US2517498A

US2517498A - Air conditioning system

Info

Publication number: US2517498A
Application number: US602002A
Authority: US
Inventors: Mcgrath William Loughney
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 1945-06-28
Filing date: 1945-06-28
Publication date: 1950-08-01
Anticipated expiration: 1967-08-01

Description

Aug., 1, 195o w L, MCGRATH 2,517,498

AIR CONDITI ONING SYSTEM Filed June 28, 1945 Patented Aug. l, 1950 AIB CONDITIONING SYSTEIK William Loughney McGrath, Syracuse, N. Y., al-

signor to Carrier Corporation, Syracuse, N. Y., a corporation of Delaware Application June 28, 1945, Serial N0. 602,002

voisins. l

mais invention relates to air conditioning systems and, more particularly, to systems in which air is tempered under dillerent operating conditions by the circulation of heated or cooled water or other fluid through one or more heat exchangers.

ln Carrier Patents Nos. 2,363,294 and 2,363,945, granted November 21, 1944 and November 28, 1944, respectively, there is disclosed an airconditioning system in which a volume of air is conditioned to a, desired degree at a central conditioning point, and is then distributed at `relatively high static pressure and at relatively high velocity to a plurality of units respectively disposed in and serving a plurality of areas or enclosures to be conditioned. The high pressure air supplied to each unit is discharged therein through nozzle formations or the like, and in this manner induces a relatively great circulation of air withdrawn from the area served by the unit. The primary or conditioned air and the secondary or induced air are then supplied to the area to be conditioned. The primary air may be conditioned at a central conditioning point; and more edective and economical operation is achieved by the delivery i heated or cooled water or other huid to the various units from a.

central station preferably to eilect sensible cooling or heating oi' air circulated 'through the units as required.

In such system, it is necessary to supply some form of control to produce and to maintain desired atmospheric conditions. Carrier Patent No. 2,342,328, granted February 22, 1944, discloses for this purpose a valve structure capable of reflecting changes in air conditions and compensating for variations in such conditions during all seasons of the year. The system so described has been highly successful in commercial operation.

The chief object of the present invention is to provide a simple and modified system of this general type. l

an object of the invention is to provide an air conditioning system embodying improved means of supphfing conditioning medium to a plurality of air conditioning units disposed in different sones.

A further object is to provide an improved control for an air conditioning unit capable of satisfactory perfomance under different seasonal op- @rating conditions.

A still further object is to provide an improved control for delivering cooled or heated conditioning medium, automatically as desired, to one or more air conditioning units under different seasonal operating conditions.

A still further object is to provide a watercirculating system operating under relatively low pressure to govern the flow of conditioning medium of certain character through a conti-oli under certain seasonal operating conditions and in which an imposed pressure may be used when medium of other character is employed to change the operation of the control under other .seasonal operating conditions.

This invention relates to an air conditioning system which includes a unit for conditioning air. a supply of conditioning medium. a passageway or duct for supplying conditioning medium from said supply to said unit, a. second passageway or duct into which conditioning medium passes from said unit, and control means in said nrst passageway responsive to the pressure of the conditioning medium for controlling the circulation of conditioning medium through the unit. Preferably, means are lprovided for imposing a predetermined pressure on the conditioning medium in the rst passageway so that a predetermined increase in pressure may be employed to modify the operation of the control means; under various seasonal operating conditions.

This invention further relates to an improved control valve for systems of the character described which comprises, in combination, a. housing, a change-over element disposed in the housing, means lor causing said element to assume one position when conditioning medium under a predetermined pressure is fed to the valve and a second position when conditioning medium. under a diiIerent predetermined pressure is fed to the valve, a member for opening and closing a passageway from which conditioning medium is discharged from the valve, and means operative responsive to changing conditions in an :area being air conditioned for causing said member to tend t0 change the amount of conditioning medium nowing from the valve. Referring to the drawing illustrating a preferred embodiment of the invention,

Figure 1 is a diagrammatic view illustrating the air conditioning system of the present; invention;

Figure 2 is a sectional view. on an enlarged scale, of the control mechanism included in the system shown in Figure 1; and

Figure 3 is a diagrammatic view illustrating a modication of the invention.

