US2312191A - Steam heating system - Google Patents

Description

Feb, 23, 1943- J. T. READER 2,312,191 I 'STEAM HEATING SYS':."1'}1\1l Filed OC). 14, 1940 2 SheS-Sheet 1 ATToR f n l V feb 23, 1943' J. TQREADER. 2,312,191

I STEAM HEATING SYSTE.M

Filed .0013. 14, 1940 2 Sheets-Sheet 2 INVENTOR 'ATToR 5.

the delivery' of Steam Patentedv Feb. 23, 1943 orties;

STEAM HEATING SYSTEM Joseph T. Reader, Grosse Pointe,

to synchronised Systems Company, a ship composed of Joseph 'l'. Machrls, Harold E. Rose,

Robert P, Butler Mich., assignorl partnerlteader, Charles E. Albert E. Fisher, and

vApplication october 14, 1940, Senn No. 361,013

12 Claims.

This invention relates to steam heating systems -for buildings andhas for its principal object the provision of a steam heating system of improved characteristics in operation and control and which will eil'ect economies in operation.

Objects 'of the invention include the provision of a steam heating system provided with pumping means at the outlet end of the system for purging the system of non-condensable gases and water of Y condensation together with means ,for controlling the flow constructed and arranged as to tend to reduce vinto the system as each' cycle of voperation of the pumping means is initiated; the provision of a Steam heating system having pumping means at the outlet end 'of the system for purging the Same of air, non-condensable gases and water of condensation cyclicallyoperated in accordance of the system, and a pressure reducing valve for controlling the ilow of higher pressure steam into the inlet end of the system, together with control means for'the pressure-reducing valve so constructed and ,arranged `that at the beginning of each cycle of operation of the pumping means; the pressure reducing valve will te'nd to close and reduce the supply of steam to the system whereby to enable the pumping means to quickly purge the system of the air, non-condensable gases and water of condensation; and the pro vision of a steam scribed in which initial reduction of pressure in the system at the outlet end thereof upon the initiation ofeach cycle of operation of the pumping means is eiiective to 4cause an .initial closing movement of the trolling the admission of steam to the'system and until the operating pressures throughout the system have reached an approximate state oi equilibri-um.

Other objects .of the invention include the provision of a steam heating system for buildings or the like so constructed the system is automatically re- .duced as the pressure in the system is reduced; the provision 'of a steam heating system in which the pressure existing at. the outlet end of the of steam into the System, sov

with the demands heating system of the class depressure diierencea thereby increasing the ef-v fective life of the steam traps.

A' inlet end of the system steam heating system including a. valve for introducing steam in'to the system. and a vacuum pump at'the discharge 'end of the system for maintaining the system under a predetermined degree of vacuum, sp'onsive to the pressure in the system at the discharge end and at the inlet end thereof serving to controlv the steam admittance valve but is so constructed and arranged as to decrease the differential of pressureibetween the inlet and outlet sides of the system as the degree of vacuum on the outlet end of the system is increased: and the provision of a steam heating system including control means therefor so constructed and arranged as to relieve steam traps or lthe like employed in the system of excessive Further objects of vthe invention include the provision of a steam heating system for buildings or the like in which a|` valve is provided at the for admitting steam from a Source of Supply thereto, and a. vacuum pump is .provided at the discharge end of the system for mamtaining the system under a desireddegree of vacuum, means being PIOvided `for controlling the valve comprising pressure responsive means including a movable wall connected to the valve and having one side thereof exposed to the effects o! the pressure at the inlet end of the system and the opposite Side thereof exposed to the effects of the pressure o! the system at the outlet end thereof, whereby it tends to maintain the differential of'pressure in the system conpressure reducing valve con` h and-arranged thatthe --diiferential of pressure between the inlet and -outlet Sides of stent, together with means for varying the effect of said pressure responsive means on said valve comprising an additional pressure responsive element including a movable wall subject to the pressure of the system at the' outlet end thereof on one face thereof and to the atmosphere or other source of xed pressure on the opposite face thereof and so constructed and connected to the valve as to vary the eilects of the ilrst mentioned movable wall to decrease the difierential between the inlet and outlet ends of the system as the degree of vacuum on the outlet end thereof is increased: and the provision of a construction as above described in which the change relative areas of the two pressure responsive ele'- ments may be changed to enable the rate of oi the pressure differential of the' system between maximum and minimum values to be varied to meet the requirements of the rnaximum and minimum pressure differentials required inthe system.

together with means :re-l

of the type described in which means are provided for shutting on' the supply of steam to the system whenever the primary pressure responsive element is ruptured to Ysuch an extent as to prevent yits functioning; the provision of a steam heating system of the type described employing a pair of pressure responsive'elements for controlling the pressure reducing valve so constructed and arranged that the introduction of steam to the system at excessive pressures will automatically cause the pressure reducing valve to be closed, thereby to shut oi the iiow of steam to the system; and the provision of safety means in a structure of the type described which will automatically prevent undesirable `high steam pressures to be built up in the system.

The above being among the objects of the present inventionthe same consists in certain novel features of construction and combinations of parts to be hereinafter described with reference to the accompanying drawings, and then claimed, having the 'above and other objects in view.

Fig. 1 is a more or less diagrammatic, frag-4 In the accompanying drawings which illustrate A type of steam heating system of the vacuum type that has recently met with a considerable amount of success includes a pressure reducing valve at the inlet side of the system to the stem of which is connected a diaphragm enclosed in a casing forming a chamber at each side of the diaphragm. The chamber on one sideof the -mentary view of a steam heating system constructed in accordance with the present invention;

Fig. 2 is an enlarged, transverse sectional view taken centrally through'the steam control valve mechanism shown in Fig. l;

Fig. 3 is an enlargedvfragmentary, vertical sectional view taken centrally through a modiiled diaphragm construction which may be employed in place of the diaphragmconstruction shown in Fig. 2, to obtain the same result; and,

Fig. 4 is a view similar to Fig. 2 but illustrating i a modified form of construction. The present invention relates to those types of steam heating systems for buildings or the like in which steam from a suitable scurce of supply is passed through a pressure reducing valve into the heating main at the inlet side of the system, and in which suitable pumping means are provided at theoutlet end of the system for removing the air and non-condensed vapors,

gases and water of condensation from the system, as well'as to maintain the outlet side of the system under pressures of suitably low value.

