US2185500A

US2185500A - Heat balancer

Info

Publication number: US2185500A
Application number: US15016A
Authority: US
Inventors: Jr David N Crosthwait; Ellis G Powell
Original assignee: C A DUNHAM CO
Current assignee: C A DUNHAM Co
Priority date: 1935-04-06
Filing date: 1935-04-06
Publication date: 1940-01-02
Anticipated expiration: 1957-01-02

Description

1940' D. N. CROSTHWAIT, JR., ET AL 2,185,500

HEAT BALANCER Y Filed April 6, 1935 7 Sheets-Sheet 3 lmlen'lgrs awzzz/mm P LS r AL '7 Sheets-Sheet 4 D. N. CROSTHWAIT. JR.

HEAT BALANCER Filed April 6, 1935 Jan. 2, 1940.

Imlen'l rs 212W Masai/01f Z5221: 7flm/e/Z dim 1940- D. N. CROSTHWAIT. JR., ET AL 2,185,500

HEAT BALANCER Filed April 6, '1955 7 Sheets-Sheet 5 Jan. 2, 1940. n. N. CROSTHWAIT, JR.. ET AL 2,185,500

HEAT BALANCER Filed April 6, 1935 7 Sheets-Sheet 7 45 portioning motor.

Patented Jan. 2 1940 UNITED STATES 4 PATENT OFFICE HEAT BALANCER Application April 6, 1935, Serial No. 15,016

11 Claims. (c1. 236-91) that the temperature setting maintained by said' devices may be adjusted at will or in accordance with the heat requirements.

In ordinary practice each temperature regulator may have a means of adjustment so that it may be set for the desired predetermined temperature which the regulator is to maintain. In recent years it has become more desirable to locate the operating portions of control equipment at a central location, and it is frequently desirable to provide means located at this central point so that the setting of a regulator remotely located may be changed as desired. Since the distances between the difierent portions of the control equipment may be considerable, the interlocking controls can best be accomplished electrically. According to the principles of the present invention, the valve or other mechanism which controls the flow of heating medium to abe adjusted, so that the thermostatic device will control the proportioning motor to maintain a selected predetermined temperature by means of electrically operated mechanism partially positioned at the heat balancer and partially positioned on a control panel which may be located remote from both the heat balancer and the pro- This control mechanism on the panel may also be automatically controlled from thermostats located at points remote both from the panel and the heat balancer and motor. However, the general control is centralized on 50 this control panel so that any selected one of a plurality of difierent methods of operation may be obtained from this one central point.

The heat balancer. briefly described, comprises a control resistance the setting of which is var-.

. ied under the conjoint influence of a thermostatic device and an opposing spring. The force. exerted by the spring is automatically adjusted by means of a proportioning motor which is electrically controlled from the remote control panel, either manually or automatically from a thermostat located at any desired point.

The principal object of this invention is to provide an improved heat control mechanism of the type briefly described hereinabove and disclosed more in detail in the specification which follows.

Another object is to provide an improved regulator which may be set to maintain a given predetermined condition from a point greatly 1 remote from the regulator.

Another object is to provide a temperature regulator which operates a remote device through electrical connections and which itself may be set for various temperatures electrically from aremote point. 20

Another object is to provide an improved heat balancer.

Another object is to provide improved means for regulating the flow of heating medium or other fluid in response to variations in tempera- 25 ture at one or a plurality of difierent points, the temperature to be maintained being regulatable from still a different point, for example the interior surface of an outside wall of the space being heated.

Another object is to provide a temperature regulator including means for automatically controlling an exhausting pump.

Another object is to provide an improved temperature regulator including cooperating propor- 5 tioning motors.

Other objects and advantages of this invention will be more apparent'from the following detailed description of certain approved forms of apparatus designed and operating according to 40 the principles of this-invention.

In the accompanying drawings:

Fig. 1 is a diagrammatic elevation of a heating system with the improved regulating apparatus applied thereto.

Fig. 2 is an elevation of the heat balancer unit, with parts broken away.

Fig. 3 is a vertical section taken substantially on the line 3-3 of Fig. 2.

Figs.'4 and 5 are wiring diagrams of one complete heat-regulating system. The control panel at the right of Fig. 4 is repeated at the left of Fig. 5, otherwise these views are continuations of the same wiring diagram.

Fig. 6 is a simplified wiring diagram illustrat- I or processing systems.

, ments can be made.

ing the proportioning motor system for controlling the heat balancer from a remote point.

Fig. '7 is a simplified wiring diagram illustrating the proportioning motor system for operating the flow-control valve.

Fig. 8 is a wiring diagram, similar to Figs. 4 and 5, but illustrating the cooperating use of a plurality of room thermostats.

Fig. 9 is a diagrammatic elevation showing the temperature control system applied to a vacuum evaporator.

Reference will first be made to Fig. 1 which shows, by way of illustration, the improved regulating system as applied to a heating system of the Dunham differential type. It will be understood that this improved regulating mechanism can be used with other types of heating Steam from the boiler or generator I is delivered through pipe 2 and reducing valve 3 into the main supply pipe 4. Steam at the reduced pressure in pipe 4 flows. through risers 5 into a plurality of separate radiators, two of which are indicated at 6 and 6' respectively. Non-condensable gases and condensates are drawn out through steam traps I and pipes 8 into the main return pipe 9 and. delivered into the accumulator tank II). The gases and condensate are drawn from tank in by means of the exhausting apparatus indicated generally at II and including a pump l2 driven by motor l3, the gases being vented and the condensate returned to generator I. The motor l3 of exhausting apparatus II is started and stopped as conditions require by means of a differential-pressure controller 14 so that the pressure in return line 9 will always be maintained lower than the pressure in supply pipe 4 to insure the evacuation of non-condensable gases and condensate from the radiators 6. By proportionately opening or closing the main flow valve 3, the flow of steam admitted to supply pipe 4 may be varied so as to control the pressure and temperature of the steam in the radiators to maintain any desired temperature in the enclosure that is being heated. The temperaturecontrolling apparatus forming the particular subject matter of this invention is adapted to automatically regulate the setting of valve 3 (and at times control the operation of pump [2) so as to maintain a predetermined selected temperature within the enclosure.

