US2498017A

US2498017A - Apparatus for condensing refrigerants by evaporative cooling

Info

Publication number: US2498017A
Application number: US19931A
Authority: US
Inventors: Robert C Stutz
Original assignee: Niagara Blower Co
Current assignee: Niagara Blower Co
Priority date: 1948-04-09
Filing date: 1948-04-09
Publication date: 1950-02-21
Anticipated expiration: 1967-02-21

Description

Feb. 21, 1950 R. c. STUTZ APPARATUS FOR CONDENSING REFRIGERANTS BY EVAPORATIVE COOLING Filg ad April 9,-1948 I 2 Sheets-Sheet 1 to T 9 I i i i8 g INVENTOR. N

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fliforweys Feb. 21, 1950 R. c. STUTZ APPARATUS FOR CONDENSING REFRIGERANTS BY EVAPORATIVE coouuc 2 Sheets-Sheet 2 Filed April 9, 1948 INVEIVTQR.

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economy is eilected in the cost Patented F eb. 2I, 1950 APPARATUS FOR CONDEN SIN G REFRIGER- ANTS BY EVAPORATIVE COOLING Robert C. Stlltz, Buflalo, N.

ara Bio poration of New York Application April 9, 1948, Serial No. 19,931

21' Claims. (Cl. 62-2) This invention relates to a cooler and more particularly to a condenser for condensing refrigerating media such as ammonia, Freon, and the like in a compression refrigeration system and in which the cooling efiect utilized in such condensation is providedby the evaporation of water. However, the use of the invention is not limited to a refrigerating system and can be employed wherever it is desired to cool a gas or liquid to a point near the wet bulb temperature of the atmosphere.

One of the objects of the present invention is to provide such a cooler which is extremely compact and requires the use of a minimum of sheet metal in its construction.

Another object is to reduce the number of dampers required without sacrifice of accurate control in maintaining the most eflicient operating conditions with a minimum of maintenance.

Another object is to provide a cooler for cooling or condensing a gas or liquid, such as compressed, superheated refrigerant gas, in which the cooling water is recirculated and in which the cooling efiect is achieved principally by evaporation of the cooling water on the pipes through which the liquid or gas is conducted. By this means an of the cooling water and by its use the municipal sewer systems are not overtaxed by the installation of large refrigeration systems which normally require large amounts of cooling water for condensing the compressed refrigerant.

Another object is to provide such a cooler which is suitable for use in cooling fluids having a relatively high entering temperature. At tempera-= tures above 115 F. spray water will evaporate rapidly and deposit scale upon the pipes conducting the medium to be cooled. In accordance with the present invention the temperature of the medium to be cooled is first reduced to at or below 115 F. by air-cooling before being subjected to evaporative cooling so that any deposit which does occur is so soft as to be immediately washed off the pipes by the sprays.

Another object of the invention is to provide such a condenser in which the first or air cooling stage merely removes sensible heat from the gas to be condensed to bring it below the point at which scale would form with evaporative cooling and to remove the balance of the sensible heat and the latent heat in a second stage of evaporative cooling. By this means the preponderance of the heat is removed by evaporative cooling.

Another object is to provide such a condenser which has a relatively or to maintain this small amount of cooling to Y., assignor to Niagwer Company, New York, N. Y., a cor- 2 coils operating at high eificiency and which is comparatively inexpensive in construction.

Another object of the invention is to provide such a cooler or condenser in which the leaving temperature or head pressure of the fluid being treated can be maintained within very close limits, thereby to relieve the operator of the almost impossible job of manually balancing the condenser or cooler capacity against the compressor or other load.

Another object is to provide such a cooler or condenser which is fully automatic in maintaining the desired leaving temperature or head pressure of the fluid being treated.

Another object is to provide a simple and effective control for the minimum leaving temperature or head pressure of the fluid being treated by the adjustment of the character of the air supplied to the spray chamber.

Another aim is to provide such apparatus in which such control can be efiected entirely automatically in response to the temperature or pressure of the fluid being treated.

Another object is to provide for dewaxing the required, so as to insure the proper heat transfer between the cooling surface and the fluid being treated at all times.

Another object is to provide for heating the fluid being treated, when required to bring the fluid up to proper initial operating temperature temperature.

Another object is to prevent freezing of the spray water during cold weather.

Another object is to provide such a condenser in which the maximum amount of oil is removed from the fluid being condensed, thereby to prevent such oil from building up and caking on the heat transfer surfaces over which the fluid is subsequently passed.

Another object of the invention is to provide an oil eliminator in a condenser in which the oil is conveniently available for reuse.

Another object is to provide such an oil eliminator which does not have any moving parts other than the necessary valves to remove the oil collected therein.

Another aim is to provide such an oil eliminator which is particularly adaptable to an evaporative type of condenser.

Another object is to provide such an oil eliminator in combination with a condenser which is, without special control, self-balancing under varying load and wet bulb conditions, such selfbalancing operating to remove the maximum which is simple and inexpensive in construction;

and which will stand up under conditions of severe and constant use without getting out of order or requiring repairs. I v

Other objects and advantages will be apparent from the following description and drawings in which Fig. 1 is a side elevation, with parts broken away, of a condenser embodying the present invention.

Fig. 2 is an end elevational view viewed fro the left-hand end of Fig. 1. I

V Fig. 3 is a vertical sectional view taken on line 3-3, Fig. 1. v

Fig. 4 is an enlarged vertical section through the shell of the oil separator.

