US2271778A - Controlled volume steam heating system - Google Patents

Description

Feb.v 3, 1942.

P. BQPARKS ETAL CONTROLLED VOLUME STEAM HATING SYSTEM Filed May 17', 1940 4 Sheets-Sheet l Feb. 3, 1942. P B, PARKS ETAL 2,271,778

' CONTROLLED VOLUME STEAM 'HEATING SYSTEM y Filed May 17, 1940` 4 sheets-sheet 2 fn: [or .ngy

Feb.3,1942. RB. PARKS am, 2,271,778

CONTROLLED VOLUME STEAMHEATING SYSTEM Fells, 1942. P, B,- PARKS ErAL, 2,271,778

CONTROLLED VOLUME STEAM HEATING SYSTEM Filed May 17, 1940 4 Sheets-Sheet' 4 Pau] far/s m1170227 fk5/5776?] Patented Feb. 3, 1942 CONTROLLED VOLUME STEAM HEATING SYSTEM Paul B. Parks, Oak Park, and Emil E. Stenzel, Chicago, Ill., assignors to Vapor Car Heating Company, Inc., Chicago, Ill., a, corporation of New York Application May 17, 1940, Serial No. 335,720

10 Claims.

This invention krelates to a new and improved controlled volume steam heating system, more particularly to a heating system especially useful on railway passenger cars where, due to the increasing number of compartments or zones'in the car, each requiring separate and individual controls, a heating system has become desirable in which a number of separate radiators can be supplied with steam from one controlling regulator through'the medium of one common feed pipe in which a substantially cons-tant volume of steam is maintained automatically at a substantially constant and relatively low pressure.

With the conventional vapor heating systems as used in the past, the practice has been to connect all the radiators in series, and in order to overcome the excessive resistance in such a system a steam pressure in excess of that actually required for radiating purposes has been necessary .at the inlet end of the radiating system despite the fact that-the discharge end is open to the atmosphere. This excessive pressure has created a number of diiiicult problems in maintaining a satisfactory automatic control system.

The present new system comprises, in addiy ply pipe at a predetermined low but super-atmospheric pressure sucient to overcome the resistance in each of the separate radiating devices. The condensate from all parts of the system is preferably discharged through a single drip member, and the retarding device at the outward end of the supply pipe is adapted to permit a small but adequate flow of steam into the return and drip connections so as to keep these pipe connections warm and prevent freezing of any liquid therein.

None of the returning condensate or gases come in contactl with the thermostatic device of of the steam regulator which governs the flow of steam from the source to the supply pipe.

The steam regulator used in this system-is very sensitive and comprises a positive shut-off Valve coupled to a thermostatic bellows that allows the valve to open wholly or partially as may be necessary as the bellows contracts. The

bellows is surrounded by a fined housing to ac- 55 celerate the heat dissipation and is adapted to move the valve to a modulated or balanced position so as to permit just sufficient flow of steam into the supply pipe to maintain the desired Volume of steam therein at the desired low pressure. In a lconduit leading from the low pressure side of the regulator to the chamber containing the thermostatic bellows, and forming substantially a part of the regulator, is positioned a limiting valve adapted to partially open and permit a restricted flow of steam to the thermostatic chamber Ywhen the steam pressure at the outlet side of the regulator and in the supply pipe has risen to a predetermined desired low pressure, for example, five pounds to the square inch. This restricted ow of steam to the bellows chamber will be modulated so as to cause just suiicient expansion of the bellows or economydiaphragm to move the cut-off valve to a balanced position just adequate to permit the desired steam flow into the supply pipe.

Since all of the condensate and discharged fluids returned from the radiating systems and the supply pipe are discharged through a common, heated drip connection without any contact with the diaphragm or bellows of vthe regulator, there is no disturbing factor due to the presence of these relatively cold iiuids which would upset the delicate balance of the steam regulator.

Due to the fact that the radiator valves are separately operated by individual thermostats and therefore turn on and off frequently, the demand on the steam supply in the main supply pipe will vary considerably at different times and it will be evident that the s-team regulator must be quite sensitive so as to maintain the desired volume of steam in the supply pipe at all times, and the mechanism assembly hereinafter described is designed to maintain this desired condition.

Means is also provided for keeping steam out of the branch supply pipesor risers, and the inlet valve, leading to the respective radiators or radiating systems, when the inlet valves are closed, thus eliminating undesirable heating from these pipes and valves when no additional heat is desired in the spaces heated by such radiating systems.

The principal object of this invention is to provide an improved controlled volume steam heating system of the type briey described hereinabove and disclosed more in. detail in the specifications which follow.

Another object is to provide an improved means for maintaining a substantially constant volume of steam supply at a predetermined loW but super-atmospheric pressure, for delivering steam to the several radiators.

Another object is to provide improved means for preventing undesired heating from the steam supply connections leading to the individual radiators.

Another object is to provide means for warming the drip connections leading from the several parts of the heating system so as to prevent freezing in the exposed piping.

Other objects and advantages of this invention will be more apparent from the following detail description of certain approved forms of apparatus designed and assembled so as to operate according to the principles of this invention.