Referring to Figure l, there is shown a diagrammatically an air conditioning system including source of supply or receiver I for providing to the system a desired volume of conditloiilns medium, which may be heated or cooled water or other fluid. A pump I sends the conditioning medium to a plurality of air conditioning units 4 through line 5. One or more units 4 may .be disposed in different zones of a building such as a hotel or oiilce building, and usually a number of them are placed on different levels or iioors of the building, one or more units serving each room or area. In Figure 1 three iloors are illustrated on which units 4 are positioned. Control valves 6 are disposed at each unit 4 or in the branch lines 5' leading to each unit and serve to control the circulation of conditioning medium through the units. 'A return line I is provided into which conditioning medium passes from the various units 4 and by which such medium .preferably is returned to the source of supply or receiver 2.

A closed expansion tank 8 is disposed in the system to maintain a predetermined pressure upon the conditioning medium in line 5. The pressure imposed by tank 8 upon conditioning medium in line 5 may be varied by means of a compressor or pump 9 connected to a changeover line I8. A thermostat T controls the operation of compressor 8 and may be actuated by means of a thermal responsive element II disposed in or in contact with line 5 and, preferably, positioned on the down stream side of pump 3, illustrated.

In Figure 2, there is illustrated the preferred control valve 8 employed in the system. Valve 6 comprises a housing I2 enclosing double-seated valve poppets I3 and I4. An entrance port I5 is provided at one side of housing I2 and an exit port I8 is provided on the other side of the housing. Separate passageways I l and I8 may be provided through the valve between ports I5 and I8, cooling medium passing through passageway I8 and heating medium passing through passageway Il'. The course of cooling uid is indicated by a dash line while the course of heating fluid is indicated by a dot and dash line. Poppets I3 and I4 control the ilow of fluid through passageways I 'I and I8, as will hereinafter be described. Poppet I3 is actuated by the pressure of the conditioning medium being fed to the valve while poppet I4 is actuated by the temperature of the area or space being conditionedboth serving to control the ilow of fluid through passageways I1 and I 8 under different seasonal and load requirements.

Valve poppet I3 is attached to a bellows I9 and is actuated by expansion and contraction thereof. A spring 20 is provided in housing I2 adapted to apply a predetermined force or pressure to bellows I9. The pressure or force applied by spring 20 may be adjusted as desired by means of the adjusting screw ZI.

The force applied to bellows I9 by spring 28 depends upon the hydraulic pressure maintained in the system. For example. under winter operating conditions, the force applied by spring 20 to bellows I8 is greater than the hydraulic pressure of the conditioning medium so that poppet I3 moves downward seating at the bottom to seal passageway I8 and to open passageway I'I; under summer operating conditions the pressure applied to the conditioning medium is greater than the force applied by spring 28 so that poppet I3 moves upward seating at the top to seal passageway I I and to open passageway 28.

Valve poppet I4 operates similarly to poppet I3 but in response to the temperature of the area being conditioned. A thermostat (not shown) is disposed in the area being conditioned and is connected to bellows 22 by line 23. A suitable limit regulating control (not shown) is also connected to bellows 22 by line 24. Fluid is disposed in the closed circuit connecting bellows 22, the thermostat and the limit regulating control. As the temperature in the area being conditioned rises, the iluid expands, expanding 'bellows 22 while upon a decrease in such temperature, the iiuid contracts, permitting bellows 22 .to contract. Such devices are well-known in the art and form no part of my invention per se. Spring 25 provides a resistance downwardly against poppet I4 opposed to the upward expansive force of bellows 22.

Considering the operation of the system under winter conditions, springs 20 of valves 8 disposed on different floors or building levels will be adjusted for diiferent hydraulic pressures in line 5. For example, referring to the system shown in Figure 1, spring 20 of the upper valve 8 (on the top oor) may be adjusted to resist a hydraulic pressure of conditioning medium of 15 pounds per square inch; spring 20 of the intermediate valve 8 may be adjusted to resist a pressure of conditioning medium of 25 pounds per square inch and spring 28 of the lower valve 6 (on the 'bottom oor) may be adjusted to resist a pressure of conditioning medium of 35 pounds per square inch. Thus, assuming the pressure of the conditioning medium is less than the amounts given at the various iioors, poppets I4 will be moved downwardly by 'springs 20 and open passageways I1 through the respective valves for the passage therethrough of heated conditioning medium.