At A is indicated a proportioning motor apparatus adapted, through crank l5 or its equivalent, to partially open or shut the valve 3 in accordance with the electrical control exerted from a remote point as hereinafter disclosed. At B is indicated the improved heat balancer which is controlled in part by the thermostatic device C which comprises a temperature responsive element positioned in one of the radiators 6, preferably a radiator rather remote from the source of steam supply, and connected through the small pipe IS with an operating element in heat-balancer B, as hereinafter explained. At D is indicated the main control panel positioned in an accessible location and from which all of the principal manual adjust- The motor A and cooperating relay panel H are connected with control panel D through the groups of wires or cables I! and 11'. Heat balancer B is connected with the control panel through wires I8. At E and E are indicated two of a group of thermostats, located at suitable selected points within the enclosure, and connected through cables I9 with the terminal box 20, in turn connected through cable 2| with control panel D. At F is indicated a thermostat preferably positioned against the inner surface of an outside wall of the building so that it will respond to changes in the rate of heat loss from the building. This rate of heat loss is determined by the lag in change of inside wall surface temperature behind the change of exterior wall surface temperature in response to changes in the outside temperature. Thermostat F is connected with control panel D through cable 22. The controller G for the pump motor I3 is connected with the control panel through wires 23 and with the heat balancer through wires 24. The heat balancer B is preferably positioned in the vicinity of radiator 6 so as to minimize the length of pipe 16 leading to the thermostat C in the radiator, but all of the other elements of the control system may be positioned wherever desired, and remote from one another, since they are connected through trol the motor A so as to adjust valve 3 to maintain a desired steam flow in accordance with variations from a predetermined temperature in the heating medium in radiator B. This predetermined temperature for which the heat balancer is set may be adjusted from the control panel D either manually, or automatically in response to temperature changes recorded by the wall thermostat F. The average of the room temperatures registered by the thermostats E, E, etc., may also be combined (through control panel D) with the temperature variations registered by thermostat C to determine the temperature in response to which the heat balancer B controls motor A. In any case the thermostatic control is in part at least in response to changes in the temperature of the heating medium within the radiators, thus establishing an upper and lower limit control minimizing overshooting and undershooting, and the waste of heat due to abnormal and tem porary conditions such as the opening of windows. Motor A may also be controlled manually from the control panel D.

Before describing the elements of the heat balancer system in detail, we will first refer to the wiring diagrams in Fig. 6 and 7 which illustrate the electrical principles involved in this system. Fig. 6 illustrates the proportioning-motor system through which the heat balancer is automatically adjusted. The high

potential mains

25 and 26 are connected through cut-out switch 21 with the terminals of the primary coil 28, of a transformer T. The terminals of the secondary 29 of transformer T are connected by

wires

30 and 3| with the respective terminals of a solenoid coil 32. The proportioning motor M com prises a pair of connected rotors 33 and 34. The stator coils 35 and 36 for the rotors 33 and 34 respectively are connected in series through wire 31, and their outer terminals are connected through

limit switches

38 and 39 with the

power lines

30 and 3| respectively. stators 35 and 36 tend to cause the rotors 33 and 34 to turn in opposite directions, and when the same current flows through both stators the torques exerted by the two opposed rotor elements will be equal and the motor will remain at rest. Wire 40 extends from wire '31 between the two stators to the movable switch arm 4| adapted to contact alternatively with the two fixed

contacts

42 and 43. Switch arm 4| is connected through stem 44 with the core 45 of solenoid 32, and when both halves of this solenoid are equally energized the core 45 will be centered within the solenoid coil and switch arm 4| will be out of contact with both fixed

contacts

42 and 43. A balancing resistance R1 has its terminals 46 and 47 connected through wires 48 and 49 and protective resistances 50 and 5| with the respective terminals of the solenoid coil 32. A pivoted contact arm 52 engages at its free end with the balancing resistance R1 so as to divide this resistance into two effective portions 1" and r. The contact arm 52 is connected through wire 53 with a contact 54 midway the ends of solenoid coil 32. Suitable means (not here shown) is provided for slowly swinging contact 52 about its axis as the motor M rotates in one direction or the other so as to change the values of the two resistances 1' and r. All of the parts thus far described form part of the heat balancer unit B.

On the control panel D is positioned an adjusting resistance R2 which may be in'all respects the same as the balancing resistance R1 already described except that the movable arm 55 of this resistance-R1 is to be adjusted manually so as to change the respective values of the two re sistances r and 1''. Wires 56 and 51 extend from wires 48 and 49 to the respective swinging arms 58 and 59 of a double-throw switch S1 also positioned on control panel D. Wires 60 and BI lead from the terminals of resistance Rate the pair of fixed

contacts

62 and 63 of the switch S1. The other pair of fixed contacts 64 and 65 of the switch S1 are connected by

wires

66 and 61 with the terminals of a third adjustable resistance R3 forming part of the thermostatic device F. The movable contact arm 68 is adjusted longitudinally of the resistance member by the expansion or contraction of the thermostatic member 69. The

movable contact arms

68 and 55 of the resistances R3 and R2 respectively are connected through wires 16 and H with wire 53 leading to the central contact of solenoid coil 32.

With switch S1 in the position shown in Fig. 6, it will be noted that each of the resistances R1 and R2 is connected in parallel, through protective resistances 50 and 5|, across the terminals of solenoid 32. Also each of the halves r of the two resistances is connected in parallel with onehalf s of the solenoid coil, and the other two halves r' of the two resistances are connected in parallel with the other half 8 of the solenoid coil. With-the movable contact arms 52 and 55 of the two resistances in the mid -positions shown, the resistances T will equal the resistances r and therefore the same currents will flow through each of the two portions s and s of the solenoid coil and the core 45 will be drawn to the central position shown in the drawings. Let us assume now that the movable contact member 55 of adjustable resistance R2 is moved a selected distance in one direction, for example clockwise. The section r of this resistance will now be diminished and the section T will be increased. Consequently the current flowing through the portion 1 of resistance R2 will be increased, and