In the accompanying drawings:

Fig. 1 is a diagrammatic elevation showing a portion of one approved form of the heating system.

Fig. 2 is an elevation, similar to Fig. 1, showing a somewhat modified form of system in which shorter supply and return pipes are used.

Fig. 3 is a longitudinal vertical section, on a larger scale, through one of the solenoid-controlled radiator inlet valves, together with a portion of one of the radiators supplied with steam from this Valve.

Fig. l is a partial View of the piping connections for conducting steam from. the main supply pipe to the radiator inlet Valve.

Fig. 5 is a longitudinal vertical section, on a larger scale, through the Water-seal device used in these supply connections, this View being taken substantially on the line 5 5 of Fig. 4.

Fig. 6 is a Wiring diagram showing the electrical connections for controlling the valve shown in Fig. 3.

Fig. 7 is a longitudinal vertical section through the steam regulator, this view being taken substantially on the line 'I-'I of Fig. 1 but on a much larger scale.

Fig. 8 is a longitudinal vertical section through the pressure limit valve.

Fig, 9 is a transverse vertical section through this valve taken substantially on the line 9-9 of Fig. 8.

Fig. 10 is a longitudinal vertical section through the retarding valve used at the end of the supply pipe.

Fig. 11 is a detail perspective, partially7 in central section, through a different form of outlet port and valve-seat for use in the valve shown in Fig. 10.

Referring first to the general assembly shown in Fig. 1, the improved heating system comprises, in general, the main source of high pressure steam A which delivers steam through suitable valved connections including the main steam regulator B to the steam supply pipe C from which steam is individually supplied -to each of the several radiating systems. The ,ftrapor steam-retarder D at the end of supply pipe C cooperates with the pressure limit valve Ey to control the steam regulator B and keeps the supply pipe C filled with steam at a predetermined low but super-atmospheric pressure. Each radiator F is supplied with steam through an electrically controlled inlet valve G, the steam flowing from supply pipe C through a branch supply pipe or riser connection including the Water-seal H, the function and operation of which will be hereinafter described in detail.

The condensate from the radiator drains out through a return branch connection including v the retarding device J into the main return pipe K from which the water drains out to the atmosphere through the drip pipe L. The condensate from the steam used in controlling the steam regulator B also ows out through this drip device L. The retarding device D not only holds back the steam in supply pipe C so as to help in maintaining the desired pressure in this pipe, but also functions like a trap to permit the escape of condensate formed in this supply pipe C, and also permits a limited flow of steam, as well as v this condensate, into the return pipe K, this restricted steam flow serving to keep the return pipe and drip connection L at a sufficiently warm temperature to prevent freezing of liquid in these exposed pipes. The floor of the car is indicated at I, the spaces in the car being divided by vertical walls or partitions 2 into separate compartments each of which contains and is heated by one of the radiators F. A thermostat M positioned in this compartment and responding to temperature changes therein serves, through suitable electrical connections, to control the inlet valve G.

The sour-ce of steam A, as here shown, is the main train-pipe which extends throughout the length of the train and is supplied with steam from the locomotive. The steam in this pipe will normally be under a rather high pressure, for example 250 pounds. A branch supply pipe 3 leads from train pipe A to the main inlet port of the steam-regulator B. In this pipe 3 is located a main cut-01T valve 4 which will normally be open, and a reducing valve 5 adapted to materially reduce the pressure of the steam supply to the regulator B, for example to about 20 pounds per square inch. In order to have this regulator B operate to the best advantage it is desirable not to supply steam thereto at too high a pressure, and for this reason the reducing valve 5 is interposed between the main steam source and. the regulator.

The steam-regulator B operates similarly to so-called vapor regulators already known in the art, except that this regulator is preferably much more delicate in its operation so that the main control valve which is usually moved abruptly from a fully closed to a fully open position may be adjusted to selected partially closed positions so as to modulate or reduce the steam flow through the regulator without entirely opening or closing the valve. The improved regulator as partially shown in Fig. '7 is substantially of the type disclosed and claimed more in detail in the copending application of Parks and Peterson, Serial No. 288,104, filed August 3, 1939. For the present purposes this regulator may be briefly described (referring to Figs. l, 2 and 7) as comprising a casing 6 supported by a suitable bracket 'I and formed with an inlet chamber 8 into which steam flows through port 9 from the supply pipe 3. The steam flows from inlet chamber 8 through strainer I0 andpassage II i'nto the outlet chamber l2 and thence through port I3 into the inlet end portion of supply pipe C from which the radiators are supplied. Steam also flows from outlet chamber l2 through a second port similar to I3 but disposed in the opposite Wall of chamber I2, and thence through pipe I4 (Fig. 1) into the pressure-limit valve E, hereinafter described Themovable valve member I5 is guided in cage I6 so as to engage and cooperate with valve seat I'I at the outlet of passage II to cut olf the flow of steam from inlet chamber 8 into outlet chamber I 2. The spring I8 surrounding valve stem I9 tends to move valve I5 toward the open position shown in Fig. '1.

