US1824046A - Means for steam heating - Google Patents

Description

Sept. 22, 1931. J. 1 FITTs MEANS FOR STEAM HEATING' Filed June 10, 1927 Patented Sept. 22, 1931 UNITED STATES PATENT OFFICE JAMES LOGAN rrr'rs, or MERcHANrvTLLE, NEW JERSEY, AssIGNoR 'ro WARREN p WEBSTER a COMPANY, A CORPORATION oE NEW JERSEY MEANS FOR STEAM HEATING Application led June 10,

The object of my invention is to provide means for operating a gravity system of steam heating wherein the pressure in the return pipes may be definitely increased in an automatic manner at times when the boiler pressure exceeds the predetermined normal maximum for insuring the definite re! turn of the water of condensation into the boiler by gravity, notwithstanding the highig er boiler pressure which may temporarilyv exist therein. A

Heretofore, in modulation and other systems, the pressure of air derived fromthe condensed steam and accumulated in the 15 return side of the system has been reliedY upon to add to the pressure of the static head for insuring a more positive return of the water of condensation into the boiler when the pressure therein was in excess ofl zo that. which could be overcome by the static head alone, but the operation under these conditions was relatively slow and, therefore, would lagmaterially behind the sudden rises in boiler pressure Which might be induced by various causes; and it is, therefore, more particularly the object of my invention to provide special means by which external air may be admitted to the return side of. the system, under pressure. in an :v0 automatic and rapid manner, so as to promptly augment the pressure of the static head to counter-act the sudden increase in boiler pressure and insure the return of the Water of condensation to the boiler.

My invention consists in providing a gravity system of steam heating with means for creating air pressure and for automatically delivering volumes of such compressed air into the return side of the heating system under control of variations in the boiler pressure which may be in excess of the pressure of the static head normally relied upon for the return of water of condensation from-the return side of the system into the boiler, and in the preferred form of my invention, I provide means for maintaining a substantially constant air pressure and a pressure actuated mea-ns operated by the boiler pressure for admitting compressed air into the return side of the system, so as' 1927. Serial No. 197,843.

to be available for rapidly increasing the pressure upon the static head Whenever the oiler pressure exceeds the normal maximum.

My invention also comprehends details of construction which, together with the features above enumerated, are more fully described hereinafter and defined in the claim.

Referring to the drawings: Fig.. 1 is a diagrammatic eleva-tion illustrating the general arrangement of a steam heating system embodying my improvements and adapted for the carrying out of my improved method; Fig. 2 is a side elevation of a boiler with damper regulation and adapted for use with my improvements; Fig. 3 is a vertical section through the means for controlling the admission of compressed air to the return side ofthe system.; Fig.` 4 is a sideI elevation of a-vent trap for permitting es- ,-0 cape of air when the system is Working under normal steam pressures, but which automatically seals the air in the system Whenever the static head exceeds a predetermined level; and Fig. 5 illustrates a modification for admitting the su ply of compressed air to the return side o? the system under the control of the static head.

2 represents a steam boiler having the steam supply pipe 3 leading to the horizontal main 4 which supplies steam to the radiators 5 through modulation or steam control valves 6. The steam main 4 may be provided With the usual drip pipe 11 for returning the water of condensation to the g5 boiler. 'The Water of condensation, together with air, ma be delivered from the radiators 5 throng return pipes 8 delivering into the return main 9 which returns .the water of. condensation to the boiler through a suit- 9o able check valve 10. p

12 is a vent trap which is in communica tion with the return main 9 and acts as a reservoir at the top of the vertical portion of the return main in which the water content constitutes the static head, said trap being provided with a float 28 controlling a vent valve 29, the-construction being such that when the static head does not exceed the predetermined amount equal to the col- Vumn of water X above the water level in the boiler, the vent valve 29 is opento the atmosphere and permits the discharge of excess air from the return side of the system; but whenever the boiler pressure increases above the normalfthe static head rises and causes the float to seal the vent orifice and -prevent the escape of water and also retains the horizontal return main 9 by a branch pipe 13, so that the air space above the water in the trap is always in communication with the return pipes of the system above the level of the normal static head. The radiators are also provided with radiator return traps 7 through which the water and air is permitted to pass into the vertical returns 8 while restricting the escape of steam, such valves usually being thermostatically controlled, but may be of other forms such as float valves, if so desired. The system so far described is of the type known as a modulation system and is illustrated as typical of the class of s stems to which my improvements are app icable, though not limited thereto.