the current flowing through section s of solenoid,

32 will be decreased while the current flowing through section s will be increased. This will result in drawing the core 45 downwardly (as seen in Fig. 6) so as to bring movable contact 4| into engagement with fixed contact 43. This will complete a circuit from wire 3| through a few end turns of the solenoid coil, wire 12, fixed contact 43, movable contact 4|, and wire 40, which will short-circuit the stator 36 so that a greatly increased current will flow through stator 35 (with respect to the current in stator 36) and the torque of rotor 33 will overcome the opposing torque of rotor 34 and-the motor M will begin to rotate in a certain direction. This rotation will not only move a portion of the heat balancer mechanism (as hereinafter described) but will also swing the arm 52 of balancing resistance R1 in a counterclockwise direction so as to increase the resistance section 1' and decrease the resistance section r of resistance R1. As a result the total resistance in parallel with solenoid section s will be gradually increased and the resistances parallel with solenoid section 8 will be decreased. This movement will continue until the total resistances in the two halves of the parallel circuits are again balanced, whereupon the currents flowing in the two halves of the solenoid will again be balanced and the core 45 will again be drawn to the mid-position shown in the drawings thus moving switch arm 4| out of engagement with fixed contact 43. The currents flowing in the two stators 35 and 36 will again be balanced and the motor will stop It will be noted that the motor M will rotate for a total distance proportionate to the amount that adjusting resistance R2 has been thrown out of balance, before the circuits are again balanced by the movement of balancing resistance R1.

If the arm 55 of manually adjustable resistance R2 is moved in the opposite or counter-clockwise direction, the circuits will be unbalanced in a reverse manner so that movable switch arm 4| will be moved into contact with fixed contact 42 and stator 35 will be short-circuited through the 'circuit from wire 30 through a few end turns of coil 32, wire 13, fixed contact 42, movable contact 4|, and wire 40. As a result the proportionate current flow through stator 36 will be increased and rotor 34 will cause rotation of motor M in a reverse direction. This will cause arm 52 of balancing resistance R1 to be swung slowly in a clockwise direction until the circuits are again balanced. It will now be apparent that the direction and amplitude of movement of the parts moved by motor M will be proportionately determined by the direction and amplitude of move ment given manually to the arm 55 of resistance R2. In order to limit the rotation of motor M in either direction, suitable means are provided for'opening one or the other of the limit switches 38 or 39 when this limit is reached so as to stop the motor. This limiting mechanism will not normally be brought into action and need not be further considered here.

If switch S1 on the control panel D is thrown to its other position so as to bring the movable contacts 58 and 59 into engagement with the fixed contacts 64 and 65, the thermostat controlled resistance Ra will be substituted in the circuits previously described for the manually adjustable resistance R2. The functioning of the mechanism will be exactly the same as described hereinabove except for the fact that the motor M is now controlled by the movements of contact arm 68 of resistance Rs in response to temperature changes which a'fiect the'thermostatic element 69.

The simplified diagram shown in Fig. 7 illustrates a similar circuit system for controlling the proportioning motor M which operates the supply valve 3 (Fig. 1) or the other similar mechanism to be controlled. Motor M comprises the two rotors 14 and 15 and their respective stators 16 and 11, this motor operating in all respects the same as the motor M previously described. The high potential power lines 18 and 19, provided with main cut-out switch 80, lead respectively to the terminals of primary coil SI of the transformer T. The secondary 82 of this transformer furnishes low potential current through wires 83 and 04 to the terminals of balanced solenoid 85, and through the parallel circuits of resistances R4, R5, and R6 in much the same manner as was described in connection with Fig. 6. Balancing resistance R4 is adjusted by the rotation of motor M. The adjustable resistance R5, adapted to be manually controlled, is positioned on the control panel D. The adjustable resistance R6 is a part of the heat balancer B and is thermostatically adjusted as will be hereinafter explained. This resistance Rs differs from the other resistances hereinabove disclosed in that it consists of two

separate resistances

86 and 81 independently contacted by the two simultaneously swinging

arms

88 and 99. The

arms

88 and 89 are moved by the balanced thermostatic mechanism in the heat balancer as will be hereinafter explained. The two simultaneously moving

arms

89 and 89 are connected together by the wire 90 which leads eventually to the central point of solenoid 85, and this resistance Re operates in all respects the same as the other resistances R1 to R5 inclusive. It is made in two sections so that it may be connected in series with other similar thermostats, as will be hereinafter explained.

The solenoid 85 will be unbalanced or balanced under the control of the several resistances R4, R5 and R6 in much the same manner as was described for the'solenoid 32 in Fig. '6. When the core SI of solenoid 85 is shifted in one direction it will bring movable contact 92 into engagement with fixed contact 93 thereby completing a circuit which short-circuits one-half of a second balanced solenoid 94, this circuit being as follows: From power line 83 through a few end turns of solenoid coil 85,-wire 95, fixed contact 93, movable contact 92, wire 96, protective resistance 91, and wire 98 to a terminal midway the length of coil 94. When solenoid 85 is unbalanced in the other direction, arm 92 will be swung into engagement with a second fixed contact 99 thereby completing a circuit from wire 84 through a few end turns of coil 85, wire I00, fixed contact 99, swinging arm 92, wire 96, resistance 91, and wire 98, thus short-circuiting the other half of balanced solenoid 94. As one half or the other of solenoid 94 is short-circuited, the core I.0I of this solenoid will be shifted in one direction or the other to swing arm I02 into engagement with either of the fixed contacts I03 or I04. When arm I02 is moved into engagement wtih contact I03, a high potential circuit for energizing the stator 16 of motor M will be completed as follows: From power main 18 through wire I05, swinging arm I02, contact I03, wire I06, stator 16, and wire I01 to the other power line 19. If-arm I02 is moved into engagement with contact I04 a similar .cir-

cuit for energizing the'other motor stator 11 willthe other power line 19. In this manner the motor M will rotate in one direction or the other to open or close the valve 3 an amount proportionate to the unbalancing movement of the resistances R5 or Re. In the more detailed description of the complete regulating systems which follow, the reference characters used on Figs. 6 and 7 will be repeated, as far as practicable, to indicate corresponding parts so that these elements need not be described again.