A thermostatic member indicated generally at 20 is housed in a chamber 2| formed in a separate casing 22 provided With'a plurality of outside radiating ribs 23 so as to expedite the lowering of the temperature around the thermostatic member when steam is no longer admitted to the thermostat chamber 2 I. Thermostatic member 20 comprises an outer bellows diaphragm 24 and contains a quantity of heat-responsive fluid so that when the thermostatic member is directly exposed to steam it will expand thereby forcing outwardly (to the right Fig. '1) the stem 25 which projects through a sealing member 26 and engages at its outer end the lower arm 21 of a lever pivoted adjustably intermediate its length at 28. The upper arm 29 of this lever is adapted to engage and push inwardly (toward the left Fig. 7) the stem 30 which projects into' sealing member 3| andis adapted to engage valve stem I9 and force the valve I5 toward its seat against the opposition of spring I8..

In the usual vapor-regulator as usediin an ordinary vapor heating system, after the radiating system has been filled with steam the excess steam will 'flow back through a return pipe into the chamber housing the'thermostatic member and thereby close the Valve I so as to cut 01T further flow of steam into the radiating system. In the present improved system, steam and other fluids returned from the radiating system or systems do not flow back into thermostatic chamber 2l but are separately disposed of as hereinafter described. In this present improved system the outlet ends of the supply pipe C and the several individual radiating devices are not directly open to the atmosphere but on the contrary the outflow of steam is substantially prevented by the retarding devices Dand J respectively. As a consequence, as further steam is admitted from the source to pipe C through regulator B, the pressure of the steam in supply pipe C and the supply chamber I2 of the regulator will be built up. At the same time steam at this same increased pressure will flow from outlet chamber I2 of the regulator through pipe I4 into the pressure limit Valve E shown more in detail in Figs. 8 and 9.

This improved pressure limit valve E comprises a main casing 32 formed at opposite ends and at one side with three alternative threaded ports 33, 34 and 35 all leading into or from the steam chamber 36 separated by internal web 31 from the upper outlet steam chamber 38. The pipe I4 leading from chamber I2 of the regulator B extends into one of the inlet ports 33, 34 or 35. In the example herev shown pipe I4 is threaded into the port 35. The other two ports 33 and 34 are closed by suitable plugs 39. Alter-` natively, this pressure-limit valve might be inserted midway the length of a pipe without interfering with the free flow of steam through this pipe, in which case the two sections of the pipe would be connected into the opposite pair of ports 33 and 35. A pipe 40 leads from the outlet port 4I of the upper steam chamber 38 down into the inlet port 42 of the thermostat chamber 2I of regulator B (see Fig. 1), this port 42 being opposite the similar outlet port 42 shown in Fig. 7.

A cage structure 43 is threaded at its lower end 44m a vertical passage formed in web 31, this cage having a central passage 45 closed at its lower end by the perforated strainer 46 and formed at its upper end with valve seat 41. Open passages 48 in the sides of cage 43 permit steam to flow from passage 45 into the upper steam chamber 38. The valve 49 which cooperates with valve seat 41 is carried by stem 59 slidable through guide-plug 5I mounted "in the upper end of cage 43. The compression spring 52 is confined between a pair of similar spring-cups 53 and'54, the cup 54 being held between the nuts 55 adjustably threaded on the upper end portion of valve stem 50. The spring-cup 53 bears against the under surface of the closure plate 56 held by screw bolts 51 against a gasket 58 to close the open upper end of the main valve casing 32. The spring 52 will be so adjusted (by changing the position of nuts 55) that the valve 49 will be heldy down against seat 41 until a predetermined steam pressure, for example 5 pounds, is built up in the lower steam chamber 36, which pressure will correspond with the pressure in outlet chamber I2 of the steam regulator B, and also `the pressure in supply pipe C. As this steampressure rises above this pre-determined pressure the valve 49 will be lifted from its seat against the opposition'of spring 52 so as to admit steam into the chamber 38 from which this steam will flow through pipe 40 into thethermostat chamber 2| of the regulator B. lThe spring 52 is of such a type that the spring-load will increase rapidly as the spring is compressed, consequently the valve 49 will only be lifted slightly from its seat so as to permit only restricted flow of steam'through the conduit hereinabove described to the thermostat chamber of the regulator. As a consequence the thermostatic bellows will only be slightly expanded so as to only partially close the Valve I5 and decrease the flow of steam into chamber I2V and supply pipe C. The parts will quickly assume a balanced position in which valve I5 is only open to an extent suicient to admit enough steam -to keep up the desired steam pressure (for'example 5 pounds per square inch) in the supply pipe C. Obviously, as a greater or lesser number of radiators F are supplied with steam from supply` pipe C, the volume of steam admitted to pipe C must-be increased orv decreased, and a rebalancing of the regulator B will be necessary eachtime a radiator is put in or out of service. Since the electrically controlled valves VG are vrather frequently opened and closed `by the thermostatically controlled connections as vhereinafter described, it will be apparent that a more or less constant rebalancing of the regulator Bis required in order to control the volume of steam availablein supply pipe C at arelatively constant low pressure. However, since none of the returned fluids, at lowtemperature,"are returned to the regulator B as in the Y ordinary vapor heating system, the required balance in regulator B is much more accurately and simply maintained since all of the steam Vwhich controls the expansion'of thermostatic bellows 20. comes directly from supply chamber I2. through the pressure-limit valve E.