Depending upon the temperature of the area being conditioned, poppet I4 will open or close passageway I 'I to the heated conditioning medium. Assuming the thermal responsive element disposed in the area being conditioned reilects a cool condition therein, the fluid in bellows 22 will be contracted, permitting spring 25 to move poppet I4 downward opening passageway I'I to the heated conditioning medium and permitting its ilow to the conditioning coils of the various units 4. As the temperature in the area being conditioned rises, bellows 22 will expand. moving poppet I4 upward against the resistance of spring 25 and partially or completely closing passageway I1.

Under summer operating conditions, an increase in static pressure of predetermined amount is imposed on conditioning medium in line 5 by means of compressor 9 and expansion tank 8. Such increase in pressure must be sufiicient to force the poppets I3 upward against the resistance of springs 20 thus closing passageways I I and opening passageways I 8. Increase of pressure is controlled by thermostat T operating pressure control P (shown in dotted outline) which actuates compressor 9. Thermostat T is actuated by thermal responsive element I I which reflects the temperature of conditioning medium in circuit 5. If the temperature of conditioning medium in line 5 is below a predetermined point, the compressor is actuated to impose increased pressure therein, say 10 pounds greater than under winter operating conditions.

Under summer operating conditions poppet I4 may be actuated to open or to close passageway I8. If the temperature in the area being conditioned reflects a warm condition, poppet I4 is forced upward by bellows 22 opening passageway I8. As the temperature in the area being conditioned decreases, bellows 22 contracts, permitting spring 25 to move poppet i4 downward thus closing or partially closing passageway I8. As described above, poppets I3 and I4 are` automatic in operation, poppet I3 being operable in response to the pressure of conditioning medium in the system and poppet I4 being operable in response to the temperature of the area being conditioned.

In Figure 3, I have illustrated a modified system generally similar to the system shown in Figure 1. In the system partially shown in Figure 3, an open expansion tanl: 26 is employed and compressor 9 may be eliminated. The tank 26 is connected to change-over line lil and the pressure imposed upon the conditioning medium in line 5 is determined by the level of conditioning medium maintained in tank 26. A float valve 21 maintains a certain level when under summer operating conditions to impose require-i pressure on conditioning medium while float valve 28 maintains a certain level under winter operating conditions, also imposing a predetermined pressure on the conditioning medium different than that imposed under summer operating conditions.

While I have described the system as requiring an increase in hydraulic pressure under summer conditions, it will be appreciated that a decrease in hydraulic pressure may be employed under such conditions; in such case, the valve 6 may be modified accordingly with the position of the temperature responsive element being reversed in order that the heated or cooled conditioning medium may ilow in different paths. Such modication is contemplated by my invention and may be made without departing from the scope thereof.

My invention provides an improved air conditioning system in which a change-over from winter to summer operating conditions is controlled by the hydraulic pressure of the conditioning medium which flows through the conditioning units of the system. The conditioning system is less complicated than systems heretofore used and is at least as economical in installation and operation costs. The unit controls provided are simple and actuatable by the pressure of the conditioning medium. The system operates satisactorily under both Winter and summerconditions and may be modified if desired to provide either heating or cooling in any season of the year to various zones with the result that any desired tempering may take place at any point of distribution.

While I have described a preferred embodiment of my invention. it will be understood my invention is not limited thereto since it may otherwise be embodied within the scope of the following claims.

I claim:

l. In a system of the character described. the combination of a plurality of units for conditioning air, a supply of conditioning medium, a passageway for supplying conditioning medium from said supply to said units, means for imposing a predetermined pressure on the conditioning medium in said passageway, and a plurality of valves in said passageway for controlling the circulation of conditioning medium through said units, at least one of said valves including a change-over element responsive to pressure of conditioning medium entering the valve, Ireans for changing the pressure imposed on the conditioning medium in said passageway, means for causing said element to assume. a first position said element being adapted to assrme a second position in response to a predetermined change in the pressure of the conditioning medium, a device for opening and closing a passageway from which conditioning medium is discharged from the valve, and means for operating said devicein response to changing conditions in an area being air conditioned.

