US2078775A - Control of heating systems - Google Patents

Description

April 27, 1937. K. W. n oHLlN CONTROL OF HEATING SYSTEMS Filed April 22, 1936 INVENTOR 127mm' WROLZL I 20a/wl, ATTORNEYS WN WW MW vPatentedv Apr. 27, 1937 lUNITED STATES PALEINTr oI-Flcflezvl CONTRQL HEATING SYSTEMS Karl W. Roblin, Merchantville, N. J., assignor to Warren Webster & Company, Camden, N. J., a corporation of New Jersey l Application April 22, 1936, Serial No. 75,681 8 Claims. (Cl. 237-67) This invention relates to heating systems and methods of controlling the same, and more particularly to the controlling of the generation and supplying of the steam from a boiler to a heating .system and the returning of the condensate from the system to the boiler.

'I'he invention is particularly adapted for use with relatively small steam heating systemsV ofthe class often installed in dwelling houses o r 10 other buildings having no cellar, i. e., Where the boiler is installed in a position at substantially the same elevation as some of the radiating units. With such installations some form of pumping means or the like is ordinarily provided for elevating or applying a pressure to the condensate returned from the radiating system, to the extent necessary to introduce such condensate into the boiler. The usual practice is to allow an appreciable quantity of such condensate to accumulate 'in a storage tank where it remains until thequantity is sufcient to operate a ioat control for starting a motor and pump for pumping the accumulated water intothe boiler. With such prior arrangements during the period that condensate is being accumulated in the storage tank, there will be a considerable lowering of the water level within the boiler. Then when the condensate return pump is put in operation and a tank full of accumulated condensate is pumped into the boiler, the water level in the boiler will rise to a somewhat abnormal height. Accordin'gly with such arrangements there is' danger that the boiler water level may at intervals becomevtoo low for safety, or if somewhat of an excess of'water has beenintroduced into the boiler. the water may at intervals become too high for eiicient generation and distribution of the steam. This invention according toone `of its phases provides a method'. and means for over- 40 coming these difhculties.

Heating systems of the above indicated character are customarily provided with motor driven oil burning apparatus or fuel stoking devices which may.: be -under the control of an indoor or outdoorgthermostat, whereby the fuel is fed for ring the boiler at spaced intervals, the intervals being `thus regulated thermostatically to meet the heating requirements of the system. As heretofore constructed, such systems have been provided with separate motors for driving 'l the fuel feeding device and the condensate return pump respectively, each of thesev motors being provided with individual control equipment. However,with the Apresent invention, accoming to one of its phases. a. single motor and a.

single thermostatic. control may be provided for both the fuel feeding device and the condensate return pump. 'I'hus the invention not only makes possible a substantial saving in the original cost of equipment, but provides in general a 5 greater accuracy of regulation, with the ring of the boiler and the return of the condensate conforming more closely vwith variations in the heating requirements. The invention also avoids interruptions or delays in the response of the 10' heating system to the thermostatic control.

Various further and more specic objects, features and advantages will clearly appear from the detailed description given vbelow 'taken in connection with the accompanying drawing form- 15 ing a part of this speication and illustrating by way of example a `preferred embodiment of the invention. The invention consists in such novel features, arrangements, combination of parts and methods as are described in connection 20 withthe apparatusherein disclosed by way of example only.

Fig. 1 illustrates a typical form of heating system embodying the invention; and

Fig. 2 is a vertical sectional view showing one example of a condensation return pump adapted for use with the invention.

In Fig. 1 a steam heating boiler is indicated at Ill and to which is connected a steam supply main at II. A plurality of radiators as at I2, I3 30 I,

and I4 may be connected to the steam main by steam supply pipes as at I5, I6 and Il having radiator inlet valves of a well-known form as at I8. The outlets of the radiators may be provided with any suitable well-known forni of radiator 35 trap as at I 9 through which condensate may pass to condensate return pipes as at 20, thence to a condensate return main as at 2|. This return main may be provided with -a well-known form of vent trap as at 22. Such a vent trap may for 40 example be provided with a vent opening at a point normally above the water level in vthe boiler. Such vent, however, is capable of being closed by a oat controlled valve whenever the condensate in the return piping exceeds a pre- 45 determined level. As shown, the vent of this trap may also be provided with a ball vent valve 23 which is normally closed, but which will permit air or vapor to escape whenever the pressure above the water in the trap exceeds atmospheric 50 pressure by a small amount. And whenever the 'pressure conditions in the radiating system and return piping are sub-atmospheric, the ball vent valve remains in closed `condition whereby a partial vacuum may be maintained in the system. u

A condensation pump is indicated at 24 for pumping condensate from the return main through a.' conduit 25 into the boiler. Check valves 26 and 21 as shown may be provided 'in the inlet and outlet connections of the pump 24. The pump may be connected to the return main through a lift fitting as at 28 to insure that the pump will have access to the lowest part of the return main and so that water Will be available for the intake of the pump, free of air or vapor so long as there is any substantial amount of condensate remaining in the return main.

