US2307724A - Heating system - Google Patents

Description

Jan. 5, 1943. L. c. ANDERSON HEATING SYSTEM Filed March 26, 1940 headmilawrnnce. fl/mersa z Rh w WW QN Patented Jan. 5, 1943 HEATING SYSTEM Lawrence C. Anderson, Chicago, Ill., assignor to Pullman-Standard Car Manufacturing Company, Chicago, Ill., a corporation of Delaware Continuation of application Serial No. 273,139,

May 11, 1939. This application March 26,

Serial No. 326,032

4 Claims. (01. 237-6) Among the principal objects of the present invention are the following: To provide an entirely automatic sealed modulating heating system capable of maintaining uniform temperatures throughout the space to be heated, and one which will insure against freezing temperatures irrespective of the setting of the individual thermostat controlling the heating system and whether or not the main heating system is in operation; to provide a control valve for such a system which is highly eflicient in maintaining uniform temperatures irrespective of atmospheric pressure changes and is simple in construction and operation; and to provide a valve which will operate in a completely sealed system.

Other objects and advantages will become apparent as the disclosure proceeds and the description is read in conjunction with the accompanying drawing, in which Fig. 1 is a diagrammatic view of the complete heating system showing somewhat in detail the valves employed in controlling the system and showing schematically the control circuit;

Fig. 2 is a fragmentary view of a modified form of the thermostatic means for operating the control valve shown in Fig. 1.

The present invention has particular value as a heating system for railway passenger cars and the like, but its use is not limited to such installations. The system itself is shown entirely apart from any particular application of the heating arrangement, and only one embodiment is selected to disclose the invention in compliance with section 4888 of the Revised Statutes.

This is continuation of the co-pending application bearing Serial No. 273,139 filed May 11, 1939.

Referring to the figures, the heating system includes a boiler l mounted on a steam pipe line H having a primary chamber and a secondary chamber l2 and I3 respectively. In the space to be heated is a radiator 4 having fins l5, and rising from the secondary chamber l3 of the boiler I0 is a vapor riser l6 connected to the radiator M by a joint l1. A bafiie l8 extends from the mouth |9 of the joint to the upper regions so that any vapor passing through the riser I6 is discharged into the joint l1 adjacent to the top. Extending downwardly from the joint H is a return line 20 having two branches 2| and 22, both emptying into the secondary chamber l3 through a common return 23. The return line 20 has an upwardly extending screen 24 which extends Well into the joint H, as shown in Fig. 1. In branch return line 2| is a modulating heat valve and a heat protection valve 25, and in the other branch 22 of the return line is a manually operated control valve 21. A safety valve 28 is placed in the common return line 23, and its purpose is to prevent excessive temperatures or pressures from arising in the heating system.

The modulating heat valve 25 comprises a housing 29 divided into three separate chambers, 30, 3|, and 32, by partitions 33 and 34'between chambers 39 and 3|, and 3| and 32, respectively. In chamber 32, a bellows 35 is secured to the wall 36 of the housing 29. A second bellows 31 is housed in the chambers and 3| with a portion of the bellows in each chamber. The partitioned wall 33 is sealed against the bellows. Extending between bellows at its free end 38 and bellows 31 at it send 39 is a rod 40 secured to the bellows by means of plate members 4| and 42, respectively. A movable valve member 43 is carried by rod 40, and is adapted to fit into valve seat 44 in the partitioned wall 34, thus closing off passage 45 between chambers 3| and'32. A spring 46 is housed within bellows 31, and a manually operated regulating screw 41 passes through the housing 29 to serve as the stop for the spring 46. A plate 48 is inserted between the shank 49 of screw 41 and the end face of the bellows 31. The branch 2| of the return line enters chamber 3| of the valve 25 at 50, and leaves chamber 32 at 5|. Thus the flow of condensate from the radiator passes into chamber 3| at 50, through passage 45 when the movable valve member 43 opens its passage, and then leaves chamber 32 through opening 5|.

A thermostatic element generally indicated at 52 is located in the space to be heated and comprises a housing 53 in which is mounted bellows 54, secured to one face 55 of the housing 53. The housing 53 is open at one end and a cover 56 closes this opening. A bellows 51 is fastened to the cover and extends inwardly in the housing 53. An adjusting screw 59 engages the inner face of bellows 51 to regulate its degree of expansion and a compression spring 58 extends between bellows 51 and the end of housing 53. This spring urges the bellows into a contracted position opposing the force exerted by the screw 59 and resisting any tendency for the bellows to expand due to increases in pressure inside bellows 51. A wear plate 58' is inserted between the spring 58 and bellows 51.

Extending between the thermostatic element 52 and the modulating valve 25 is a tube 60 communicating with the interiors of bellows 54 and 35, and a cylindrical tube BI is positioned inside bellows 35 over the end of tube 68.