Although it is possible to use the present inven-` tion in connection with systems maintained wholly or partly-at or above atmospheric pressures, it will usually be employed in conjunction with so-called vacuum systems in which the outlet side of the system in particular is maintained under a partial vacuum or sub-atmospheric pressure, as these systems are capable' ofemploying exhaust gases from steam operated turbines, en-

gines or the like and in any event, regardless of y the source, are generally recognized as more ef' ficient and ,economical in operation than other types of heating systems. Accordingly, while for the purpose of brevity'in description the dis-Y cussion of the' present invention will be limited to its application to the vacuum type of systemj' its application to other .t'ypes f systems will bereadily recognized by those skilled inthe art upon' the disclosure herein without the .necessity of further explanation o1'- vthe present invention thereto. A

diaphragm is connected to the steam main of the system immediately adjacent the point at which the reducing valve introduces steam thereinto, suchchamber being the' one in which the presence of a vacuum therein, if the opposite face of the diaphragm were subjected to atmospheric pressure, would tend to open the valve. The opposite chamber, that is the chamber on the opposite side of the diaphragm is connected to the discharge side of the system and preferably to the vacuum return line thereof directly connected-to the vacuum or other pressure reducing pumping means positioned at that point. It will be appreciated that the resuitfof thisconstiuiztion is the provision of an automatically operated pressure reducing valve controlling the admittance of steam to the system and serving to maintain a constant differential of pressure between the inlet and outlet sides of the system regardless of variations of pressure at the outlet side of the system. The amount of dierential pressure maintained between the inlet and outlet side of the system is controlled by means of springs, weights or the like `constantly acting 'on the valve, through the diaphragm or otherwise, tending to move the valve either towards closed or open position and usually towards open position.

The above described heating system was a material improvement in theart for the reason that the engineer or other operator of the system could vary the flow oi.' steam through the system to accommodate thevarious heating requirements by simply varying the degree of vacu` 'In other words, the engineer could adjust the vaccum pump to produce a lesser degreeof vacuum and the pressure reducing valve a greater degree of diil'erential when the heating requirelments of the system increased, and 'adjust 'the vacuum pump to provide a greater degree of vacuum -and the pressure reducing valve a lesser degree of differential when the heating requirements of the system decreased. However, when the vacuum pump is operating after starting up automatically, the constant diiferential reducing pressure valve remains open and admits excess steam to the inlet side of the system because, `as the vacuum increases on` the lower side of the diaphragm, whichv is connected to the return end ofthe system, the vacuum onV the upper side of the diaphragm which is connected to the inlet side of the system increases correspondingly and the opening through the valve `tends to remain unchanged. 'I'he supply pressure to this valve is, of course, not changed '..n any respect'because of the operation of the vacuum pump, the pressure at the down-stream A side of the valve is reduced by operation of the ating lunder this l As readily understood inthe art, the higher -Y pump and consequently a greater amount of steam flows to the system when the pump is opermethod of operation.

- the absolute pressurein a heating's'ystem oi the type described the greateris the pressure diifer- 'loss due to steam -ential of ential required between `the inlet and outlet sides of the system to obtain the proper flow of steam through the system to obtain uniform heating flowing through the system. The greater degree v ythe differential of pressure vas the absolute -pressure in the systemis lowered has already been recognized, and one 'result is shown 1n United states Letters Patent of vacuum on the steam .in the system, the less pressure differential is required to cause the proper flow thereof throughv the system. because the quantity and specific gravity of the steam flowing is less and the drop in pressure required for a proper flow is less because of the smaller frictional losses. Accordingly, with the system described, conventional practice is to adjust the pressure reducingl valve, vas lby shifting of theweight orweights thereon, varying the tension -of the spring or springs thereof, or otherwise, so as to obtain the desired differential of pressure between the inlet and outlet sides of the system under conditions of-maxlmum heating requirements. If, under such conditions, minimum heating requirements are attained, the same differential of pressure between the inlet and. outlet sides of the system still-remains unless the operator adjusts the pressure reducing valve itself. as by shifting the weight thereon or by varying the tension of thesprings thereof, to reduce the differentialgof pressure as controlled thereby.

or lesser extent, or by shifting the weight or the springs which load the pressure reducing valve associated therewith, the differences in pressure thus set up between the inlet and outlet sides of the system being utilized to control the operation Unless such differential of pressure is adjusted some/material disadvantages 'resultjunless the system and particularly the r'adiatoriand drip traps thereof are [inI substantially perfect condition.` In other words, by maintaining a constant differential between the inlet'and outlet sides ofthe system when such differential is not required tocause a proper'flow'of steam through the systems under low absolute pressure conditions,'the differential of pressure on-the opposite side of the thermostatic traps on the radiators comes excessive and cause these traps to close more tightly to 'maintain this excess difference f 'in pressure. Naturally, thse traps'located closs est to the source of heat supply, where the friction travelling through the pipes-is very little, will have to maintain a greater ydifferkrressure than those located 'at the far end of th short circuiting from the steam supply to the vacuum pump, causes a waste of steam through this by-passing, and this/steam in turn tends tol lessen or destroy the vacuum carried inthe system. The circulation to the furtherest radiators then becomes sluggish or ceases entirely and uneven and wasteful heating results. In addition, all of the traps in the system must remain closed'v during the greatest part of the time `or this excess Y and on the opposite sides of the driptrapsbescribed an additional pressure operated subject to a substantially xed pressure, and which differential could not be`- maintained, and this makes itdimcult for the condensation, air and non-condensable gases to be eliminatedy from the radiators, aggravatingthe unsatisfactory condition still more. Accordingly, it will be appreciated that unless the pressure differential existing between the inlet and outlet sides of the system is reduced as the vabsolute pressure in the system is reduced, conditions arise kwhich prohibit the most advantageous operation of the system to 'be realized.

