US1960937A - Steam pressure regulating means - Google Patents

Description

May 29, 1934. F. w. DEARBORN STEAM PRESSURE REGULATING MEANS Filed March 8, 1955' 2 Sheets-Sheet 1 W R ,W Y. b E H N L H E O T N w m gm-h /fll V/ yr B .J

y 1934. F. W. DEARBORN ,960,937

STEAM PRESSURE REGULATING MEANS Filed March 8, 1933 2 Sheets-Sheet 2 INVENTOR JAMIA W WW) ATTORNEYS heat radiator 20 supplied with steam by a feed- Patented May 29, 1934.

UNITED STATES 7 STEAM PRESSURE REGULATING MEANS Frank W. Dearborn, Brooklyn, N. Y., assignor to Gold Car Heating & Lighting Company, Brooklyn, N. Y., a corporation of New York Application March 8, 1933, Serial No. 660,009

18 Claims.

This invention relates to improved apparatus adapted for use as parts of steam heating systems and systems adapted for the distribution of steam for other purposes.

It is an object of the invention to provide means for distributing steam for local use ata substantially constant low pressure irrespect-ve of material variations of pressure in a relatively high pressure source of supply.

. It is a further object to provide improved means for controlling the admission of steam from the source of supply to the part of the system to be maintained at a relatively low pressure, and improved means whereby water of condensation may be freed from the low pressure part of the In the accompanying drawings illustrating pre' ferred forms of the invention;-

Figure 1 is a conventional perspective view of one form of steam heating system embodying the invention.

1 Fig. 2 is a cross-sectional view through a combined, normally open, steam trap and check valve of limited checking capacity used as a part of the systems illustrated in Figs. 1 and'4.

Fig. 3 is a cross-sectional view through a steam regulating valve used as a part of the systems illustrated in F. gs. 1 and 4.

Fig. 4 is a conventional perspective view of a modified form of steam heating system embody- I ing the invention.

Fig. S-is a cross-sectional view through a steam regulating valve used as a part of the system illustrated by Fig. 4.

The comb ned check valve and steam trap illustrated in Fig. 2 is a modification of a device of the prior art adapted for use as a steam trap only, and the regulating valves illustrated in Figs. 3-and 5 are devices of the prior art which are not intended to be covered by claims to be presented in this case other than when used in comb'nation with other parts of the disclosed apparatus.

In Fig. 1 the invention is illustrated as applied to heating apparatus of the kind commonly used in the heating of railway cars. It comprises a pipe 21 connected with the usual train pipe 22'.

The flow of steam from the train pipe to the radiator is controlled by a regulatingvalve 23 illustrated in detail in Fig. 3. This valve com-- prises inlet and outlet ports 24, 25, respectively,

and a valve disk 26 which may be seated to close a normally open port 27 against the opposing effort of a spring 28 by means of any suitable thermomotive device 29. The valve may be provided with a steam chamber 30 in a sufliciently' close association with the thermomotive device 29 to cause the same to be expanded when heated by the steam in the chamber and, through the intermediary of the valve stem 31, thrust the valve disk 26 against its seat and close the port 27. If desired, the steam chamber 30 may be in direct communication with the chamber 32 in the body portion 33 of the regulating device, in which the thermomotive device is mounted.

The steam chamber may be provided with an exhaust orifice 34, preferably open to atmosphere, for draining away water of condensation, and with one or more inlet orifices 35, 36, to be connected with parts of the d.stributing system which will hereinafter be described.

The exhaust orifice 34 of the regulating valve may be provided with a downwardly-directed horn 37 by which the thermomotive device may be quickly cooled when steam is not being supplied to the chamber 30, in order that thevalve 27 may be held closed only so long as steam or hot water vapor is being supplied to the chamber 30 at one or more of the inlets 35, 36.

In the preferred form of the invention illustrated in Fig. l the exhaust outlet of the radiator is connected with the steam chamber of the regulating valve by means of return piping 38, 39, in which is included as at 49 a combined steam trap and check valve of limited checking capacity, one satisfactory form of which is shown in Fig. 2.