Referring now to the more complete wiring diagram as shown in Figs. 4 and 5, the portion shown at the left of Fig. 4 is substantially the same as has already been described in connection with Fig. '7. The transformer, relay and balanced solenoid are positioned on a separate panel H, whereas the proportioning motor M and balancing resistance R4 are positioned in the assembly A adjacent the valve to be operated. (See also Fig. 1.) Power is supplied to the panel H from the outside lines I09 and I I0 through the fused switch Ill. The wires H2, H3 and H4 (indicated as cable I1 on Fig. 1) lead from relay panel H to the terminals H5, I I6 and I I1 respectively on control panel D. Jumper wire H8 and wire II9 lead from terminal II6 to the swinging contact member of manually operated resistance R5. Terminals H5 and H1 are connected through wires I20 and HI respectively with the swinging contact arms I22 and I23 of switch 8:. When this switch is thrown to its upper position, these arms will engage the fixed contacts I24 and 925 which are connected with the terminals of resistance R5. With the switch S2 in this position, the valve may be set manually from the control board D by adjusting the resistance R5. When switch S2 is thrown to its lower position so that the swinging arms I22 and I23 engage respectively with the flxed contacts I26 and I21, the valve is adjusted automatically from the heat balancer B. Contacts I26 and I21 are connected through wires I28 and I29 respectively with the panel terminals I30 and I3I. Panel terminalylfl is connected through jumpers I33 and H8 with terminal III. Wires I34, I35 and I36 lead respectively from the panel terminals H32, I30 and I3I to the terminal I31, I38 and I39 on heat balancer B (see Fig. 5). These wires are indicated on Fig. 1 as the cable I8.

The heat balancer B will now be described referring more particularly to Figs. 2, 3 and 5. The actual mechanism as shown in Figs. 2 and 3 will first be described. The thermostat C (see also Fig. 1) comprises a protective casing I40 inserted in one of the radiators 6 and anchored thereto at I. Within casing I40 is a hollow member I42 containing a quantity of heat-responsive fluid and connected through small pipe I43, enclosed in the protective-casing I6, to the interior of a housing I44 on panel B. The lower wall of chamber I45 within casing I44 is formed by a bellows diaphragm I46 with which is connected plunger I41. As the temperature of the steam or other heating medium within radiator 6 rises, the fluid within member I 42 of the thermostat, tube I43 and chamber I45 will expand and force the diaphragm I46 and plunger I41 downwardly. The pointed lower end I 48 of plunger I41 engages the upper surface of a lever I49 pivoted at I50 on the panel B. The upper end of a compression spring I5I is seated on a plate I52 having a pointed projection I53 which engages the lower surface of lever I49 opposite the plunger I41. The lower end of spring I5I contact I04, wire I08, stator 11, and wire I01 to encircles a centering member I54 carried by the Fig. 7).

spring support I55 pivoted on pin I56 extending through the upper arms of yoke member I51. The guide pin I58 carried by the fixed bracket I59 extends'upwardly through a central opening in spring support I55. The lower arms of yoke member I51 carry a pivot pin I68 on which are also pivoted theguide links I6I, the outer ends of which are pivoted at I62 in stationary bracket I59. The central portion of 'pin I68 also carries a roller I63 which rests on the cam or eccentric I64 fixed on shaft I65 which is driven by the proportioning motor M. i

It will now be apparent that the pressure developed by the expansion of the thermostatic fluid in thermostat 0 tends to force lever I49 downwardly whereas spring I5I exerts an up ward force opposing this movement of the lever. The, compression of spring I5I may be varied by rotating the eccentric I64 and thus lifting or lowering the spring support I55, and in this way the efiect any change in temperature to which thermostat C is subjected exerts on lever I 49 may be adjusted by properly'positioning the eccentric I64 through the action of proportioning motor M. On the outer end of shaft I65 is a cylindrical calibrated dial I66 on which stationary pointer I81 indicates whether the elements are so positioned as to raise or lower the temperature.

The free end of lever I49 is forked at I68 to engage pin I69 on lever I III pivoted at I1I Lever \I18 carries the two

movable contact arms

88 and 89 which engage the

separate resistances

86 and 81 of the adjusting resistance Rs (see also Still referring to Fig. 2, the movable lever I49 carries the adjustable screw I12 which operates the micro-switch I13, which in turn controls the solenoid contactor indicated generally at I 14. This contactor comprises a pair of separate solenoids I15 and I16 adapted to alternatively draw up the cores I11 and I18 respectively, these cores being respectively connected with the opposite ends of pivoted lever I19. Spring I88 is so mounted that when one core is drawn upwardly so as to swing lever I19 past its center, the spring I88 will snap the assembly to one extreme position and hold it there i'hus engaging .one set of contacts and disengaging another as Willlater be explained in connection with Fig. 5.

A limit switch mechanism indicated generally at I8I in Figs. 2 and 3 will be best understood if considered in connection with the diagrammatic showing in Fig. 5. This switch comprises a contact-carryin arm I82 normally moved up by spring I83 so as to bridge a pair of fixed contacts I84 and I85. When eccentric I62 is swung to its extreme down position as indicated in Fig. 3 it will engage an adjustable member I86 carried by arm I82 so as toswing'the arm downwardly and bridge a second pair of fixed contacts I81 and I88, at the same time breaking the circuit between-contacts I84 and I85. The panel B (Fig. 2) also carries the transformer T and a and I94 to the cut-out switch I89.

pair of cut-out switches I89 and I98. Switch I89 controls the power connections to the heat bal:

of transformer T. Wires 56, 51 and H (included in cable I8 of Fig. 1) extend from the control panel D to the terminals I91, I98 and I99 respectively on heat balancer B. From these terminals wires 288, 28I and 282 lead to the balanced solenoid 32, and this solenoid, the proportioning motor M, and balancing resistance R1 are wired and operate substantially as already described in connection with Fig. 6. Terminal I31 is connected through wire 283 with the movable contact arm 88 engagin resistance 86. Terminal I31 is also connected through wires 284 and 285, limit switch contacts I89, I82 and I85, andwires 286 and 288 to the-movable contact arm 89 which engages the portion 81 of adjusting resistance Re. The panel board terminals I38 and I39 are connected through wires 289 and 2I8 with the outer ends of the two

resistance portions

86 and 81 respectively. It will thus be seen that (when switch S2 on the panel board D is thrown to its lower position) the adjustable resistance Rs will be connected in parallel with the balanced solenoid on panel board H so that the valve-setting motor M will be automatically controlled from thermostat C and the adjustable balancing spring I5I.