'Thedesirability of providing a vacuum heating of the vacuum pump to produce a corresponding,

greater or lesser Vdegree of vacuum at .the outlet vend of the system.

The results sought to be attained by the Jenning'spatent can, by the practices of the present invention, be obtained in a simpler, quicker and more economical v.manner modification in the construction of the fixed differential system first described and by ing variations in the absolute pressure of the system at the discharge end thereoftc control the admittance of steam to the system, rather than by varying the admittance of steam to the system to control the degree of vacuum in the system as in Jennings.l Additionally, it is to be noted that' a system constructed in accordance .with the present invention has an inherent advantage over'the Jennings system in that in the' system of the present invention each time a cycle Jennings system an accelerated flow fof steam results under the same conditions with all of the attendant disadvantages. Briefly, this is accomplished by adding to a pressure reducing lvalve of the'xed differential type previously deelement `may, therefore, be atmosphericpressure, on .one

side. and to the pressure at the outlet end of the system on its other side, and utilizing the movement of or effective force on such pressure operated element to vary the effects of the main diaphragm on the pressure reducing valve. In other words, this second mentioned pressure operated element connected to the outlet end of the system on one side and to the atm'osere on the other side-will produce a force varying in proportion to the variations in pressure at the out- -letend ofthe system,

and if this force is added tothe force set up on the corresponding side of the diaphragm of the conventional fixed differential pressure reducing valve. as by being directly connected to such diaphragm or to the stem of'the valve, or by varying the tension of the spring or weight which loads the valve, then the pressure reducing v alve instead of 'maintaining a constant differential of pressures between the inlet and outlet sides of the system will maintain a pressure differential which will decrease as the absolutev pressure at the outlet side of the system having means for automatically reducing system decreases.

Thus in accordance with the present invention itis possible by simply controlling the vacuum' pump to degree of v vacuum at the outlet end of the sysmeans of accomplishing the No. 1,851,434, issued March 29, 1932 to I. C. Jenby a relativelysimple employproduce a desired system. v Y

tem, to control the amount o'risteamfnowing fth'rough the system, as-wellla's theeilective head and particularly to Fig. 1 which'fillustrates a typical system embodying the present invention, 'the numeral rI8 indicates' generally a suitable steam boiler of any approved type which discharges steam therefrom-into a steam main I2.

- or diierential of pressure on-v such steam `which Jcauses the ilow thereof through the system. .Referring now to the accompanying drawings Vcomxnerciai type thermostats located so that they would be' affected-by outside temperatures, could -each be connected to a suitable vacuum operated regulator for-the motor'84, and each thermostat adjusted so that its corresponding regulator would make lcontact at a diilerent temperature than the rest, and the corresponding regulator serve to. eifect operation, of the motor 84 to maintain a degree of vacuum in the system lcommensurate provided "with .additional branchesA 2'8 to each of which one or more heat diiusing media', which may be oi.' any suitable or conventional type, but

for the purpose of simplicity in description and.

drawing are here shown as radiatorsl 22, are connected by means ot pipes 24. The term radi- 'atorwhen used in the claims is to be interpreted to mean any suitable or conventional heat diilusing media.. 'Ihe outlet sides of the radiators 22 are connected by pipes 28 to a vacuum return line 28, a thermostatic trap 88 being provided in each of the pipes 28 at the outlet side of each radiator in accordance with conventional practice. The lower ends of the branches 28, which extend below the corresponding radiators 22, as -well as other low 4points in the system,

' are also connected to the vacuum return line 28 by means oi' pipes 82 in which some suitable type of 'sealing means are preferably located. Buch sealing means may. take any usualor desirable 'form such as a water leg, orince, trap or the like but-for the purpose of illustration are shown as traps 84.

The vacuum return line 28 discharges into a receiver 48 in which the condensed steam is sep- 'arated from the non-condensable gases and vapors, suchcondensed'steam being'drawn out of Y the receiverand returned to the boiler by means r of a pump 42 and pipe line 44, the pump 42 be- -lng driven by a motor `48 o! a iloat controlled type conventionally employed in the art for this purpose. The receiver 48 is connected by a pipe line 38 with a vacuum pump 82 which discharges into a separator 88. The pump 82 maybe driven in any suitable manner as, tor instance, by a steam or other engine, steam turbine, Aelectric motor or the like, an electric motor 84 being shown by way oi' illustration.

Operation of the motor 84 eectsfoperation of the vacuum pump 82 which in turn places the interior of the receiver 48 -and consequently the vacuum return line 28 under a partial vacuum, the condensed steamflowing into the receiver trom the-vacuum return line 28 being separated out in the receiver and returned tothe `boiler in accordance with conventional practice.'4 The vacuum pump 82 may be controlled in any suitable wa'y, that is, by-operating the'motor 84 continuously or intermittently, and wherev continuously it may, i! desired', be accomplished by suitably varying the speed of the motor or other prime mover 84 and consequently the pump '82 to obtain the desired degree of vacuum in the The motor 84, and consequently the pump 82, may be automatically controlled in accordance with the demands on the system as based Aon out- :ide temperatures. For. instance, a'plnrality of lcap 82 carryinga which is ilxed a two-part housing 88 centrally di.'

pump 82. 1 In order to variably control the iiow of steam into the main I2 from the boiler I8 a pressure re able or conventional manner with the heating requirements based on the then However, a simpier method, although not automatic, is'shown existing outside temperature.

