US2044538A

US2044538A - Air conditioning apparatus

Info

Publication number: US2044538A
Application number: US14725A
Authority: US
Inventors: Maxwell F May
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-04-04
Filing date: 1935-04-04
Publication date: 1936-06-16
Anticipated expiration: 1953-06-16

Description

June 116 1936.

M. F. MAY 2,044,538

AIR CONDITIONING APPARATUS 2 Sheets-Sheet 1 Filed April 4, 1935 7? 7? axzae m,

June 16, 1936. M. F. MAY 2,044,538

AIR CONDITIONING APPARATUS Filed April 4, 1955 2 SheetsSheet 2 lily. 6?,

Patented June 16, 1936 UNITED STATES PATENT OFFICE AIR CONDITIONING APPARATUS Maxwell F. May, Palos Park, 111.

Application April 4, 1935, Serial No. 14,725

15 Claims.

This invention relates to air conditioning apparatus, and more particularly to such apparatus wherein at least two speeds of air circulation are provided.

One feature of this invention is that it provides a gentle current of tempered air; another feature of this invention is that it provides, when required, a stronger current of heated air; still another feature of this invention is that it either cools or heats the air, as the outside temperature requires; yet another feature of this invention is that it is completely automatic in operation; other features and advantages of this invention will become apparent from the following specification and the drawings, in which- Figure l is a side elevation, partly in section, of an installation embodying my invention; and Fig. 2 is a schematic diagram of the electrical control circuit.

Conventional air conditioning systems are so constructed as to provide a given volume of air at a given temperature to the room which it is desired to heat or cool and control of the temperature level in the room is achieved through starting and stopping this flow of air. This is true both of hot air systems used for heating and air conditioning systems used for cooling. This method is open to several objections. One ob jection is that in the period during which the system is inoperative the air in the room tends to stratify. When the air current again starts to flow, moreover, there is a distinct and unpleasant sense of immediate temperature change, resulting from the entrance of a strong current of air at a considerable temperature gradient with respect to the room air into the stratified and quiet air of the room.

This invention obviates these objections by providing, when the outdoor temperature requires it, a gentle current of tempered air continuously flowing into the room. At outdoor temperatures below 55, for example, a gentle current of air having a small temperature gradient with respect to the air in the room, for example 20 or 25 higher, would flow continuously. This current of tempered air would avoid Stratification of the air in the room and would provide a certain amount of heat, at such low air speed and low temperature gradient as to be entirely unnoticeable to any occupants of the room. When the temperature in the room, however, finally drops below the desired setting, the system is stepped up to furnish a much larger volume of heated air, as for example air at 145 or 150. While this stronger current is noticeable, there is no unpleasant feeling of sudden temperature change. since there has been a continuous gentle current of slightly warmed air coming into the room.

In the particular embodiment of this invention illustrated herewith, a building I is shown hav- 5 ing outer walls II and I2, rooms l3 and I4, and a basement 15. The wall or partition I6 between the rooms I3'and I4 is shown provided with an air duct ll, which ductopens into the rooms, as at l8 and I9. Suitable air return means are provid- 10 ed, as for example the

conduits

20 and 2|. The duct ll is-considerably enlarged in the basement, and contains therein heat transfer means or coils, as the coils A, B and C. A blower or fan 22 is provided to force air through the duct, which fan is driven by an electric motor D, here shown as a 2-speed motor. The duct ll would in a commercial installation, be provided with humidifying and dehumidifying devices to regulate the moisture content of the air being supplied to the rooms. Such devices are not illustrated here, however, since they form no part of the present invention. A boiler 23 furnishes hot water and steam to the coils, and is provided with automatic firing means, here shown as the stoker 25 24 driven by the motor 25. The boiler is provided with an aquastat 26, normally set to keep the boiler water temperature at approximately 170, and with a steam pressure switch 21.

When the system is set for heating, valves 29 30 and 30 are manually closed, valve 3| is opened wide, and throttle valve 32 is partly opened. A gravity circulation is thus provided for the hot water in the boiler out through the tempering coil C, down through the valve 3| and back 35 through the return pipe 33 to the boiler. The amount or rate of water flow through this gravity system may be regulated by adjustment of the throttle valve 32. This gravity system is also provided with an automatically operated valve, here shown as a solenoid operated valve 34, which valve is normally closed, but is opened wide upon an urgent demand for heat by the room thermostat 35 located for example in the temperature responsive means or thermostat box 35. The

valves

32 and 34 are actually at the same vertical level, but are here shown in perspective. A steam pipe 3'! serves to energize the heating coil A, that is, to furnish it with steam when steam pressure is up in the boiler, a return line being provided by the steam pipe 38 and the return pipe 33.

