US2346890A - Steam heating boiler control - Google Patents

Description

April T. w. H. ABBOTT ,346,

STEAM HEATING BOILER CONTROL Filed March 11, 1942 3 Sheets-Sheet 1 Illlll Ill l lllllll v April 18, 1944.

w. H. ABBOTT STEAM HEATING BOILER CONTROL Filed March 11, 1942 3 Sheets-Sheet 2 ML YTHOMA$ HQABBoi-T @MJFM Apnl 18, 1944- T. w. H. ABBOTT STEAM HEATING BOILER CONTROL Filed March 1'1, 1942 5 Sheets-Sheet 3 TO RADIATORS T9 (ATE-1'? on: BQILELR gwuc/vvtoz TH MAs W. H. Aseo r- Patented Apr. 18, 1944 UNITED STATES PATENT OFFICE 7 2,346,890 STEAM HEATING BOILER CONTROL Thomas w. H. Abbott, Baltimore, Md. Application March ll, 1942, Serial No. 434,183

6 Claims.

The invention relates to a steam boiler control system principally for use in the heating of apartments, industrial plants and the like, though it is also adapted to smaller installations, as in private residences.

The system as a whole, its various elements being interdependent but also capable of separate use, comprises in connection with a steam boiler cf the type suggested or other suitable steam boilers with steam radiators, a float controlled condensate return valve, a float controlled feed water valve, the floats for both valves being located in the horizontal plane of the normal water level in the boiler, and a free flowing air vent preferably of the balanced type, arranged to admit air to the boiler whenever the pressure drops below normal. This system being usually operated close to or preferably a little above atmospheric pressure. It is conceivable that for some purposes, the system may be arranged with suitable modification and equipment to operate at other pressures, the purpose of the air valve being to cause the water level at the location of the floats which control the condensate return valve and the feed valve to conform to the water level in the boiler, preventing over feeding due to vacuum in the boiler.

The purpose of the condensate return valve is to prevent backing up of water into the radiators and the return pipe and other pipes leading to the radiators. It maybe employed without an automatic feed. The purpose of the feed water valve is to prevent overfeeding and, hence, filling of the steam space in the boiler and in the radiators with water and also toprevent feeding of water to the boiler through the automatic feed when the waterlevel has in someway become so low as to tend to cause overheating, so that an influx of cold water would result in an explosion.

The prior apparatus includes check valves intended to prevent backflow of the water toward the radiators and it also includes feedwater valves which are float controlled, but the check valves in the prior apparatus have not been elfective to prevent back flow of the water through the condensate return pipe to the radiators, nor have the previous types of feedwater valves been effective to prevent over feeding of water to the boiler,

filling the steam space and tending to enter the radiators with harmful results, which are so well understood as not to require discussion.

The practical inoperativeness of the condensate return valves of the prior constructions is partly due to clogging of the seats with sediment from the boiler and from other sources, and partly due to failure of the valves to properly register with their seats, and failureof the valves to seat quickly in response to the back flow of water from the boiler. Frequently the cause of the failure of the feedwater valves of the prior art has been the false water levels in the float chamber resulting from the creation of a vacuum in the boiler or sudden loss of pressure which tends to prevent the water in the float chamber from seeking its gravity level, and hence, failure of the body of water in the float chamber to correspond as to the level of its surface, to the level of the water in the boiler. This unsatisfactory operation is also due to failure of the valves to seat because of unsatisfactory valve gear, and in some instances to the location of the feed water valve float in the path of the returning condensate whereby'the position of the float was disturbed so that it failed to conform to the water level in the boiler.

All of these difficulties have been overcome in and by the apparatus hereinafter described which has been found to operate perfectly for periods of indefinite length, giving completely automatic regulation of the water level in the boiler, as well as complete absence of flooding of the boiler and radiators by overfeeding and complete absence of backflow through the condensate return pipe, the radiators being practically dry at all times. The boiler is also fully protected from the feeding of cold water when heating may have occurred due to reduction of the waterlevel.

