US2013450A - Control for heating systems - Google Patents

Description

Sept.'3, 1935 w. E. STARK 2,013,450

common FOR HEATING sysrms Filed Oct. 13. 1951 s Sheets-Sheet 1 5' H2); v wwwaa Sept. 3, 1935. w. E. STARK CONTROL FOR HEATING SYSTEMS Filed Oct. 13, 1931 3 Sheets-Sheet 2 Sept. 3, 1935. w. E. STARK 2,013,450

CONTROL FOR HEATING SYSTEMS Filed Oct. 13, 1931 s Sheets-Sheet 3 I x O H v Patented Sept. 3, 1935 CONTROL FORQHEATING SYSTEMS Willet E. Stark, East Cleveland, Ohio, assignor, by mesne assignments, to The Bryant Heater collinpany, Cleveland, Ohio, a corporation of Application October 13, 1931, Serial No. 568,583

1 Claim. (01. 2374) V This invention relates to improvements in controls for heating systems, that is to say automatic means for so operating a heating system as to maintain the temperature of the premises constantly at a desired point, or within a short range of variation. The present invention is designed primarily for use in connection with. liquid or gaseous fuel, but by means of changes within the skill of the experienced worker in the art it may be adapted in some: of its aspects, at least, to use with solid fuels as well.

One of the objects of the invention is the provision of an automatic control for warm air heat-' ing systems, wherein not only the heat supplied to the circulating air is regulated in accordance with a demand for heat, but also one wherein the circulation of air may be started and stopped or varied in volume to conform with the requirements.

Another object is the employment in connection with two different heating systems, using a com- Fig. 2 is an elevational view of the same, taken at right angles to' Fig. 1.

Fig. 3 is a wiring diagram, showing electrical circuits which may be employed in connection with the invention.

Fig. 4 is an elevational view, partly in vertical section, and on a larger scale, showing a fuel valve and associated parts which may be employed in connection with the invention.

Fig. 5 is a detail of a valve operator which may be employed in connection with the invention.

Warm air heating systems, without auxiliaries, are sometimes unsatisfactory, particularly where certain portions of the premises are comparatively distant from the furnace. In order to make the warm air system available in such cases for those portions of the premises which are within proper range of such a system, as well as to remove any possibility of the products of combustion getting into the air stream, I devised the combination warm air and direct radiation system disclosed in my copending application Serial No. 542,370, filed June 5, 1931, where a fluid radiator is located in the air conductor for supplying heat to the air stream, and where other radiators are located inthe remote portions of the premises for heating the latter by direct radiation, all of the radiators being served by a single boiler. The present invention has to do with the provision of an automatic control for such a system, although incidentally including features which are applicable to warm air'systems generally.

In the drawing the boiler of the system is indicated at H], and the air heater, comprising part of the conductor for the air stream, is shown at H. A warm air conduit 12 is shown leading a section l3 of the premises to be heated. It IS to be understood that this section l3 may comprise a number of rooms, and that the conduit I2 may have any number of branches required to supply warm air to such rooms. The return or air inlet conduit for the heater is indicated at 14, and is supplied with a damper l5 pivoted at I6 and adapted to be swung by'means of a crank arm I! from the fullyclosed position illustrated in Fig. 2 to a fully open position at right angles thereto, or any intermediate position. Another one or a plurality of rooms,' is arranged to be heated by direct radiation from one or more radiators l9 which are directly connected with the boiler l0 through steam pipes 20, 2| and 22,

the water of condensation from these pipes flowing back to the boiler through pipes 23 and 24. The condensation water from radiators l9 returns to the boiler through pipes 25, 26 and 21.

Where gaseous fuel is employed, it may be fed to the burner (not shown) in the casing of boiler section 18 of the premises, which may consist of I0 through a pipe 28, in which is mounted a valve 29 of known form comprising a pressure operated diaphragm. Preferably this valve 29 is I one of the type which may be opened and closed by variations in pressure exerted upon the diaphragm, so that it may be adapted to be closed when the pressure of steam in the boiler becomes excessive, as well as when thermostatic mechanism calls for an interruption of the heating operation, and so that it may also be opened to various degrees, dependent upon the degree of steam pressure in the boiler.