Some suitable operating medium such as light oil fills bellows 54 and 35 and tube 68 to impart movement to valve 43 in response to the requirements of the thermostat 52. This medium is preferably a liquid having a low freezing point so that the tube 68 may be placed underneath the car without danger of freezing the liquid in cold weather. Liquid also has the advantage over a gas because there is no expansion or contraction of the medium due tothe temperature changes to which it will be exposed under normal operating conditions.

The heat protection thermostat 26 includes a base 62 supporting a housing 63, which is sealed to the base. An electromagnetic coil 64 is mounted in the housing 63 between plate members 65 and 66, and a spring 61 is placed between the plate 66 and the top of the housing 63. When the unit is assembled, this spring holds the electromagnet in place.

A movable valve member 61 operates inside the coil 64 and an armature 68 is secured to the valve member 61. A sleeve 68 of non-magnetic material is inserted between the armature 68 and the magnetic coil 64. Extending through the base 62 of the valve 26 is a passage 18, and the movable valve member 61 moves in and out of the valve seat H to close and open the passage through the base 62.

Manually controlled valve 211 includes a base 12, to which is secured a housing 13. A permanent magnet 14 operates in the housing 13, and is in the form of a ring in the center of which a movable valve member 15 operates. An armature 16 of magnetic material is positioned in the field of the magnet 14, and a sleeve 11 of nonmagnetic material is positioned between the magnet 14 and the armature 16.

The movable valve member 15 closes and opens the passage 18 through the base 12 by moving in and out of the valve seat 19 in response to the position of the permanent magnet 14. A magnet supporting arm 88 extends upwardly from the magnet 14, to the end of which is secured a rod or cable 8|. The sleeve member 11 is closed across the top and is sealed to the base 12 at 82 so that the movable valve member 15 is entirely sealed from the atmosphere, thus avoiding the danger of dirt collecting on the valve seat. At the free end of the rod or cable 8I is a knob 84 for the manipulation of the manually controlled valve. A casing 85 surrounds the rod or cable 8| and is secured to the top of the housing 13, as indicated at 86.

The safety valve 28 has a passage 81 extending therethrough, and a movable valve member 88 is adapted to enter the valve seat 88 to close this passage when excessive temperatures cause a bimetallic strip 98, carrying the valve member 88, to bend toward the valve seat 88.

The thermostatic element 52 per se does not constitute any part of the present invention. There are many forms of adjustable thermostats which would be suitable in applicants device, but the one shown is simple and serves to illustrate one type.

In the operation of the system, the thermostatic element 52 is manually adjusted to operate at predetermined temperature, say, for example, 74". This is done by manipulation of the adjustment screw 58, which expands or contracts bellows 51 to compress the gas more or less within the housing 53, which, in turn,.initially sets-the 'quired between bellows position of bellows 54. A-spring I58 may be re- 51 and bellows 64 to eilect the adjustment of bellows 54 by movement of bellows 51. The entire system from the thermostatic element 52 to the shank 49 of screw 41 is placed under initial compression so that the spring 46 forces plate 48 firmly against the end of shank 48 on screw 41. This initial compression is suflicient to overcome normal atmospheric pressure changes in the chamber 38. These changes in atmospheric pressure applied against the plate 48 merely vary the distribution of the reactive forces on this plate, which opposes the force of spring 46. During normal operation of the system when heating up to 74 is required, a temperature selector switch 9| is turned to the heat" position, indicated in dotted lines at 92, thereby closing the circuit from battery 63 through the fuse 84, conductors and 96, contact plate 81, arm 92, contact plate 98, conductors 98 and I88, electromagnetic coil 64 of the heat protection valve 26, and then back to the battery through conductor'l I6 and fuse I M. The electromagnetic coil 64 is thereby energized to raise the movable valve member 61 and hold it in this raised position as long as the temperature selector switch 9| is calling for heat. Thus, the heating system is under the operation of modulating heat valve 25, which functions in the following manner: As the temperature in the space to be heated drops below 74, the gas in housing 53 of the thermostatic element 52 contracts, thereby allowing bellows 54 to expand. A light oil is contained within the bellows 54, tube 68, and bellows 35, so that, as the bellows 54 expands, the pressure on this oil is lowered, thereby permitting the force of spring 46 in the modulating heat valve 25 to force valve member 43 away from the valve seat 44 to open the passage between chambers 3| and 32, allowing the volatile liquid to flow from branch line -2I of the return line back to the secondary chamber I3 of the boiler. Steam is passing through steam line II and primary chamber I2 of theboiler so that the volatile liquid in the secondary chamber I3 contacts the heat exchange surface I82 between primary and secondary chambers I2 and I3, respectively, causing vaporization of the volatile liquid. The vapor ascends riser I6 and passes into the radiator I4 through joint I1; and, on being cooled in the radiator, condenses. The condensate flows through screen 24 in the return line 28, and the cycle is repeated. Under the initial setting of the modulating heat valve 25, the initial adjustment of that valve and the thermostatic element 52 is such that the oil pressure within bellows 54, tube 68, and bellows 35 balances the pressure of spring 46; and, when the oil pressure within bellows 54 is varied due to changes in gas pressure within housing 53, the movable valve member 43 is moved with respect to valve seat 44 until the system is again placed in a state of equilibrium. Consequently, the valve opening may be entirely closed or opened to any degree, depending upon pressure conditions within the housing 53 of the thermostatic element 52. Thus, the action of the modulating heat valve 25 is a throttling action and not a mere open-and-close action. When the temperature of the space to be heated reaches 74, gas pressure within housing 53 increases to contract bellows 54, thereby closing the passage between chambers 3I and 32 of the modulating heat valve 25.