One-of the individual radiating systems will now be described, it-being understood that there will be one of these'systems for each separate compartment of the car, and as many as six or more of these separate systems can be individuallysupplied with steam from the same supply pipe C. Anpreferred form of inlet valve G and radiator F isy indicated'in Fig. 3, the Valve being shown in more detail and claimedfin the copending application of Parks and Peterson, Serial No. 335,719, filed of even date therewith.

While any suitable type of radiators might be used, the preferred form of radiators F as here shown are of the inner-feed type (Figs. 1, 2 and yIl) comprising a pair of `concentric: or coaxial pipes 59 and 60, the outer pipe 60 being provided with a plurality of radiating ns 6I and being closed at one end by a cap member 62. Steam flows from the outlet chamber 63 of valve G through outlet port 64 into which the inner end 65 of the inner radiator pipe 59 is threaded and thence through pipe '59 which terminates short of the cap 62. The steam then flows back through the annular space 66 between pipes 59 and 60 into the discharge chamber 61 of the valve and out through the branch return pipe 68. The outer radiator pipe 60 is threaded into the inlet port 69 of chamber 61. The main valve casing 'I0 is formed with a steam chamber 1| into which steam is delivered through inlet port 'I2 from the supply pipe 13 extending from the main supply pipe C. A passage 14 extends from chamber 1| to the outlet chamber 63 from which steam is delivered to the inner radiator pipe 59 as already described. A cage structure has a hollow nipple 16 threaded into the inlet end of passage 14, and a movable valve member 11 guided in cage 15 is adapted to engage valve seat 18 in the cage and cut off the flow of steam into the radiator. When the valve 11 is moved back from seat 18 steam will flow from supply chamber 1|, as already described, into and through thel radiator F. When valve 11 is closed against the valve seat 'I8 the supply of steam to the radiator F will be cut off. The valve stem 19 extending rearwardly fromI valve 11 is slidably guided through the rear head portion 80 of the cage, and valve stem 19 carries at its outer end a collar member 8| comprising an outstanding flange or projection 82 which forms a portion of the manually operated Valve-moving mechanism hereinafter described. A compression spring 83 is conned between the end of the cage and collar 8|, this spring normally functioning to move valve 11 to the open position shown in Fig. 3. A solenoid assembly indicated generally at 84 is tted at one end into casing 10 against gasket 85 so as to close this end of steam chamber 1|. The circuit wires 86 and 81 extending from the Aopposite ends of the solenoid coil 88 lead out through the conduit 89. The movable core 90 of the solenoid will be drawn in (toward the left Fig. 3) when the solenoid is energized, and the bearing rod 9| extending from one end of core 90 will engage the end of valve stem 'I9 and force the valve to closed position against the opposition of spring 83; The valve will be held in this closed position as long as the solenoid B8 remains energized. When the energizing circuit is broken, the spring 83 will automatically open" the valve.

A typical circuit for thermostatically actuating wire` 98, rheostat 99, and wire |00 to the other power main IOI. The strength of the current in heating coil 95, and hence the amount of heat added to the thermostat, will depend upon the manual adjustment of rheostat 99 which will be suitably calibrated so that a plurality of desired temperatures may be selected within the compartment. While the thermostat M is directly responsive to temperature changes within the compartment, the actual compartment temperature at which the mercury column will engage the upper xed contact 94 is dependent upon the amount of auxiliary heat added to the thermostat by coil 95. The relay coil |02 is normally energized over the following circuit: From main 96 through resistance |03, relay terminal |04, relay coil |02, relay terminal |05, and resistance |06 to the other power main |0I. When the relay is so energized it will lift the core |01 so as to open the switch |08 and thus deenergize the valve solenoid 88 which is controlled through the following circuit: From main 96 through wire |09, switch |08, wire 86, solenoid coil 88, and

and controlling this valve is shown diagrammatically in Fig. 6. The thermostat indicated generally at M (see also Fig. 1) is positioned at some suitable location in the compartment or space heated by radiator F, this thermostat comprising a mercury column 92 which is always in engagement with a lower fixed contact 93 and which engages an upper fixed contact 94 at some predetermined temperature. An auxiliary heating coil 95 is associated with the thermostat, this coil being energized over the following circuit: From power main 96 through wire 91, coil 95,

wire 81 to the other main |0I. With solenoid 88 deenergized, the spring 83 will open the valve 11 and admit steam to the radiator F. When the desired temperature is reached in the compartment, the mercury column 92 will engage the upper thermostat contact 94 and thus complete a shunt circuit as follows: From one terminal |04 of the relay coil through wire I|0, mercury column 92, and wire ||I to the other terminal |05 of the relay. This will deenergize the relay so that switch |98 will automatically close and solenoid 88 will be energized to close valve 11 and cut off the flow of steam to the radiator. Similarly, when the temperature within the compartment falls below the temperature for which thermostat M is set, the shunt circuit will be broken and relay |02 will again b'e energized to open switch |08 and deenergize solenoid 88 so that spring 83 will again open the Valve 11 and admit more steam to the radiator. This is the position of the parts indicated in Fig. 6.