In the summer, when the system will be used only for cooling, valves v39, 29 and 30 are opened, and valves 3|, 32 and 34 are closed. Cold water, or other cooling medium, is forced through the the boiler.

pipe 40, the coils B and C, and out the pipe 4|. The pipe 40 is provided with an automatically operated valve 42. This valve, in combination with one of the cooling thermostats 43, serves to regulate the flow of cooling medium through the coils B and C, in accordance with the temperature conditions of the room. It will be noted that even when the system is thus set for cooling a sudden drop in outdoor temperature would cause the thermostat 28 to shift the electrical control system over to heating and the air being forced through the duct would be heated by the steam coil A as soon as steam pressure was raised in Thus the system is able to automatically react to unexpected changes in outdoor temperature, even though it would not provide the desirable gentle current of tempered air when the various manually operated valves are set in the positions last described.

Referring more particularly to Fig. 2, it will be noted that the outdoor thermostat 28 controls a 2-pole 2-throw relay 44. The poles'of this relay are supplied with current to energize the control system, as by commercial 110-volt AC lines 45 and 45. In the construction illustrated here, the thermostat. is arranged so as to remain open while the temperature is below 75,

and to close when the outdoortemperature is above that point.

When the thermostat 28 is open the relay makes connections between lines 45 and 4B and the lines 41 and 48, which lines supply the heating control system with energy. When the outdoor temperature rises above the predetermined value of 75, the thermostat 2B closes, thus closing the relay 44, and causing the lines 45 and 45 to energize the lines 49 and 50, which lines supply current to the cooling system.

Assuming the outdoor temperature to be such that the heating system is energized, the room thermostats 35 and 5| will be energized through their respective transformers. These thermostats are preferably set about 1 apart, for example, thermostat 35 being set at 71 and thermostat 5| at 72. Whenever the room temperature is below 72 the temperature responsive device or room thermostat 5| will close, thus energizing the 2-pole single throw relay 52, which closes the circuit to the fan

motor supply lines

53 and 54. This circuit is completed through either of two switches in parallel, which switches are here shown as an aquastat 55 located in the coil C, or in the pipe leading thereto, and the limit switch 56, which switch is located in the air duct. Should both the air in the duct and the water in the tempering coil C be cold, the circuit will thus remain open to the fan motor, in order to prevent cold air from being forced into the room. As long as there is hot water in the coil C, however, or the air in the duct is warm, the circuit will be completed and the fan will operate.

The fan motor D is here shown as a 2-speed motor, controlled by the 2-pole 2-throw relay 57. This relay, when not energized, connects the

motor feed lines

53 and 54 with the low speed connections 58 and 59. Two switches or controls are provided in connection with the relay 51, the steam pressure switch 21 and the thermostat 60. The steam pressure switch 21 is located in the boiler and closes whenever the steam pressure, as a result of firing of the boiler, is high enough to energize the heating coil A. The thermostat 60 is located outside the building, preferably adjacent the thermostat 28, and serves to energize the relay at outdoor temperatures above approximately It may thus be seen that when the heating control system is operative the fan motor is stepped up to high speed by the closing of the switch 21 as soon as there is suflicient steam in the coils A to heat the coils to the desired tem- 5 perature. When the system is set for cooling, on the other hand, outdoor temperatures above 90 cause the fan to operate at high speed, thus adjusting the capacity of the cooling system to the outdoor temperature. 10

The stoker motor 25 is supplied with current either through the lines 6| and 62, or through the

lines

53 and 64. Current through the lines 6| and 62 is controlled by the aquastat 26, and is dependent upon boiler water temperature. As 15 normally set, the aquastat serves to keep the water in the boiler always above 170. The

lines

63 and 64 have their circuit completed to the main supply lines 45 and 46 through the doublepole single-throw relay 65. This relay is con- 20 trolled by the room thermostat 35. The relay 65 also has in combination therewith a single-pole double-throw switch which serves to energize the electrically operated valve 34 in the supply line to the tempering coil C. When the relay 55 25 is energized, upon a more urgent demand for heat by the room thermostat 35, the circuit to the stoker motor 25 is completed and the valve 34 is electrically opened wide. This valve may be solenoid operated, as is valve 42 in the cooling 30 line. Energy to operate both of these automatic valves, 42 and '34, is supplied by lines 65 and 61 from the secondary of a step down transformer 68. Current to operate each of the various relays illustrated is, in the usual commercial form, 35 supplied by a separate transformer built integrally with the relay.