In the accompanying drawings I have illustrated a boiler feed water and condensate return control system embodying the features of my invention in the preferred form in the drawings:

Figure l is a vertical section on the axis of the float casing or chamber containing the float which controls the feedwater valve and also containing the float which supports the condensate return valve, and at the topof this chamber is the condensate return valve chamber and valve, and the section also intersects the feed valve chamber and gear casing'on a central vertical plane.

Figure 2 is a section through thefloat chamber looking downwardly from line 22. in Figure 1, the scale being reduced Figure 3 is a horizontallsection looking downwardly from the line 33'in Figure .1 and illustrating the feedwater valve gear.

Figure 4 is a horizontal section on the line 4-4 in Figure 1. I I

Figure 5 is an elevation partly insection show ing the air relief valve casing and mechanism, the said view being broken away intermediately and including the connection to the boiler.

Figure 6 is a horizontal section on the line G-& in Figure looking downwardly from said line and showing the valve stem and balancing mechanism in top plan.

Figure 7 is a diagrammatic View of twin boilers to which the control is applied showing the connections including the feedwater pipe and the condensate return pipe and the casings of the various valves above referred to.

Figure 8 is a section corresponding to Figure 1, showing a form of the device in which the condensate return control valve chamber and float chamber are separate from the .feed water control float.

Figure 9 is a section through the on the line 99, Figure 8.

Figure 10 is a diagrammatic view corresponding to Figure 7 showing the use of the valve, Figure 8, independently of the feed.

Referring to the drawings by numerals, each of which is used to indicate the same or similar parts in different figures; the construction shown comprises a pair of boilers I and 2, illustrated in connection with an installation to which the invention has been applied, the system being of the gravity type, the pressure being normally about 2 lbs. above-atmosphere and dropping periodically to and slightly below prevailing atmospheric pressure. The steam and condensate return pipes are indicated at 3 andA respectively, the radiators being above, and connected in the usual manner to both pipes. This installation has been referred to as a dry system because of the absence of water from the radiators.

The system as illustrated also includes an automatic pressure control 5. connected to the steam chamber of the boiler by a pipe connection 6 and serving to open and close a damper or draft I in any suitable manner as by means of a flexible connection 8. This control serves to open the damper and increase the fire when the pressure drops to or slightly below atmosphere. suitable equipment for adaptation of the system it may be applied to systems operating at other pre The air or vacuum breaking valve casing is indicated at 9.

The casing enclosing the condensate return valve and feed-water valve float is indicated at It! and the feedwatervalve casing also enclosing the operating lever mechanism is shown at H, being connected directly to the casing Hi. Pipe I! is a by-pass.

It may be noted that the condensate return pipe 4 extends downwardly or is looped downwardly at l2, extending below'the water level in the boiler and well down toward the bottom of the boiler and then extends upwardly at M and vertically downwardly into the top of the chamber or casing IS. The low point of the chamber or casing ill at I5, is connected by a pipe IE to the boiler the pipe [6 being connected directly'to the water space of boiler l The details are for illustration only, the system being capable of considerable variation. The boilers and 2 are connected below water level by pipe 11 and there is a feed connection for special use as by means of a hose at H3.

Referring now to Figures 1,2 and 3, the condensate return valve and feed valve float chamber is indicated by reference character 29 being connected at its lower end-to the pipe l6 which valve chamber.

W ith leads downwardly to the water space of the boilers and 2, preferably at a low point. The casing is connected above to the pipe 4 which leads downwardly into the top of said casing H], particularly into return valve chamber 21.

The condensate return valve 2| is shown as of the universal type having a downwardly disposed seat 22 at the lower end of pipe 4, which is preferably of the shape of a spherical section. The direction of the inflowing condensate return water tends to keep both the valve seat and the valve surface free of sediment. The valve 2| is preferably open below and concave at 24 to assist in seating the valve in case of a sudden influx of water from the boiler by way of pipe l6the primary purpose of said condensate return valve being to prevent the backing up of water from --the boiler into the radiators, also to open freely to permit the return of condensed water to the boiler whenever the accumulation of the condensate and the condition of the boiler pressure will permit.