The invention is shown as embodied in a condenser having a sheet metal casing l supported on the rim of a bottom pan or tank II which forms a sump containing a body of water |2 which is evaporated to provide the cooling effect. The bottom pan or tank H is shown as extended beyond one end of the casing, as indicated at l3.

The casing l0 has.a front wall l5, a rear wall I6 and end end walls I! and t8, the latter being adjacent the extension l3 of the bottom pan'or tank Immediately above the bottom pan or tank H, the front wall l of the casing is provided with an air inlet opening l9 which extends substantially the full length of this front wall and is provided with a hoodi20 projecting forwardly from the casing and having an air inlet opening 2| in its underside. To prevent the escape of spray water from this air inlet opening 20, the sheet metal front wall 23 which engages the forward rim of the bottom pan or tank l| inclines upwardly and forwardly and immediately in rear of the air inlet opening 2| is formed with a re- 33 is a second sheet metal casing 33, this casing extending substantially the full length of the.

casing l0 and including a top wall. 36, a rear wall 36, and opposite end walls 38 connecting these top and

side walls

36, 38 with the adjacent rear wall l6 of the casing beyond the ends of the secondary air inlet opening 33 therein. Within this-casing is arranged a series of hairpin tubes 40 of a dry superheat precooling coil 4|, each havingone leg connected with an inlet header 42 and its other leg connecting with an outlet header 43. These headers are shown as arranged vertically, side by side, adjacent one end wall 33 of the casing, the inlet header 42 having at its upper end an inlet for the hot gas to be condensed and the outlet header 32 having an outlet 45 for thegases leaving the coil 4|, these inlet and outlet connections 44, 45 extending through the adjacent end wall 39 of the casing 35.

The secondary air inlet opening 33 of the easing I0 is arranged ,at the bottom of the casing 'and from the bottom of this secondary air inlet opening 33 a bottom wall 46 extends halfway across the lower otherwise open bottom of the casing 35. This bottom 46 of the casing 35 extends between the end walls 39 thereof and from he rear or outer edge of this bottom wall 46 a central partition 48 extends upwardly through the casing 35 short of the top wall 36 versely curved lip 24 which extends into the casing.

A plurality of fan housings 25 are mounted in the upper part of the casing H), the inlets of these fan housings being in communication with the interior of the casing In so as to exhaust air therefrom. A common shaft 26 extends through through the several fan housings 25 and is shown as driven by a motor 21 mounted on a bracket at one end of the casing l0. Within each fan housing 25 the shaft 26 carries a fan 28, of any suitable construction, thesefans drawing the air from the interior of the casing I0 and discharging it through outlets 29 which are directed upwardly into an .air outlet or discharge duct 3|! formed by the front, rear and end walls of the casing l0 and hence extending the full length thereof.

Air is also admitted to the upper part of the casing [6 through an inlet 33 in the rear wall l6 of the casing immediately below the fan housing 25 and extending substantially the full length of the casing. Mounted on the rear wall l6 of the thereof. ,This partition extends between the legs of the hairpin tubes 40 and it will therefore be seen that the partition 48 provides a- U-shaped passage 49 for the air, the air entering through theinlet 50 passing upwardly along the rear side of the partition 48 and thence downwardly along the inner side thereof and then passing out through the secondary air inlet opening 33 of the casing ill. In its travel through the passage 49. this air passes in heat exchange relation with the tubes of the coil 4| in the casing 35, this coil being a dry primary coil to precool and remove the superheat from the gases being condensed.

This dry primary superheat or precooling coil 4| is proportioned to remove only the superheat from the gases to be condensed and to a temperature slightly above the condensing temperature of these gases. It has been found that the gas at this temperature presents the optimum conditions for the separation of the maximum amount of oil therefrom by a simple oil separator. At higher temperatures the oil tends to remain in a volatile state and since both the gas to be condensed and a large proportion of the oil are in a vapor state; the separation through their difference in specific gravity is difiicult. At the critical tern perature of the fluid to be condensed, just above its condensing temperature, the fluid .to be condensed is in a gaseous state and the oil vapor has been condensed to a liquid state so that the separation of the maximum amount of oil from the gas can be effected in a simple oil separator.

This separator, indicated generally at 5|, is shown as comprising a cylindrical shell 52 having heads at its upper and lower ends. The outlet 45 from the superheat or dry primary cooling coil 4| is connected with an inlet pipe 53 extending tangentially through one side of the shell 52 and having its discharge end bent downwardly. The pipe 53 thereby provides a downwardly directed tangential inlet so that the entering gas, together with the entrained oil, is induced to travel in a downwardly moving helical path, thereby to set up a rotating and downpipe 84, extending through the side wall of the shell 52 near the top thereof. The inlet end of this pipe 54 is bent upwardly and arranged coaxially of the shell 52. Further to impede the escape of gas from the separator shell 52, a horizontal baille plate 58 is shown as disposed across the center of the separator shell 52, this baifle preventing any tendency of the gas to'shortcircuit from the inlet 53 to the outlet 54. In passing through the separator shell 52, the velocity of the gas is greatly reduced. particularly as the downwardly moving helically rotating column of gas is slowed almost to a standstill before it can escape in a reverse direction to the top of the separator casing. Further, the direction of movement of the gas is constantly and abruptly being changed. With such reduction in velocity and change in direction of the flow of gas, the condensed oil separates from the gas and drops to the bottom of the separator shell 52.

