Furnace with Manifold for Controlling Supply of Heated Liquid to Multiple Heating Loops

Abstract

A furnace includes a pump in a circuit through a heat exchanger and a manifold having a plurality of discharge openings in a first area and return openings in a second area connected by a transfer area with each discharge and return feeding a respective heat loop. A bypass in the circuit includes a temperature controlled protection valve connected between the bypass and the manifold. The heated liquid inlet of the manifold is connected to the manifold in the first area with the plurality of discharge openings at a position between the plurality of discharge openings and the plurality of return openings. The manifold is defined by a rectangular chamber divided longitudinally and diagonally by a transverse wall which terminates at one end at a position spaced from an adjacent end of the chamber to define an undivided portion of the chamber at the end which forms the transfer area.

Description

This invention relates to a furnace and particularly to a manifold for the furnace which provides connections for two or more liquid loops or drops each for providing heating through a separate heat exchanger to a separate area to be heated, where the manifold is arranged to control the supply of heated liquid from the furnace to the separate heating loops. There may be only two loops or more loops depending on capacity and requirements.

The arrangement herein provides a simplified form of manifold which can be mounted in the circuit in which the liquid, typically water, is heated in the heat exchanger of the furnace in order to supply the heated water to two or more loops.

The arrangement herein is particularly well suited for outdoor wood furnaces or any exchanger where multiple buildings are heated.

SUMMARY OF THE INVENTION

According to the invention there is provided a furnace for heating a heat transfer liquid comprising:

a furnace heat exchanger having a heated liquid outlet and a cooled liquid return so that cooled liquid returned to the return passes through the furnace heat exchanger to be heated and discharged through the heated liquid outlet;

a heating system in the furnace for applying heat to the furnace heat exchanger to heat the liquid;

a furnace pump for pumping the liquid in a circuit through the furnace heat exchanger;

a manifold connected in the circuit between the liquid outlet and liquid return;

the manifold having a heated liquid inlet for receiving the heated liquid from the heated liquid outlet and a cooled liquid outlet for supplying cooled liquid to the liquid return;

the manifold having a plurality of discharge openings and a plurality of return openings;

the discharge openings being collected in adjacent positions in a first area of the manifold and the return openings being collected in adjacent positions in a second area of the manifold with the first and second areas being connected by a transfer area of the manifold for transfer of liquid therebetween;

each discharge opening being associated with a respective return opening for connection to a respective supply loop including a respective loop pump and a respective output heat exchanger for heating a respective zone with liquid being extracted from the manifold by the loop pump through the respective discharge opening and returned to the respective return opening;

the heated liquid inlet of the manifold being connected to the manifold in the first area with the plurality of discharge openings at a position between the plurality of discharge openings and the plurality of return openings.

In a preferred arrangement there is provided a bypass in the circuit for liquid to bypass the manifold together with a temperature controlled protection valve connected between the bypass and the manifold, the valve being operated to control flow between the manifold and the bypass such that when liquid at the cooled liquid return is below a predetermined temperature the valve operates to halt passage through the manifold and, as a temperature of the liquid increases, the valve is opened to allow passage through the manifold dependent on the increasing temperature. In other words, when the liquid at the cooled liquid return is below the predetermined temperature the valve operates to halt passage from the manifold and, as the temperature of the liquid increases, the valve is opened to allow passage through the manifold back to the furnace dependent on the increasing temperature.

This arrangement therefore tends to reduce the amount of heated liquid available to be transferred to the separate loops. However the loops each include their own separate pump so that the amount of water passing through each loop remains typically at a constant value. The manifold therefore provides a compensation arrangement where some of the water returned by the loop must pass to the discharge opening to that loop since insufficient water is available from the circuit within the furnace.

In addition the arrangement herein can provide the possibility for the total volume of liquid pumped through the loops to be different from the volume passing through the circuit. Typically the volume passing through the loops is less than the available liquid from the circuit. However in some cases the available volume from the circuit may be less than that which is taken by the loops.

Preferably the heated liquid inlet of the manifold is connected to the manifold in the first area separate from the transfer area between the plurality of discharge openings in the first area and the plurality of return openings in the second area. In this way cooled water returning from the loops to the return openings of the manifold access the heated liquid entering the heated liquid inlet to mix with that heated liquid before the mixed liquid reaches the discharge openings. This prevents a mode of operation in which one of the discharge openings to one of the loops receives more heat than the other or others of the discharge openings. In this way the heat available in the heated liquid is balanced between each of the loops.

Preferably the cooled liquid outlet is connected to the transfer area.

As stated above in many cases the sum of volumes pumped by the loop pumps is different from a volume pumped by the furnace pump.

The arrangement is particularly effective where a sum of volumes pumped by the loop pumps is greater than a volume pumped by the furnace pump and allowed to pass through the manifold by the protection valve.

Preferably the protection valve is connected between cooled liquid outlet of the manifold and the bypass and the protection valve controls discharge of liquid from the cooled liquid outlet of the manifold. In this arrangement preferably the protection valve is connected to the manifold at the transfer area.