As shown in Fig. 1, the thermostatic element 52 has a manual adjustment feature for regulating the temperature of operation the thermostat. The adjusting screw 41 is merely for adjusting the valve to initially set the system forproper operation, and for later adjusting purposes. It may be desirable, however, to use a reservoir I04 as the thermostatic element housing a volatile liquid for operating the bellows 35. In this case, a tube I05 connects the reservoir I04 with the interior of bellows 35 in the same manner as indicated in Fig. 1. Variations in temperature conditions of the space surrounding reservoir I04 changes the volume of the gas in the reservoir to alter the pressure within the bellows 35; and, in'this manner, the modulating heat valve 25 is controlled. The adjusting screw 41 is used in this instance to vary the temperature of operation of the thermostatic element I04.

It has been found that changes in atmospheric pressures can have a very decided effect on the operation of valves, and this is particularly true in railway car installations where cars may be operating at sea level or a mile or more above sea level. These variations in atmospheric pressures can affect the temperature of operation of the systems as much as four degrees, which in most instances is the diflerence between comfortable and uncomfortable temperature conditions. The present invention, however, entirely overcomes this difllculty because the valve 43 is sealed from the atmosphere and spring 46 cooperates with the adjusting screw 41 to overcome any pressure changes in chamber 30 while the thermostatic chamber 53 is sealed from the atmosphere by bellows 54 and 51. Spring 58 cooperates with adjusting screw 50 to overcome any pressure changes in bellows 51. Spring 46 is sealed in bellows 31 with the air exhausted from the bellows interior so that temperature changes in chambers 30 and 3| in no way effect the operation of valve 43. Thus, the movable valve member 43 is a floating member moving between a constant force on the one hand-namely. the spring-and a varying force on the other side-namely, a gas or oil pressure; and this gas or oil pressure varies directly with the change in temperatures surrounding the thermostatic element, whether it be of the type shown in Fig. 1 or a reservoir I04, as shown in Fig. 2. Atmospheric pressures cannot affect the forces on either side of the movable valve member 43. Consequently, the action of the heating system is the same, irrespective of the atmospheric pressure changes.

When it is no longer desired to have heatin the temperature selector switch BI is turned off; that is, it is turned to the solid line position shown at I06. Immediately the circuit to the electromagnet 64 is broken, so that the movable valve member 51 in the heat protection valve 26 drops to close the passage and prevent the flow of volatile liquid into the boiler. A heat protec tion thermostat I01 is initially set at, say, 60 or any other temperature desired as a minimum in the space to be heated. Resistors I 08 and H5 are employed in the circuit from battery 03 to the thermostat I01 so that, when the temperature is above 60, only a very small amount of current is flowing, part of which is flowing from the positive terminal +B of the battery through the resistor I08, where this current splits and fiows partly through conductor I09, thermostat I01, conductor IIO, resistor I I5, and then back to the negative terminal of the battery. The remainder flows from the resistor I08 through a relay I I I, and then back to the negative terminal through resistor 5. As long as this currentis divided as described, the relay III is too weak to close a relay switch II2; but, when the temperature drops below the circuit through thermostat I01 is opened so that all of the current from the battery passes through relay II I, thereby closing the relay switch H2. The current now passes from the positive terminal +B of the battery through conductor 05, relay switch H2, conductor I00, electromagnet 64, and then back to the negative terminal -B of the battery through conductor I I6. Thus the valve 61 is lifted to permit the volatile liquid to pass to the boiler, thereby placing the heating system into operation. of course, when the temperature of the space is below 60, the modulating heat valve 25 is open, so that the heating system is entirely under the control of the heat protection valve 26, which in turn, responds to the heat protection thermostat I01. In this manner, temperatures above freezing are always assured irrespective of whether the temperature selector switch is calling for heat.