The boiler may be provided with any suitable well-known type of fuel feeding device 30 such as an oil burner or stoker driven by a motor 3|. A source of electric power for the motor is indicated at 32. A thermostat may be provided as at 33 either indoors or outdoors for controlling the operation of the motor 3| in a wellknown way through electrical connections as at 34 supplied with current from the power source 32 through a transformer 32.

The motor 3| may be connected by a shaft 35 and resilient connection 36 to a drive shaft 31 for the condensation pump 24. Accordingly, whenever the motor of the fuel feeding device or oil burner is started in operation by the action of the thermostat, the condensation pump will be concurrently started and whenever the thermostat acts to shut off vthe fuel feeding device, the rpump will be stopped at the same time. Thus a single control device and a single motor may be used for both the fuel feeding device and the condensation return pump. Furthermore, both the fuel feeding device and pump will be operated concurrently at spaced intervals with several advantageous results, as will be explained hereinafter.

The operation of thel system may be described as follows. When the temperature at the thermostat 33 drops, an electrical circuit will be completed through the thermostat, and current from the transformer 32 will serve to actuate any well-known form of control device such as a relay which may be provided at the oil burner for starting the operation of the motor 3| with power from the source 32. Thereupon, fuel is fed into the fire box of the furnace and burned in the usual way. Simultaneously with the starting of the motor 3|, the condensation pump 24 will be starting for withdrawing water that has accumulated in the return piping and discharging such water immediately into the boiler, insuring substantially a maximum height of water in the boiler before the boiler is brought up to a temperature causing the generation of steam to begin. Continued operation of the fuel feeding device results in the generation of steam which is quickly condensed in the radiating system. The resulting condensate ows down the return piping to the condensate pump, which continuously lreturns such water to the boiler during the firing period. When the spaces heated by the system reach a predetermined temperature, the thermostat 33 causes the current to be cut oi from the motor 3| which results in stopping the motor and the feeding and burning of fuel in the furnace, as well as concurrently stopping the return of condensate to the boiler.

Thereafter the generation of steam will continue for' a period due to the induced vacuum preserved in the system by reason of the fact that the ball vent valve 23 will then be tightly closed.

The condensate resulting during this period, which will be relatively small in amount, accumulates ln the return main where it remains until the thermostat again starts the fuel feeding device and condensation pump. However, the loss of the slight quantity of water from the boiler during the period of inaction of the pump is of no consequence, because the oil burner or stoker is then not in operation, so that even a large loss of water from the boiler temporarily during such period would not be harmful.

At the beginning of the next cycle of operation the water stored in the return main is returned to the boiler as above described.

It is apparent that with the above described equipment, it is unnecessary to provide any tank for accumulating the condensate returned from the system, and neither is it necessary to provide any float controlled switch or other equipment such .as is necessary with such tanks. The above described equipment not only avoids the necessity of using a separate motor for the condensate pump, but despite the elimination of a tank for accumulating the condensate, it is unnecessary to operate the motor during any larger proportion of the time than such motor is operated for the pupose of driving the fuel feeding equipment. .Thus the arrangement is very economical in the use of electric current.

Since this system` synchronizes the return of water to the boiler with the generation and discharge of steam from the boiler, it insures that the desired predetermined water level will be steadily maintained in the boiler and at the same time avoiding the injection of large quantities of cold water into the boiler from time to time, which would interrupt the steaming period and interfere with proper thermostatic regulation of the system.

Fig. 2 illustrates a form of condensation return pump particularly adapted for use with the above described system. This pump may comprise a piston 40 reciprocating in a cylinder 4| communicating with the condensate return conduit 25 at a point between the check valves 26 and 21. The piston 4D may be operated by a connecting rod 42 which in turn may be pivotally connected as at 43 eccentrically with a worm wheel 44 mounted on a shaft 45. 'I'he worm wheel 44 may be driven by a worm gear 46 mounted onthe pump shaft 31.