The steam chamber of the regulating valve is also connected with the feed pipe 21 by piping' 41, 42, within which is included a second combined steam trap and check valve 43 of I'mited checking capacity, which may be identical with the one designated in the radiator return piping.

The combined steam trap and check valve, specimens of which are used as a part 'of the invention iIIustrated in Fig. 1, as more clearly shown 'in Fig. 2, comprises a Valve casing44, having an inlet orifice 45, an outlet orifice 46, a port 47, and a thermomotive element 48, the end 49 of which, when expanded, may be thrust against its seat 50 and close the port 4'7. The thermomotive element 48 may be of a well-known construction comprising a hollow, expansible chamber partly filled with a volatile liquid adapted to be vaporized when heated by steam in the piping leading to the inlet orifice 45 and port 47 of the valve. The thermomotive element 48 may be mounted upon a plug 48 having a threaded connection with the valve casing 44.

A device quite similar in some respects to the valve illustrated in Fig. 2 having a conical metal valve disk on the end 49 of the thermomotive element 48 to-close the port 47 has been used in the prior art as a thermostatic steam trap, the orifice 46 being used as the inlet orifice and the orifice 45 as the outlet orifice. The valve of the prior art, however, is purely a steam trap and in no proper sense a check valve. The presence of steam in the piping leading to the orifice 46 of the valve, when used asit is commonly used in the prior art, would expand the thermomotive element and close the valve, but the valve when so used was not intended or designed to open at a predetermined pressure. The accumulation of water of condensation at the orifice 46 would cool thethermomotive element 48 and cause it to open the valve and permit the waterof condensation to be discharged, but as soon as steam again came in contact with the thermomotive element'the valve would again close and remain closed irrespective of pressure.

The important discovery has been made that by omittng the conical valve disk, lengthening the thermomotive device 48-and using the orifice 45 instead of the orifice 46 as the inlet ori'- of. the end. 49 of the thermostatic element which is opposed only bythe expansive force of the thermostatic element, so that by properlyapportioningthe area of the-port 47 to the di-.

mensions of the thermomotive. element 48 and volatile fluid used in said element, the valve may be designed to open at any desired predetermined pressure and to close again as soon as the pressure drops below that predetermined pressure if j; steam is still present in the pipe leading to, the

inlet orifice .45 and port 47, the, thermomotive element 48 will cool and contract, thus letting the water pass through the valve and out through thermomotive element 48 has been lengthened so that the volatile vfluid in the thermomotive element may be brought into a sufficiently close association with the steam at the inlet orifice;

of the valve to maintain the valve closed.

If desired, for a purpose which w'llbe-explained, piping 51,52 may be so connected as to form a by-pass around the checkvalve 40 and.

a valve 53 may be provided-to control the flow of steam and water of condensation through the bypass. It --may alsobe desired to provide-a valve 54 by means of which the admission ;of.. steam to theradiator 20 may be controlled, anda valve 55 mayalso be provided to close the connection between .the train pipe and the regulatng valve 23.

For reasons to be explained, a valve 56 may be provided to control the flow of steam through the branch piping 41, 42.

The heating system illustrated in Fig. 1 may be operated in various ways. If the valves 55 and 53 are opened and the valve 56 closed, the system may be operated as an ordinary vapor system of the prior art. Steam from the train pipe 22 will pass through the feed pipe to the radiator and through the by- pass connection 52, 51 to the steam chamber 30 of the regulating device and be exhausted to atmosphere. The steam in the steam chamber will cause the regulating device to close and prevent further admission of steam.

As long as heated vapor is present at the exhaust end of the radiatorno further steam will be admitted. As soon as the steam at the exhaust end of'the radiator has'become condensed, the thermostatic element of the regulating valve 23 will permit the valve to open slightly and admit more steam.

.Theadmission of steam to theradiator whenoperating. as part of a vapor system may be controlled by the radiator valve 54.