While many of the details are of importance, they are subject to variation and rearrangement. The valve 2| is carried by a float 25 which, as shown, is cylindrical and upright as to its axis, the float being shown in depending relation to the valve and located in the vertical tube 26 which is open at both ends, The valve 2| is located in a funnel like chamber 21, to which the tube 261s secured at its upper end being shown as extending downwardly from the casing which is open downwardly into the tube. The valve 2| is in its low or widest open position supported by upright radial fins 28 which are located at the bottom of the chamber 21 being shown as extending horizontally inwardly to the plane of the inner wall of tube 26. The condensate return valve, member 2|, as shown, as thus supported, is free to respond to the back flow and to conform to the seat 22 under any and all circumstances. The float 25 which lifts the valve toward its seat when the water rises in the tube 26 due to sudden increase of l pressure in the boiler is entirely free of the tube 26 which is much larger than the float 25, the tube 26 being of much greater diameter than the float 25.

The float chamber or casing 20 also contains an annular hollow float 29 having a central opening, 30, which as shown contains or encloses the tube 25, being of considerably larger cross section than the tube 26, thus the float 29 is free to rise and fall without restraint from this source,

In the normal position of the float, its central horizontal plane is at the plane of the normal level in the boiler. This planemay be somewhat above the section line 2-2 in Figure 1. In fact for the purposes of this description, the position of the float valve 29 shown in Figure 1 may be treated as corresponding to. the normal water level in the boiler, the central horizontal plane of the float being at said water level.

The float 29 is providedwith a depending or downwardly extending stem or operating rod 3|, the stem or rod 3| extends downwardly into the sub-chamber 32 of the float chamber 20, which sub-chamber is connected at 33 to the feed water valve and gear casing I.

It may be noted at this point that the feed water pipe 34 preferably leads in a downward direction into the casing H and that the seat 35 of the feed water valve 36 is downwardly disposed the feed water valve in turn indicated. at 31 being upwardly disposed and seating upward;

13'. The feed water valve 37 as shown has a downwardly spaced guide 38 and a depending shank 39 extending through said guide. Said shank 39 is apertured horizontally at 40 to receive a normally horizontal valve lever 4| which in the form shown is pivoted at 42 at the right and extends horizontally to the left through the opening 40 which is shown as enlarged relatively to the cross section of the lever 4| and curved as to its upper and lower walls, said walls being convex inwardly as at 43.

-In the prepared form shown the pivot 42 is adjustably mounted on a screw shank 44 which is threaded upwardly through the top wall or cover I l of easing I l and provided with an external engageable portion 45 and packing nut 45'. The lever 4| rests at its outer end upon an actuating lever 41 which as shown is pivoted at '48 on an adjustable vertically slotted bracket 49, said pivot 48 being intermediate of the length of the lever 4| and located between the shank 39 and the ball like head 50 at the outer or left hand end of valve lever 4|, remote from pivot or fulcrum 42.

The actuating lever 4'! extends to the left from its pivot 48 into the subchamber 32 of valve cham ber 20, where it is provided with a fork 5! which straddles the lower end of the stem 3| between adjustable abutment collars 52 and 53 which engage the actuating lever 47, raising its forked end 5| and lowering it or permitting it to descend as the float 29 moves up and down with the change of level of the water in the float chamber 20.

The actuating lever 41 is provided at the right in Figure 1, with a rearwardl extending arm 54,

the direction of the first mentioned arm 55 to the left being treated as forward. The length of this rearwardly extending arm 54 which terminates in a ball-like portion corresponds to th spacing of the ball 59 on the valve lever 4| from said pivot 48 in a horizontal direction and to the spacing of shank or stem 39 from the pivot or fulcrum 42.

