US2387576A

US2387576A - Heating system

Info

Publication number: US2387576A
Application number: US473720A
Authority: US
Inventors: Charles W Graves
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-01-27
Filing date: 1943-01-27
Publication date: 1945-10-23
Anticipated expiration: 1962-10-23

Description

Oct. 23, 1945. c. w. GRAVES HEATING SYSTEM Filed Jan. 27, 1943 F M n P V t W 1 11f q 1 4 /a /9 N m T 2 1J g I I N VEN TOR.

CHARLES \MBRAvEs,

Patented Oct. 23, 1945 UNITED STATES PATENT OFFICE 2,387,576 HEATING SYSTEM Charles W. Graves, Arlington, Mass. Application January 27, 1943, Serial No. 473,720 g p c ZClaims. (Cl. 237-9) IThis invention relates to steam heating systems of that class wherein heat is supplied periodically, or in cycles, to the radiators thereof under control of a room thermostat, mechanically operated dampers or the like.

In systems of the class referred to ithas heretofore been common practice to equip each radiator with a thermostatic air vent valve of that type which permits the escape of relatively cool or cold air from the radiators as steam pressure is built up within the same, but which closes automatically when heated by the steam that is delivered-to the radiators.

It is also true of such systems that during periods of idleness of the steam generator the temperature and pressure of the steam within each radiator would at times fall suiilclently low to cause the radiator air vent valve to open and admit relatively cold air to the radiator to recharge the system with air at atmospheric pressure before the commencement of the next heating cycle. This admission of cold air to the radiator at such times was objectionable, mainly for the reason that it reduced the temperature of the radiator and its contents at the expense of heat units.

My invention has for its principal object to obviate the objectionable feature just referred to and to provide an improved heating system of the class described so constructed and organized that when, during operation of the system, the pressure therein falls to slightly below atmospheric pressure during a period of rest of the steam generator, then pre-heated air at atmos pheric pressure will be delivered automatically" into the system as required to maintain the pressure therein approximately at atmospheric pressure so that no air is taken into' the system through the radiator vent valves, said delivery of pre-heated air being effected independently of the room thermostat or other heater-controlling means.

Other features of the invention are hereinafter pointed out.

In the accompanying drawing:

Figure 1 is a view, more or less diagrammatic, showing a heating system constructed and operating in accordance with this invention.

Figure 2 is an elevation, partly in section, of one of the air vent valves hereinafter referred to. V

Figure 3 is an elevation, partly in section, of one of the radiator vacuum air vent valves hereinatter referred to.

Figure 4 is a section on line 4-4-0! Fig. 1. I

The steam heating system illustrated :in"Fig,Z1 of the drawingcomprises a steam generator l0 provided at its base with a. burner ll equipped with .a control box. I! connected by a circuit l3 with a room thermostat I4 located withinone of the spaces or'rooms to \be heated. When circuit I3 is closed by thei'mostat H the .burner H is in operation and when opened atthe thermostat the burner is out of operation.

Generator I0 is made with a boiler l5 within which water is maintained at a predetermined level so as to provide a steam space It zatxthe top thereof. This steam space is connectedby risers ll withfthe radiators l8 located within the spaces or rooms to be heated, the thermostat l4 being arrangedwithin one of the latter. Adjacent to its radiator each riser I1 is provided, as usual, with a shut-off valve I9 which is open while the radiator is in use.

Each radiator i8 is equipped with a vacuum air outlet valve 20 (Figs. 1 and 3) which is preferably of a well known type that is inycommon use at the present time. A valve of the kind referred to is also illustrated in Fig. 3 of U. s. patent to Ferguson, et al., No. 2,06 2,565 dated December 1, 1936. v a e This type of valve comprises a base a to which is secured a casing 22 by means of a coupling ring 0. An eilteriorly threaded nipple d provided on base a is screwed into a tapped hole provided in its radiator and loosely confined within said nipple is one end of a syphon tube e which returns condensate to the radiator. At the top of casing b is provided an outlet port ,1 formed with a valve seat 'at its inner end. Adjustably mounted within the base a, and extending below the same, is a tubular stem g which supports ajpressure-operated bellows h disposed within casing b. This bellows abuts and supports a thermostatic float 7' provided at its top with a valve stem k co-operating with the inner seat end of outlet port I. The inner end of tubular stem 9 communicates with .the interior of bellows .h while its outer end communicates with the outside atmosphere.