If Without making any other change in the sys tem the-valve 53 isclosed, the pressure at the return end of the radiator will be increased to a predetermined pressure dependent upon the construction of the valve 40. This pressure might, for example, be maintained at five pounds by the valve 40 irrespectivev of the pressure inthe train pipe. Pressure in the pipe 38 exceeding five pounds would cause the valve 40 toopen and permit steam to be admitted through pipe 39 to the steam chamber 30 of the regulating valve and close the valve. Any accumulation of Water of condensation in the pipe 38 leading to the valve 40 would cause the valveto be tempo-- rarily cooled and opened without respect to pressure and permitwater-of condensation to 7.

pass through pipe 39 to the regulating valve andbe discharged through the horn 37. Thevalve,

however, wouldremain closed so long as steam were present at the orifice 47 and the pressure didnot exceed five pounds. .The closing of the valve 40 would cause the thermostatic element of the regulating valve 23 to cool and admit more steam. The result would be that the valve 40 Would constantly pass just sufiicient steam to maintain the pressure atthe return end of the radiator at the desired pressure of five pounds, The pressure at the admission end of the radiator would be slightly greater due to the condensation of steam in the radiator.

When using the system in either of the two ways thus far described, it will be observed that if the valve 54 is closed to prevent the admission of steam tothe radiator, no steam will be admitted to the steam chamber of the regulating valve and the valve 23 will remain open. The valve 54willthereforehaveto be capable of sustaining the full pressure of the steam in the train pipe. Moreover, when the valve 54 is opened there is a sudden rush of high pressure steam from the train pipe through feedpipe 21 to the radiator, which i will not be checked until steam has filled. the radiator and-passed through piping,52, -51, to the steam chamber of the regulating valve. It is one of the objects of the invention to prevent this rush train pipe. This has been effected by the use-0t the branchpiping 41, 42-and checkvalve43; To

obtain the benefityof this improved feature of the invention, the valve 56 is opened, and when using the apparatus embodying the invention in accordance with what is regarded as the preferred mode of operation, the valve 56 is never closed. With this valve 56 open it will be apparent that when the system is thrown into operation by opening the valve 55, a part of the steam which is forced through pipe 21 passes through piping 42, 41, to the steam chamber 30 of the regulating valve. There is no initial check to the flow of steam through piping 42, 41 because the valve 43 is normally open. This first rush of steam puts the regulating valve 23 in immediate control of the system and prevents any material rush of high pressure steam into the radiator 20.

The first flow of steam through valve 43 heats the valve and causes it to close, so that the thermomotive element of the regulating valve will begin to cool due to ventilation through the horn 3'7 and valve 23 will commence to open and slowly admit steam through feed pipe 21 to the radiator. Should the pressure of steam in pipe 21 exceed a predetermined pressure at which valve 43 may be designed to open, five pounds for example, the disk of valve 43 will be slightly unseated and again permit enough steam to pass to the steam chamber of the regulating valve to check the flow of steam through the valve 23. This will continue until the radiator has been filled, the pressure at the inlet end of the radiator being maintained at a pressure not exceeding five pounds. This improvement due to the addition of piping 41, 42 and check valve 43 may be used with valve 53 in the by-pass about valve 40 either open or closed. If valve 53 is open, the device will operate as an ordinary vapor device, except that the flow of steam when admitted to the system by opening valve 55 will be checked as has already been explained. The pressure at the return end of the radiator would be substantially equal to atmospheric pressure, and the pressure at the admission end only so much greater as to provide for condensation. With the valve 53 open and the system once in operation, the valve 43 would not ordinarily be again opened since the pressure in the entire system would be maintained at a pressure only slightly above atmospheric pressure due to the steam admitted to the steam chamber 30 of the regulating valve through the return connection 51, 52.