in the drawings by way of illustration and com- 'fprises a' control panel 88 having three control buttons 88, 88 and 82, respectively, thereon. 'I'he control Ibuttons 88 and 82 are each associated matically cause operation of the motor 54 to maintain a substantially lconstant and respective- -ly-predetermined suction pressure inthe vacuum return line 28. As a matter of illustration it may .be assumed that when the button 88 is operated the motor 84 will be controlled to maintain the vacuum return line 28 under a suction pressure oi.' twenty inches of mercury and when the but- `ton 82 is operated to control the motor 84 the vacuum return line 28 will be maintained under a suction pressure of ni'teen inches of mercury.`

The button 88 may be assumed to operate to control continuous operation of the motor 84 and ducing valveindicated generally at 10 is interposed in the main I2 adjacent the valve I4 but on the down-stream side-thereof. While any suitable type of pressure reducing valve may be .employed for this purpose, one conventional -type of valve is shown in detail in Fig. 2 by way vof illustration and referring to such figure it will -be noted that it comprises a casing or housing having an inlet 12 and an outlet 14, together with a pair of ports 18 connecting the inlet and outlet. 'I'he ports .18 are each formed to provide a valve seat at their upper edges with each of which 'a valve 18 isarranged in cooperating relationship.l The valves 18 are rigidly connected together by means of a post 88, the construction thus providing a balanced valve -of a conventional .type familiar to those skilled in the ar l The lowerface of thevalve 10 is `closed Vby a post 84 to the lower end of vided Iby a ilexible 'diaphragm 88 sealedA at its margins thereto and forming cham-bers 88 and 82 interiorly oi' the casing 88. A stem 84 fixed at one end to the valve assembly, includingthe valves 18 and post 88, concentrically therewith extends downwardly through ythe post 8| and into the casing 88 where it is fixed to the center 'oi' the diaphragm 88,- a suitable packing indicated generally at 88 serving to seal the stem 84 in its passage through the post 84. This assembly may be loaded towards open valve position in any suitas, for instance, by

springs, weights, or the like. vWeights are shown .by way of illustration and arranged ina conventional manner. To' accomplish this the lower face oi the casing 88 is provided witha.boss-88 there- 258123159l g y onfinxwhich ,the stem '88 is also;suitellbly-v sealedand-theboss-is providedgwlth an offset arm` the link |02 is pivotally -to which one end of connected. The opposite endof the link |02 is pivotally-:connected to a bar |04 to which the lower endof the stemv'84-is also pivotally connected as at |08. Onthe oppositeside of the pivot |08 thewboss198is provided with a rigid Toovercome these diiliculties the operator should adiustthe weight |2 onthe rod |04, or such other means as isemployed to load the reducing valve, to reduce the diierential at 'whichthe f valve operates. In other words, whenever a change in the heating-requirements of the sysbifurcated 'armv |08 within which the bar |04 is guided for vertical movement. The bar |04 has a5 plurality of weights adjustably mounted thereon.

longitudinally thereof, the fweights ||0 ordinarily remaining xedonce the -system is adjusted and chamber -80 above the diaphragm 8 8 is connected by .a pipeline v-| |6 tothe main |2'at a point relatively' close to the valve 10.and'the chamber 82 below. the diaphragmf88isfconnected by a pipe linef`|-|8with the vacuum return line V28. A tank rims preferabiyinterpcsed in .both lines' Ils and |18; end these tanks become filled with condensed steam providing a constant head of water on the opposite sides of the diaphragm 88so as to elimiferring now to Fig. l'it willbe' noted that the'.

nate Vpossible variations in the control due to l variations in theamountspf condensedl steam which might otherwise act -on the opposite sides of the diaphragm.

The .construction thus far jdesc-rated is the con-f vfii'tinal fixed differential type of system previously discussed, the construction and arrangement of'the` valve 10 and the control therefor serving, tomaintain a, constant ldiierential of;l

pressure between main` I2 on the outlet side or th' valve 10 and the'va'cuum return line 28, the amount ofsteam passingthrough the system and consequently the heating effect of the system varying inversely with the degree of vacuum in the 'return line 28. For instance, if it is ascertained 'that the maximum pressure drop through thesystem to the most remote radiator in subzero. weather is','as a matter of illustration, three pounds or slx'inches of mercury, and, if steam at a'tem'perat'ure. corresponding toone pound E aug'epressure is required to heat the building, under'the'se conditions, then with one pound g'aug'e steam pressure vand the differential valve properly 'adjusted the vacuu'n in the return line tem is necessary, two-adjustments must be made b y the operator if proper operating conditions are to result. Thefirst oi these changes is a change in -the degree ofvacuum in the return line 2 8 as controlled by the vacuum pump 52, and the second is a change in the differential required to actuate the valve I0 as controlledby the position of the weights on the rod |04. A As a matter of fact, however, most operators fail or neglect to adjust the differential of the reducing valve and for that reason such systems operate at maximum eiliciency only during coldest weather.

The diiiiculties inconnection with the heating system described above may be avoided by modifying the control for the pressure reducing valve so that the pressure diierential maintained between the opposite ends of the system thereby will vary-in accordance with the variations oi.' absolute pressure at the discharge end of the system.