The valve G can also be manually operated. Referring to Figs. 1 and 3, a disk I3 is fixed on an operating shaft II4 extending transversely through the upper portion of steam chamber 1I. An arcuate recess I I5 is formed within one peripheral portion of disk II3, and the flange or projection 82 on collar 0| of the valve stem assembly extends into the arcuate recess I5. When disk II3 is in the central position indicated in Fig. 3 the core 99 and valve 11 can be reciprocated longitudinally so as to open or `close the valve under the electrical control hereinabove described. A locking detent I I6 is guided for longitudinal movement within the screw-plug II1 and is urged downwardly by spring IIS into yielding engagement with one of the series of recesses II9, |20 and |2`I formed in the upper peripheral portion of disk I I3. When detent ||6 engages the central recess |29, the disk will be held in the intermediate vposition shown in Fig. 3 and the valve will be under electrical control. When disk AI I3 is swung through a suitable arc in a clockwise direction, the shoulder |22 at one end of recess |5 will engage the projection or liange 82 and shift the movable assembly consisting of collar B I, stem 'I9 and valve 11 toward the left (Fig. 3) against the opposition of spring 83, until detent I|6 is moved into recess ||9 thus yieldably locking the valve in closed position. On the other hand, if the disk ||3 is swung through an equal arc in the counter-clockwise direction, shoulder |23 at the other end of the recess H will be moved into proximity to collar 82 and the detent ||6 will be snapped into the other recess |2| thus locking the valve in open position, even though solenoid 88 should be energized. A crank or lever |24' (Fig. 1) secured on one outer end of shaft ||4 is adapted to shift the disk from one to another of the three positions hereinabove described, these three positions of the valve being suitably indicated by handle |24 on a dial formed on the outer surface of the valve casing.

Referring now more particularly to Figs. 1, 4 and 5, steam from the main supply pipe C ows to the radiator F through the branch supply pipe 13 which is connected at its discharge end into valve G as just described,l and which receives steam at its inlet end from the water-seal fitting H connected at an intermediate point in main supply-pipe C. As shown in Fig. 4, this branch supply pipe 13 will usually be of greater length than appears in Fig. 1 since the supply pipe C will be beneath the central portion of the car whereas the radiator F and valve G are positioned near one side wall of a compartment. thus requiring an intermediate laterally extending portion 13 of pipe 13 (see Fig. 4). The fitting H is formed centrally to enclose a steam chamber |25 having aligned ports |26 and |21 in opposite sides thereof into which are fitted the adjacent ends of the two sections of supply pipe C. A depressed central portion |28 of the tting H, closed at the bottom by a removable plug |29, serves to hold an accumulated pool of condensate |30. A cup-shaped web |3|, open at its lower end |32 beneath the level of pool |30, projects downwardly from the upper portion of casting H within the steam chamber |25, this web enclosing a central outlet chamber |33 having an upper outlet port |34 into which the lower end of branch pipe 13 is secured. A quite small vacuum-breaking vent |35 is formed in one side wall of web |3| above the water level of the pool and connecting the inner and outer steam chambers |33 and |25 The function of this water-seal H is to prevent undesired heating of the compartment when the valve G is closed. It will be noted that if, as usual, the inlet Valve G were connected directly with the supply pipe C through a branch riser, steam would still be supplied to the steam chamber 1| of the valve G through riser 13 even when valve 11 is closed. As a consequence, all of the branch supply pipes 13 as well as a large portion of the valve casing would be lled with steam at all times and heat from this steam would be transmitted even to the inlet end portion of radiator F. As a result there would be a partial heating of the compartment even at such times as no heating was required or desired. vReferring now to the operation of the water-seal H, but neglecting for the moment the vent |35 and its function, when the electrically controlled inlet valve is closed the steam in valve chamber 1| and supply pipe 13 will condense thus forming a partial vacuum which will draw up the condensate thus formed as well as the water at the water-seal. As additional steam is condensed in this branch pipe it will be drawnup so as to eventually form a substantially water column which will prevent the ow of steam to the upper portion of the branch supply pipe and valve. The systemas thus far described has one objection, that is when the car is taken out of service and the steam supply is disconnected from the car, the water column in pipe 13 may not flow out and may freeze in the exposed portion of the piping. The Vent opening |35 is provided to prevent this freezing. During normal operation, with valve G open, some steam will flow in through the vent opening |35. When Valve G is closed there will be, as before, an accumulation of water vin the riser 13 drawn up by the vacuum formed in this pipe. There will still be an inflow of steam through vent opening |35 but this small flow of steam will be condensed upon contacting the water column in the pipe. The nal result willbe to prevent any substantial quantity of steam rising in the branch supply pipe to heat the valve structure. When the car is taken out of service and there is no longer a steam supply in pipe C, air willenter through vent |35 so as to break the vacuum and permit the water-column to flow out. There will always remain a small accumulation of water in the pool |33, but it will be noticed that the bottom of this pool is rounded so that no damage will'result from the freezing of this small quantityxof water. l