When it is desired to operate the system as a low pressure system and at the same time take advantage of the controlling effect of valve 43, valve 53 must be closed. When so operated the pressure-reducing effect of the valve 43 when first admitting steam to the system will be substantially the same as it was when operating the system as a vapor system. On first admitting steam to the radiator with valve 56 open and valve 53 closed, any water of condensation would first be driven out of the system through the normally open valve 40. This would be followed by steam which would immediately heat the thermomotive element of the valve 40 and close it. Steam would then continue to be fed to the radiator at a rate such as to maintain a pressure of five pounds at the admission end. Any drop below a pressure of five pounds would permit valve 43 to close, as a result of which the thermomotive element of the regulating valve 23 would be cooled and permit steam to flow from the train pipe through pipe 21 until again checked by the opening of valve 43 at a pressure slightly above five pounds. If the valve 40 were also designed to open at a pressure of five pounds, it would never be opened during the operation of the system in the manner just described due to steam pressure, since the pressure at the exhaust end of the radiator would always be slightly lower than the pressure at the admission end due to condensation of steam in the radiator. Any accumulation of water, however, in the return pipe 38 would cause valve 40 to be cooled and open, as a result of which the water would be drained away until the presence of steam in the return pipe 38 would cause the valve to again close.

If valves 43 and 40. were to be designed to open at the same pressure, five pounds for example, the pressure. in the radiator, when op-.

erated with valve 53 closed, might be slightly increased and diminished at will by closing and opening the valve 56. By operating the system with the valve 56 open, the pressure at the ad'- mission end of the radiator would be limited to a pressure of five pounds, and the pressure at. the exhaust end would be sli htly lower to an.

extent dependent upon the rate of condensation of steam in the radiator. With the valve 56 closed, the pressure at the exhaust end or the radiator would be maintained at a pressure of. five pounds by valve 40 and the pressure at the admission end would be higher to an extent dependent upon the rate of condensation of steam' pressure in the radiator would increase until the pressure at the return end would be raised to a pressure of ten pounds.

It is not necessary for all purposes that valves 40 and 43 be each designed to operate as a combined steam trap and check valve of limited checking capacity.

If piping 21 and 42 be so arranged as to drain water of condensation back to the train pipe, it is not essential that valve 43 be one capable of serving as a steam 'trap. Any relief valve, whether thermostatically operated or otherwise, capable of opening when subjected to the desired pressure would satisfactorily serve the desired purpose.

When operating the system with valves 56 and- 53 closed, so that the admission of steam to the feed pipe 21 as controlled by the regulating valve 23 is dependent upon valve 40, valve 40 must act as a check valve of limited checking capacity in order that an abnormal increase of pressure in the radiator may open the valve and cause steam to flow to the regulating valve and close the same, and when so operated the valve 40 must also be one adapted to serve as a steam trap unless some other means is provided for freeing water of condensation from the radiator.

When operating the system with valve 56 open and valve 53- closed, it is not important that valve 40 be designed to operate as a check valve of limited checking capacity, nor is it even necessary that it be connected with the regulating valve 23. All that is essential under such conditions of operation is that it serve as a steam trap capable of freeing the radiator of water :purpose. I

of condensation while preventing the escape of steam.

The system as illustrated by Fig. 1 is so designed that, when operated with valve 53 open,

Water of condensation may drain directly from the radiator through piping 52, 51, 39 and drip horn 37, to atmosphere. If, however, valve 40 is so designed as to drain water of condensation from the system except when steam is present in the pipe 38; piping 51, 52 and valve 53 need not be so designed as to avoid the trapping of water in the return connections from the radiator, since, irrespective of the pressure in pipe 38, valve 40 would always serve as a steam trap and eliminate water of condensation.

In the modified form of the invention illustrated in Fig. 4 the flow of steam from the train pipe 22' to and through distributing piping 21' is controlled by a manually-operated valve and a regulating valve 23', which may be like the one illustrated in Fig. 3 having a similar valve casing 33 and drip horn 37.

As a further means of controlling the flow of steam from the train pipe to and through the distributing piping, the system illustrated in Fig. 4 may be supplied with piping 41, a valve 56 and a check valve 43, all of which may be substantially identical with the parts 41, 56 and 43 of the system illustrated in Fig. 1.

The exhaust end of the distributing piping 21' may be connected with a check valve 40, the exhaust outlet of which may be connected by piping 39' with the steam chamber of the regulating valve 23', 33'. The valve 40 may, if desired, be

i identical with the valve 40 of the system illustrated in Fig. 1.