The various parts of the pump may be mounted within a'housing 41 as shown, which is designed to contain a body of oil as at 48. An oil settling chamber 43 may be provided within the lower part of the housing 41 communicating through an opening 50 with the main body of oil at 48. The chamber 49 may also communicate through an oil line 5| with a nozzle as at 52 lfor discharging oil on to the worm gearing and other moving parts. The oil may be caused to iiow up through the oil line 5| by pressure created by an oil plunger 53 reciprocating within the opening 50. The plunger 53 may be attached to reciprocate with the pump piston 40 vas shown. Y 'I'he worm wheel may be accompanied by a flywheel as at 54 to insure uniform operation of the pump.

Suitable 'packing of well-known form may be provided as at 55 around the piston 40. :Any water which escapes past such packing may be retained within a groove 56 surrounding the upper part of the piston. Such water may be drained o through apertures as at 51 and 58. The upper end of the piston 4|) may be providedv with a shield 53 for preventing oil from dropping into the water within the groove 56. The chamber 49 may be also connected with the main body of oil 48 through a check valve 60. The oil line 5I' may also be provided with a check valve 6i.

While the invention has been described in. de-

tail with respect to particular preferred examples, it will be understood by those skilled in the art after understanding the invention, that vatime occupied by such intervals, and forcing sub-- stantially all of the condensate returned .from

the radiating system into the boiler during said intervals of firing. Y

2. The method of controlling the generation and supplying of steam from a boiler to a heating system, and returning the condensate from the system to the boiler, which comprises firing the Aboiler during spaced intervals of time, regulating the proportion of elapsed time occupied by such intervals whereby steam is provided substantially in accordance with the systems heating requirements, and forcing substantially al1 of the condensate. returned from -the system into the boiler` during said intervals of ring.

3. The method of controlling the generation and supplying ofv steam from a boiler to a heating system, and returning the condensate from the Vsystem to the boiler, which comprises 'firing the boiler during spaced intervals of time, regulating the proportion of elapsed time occupied by. such intervals whereby steam is provided substantially in vaccordance with the systems heating requirements, forcing substantially all'of the con- -densate returned from the system into the boiler during said intervals of firing, and maintaining a sub-atmospheric pressure in the system during a substantial part of the time between said intervals.

4. The method of controlling the generation and supplying of steam from a boiler to a heat,-

ing system, and returning the condensate from the system to the boiler, which comprises firing the boiler during thermostatically controlled' spaced intervals of time, permitting the condensategzto `return by gravity and accumulate at a low p/pint in the system during times between intervals of ring, and forcing such accumulated.

condensate into the boiler during spaced intervals, the intervals of i'lring and the intervals of forcing the condensate into the boiler being initiated substantially concurrently'.

5. The method of controlling the generation and supplying of steam from a boiler to a heat'- ing system-and returning the `condensate from the system to the boiler, which comprises firing the boiler during thermostatically controlled spaced intervals of time, 'permitting the condensate to return by gravity and accumulate at a low point in the system during times between intervals of ring, also permitting a subatmospheric pressure to be induced in the system during said times, and forcing such accumulated condensate into the boiler during spaced intervals, the intervals of firing= and the intervals of forcing the condensate into" the boiler being initiated substantially concurrently.

6. The method of controlling the generation and supplying of steam from a boiler to a heat-v ing system, and returning the condensate from the system to the boiler, which comprises firing the' boiler during thermostatically controlled spaced intervals of time, permitting the condensate to return by gravity and accumulate at a low point in the system during times between intervals of ring,and introducing such accumulated condensate into the boiler during spaced intervals, and causing each of said last named intervals to occur substantially during an interval of firing.

'7.- A steam heating system comprising radiators, a boiler, steam supply conduits for connecting said boiler to the radiators, return conduits for conveying condensate from the radiators to a point in the system below the normal water line in said boiler, means in said return conduits to prevent passage of steam therethrough, a pump for forcing the condensate from said point into the boiler, a fuel feeding device for the boiler, means'for starting and stopping said fuel feeding device at intervals depending upon the heating requirements of the system, said means also being operatively associated with said pump whereby said pump operates to return .condensate to thelboiler only during intervals which occur substantially during intervals of rving, and means for discharging air from said diators, a return conduit system for conveying condensate from the radiators to a low point in the system below the water lineV in said boiler, means in said return conduits to prevent passage of steam therethrough from the radiators, a fuel feeding device for the boiler, means for operating said device during periods alternating with intervals of non-ring, .the relative duration of said intervals and periods depending upon the heating requirements of the system, the return conduit system` having sufiicient Ycapacity at and adjacent said low point to receive and retain the condensate returned -during each of said intervals, a pump for forcing the condensate from said low point into the boiler, said last named KARL W. ROHLIN.

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