The steam-retarder D (Figs. 1 and 10)k is formed with a threaded inlet port |36 receiving the threaded end of supply pipe C, and opening into the steam chamber |31. An internal web |38 separates steam chamber |31 from the outlet chamber |39 which has an outlet port |40 which receives the threaded end of return pipe K. The annular collar member |4| threaded into a vertical passager in web l'|33 surrounds the fluidpassage |42 connecting chambers |31 kand |33. An upwardlyprojecting rounded bead. |43 forms a valve-seat surroundingthe upper end of passage |42, this valve seat being engaged by the movable valve member |44 when chamber` |31 is lled with steam so as to expand the sensitive thermostatic bellows |45. The upper xed end of vthis bellows is carried by the closure '|46 re- Inovably attached to the upper end of the main casting of the retarder.

As long as the supply pipe C and chamber |31 are filled with steam, Vthe bellows.|45 will expand so as to hold back this steam and prevent theA flow of any substantial amount into the return pipe K. However, when any condensate` accumulates in the endA portion of supply pipe C the bellows |45 will contract sufficiently to lift the valve |44 and permit this condensate to flow out into chamber |39. and thence through return pipe K. It will be` noted that one or more small notches |41 are formed in the valve-seat |43, these notches permitting v.a very restricted ow of steam into the return pipe at all times, even though the valve |44 is closed. This is for the purpose of keeping the return pipe K warm as will be hereinafter referred to again.

The steam retarders or. traps J (Fig. 1) are substantially the same as the retarder D shown in Fig. 10, the onlychange being that the annular valve-seat |48 shown in Fig. 11 is substituted for the larger valve-seat |4| shown inFig. 10. It will be noted that the centr-al steam passage |49 is considerably smaller than the pas.- sage |42 in the previously described annular member |4|, and the upstanding annular valve-` Seat |50 is of considerably less diameter than the similar valve-seat |43 of Fig. 10. Steam and condensate from the radiator F and valve G flow out through pipe 68 into chamber |31 of the retarder or trap, and suiiicient condensate will cause the bellows |45 to contract and let the condensate flowout through the section 63 of this branch return pipe into the main return pipe K. By providing a smaller valve-seat |58 thereywill be an increased total upward pressure `against thel lower end of the bellows |45 and tending to open the valve when closed so that the retarder or trap J will be more sensitive than the trap D first described and will open more often and more quickly and at a higher temperature to permit the drainage of condensate from the radiators. At the same time the traps will close quickly but quietly so as to prevent the loss of any substantial amount of steam and also to prevent the excessive loss of steam pressure at these retarders J.

The condensate and non-condensable gases collected in main return pipe K through the retarders D and J flow from the lower end of return pipe Kthrough connection into the upper end of the drip pipeLwhich is open to the atmosphere at its lower end. This drip pipe is preferably covered with insulation |52 so as to retain heat. and prevent, so far as possible, the freezing of liquid in this drip pipe. Another pipe connection |53 extends from the outlet port 42 of the thermostatic chamber 2| ofthe steam regulator B into the upper end of drip pipe L so that all condensate from the heating system will be discharged through this same protected drip pipe L.

It will now be noted that there will be a limited amount of steam ilowing from the regulator B through the discharge pipe |53, and also from each of the radiating systems when. the traps J are open, and this steam will ordinarily be sufricient to maintain these pipes above. a freezing temperature. However, if the return pipe K is very long it is desirable to permit. a limited flow of steam into this pipe to prevent water from freezing therein and it is for this reason that the open notch or passage |41 is providedv in the valve-seat |43 ofV retarder D. This small steam flow will be enough to maintain the pipe K above freezing temperature. The steam admitted from all of these sources will also tend to keep the interior of drip pipe L above the freezing tem\ perature. It will be understood that the righthand end of the supply and return pipe loop shown in Fig. 1 is c-ut away and that there -will ordinarily be several more` radiators F supplied with steam from this loop, thus making the de! sirability of supplying a limited flow of steam to the return pipe K more apparent.

Referring now to the modification shown in Fig. 2. it will be noted that there are only two of the radiating units arranged with their supply and return ends adjacent one another so that the return pipe K is quite short. In this case the end retarder D` can be omitted entirely. The steam pressure throughout the system, including supply pipe C, will be kept up by the retarders J. Any condensate accumulating in the short supply pipe C can be blown out through the righthand radiating unit and returned through this unit and the return pipe K. Suflcient steam to keep the vreturn system from freezing will be supplied by the two branch return systems Iand the return from steam regulator B. Practice has indicated that the retarder D with its restricted steam flow will not be required provided the return pipe K is not over about three feet in length. One notch |41 in the valve seat of retarderv D will permit a suicient steam flow for a return pipe K not over ten feet in length. If the pipe K is longer than this, an additional notch |41 or a larger notch should be used.