The distributing piping 21 may serve as a means of supplying steam to any desired apparatus, such, for example, as radiators 20, at a pressure which imay be controlled and varied by the valves 40',

lat which valve 43 opens, then the pressure in the admission end of the distributing piping may be maintained at a predetermined pressure, five pounds for example, by valve 43' while valve 40 merely serves as a means of draining the system oiwater of condensation. When so operated the regulating valve 23' would be controlled by steam permitted to pass through piping 41, 42' and valve 43 to the steam chamber of the regulating valve Whenever pressure in the distributing piping exceeded a pressure of five pounds, and valve 40' need serve only as a steam trap to relieve water of condensation and need not necessarily be connected with the regulating valve at all. On the other hand, by closing valve 56' the pressure in the distributing piping would be dependent upon the pressure at which valve 40 is designed to be opened, and the regulating valve 23' under such circumstances would be controlled by the steam which would be permitted to pass through .gpiping 39 to the steam chamber of the regulatingvalve by valve 40 on any increase of pressure in the distributing piping above the pressure at which the valve 40' opens. When thus operated with valve 56 closed, valve 40' should be designed to serve as a check valve of limited checking capacity and be connected with the. regulating valve, and should also be designed to serve as a steam trap to relieve the system of water of condensation unless otherimeans is provided for such By designing valve 40' to open at a higher p're's sure than that at which valve 43' opens, the pressure in the distributing piping may be increased by closing valve 56 and may be decreased by opening valve 56.

If desired, the fiow of steam through each of the radiators 20 may be controlled by a regulating valve 57 somewhat similar to the regulating valve 23'. One suitable form of radiator regulating valve 57 is illustrated in detail in Fig. 5. It comprises an admission orifice 24 and an outlet orifice 25 for the radiator supply pipe 58 (see Fig. 4). It also comprises (see Fig. 5) a valve disk 26' which may be forcibly seated and caused to close a port 27' against the opposing effort of a resilient element 28 by any suitable thermomotive element 29'.

The resilient element 28 may, as indicated in Fig. 5, be of a form adapted to serve as a spring to oppose the expansion of the thermomotive element and also as a packing to prevent the escape of steam which passes through the joint 59 about the valve stem 31'.

The valve is normally held open either by the resilient element 28', or by the thermomotive element 29, which, when collapsed, may serve as a means of opening the valve.

On passage of steam through the valve 57 to and through the radiator to its drip connection 60, the steam will be caused to enter the steam chamber 30' of the regulating valve 5'7 through an inlet orifice 36' and then exhausted through the drip connection 60 and to atmosphere through the outlet orifice 34. The presence of steam in the chamber 30 will cause the thermomotive element 29 to be expanded and close the valve. The condensation of steam in the radiator will permit the thermomotive element 29 to be cooled and partly collapsed, thus admitting more steam to the radiator, which may thus be kept supplied with steam at substantially atmospheric pressure. The admission of steam to the radiator may be controlled at will by manually-operated valve 54'. It will be apparent, of course, that the means for controlling the fiow of steam through radiators 20' and the draining of water of condensation therefrom need not be the same for each radiator. The radiators may be supplied with steam at the constant pressure maintained in the distributing piping 21'. The radiators may be provided with any appropriate means of maintaining the radiator steam pressure at any desired pressure between atmospheric pressure and the pressure in the distributing piping, and with any appropriate means of freeing them of water of condensation.

The branch connection 41, 42 and valve 43 when used in association with the regulating valve 23 in the manner indicated in Fig. 1 and the corresponding parts of the apparatus illustrated in Fig. 4 serve as a highly satisfactory and dependable pressure-reducing means which is entirely independent of variations of pressure in the train pipe. Whether the pressure in the train pipe be twenty pounds, or one hundred and fifty pounds, a pressure of more than that at;

which the valve 43 is set to open, five pounds for example, will cause steam to be'admitted tothe steam chamber of the regulating valve and cut ofi the supply. This pressure-reducing means is en- 'rely independent of any means of adjustment to compensate for variations of pressure in the train pipe. So long as the pressure in the train pipe exceeds that at which the check valve of limited checking capacity is designed to open,

steam will be supplied at a uniform reduced pressure.

The invention is not intended to be limited to the specific forms in which it has been herein disclosed for purposes of illustration, but should be regarded as coveringv modifications and variations thereof within the scope of the appended claims.