Float control feed valves of this and other types intended to permit or control feeding of Water to a boiler whenever the water level drops below its predetermined normal, previously known have proved unsatisfactory because of the tendency to overfeed and fill the steam space in the boiler and part or all of the steam space in th radiators and steam pipes with water. the creation of a vacuum or to reduction of pressure in the steam space and in the radiators which is generally due to condensation in the radiators when the fuel gets low or to a more or less sudden reduction of the boiler temperature as in the feeding of coal to an overfed furnace. Such reduction of temperature causes quick condensation with a correspondingly quick reduction of pressure to or below atmospheric pressure, the pressure in the boiler being thus reduced below that in the float chamber where air is at atmospheric pressure or at slightly higher pressure, pocketed, or a column of condensate has accumulated in the return pipe 4. This difference in pressure between the boiler and the float chamber causes a lower water level in the float chamber or casing 20 than that existing in the-boiler. This may be referred to as a "false water level" in the float chamber. This false water level being but slightly below normal prevents the feed water valve from rising to the level of the water in the boiler and thus causes feeding of water to the boiler Without regard to the existing water level therein so that with anextended period of vacuum in the boiler the steam space may be almost com- This is mainly du to r pletely filled, frequently backing the water up into the radiators, a condition which is known to have objectionable results.

In the present system this difiiculty has been overcome by the provision of a free flowing air valve, preferably the balanced type so that it may be adjusted to admit air freely to the boiler when the pressure goes below atmospheric or otherwise below normal. While this valve is intended to be used to admit air at atmospheric pressure, it is conceivable that it might be used with boilers working at higher pressures by connection of the valve to a supply of air or other gas under suitable pressure. This valve is preferably mounted directly on or connected directly to the boiler to provide a free flow of air and thus to accomplish practically instantaneous filling of any vacuum which may occur in the boiler, hence equalizing or substantially equalizing the water level in the float chamber with that in th boiler. While the valve as shown is mounted directly on the boiler, and it is believed to be best located in that way, it may be connected by a pipe which is to the best advantage so arranged as to g ve the inimum of friction incident to the flow of air and hence to give quick equalization of the pressures. A form of air valve suitable to the system is illustrated in Figures 5, 6 and '7.

The air valve assembly -60 comprises a casing 9. This casing contains a downwardly disposed spherical seat Bl, formed on a valve seat insert 62, threaded into an upwardly disposed opening in said casing, indicated at 63. This opening is'provided with a perforated upright turret 64, which surrounds the opening and extends upwardly therefrom, the perforations 65 being near the top, and protected by a cap or mufiler 66, of larger diameter than the turret '64, and having a depending skirt 6'! surrounding the turret 64.

The casing 60 also encloses a valve member 68 cooperating with seat 6|. This valve as shown has its seating surface in the form of a spherical section and provided with a depending stem 69 which as shown is controlled by guides 10 and Hi. The valve stem 69 is shown as provided with upper and lower opposite rounded abutments II. The valve or valve member 68, with its stem 69, is carried by a balance lever 12, pivoted near its center, as on horizontal transversely extending knife edges 13, which engage knife edge seats 14 removably mounted in the casing 60 as on screw carriers 14' as .best shown in Figure 6. The lever 72 is forked at one end at 15 to straddle the stem 69 between the abutments II and arranged to engage the upper and lower abutments alternatively.

The lever 12 and valve member 68 are shown as balanced by a weight 16 adjustably mounted on the end of the lever which is opposite to the fork 15. As shown the weight 16 is threaded on the end of the lever arm, and held in position by a lock nut ll-the details being subject to variation without departure from the principles of the invention. 7

It should be noted that the air valv casing 69 is connected to the steam space of the boiler by a pipe 79 of sufficient cross section to provide a free flow of air to the boiler in response to each drop of pressure. The valve member '68 is preferably open and hollow or concave beneath at 62' to provide for pocketing the back flow to give quick closing to prevent escape of steam. The operation of the control will be more fully discussed in connection with the complete disclosure.

Figures 8, 9 and 10 relate to a system in which the condensate return valve is separate from the feed water control in which the feed of water to the boiler is controlled by hand or by some other means not directly combined with the return of the condensate to the boiler.

Figure shows diagrammatically a steam heating system having a boiler, 99. This boiler is connected by one or more steam pipes 8i to the steam radiators in the building not shown. The illustration also includes a pressure controlled regulator 82, connected to the steam space of the boiler by a pipe 83 to receive pressure therefrom and to the draft or damper 84 by a flexible member 85, any control being usable for this purpose. Illustration Figure '7 is for example only.