It will now be apparent that this steam heating system, while resembling the ordinary vaporheating system in some respects, differs materially therefrom in operation. In the ordinary vapor heating system, although the discharge end of this system is open to the atmosphere, it is necessary to maintain a material pressure at the inlet endof the system in order to overcome the quite considerable internal resistance when a plurality of separate radiators are arranged in series. In the improved system here disclosed each radiator or radiating unit draws its steam individually from the same supply pipe and only suiicient pressure to force steam through this single radiator ory radiating system is required. It is, however, desirable to maintain the supply pipe full of steam at all times under this desirable low pressure, despite the fact that the number of separate radiating units in service may be continually changing. For this reason a very sensitive steam-regulator B is necessary, and it is desirable not to return fluids from the system to this regulator in order not to disturb the balanced operation thereof.v The retarders D and J hold back the outflow of steam so that a steam pressure considerably higher than necessary could be built up in the supply pipe C and the separating units. However, the pressure-limit valveA It?.L Will open Whenever this steam pressure rises` above the desired maximum, and the small flow of steam thus returned directly to the thermostatic chamber of the regulator B will serve to throttle the control valve of this regulator so that just suiiicient steam rwill flow from the source into the supply pipe C to replace the steam that is withdrawn, at the desired low pressure, to satisfy the needs of the radiators in service at any one time. If a radiator is added to the system ('by the opening of its valve G) there will be an increase in the Withdrawal of steam from supply pipe C and the valve of regulator B must be opened an additional amount to compensate for this increased load `and at the same time keep the pressure in pipe C up to the desired maximum, for example ve pounds. This is automatically accomplished by the balancing action of the regulator B and the pressure-limit valve E', and is not influenced in any way by uids returned from the radiating system. Should returning condensate be allowed to flow to the thermostatic chamber of the regulator, the action of the regulator would be so irregular as to cause prolonged periods of inactivity with a consequent starving of the radiators. In the present improved system, the thermostatic ele.. ment of. the regulator is controlled entirely and directly by pressure changes inthe supply pipe C, and is not influenced or disturbed in any way by permitting cold. fluids returnedA from the radi-Y ating systems to comey near the controlling thermostatic member. Experience has shown that. this. improved type of heating system makes for greater economy because, with the various valves of generous size and. the resistance through the system decreased due to parallel feeding, steam canl flow through easily and quicklyl when only a small pressure differential is provided between the inlets and outlets of the respective radiating systems` Thissmall but relatively constant pressure dinerential is kept up at all times by the steam supply system disclosed hereinabove.

We claim:

1., In a4 controlled volume steam` heating sys. tem, a source of relatively high pressure steam, a steam supply pipe,y a valved connection between the source and supply pipe, means controlled automatically in response to pressure-.changes in the supply pipe to open or close the valved` con-v nection whereby `the supply pipe is kept lled with steam at a predetermined lowy pressure, a plurality of radiators, and means for independ ently supplying each radiator with steam from the supply pipe, a drain connection having branches leading from each radiator and from the supply pipe, thermostatically operating steam retarder means in each branch drain connection, the retarder means between the supply pipe and the drain including a constantly open orifice to permit a small ow of steam into the drain connections to prevent freezing f fluid therein.

2. In a controlled volumesteam heating system, a plurality of independently operating radiating systems each comprising a radiator, branch supply and return pipes leading to and from the radiator, an inlet valve in the supply pipe, and a steam-trap in the return pipe, a main supply pipe from which all of the branch supply pipes lead separately, a main source of steam, means comprising a steam-regulator for continuously maintaining a supply of steam from the source in the main supply pipe at a predetermined low but super-atmospheric pressure, said regulator comprising a valve and a thermostatic member forthrottling the valve, means actuated by pressure-changes in the supply pipe for feeding steam to the thermostatic member, a drippipe, a return main into which the branch reture pipes discharge, and a discharge pipe leading from the regulator, both the latter discharge pipe and the return main discharging condensate through the drip pipe.

3. In a controlled volume steam heating sysf tem, a source of relatively high pressure steam,

a regulator comprising an inlet chamber communicating with the source, an outlet chamber, a valve controlling the ilow from the inlet charnber to the outlet chamber, a thermostat chamber, a thermostatic member in the thermostat chamber, connections for `adjusing the valve to restrictI the flow of steam as the thermostatic member is exposed to steam temperature, a conduit connection leading from the outlet chamber to the thermostat chamber, a normally closed valve in this conduit adapted to open when the pressure in the outlet chamber rises above a desired maximum, a supply pipe leading from the outlet chamber, a drip member connected at its upper inlet end with the thermostat chamber and at its lower outlet end with the atmosphere, a plurality of radiating devices, an inlet valve for each radiating device, a ris-er leading from the supply pipe to each inlet valve, a condensate return pipe leading into the drip member, branch return pipes leading from each radiating device into the main return pipe, and steam traps positioned one in each branch return pipe.