What is claimed is:

1. A steam heating system comprising a radiator, a source or steam supply, a feed pipe connecting the radiator with aid source, a valve in the feed pipe, a thermomotive device comprising a steam chamber and associated means efiective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the part of the feed pipe between the valve and the radiator, a check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the flow or" steam from the feed pipe to the steam chamber, a return pipe connecting the exhaust outlet of the radiator with the steam chamber, and an exhaust outlet from the steam chamber.

2. A steam heating system, as defined by claim 1, having a valve in the feed pipe between the branch pipe and the radiator.

3. A steam heating system, as defined by claim 1, having a valve in the branch pipe between the check valve and the feed pipe.

4. A steam heating system comprising a radiator, a source of steam supply, a feed pipe connecting the radiator to said source, a valve in the feed pipe, a thermomotive device comprising a steam chamber and associated means efiective when heated by steam in the chamber to close the valve and hold it closed, a return pipe connecting the exhaust outlet of the radiator with the steam chamber, an exhaust outlet for the steam chamber, an open-when-cold, thermal steam trap and check valve of limited checking capacity in the return pipe to resist, to a predetermined extent, the flow of steam from the radiator to the steam chamber, a branch pipe having its ends connected with the return pipe at opposite sides of the trap so as to serve as a bypass, and a valve in the by-pass.

5. A steam heating system comprising a radiator, a source of steam supply, a feed pipe connecting the radiator with the source, a valve in the feed pipe, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the part of the feed pipe between the valve and the radiator, an exhaust outlet for the steam chamher, a return pipe connected with the radiator, an open-When-cold, thermal steam trap and check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the flow of steam from the feed pipe to the steam chamber, and a steam trap connected with the return pipe to release the water of condensation and check the flow of steam therefrom.

6. A steam heating system comprising a radiator, a source of steam supply, a feed pipe connecting the radiator with the source, a valve in the feed pipe, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the part of the feed pipe between the valve and the radiator,

,an exhaust outlet for the steam chamber, a return pipe connected with the radiator, a check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the flow of steam from the feed pipe to the steam chamber, a steam trap connected with the return pipe to release the Water of condensation and check the flow of steam therefrom, a branch return pipe connecting the steam chamber with the trapped return pipe between the radiator and the trap, and a valve in said branch return pipe.

7. A steam heating system comprising a radiator, a source of steam supply, a feed pipe connecting the radiator with said source, a valve in the feed pipe, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it, closed, an exhaust outlet from the steam chamber, a branch pipe connecting the steam chamber with the part or" the feed pipe between the valve and the radiator, a check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the iiow of steam from the feed pipe to the feed chamber, a

valve in the branch pipe between the feed pipe and the check valve, a return pipe connecting the exhaust outlet of the radiator with the steam chamber, an open-when-cold, thermal steam trap and check valve in the return pipe of a checking capacity substantially equal to that of the check valve in the branch pipe connected with the feed pipe, a branch pipe connected at its ends with parts of said return pipe at opposite sides of its check valve so as to be effective as a by-pass, and a valve in the by-pass.

8. A steam heating system comprising a source of steam supply, a distributing pipe, a valve between the distributing pipe and the source of supply, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, an exhaust outlet from the steam chamber, a branch pipe connecting the steam chamber with the admission end of the distributing pipe, an open-when-cold, thermal steam trap and check valve of limited checking capacity in the branch pipe, to resist, to a predetermined extent, the flow of steam from the distributing pipe to the steam chamber, a trap connected with the exhaust end of the distributing pipe to relieve it of Water of condensation, radiators connected with said distributing pipe, and means for automatically controlling the flow of steam through the radiators and for relieving them of water of condensation.