The system also includes condensate return pipe 89, leading downwardly to a low point 81, which is preferably near the bottom level of the water in the boiler as shown at 88, and upwardly to a high point 89 above the water level in the boiler, and then downwardly entering the top of the condensate return valve casing 99. From the bottom of the casing 90, a pipe 9! leads downwardly entering the water space of the boiler at a low point as indicated in 92, which is near the bottom of the boiler. There is also a by-pass connected around the casing 99, as indicated at 93. The various connections in the diagram and in the diagram Figure 7 are supplied with suitable shut-off valves as in other systems of this general type. Figures 8 and. 9 show the condensate return valve assembly 99. The valve member 99 is mounted in the chamber or casing 99, and connected to the radiators by the condensate return pipe 89, leading downwardly to the top of the casing 94, and by a return pipe 9|, leading to the water space of the boiler at a low point 92.

The pipe 86 leads downwardly from high point 89 to and through a valve seat which may be formed on the valve seat ring 95. On the lower face of this is formed a downwardly disposed valve seat 99. This seat as shown, is a spherical section or zone and cooperating with this seat is a poppet valve 99, having an upwardly disposed valve seating surface 91, shown as in the form of a spherical section. This valve 99 is preferably concave beneath as at 98 and open to assist in immediate closing by lifting the valve toward the seat in case of a sudden tendency to back flow on account of increased pressure in the boiler or an influx of feed water. The valve member 99 is provided witha depending valve supporting fioat 199, shown as of cylindrical form and extending downwardly within a tubular portion Ifil of said casing 99, to the bottom of which return pipe 9I is connected.

In the form shown the portion of the casing 90 beneath and surrounding the seat 99 and valve member 99, is in the form of a frusto-conical funnel member I92, this arrangement and other details are subject to variation, the purpose being to provide an easy down flow of the water from pipe 89 through the seat 96 to and around the valve, and beneath the'same to the tubular portion WI and downwardly to casing 99 and through same to the boiler.

The valve member 99 is shown as supported in open position by means of radial fins I93, which are spaced about the chamber I92 at the bottom thereof and extend upwardly to a sufiicient degree to provide a free flow of water past the valve in its lower and most widely open position.

A feed water inlet to the boiler is shown at the left in Figure 10 at I94. This may be hand controlled or any suitable automatic feed may be employed. In the various forms of the invention, there may be a drain cock I05, in the condensate return pipe at the bottom of the loop. The main purpose of this is to provide for the release of sediment from the radiators and boiler which in existing systems tends to accumuate on the seats and valves and prevent satisfactory closing.

In the operation of the system, reference being had first to Figures 1 to '7, the condensate from the radiators, the pipe 4 being connected to a low point of each radiator in the system, flows downwardly through the valve seat 22 which may be formed on the insert 23. From seat 22 it flows to and through the chamber 21, the valve 2| being open and downwardly through the tubular fixture 26 into the chamber 20. Assuming that the pressure in the boiler is low at this time the condensate tends to flow through the pipe I6, to the water space of the boiler. From time to time a column of water may accumulate in the pipe 4, and when the pressure in the boiler drops to or below atmosphere or below normal boiler pressure due to consumption of the fuel supply in the furnace or to feeding of coal to the top of the fire, there may be a rush of water downwardly through the seat 22, which, if it were permitted to contact the feed water control float 29, would change its position so that it would not correspond to the water level in the boiler and hence would interfere with the regulation and control. of the feeding of water to the boiler at water level below normal,

The installation as shown in Fig. 1 has the advantages of a single float valve chamber for the feed water return valve, and the feed water control valve, and it is important that the condensate in returning through the combined float chamber passes through tube 26 in the opening 39 in float 29 and does not interfere with the conformation of the feed water control float to and with the level of the water in the boiler as transmitted to the float chamber, and hence does not interfere with regulation of the feed.

It is also to be noted that the condensate return valve has its seat downwardly disposed with the water flowing downwardly therethrough so that the sediment which accumulates to a considerable degree in the radiators, tending to return with the condensate, does not accumulate on the seat and further the downward flow of the water over the valve seating surface at 2| tends to clear the valve surface of sediment. It is also of interest that the valve and the seat 22 are preferably of the universal type so that the cocking due to side pressure on the valve or any slight disalignment does not prevent it from engaging the seat and forming an effective closure. Further, the valve is free to move vertically to and from its seat in opening and closing the float 25 being considerably smaller than the tube 26 which serves a guiding function to a sufficient degree to keep the valve 2| in approximate al gnment with th at and hence in seating position.