The level of the oil in thebottom of the separator shell 52 can be observed through a sight glass 58. When a suilicient amount of oil in the separator shell 52, as indicated by the sight glass 58, the accumulated oil can be withdrawn. For this purpose the shell 52 is provided with a drain pipe 58 having a valve 88 and is provided with another drain pipe 6| having avalve 8'2, this latter drain pipe 6| extending a substantial distance upwardly into the shell 52. In a Freon system, the drain line 58 would be connected with the crank case of the compressor. In an ammonia system, the withdrawal of oil can be through a rubber hose applied to the drain pipe 8| into a bucket. The ammonia has a lower specific gravity than the oil and hence after the oil has been drained below the level of the top of the ammonia drain line 8|, as indicated by the sight glass 58, it will be seen that any liquid ammonia in the separator can be drained by opening the drain valve 88.

From the outlet pipe 54 of the oil separator 5|, the gas passes into theinlet 65 of a secondary or condensing coil 58 arranged across the interior of the casing i8 immediately above the main air inlet l8 thereof. The tubes 88 of this coil 88 can be of serpentine form, each having its upper leg-connected with the inlet and its lower leg connected with an outlet header 18. The outlet H for the condenser coil 68 can connect with a line 12 leading to the receiver (not shown). I

To provide evaporative cooling the tubes 88 of the coil 88 are wetted from overhead spray nozzles 13. These nozzles are shown as mounted on the'ho'rizontal branches 14 of a longitudinal spray water pipe 15 which extends through the end wall |8 of the'casing l8. This horizontal spray pipe connects with the vertical outlet pipe 15 of a spray water pump'l8 which withdraws water from the body l2 in the bottom pan or tank II on which the casing I8 is accumulates header '88 from the supported. Thispump Jecting onset II, this oifset 8| extending substantially the full length of the casing l8 in front of the fan casings 25. Within this oflset 8| is arranged a spaced inner wall 82 which extends the full length of the casing l8 and which conforms to the shape of the offset 8| so as to provide a recirculation air duct 88. This recirculation air duct 83 has 'an' inlet opening 84 communicating with the outlet or discharge duct 38 at the front side thereof and has a vertical outlet opening 85 communicating with the interior of the casing I8 at 'the front side thereof and intermediate the fan housings and the eliminator plates 88.

The interior of the casing I8 is divided by a longitudinally extending vertical central partition 88 into two

vertical passages

88 and 88. The

lower edge of this partition is arranged generally in line with the top of the main air inlet opening I8 and extends upwardly to the fan housings 25. At the upper end of the passage 88 this partition forms, with the inner or rear wall 82 of the re-] circulation air duct 83, a duct 88 leading to the inlets of the fan housings 25. It will be seen that this partition 88 divides the wetted coil 58 into two parts each arranged in one of the

passages

88, 88 and further divides the stream of air entering the inlet I8 into two parts each flowing through the

corresponding passage

88, 88.

The duct 88 is shown as being capable of being closed by a pair of dampers 8| which extend the full length of the casing I8 and have their shafts 82 journalled in the end walls l1, l8 thereof. The front damper 8| is pivoted adjacent the lower edge of the inner wall not the recirculation air duct 83 and swings downwardly so as to close the 'outlet 85 of this recirculation air duct 88. It will therefore be seen that in the full line position of these dampers as shown in Fig. 3 the duct 88leading to the inlets of the fan housings 25 is fully closed and the outlet 85 from the recirculation air duct 83 is fully opened, whereas inthe opposite extreme positions of these dampers 8|, asindicated by dotted line the duct 88 leading to the inlets of the fan housings 25 is fully opened and the forward damper 8| is in a vertical position fully closing the outlet 85 of the recirculation air duct 83. In any intermediate position these dampers 8| serve to proportion the relative amounts of closure of this duct 88 and the recirculation air duct outlet 85.

These dampers8l work in conjunction with a pair of dampers 83 arranged in the air outlet or exhaust duct 38 and extending the full length of the casing M with journalled in the end walls 'il, l8 of the casing.

The front damper of this pair of dampers 83' is pivoted adjacent the opening upper edge of the inlet 84 of the recirculation air duct 83 so that when these dampers are moved into a ver- '|8 is shown as driven by an electric motor 18.

Makeup water can be supplied to this body II of water in the bottom pan or tank Ii in any usual and well known manner. plates 88 are shown as arranged above the spray nozzles 13 to remove entrained water from' the air stream. 3 1

An important feature of the invention resides in the delivery of diiferent proportions of outside air from the main air inlet l8 and recirculated or return air from the outlet duct 38. For this purpose the upper part of the front walll5 of the casing is formed to provide a forwardly pro- The usual eliminator I tical position this forward damper closes this .inlet opening 84 of the recirculation air duct 83.

It will be seen that in the horizontal full line position of these dampers, as shown in Fig. 3, the outlet of the exhaust air duct 38 is fully closed and the inlet 84 to the recirculation air duct 83 is fully opened. When these dampers 88 are moved to their opposite extreme positions, as indicated by dotted lines in Fig. 3. the outlet opening from the exhaust air duct 38 is fully opened and the forward damper 83 has been moved to fully close the inlet 84 Intermediate positioning of these dampers 83 serves to proportion the amounts of air exhausted the end of their shafts 84 of the recirculation air duct 83.

through the duct an or recirculated through therecirculation air duct 33.

The dampers 3i and 03 operate in conjunction withone another these dampers moving from the full line positions shown in Fig. 3 to the dotted line positions also shown in this figure in unison.