Although valves of this general character are well known in the art, and one of the particular design herein disclosed is illustrated in my copending application Serial No. 396,279, filed September 30, 1929, that shown herein will now be briefly described.

The valve housing comprises upper and lower parts 38 and 3 I, separated by a flexible diaphragm 32, to which is centrally attached a disc valve 34 which is adapted to engage a circular valve seat 35. A rod 33 vertically movable in a guide bracket 36 is adapted to bear upon the upper side of diaphragm 32, and carries on its upper end a second diaphragm 31 which is mounted at its periphery in a steam dome or chamber 38. A lever 39, pivoted at 48 in the bracket 36, extends through a slot in the rod 33, and at its free end engages by means of an adjustable fitting a coil spring 4|, the opposite end of which may be suitably connected with the upper part 38 of the valve housing. Spring 4|, working through lever 39. may be adjusted to balance the normal steam pressure exerted upon the upper side of diaphragm 31, so that steam pressure will completely close the valve only when the pressure is excessive. The chamber above diaphragm 31 is connected with the steam chest of the boiler through pipe 42.

Connected with the valve chamber beneath disc 34 there is a gas pipe 41, while another gas pipe 48 is connected with the chamber 49 above the diaphragm 32. When gas is permitted to flow from pipe 28 through pipes 41 and 48 into the chamber 49, pressure builds up in the latter chamber and depresses diaphragm 32 to close the valve. There is also a small relief connection (not shown) adapted to dissipate this pressure and permit the valve to open when the connection between pipes 41 and 48 is interrupted.

The connection between pipes 41 and 48 is made at times by way of a pipe 58 wherein there is a valvecasing 5|, see Fig. 3, in which there is a valve seat for the reception of a mushroom valve 52 on the lower extremity of a rod 53 of insulating material, which carries an armature 54 that is arranged to move up and down within a solenoid 55, having upper and lower coils 56 and 51 respectively. When the upper coil is energized the armature 54 is raised and the valve 52 lifted off its seat,.whereupon gas pressure builds up in chamber 49 and closes valve 219. On the other hand, when coil 51 is energized, annature 54 is drawn downwardly, closing valve 52 and enabling the pressure above diaphragm 32 to bedissipated, whereupon valve 29 opens.

Referring again to Figs. 1 and 2, 58 is a steam pipe leading from the boiler to a radiator 59 mounted in the upper end of the casing of the air heater II. The water condensed in radiator 59 is returned by means of pipes 68 and 6| to the boiler. This radiator is preferably furnished with sheet metal fins so as to provide a large amount of radiating surface and rapid condensation of the steam flowing therethrough whenever there is a current of air thereover. Preferably I provide a forced draft of air through the heater I I by means of a fan or blower 62 mounted upon a shaft 63 which carries a pulley 64' outside of the casing driven by a belt 65 from an electric motor 66.

The crank arm I1 for the damper I5 is connected by means of a link 61 to the outer end of a lever 68 which protrudes from a box 69 containing mechanism for themovement of the lever up and down, and also an electric switch actuated by the lever. 18 is a cable containing electric conductors leading from a thermostat 1| in section I3 of the premises to box 69. From this same box electric cables 12 and 13 lead to solenoid and motor 66 respectively.

In the section I8 of the premises there is a second thermostat 14, from which a cable 15 leads to a switch and motor box 16 arranged to control a valve 9 in the steam pipe 28-. From the box 16 a further cable 11 extends downwardly to solenoid 55.

Referring now to Fig. 3, in which the control mechanism and electric circuits are shown diagrammatically, 18 and 19 are high voltage conductors to which is connected the primary coil 88 of a step-down transformer. To the secondary coil 8| thereof are connected the various pieces of electrical apparatus which effect the automatic control .of the two systems, although,

the motors for driving the blower and operating the valve 9 take high voltage current direct from the line 18,19.