When the temperature selector switch is calling for heat and the thermostatic element 52 is set for, say 74, a very constant temperature can be maintained; but, if the room occupant should for any reason desire a temperature higher than 74", he may bypass the volatile liquid through return line 22 by opening the manually controlled valve 21, thereby placing the heating system in manual operation.

Because of the presence of a volatile liquid in the system, it is possible for extremely high pressures to arise, and consequently the safety valve 25 is provided. As shown, this valve is responsive to the temperature of the volatile liquid, but it may be equally efiective if it responds to pressures, in which case some suitable pressure valve may be employed.

Before the closed circulating system is charged with a volatile liquid, it is first exhausted or air to a very high degree of vacuum; and then some suitable liquid, such as ethyl alcohol, is inserted and the system is sealed.

Although the present invention has a very wide range of applications, it is particularly well adapted to railway car installations because of its high degree of flexibility in operation and the uniformity of temperature which it maintains. Also, when a car is not in operation but is in the yards, it is not necessary to have temperatures of 72 or more; but it is very important to have some means of preventing freezing of the water pipes, etc., within the car. A system of this kind assures against freezing of the car.

One complete system is shown in Fig. 1 capable of heating a single zone. In the event that the heating system is applied to a plurality of zones such as a number of rooms in a railroad car, a separate complete system controlled by its own thermostatic element 52 would be placed in each room. Separate boilers may be used or one boiler with a plurality of lines branching oil may be employed.

The heating system is continuous as long as any one of the operating valves permits passage of the condensate and in normal operation the amount of condensate passing through the modulating heat valve, depends on heating requirements.

The spring 46 in the valve 25 must be strong enough to overcome any atmospheric pressure encountered because chamber 30 is not sealed and changes in atmospheric pressures in this 7 chamber should not affect the bellows 31.

The entire heating system is completely sealed from the atmosphere, and the: valve 25 is particularly well suited for such a. system.

I claim:

l. A heating system including a boiler having primary and secondary chambers in heat exchange relationship with each other, a closed circulating system including the secondary chamber, a radiator, a vapor line, and a return line, a volatile liquid in the closed system, a modulating heat valve and a heat protection valve in the return line means for maintaining the heat protection valve normally open, thermostatic means responsive to temperature conditions in the room to be heated connected directly to the modulating heat valve so that the valve positively responds to the thermostatic means, a temperature selector switch associated with the heat protection valve to hold the said valve normally open at one setting of the said switch and to close the valve at another setting of the switch for placing the heating system in or out of oporation, and a control circuit associated with the selector switch for operating the heat protection valve, said circuit maintaining the last named valve in open position at all times when the temperature selector switch is set for heating.

2. A heating system including a boiler having primary and secondary chambers in heat exchange relationship with each other, a closed circulating system including the secondary chamber, a radiator, a vapor line, and a return line, a volatile liquid in the closed system, an internally-balanced modulating heat valve having a throttling action in the return line for controlling the fiow of the volatile liquid, said valve being adapted to respond directly to temperature conditions in the space to be heated, a secondary control valve in the return line, means for alternatively maintaining said secondary valve in open position and allowing said valve to close, and thermostatic means responsive to room temperatures operatively connected to the secondary control valve, said last named thermostatic means responding to an operating temperature lower than that for the first thermostat.

3. A heating system including a boiler having primary and secondary chambers in heat exchange relationship with each other, a closed circulating system including the secondary chamber, a radiator, a vapor line, and a return line, a volatile liquid in the closed system, a primary control valve and a secondary control valve in the return ine, means for maintaining the secondary control valve normally open to permit passage of the volatile liquid through said valve, thermostatic means responsive to temperature conditions in the room to be heated operatively connected to the primary control valve, the primary valve responding to said thermostat to control the flow of volatile liquid through the return line, a temperature selector switch associated with the secondary valve to maintain said valve open at one setting of said switch and to allow said secondary valve to close at another setting of the switch, and a second thermostat operatively connected to the secondary valve for controlling same, said second thermostat responding to temperatures in said room.

4. A heating system including a boiler having primary and secondary chambers in heat exchange relationship with each other, a closed circulating system including the secondary chamher, a radiator, a vapor line, and a return line, a volatile liquid in the closed system, a primary control valve in the return line, thermostatic means responsive to temperatures in the room to be heated operatively connected to the primary valve, said valve being balanced so that it responds to slight changes in room temperatures. a secondary control valve in the return line, a thermostatic control circuit for the secondary control valve, the secondary thermostatic control circuit functioning at an operating temperature lower han that of the primary thermostat, and a temperature selector switch associated with the secondary control valve to maintain said secondary valve open at one setting of said switch and to allow said secondary valve to close at another setting 01' the switch.

LAWRENCE C. ANDERSON.

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