It is also notable that the valve 2I supported by the float 25 moves upwardly toward its seat whenever the water in the tube 26 rises to the proper point or there is a tendency to back flow of Water into the radiators, and this valve is caused to contact its seat due to difference of pressure, i. e. vacuum in the radiators, as well as buoyancy so that there is no possibility of back flow of water to the radiators and the water is discharged from the radiators into the boiler Whenever it accumulates, even" small quantities, provided there is a drop in" pressure in the boiler which permits opening of the valve 2|. Such reduction of pressure is bound to occur at comparatively frequent intervals due to variation of the fire or feeding of coal to the top of the fire, the overfeed type of furnace being generally used, and even with other types of furnace, there is sufficient variation to permit the condensed water to return to the boiler with sufficient frequency to keep the radiators free of Water, The down flow through the downwardly disposed seat is effective in clearing the seat and valve of scale and sediment from the boiler and radiators and the spherical contours of the seat and the seating surface of the valve contribute to the effectiveness of the closure.

The condensate return valve is in many ways independent of the control of the feed water and for this reason it is shown separately in Figure 8 in connection with a boiler, which may have the water fed to it by any method, either hand controlled or controlled by any device separate from the condensate return control valve.

The illustration, Figure 1, includes, as already pointed out, the combined float chamber 20, and feed water valve casing H, the float chamber contains float 25 which supports the condensate return valve 2|, and also contains the float 29 which controls the operation of the feed water valve 3'! through and by way of the feed water valve operating assembly 33 in the chamber II.

The feed Water valve seat 35 is preferably downwardly disposed, being fed from a water pressure supply pipe 34, and the valve 31 closes upwardly into contact with said seat. The feed water control valve float 29 in the form shown has a depending stem 3| secured to and extending down from a spider 23 which is secured-to the bottom of float 29, spanning the opening therein, the float being for the purposes stated, preferably an annular float permits the condensate return to pass therethrough. The condensate return valve float may, however, be placed in a separate chamber, the construction shown having the important advantage of simplicity of installation and compactness.

The depending stem or rod 3| of float 29, in the form shown engages the control lever 55 by way of upper and lower abutments 52 and 53, which are spaced apart whereby the motions of the float are communicated in modified form through the lever 55.

In accordance with the preferred operation, the feed water valve 31 is closed when the float 29 moves above its mid-position in correspondence to the normal water level in the boiler thus preventing overfeeding and it is also closed when the float sinks below the normal water level in the boiler as communicated to float chamber 20, thus preventing feeding of water to the boiler when the recession of the water to a dangerous low point may have caused overheating of exposed parts of the boiler as the crown sheet;

Such feeding of water to the boiler when thus overheated is probably the commonest cause of boiler explosion, or at least it is a fruitful cause of such explosions.

There may be a degree of lost motion between the abutments 52 and 53 and in the forked end of the lever 41 which may permit slight variations of position of the float without change of the position of the valve or of the lever 41.- Mainly it provides freedom of the feed valve operating mechanism. The valve operating leverdl being pivoted at one end and connected intermediately of its length to the lever 31 as by opposite abutments 43 and resting at its extreme outer end at 50 on th lever 41, between its pivot 48 and the fork 5|, i raised closing the valve 31 when the float 29 rises above the position corresponding to normal water level in the boiler when the water level drops slightly below normal lever 41 is lowered, lowering the end 58 of valve lever 4| causing'the valve to be opened to admit Water to the boiler from the feed pipe 34, and in the extreme low position of the float 29, the arm 55 of operating lever 47 moves downwardly raising the rear ball like end 54 of lever ll on the opposite side of pivot 48 from the fork end 5!, to contact the valve lever M from beneath, raising the same and closing the valve 3'5. This only occurs when the water level has dropped to a danger point where overheating with danger of explosion due to introduction of cold water would result. This condition is of most infrequent occurrence, the system being capable of completely automatic operation for periods of a month and longer.