It will be noted that when the temperature of the heating medium in the radiator rises lever I49 will be swung downwardly and the

movable contacts

88 and 89 will be swung upwardly soas to decrease resistance 86 and increase resistance 81, and this acts eventually to close, or partially close, valve 3 and cut down the flow of heating medium to the radiator. 0n the other hand, as the temperature in the radiator is lowered, lever I49 will rise under'the influence of spring I5I and

contacts

88 and 89 will be moved downwardly to increase the resistance 86 and decrease the resistance 81 with the result that the valve willbe opened to increase the flow of heating medium to the radiator. As eccentric m is turned upwardly by proportioning motor M, the compression of spring I5I will be increased and a higher temperature in the radiators will be required to force lever I49 downwardly in opposition to the I spring and thus cut down the flow of steam. As

a result a higher temperature will be maintained a in the radiators. If eccentric I64 is swung to its completely lowered position (as shown in Fig. 3) it will engage the contact screw I86 and swing down the contact arm I82 against the resistance of spring I83 thus opening the circuit between contacts I84 and I85 and closing the circuit between contacts I81 and I 88. The upper resistance member 86 will now be completely short-circuited through the following circuit: From terminal I31 through wires 284 and 2I I, switch contacts I88, I82 and I81, and wire 2I2 to terminal I38. At the same time the circuit through resistance 81 will be broken between the contacts I84 and I85. As a result the valve will be moved to completely closed position. This-shutting of the valve may be obtained in this manner even before the lever I49 has been swung under the influence of thermostat C to close the valve.

It is sometimes desirable, in order to economize power, to stop the exhausting mechanism II by stopping pump-motor I3 when a desired temperature has been reached and valve 3 is closed or partially closed to cut down the flow of heating medium. At this time the operating lever I49 will be swung down so as to engage plunger 2I3 of the micro-switch I13 and move contact 2 l4 of this switch into engagement with the fixed contact 2I5. Normally contact 2I4 will be in the upper position in engagement with fixed contact 2I6. Wires 2I1 and 2I8 extend from the controller G for the pump motor I3 through cut-out switch I90 to the fixed contacts 2I9 and 220 of the solenoid contactor I14. When these fixed contacts are bridged by the movable contact 22I motor I3 is permitted to operate under the control of the difierential controller I4. When contact 22I is moved up out of engagement with contacts 2I9 and 220 so as to break this circuit the motor I3 cannot operate. A second movable contact 222 is adapted to bridge a second pair of fixed contacts 223 and 224. A third movable contact 225 is adapted to bridge a pair of fixed

contacts

228 and 221. The three movable contacts 22I, 222 and 225 are simultaneously actuated by the solenoid contactor I14 so that when the circuit through MI is closed the circuit through 222 will also be closed but the circuit through 225 will be open. When lever I49 is moved down, as already described, so as to shut off the heat it will close contacts 2| 4 and 2I5 of the micro-switch and a circuit will be completed as follows: From one side of power switch I89 through wire 228, contacts 2I4 and 2I5 of the micro-switch, wire 229, contacts 224, 222 and 223, wire 230, solenoid coil I16, and wire 23I to the other side of power switch I89. As a result core I18 will be drawn up so as to elevate the several contacts 22 I, 222 and 225. This will break the control circuit for pump motor I3 so that this motor will stop. At the same time the solenoid energizing circuit for solenoid I16 as just described will be broken between contacts 223 and 224, but the solenoid cores will be held in the position to which they have been moved by the spring I88 (see Fig. 2). When lever I49 is again raised and the valve is open, contact 2 of the micro-switch will move back into engagement with contact 2I6 and a second actuating circuit will be completed as follows: From power switch I89 through wire 228, switch contacts 2H and 2I6, wire 232,

contacts

221, 225

and 226, wire 233, solenoid I15, and wire 23I back to the power switch I89. Solenoids I15 will now be energized to draw up core I11 and return the parts to the positions shown in Fig. 5, whereupon the motor I3 will again be permitted to operate under control of the differential controller I4.

The operation of the system as disclosed in Figs. 4 and 5 will now be briefly summarized.

Assuming that switch S2 on control panel D is thrown to its upper position, the setting of the flow control valve 3 is effected entirely by manual adjustment of the resistance R5, and the heat balancer and thermostatic equipment has no influence over the valve setting. However, if switch S2 is thrown to its lower position the valve setting will now be controlled by thermostat C in the radiator through heat balancer B. If a sufiiciently high temperature is reached in the radiators the valve 3 will be substantially closed and the pump motor I3 will be stopped. If switchsl on the control panel D is thrown to its upper position, the temperature that is automatically maintained in the radiators can be selected automatically by manually adjusting the resistance R2 on the control panel. If switch S1 is thrown to its lower position, this I that the heat balancer will be inefifective.

temperature that is maintained in the radiators will be varied in response to the temperature fluctuations to which thermostat F is subjected. If the temperature at thermostat F is lowered. indicating an increased heat loss from the building, it is desirable that a higher temperature be maintained in the radiators, and the apparatus functions automatically to bring about this adjustment. Conversely, if the heat loss is lowered as a result of a higher outside temperature, thermostat F will act to lower the temperature that is automatically maintained in the radiators.

In the somewhat more complicated system disclosed in Fig. 8 a plurality of room thermostats E, E', E" and E', are added to the system and the valve setting is controlled by the conjoint action of these thermostats and the heat balancer B. The valve is adjusted in accordance with the average of the temperatures registered by the several room thermostats E and the radiator thermostat C. There is no change in the structure or operation of the assemblies A,

shunt circuits controlled by limit switch I8I (Fig.-

5) are omitted. Only this much of the structure is illustrated in Fig. 8 and it will be understood that the remainder of the heat balancer assembly is the same as shown in Fig.5. A third switch S3 has been added to the control panel D. This switch may be swung upwardly into engagement with the fixed contacts 235 and 236 or downwardly into engagement with the fixed

contacts

231 and 238.