Within the box 69 there is mounted what is known in-the art as a heat motor. As herein shown it comprises two bimetallic strips 82, and

83, which are secured at one end, as indicated at 82 and 83', to a suitable base, the opposite ends of the strips being hook shaped. Surrounding these strips are heating coils 84' and 85, the inner ends of which are electrically connected to the strips, while the remaining parts of the coils are electrically insulated therefrom. A yoke member 86 is mounted upon the hooked ends of the strips 82, 83 and carries a contact 81 which is adapted to engage at times with an adjustable contact 88 supported upon the lower end of a link 89 which is secured at its upper end to an arm 98 that is mounted upon a metal bellows 9| and engages the underside of lever 68, the latter being pivoted to a fixed support at 92. Within the box 69 there is also fixedly mounted a capsule 93 containing-a volatile liquid. A second lever 94 is also pivoted at 95 to a suitable support in the box ,69, and is connected at its outer end by a link 96 with lever 68 so as to move with that lever. The lever 94 serves as a movable support for two mercury tube switches 91 and 98 18 extending from the thermostat H to the box- 69 contains three conductors 18a, 18b and 18c connected as shown. 18c leads to heating coil 84 and 18a leads to heating coil 85. Current to heat both coils flows from the secondary coil 8| of the step-down transformer through a conductor I83 to strip 82, and by way of a connecting conductor I84 to strip 83. Thence it flows through the coils 84 and 85, and back through conductors 18c and 18a to the outer ends of potentiometer coil I8I, flowing inwardly along the coil of the potentiometer to the pointer I82 and down through conductor 18b, returning through conductors I85 and I86 to coil 8|. The position of pointer I82 willdetermine the resistance in the circuits for the two heating coils, and hence will vary the heating effects upon the bimetallic strips 82 and 83, which in turn will cause contact 81 to move either toward the right or the left for each change in temperature of the atmosphere surrounding thermostat 1|. This thermostat having been set for any desired room temperature, any variation therefrom will thus cause contact 81 to take a difierent position to the right or the left of its normal position. Assuming that it moves to the left, and engages contact 08, a circuit will then be set up from coil 8I to conductors I03 and I04, to conductor I0I, yoke 86, contacts 81 and 88 and through a heating coil I08 surrounding capsule 93, and back through a conductor I09 and conductor I06 to coil 8|. The liquid in capsule 8| will thereby be volatilized, and bellows 9| will be expanded, exerting a lifting effort upon lever 68. At the same time the contact 88 is raised. As soon as the circuit through heating coil I08 is broken the pressure within bellows 9| rapidly decreases, tending to lower the lever and the contact 88. The making and breaking of the circuit in this manner recurs rapidly, so that the contact 88 floats just at the point of engagement with contact 81, and hence for any given position of contact 81 there is a definite position of lever 68.

' When the thermostat II is not calling for heat,

the control apparatus will stand as illustrated in Fig. 3 except that pointer I02 will be at one extremity of coil IOI. Under such conditions there will be no current through motor 66, which is connected with line wire I9 by conductor 13a and with mercury tube 91 by a conductor I30 which runs into the higher end of the tube. Another conductor IIO terminates in the tube near the end of conductor 13b.

The mercury tube 98' constitutes a double switch for the control of the two coils of solenoid 55. It has connection at both ends with a conductor III from transformer coil 8I. At the upper end ithas connectionwith a conductor 12c. and at the lower end with a conductor 12b. The latter conductors are in the cable I2, previously mentioned, which also contains a conductor I20. extending from the oppositeside of the transformer coil 8|.