This, of course, may be accomplished by providing a pressure responsive `element responsive to vvariations in pressure, at the outlet end of the system and employing such elements to modify the action of the valve as controlled by the diaphragm 88. It may be accomplished by connecting the pressure responsive element to the movable element of the valve, orby employing it to change the load on the valve the same as would 'beaccomplished by shifting the'weights associated therewith where weights are used to prevload the valve, or by varying the tension of the spring where springs are employed to preload the valve. Such pressure responsive element, in 'order to be eective for the purpose described,

must, of course,` exert a force proportional to be subjected to such pressure variations on one side and to a substantially ilxedpressure' on the would be four inches of Imercury or thirteen pounds absolute. If, in moderate weather, the vacum'at'the pump was inches of mercury'orseven and one-half pounds absolute, then steamvwould'circulate if introduced into. the system'under a vacuum of nine increased to fifteen 'sired results. This is the construction illustrated incliesof mercury or approximately ten and onenalipounds absolute. If, in real .mild weather, al"'acu11m of twenty inches of mercury orfive peunds' absolute was carried in'the return line', their the Asteam `would circulate'at avacuum equal toffourteenY inches of mercury or appro'ximately eightpounds absolute. `I'Iowevelf'. due to the less quentitlinesl of steamlreduired by' systemunderl the'latter two condition's','the pressureldrop, due" tofiictio in the systexlfb'e'comes less andjexcess f differential ,lens1 1"e"s This canonl'ybe caused by thel radiator and drip traps" closing during the majorltylof the time to maintain this excess differential andjvhlqh they will notdo-.if in worn condition. Under these conditions, causes 'short circuitingof y l 0 tiabsilhi herretu'rn temperature, loss o! 'vacfliltr circeletee. and www 01 .Steria 'exceesdifferentialthestean'rthrol'lgh the f otherv side. 'While .such 'ilxed pressure may Abe obtained from any suitablesource, atmospheric pressure will be the simplest and most economical to employ as will be readilyappreciated.

A diaphragm such as the diaphragm, 88 andan associated casing is perhaps the simplest form of pressure responsive element for eiecting this pur.. poseand maybe. directly connected to the movable element of the valve to`l accomplish the dein Figs. 1 and 2 and referringparticularly to Fig. 2 isl accomplished as follows. A diaphragm casing indicated generally at |'is mounted below the casing 88 in downwardlyspaced relationwith revspect thereto by means of legs |82.` 'I'he' casing |80 is of the same lgeneral, construction as the' casing 88 and is lnteriorlyprovided with a diaphragm |84l which divides the interior thereof Linto a. lower chamber |38 and anfupper chamber |88. A stem |40seeure'd to the diaphragm |84 extends upWa-rdlythrou'gh the casing |80 and at.

its upper end is 'suitably' connected to the'- stem '04 by the same pivot pin |08 which connects .thestem 04--to'the rod |04. Consequentlyfthe diaphragms 88 and |84 are connected together' for equal movement. YThe upper halfof the cain g |38 is provided with an opening v|42 therein connecting consequently will exert a torce on the stem M and consequently on'the valveassembly ll-80 which at all times is proportional to the pressure in the outlet end of the system. This force is in addi- `tion to the equivalent i'orce which will be exerted on the lower face of the diaphragm 8l but which in the case of the diaphragm I8 is oiset by the varying pressure in the chamber 8l and which pressure acts onits upper face. The' result is that as the pressure in the outlet end of the system decreases the relative diierences in pressures act- `ing on the opposite i'aces of the dlaphragms Il and |31 tending to move the valve 'iii towards closed position increases and as the pressures in the outlet end of the system increase .the relative difference in pressures acting on the diaphragms 88 and III tending to-close the valve decrease, thus providing for a greater 'diii'erential between the inlet and the outlet end of the system. Obviously by varying the enective diameter oi' the diaphragm i the force eirerted through the diaphragm |34 tendingato change the diiierential ascontrolled by the diaphragm 8i may be varied so that the actual differential of pressures acting' through the diaphragms to control the valve at various pressures in the outlet end ci the system may be varied as desired to meet any condition en' countered in service. Atthe same time, adjust- A ment of the weights vIll and H2 on the rod I permits a desired ditl'erential between the inlet and outlet ends oi the system to be provided for g at any-particular operating pressure o! the system.

l It will be appreciated from the above description that in a steam heating system constructed in accordance with the present invention the amount of steamri'iowing through a system may be controlled by simply varying vthe operation ci the vacuum pump l2 to produce any desired degree of vacuum in the return line or the'system,- and that any variation in the vacuum in the return line will automatically operate to establish a correspondingly desired diiiferential o! pressure between the inlet and outlet ends of the system and that such diiierential of pressure will increase with the increase in absolute pressure in the return line and will decrease with decrease in absolute pressure in the return line. It will also be appreciated that where the control valve is properly constructed and adjusted it will automatically operate to establish that differential of pressure between the outlet and inlet ends of the system most favorable for optimum operating conditionsfor any normal operating pressure that is selected for the outlet end ot the system either by the operator or by automatic devices. It will also be appreciated that the added expense required to obtain this advantageous condition oi' operationy is substantially negligible.l

One extremely benencial eiiect of the above described construction is as follows. With an ordinary pressure reducing valve in a system of the type described, the moment operation of the vacuum pump is initiated, the differential begween the outlet and the inlet is increased with the t that excess amounts of steam are admitted to the system. The admission oi this additional steam to the'syatem makes it more diiiicult for the vacuum pump to remove the air. non-condensabie with the pipe line ill and consequently to thel gases and condensed water fromthe-system and requires a much longer operation of the vacuum pump to reduce the vacuum to the desired deree.