95 fast to the end of each damper shaft 9| iour-;

nalled in the end wall I1, the outer ends of these arms 95 being interconnectedby a link 95. Thecorresponding -projecting ends of the damper shafts 92 are also each fast to an arm 90, the free ends of which are connected by a link 99. An operating, lever I is shownas pivoted at its center, as indicated at IN, to the end wall I1 and as having its upper end connected by a link I02 with the rear end of the link 96 and as connected at its lower end by a link I03 with the rear end of the link 99. This operating lever I00 is shown as actuated by an electric damper motor I04 suitably mounted on the end wall I! of the casing and shown as having a swinging operating arm I05 connected by a link I05 with the operating lever I00 to actuate the same. It will be seen that when the operating arm I05 of this damper motor I04 is swung counterclockwise as viewed in Fig. 2, the operating lever I00 is swung counterclockwise to move th arms 95 clockwise and to swing the forward arm 98' clockwise and the rear arm 93 counterclockwise. This movement swings the dampers 93 and 9| from the full toward the dotted line positions shown in Fig. 3.

The condenser is automatically-controlled, and for this purpose a controller I08 is mounted on the condenser outlet line with its sensitive parts immersed in the fluid passing therethrough. This controller is preferably in the form of an electrical pressure switch which is responsive to variations in head pressure in the line I2 but it will be understood that this controller could be a thermostat. This pressure switch is connected to one side I09 of an electric line and by a line I I0 with the electric damper motor I0l. Another line III from the pressure switch I03 connects with the motors 21 and I9, the other terminals of which are connected with the other side I I2 of the main power line. This pressure switch I08 is set to maintain the lowest practical operating pressure. Through the line IIO it operates the damper motor I04 which in turn positions the dampers M and 93 to balance 'the proportion of fresh and recirculated air passing through the spray chamber against the refrigeration load. If the fresh air temperature is cold or the load drops off, the pressure switch I08 automatically raises the amount of recirculated air returned to the spray chamber through the recirculation air duct 83. When, under no-load or extreme weather conditions, the dampers 9| and 93 completely close the ducts 30and 90, respectively, th pressure switch I08 through the line III de-energizes the fan motor 21 and the spray pump motor 19.

In addition, safety features are provided which include an additional safety pressure switch or thermostat II3 which is mounted on the liquid refrigerant outlet line 12, and with its sensitive parts responsive to the pressure or temperature of th liquid refrigerant passing through. This safety pressure switch H3 is set a few pounds higher than the control switch I03. This safety switch is connected with the side I09 of the power inseam? I line and alsowith the line In to the

electric motors

21 and 10. If the outside dampers 93 are frozen shut the. safety switch I I3 operates to start the'fan motor 20 and spray pump motor 19, thereby to recirculate airthrough the casing until the dampers are freed when the normal con-. trol switch I03 takes over again. As an additional safety features small electric immersion heater H5 is preferably disposed in the bottom pan or tank II so as to keep the spray'water I2 therein from freezing during no-load condition in winter.

This immersion heater can be under control of a thermostat H6, also immersed in the body I2 of spray" water and connected with the immersion heater through a control line II8.

Operation In the operation of the apparatus as above described, and assuming the dampers 9| and 93 to be in the dotted line position shown in Fig. 3, and hence in a position in which the ducts 30 and are open and the recirculation duct 83 completely closed off, two streams of atmospheric air are drawn into the casing I0 by the fan wheels 28 and discharged through the outlet or exhaust duct at the top of the casing I0.

One of these air streams enters the casing 35 through the inlet 50 and travels up and then down the U-shaped passage 49 provided in this casing by the partition 48 and thence is drawn into the casing I0 through the air inlet opening 33. This air stream passes the tubes 40 of the dry primary or superheat precooling coil AI and thereby cools the gas which enters this primary coil at 44 and leaves at 45. This primary or superheat cooling coil 4| is proportioned to remove the superheat from the gas to be condensed and to cool it to a form of a gas and at a temperature slightly above its condensing temperature.

At this temperature it has been found that the maximum amount of oil can be separated from the fluid to be condensed. In cooling the gas to be condensed to this temperature slightly above its condensing temperature, the oil vapor in the gas is condensed so that it isin liquid-form. At the same time the fluid to be condensed is still in the form of a gas so that the separation is of a liquid from a gas and not of a liquid from a liquid as would be the case if the temperature of the gas to be condensed were permitted to fall below its condensing temperature.

To separate the entrained liquid oil from the gas to be condensed, it passes from the outlet 45 of the primary dry superheat cooling coil M to the tangential and downwardly directed inlet 53 extending through the cylindrical shell 52 of the oil separator 5i. The inlet velocity sets up a downwardly moving and rotating column of gas in this separator shell, the gas from which escapes upwardly in opposition to this downwardly moving column. In so escaping the gas passes around the battle 56 and thence through the upwardly directed central inlet of the outlet pipe .the Outlet duct 38. The

the inlet air entering the hood "8. this coil being arranged in the casing .18 and across the divided stream of air flowing upwardly on opposite sides of the partition 88. This air enters the main air inlet opening 2| oi the hood 28 and flows through the inlet opening I8 into the shell I8. This air stream is then divided into two parts by the partition 88, one part flowing upwardly through the passage 88 and the other part flowing upwardly through the passage 88,

both parts passing in contact with the tubes 88 of the wetted condensing coil 88. The part passing up through the passage 88 passes the spray nozzles I3 and eliminator plates 88 directly into the inlets of the fan casings to be discharged directly through the now open exhaust outlet oi part of this air stream flowing upwardly through the passage 88 passes the spray nozzles I3 and eliminator plates 88 and thence passes through the now open duct 88 into the inlets of the fan casings 25 also to be discharged through the now open exhaust outlet of the outlet duct 38.