Each of the room thermostats E includes a variable resistance assembly similar in all respects to the resistance Rs in the heat balancer. The two movable arms of each thermostat assembly are adjusted simultaneously in one direction or the other by the heat-responsive element of the thermostat. It will be noted that all of the resistance elements 1' at one side of each of the several thermostats E are connected in series (through terminal box 20) between

wires

239 and 240. Also, all of the resistance elements r at the other side of each of the thermostats are connected in series in a similar manner between wires 240 and 2.

The system as disclosed in Fig. 8 is capable of a plurality of different methods of operation. If switch S2 is thrown to its upper position (no matter what the position of switches S3 and S1 may be) the valve operating motor M can only be operated manually from the adjustable resistance R5. For any "of the automatic operations switch S2 is thrown to its lower position. If switch S3 is thrown to its upper position in engagement with contacts 235 and 236, the wires 239. 240 and 2 leading from the group of thermostats E will be connected respectively (through intermediate wires and contacts on control panel D) With the Wires H2, H3 and H4 leading to the balanced solenoid which controls the valve-operating motor M. At the sametime the elements of the resistance R6 of the heat balancer B will be short-circuited so Under these conditions the valve opening will be controlled solely by variations in the average temperature recorded by the several thermostats E, E, etc.

Now if switch S3 is thrown to its lower position in engagement with fixed

contacts

231 and 238 the resistance elements of the group of thermostats E will be short-circuited so that these thermostats will be ineffective. At this time wires H2 and IN leading from the extremities of balanced solenoid 85 will be connected respectively with wires I35 and I36 leading to the extremities of the resistance elements of resistance R6 of the heat balancer. Wire H3 leading from the middle of solenoid 85 will be connected with both of the wires I34 and 234 leading to the movable contact arms of resistance R6. Under these conditions the valve will be controlled entirely from the heat balancer as described in connection with Figs. 4 and 5.

Now let us suppose that switch S3 is moved to open position so as to not engage with either set of

contacts

235, 236 or 231, 238. At this time resistance element 86 of the heat balancer resistance Re will be connected in series with the several resistances r of the group of thermostats E, and the resistance element 81 of the heat balancer will be connected in series with the several resistances r of the thermostats E. The mid-wire leading'to balanced solenoid 85 will be connected through jumper 242 on the panel board D with wire 240 connected between the two groups of series-connected resistances. As a result the valve will be controlled in response to variations in the average temperatures registered by the several thermostats E and the temperature of the heating medium in the radiators as registered by thermostat C. Under any of these methods of operation in which the heat balancer B is involved, the predetermined temperature to be maintained in the radiators can be adjusted, either manually from resistance R2 if the switch S1 is'thrown to its upper position, or automatically from thermostat F if switch S1 is thrown to its lower position.

It should now be apparent that in any of these various methods of operation the temperature maintained in the radiators is controlled, through the heat-balancer, directly by the thermostatic device C positioned in one of the radiators, this control being modified manually or by one or more other thermostatic devices positioned to respond to temperature changes at any selected 10- cations. A single thermostat such as-F may be located, as already described, so as to respond to heat losses due to changes in outside temperature, or this thermostat may be located within some selected part of the enclosure to respond to temperature changes in the space that is being heated. Or, if preferred, or found desirable, a plurality of thermostats may be used to respond to the average of these various temperatures. In any case the heat-balancer serves to cause complete distribution of steam, particularly in extreme mild weather, when the room thermostat may be satisfied and remote radiators would fail to receive sufficient steam if the heat-balancer were not used. room temperature behind change in rate of steam flow, that is it minimizes the tendency to adjust therate of heat supply too far or too late to properly compensate for changes in room temperature. It establishes a maximum rate of supply, which maximum is varied in accordance with changes in the normal prevailing rate of heat loss, but which maximum is not exceeded in response to abnormal and fleeting heat deof any inside thermostat.

It also compensates for lag of mands resulting from the opening of windows or doors or other temporary conditions. The heat balancer automatically adjusts the valve for fluctuation in initial steam pressure at the inlet to the control valve. Also, as a result of the'amount of heat required to raise the temperature of the heating system one degree being different from the amount of heat which is required to raise the room temperature one degree, there is a tendency for these two temperatures to get out of step, and the heat-balancer tends to anticipate this variation in an inverse direction.

These advantages will be more apparent if the completely automatic system involving the use of heat-balancer thermostat C, wall-temperature thermostat F, and one or more room thermostats E is contrasted with the ordinary system controlled directly by a room thermostat. These room thermostats have a very small operating range, not over 2 or 3 degrees, and any temporary fluctuation in room temperature as caused, for example, by an open window or door will so affect this thermostat as to cause a complete opening of the control valve producing a maximum steam flow to the radiators, thus greatly exceeding the actual need for heat since the radiators are already giving out sufiicient heat to offset the normal heat losses. As a result the heat output will be so increased by the time the temperature rise in the enclosure is effective to operate the inside thermostats that the proper inside temperature will be greatly exceeded. The present system so dampens or restricts the control of the room thermostats as to' prevent this overshooting. The control valve is primarily set by the radiator thermostat C of the heat-balancer to maintain a temperature in the radiators just sufficient to ofiset normal maximum heat losses. This control is adjusted by the wall thermostat F usually located to be actuated by the wall having the maximum heat loss so that the normal valve setting thus maintained will be somewhat increased or decreased in accordance with variations in this rate of heat loss due to change in outside temperature conditions. This combination will maintain a correct inside temperature under normal conditions without the necessity However, outside conditions such as winds and sunlight will not have the same effect on all parts of the building, and the wall thermostat F can only be positioned so as to reflect the effect of these outside conditions on one wall of the building. Also the opening of doors or windows will cause a temporary increase in the heat losses. It is for this reason that the inside thermostat E is used or preferably a plurality of these inside thermostats located at different points in the building so as to respond to the average of inside temperature changes. The control resistance of inside thermostat E is arranged in series with the control resistance of the heat-balancer so as to modify the control eifected by the heat-balancer only when the inside temperature varies materially from the desired inside temperature. Now, a substantial temporary drop in inside temperature at the location of the inside thermostat will so vary the resistance of this thermostat as to call fora fully opened valve or a maximum steam flow provided this thermostat were in complete control of the valve. However, the radiators are still hot and the control valve has been throttled .down by the heat-balancer thermostat so as to restrict the maximum steam flow to an amount just sufficient to offset normal heat losses.