When this position of the parts has been reached and the valve 31 has been closed, no water can be fed to the boiler unless it be with the full knowledgeand intent of the operator using a hose or other special equipment provided for this purpose as suggested at H3. Thus the attention of operator is calledto the condition of the boiler causing him to take the necessary precautions. It is to be noted'in this connection that when the water reaches such low levels the condensate will have been pre-' viously drained from the radiators and there is little water to be returned to'the boiler at this time from the condensate returnline. In fact, the heating system to which the control has been applied in the disclosure, is known as a dry open system in that the radiators and steam pipes are practically dry at all times and free of condensed water as well as back flow, the condensed water being promptly returned almost as soon as it accumulates. On the other hand any tendency to back flow forcin water upwardly through the tube 26 operates both by impact and buoyance of float 25 to close the valve 2! instantaneously and as soon as thepressure in the boiler drops, the valve opens and releases the condensate, returning it to the boiler. The concave underside of the valve at 24 has an important function in assisting in the closing of the valve due to impact of water as by huddling.

Fluctuations of radiator and boiler temperatures producing periodic recession of boiler temperature cause corresponding recessions of pressure with sub-atmospheric or equivalent low pressures in the boiler otherwise referred to as vacua, which by reducing the pressure in the pipe I5 tends to lower'the level of the water innthe chamber 20, where air is frequently trapped to levels below that existing at the time in the boiler such subwater levels in the float chamber may be referred to as false water levels in the float chamber. These levels are slightly below the existing water level in the boiler and tend to slightly lower the feed valve control float 29 holding the valve 3? in open position and causing floodingof the boiler and filling of the steam space with water which also enters the radiators. This is the most frequent cause of ineffectiveness or inop-.

erativeness of the apparatus as previously applied to feed water controLsuch systems having been on the market with some variations for a considerable period.

In the present control this difficulty has been completely overcome by the use of a balanced or equivalent type air valve which opens freely to admit air to the boiler in response to subatmospheric pressures in the boiler or equivalent pressures if pressures of steam and air are employed which are more widely different from existing atmospheric pressures than those discussed.

This air release valve or vacuum breaking valve in the form ofsystem which has been tested and disclosed herein as an embodiment of the present invention, is directly connected to the steam space of the boiler by means of a pipe 19, being located in a chamber 60 in casing 9, and suitably balanced to open and admit air freely to the steam space whenever the pressure in the boiler recedes to the predetermined degree below normal, in this instance below atmosphere. To this end the weight 16 which is used to balance the valve and normally to hold it in closing relation to the seat, may be adjustable along lever arm 12 to give the desired spread, usually very slight between atmospheric pressure and the pressure at Which the valve opens. This determines the degree of vacuum which may exist in the boiler. Whenever the boiler pressure recedes below atmospheric pressure or other air pressures employed the valve being open beneath at 88 and concave to receive and impound steam a portion of the steam which tends to escape closes instantaneously due to impact and steam pressure and thus retains the full boiler pressure. However, whenever there is a vacuum or a drop below normal pressure in the boiler, the valve opens instantaneously till stopped by guides 79', providing a free flow of air into the boiler and thus equalizing the pressure in the boiler with that inthe chamber 20 and preventing false levels of the water in the float chamber, i. e., causing the float 29 to conform to the water level in the boiler and thus giving accurate regulation to the feed at all times and particularly preventing flooding of the boiler and the radiators.

The successful automatic control of the boiler feed in this type of system is regarded to an important accomplishment various apparatus for this purpose having been on the market but having proven almost wholly ineffective to accomplish continuously automatic control.

In the more limited view of the invention, the arrangement as well as the various valve assemblies and the combination of the same with a steam boiler system are regarded as new and constituting important contributions to the results obtained.

The apparatus, Figures 8 to 10, has the condensate return valve operated independently of the automatic control of this feeding of water to the boiler. Its construction and operation are believed to be clear from the description of these figures taken with the preamble to the specification and the description of the operation of the first form of the invention,

I have thus described a steam heating system and a feed water and condensate return control for the same, the system and control as described embodying features of the invention in what is now regarded as the preferredform, the description being specific and in detail in order that the manner of constructing, applying, operating and using the invention may be fully understood; however, the specific terms herein are used descriptively rather than in a limiting sense, the scope of the invention being defined in the claims.