Now, referring to the control for the direct radiation system, the valve 9 in steam pipe 20 comprises a butterfly valve piece II2, to which is attached a crank arm H3. The latter is connected by a link II4 with a crank arm II5 on an electric motor 8, or reduction gearing driven from said motor, the arrangement being such that when the crank arm II5 turns through half a revolution it swings arm II3 through an angle of and when the crank arm II5 turns through the second half of its revolution the crank arm H3 is swung back 90 to its original position. A valve operator of known form which may be employed for this purpose is illustrated in Fig. 5, where the shaft for the butterfly valve is shown at I50. Rigidly secured thereto outside the valve casing is a crank I5I with a ball .end I52. I53 and I54 are elements of a scissors clamp, which elements are urged toward their closed position by a coil spring I55. The clamp elements I53 and I54 embrace the ball end I52 and also embrace a ball end I55 on one arm of a bell crank lever I5I, the other arm of which is the crank arm II3. This lever is loosely mounted upon the shaft I59, as are also the elements I53 'and I54 of the scissors clamp. When the motor IIB turns the crank II5 through an angle of 90 the bell crank H3, I5I turns the scissors clamp through a like angle, and the scissors clamp working through crank arm I 5I turns the valve II 2 until it comes into closed position against a stop I58. The motor crank II5 continues through another 90, pushing against the element I54 of the scissors clamp. The other element I53 of the clamp is kept from turning by its engagement with the ball end I52, the movement of which is stopped with the movement of the valve. The scissors clamp therefore opens against the action of spring I55. Now, when the next operation of motor II5 occurs to cause the movement of crank 5 through another the first 90 of that movement swings the arm I I3 back through an angle of 90, this movement being assisted by the spring I55, which also permits scissors element I54 to swing through the same angle, relieving spring I55 and returning the scissors elements to their closed position. The next 90 of the motor movement then works through the scissors to swing arm I 5I and valve- II2 back to the original position indicated in Fig. 5. The electric circuit H1, H8, for motor H6 includes a choke coil II9 which is adapted normally to prevent the flow of suflicient current to actuate motor I I6. When, however, a circuit is completed through coil I20 wound upon the same core with coil II9, current suflicient to operate the motor will flow through circuit III, H8.

On the same shaft with crank II5 there is a switch arm I2I, the outer end of which is adapted to run upon a ring contact I22 having diametrically arranged arc-shaped protuberances within which are located contacts I23 and I24 which have no electrical connection with the ring. Coil I20 is connected through a conductor I25 with the hub of switch arm I2I, and through a conductor I26 with the ring I22. Contacts I23 and I24 are connected through conductors 15a and 15b with contacts I21 and I28 of thermostat I4. The bimetallic arm of that thermostat is in electrical connection with conductor I26 through a, conductor I29.

The position of the movable arm of thermostat I4 is dependent upon the temperature of that section of the premises heated by direct radiation. Assuming that the parts are in the position illustrated in Fig. 3, and that the temperature has risen to the point for which the thermostat was set, the movable arm of the thermostat will then engage contact I28, and a circuit will be set up from coil I20 through conductors I 26 and I29, thermostat arm I4, contact I28, conductor 15b, contact I24, switch arm I2I and conductor I25 back to coil I20. This flow of current relieves the choking eflect of coil H9, and current then flows through motor II8, turning the crank II5. Switch arm I2I turns at the same time, and moves away from contact I 24.- However it immediately makes contact with ring I22 which shortcircuits thermostat I4 and provides a new path for current through coil I20 by way of conductor I26A. Hence the circuit through the motor is maintained until the arm' I 2| moves off the ring I22 onto contact I23, whereupon the motor stops, having turned valve piece II2 through 90" into the closed position.

Upon the same shaft with crank arm H5 and switch arm I2I there is another switch arm I30, the outer end of which is adapted to make connection with one or the other of two crescent shaped contacts I3I and I32. Whenever the crank II5 moves through 180 the switch arm I30 leaves engagement with one of the contacts I3I or I32. and makes engagement with the other. Conductor Ila leads from contact I3I to binding post I33 of solenoid 55, and conductor He leads from contact I32 to binding post I34 on the solenoid. Conductor I'Ib connects with conductor 12b, previously mentioned. There is a third binding post I35 on the solenoid to which conductor 12a is connected, this conductor extending over to one end of transformer coil 8|.

