US 2990695 A
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Description (OCR text may contain errors)
y 4, 1961 D. A. LEFFINGWELL, JR 2,990,695
THERMODYNAMIC TRANSFER SYSTEMS 2 Sheets-Sheet 1 Filed Oct. 6. 1958 INVENT OR. DWIGHT A. LEFFINGWELL JR uvu) ATTORNEY FIG. 2
July 4, 1961 D. A. LEFFINGWELL, JR 2,990,695
THERMODYNAMIC TRANSFER SYSTEMS Filed 001:. 6, 1958 2 Sheets-Sheet 2 INVENTOR.
DWIGHT A. LEFFINGWELL JR ATTORNEY 2,990,695 7 THERMODYNAMIC TRANSFER SYSTEMS Dwight A. Leifingwell, Jr., Davenport, Iowa, assignor to The Bendix Corporation, a corporation of Delaware Filed Oct. 6, 1958, Ser. No. 765,399
9 Claims. (Cl. 62--223) This invention relates to thermodynamic transfer systems and particularly to breathing and ventilating systems for substantially sealed enclosures such as suits, capsules, and similar enclosures employed to protect humans in contamination or non-supportive environments.
Humans generate heat, moisture and carbon dioxide, all of which must be removed from such enclosures if they are used for more than very short periods and an object of this invention is to provide improved and novel means for the removal of heat, moisture, and carbon dioxide, and all of these, from such enclosures.
Another object is to provide means for such removal which will be operative over prolonged periods of time at high efficiency with apparatus of minimum weight and bulk, and which may be completely portable.
Another object of the invention is to supply respiratory gas and to condition the atmosphere in an enclosure to maintain its occupant reasonably comfortable although he expends great amounts of energy.
Certain of these objects are realized bythe provision of heat exchangers in which cool respiratory gas is added to the enclosed atmosphere to remove body heat and moisture from the circulating atmosphere. It is a feature possible within the invention that body moisture is not merely condensed but is turned to frost and then melted. Advantageously, two heat exchangers are used and alternately connected to freeze body moisture and to defrost, resulting in continuous high efiiciency in heat exchange surface.
Another object of the invention is to provide an improved heat exchanging means for thermodynamic transfer systems and particularly to provide a dual section heat exchanger, each section of which includes a heat adsorbing phase and a heat releasing phase, and means for connecting one phase of each exchanger in the system and for alternately connecting the other phase of each exchanger section in the system. 1
Thus in a refrigeration system including both a condenser and an evaporator, a dual section condenser or evaporator, or both, are employed. One phase of both sections of this heat exchanger is permanently connected in the circuit and the other phase of one and then the other of said sections is alternately connected in the circuit. Thus if a dual section condenser is employed, the
heat adsorption phase, which may comprise radiating tates Patent C) fins, of both sections may be exposed to the medium to operation. But the heat dissipation phase of the other exchanger section is not so connected. Its fins are connected to the heat adsorbing medium so that the fins are cooled whereby the section is returned to its original condition of high efficiency. By alternate connection to include a rejuvenated heat exchanger section the average efliciency of the system is raised and made more uniform with time.
While not limited to suits, a particularly advantageous form of the invention includes a suit and this form has pirator and atmosphere conditioning unit shown schematically;
FIG. 2 is a schematic view of the respirator and atmosphere conditioning taken on line 2-2 of FIG. 1 including a fragment of the suit;
FIG. 3 is a diagram of a system like that shown in FIGS. 1 and 2; and
FIG. 4 is a schematic view in section of the two inlet and single outlet, three-way valve employed in FIGS. 1 and 2.
Another object of the invention is to provide an improved integrated suit and respiratory and suit atmosphere conditioning system.
Other objects and advantages will hereinafter be apparent from the description of the embodiment of the invention selected for illustration, it being understood that various modifications may be'made in the embodiment illustrated and that other embodiments are possible Without departing from the spirit of the invention or the scope of the appended claims.
The invention contemplates the use of an enclosure such as a suit, capsule, or other enclosure sealed against toxic fumes, water, vacuum, or other dangerous environment in which the enclosure is disposed. The latter will be made of 'acid resistant, insulated, and otherwise suitable material to withstand the external conditions to which it is subjected. The invention is concerned with providing respiratory gas to the occupant of the enclosure, removal of the carbon dioxide generated by his breathing, removal of his perspiration and removal of the 700 to 1400 B.t.u.s per hour of metabolic heat which is generated by human beings depending upon the degree of their activity.