The

resistance of the room temperature thermostat being in series with the resistance of the heatbalancer,- the inside thermostat cannot cause the valve to be opened materially beyond the maximum established by the heat-balancer. There will be a slight increased flow of steam to compensate for the added heat losses, but the temperature at the radiators will not be greatly increased and overshooting will be avoided. On the other hand, if the inside temperature influencing thermostat E temporarily rises too high, this thermostat is ineffective to completely close the valve but can only modify the valve setting to slightly decrease the rate of steam flow. Under normal conditions, that is if the heat losses are substantially equal from all parts of the building and no windows are opened, the inside thermostat E will remain substantially centered and will have little or no controlling effect. The primary control of the supply valve is effected through the heat-balancer so as to maintain a desired temperature in the radiators. This radiator temperature is adjusted by a wall thermostat F in accordance with general outside temperaturechanges which vary the normal heat losses. Finally, the-inside thermostat E acts to compensate for unusual heat losses due to Winds or sunlight that do not directly affect the thermostat F, and also to temporary heat losses resulting, for example, from open windows.

It will be notedthat the main control valve is not intermittently turned on or off but is adjusted for a continuous restricted flow of steam just suflicient to maintain a desired radiator temperature which should, under normal conditions, offset the heat losses. When the system-is first started into operation the steam flow will be restricted as soon as the radiator temperature has reached the value for which heat-balancer thermostat C is set even though the desired inside temperature has not yet been established and the inside thermostat is still calling for heat. This continuous normal steam flow is slightly increasedor decreased by the thermostat F acting to adjust the action of the radiator thermostat C on its control resistance R6. The resistance of the room thermostat is placed in series with this main control resistance Re so as to modify its control of the valve. Under no condi tions (after the system has once adjusted itself for normal operation) can the inside thermostat E cause the control valve to be completely opened eventhough the inside temperature suddenly falls so low that the maximum opening of the valve is called for by this inside thermostat. As a result there is a steady and continuous flow of steam to the radiators just sufficient to replace normal heat losses. The inside thermostats can effect a small variation in this rate of steam flow to ofiset abnormal conditions but no wide overshooting or under-shooting is possible.

Fig. 9 illustrates one example of how this invention could be applied to a processing apparatus instead of to a house heating system. The material to be processed is charged into the evaporator 243. Heat is applied by means of the coil 244 and the vacuum is produced by the action of a condenser or vacuum pump exerted through the vapor discharge pipe 245. As vaporization proceeds the vapors are condensed so that the vapor pressure of the material being evaporated is not permitted to rise above a predetermined point. It is desirable that the material .in the evaporator be kept at a substantially fixed temperature.

At 246 is indicated the instrument panel which contains the pressure gauges and thermometers. At 241 is indicated an observation window, and 248 is the observation platform.

Steam or other heating medium is supplied through pipe 249, the flow of steam to the coil 2&4 being regulated by the valve 250 as in the heating systems described hereinabove. At 25| is a float or thermostatic trap to permit the withdrawal of condensate and non-condensable gases while retaining steam in coils 244 and pipe 252. The thermostat Cis positioned in pipe 252 so as to respond to changes in the temperature of the heating medium within the coil 244, and is connected as before with the heat balancer assembly 28. A thermostat K is positioned in the liquid being processed and is connected through wires 253 with the relay panel M. The heat balancer i3 is connected with this panel through wires 254 and the proportioning motor assembly A is connected with the panel through wires 255. The accessible panel N supports the manually operable resistances by means of which the temperature to be maintained in coil 244 is predetermined.

In an apparatus of this type the temperature of the heating coil 244 should not be permitted to rise too high since this may cause the material being processed to adhere to the coil and reduce the capacity of the unit. Also too high a temperature may affect the flavor, color or odor of the material being treated. The thermostat K acts jointly with the heat balancer to control the operation of valve 250. The temperature to be maintained in the heating coil is set from the control panel N. The thermostat K which registers the actual temperature of the material being treated may be connected up so as to modify the setting of valve 250, through the heat balancer B, as was described in connection with either of the thermostats E or'F hereinabove.

It should be noted that this invention, in any of the forms hereinabove disclosed, can. easily be modified to maintain predetermined pressures instead of temperatures. In fact, in a heating system of-the type disclosed in Fig. 1, the pressure of the steam in the radiators is predetermined as well as the temperature thereof. It will be noted that the thermostat C controls the heat balancer through pressure changes, and in lieu of a thermostat the'pipe l6 could be connected directly with a space in which the pressure is to be maintained at a predetermined point. In any event, whether a predetermined temperature, pressure or vacuum is to. be maintained in a given space, this temperature, pressure or vacuum can be changed and controlled from a remote location by means 01' the improved apparatus herein disclosed.

We claim:

1. In a heat balancer, a pressure chamber having one movable wall, a bulb positioned in a heat exchanger, a. quantity of temperature responsive fluid in the bulb so as to. expand or contract in response to temperature changes in the heating medium within the heat-exchanger, 9. tube connecting the bulb and pressure chamber, a movable element, means actuated by the movable wall of the pressure chamber and bearing on one side of the element, a balancing spring acting on the element'in opposition to the fluid pressure, means for controlling the flow of heating medium to the heat exchanger, means actuated by movements of the element for regulating the flow controlling means, and means for adjusting'tli'e pressure of the balancing spring from a location remote from the heat balancer.