The upper end of rod 53 in solenoid 55 has a reduced portion which receives the notched ends of two metal bars I36 and I31 that are loosely connected at their outer ends with flexible metal contacts I38 and I39, connected respectively to the binding posts I33 and I34. The binding post I35 is electrically connected with both of coils 56 and 51. Coil 56 is also connected with a contact I40 and coil 51 with a contact I. When the'valve 52 is closed and the bar I36 is in the position shown, coil 56 is in electrical connection with conductor 11a through contact I40, bar I36, contact I38 and binding post I33. When the armature 54 moves upwardly, spreading the bars I36 and I31 in the manner of toggle links, the upper ends of contacts I38 and I39 flex backwardly or outwardly until the bars I36 and I31 are in alignment, and then impart a snap action to the same, forcing them upwardly, whereupon bar I31 engages contact MI and coil 51 is brought into electrical connection with conductors 11c and 120 through contact I4I, bar I31, spring contact I39 and binding post I34.

The parts as illustrated in Fig. 3 are in the positions which would be assumed when the air system section I3 of the premises was heated to the extent called for by thermostat H and when the section I8. of the premises was below the temperature required by thermostat 14. Steam is thenflowing through radiators I9, valve 9 being open, and it is also flowing through radiator 59, but there is little condensation occurring in the latter radiator because the circulation of air thereover is interrupted both by the closed condition of damper I5 and by the inactive condithe resistance through one of the coils 84 and 85 and decreasing it through theother. The contact 81 will then move toward the left and engage contact 86, whereupon heating coil I08 will be energized and the pressure within bellows 9I will be increased, raising the lever 68. As soon as this action becomes sufficient to swing the lever 68 thromgh a predetermined fraction of its total possible movement, say one-sixth, the mercury globules 99 and I will travel to the opposite ends of mercury tubes 91 and 98. When this occurs the circuit through motor 66 by way of conductors 13a, 13b and II 0 will be completed, starting the blower 62. The raising of the lever 68 will at the same time have lifted link 61 and swung crank I1 to open damper I part way. Circulation of air over the radiator 59 and through the section I3 of the premises will then take place. With the damper I5 in an interme-: diate position corresponding to any intermediate position of lever 68, the air handling capacity of blower 62 is reduced, and the condensing capacity of radiator 59 is correspondingly reduced below the generating capacity of boiler I0, causing the steam pressure in the system to rise. Through pipe 42 this steam pressure is communicated to diaphragm 31 and thence to valve piece 34, reducing the flow of gas until the rate of heat generation is just equal to the demand. The rate .ber 49 of valve 29 and close that valve.

At the same time globule I00 will function to connect conductors III and 12c leading to binding post I34 on solenoid 55. This will have no effect however, as the bar I31 is out of engagement with contact I4I. Hence the solenoid 55 is not afiected, which is as it should be because the valve 52 is already in closed position, which corresponds to open position of the fuel valve 29.

Now, assume that after a length of time the temperature in that section of the premises wherein thermostat 14 is situated rises to the predetermined desired point, causing thermostat arm 14 to engage contact I28. A circuit is thereby made through coil I20 as heretofore explained, and the choking effect of coil H9 is relieved, permitting current to flow through motor '6 in amount suflicient to operate the same. As a result the crank arm II5 travels through an arc of 180, valve piece I I2 is shifted to the closed position, and switch arm I2I moves over-onto contact I23, thereby breaking the circuit through coil I20 and stopping the motor I I6. At the same time switch arm I30 is caused to leave crescent shaped contact I 32 and to engage .crescent shaped contact I3I. This is the position of switch arm I30 for lifting valve 52, but it is ineffective because the circult includes the contacts at the right-hand end of mercury tube 98, which are not joined because the globule I00 is at the left end of the tube. The valve 9 being closed however shuts off the flow of steam to radiators I9, whereby all of the steam generated in the boiler is then available for radiator 59.

As the temperature in the premises surrounding thermostat 1I rises toward the desired value, the thermostat pointer I02 gradually moves back to such position that the current through heating coils 84 and 85 changes in a manner such as to return yoke 86 to such position that lever 63 swings downwardly enough to cause globules 99 and I00 to travel again to the right-hand ends of tubes 91 and 98, whereupon the current through motor 66 is interrupted, stopping the blower 62, and conductors III and 1212 are electrically joined. The damper I5 is also moved toward closed position by the lowering of lever 68 and link 61.