9. A steam heating system comprising a source of steam supply, a distributing pipe, a valve be-= tween the distributing pipe and the source of sup-, ply, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the distributing pipe, a check valve of limited checking capacity in'the branch pipe to resist, to a predetermined ex tent, the flow of steam from the distributing pipe to the steam chamber, a valve in the branch pipe between the distributing pipe and the check valve, an open-when-cold, thermal steam trap and check valve of limited checking capacity connected with the exhaust end of the distributing pipe to resist, to a predetermined extent, the flow of steam from the distributing pipe through the check valve, a connection between the steam chamber and the exhaust outlet of the check valve connected with the exhaust end of the distributing pipe, an exhaust outlet from the steam chamber, radiators connected with the distributing pipe, and means for automatically controlling the admission of steam to the respective radiators and for relieving them of water of condensation.

10. A steam heating system comprising a source of steam supply, a radiator, piping connecting said radiator with said source, a valve in said piping, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in said chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the piping between the valve and the radiator, an open-when-cold, thermal steam trap and check valve of limited checking capacityin the branch pipe to resist, to a predetermined extent, the flow of steam from the piping to the steam chamber, an exhaust outlet from the steam chamber, and means for freeing the radiator of water of condensation.

11. A steam pressure-reducing system comprising a source of steam supply, a feed pipe connected with said source, a valve in said pipe, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with a part of the feed pipe to which steam flows from said valve, an exhaust outlet from the steam chamber, and an open-when-cold, thermal steam trap and check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the flow of steam from the feed pipe to the steam chamber.

, 12. A steam pressure-reducing system, as defined by claim 11, of which the check valve is a normally open valve having as its checking means a valve disk by which the inlet orifice may be closed and a thermomotive device effective when heated to cause the disk to close the inlet orifice and hold it closed so long as the pressure against the disk is below a predetermined pressure, the disk-holding capacity of the thermomotive device being so limited that the valve may be opened when the pressure against the disk exceeds the predetermined pressure.

13. A steam distributing system comprising a distributing pipe, a source of steam supply, a valve to control the flow of steam from the source to the pipe, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the distributing pipe, an open-when-cold, thermal steam trap and check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the flow of steam from the distributing pipe to the steamchamber, and a trap to relieve the distributing pipe of Water of condensation and check the flow of steam therefrom.

14. A steam distributing system comprising a distributing pipe, a source of steam supply, a valve to control the flow of steam from the source to the pipe, a thermomotive device comprising a steam chamber and associated means eifective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the distributing pipe, a check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the flow of steam from the distributing pipe to the steam chamber, a valve in the branch pipe between the distributing pipe and the check valve, an open-When-cold, thermal steam trap and check valve of limited checking capacity connected with the exhaust end of the distributing pipe to resist, to a predetermined extent, the flow of steam therefrom, a connection between the steam chamber and the exhaust outlet of the thermal check valve, and an exhaust outlet from the steam chamber.

15. A system, as defined by claim 14, of which the checking capacity of the thermal check valve is greater than the checking capacity of the check valve in the branch pipe connected with the distributing pipe.

16. A steam heating system comprising a radiator, a source of steam supply, a feed pipe connecting the radiator with said source, a valve in the feed pipe, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, a branch pipe connecting the steam chamber with the part of the feed pipe between the valve and the radiator, a check valve of limited checking capacity in the branch pipe to resist, to a predetermined extent, the fiow of steam from the feed pipe to the steam chamber, a valve in the branch pipe between the feed pipe and the check valve, a return pipe connecting the exhaust outlet of the radiator with the steam chamber, and an open-when-cold, thermal steam trap and check valve in the return pipe of a checking capacity not less than that of the check valve in the branch pipe connected with the feed pipe.

17. A system, as defined by claim 16, of which the thermal check valve is of a definitely limited but greater checking capacity than that of the check valve in the branch pipe connected with the feed pipe.

18. A steam heating system comprising a radiator, a source of steam supply, a feed pipe connecting the radiator to said source, a valve in the feed pipe, a thermomotive device comprising a steam chamber and associated means effective when heated by steam in the chamber to close the valve and hold it closed, a return pipe connecting the exhaust outlet of the radiator with the steam chamber, an exhaust outlet for the steam chamber, and an open-when-cold, thermal steam trap and check valve of limited checking capacity in the return pipe to resist, to a predetermined extent, the flow of steam from the radiator exhaust outlet to the steam chamber.

FRANK W. DEARBORN.

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