2. In a heat balancer, a pressure chamber having one movable wall, a bulb positioned in a heat exchanger, a quantity of temperature responsive fluid in the bulb so as to expand or contract in response to temperature changes in the heating medium within the heat exchanger, a tubeconnecting the bulb and pressure chamber, a movable element, means actuated by the movable wall of the pressure chamber and bearing on one side of the element, a balancing spring acting on the element in opposition to the fluid pressure, means for controlling the flow of heating medium to the heat exchanger, means actuated by movements of the element for regulating the flow controlling means, and automatic means for adjusting the pressure of the balancing spring in response to temperature changes at a location remote from the heat balancer. T

3. In a heat balancer, a pressure chamber'having one movable wall, a bulb positioned in a heat exchanger, a quantity of temperature responsive fluid in the bulb so as to expand or contract in response to temperature changes in the heating medium within the heat exchanger, a tube connecting the bulb and pressure chamber, a movable element, means actuated by the movable wall of the pressure chamber and bearing on one side of the element, a balancing spring acting on the element in opposition to the fluid pressure, means for controlling the flow of heating medium to the heat exchanger, means actuated by movements of the element for regulating the flow controlling means, means for adjusting the pressure of the balancing spring from a location remote from the heat balancer comprising a spring-compressor including a rotary cam, a reversible electric motor for rotating the cam, and electrically actuated means controllable from a remote location for determining the direction and amplitude of movement of the motor.

4. In a heat balancer, a pressure chamber having one movable wall, a bulb positioned in a heat exchanger, a quantity of temperature responsive fluid in the bulb so as to expand or contract in response to temperature changes in the heating medium .within the heat exchanger, a tube connecting the bulb and pressure chamber, a movable element, means actuated by the movable wall of the pressure chamber and bearing on one side of the element, a balancing spring acting on the element in opposition to the fluid pressure, means for controlling the flow of heating medium to the heat-exchanger, means actuated by movements of the element for regulating the flow controlling means, means for adjusting the pressure of the balancing spring from a location remote from the heat balancer comprising a springcompressor including a rotary cam, a reversible electric motor for rotating the cam, and electrically actuated means controllable from a remote location for determining the direction and amplitude of movement of the motor automatically in response to temperature changes at some predetermined location. a

5. In a heat balancer, a pressure chamber having one movable wall, a bulb positioned in a heat exchanger, a quantity of temperature responsive fluid in the bulb so as to expand or contract in response to temperature changes in the heating medium within the heat exchanger, a tube connecting the bulb and pressure chamber, a movsure of the balancing spring from a location remote from, the heat balancer comprising a spring-compressor including a rotary cam, a reversible electric motor for rotating the cam, and electrically actuated means controllable from a remote location for determining the direction and amplitude of movement of the motor comprising a variable resistance at the remote location and a balancing resistance automatically adjusted by the movement of the motor.

6. In a heat balancer, a pressure chamber having one movable wall, a bulb positioned in a heat exchanger, a quantity of temperature responsive fluid in the bulb so as to expand or contract in response to temperature changes in the heating medium within the heat exchanger, a tube connecting the bulb and pressure chamber, a movable element, means actuated by the movable wall of the pressure chamber and bearing on one side of the element, a balancing spring acting on the element in opposition to the fluid pressure, means for controlling the flow of heating medium to the heat exchanger, means actuated by movements of the element for regulating the flow controlling means, means for adjusting the pressure of the balancing spring from a location remote from the heat balancer comprising a spring-compressor including a rotary cam, a reversible electric motor for rotating the cam, electrically actuated means controllable from a remote location for determining the direction and amplitude of movement of the motor comprising a variable resistance at the remote location, thermostatic means for adjusting this resistance, and a balancing resistance automatically adjusted by the movement of the motor.

'7. In a heat balancer, a pressure chamber having one movable wall, a bulb positioned in a heat exchanger, a quantity of temperature responsive fluid in the bulb so as to expand or contract in response to temperature changes in the heating from the heat balancer comprising a spring-compressor including a rotary cam, a reversible electric motorfor rotating the cam, electrically actuated means controllable from a remote location for determining the direction and amplitude of movement of the motor, and an indicator actuated from the motor for indicating the setting of the heat balancer.

8. In a heat-balancer, a pressure chamber having one movable wall, thermostatic means responsive to temperature changes in a heat-exchanger for varying the pressure in the chamber, a movable element, means actuated by the movable wall of the pressure chamber and pressing on one side of the element, a balancing spring acting on the element in opposition to the fluid pressure, an electrically actuated means for controlling the flow or heatlng medtum to the heat exchanger, a variable resistance for controlling the electrically actuated means, means actuated by the element for varying the resistance, and means for adjusting the pressure of the balancing 9. In a heat balancer, a pressure chamber having one movable wall, thermostatic means responsive to temperature changes in a heat-exchanger for varying the pressure in the chamber, a movable element, means actuated by the movable wall of the pressure chamber and pressing on one side of the element, a balancing spring acting on the element, in opposition to the fluid pressure, an electrically actuated means for controllingthe flow of heating medium to the heat exchanger, a variable resistance for controlling the electrically actuated means, means actuated. by the element for varying the resistance, and. means for adjusting the pressure of the balancing spring from a location remote from the heat balancer.

10. In a heat-balancer, a pressure chamber having one movable wall, thermostatic means responsive to temperature changes in a heat-exchanger !or varying the pressure in the chamber, a movable element, means actuated by the movable wall of the pressure chamber and pressing on one side of the element, a balancing spring acting on the element in opposition to the fluid pressure, and electrically actuated means for controlling the flow of heating medium to the heat exchanger,-a variable resistance for controlling the electrically actuated means, means actuated by the element for varying the resistance, and automatic means for adjusting the pressure 01 the balancing spring in response to temperature changes at a location remote from the heat balancer.

11. In a heat-balancer, a pressure chamber having one movable wall, thermostatic means responsive to temperature changes in a heat-exchanger for varying the pressure in the chamber, a movable element, means actuated by the movable wall of the pressure chamber and pressing on one side of the element, a balancing spring acting on the element in opposition to the fluid pressure, means operable from a location remote from the heat balancer for adjusting the pressure of the spring, a valve for controlling the flow of heating medium to the heat exchanger, a reversible motor for opening or closing the valve to any desired extent, and electrically actuated means including a resistance variable by the element for determining the direction and amplitude of movement of the motor.

DAVID N. CROSTHWAIT, JR. ELLIS G. POWELL.