14 is an air reservoir and .is supplied with compressed air from a small compressor 39 which may be operated by an electric motor 40. The air reservoir 14 is connected by a pipe 15 with a differential control valve 18 so constructed as to automatically permit thel flow of compressed air from pipe 15 through pipe 17 and into the air chamber of the vent trap 12 whenever the steam pressure in the boiler is above the normal maximum. The

construction of the differential valve 18 is shownin Fig. 3, and consists of a valve 16 controlled by a differential diaphragm motor. More specifically, the valve 16 has its inlet connected with pipe 15, its outlet with pipe 17, and its thoroughfare controlled by a valve piece 23. ,The valve iece 23 is operated by a valve stem 22 exten ing downward and attached to a movable or flexible diaphragm 21 arranged within a casing and providing pressure chambers 19 and 20 respectively above and below the diaphragm,

the upper chamber 19 being in communica` tion with the pipe 17 and air space of the vent trap 12, and hence causes the pressure in chamber 19 to be substantially the same as the pressure in the return pipes of the system. The lower chamber 20 is in communication by a pipe 27 with the steam main 3 from the boiler, so that the pressure within said chamber at all times corresponds substantially to that in the boiler.

The diaphragm 21 is provided with a downwardly extending rod 24 passing through a suitable stufiing box and connected to a weighted lever 25, the weight 26 being capable of adjustment thereon to provide a constant downward pressure upon the diaphragm which, together with the pressure within the chamber 19, tends to close the valve 16 when the boiler pressure is normal.

When there is atmospheric pressure in the return pipes and no pressure on the boiler, the air valve 16 is closed by the action of the weighted lever 25 and the weight is so placed that it compensates for the desired difference between the boiler pressure and the return line pressure and its effect slightly exceeds the pressure difference between the normal water line of the boiler and the static head of water accumulating in the vent trap and which lifts the float 28 therein to close the air vent valve 29, so that the vent valve is automatically closed bc'forethe differentially operated valve 16 is opened. The position of the weight 26 controls the differential at which the compressed air valve 16 is opened and which differential, therefore, should be slightly greater than the static head. I

If the boiler pressure rises abnormally, the static head in the return pipe 9 and vent trap 12 is insufficient to return the water into the boiler against the boiler pressure, and vthis increased or abnormal boiler pressure is communicated to the chamber 20 of the differential valve 18, with the result that it overcomes the return pressure in the chamber 19 supplemented by the counterweighted 1ever25 and raises the diaphragm 21 to open the valve 16, permitting compressed air to flow from reservoir 14 through pipes 15 and 17 into the vent trap 12 and return side of the heating system, and provide therein an increased pressure upon the static head which, together with said static head, is sufficient to return the water of condensation to the boiler to the extent of the static head above its normal level. It will be understood that when this static head builds up in the return side of the system and before the valve 16 is opened to admit compressed air to the vent trap chamber, the float 28 has risen to such an extent as to close the vent valve 29 and thus cause the trap to receive and retain the compressed air so long as the static head continues above its normal level.

The compressor 39 may be of any suitable construction and driven by any suitable means for providing the necessary operative air pressure required,x but is preferably electrically driven by'a motor 40 receiving current from the electric circuits or mains 42 and putin and out of operation by a suitable switch or control means 43 actuated by a pressure motor 44 receiving its motive power from the compressed air reservoir 14 through a pipe 45, the construction being such that the compresser is put in and out of operation and, if desired, its speed varied under control of the pressure within the said reservoir In practice, I prefer to maintain the pressure in 'the reservoir 14 constant and Suthciently highto supplement the vstatic headpressure to .overcome or balance any abnormal steam pressure which might develop in the boiler. In this connection; it is pointed out that the maximum possible boiler pressure which could be made available before the admission of compressed air from the reservoir 14 into the return side of 'the system may be definitely provided for by the adjustment of the counterweight 26 on the lever 25 of the differentially operated air control valve 18.

It Will. be understood that the pipe 17 may connect anywhere with the return side of the heating system, so long as .it delivers the4 compressed air into the return side so it may be eti'ective in supplementing the static head therein, and have shown it as' delivering* into the vent trap 12 merely by way of example and convenient with the usual form of vent trap employed in practice.

It will also be manifestthat in place of a separate motor 40 being employed for operating the compresser, the latter may be operated rom any other source of power available, and the maximum pressure Within the reservoir or tank 14 may be controlled by any suitable means such as a spring actuated or Weighted safety valve where it is not desired tocontrol or vary the operation of the compresser.

In Fig. 2, I have shown a steam boiler provided with the usual draft. regulator 36 (receiving steam from the boiler by pipe 37) Which, through Weighted lever 35 and chains 32 and 34 respectively, controls the damper 30 for regulating the air supply under the grate and also the check damper 31 of the chimney 38, to maintain the steam pressure ofthe boiler Within reasonable normal limits.