With the valve construction employed in con-v junction with the present invention each time a cycle of operation of the vacuum pump l! is initiated the reduced vacuum is iirst apparent in the outlet side of the system and is immediately lmade apparent on theunderside of the diaphragms, thus tending to close the pressure reducing valve and reducing the amount of steam that is admitted to the system. It will be appreciated, of course, that the corresponding reduction of pressure in the outlet end of the system will shortly be apparent at the inlet'end of the system but, because of the addition of the lower diaphragm i, a proportionally greater pull will be exerted on the diapIuagm-tending to close the valve than would be the case with a conventional type of control. The result of this construction The above described advantage is not` only important from the standpoint ofmore quickly purging the system of air, non-condensable gases and condensed water with consequent shortening oi the operating period of the pump and its operating motor but it also is eiiective in reducing the peak load of steam used by the system. In this connection those skilled in the art lwill understand that where steam is purchased from a cen. trai heating company on a demand basis, the custemer. in addition to a fiat rate for all steam consumed during the year, is also charged an extra demand rate. This demand rate is determined ordinarily by the averaging of the several largest hourly rates of steam consumption during certain periods of the heating season. It these maximum hourly peaks can be reduced, very considerable savings are eii'ected. By reducing the quantity of steam admitted tothe system each time operation of the vacuum pump is initiated, the high rate of steam iiow inherent in the usual types of pressure reduction valves under such of the system nor aliecting the ben'eiicial resulte labove described, is that it admirably lends itself to the provision ot a safety means for the system. In the use of conventional pressure reducing valves employing a diaphragm or o er similar pressure responsive element. shoul the Adiaphragml become ruptured, as is notvluncommon.`

pressures onopposite sides of the diaphragm or other pressure responsive elment are equalixed and the valve consequently moves to open position showing the full pressure ai. the steam supply -main orv other source ot steam to be applied directly tothe entire heating system. This does no particular harm where the supply of steam is under relatively low pressure except to increase .the temperature oi the heated space to an exec sive extent, vbut where the supply of steam is unof which is subjected to the pressure at the inletv der a relatively high pressure, for instance 100 g the larger of which` is pounds per square inch or greater, dangerous conditions arise, for instance, because of the high temperatures to which the various parts of the heating system may be broughtA to and possible rupture of weakened portions of the same. Such possibilities may be automatically avoided by a simple expedient inthe use of the valve above described in connection with the present invention. This isaccomplished by providing a pipe line such as between the steam main |2, on the downstream side of and preferably adjacent the valve'10 and the interior of the casing |80 above the diaphragm |84, and providing a pressure responsive valve indicated generally at |12 in the pipe line |10 so constructed and arranged that it will open to vpermit the passage of steam through it only upon the presence of a predeter` mined pressure of steam in the supply line |20.. f

While any suitable type of pressure responsive valve may be employed for this purpose, that shown in Figs. 1 and 2,'and in detail in the latter view,.by way lof illustration consists of a casing |14 having an inlet at one end andan outlet at the other end with a valve seat |18 interposed therebetween. A valve |18 is arranged in cooperating relationship with respectto the seat |18 and is constantly urged towards seated position by means of a coil spring |80. The force of the spring |80 determines the pressure at which the valve |18 leaves the seat |18 to permit the flow of steam through the pipe line |10 tothe casing |80. For instance, where the maximum pressure to open at a gauge pressure of fifteen pounds per square inch. The capacity ofthe pipeline 10 is l made greater than the capacity of the vent opening |42 so that should the upper diaphragm 88 become ruptured and permit the pressure reducing valve to admit excessivequantities of steam to the heating system materially above the intended maximum pressure, as soon `as steam in the main I2 -on the discharge side of the valve 10 reaches the maximum force the valve |1213 designed to operate, in the example assumed fifteen pounds, the valve |18 will open and permit steam under this high pressure to flow into the upperpart of the casing |80. Because the vent opening- |42 is of less capacity than the pipe line |10, under such conditions a positive pressure willbe built up in the casing |80 above the diaphragm |84 and will act to' move the pressure reducing valve 10 to closed position thereby to prevent further admission of steam to the system and preventing any condition from arising which would permit dangerous pressures to become apparent in the system. o-Where such saietydevice is employed it is preferable to connect the vent open-A ing |42 to some suitable pointof discharge as,

' for instance, the outside of the building, by means ofa pipe such as |82. l

' It-will be appreciated from the foregoing that the addition of the diaphragm |84 to the conve'n-y tional nxed diierential type of reducing valve in a steam heating system. has the effect of increas ing the area of the lowerface ofthe diaphragm 88 in the conventionalconstruction without in'4 creasing the area of the upper` face thereof, so

that differences inv. pressure at the outlet end oi!` the system willv have a greater effect on the con trol of. the valve than the same differences in pressure on the upper` face loi' the diaphragm. This suggests the possibility ofemploying al construction embodyin'stwo diaphragms the smallertl end of the system and subjected to the pressure at the outlet end of the system to obtain the same result. Such a'construction is illustrated in Fig. 3 wherein parts equivalent to the parts illustrated in Fig. 2 are indicated by the same numerals except that such numeral bears a prime mark. y

Referring to Fig.' 3 it will be` noted that. the diaphragm casing 86', similar to the diaphragm casing 88 previously described, is made in two parts but in this case the lower half of the casing is of greater diameter than the upper half. The two halves of the casing in this case are spaced from each other by means of a spacer having a stepped lower face. A diaphragm |82 is clamped and sealed between the spacer |80 and the upper half of the casing 88' and another diaphragm |84 is clamped and sealed betwe'n the lower face of' the spacerA |80 and the lower half a materially larger eiective area than the' diaphragm |82, for instance ltwice `as great. The stepped lower face of the spacer |80 permits the diaphragm |84 to be effective beyond the effecof the casing 88 is connected to the steam main |2 in the same manner as the chamber 90 previously described; and the chamber 92', corresponding to the chamber 92 previously described, is connected to the vacuum return line 28 of the system. The two diaphragms are rigidly connected together at their centers through the stem 94' of the valve so that' they are constrained to equal movement. As will be real-ized, with this constructionl the effective area of the diaphragm subject to the pressure at the outlet end of the system is greater than the effective area of the diaphragm subject to the pressure atlthe inlet'.

end of the system and consequently variations in pressure at the outlet end of the system will have a greater eiect'on controlling the position of the valve 18-80 than the, pressures at the inlet end of -the system, and as the degree of' -vacuum inthe chamber 92' increases, its relative effect on overcoming thev load of the weight ||2 will increase as compared to the relative increase of the partial vacuum in the chamber tending to add its eiiect to the load |2 and, consequently, the differential of pressuresas controlled by the valve 10 will be reduced; In other words. the same ultimate result is obtained by the construction shown in Fig. 3 as is obtained by the construction illustrated in Fig. 2.

