fixed size connecting with the liquid refrigerant line whereby said refrigerant is delivered to the evaporator by the injector action of the nozzle at a high velocity, an auxiliary refrigerant feed line connecting the surge drum with the injector for supplying recirculating liquid refrigerant from the drum to the injector in surrounding relation with the nozzle thereof whereby said recirculating refrigerant is fed to the evaporator by the injector action of the nozzle, an auxiliary cooling drum having the liquid refrigerant line extending through the same, means supplying liquid refrigerant to the drum so that upon evaporation thereof the same has heat exchanging relation with the liquid refrigerant line, and a float valve for controlling the supply of liquid refrigerant to the cooling drum, the float of said valve being located within the surge drum whereby the level of the refrigerant in the surge drum controls the actuation of the valve.

the teen quantity hr refrigerating apparatus, the combination with an evaporator and a liquid refrigerant line for supplying refrigerant thereto, of a surge drum interposed in the suction line of said evaporator for accumulating liquid refrigerant to be reoireulated through the evaporator, an injector located at the inlet to the evaporator, said 'in jector including a nozzle of fixed size connecting with the liquid refrigerant line whereby said refrigerant is delivered to the evaporator by the injector action of the nozzle at a high velocity, anauxilia ry refrigerant feed line connecting the surge drum with the injector for supplying recirculating liquid refrigerant from the drum to th injector in surrounding relation with the nozzle thereof whereby said recirculating refrigerant is fed to the evaporator by the injector action of the nozzle, means controlling the tem pera'ture-o'f the refrigerant in the liquid refrigerant line for the purpose of modulating the flow of the refrigerant through the nozzle, and other means for regulating said temperature controlling means in accordance with the level of the liquid accumulated in the surge drum.

4. In refrigerating apparatus, the combination with an evaporator and a liquid refrigerant line for supplying refrigerant thereto, of a surge drum interposed in the suction line of said evaporator for accumulating liquid refrigerant to be recirculated through the evaporator, an injector located at the inlet to the evaporator, said injector including a nozzle of fixed size connecting with the liquid refrigerant line whereby said refrigerant is delivered to the evaporator by the injector action of the nozzle at a high velocity, an auxiliary refrigerant feed line connecting the surge drum with the injector for supplying recirculating liquid refrigerant from the drum to the injector in surrounding relation with the nozzle thereof whereby said recirculating refrigerant is fed to the evaporator by the injector action of the nozzle, means controlling the temperature of the refrigerant in the liquid refrigerant line for the purpose of modulating the flow of the refrigerant through the nozzle, said means including an auxiliary heat absorbing element having heat exchanging relation with the liquid refrigerant line, a drain from the element to the surge drum for draining liquid refrigerant, and a gaseous refrigerant vent connecting the element with the surge drum.

5. A refrigeration control method for an evaporator wherein liquid refrigerant is recirculated through the evaporator, which consists in dividing the total quantity of liquid refrigerant supplied to said evaporator into a first portion and a second portion, flowing the first portion through a heat exchanger and then feeding the same to an injector located at the inlet to the evaporator for injection by the nozzle of said injector, regulating the quantity of the second portion in accordance with the demands of the evaporator, supplying the second portion to the heat exchanger for vaporization whereby to cool the first portion in advance of feeding the same to the injector so as to modulate the flow of liquid refrigerant delivered by the injector, accumulating unevaporated liquid refrigerant returning from the evaporator and from the heat exchanger to provide a quantity of liquid refrigerant for recirculation, and feeding said last mentioned refrigerant to the injector in surrounding relation with the nozzle thereof to supply additional refrigerant to the evaporator by the injection action of said injector.

6. A refrigeration control method for an evaporator wherein liquid refrigerant is recirculated through the evaporator, which consists in dividing the total quantity of liquid refrigerant supplied to said evaporator into a major portion and. a minor portion, flowing the major portion through a heat exchanger and then feeding the same to an injector located at the inlet to the evaporator for injection by the nozzle of said injector, supplying the minor portion to the heat exchanger for vaporization whereby to cool the major portion in advance of feeding the same to the injector so as to modulate the flow of liquid refrigerant delivered by the injector, accumulating unevaporated liquid refrigerant returning from the evaporator and from the heat exchanger to provide a quantity of liquid refrigerant for recirculation, feeding said last mentioned refrigerant to the injector in surrounding relation with the nozzle thereof to supply additional refrigerant to the evaporator by the injection action of said injector, and controlling the minor portion of liquid refrigerant supplied .to the heat exchanger in accordance with variations in the quantity of unevaporated liquid refrigerant that has accumulated.

HARRY A. PHILLIPS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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