The entire condensing coil 88, arranged in the passage 88 arranged in the passage 88, is sprayed with water withdrawn from the body I! of water in the bottom pan or sump II supporting the casing'IIi by the spray water pump I8 which delivers this water to the horizontal spray pipe 15 andits branches N. This water is discharged downwardly by the nozzle I3 against the tube 88 of the condenser coil 88 thereby to wash these coils and maintain them in a wetted condition.

The cooling of the fluid passing through the wetted condensing coil 88 is thereby eifected essentially by the evaporation of the water sgrayed on these coils. At the same time, the flui being treated has been cooled to such an extent on passing through the dry primary superheat precooling coil 4I that there is no tendency for scale to form on the condensing coil- 88 from the water sprayed thereon. By employing evaporative cooling with the condensing coil 88, this coil has many times the cooling capacity of a dry surthat is, that part face cooling coil of the same size. Further, since an evaporative cooling coil operates in response to the wet bulb temperature of the outside air, and since, under normal conditions, the wet bulb temperature of the outside air is substantially lower than its dry bulb temperature, the condensate leaves at a very much lower temperature. This condensate leaves the outlet header I8 of the secondary evaporative cooling coil 68 through the outlet line 72 through which the condensate is conducted to the usual receiver (not shown).

In so passing through the outlet line 12, the condensate contacts the sensitive parts of the pressure switch I88. When the head pressure oi this condensate drops below the setting of this pressure switch I88, this switch, through the electric line IiI, operates the electric damper motor I84 to move the dampers 8i and 83 from the dotted line position shown in Fig. 3 toward the full line positions there shown. When this occurs. the inlet 84- and outlet 85 of the recirculation air duct 83 are opened to a correspond ng extent and a part of the air discharged into the exhaust duct 38 by the fan wheels 28. flows through '84 of the recirculation air duct 83 and through its outlet 85 into the upper end of the passage 88. This air from the outlet 85 of the recirculated air duct 83 joins the air entering the duct 98 past the partly opened dampers 8|. This air is supplied from the main air inlet hood 28, this inlet 2| and casing inlet as well as that part temperature and I8 into the bottom 01' the casing I8 and being divided into two parts by the partition 88, one part flowing up the passage 88 past the wetted tubes of the condenser coil 88, spray nozzles I8, eliminator plates 88 and through the duct 88 into the inlets of the fan housings 28, and the other part flowing up the passage 88 past the wetted tubes of the condenser coil 88, spray nozzles I8, and eliminator plates 88 to the inlets of the tan housings 28. Since with the dampers 8| and 83 moved partly away from their vertical positions a part of the air handled by the fan wheels 28 is recirculated air, it is apparent that less fresh air is drawn into the casing I8 and since the cooling effect is provided by the evaporation of water by the stream of fresh air drawn into the casing, it is apparent that the efl'ective cooling of the condenser is reduced.

It the head pressure i the 'outlet line 12 continues to rise the pressure switch I88, through the damper motor I84, continues the movement 01' the dampers 8| and 83 toward their horizontal positions. When these dampers reach approximately 10 of their horizontal position, the principal amount of the air from the outlet 85 of the recirculated air duct 83 no longer passes directly to the duct 88 but flows downwardly through the passage 88 along the front wall I5 of the casing and joins the stream of air flowing in through the inlet I8 from the hood 28. A part of this recirculated air, of course, joins the air stream flowing upwardly through the passa e 88 but as this stream has been largely cut off by the almost horizontal dampers 8i, the preponderance of the recirculated air so flowing down the front casing wall I5 joins the stream or air flowing up the passage 88. Since this recirculation air passing through the recirculated air duct 83 has'been heated by passing the precooling coil II and the secondary condenser coil 88 and also is substantially saturated with the moisture in passing over the exterior of the wetted condenser coil 88 and through the sprays from the nozzles I3, it will be seen that the mixed fresh and recirculated air now supplied to the bottom of the casing I8 has a higher wet bulb temperature and hence the evaporative cooling effect of the water and air in passing over the wet condenser coils 88 is reduced.

It will therefore be seen that the pressure switch I88 maintains a constant minimum head pressure and temperature of the condensate leaving the condenser through this outlet line I2 by the operation or the dampers 8| and 83, a falling head pressure of the condensate moving these dampers to provide a greater pro ortion of recirculated air and a lower proportion of fresh air. This modulating control of the dampers 8| and 83 allows the intermediate position of these dampers to hold a constant minimum temperature and head pressure of the condensate by the use of recirculated air and cold fresh air. The recirculation of the necessary amount of air 38 to the bottom of the casing I8 in so maintaining a constant minimum temperature and head pressure of the condensate also keeps the amount .of evaporated moisture at a minimum.

If a condition of no-load, or extreme weather condition, causes the pressure switch I88 to move the dampers 83 to the horizontal full line position shown in Fig. 3 in which no air is discharged from the casing and all of the air therein is recirculated, the pressure switch 188 closes the circuit through the electric line III to the fan from the air discharge duct motor and the spray water pump motor 19. This de-energizes these motors so as to cut the condenser out of operation as an evaporative type of condenser.

As an additional safety feature. if the dampers 93 should become frozen shut in winter operation, and the head pressure in the outlet line 12 rises in calling for evaporative cooling the safety switch H3, which is set a few pounds higher than the control pressure switch I08, will establish a circuit through the line ill to. energize the fan motor 21 and the s ray pump motor 19. Hot air is thereby recirculated through the casing l until the dampers 93 are freed when the control pressure switch I 08 again takes over control, as above indicated.