'. As previously mentioned, the desired result may also be obtained by employing a pressure responsive element subject to the pressures at the outlet end of the system for varying the load proemployed for loading the valve. In Fig. 4 a. con- Istruction is illustrated in which this latter eiect is obtained. Referring to Fig. 4 it will be noted that the construction is identical .to that illustrated in Fig. 2 with the exception that the lower diaphragmlcasing |80 and its diaphragm is elimimounted on the rod |04 although the righthand weight H has been eliminated primarily for the purpose oi! clarincation. The weight il! has been replaced by a weight uz' of slightly different construction and readily slidable along the rod |04. In this case a metal bellows |00 has one end thereof rigidly secured' to a bracket |62 ilxed to therod |05 on the righthand side of the link 02 and the bellows extends in parallel relation to the rod |04. The opposite end of the bellows |80 is connected by a short rod |84 with the weight H2'. A coil spring |60 within the bellows |80 constantly urges the movable end of the bellows |00 to the right or outwardly of the rod |04 to thus position the weight H2 in a position to exert a maximum load on the valve 'll-80. The interior of the bellows |00 is confnected-by afiexible tube |68 with the chamber thus decreasing the effect or the weight uz' in loading the valve I0-480 and thus reduce the diilerential of pressures between the inlet and outlet ends of the system as controlled by the valve. As the pressure in the outlet end of the Vsystem increases, the pressure on the interior o! the bellows |00 will decrease thereby permitting the spring |60 to move the weight H2' outwardly away from its Iulcrum and increase the load on the valve so as to adjust it to maintain.

a greater diilerential .of pressures between the inlet and outlet ends oi the systems. 'Ihe ultimate eiect obtained is, o! course, equivalent to that obtained in the constructions illustrated in Figs. 2 and 3, the only difference being that the eiIectis obtained by a diiTerent means.

Formal changes may be made in the specifi-c embodiment of the invention described without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

What is claimed is:

1. In a steam heating system ofthe class including a steammain, a return line, a plurality of radiators connected between said main and said line-pumping means connected with the return line for removing air, non-condensable gases and water of condensation therefrom and a reducing valve for controlling the admission ot steam to the main, the combination with said reducing valve of loading means constantly urging said valve toward openv position, and

means for varying the effect of said loading means comprising a nrst chambermeanssubject to the pressure existing in said steam main and having a movable wall means so connected tosaid loading means as to oppose the effect oi' said loading means on said valve. and a second chamber means having movable wall means subject to the pressure existing in said return line and so connected to said loading means as to oppose the eiiect oi' the first mentioned movable wall on said loading means, the area oi the last mentionedI l l wail means exceeding the area of the tiret men- 7s' nated. The lefthand weight ||0 is shown tioned wall means whereby variations in pressureI in said return line have a greater iniluence in varying the eflect of said loading means on said valve than identical changes in pressure in said steam main.

l2. In a steam heating systemv of the class including a steam main, a return line, a plurality of radiators connected between said main and 1 said line, pumping means connected with the return line for removing non-condensable gases therefrom and a reducing valve for controlling the admission of steam to the main, the combination with said reducing valve of pressure responsive meansoperatively connected thereto,

said pressure responsive means including chamber means having movabley wall means subject to the pressure existing in the inlet end of the said system and tending to move said valve in one Y direction and chamber means having movable wall means subject to the pressure existing aty the outlet end of said system and tending to move said valve in the opposite direction, said movable wall means being so connected to said valve that the force resulting from the difference in pres- -sures acting on said movable wall means tends to close said valve. the area oi the last mentioned movable wall means beingin excess of the area oi' the ilrst mentioned wall means whereby the force exerted byngtheiast mentioned wall means tending to 4move ythe valve in one direction increases at a proportionally greater rate than thel force exerted by the first mentioned wall means opposing the force of the'second mentioned wall means as the absolute pressure in the outlet end -and pressure actuated means for moving saidl valve against the force of the last mentioned ,means said pressure actuated means includingmovable wall means connected to said valve and subjected to the pressure of said system in said Vmain tending to urge said valve in one direction and subject to the pressure existing in saidl re-v turn line tending to urge said valve in the opposite direction, the last mentioned means being so constructed and arranged as to ypresent a -greater area to the eilects of the pressure in said return line than to the eilects of the pressure in said steam main whereby to exert,a force on said valve varying with the -variations o! pressure in said system to aj greater degree than the force vexerted on said valve through variationsloi pressure in said steam main.

4. In a steam heating system of the' class including a steam main. a return line,- a plurality o! radiators connected between said main and said line. pumping means connected with the' return line for removing non-condensable gases therefrom and a reducing valve for controlling the admission ci' steam to the main, the combination with said reducing valve oi' loading means constantly urging said valve towards open position. a` diaphragm connected to said valve and' subject tol variation; in pressure in said steam main on one tace thereof and subject to `vitrintions in pressure in said return line on the oppo-l `site fece rfsticreoi, the connection between said l valve of'means connected thereto for controlling the operation thereof valve and diaphragm being such that the difference in pressure on opposite sides of said diaphragm opposes the eiects of ,said loading means and an additional diaphragm connected to said valve subject to variations in Vpressure in said return line onone face thereof and subject to a substantially constant pressure on the opposite face thereof for supplementing the eiects of the first mentioned diaphragm on said loading means. y