Both of the switches 98 and I30, I3I are now in position for opening valve 52 by the energization of coil 56. The circuit may be traced as follows: From coil 8| of the transformer through conductors III, 12b and 11b to switch arm I30, which is then in engagement with contact I 3I from the latter contact through conductor 11a to binding post I33, through spring contact I38, bar I36, contact I40, coil' 56, binding post I35, and conductor 12a back to coil 8I. Valve 52 consequently opens, enabling gas to flow into the cham- The latter valve remainsclosed as long as both thermostats H and 14 remain satisfied.

If thermostat 14 should be the first one to call for heat, engagement would be made between the swinging arm of that thermostat and contact I21, which would complete a circuit through coil I20, the switch arm I2I being in the dotted line position at the time. The valve 9 would then be opened and the switch arm I30 would return to its full line position. Current would. then flow from coil 8I through conductors III, 12b, and 11b through switch arm I30, contact I32, con-'- ductor 11c, binding post [34, spring contact 139, bar 131 (then in its upper position), contact Ml, coil 51, binding post 135 and conductor 12a back to coil 8|.

It will be observed that the circuit through coil 51 includes both of the switches 98 and I 30, 132 in parallel, so that when either one of these switches is closed the coil 51 will be energized to eifect the opening of the fuel valve. The coil 56 however is in a circuit including switches 98 and 130, 131 in series, so that before this coil can be energized to effect the closing of the fuel valve, both of the said switches must be closed. There is, however, control of the heating medium for each system individually by means other than the fuel valve, that is to say, when thermostat 1| is satisfied switch 91 opens the circuit for motor 66 and lever 68 descends to close damper 15; while for the direct radiation system, when the thermostat 14 is satisfied valve 9 closes to shut off the flow of steam to the radiators l9. Hence there is a double control for each system, the fuel valve going to the on position when either one of the individual controls goes to the on position, and the fuel valve going to the off position only after both of the individual controls have gone to the off position. Furthermore the degree of opening of the fuel valve is controlled not only in proportion to the demand for heat in the direct radiation system, but also in proportion to the demand in the indirect system; that is to say, when the flow of air through the air conductor is slowed down on account of approach to the desired temperature level in the air heated part of the premises, then the steam pressure increases because of the lowered rate of condensation of steam in radiator 59. Consequently the gas intake valve is moved toward closed position, balancing the heat output to the demand. In other words, there is a coordination. of air flow and the heat applied thereto which best fits any given condition of variance between desired temperature and actual temperature. The control therefore tends toward constant application of heat and air flow in controlled amounts rather than in intermittent application of either or both.

In the warm air system as herein disclosed there is both a blower and a damper for controlling the flow of air. It will be understood that either of these devices could be employed singly, with more or less satisfactory results, although the use of both, is deemed advisable. It will also be understood that the steam to radiator 59 could be turned on and off by means similar to that employed in connection with valve 9, but this is not considered necessary in view of the fact that the condensation of steam in radiator 59 when the air system is not in operation can be kept down to a low minimum.

In the foregoing description I have necessarily gone somewhat into detail in order to explain fully the particular embodiments of the invention herein illustrated, but I desire it to be understood that such detail disclosures are not to be construed as amounting to limitations, except as they may be included in the appended claim.

Having thus described my invention, I claim:

In apparatus of the class described, two separate heating systems, a common source of heat for said two systems comprising a fluid fuel burner, a fuel conductor leading to said burner, an electrically controlled valve in said fuel conductor, an electric circuit adapted when energized to cause the opening of said valve, said circuit including two .thermostatically controlled switches. in parallel one for each system, whereby the' closing of either of them will energize the circuit, and a second circuit adapted when ener gized tocause the closing of said valve, said second circuit including two thermostatically controlled switches in series, one for each system, whereby the circuit will be energized for closing the valve only when both switches are closed.

WILLET E. STARK.

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