Assuming the outdoor temperature to be about 60, the thermostat 28 would be open and the control system for heating would be energized 40 through the lower contacts of the relay 44. Whenever the room temperature drops below 72, the closing of the thermostat 5| energizes the low speed connections to the fan motor. A gentle current of air is thus driven upwards through the 5 duct, passing through or over the tempering coil C. The manual throttle .valve 32 is preferably permanently adiustedat a point which will permit just sufficient gravity flow of hotwater through the coil C to raise the temperature of the 50 air to the duct, at low fan speed, to about This gentle current of air warms the room until thetemperature has risen above 72, whereupon the thermostat 5| opens and the system ceases to operate. Should the outdoor temperature be much lower, however, as for example 30, the heat losses from the building would be slightly greater than the heat that could be supplied by the system operating with the fan at low speed and the tempering coil only. There will thus 60 be, a constant current of temperate air flowing into the room, since it will never be able to raise the temperature above,72. Whenever the room temperature drops below 71, however, the thermostat 35 will close, thus energizing the o5 stoker motor-and opening the automatic valve 34 wide. There will thus be a greater flow of hot water through the coil C, and a consequent slight rise in temperature of the air being supplied to the room. As soon as the steam pressure 7 in the boiler has risen to a point sufficient to properly energize the heating coil A, the steam pressure switch 21 closes, thus energizing the relay 5'! and raising the fan to high speed operation. A strong current of heated air will thus be sup- 75 aosasss a plied to the room until such time as the temperature at the thermostat box 36 rises above 71, at which timethe thermostat 35 will open, thus closing the valve 34 and rendering the stoker motor inoperative. The fan will continue to operate at high speed, however, until the steam pressure has dropped sumciently to allow the steam pressure switch 2'! to open, whereupon the fan will drop to low speed and again supply the continuous current of tempered air.

When the outdoor temperature is above the point for which the thermostat 28 is set it will close, energizing the relay it and switching the system over to cooling, assuming that the

manual valves

39, 29 and 30 are open. These valves are manually operable, rather than automatic, since they would only have to be set in the spring and fall. Two cooling thermostats are provided in the room, 43 and These thermostats are preferably set about 3 apart, for example thermostat 69 may be set to close at 76 and thermostat 33 set to close the contact 10 at 79. The thermostat 69 controls the relay 71, which is similar to relay 65, while the thermostat 13 controls the automatic valve 62, opening the valve above tem-' peratures of 79 and closing it below that temperature. The valve t2 controls the flow of cooling medium through the cooling coils. As long as the outdoor temperature is below 90, thus leaving the thermostat 60 open, and the room temperature is above 76, thus keeping the thermostat 69 closed, the fan motor will operate at low speed to force a gentle current of air through the ducts and thus give an effective cooling action without the flow of any cooling medium through the coils B and C. As soon as the room temperature rises above 79, however, valve 32 will be opened by the action of thermostat (i3, and the cooling medium will flow through the cooling coils in the duct. The fan will continue to operate at low speed, and the cooled air will flow through the ducts into the room until the room temperature drops below 79, whereupon the valve 32 will be closed by the thermostat 53. Outdoor temperatures above 90 close the thermostat. 60 and thus cause the fan motor to operate at a high speed, insuring suihcient cooling capacity in the system at high outdoor tempera tures.

It will be noted that, in the steam boiler system heretofore illustrated and described, the tempering coil C is supplied with hot water from the boiler 23 by gravity flow, although the coil A is energized by steam when steam is raised in the boiler. Should it be desired to have the entire system hot water operated, the heating coil A would be energized by hot water circulated through it by a force pump. The tempering coil C, however, would still be supplied by gravity flow. The gravity flow feed of the tempering coil is an advantage, since in cold weather this coil oper ates continuously. Were the tempering coil to be energized by forced feed of hot water, for example, the circulating pump would have to operate continuously in cold weather.

While I have shown and described certain sinbodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed inthe appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as permissible, in view of the prior art.

rendering said fan operative at a low speed upon a demand from said demand means; means rendering said main heat transfer means opera tive upon a more urgent demand from said demand means; and means rendering said fan erative at a high speed when said main heat transfer means is operative.