The float j is supported by stem g and bellows h and usually has a small quantity of 'vola tile liquid contained within. Thus when the float is cold thebottom thereof is concaved but when its temperature is raised by thepresence of steam within the valve said bottom is caused to assume a convexshape due. to the expansion of thefluid within the float and this elongation of the latter closes the valve k.

Because otthe fact that atmospheric pressure always exists within the bellows h the latter will be maintained in its normal unexpanded condition so long as the pressure within casing b is at or above atmospheric pressure, but when, during operation of the system, the pressure within said casing falls below atmospheric pressure then the bellows tends to expand and will act through float 9' to maintain valve k in its closed position. In other Words the radiator valve 20 is Open when the system is first started thereby to permit air to vent from the system as the pressure and temperature within the latter builds up and when this takes place heat is transmitted from theradiator to the thermostatic element 7'. Fig. 3, which then operates to close valve 1c. Thereafter, during the operation of th system the valve 2|] remains closed and no air is permitted to enter at said valve when a vacuum develops within the system for reasons that-will appear later.

Thus, valve 20 is open only while the system is being started up and then only until the steam reaches and heats its thermostatic float whereupon valve 2|) is automatically closed by expan- 'sion of the float. Thereafter, so long as the system is in operation and regardless of pressure variation therein, the valve 20 will remain closed as will be made clear later. I

' The top of the boiler I5 is made with a threaded aperture into which is tightly screwed the lower exteriorly threaded end of an upwardly extending metal pipe 2| Whose upper end is'closed by a cap 22. This pipe 2|, in the illustrated example, is a one-inch iron pipe about six feet long and it is maintained heated, particularly the lower end portion thereof, to a substantial degree by heat transmitted to it from the top of the boiler l5, so that it serves as presently to be described not only as an air reservoir but also as an air heating retort.

At about eighteen inches above the top of generator ID the pipe retort 2| is provided with a plurality of inwardly-opening thermostatic air inlet valve units 23 (Figs. 1, 2 and 4) which may each be constructed as shown in Fig. 2.

' Each air inlet valve .unit 23. comprises a base a into the top of which is telescopically fitted and secured the lower end of a sheet metal casing b. At one side thereof the base a is made with an exteriorly threaded nipple d screwed into a tapped hole provided in pipe 2|. Nipple d is tubular and its inner end communicates with the interiors of base a and easing b. Within this nipple is loosely confined one end of a small syphon tube e for returning condensate ,topipe2l.

the seat at the inner end of port f. Air valves 23 of the type shown in Fig. 2 of the drawing are old and well known.

Since the capacity of the inlet port I of each valve 23 is small I have found it convenient and desirable, when using the standard make, to em ploy a plurality of these valves as shown in Figs. 1 and 4, in order to afford ample inlet capacity.

During each period of idleness of burner and cools the valves 23 which thereupon open and the temperature and pressure of the steam within the system, including pipe 2|, teadily decreases and if and when the pressure passes slightly below the outside atmospheric pressure, then the accompanying proportionate reduction in the temperature of the top of boiler l5, pipe 2| and the valves 23, causes the latter to open and admit air to the lower hot vertical section of pipe 2| by which it is heated as it passes through the same into the steam space of boiler l5.

Thi breaks the vacuum and immediately restores the pressure within the boiler to atmospheric, the pointer 3| of a steam pressure gauge 30 being returned from a negative position to its neutral position at zero on the gauge dial. Continued idleness of burner results in the pressurewithin the system again falling to slightly belowatmospheric and this is accompanied by the automatic-delivery of more pre-heated air into the boiler through valves 23 and pipe 2|, thereby again restoring pointer 3| to zero posi tion from a negative pressure-indicating position into which it is moved each time the pressure falls slightly below atmospheric.