Such an enclosure is represented by the numeral 10 in FIG. 3 of the accompanying drawing. The enclosure has an inlet 11 and an outlet 12 both of which are connected to a housing 13 including a partition 14 which, together with the side walls of the housing, define a central area containing a two inlet and single outlet, three-way valve or alternator 15, a control valve 16 and a Venturi pump 17. Heat exchangers 20 and 21 are disposed in the spaces between said central area and the side walls of enclosure 13, respectively, whereby gas, flowing into enclosure 10 by way of inlet 11 and out of enclosure 10 by way of outlet 12, is divided so that some of the gas flows past each of heat exchangers 20' and 21, whereafter all of the gas is aspirated into Venturi pump 17 from whence it emerges from the pump outlet 22 to flow through inlet 11 back to enclosure 10. This movement of gas is illustrated in FIG. 3 by the dotted lines. Some of the gas is discharged from enclosure 10 through an opening 24 controlled by a check valve 25.
The gas which leaves the enclosure at outlet 24 is replaced by fresh respiratory gas entering the gas flow stream at the injector 26 of aspirating pump 17. This gas is supplied from an external source, entering by an inlet line 30 connected to the lower end of both of heat exchangers 2.0 and 2.1. The tops ends of the heat exchangers are connected to inlet ports of valve 15 whose single outlet is connected to the control valve 16. The outlet of valve 16 is connected to injector nozzle 26 of the Venturi pump 17 whose Venturi is designated 27 and I whose aspirating inlet is numbered 28.
been selected for illustration in the accompanying drawing 3 wherein:
FIG. 1 is a view taken on line 1-1 of FIG. 2 of apparatus embodying the invention including a fragment of a suit, a liquid-gas converter shown in elevation, and a rcs- Advantageously the respiratory gas source comprises a liquid-gas converter such as the conventional converter system 3 1, which may comprise, as shown, a double walled insulating vessel 32 for liquid respiratory fluid having a lower outlet 33 connected to inlet 30 and a filling line 34 controlled by a valve 35. Outlet 33 is further connected, by a line 36 to a warming and evaporating coil 37 connected in series with a pressure opening valve 38 and a three-way build-up and vent valve 39 to an upper opening to the gas phase of vessel 32.
Valve 39 may be operated to vent the gas phase of vessel 32 to atmosphere when valve 35 is opened and the vessel is being filled with liquid respiratory gas. Otherwise valve 39 is operated to complete the connection from vessel 32 to coil 37 through the pressure closing valve 38. Liquid trickling through outlet 33 and .into line 36 is warmed and evaporated at coil 37. The vapor passes through valves 38 and 39 to the space within vessel 32 above the level of the liquid therein contained; this space is called the gas phase of the container. This process continues until pressure in the gas phase has reached a -pre-determined value suflicient to close valve 38.
This pressure in the gas phase of the vessel is adequate to force liquid through opening 33and inlet 30 to the heat exchangers or evaporators 20 and 21. Liquid in the heat exchanger is warmed, evaporated, and expanded by the circulation of gas through enclosure and over the heat exchanger. If valve is adjusted to connect heat exchanger 21 to valve 16, the gas generated in exchanger .21 will flow through valves 15 and 16 and through the jet nozzle 26 toward the Venturi 27, aspirating with it the gas adjacent aspirating opening 28 whereby the gas flow indicated by the dashed lines is effected.
Perspiration of the occupant of enclosure 10 will evaporate to the gas flow and be carried down over heat exchangers 20 and 21 condensing there to form frost on the heat exchanger 21. During this period respiratory gas evaporated in heat exchanger 20 is stagnant because its upper end is closed by valve 15. When a coating of frost has been formed on exchanger 21, valve 15 is operated to disconnect exchanger 21 from and connect heat exchanger 20 to control valve 16 and the jet nozzle 26. Thereafter the frosted perspiration will form on heat exchanger 20. The warm gas emerging from enclosure 10 through outlet 12 and flowing over heat exchanger 21 will melt the frost and the condensate will collect in trap 40 at the bottom of housing 13. Check valve 25 is adjusted to maintain a pressure within enclosure 10 suitable to its occupant and higher than the pressure of the am.- bient atmosphere. Trap 40 is adjusted, in length, so that the condensate acts to preserve this pressure difference; any condensate beyond what is needed for this purpose being discharged automatically to the ambient atmosphere or collected.