2. Apparatus of the character described, in eluding: an air duct adapted to supply air to a room; means in said duct for heating. said air; means in said duct for continuously tempering said air; temperature responsive demand means in said room; means for forcing a gentle current of air through said duct upon a demand from said temperature responsive means; and means -for rendering said heating means operative and for forcing a strong current of air through said duct upon a more urgent demand from said temperature responsive means.

3. Apparatus of the character described, ineluding: an air ductadapted to supply air to a room; a steam coil for heating said air; a hot water coil for tempering said air; temperature responsive demand means in said room; a fan adapted to force said air through said duct, said fan having at least two speeds; means rendering said fan operative at a low speed upon a demand from said temperature responsive means, whereby a gentle current of tempered air is forced through said duct to said room; means for energizing said steam coii upon a more ingent demand from said temperature responsive means; and means for rendering said fan operative at a high speed when said steam coil is energized.

l. Apparatus of the character described, th eluding: an air duct adapted to supply air to a room; a steam coil for heating said air; hot water coil for tempering said air; "temperature responsive demand means in said room; a second temperature responsive demand means in said room; a fan adapted to force said air through said duct, said fan having at least two speeds; a boiler continuously supplying said hot water coil with water; means for rendering said fan operative at a low speed upon a demand from said first mentioned temperature responsive means, whereby a gentle current of tempered air is forced. through said duct to said room; means for generating steam to energize said steam coil upon a demand from said second mentioned tempera ture responsive means; and means for rendering said fan operative at a high speed when said steam coil is energized.

5. Apparatus of the character claimed in claim 4., wherein said second mentioned temperature responsive means is responsive to a temperature about 1 lower than that for which said first mentioned temperature responsive means is set.

6. Apparatus of the character described, ineluding: an air duct adapted to supply air to a room; means in said duct for cooling said air; temperature responsive demand means in said room; means for forcing a gentle current of air through said duct upon a demand from said temperature responsive means; and means for rendering said cooling means operative upon a more urgent demand from said temperature responsive means, whereby a current of cooled air is forced through said duct. I

7. Apparatus of the character described, including: an air duct adapted to supply air to a room; means in said duct for cooling said air; temperature responsive means in said room; means for forcing a current of air through said duct upon a demand from said temperature responsive means, said means including a fan having at least two speeds; temperature responsive demand means exposed to the outdoor temperature; and means whereby said last named temperature responsive means causes said fan to operate at a -high speed when said outdoor temperature is above a predetermined point.

8. Apparatus of the character claimed in claim 1, wherein the auxiliary heat transfer means is continuously fed by a gravity flow of hot water.

9. Apparatus of the character claimed in claim 2, wherein the tempering means comprises a coil continuously fed by a gravity flow of hot water.

10. Apparatus of the character claimed in claim 3, wherein the hot water coil is continuously fed by gravity flow.

11. Apparatus of the character claimed in claim 4, wherein the hot water coil is supplied with water from said boiler by gravity flow.

12. Apparatus of the character described, including: an air duct. adapted to supply air to a room; a boiler; main heat transfer means, in said duct, connected thereto; auxiliary heat transfer means, in said duct, connected thereto, said means being energized by hot water from said boiler; temperature responsive demand means; and means, responsive to a demand from said temperature responsive means, forv raising steam in said boiler, whereby said main heat transfer means is energized.

13. Apparatus of the character described, including: an air duct adapted to supply air to a room; temperature responsive demand means in said room; a steam coil for heating said air; a hot water coil for tempering said air; a boiler supplying said hot water coil continuously with hot water; means, responsive to a demand from said temperature responsive means, for forcing a current of tempered air through said duct to said room; and means, responsive to a more urgent demand from said temperature responsive means, for raising steam to energize said steam coil, whereby a current of heated air is forced through said duct.

14. Apparatus of the character claimed in claim 13, wherein said hot water coil is supplied continuously with hot water from said boiler by gravity flow.

15. Apparatus of the character described, including: an air duct adapted to supply air to a room; temperature responsive demand means in said room; main heat transfer means for heating said air; a hot water coil for tempering said air; a boiler supplying said hot water coil continuously with hot water; means, responsive to a demand from said temperature responsive means, for forcing a current of tempered air through said duct to said room; and means, responsive to a more urgent demand from said temperature responsive means, for energizing said main heat transfer means, whereby a current of heated air is forced through said duct.

wMAXWELL F. MAY.