Valves 23 are normally closed and remain so until the pressure within the boiler falls below atmospheric whereupon the relatively cool air in the upper part of pipe 2| expands downwardly admit air to the boiler which destroys the vacuum. The air thus admitted is preheated as it passes through the lower hottest portion of the pipe 2 I.

In this way pre-heated air will be intermittently delivered into boiler l5, and pointer 3| will continue to be slightly vibrated between zero p sition and a negative pressure-indicating position, so long as the burner remains idle.

During these air replenishing operations no cold air will enter the radiators l8 through the valves 20 for the reason that the latter are retained in their closed condition automatically by their bellows h each time the pressure falls below atmospheric.

When the burner H is again started by the room thermostat and the temperature of pipe 2| and vent valves 23 i raised, the latter are again closed and maintained so through expansion of their floats 7". This condition continues to exist until the burner is again stopped and the pressure within the system again falls to slightly be low atmospheric or zero, whereupon the above described air replenishing action is repeated.

From the above description it will be observed that the radiator valves 20 are thermostatically closed when the system isfirst started up and that they are, maintained closed during the air replenishing period. Also that the valves 23 are primarily temperature-controlled although their opening movements are assisted by outside air pressure when the pressure within the system falls to just below atmospheric.

The heated pipe 2| serves as a reservoir holding a volume of heated air some of which moves into the boiler I5 owing to expansion thereof as the pressure within the system declines during the first part of each period of rest of the burner and before the valves '23 open, while the hottest portion of pipe 2| that is between the vent valves 22 and the boiler serves as a retort-conduit to pro-heat the air' that is admitted through said valves 33 after said valves open.

wer

The cost of operating the above described system is greatly reduced from that entailed m op erating the system with the pipe retort 2| eliminated. One system operated by me and constructed as above described showed an operating cost of one and nine-tenths cents per hour while the same system without the pipe retort and constructed as heretofore showed an operating cost of three and one-half cents per hour.

While I have herein shown a room thermostat II as automatically controlling the generation of steam by boiler l so as to supply heat periodically to the radiators, it is to be understood that any other suitable means such, for example, as mechanically operated dampers, may be employed in lieu thereof to serve this purpose, said other means, of course, being appropriate to the type oi heater employed.

What I claim is:

1. In a steam heating system of the character described, the combination with a radiator equipped with a normally closed thermostatic air outlet valve, a steam generator including heating means, a room thermostat for automatically controlling the operation of said heating means to supply steam periodically to said radiator, and a riser through which steam is delivered to said radiator from said generator, of a dead end reservoir having an outlet communicating with the steam space of said generator, said air reservoir being directly heated by the boiler of said generator and also having an air inlet communicating with the outside atmosphere, and a valve controlling said air inlet and itself controlled by the temperature of said reservoir and its contents so that immediately upon a fall of the pressure within the system to a predetermined point slightly dlfie e29 below atmospheric pressure said inlet-controlling valve automatically opens to admit air to the system to break the vacuum therein and prevent opening of said radiator outlet valve so that the latter is maintained continuously closed during normal operation of the system.

2. In a steam heating system of the character described, the combination with a radiator equipped with a normally closed thermostatic outlet valve, a steam generator including heating means, mechanism for automatically controlling and operating said heating means to supply steam periodically to said radiator, and a riser through which steam is delivered to said radiator from said generator, of an air-heating reservoir consisting of a dead end length of metal pipe whereof one end is connected with, and communicates with the interior of, the upper portion of the boiler of said generator and whereof the opposite end is permanently closed, said pipe being provided intermediate its ends and at a redetermined distance away from said generator with an inlet, and a normally closed thermostatic valve controlling said inlet so as to open the latter for the admission of air to said pipe indep ently of said radiator valve and said mechanism whenever the pressure within said pipe falls to a predetermined'point slightly below atmospheric pressure thereby to supply preheated air to said boiler to break the vacuum within the system and prevent entrance of air through said radia tor outlet valve.

- CHARLES W. GRAVES.