As a further safety feature, to prevent freezing of the spray water 12 in winter operation under no-load condition, this spray water is heated by the immersion heater H under control of the thermostat HG which is setto establish a circuit through this immersion heater when the temperature of the body of spray water I 2 p to the freezing point. Further, this heater can be used to dewax the condenser coil 68 by holding the dam ers 9| and 93 to recirculate the air and bv ener izing the immersion heater H5 so as to heat the air and water bein recircu- 1a.:v to a temperature sufllcient to melt the wax in the coil 68.

30 From the foregoing it will be seen that the present invention provides a cooler in which the cooling efl'ect is provided principally by the evaporation of water and in which the cooling effect is balanced against the load by the recirculation of air through the s rayed coils. Itwill also be seen that by providing the short recirculation air duct 83 as shown. the cooler is very much more compact and reouires less sheet metal as com-- pared with a structure where the recirculation duct connects with the main air inlet hood 20. Further. the controller can be set to maintain the lowest practical operating pressure of the refrieeration system; full safety provisions are made against the danger of freezin in cold weather; danger of scaling or incrustation on the wetted coil is eliminated; and maximum oil separation is effected in a simple oil se arator and in a manner permitting convenient return to the compressor.

1. A heat exchange dev ce for cooling a stream 01' fl id, compri ing a casing formin a chamber having an air inlet at one end and having at its oppos te end an air outlet duct provided with an air outlet. a fan arran ed w thin said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct. a cooling coil for said stream of fl id arranged between said air inlet and fan in the stream of air passing through said chamber, means arran ed to discharge and distribute w ter over s id coolin coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom. a partition in said casing extending from said fan toward said one end of sa d casing and dividing said easing into two air passages divid n said air stream enter ng said fan into two arts and e ch pa sage containing a part of said cooling coil, wal s forming a recirculation air duct having its in et end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, and dampers regulating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct.

2. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exteriorof said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, a wall arranged within said casing and forming therewith a recirculation air duct having its inlet end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, and dampers regu-' lating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct.

3. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber; means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said easing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a recirculation airduct having an inlet at one end opening into said outlet duct and having an outlet adjacent said fan opening into one of said chambers and said walls also forming a fan inlet 50 duct adjacent said recirculation air duct outlet and leading from said one of said passages to said fan, at least one damper movably arranged to close said recirculation air inlet as it opens said outlet of said outlet duct and vice versa, and

55 at least one other damper movably arranged to close said recirculation air outlet as it opens said fan inlet duct and vice versa.

4. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber 00 having an air inlet at one end and having at its opposite end an an outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air through 5 said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into 7 two parts and each passage containing a part of air outlet, a fan having an air inlet at said cooling coil, walls forming a; recirculation air duct having an inlet at one end opening into said outlet duct and having an outlet adjacent said fan opening into one of said chambers and said walls also forming a tan inlet duct adjacent said recirculation air duct outlet and leading from said one of said passages to said fan, at least one damper movably arranged to close said recirculation air inlet as it opens said outlet of said outlet duct and vice vers at least one other damper movably arranged to close said recirculation air outlet as it opens said i'an inlet duct and vice versa, and'means interconnecting said dampers to move them simultaneously to close said recirculation air duct and vice versa.

5. A heat exchange device for cooling a, stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a, fan arranged within said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a recirculation air duct having its inlet end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged from sa d out et duct through its outlet and through said recirculation air duct, and a controller responsive to one of said streams and regulating said dampers.

6. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an arranged within said casing to of air through said inlet and discharge said stream of air draw a stream chamber and to through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts, and each passage containing a part of said cooling coil, walls forming a recirculation air duct having its inlet end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct, and a controller responsive to the temperature of one of said streams and regulating said dampers.

'7. A heat exchange of fluid, comprising a casing forming a chamber one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream of air through said inlet and device for cooling a stream stream of fluid arranged between chamber and to discharge said stream 01 air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward. said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a re-,

circulation air duct having its inlet end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct, and a controller responsive to the pressure of said fluid passing through said cooling coil and regulating said dampers.

8. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passin through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a recirculation air duct having an inlet at one end opening into said outlet duct and having an outlet adjacent said fan opening into one of said passages and said walls also forming a fan inlet duct adjacent said recirculation'air duct outlet and leading from said one of said passages to said fan, at least one damper movably arranged to close said recirculation air inlet as it opens said outlet of said outlet duct and vice versa, at least one other damper movably arranged to close said recirculation air'outlet as it opens said fan inlet duct and vice 'versa, and a controller responsive to one of said streams and regulating said dampers to move them simultaneously to close said recirculation air duct and vice versa.

9. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber havin an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream' of air through said inlet and chamber and to discharge said stream of air through said outlet duct, a cooling coil for said said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said'cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a refan toward said one end of r let adjacent said fan opening into one of said passages and said walls also forming a fan inlet duct-adjacent said recirculation air duct outlet and leading from said'one of said passages to said fan, at least one damper movably arranged to close said recirculation air inlet as it opens said outlet of said outlet duct and vice versa, at least one other damper movably arranged to close said recirculation air outlet as it opens said fan inlet duct and vice versa, and a controller responsive to the temperature of one of said streams and regulating said dampers to move them simultaneously to close said recirculation air duct in response to a rising temperature of said one of said air streams and vice versa.

10. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a'tan arranged within said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said easing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a recirculation air duct having an inlet at one end opening into said outlet duct and having an outlet adjacent said fan opening into one of said passages and said walls also forming a fan inlet duct adjacent said recirculation air duct outlet and leading from said one of said passages to said fan, at least one damper movably arranged to close said recirculation air inlet as it opens said outlet of said outlet duct and vice 'versa, at least one other damper movably arranged to close said recirculation air outlet as it opens said fan inlet duct and vice versa, and a controllerresponsive to the pressure of said stream of fluid passing through said cooling coil and regulating said dampers to move them simultaneously to close said recirculation air duct in response to a rising pressure oi. said stream of fluid and vice versa.

11. A heat exchange device for cooling a stream of fluid, comprising a casing forming a. chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream of air through said inlet and chamher and to discharge said stream of air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending having an outlet adlacent said Ian opening into one of said passages and said wall also forming a ran inlet duct alongside said recirculation duct leading from said one of said passages to said fan, -a damper mounted in said outlet duct to I,

swing about an axis adjacent one oi'its edges and arranged generally parallel with and adjacent to that edge of said inlet of said recirculation duct remote from said fan whereby said damper closes said recirculation air inlet as it opens said outlet of said outlet duct and vice versa, another damper arranged in said one of said passages to swing about an axis adiacent one of its edges and arranged generally parallel with and adjacent to that edge of said wall forming the outlet oi said recirculation air duct and the inlet of said tan inlet duct whereby said another damper closes said outlet of said recirculation air duct as it opens said inlet 01 said Ian inlet duct and vice versa, and means interconnecting said dampers to move them simultaneously to close said recirculation air duct and vice versa.

12. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an an outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream Of air through said inlet and chamber and to discharge said stream of air through Said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream oi air passing through said chamber,

means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorbheat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said easing into two air passages dividing said air stream entering said Ian into two parts and each passage containing a part of said cooling coil, walls forming a recirculation air duct having its inlet end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged .from said outlet duct through its outlet and through said recirculation air duct, a dry precooling coil, means arranged to pass air over said dry precooling coil, and means arranged to pass said stream of fluid through said dry precooling coil prior to its passage through said first cooling coil.

13. A heat exchange device for cooling a stream 01 fluid, comprising a casing forming a chamher having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged within said casing to draw a stream of air through said inlet and chamber and to discharge said stream of air from said fan toward said one end of said casing and dividing said easing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said coolin coil, a wall arranged within said casing and forming therewith a recirculation air duct arranged alongside said fan and having an inlet at one end opening into said outlet duct and through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a recirculation air duct having its inlet end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct, said casing being provided with a second air inlet, a dry precooling coil in the path of the stream'of air entering said second air inlet,and means-arranged to pass said stream of fluid through said dry precooling coil prior to its passage through said first cooling coil.

14. A heat exchange device for cooling a stream of fluid, comprising a casing forming a chamber having an air inlet at one end and having at its opposite'end an air outlet duct provided with an one end of said casing air outlet, a fan arranged within said casing'to draw a stream of air through said inlet and chamher and to discharge said stream of air through said outlet duct, a cooling coil for said stream of fluid arranged between said air inlet and fan in the stream of air passing through saidchamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said' cooling coil, walls forming a recirculation air duct having its inlet end opening into said outlet duct precooling coil in the path of entering saidsecond air inlet and proportioned to densing temperature thereof 1 dense said higher boiling separator, and conduits arranged to pass a stream and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct, said casing being provided with a second air inlet leading to the other of said passages, a

diy precooling coil in the path of the stream of air entering said second air inlet, and means arranged to pass said stream of fluid through said dry precooling coil prior to its passage through said first cooling coil.

15. A condenser for gases containing a higher boiling point vapor, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a fan arranged to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct, a cooling coil arranged between said air inlet and said fan in the stream of air passing through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior of said cooling coil and to evaporate and absorb heat therefrom, a partition injsaid casing extending from said fan toward said one end of said casing and dividing said casing into two air passages dividing said air stream entering said fan into two parts and each passage containing a part of said cooling coil, walls forming a recirculation air duct having its inlet end opening into said outlet duct and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct, a dry precooling coil proportioned to remove the superheat from said gas and to reduce its temperature close to and above the condensing temperature thereof, and a liquid separator, and conduits arranged to pass a stream of the gas to be condensed in series from said dry precooling coil and-through said liquid separator and said cooling coil wetted by said stream of water.

16. A condenser for gases containing a higher boiling point vapor, comprising a casing forming a chamber having an air inlet at one end and having at its opposite end an air outlet duct provided with an air outlet, a 'fan arranged to draw a stream of air through said inlet and chamber and to discharge said stream of air through said outlet duct,

a cooling coil arranged between said air inlet and said fan in the stream of through said chamber, means arranged to discharge and distribute water over said cooling coil to wet the exterior -of said cooling coil and to evaporate and absorb heat therefrom, a partition in said casing extending from said fan toward said and dividing said casing into .two air passages dividing said air stream entering -said fan into two parts and each passage containing a part of said cooling coil, walls forming a recirculation air duct having its inlet end opening 1 into said outlet duct and its outlet end opening adjacent said fan into one of said passages, dampers regulating the proportion of air discharged from said outlet duct through its outlet and through said recirculation air duct, said casing being provided with a second air inlet, a dry the stream of air remove the superheat from said gas and to reduce its temperature close to and above the conand thereby to conpoint vapor, a liquid of the gas to be condensed in series from said dry precooling coil and through said liquid separator and said cooling coil wetted by said stream oi water. v