What I claim as new and desire to secure by Letters Patent is:

1. The combination in a heating system having a steam boiler and steam radiators above the boiler, of a float controlled feed water valve, a feed water pipe leading from a source of supply to the boiler and controlled by said valve, a float chamber at the normal surface level of the water in the boiler, a float in said chamber controlling said valve which is connected to said float, a condensate return leading to said chamber which is connected to the water space of the boiler and a condensate return control valve in said return and a float operatively connected to said latter valve and also located in'said chamber, the rising of the Water level in said chamber, abovev normal serving to close both said valves and the falling of the water level below normal serving to open said valves.

2. The combination in a heating system having a steam boiler and steam radiators above the boiler of a float controlled feed water valve having a float chamber at the normal water level of the water in the boiler, a float in said chamber controlling said valve a condensate return leading to said chamber which is connected to the water space of the boiler and a condensate return control valve in said return and a float operatively connected to said latter valve and also located in said chamber, the feed water valve float being of annular shape with a central vertical opening and the condensate return control valve float being located in said opening and spaced inwardly from the wall of said opening to provide for the passage of the returning condensate through to said opening.

3. The combination in a heating system having a steam boiler and steam radiators above the boiler of a float controlled feed water valve having a float chamber at the normal level of the water in the boiler, a float in said chamber controlling said valve, a condensate return leading to said chamber which is connected to the water space of the boiler and a condensate return control valve in said return and a float operatively connected to sai l latter valve and also located in said chamber, the feed water valve float being of annular shape with a central vertical opening and the condensate return control valve float being located in said opening and spaced inwardly from the wall of said opening to provide for the passage of the returning condensate through to said opening, and means for diverting the condensate return directing it into said opening and preventing it from contacting the top surface of the feed water valve float.

4. A condensate return valve assembly for a steam heating system having a boiler means for maintaining said boiler pressure near that of the atmosphere, said system having radiators above the boiler and a condensate return pipe leading downwardly from the radiators, said assembly comprising a valve chamber having a downwardly disposed seat and a valve member having an upwardly disposed seating surface, a float cham' ber connected to said valve chamber, said valve chamber and said float chamber being adapted to be located in said return pipe which connects the float chamber to the boiler at a point beneath the water level, a float in said chamber connected to said valve to raise it into closed relation to the seat when the water level rises above normal and a vacuum breaking valve connected to the steam space of said boiler, and opening inwardly to introduce air into said boiler and into said system when the water pressure drops below normal.

5. A condensate return valve and feed water control assembly for a steam heating system comprising a float chamber, a feed water valve chamber and a cooperating valve and seat there? in, a feed water pipe leading to said seat, a feed water valve float of annular shape having a central opening means connecting the feed valve float to the feed valve to close the lattei'ift when the water level rises above normal and to; below normal,

open it when the water level drops I said float chamber being adapted to be connected member having an upwardly disposed seating surface the valve chamber surrounding said con,-

densate return valve member and seat, said chamber having a downwardly disposed tube ex: tending into the opening in said annular float and said condensate return valve having a float extending downwardly into said tube, said tube serving as a guide for said valve by contact of said float therewith, and passage means connecting said chamber to the boiler below the water level therein.

6. The combination with a steam boiler and radiators of a float operated feed-water valve, a pipe leading from a source of water supply to the water space of said boiler, a float chamber connected to said water space and located at the Water level, a float therein, said valve controlling the passage of water through said pipe, and means connecting said float to said valve to close the same when the water level goes above normal and also when the water level recedes to a pie-determined level below said normal, the valve being open at intermediate levels between said upper and lower level, means for controlling the pressure in the boiler to remain in the vicinity of atmospheric pressure and a vacuum breaking valve connected to the steam space of said boiler to prevent the establishment of a vacuum in said boiler, and hence to control the water level in the chamber to correspond to the water level in the boiler.

THOMAS W. H. ABBOTT.

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