Assumingthe apparatus to be normally operating to return. the water of condensatlon to the boiler by gravitv in connection with a static head (such as `X), and should the steam pressure from any cause rise abnormally, the static head will be increased and the vent trap through the action of the float 28 will become closed to the atmosphere, trapping the air inthe return lines and producing a slight counter-pressure. This air in the return side of the system and which partially fills the radiators is insufiicient to fully counter-balance the rise in the boiler pressure and,therefore, at this point the boiler pressure operating on the underside of the diaphragm 21 of the differentially controlled air admission valve device 18 exceeds the effect of the Weight- 26 on the lever 25 thereof and air from the compressed air receiver 14; is admitted through valve 16 to the return side of the system in such volume or quantity that the counter-pressure, 05 plus the static head, due to the Water'in the returns, permits the water of condensastantially constant differential between the pressure in the boiler and that in the return side of the system.

With the intermittent admission of the compressed or counter-pressure air, the Water of condensation in the returns would be returned to the boiler with greater constancy and with positiveness, irrespective of the higher steam pressure conditions, and such Water would not be heldin the radia- Y tors by a slight partial vacuum therein which might occur under other conditions, such vacuum being disturbed by the surge of air into and from the radiators through A a partially open trap and caused by the surges of air in the return lines (due to the operations of the differential valve 18), and 9 which would assistin causing the flow of Water from the radiators through the return traps thereon and to the vent trap on its way to the boiler.

In Fig. 5, I have shown a modification in the means for controlling the supply Aof compressed air to the return side of the systeln and which may be employed in lieu of the diil'erentially operated valve 18 shown in Cil Fig. 3. In this case, the compressed air pipe 17 may discharge directly int-o the vent trap 12 and its admission thereinto above the `Water level be controlled by a valve piece 16a operated by the float 28. This operation is such that as the static head is caused '110 to rise in the vent trap by reason of an increased boiler pressure, the valve 16a will admit compressed air into the return side ofthe system in proportion to the requirements, .the admission being greater when the static head rises higher due to an increase in the boiler pressure. The float valve 28 may also operate the vent valve 29 through a yielding spring device 29a, so that the vent will bc sealed before the valve 123 16a is opened to admit compressed air. It will also be understood that the vent valve may be operated as shown in Fig. 4 and an additional float employed to operate the valve 16m, but in any event, it is desirable lid' that the vent valve 29 shall be closed before the air supply valve 16a is opened. These valves may be arranged in any other suitable Way, so that When one closes the other opens, and vice versa. 13e

While I have described my invention in connection with the employment of compressed air as the medium to. be supplied `from the receiver or tank 14 into `the return side of the system for increasing the pressure therein in assisting the static head in returning the Water of condensation into the boiler, it is to be understood that the essential quality of the air which makes it suitable for this purpose is in the fact that air is non-condensible under the normal temperatures and pressures existing in an apparatus 'of this character, and I, therefore, do not limit myself to the use of air for this pur ose but include any suitable noncondensible gaseous medium which has substantially the same qualities as air in this Arespect and which, Whether air or other equivalent medium, may be designated as normally non-condenslble medium `at the pressure and temperature of a steam heat- .ing apparatus.

The exact mechanical constructions of the various parts may vary considerably, as I do not restrict myself to the form of compressed air controlling means or valves, nor to the supply and return valves employed in connection with the radiators; nor do I restrict myself to any particular details of the system, except so far as the return water of condensation isrequired to be delivered to the boiler by gravity and that when abnormal Steam pressure exists on the supply side of the system, means shall operate to' supply compressed air or gas independent of the steam boiler to assist the static head in overcoming the excess -pressurein the steam boiler and insure the Water of condensation being deliveredtlereto by gravity assisted by the increasedl ressure thus supplied to the return side o the system.

I have described my improved means 1n that form which I deem to be the best exposition of my invention and that which I prefer in commercial practice, but I do turn means under and in accordance with variations in pressure in the boiler to cause .a substantially constant pressure d1lferential to be maintained between the pressures in the supply side and in the return side of the system, said pressure difference together with the static head automatically causing the Water of condensation to pass into the boiler when the steam pressure therein is in excess of that required to maintain the predetermined normal static head, and in which the controlling means comprises a diaphragm motor having one side thereof in communication with the steam pressure on the supply side of the system and the other side in communication with both the return side of the system and source of compressed gaseous medium.

In testimony of which invention, I hereunto set my hand.

. JAMES LOGAN FITTS.

not restrict or confine myself to the minor or secondary details, as such are susceptible of modification, which may be resorted to as matters of mechanical skill and without a de arture from the spirit' of the invention.-

aving now described my invention, what I claim and desire to Secure by Letters Patent is:

In a steamheating system, a steam boiler,4 radiators supplied with steam therefrom, and returnmeans for returning the water of condensation to the boiler and maintaining in such return means a predetermined normal static head for causing the water of condensation normally produced to be delivered into the boiler by gravity and against a normal operative pressure therein, combined With a source of gaseous medium noncondensible at the temperatures and pressure of the steam in the system, means for de-

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