, 17. A heat exchange device for maintaining a .fluid in a selected temperature range determined i by the character of the-fluid, and preventing the temperature from falling below said range, comprising a casing forming a chamber having an air inlet and an air outlet, a fan arranged to force a stream of air from said inlet, through said chamber and out through said outlet, a cooling coil arranged in' said chamber in the stream of air passing through said chamber, means arranged to continuously conduct the said stream] of fluid to be cooled through said cooling coil, means for discharging and distributing a stream of water over said cooling coil to wash the exterior of said cooling coil and to evaporate thereon and absorb heat therefrom, said streams of water and air being normally heated through heat derived from said stream of fluid passing through said cooling coil, air recirculation means arranged to conduct at least a part of the stream of air leaving said chamber back to said chamber and again contact said cooling coil, means responsive to the condition of one of saidstreams and arranged to adjust the amount of air so conducted back by said air recirculation means to prevent the temperature of said fluid in said cooling coil from falling below said temperature range, a dry precooling coil, means arranged to pass air over said dry precooling coil, and a conduit arranged to pass said stream of fluid from said dry precooling coil through said first cooling air passing I discharging and distributing a stream of water over said cooling coil to wash the exterior of said cooling coil and to evaporate thereon and absorb heat therefrom, said streams of water and air being normally heated through heat derived from said stream of fluid passin through said cooling coil, air recirculation means arranged to conduct at least a part of the stream of air leaving said chamber back to said chamber to again contact said cooling coil, means responsive to the temperature of one of said streams and arranged to adjust the amount of air so conducted back by said air recirculation means to prevent the temperature of said stream of fluid passing through said cooling coil from falling below said temperature range, said casing being provided with a second air inlet, a dry precocling coil in the path of the stream of air entering said second air inlet, and a conduit arranged to pass said stream of fluid from said dry precooling coil through said cooling coil 'wetted by said stream of water. I 19. A heat exchange device for maintaining a fluid in a selected temperature range determined by the character of the fluid, and preventing the temperature from falling below said range, comprising a casing forming a chamber having an air inlet and an air outlet, a fan arranged to force a stream of air from said inlet, through said chamber and out through said outlet, a cooling coil arranged in said chamber in the stream of air passing through said chamber, means arranged to continuously conduct the said stream of fluid to be cooled through said cooling coil, means for discharging and distributing a stream of water over said cooling coil to wash the exterior of said cooling coil and to evaporate thereon and absorb heat therefrom, said streams of water and air being normally heated through heat derived from said stream of fluid passing through said cooling coil, air recirculation conduits arranged to conduct at least a part of the stream of air leaving said chamber back to said chamber to again contact said cooling coil, a heater arranged to apply heat to said stream of water and to said stream of fluid passing through said cooling coil, means responsive to the temperature of one of said streams and arranged to adjust the amount of air so conducted back by said air recirculation means and also to adjust said heater to prevent the, temperature of said stream of fluid passing through said cooling coil from falling below said temperature range, a dry precooling coil, and a conduit arranged to pass said stream of fluid from said dry precooiing coil through said cooling coil wetted by said stream of water.

20. A condenser for gases containing a higher boiling point vapor, comprising a casing forming a chamber having an air inlet and an air outlet, a fan arranged to force a stream of air from said inlet, through said chamber and out through said outlet, a cooling coil arranged in said chamber in the stream of air passing through said chamber, means for discharging and distributing a stream of water over said cooling coil to wash the exterior of said cooling coil and to evaporate thereon and absorb heat therefrom, said streams of water and air being normally heated through heat derived from said cooling coil, air, air recirculation means arranged to conduct at least a part of the stream of air leaving the chamber back to said chamber to again contact said cooling coil, a dry precooling coil, proportioned to remove the superheat from said gas and reduce its temperature close to and above the condensing temperature thereof, a liquid separator, conduits arranged to pass a stream of the gas to be condensed in series from said dry precooling coil and through said liquid separator and said cooling coil wetted by said stream of water, and means responsive to the condition of one of said streams and arranged to adjust the amount of air so conducted back by said air recirculation means to prevent the temperature of said stream of gas passing through saidcooling coil wetted by said stream of water from falling below said temperature range. l

21. A condenser for gases containing a higher boiling point vapor, comprising a casing forming a chamber having an air inlet and an air outlet, 8. fan arranged to force a stream of air from said inlet, through said chamber and out through said outlet, a cooling coil arranged in said chamber in the stream of air passing through said chamber, means for discharging and distributing a stream of water over said cooling coil to wash the exterior of said cooling coil and to evaporate thereon and absorb heat therefrom, said streams of water and air being normally heated through heat derived from said cooling coil, air, air recirculation means arranged to conduct at least a part of the stream of air leaving the chamber back to said chamber to again contact said cooling coil, a dry precooiing coil proportioned to remove the superheat from said gas and reduce its temperature close to and above the condensing temperature thereof, a liquid separator, conduits arranged to pass a stream of the gas to be condensed in series from said dry precooling coil and through said liquid separator and said cooling coil wetted by said stream of water, a heater arranged to apply heat to said stream of water and to said stream of fluid passing through said cooling coil washed by said stream of water, and means responsive to the temperature of one of said streams and arranged to adjust the amount of air so conducted back by said air recirculation means and also to adjust said heater to prevent the temperature of the stream of gas passing through said cooling coil from falling below said temperature range.

' ROBERT C. STUTZ.

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

UNITED STATES PATENTS Number Name Date 2,379,932 Schoeplin July 10, 1945 2,445,199 Williams July 13, 1948