Valve 15 alternately connects heat exchangers 20 and 21 to control valve 16 sufficiently frequently so that the frost coating on the heat exchangers is never so great as to impair their effectiveness. Control valve 16 is arranged to provide a minimum flow suflicient when added to the gas circulating through the system to maintain the carbon dioxide content of the gas at a selected low level suitable to human physiological needs. Such additional respiratory gas is permitted to flow through control valve '16 as is required for effective removal of body heat. Ad-
vantageously the valve is made sensitive to temperature of the gas circulating through the enclosure 10. If the users activity is increased, hisbody'heat, perspiration, and carbon dioxide generation are increased. Among these variables temperature is easily sensed, and'is sensed as best shown in FIGS. 1 and 2, for control of'valve 16 to increase the rate of flow of fresh respiratory gas.
'InFIG. 1 there is shown a suit suitable for use in connection with the invention comprising an outer impermeable layer 50 and an inner permeable layer 51. The suit includes a helmet portion having a transparent window '52 and gas outlets 53 arranged so that escaping gas is directed over the window 52 whereby to prevent fogging of the-window. Flexible flaps 54 at outlet openings 53 act as check valves.
At the back of the .suit.is .a housing.55:including central partitions 56 whichtogether with the side ,walls 57 and 58 of the housing 55 form passages for circulating gas. A heat exchanger 59, comprising a reflexed coil 60 and conducting fins 61, is disposed in one of these passages and a similar heat exchanger 65, comprising reflexed coil 66 and conducting fins 67, is disposed in the other pasage. The lower ends of coils 60 and 66 are connected together to a common inlet 68.
The upper ends of the coils extend through the partitions 56 to a two inlet and single outlet, three-way valve 70 disposed between the air passages at the top of housing 55. The outlet of the valve 70 is connected to the inlet of control valve 71 whose outlet is connected to the jet nozzle 72 of a Venturi pump having an aspirating inlet 73 and a Venturi 74 and housing outlet 75 is connected to the suit intermediate layers 50 and 51.
Valves 70 and 71 are specific forms of the valves 15 and 16 previously described. Valve 71 is sensitive to the temperature of the gas flowing through Venturi 74 which temperature is sensed by a probe which extends into the. Venturi.
Gas flows through the pump outlet 75 into the space between suit layers 50 and 51 and through the permeable layer 51 around the users body. .Advantageously it is conducted from the interior of the suit back to the gas passages of housing 55 in which the heat exchangers or evaporators 59 and 65 are disposed by a pair of ducts 81 and 82 arranged to fit over the shoulders of the suit wearer and extending from the front portion of the suit inside inner layer 52 to a connection in the upper part of housing 55 above the heat exchangers.
Referring to FIG. 1, the vessel 85, fill vent valve 86, pressure closing valve 87, warming and evaporating coil 88, filling line control valve 89 and inlet line 90 correspond in function to vessel 32, valves 39 and 38, coil 37, valve 35, and inlet line 30 of FIG. 3, respectively. The valves and coils are mounted on the vessel 85 which is removably held on the housing 55 by strips and brackets 91.
The trap 92 shown at the bottom of FIGS. 1 and 2 is like the trap 40 of FIG. 3 in operation and the operation of the system illustrated in FIGS. 1 and 2 is the same as the operation of the circuit of FIG. 3.
Operation of the valves may be manual or, as shown in the form of the valve numbered 70, it may be automatic. Automatic operation is preferred. In cases where high eificiency is not required, as for example in a fire fighters suit, valve switching may be accomplished as a function of time without regard to frost build-up at intervals sufficiently frequent to insure that a heavy frost will not be accumulated. On the other hand, in cases where the system is used for longer periods and high efliciency is required, as for example in a rocket fuel handlers suit, the valve is advantageously operated when the frost build-up has reached a selected amount.