2. A system according to claim 1, in which said device tends to reduce the flow of conditioning medium from the valve when said element is in the first position and the temperature in the area being conditioned tends to rise above a desired level and is adapted to tend to increasethe ilow of iluid from the Valve when said element is in the second position and the temperature in such area tends to rise above a desired level.

3. In a system of the character described, the combination of a plurality of units for conditioning air, a supply of conditioning medium, a passageway for supplying conditioning medium from said supply to said units, a second passageway for returning conditioning medium to said supply after it has passed through said units, an expansion tank connected to said first passageway for imposing a predetermined pressure on conditioning medium therein, means for imposing a predetermined pressure on conditioning medium in said tank, a valve at each unit for admitting conditioning medium to the unit, means in each valve for closing a `port therein under a predetermined pressure of conditioning medium and opening said port under an increase in said predetermined pressure of the conditioning medium, and means in each valve responsive to the temperature of the area being conditioned for metering the volume of fluid passing through the valve.

4. A system according to claim 3 in which an open expansion tank is employed, the pressure imposed upon the conditioning medium being predetermined by float valves in said tank for maintaining a desired level of conditioning medium therein.

5. In a system of the character described, the combination of a plurality of units for conditioning air, a supply of conditioning medium, a passageway for supplying conditioning medium from said supply to said units, a second passageway for returning conditioning medium to said supply after it has passed through said units, an expansion tank connected to said flrst passageway for imposing a predetermined pressure on conditioning medium therein, means for imposing a predetermined pressure on conditioning medium in said tank and a valve at each unit for admitting conditioning medium to the unit, said valve comprising a change-over element responsive to pressure of conditioning medium entering the valve, means for causing said element to assume a iirst position, said element being adapted to assume a second position in response to a predetermined change in the pressure of the conditioning medium, a device for opening and closing a passageway from which conditioning medium is discharged from the valve, and means for operating said device in response to changing conditions in an area being air conditioned.

6. In a system of the character described, the combination of Va plurality of units for conditioning air, a supply of conditioning medium, a passageway for supplying conditioning medium from said supply to said units, a second passageway for returning conditioning medium to said supply after it has passed through said units, an expansion tank connected to said rst passageway for imposing a predetermined pressure on conditioning medium therein, means for imposingr a predetermined pressure on conditioning medium in said tank, and a conditioning medium ow :mimos regulating device at each unit for regulating the circulation of conditioning medium through the units, said device comprising a. iirst valve. means for retaining said valve in a iirst position, said valve being movable to a second position in response to an increase in pressure of conditioning medium owing through the valve, a secondvalve, and means responsive to changing conditions in an area being air conditioned for changing the position of said second valve to meter the amount of conditioning medium flowing through the valve.

7. In a system of the character described, the combination of a plurality of units for conditioning air, a supply of conditioning medium, a passageway for supplying conditioning medium from said supply to said units, a second passageway for returning conditioning medium to said supply after it has passed through said units, an expansion tank connected to said rst passageway for imposing a predetermined pressure on conditioning medium therein, means for imposing a predetermined pressure on conditioning medium in said tank, and a control valve at each unit for regulating the circulation of conditioning medium through the units, said valve including a first upper passage, a first lower passage, a second upper passage, a second lower passage, means 8 i for admitting a first conditioning medium to the valve, means operative responsive to the pressure of said conditioning medium for causing one o! said ilrst passages to be open and the other to be closed, second means for causing one of said second passages to be open and the other second passage to be closed, and a temperature responsive element for actuating said second means in response to changing temperature conditions in an area being air conditioned.

WILLIAM LOUGHNEY MCGRATH.

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

UNITED STATES PATENTS Number Name Date Re. 22,685 Carrier Oct. 30. 1945 1,769,859 Roberts July 1, 1930 1,979,779 Tobin Nov. 6, 1934 1,990,663 Muiily Feb. 12, i935 2,238,689 Locke Apr. 15, 1941 2,292,335 Durbin Aug. 4, 1942 2,299,404 Newton Oct. 20, 1942 2,353,889 Giesler July 18, 1944 2,372,839 McGrath Apr. 3, 1945