4. In a controlled volume steam heating system, a source of relatively high pressure steam, a regulator comprising an inlet chamber communicating with the source, an outlet chamber, a valve controlling the flow from the inlet chamber to the outlet chamber, a thermostat chamber, a thermostatic member` in the thermostat chamber, connections for adjusting the valve to restrict the flow of steam as the thermostatic member is exposed to steam temperature, a conduit connection leading from the outlet chamber to the thermostat chamber, a normally closed valve in this conduit adapted to open when the pressure in the outlet chamber rises above a desired maximum, a supply pipe leading from the outlet chamber, a drip member connected at its upper inlet end with the thermostat chamber and at its lower outlet end with the atmosphere, a plurality of radiating devices for independently hatingseparate spaces, an inlet valve for each radiating device, thermostatic means forv independently opening or closing each inlet valve in response to temperature changes in the space heated by the individual radiating device, a riser leading from the supply pipe to each inlet valve, a condensate return pipe leading into the drip member, branch return pipes leading from each radiating device into the main return pipe, and steam-traps positioned one in each branch return pipe.

5. Ina controlled volume steam heating system, a source of relatively highl pressure steam, a regulator comprising an inlet chamber communicating with the source, an outlet chamber,

a valve controlling the flow from the inlet chamber to the outlet chamber, a thermostat chamber, a thermostatic, member in the thermostat chamber, connections for adjusting the valve to restrict the `flowof steam 4as the thermostatic member is exposed to steam temperature, a conduit connection leading from the outlet chamber to the thermostat chamber, a normally closed valve in this conduit adapted to open when the pressure in the outlet chamber rises above a desired maximum, a supply pipe leading from the outlet chamber, a drip member connected at its upper inlet end with the thermostat chamber and at its lower outlet end with the atmosphere, a plurality of radiating devices, an inlet valve for each radiating device, a riser leading from the supply pipe to each inlet valve, a condensate return pipe leading into the drip member, branch return pipes leading from each radiating device into the main return pipe, steam-traps positioned one in each branch return pipe, and a steam-trap between the outlet end of the supply pipe and the return pipe, said last-mentioned trap having a constantly open restricted passage to permit a small continuous ow of steam into the return pipe.

6. In a steam heating system, a steam supply pipe, a radiator 'positioned at a higher level, an inlet valve at one end of the radiator, a waterseal tting connected in the supply pipe and adapted to accumulate a pool of water in the lower portion of the fitting, a chamber formed in the upper portion of the iitting having an upper outlet port and having an inlet opening in its bottom leading from below the water-level, the fitting providing for a free Iiow of steam through the supply pipe above the water level and past the chamber, and a steam-riser leading from the outlet port of the chamber upto the inlet valve, there being a small uid passage connecting the supply pipe with the chamber above the water level.

7. In a steam heating system, a steam supply pipe, a radiator positioned at a higher level, an inlet valve at one end of the radiator, a waterseal fitting connected in the supply pipe and adapted to accumulate a pool of Water in the lower portion of the fitting, and a conduit leading from below the water-level of the pool up to the inlet valve there being a small uid passage in the side wall of the lower portion of the conduit above the water-level, but within the tting.

8. In a low pressure steam heating system, a source of steam, a supply pipe receiving steam from the source, a return pipe, a plurality of radiators each receiving steam from the supply pipe at different locations between its inlet and outlet ends and returning condensate to the return pipe at locations between its inlet and outlet ends, and a, restricting valve connecting the outlet end of the supply pipe and the inlet end of the return pipe, the valve comprising a constantly open small orifice and a normally closed large orifice, a closure for the large orice thermostatically moved to closed position when exposed to steam in the supply pipe, the small orice admitting only sulicient steam to the return pipe to maintain this pipe and its liquid contents above freezing temperature.

9. In a low pressure steam heating system, a source of steam, a supply pipe receiving steam from the source, a return pipe, a plurality of radiators each receiving steam from the supply pipe at diierent locations between its inlet and outlet ends and returning condensate to the return pipe at locations between its inlet and outlet ends, and a restricting valve connecting the outlet end of the supply pipe and the inlet end of the return pipe, the valve comprising a constantly open small orice and a normally closed large orice, a thermostatic bellows positioned in the path of the steam in the supply pipe and serving at its closed movable end as a closure for the large orifice, the small orifice admitting only suicient steam to the return pipe to maintain the return pipe and its liquid contents above freezing temperature.

10. In a low pressure steam heating system, a source of steam, a supply pipe receiving steam from the source, a return pipe, a plurality of radiators each receiving steam from the supply pipe at dilerent locations between its inlet and outlet ends and returning condensate to the return pipe at locations between its inlet and outlet ends, and a restricting valve connecting the outlet end of the supply pipe and the inlet end ofv the return pipe, the valve comprising a large orlce with a valve seat at its inlet end, a closure adapted to engage the valve-seat, a thermostatic member actuated by steam in the supply pipe to move the closure to seat-engaging position, there being a constantly open notch formed in the valve-seat for permitting a limited flow of steam therethrough at all times to maintain the return pipe and its liquid contents above freezing temperature.

PAUL B. PARKS. EMIL E. STENZEL.

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