5.-In a steam heating system of the class including a steam main, a return line, a plurality of radiators connected between said main and said line, pumping means connected with the return line for removing non-condensable gases therefrom and a reducing valve. for controlling face thereof and acting in opposition to said rst diaphragm, the diierence in' forces acting'on said diaphragms opposing` the eiTect of said loading meansfon said valve, the effective area of said second diaphragm exceed-ing the effective area of said first diaphragm whereby the force exerted by said second diaphragm on said valve varies to a greater extent than the force exerted by said rst diaphragm on said valve upon equal lchanges in pressure at Opposite ends of said system. y

6. In a steam heating system of the class in-v cluding a steam main, a return line, a plurality of 'radiators connected between said main and said line, pumping means connected with the return line for removing non-condensable gases therefrom and a reducing valve for controlling the admission of steam to the main, the combination with said reducing valve of loading means constantly urging said valve towards open position, a diaphragm operatively connected to said valve and subject to the pressures existing in the steam main on oneface thereof and to the pressures existing in saidreturn line on the opposite face thereof, the connection between said valve and diaphragm being such thatA the difference in pressures acting on said diaphragm opposes the eiect of said. loading means on said valve, and an additional pressure responsive means subject to the pressure existing in said return line on one face thereof and to a substantially constant pressure on the opposite face thereof operatively connected to said loading means for varying the loading eiects thereof during variations of pressure in said return line whereby to feed greater Y the admission of steam to the mairnthe combi-` comprising movable wall means different areas of which are subject to the pressure in said main and return line, respectively, said movable wali means having a greater area thereof subjectedto the pressureof said return line than to the pressure of said steam main and being so constructed and arrangedwith respect to said reducing valve as to tend to close said valve upon increase in pressurein said steam main and diminution of line, whereby upon initiation operation of said pumping means said movable wall means tendsto close saidvalve.

8. In a steam heating system of the class including a steam main, a` return line, a plurality of-'radiators connected between said main and said line, pumping means connected with said return line for removing air and non-condensable y gases therefrom,

means for eilecting cyclic operation of said pumping means, 'and a reducing valve for controlling the admission of steam to the main, the combination with said reducing valve of means connected thereto for controlling the operation thereof comprising pressure responsive movable wall means subject to the pressure in said main and return line, respectively,

a greater area of said pressure responsive4 movable wall means being subjected to the pressure .of said return line than to the pressure of said steam main and that area of -said pressure responsive movable wall means subject to the pressure in said return line in excess of the area thereof subject to the pressure in said main being at least partially opposed by a substantially constant pressure, whereby a reduction in pressure in said system is accompanied by a greater force tending to move said valve towards closed position than the corresponding increase in force tending to move said valve towards open position 9. In a steam heating system of the class including a steam main, a return line, a plurality of radiators connected between said main and said line, a pressure reducing valve for controlling the admission of steam to the main, and a pressure responsive element subject to the pressure diierences between said steam main and said return line for controlling said Valve, the combination with said valve of means for closing the same upon the occurrence of conditions equalizing the pressures on opposite sides of said pressure responsive element comprising a second pressure responsive element connected to said valve, means connecting said steam main to one amounts of steam to .said system upon increase in absolute pressure in said system'and feed lesser amounts of -steam to said system with dccrease in absolute pressure in said system.'

7. In a steam heating system of the class inface of said second pressure responsive element, means for discharging steam from said second pressure responsive element at a lesser rate than that at which it may be delivered thereto from said steam main, and pressure responsive means normally closing communication through said connecting means operable to permit the flow of steam therethrough upon the presence of an abnormal positive pressure in said steam main.

10. In a steam heating system of the class including a steam main, a return line, a plurality of radiators connected between said main and said' line, a pressure reducing valve for controiling the admission of steam to the main. and a.

pressure responsive element subject to the pressure differences between said steam main and *said return line for controlling said valve, the

combination with said valve of means for closing the same upon the occurrence of conditions equalizing the pressures on opposite sides of said pressure responsive elementV comprising a. casing,

pressure in said returnv of each cyclev of f valve, said casing having a vent therein on one side of said diaphragm, means providing a passageway between said steam main and the vented side of said casing of greater capacity than said vent, and means associated with said passage normally'blocking the flow of steam therethrough but operable upon the presence of an abnormal pressure in said steam main to admit a ow of steam from said steam main to said second pressure responsive element whereby to eil'ect a closing movement of said valve.

11. `In a steam control valve comprising a casing forming a steam passage and a valve movably mounted therein for controlling the flow of steam therethrough, means for controlling the position of said valve comprising, in combination, a housing xed with respect to said casing, a diaphragm dividing said housing into a pair of chambers,

means sealing said chambers from the atmosphere and said chambers being respectivelyv formed for connection to the steam side and the return side of a. steam heating System, a second housing i'lxed With respect t0 said iirst housing, a diaphragm dividing said second housing into a pair of chambers, means connecting said diaphragms ior equal movement, said second hous ing being formed to connect one of said chambers l 2,312,191 a diaphragm in said casing connected to said with the return side of said steam heating system, means for connecting the other of said chambers of said second housing with the steam side of said steam heating system, a valve in said connection operable to admit steam to said last mentioned chamber only upon the presence of a predetermined maximum pressure in said connection, and means having a lesser flow capacity than said connection venting said last mentioned chamber to the atmosphere.

12. In a steam control valve comprising acas- 'ing forming a steam passage and a valve movably mounted therein for controlling the flow of steam therethrough, means for controlling the position of said valve comprising, in combination, a housing i'lxed with respect to said casing, a pair of diaphragms dividing said housing into three chambers, one of said diaphragrns being of greater diameter than the other thereof,means for venting the chamber formed between said diaphragms with the atmosphere, means for connecting the remaining chambers to the steam` side and the return side, respectively, of a steam heating system, means connecting said diaphragms for equal movement, and means con-V necting said diaphragms with said valve.

JOSEPH T. READER.

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