It is considered preferable that valve operation be thermostatically controlled and valve 70 of FIGS. 1 and 2is so controlled as best illustrated in FIG. 4 wherein partitions in a valve body divide the body into two inlet chambers 101 and 102 and a common outlet chamber 103. Chambers 101 and 102 have inlets 104 and 105, respectively, and chamber 103 has an outlet 106. A pair of normally closed valves 107 and 108, having stems 109 and 110, connect chambers 101 and 102 with chamber 103. These stems extend through respectively associated seals into an actuating chamber 111.
A lever 112, which is pivotally mounted in chamber 111 and connected to an overcenter spring 113, is disposed so that its ends overlie a respectively associated one of aneroid bellows 114 and 115 which expand to move the lever, tripping it overcenter as the pressure changes and first one bellows and then the other expands sufficiently to trip the spring. The interior of bellows 114 is connected by a tube 116 to a sealed liquid-gas container 117 disposed where it will be sensitive to heat exchanger temperature. Similarly the interior of bellows 115 is connected by tube 118 to a sealed liquid-gas container 119. In the drawing, the contents of containers 117 and 119 is Freon, as shown.
1. A respiratory and atmosphere conditioning system for an enclosed space; comprising an inlet for pressurized, low temperature, respiratory fluid; a Venturi pump including a jet nozzle, an aspirating inlet and a pump outlet; a pair of heat exchangers, each connected between said inlet and said jet nozzle and including valve means for interrupting the connection through said heat exchangers alternately; means responsive to heat exchanger temperature values for actuating said valve means; and passage means for circulating gas from said enclosed space past both heat exchangers into said aspirating inlet and thence out said pump outlet and into said enclosed space.
2. The invention defined in claim 1 including means for collecting and separating from said enclosed space condensate formed on said heat exchangers.
3. The invention defined in claim 1 including means for controlling the rate of flow of gas through said jet nozzle.
4. A respiratory and atmosphere conditioning system for an enclosed space; comprising a Venturi pump including a jet nozzle, an aspirating inlet and a pump outlet; a liquid-to-respiratory gas converter system including a liquid source and a pair of heat exchangers connected between said source and said jet nozzle; means sensitive to the relative temperaturm in said heat exchangers for alternately interrupting the connection of one and then the other of said evaporators to said nozzle; passage means for circulating gas in the enclosed space past both heat exchangers into said aspirating inlet and out said pump outlet into said space.
5. The invention defined in claim 4 including a sump below said heat exchangers and a liquid trap connecting said sump to at least one of the surrounding atmosphere and a collection and storage vessel.
6. A respiratory and atmosphere conditioning system for an enclosed suit; comprising a Venturi pump including a jet nozzle, an aspirating inlet and a pump outlet;
an inlet for pressurized, low temperature respiratory ing the other end of said heat exchangers to said jet nozzle; and passage means for circulating gas from the suit past both heat exchangers into said aspirating inlet and thence through the pump outlet back into the suit including a pair of ducts arcuately formed to fit over the shoulders of a suit wearer.
7. The invention defined in claim 6 in which said heat exchangers are disposed below and in the path of gas flowing through said ducts, respectively, and said valve means and pump are disposed between said heat exchangers.
8. In combination, an enclosed suit having an outer impervious layer and an inner layer through which gas may pass; a housing carried at the rear of said suit; a pair of heat exchangers disposed in said housing; an inlet for pressurized, low temperature respiratory fluid connected to the lower end of each heat exchanger; a Venturi pump in said housing having a jet nozzle, an aspirating inlet and a pump outlet; means including valve means for connecting the upper ends of said heat exchangers to said jet nozzle alternately; and means for circulating gas from the suit past both heat exchangers into said aspirating inlet and thence out said pump outlet into the suit including, a pair of ducts formed to fit over a suit wearers shoulders and extending from the front portion of the suit inside said inner layer to a connection at the upper part of said housing, and a connection from said pump outlet to the space intermediate said suit layers.
9. The invention defined in claim 8 in which said suit is provided with a sight opening and a gas outlet arranged to direct gas toward said opening.
References Cited in the file of this patent UNITED STATES PATENTS 2,089,428 Ross Aug. 10, 1937 2,576,985 Wildhack Dec. 4, 1951 2,763,132 Jue Sept. 18, 1956 FOREIGN PATENTS 331,363 Germany Jan. 6, 1921 609,660 Germany Feb. 19, 193.5