In a particularly effective arrangement the manifold comprises a chamber divided longitudinally by a transverse wall into the first area on a first side of the wall and the second area on a second side of the wall and wherein the transverse wall terminates at one end at a position spaced from an adjacent end of the chamber to define an undivided portion of the chamber at said end which forms the transfer area.

In this arrangement the heated liquid inlet of the manifold is preferably arranged on one side the transverse wall in the first area.

While other shapes can be used, preferably the chamber is rectangular in cross-section to define four walls at right angles with the discharge openings in a first wall and the return openings in a second wall.

Where the chamber is rectangular, preferably the discharge openings are located in a first wall and the return openings in a second wall at right angles to the first wall with the transverse wall arranged diagonally to the first and second walls. In this arrangement preferably the heated liquid inlet is located in a third wall and the cooled liquid outlet is in a fourth wall.

Preferably there is a transfer channel for the heated liquid along the third wall for carrying the heated liquid to the inlet therein.

According to a second aspect of the invention there is provided a furnace for heating a heat transfer liquid comprising:

a furnace heat exchanger having a heated liquid outlet and a cooled liquid return so that cooled liquid returned to the return passes through the furnace heat exchanger to be heated and discharged through the heated liquid outlet;

a heating system in the furnace for applying heat to the furnace heat exchanger to heat the liquid;

a furnace pump for pumping the liquid in a circuit through the furnace heat exchanger;

a manifold connected in the circuit between the liquid outlet and liquid return;

the manifold having a heated liquid inlet for receiving the heated liquid from the heated liquid outlet and a cooled liquid outlet for supplying cooled liquid to the liquid return;

the manifold having a plurality of discharge openings and a plurality of return openings;

the discharge openings being collected in adjacent positions in a first area of the manifold and the return openings being collected in adjacent positions in a second area of the manifold with the first and second areas being connected by a transfer area of the manifold for transfer of liquid therebetween;

each discharge opening being associated with a respective return opening for connection to a respective supply loop including a respective loop pump and a respective output heat exchanger for heating a respective zone with liquid being extracted from the manifold by the loop pump through the respective discharge opening and returned to the respective return opening;

wherein the manifold comprises a chamber divided longitudinally by a transverse wall into the first area on a first side of the wall and the second area on a second side of the wall and wherein the transverse wall terminates at one end at a position spaced from an adjacent end of the chamber to define an undivided portion of the chamber at said end which forms the transfer area.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:

FIG. 1 is an isometric view of a manifold of a furnace according to the present invention wherein the heating system which applies heat to liquid in a circuit is shown only schematically.

FIG. 2 is an isometric view from the opposite side relative to FIG. 1 showing the furnace of FIG. 1 and including two heat transfer loops connected to the manifold which are again shown only schematically.

FIG. 3 is an end elevational view of the manifold of FIG. 1.

FIG. 4 is a cross-sectional view along the lines 4-4 of FIG. 3.

FIG. 5 is a cross-sectional view along the lines 5-5 of FIG. 3.

FIG. 6 is a front elevational view of the manifold of FIG. 1.

FIG. 7 is a cross-sectional view along the lines 7-7 of FIG. 6.

FIG. 8 is a cross-sectional view along the lines 8-8 of FIG. 6.

In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION

In FIGS. 1 and 2 is shown a furnace 10 arranged for heating a heat transfer liquid filter communicates the liquid to different locations for heating zones to be heated by the furnace. The furnace comprises a manifold 11 which is connected to a furnace heat exchanger 12 within a chamber 13 where the heat exchanger 12 receives heat from a heat source schematically indicated at 14 so as to apply heat to the transfer liquid within the heat exchanger 12. The furnace heat exchanger has an outlet 15 and a cooled liquid return 16 so that the cooled liquid passes through the furnace heat exchanger 12 to be heated and discharged through the outlet 15. A furnace pump 17 attached to the manifold 11 has an inlet 18 for receiving the heated liquid and transferring the liquid through the pump after a rate determined by the pump into the manifold 11. The manifold 11 further includes a return pipe 19 which carries cooled liquid and returns it through a shutoff valve 20 a coupling 21 which feeds the cooled liquid back to the inlet 16.

This arrangement thus provides a circuit around which the liquid is pumped so as to pass through the heat exchanger 12 and to transfer heat from the source 14 into the liquid within the manifold 11.

The liquid is typically water often supplemented by anti-freezing agents and other materials known to persons skilled in the art. However liquids can be used which transfer heat from the source 14 to the areas to be heated.

The manifold 11 includes two discharge openings 22 and 23 from which the heated liquid within the manifold can be extracted and transferred through heating loops to two heat exchanges 24 and 25. Thus the heat exchanges are located on a respectable loop 26, 27 each of which includes a respective pump 28, 29 for transferring the liquid around the loop from the discharge opening 22, 23 back to a return opening 30A, 30B at the manifold 11. The rate of flow of the liquid around the loops is determined by the pumps 28 and 29.

The manifold further includes a bypass duct 31 connected on a downstream side 32 of the pump. At the inlet 18 to the pump is provided a shutoff valve 33 which controls the entry of the heated water into the inlet of the pump. The bypass duct 31 is connected to a boiler protection valve 34. Valves of this type are well known to persons skilled in the art and include a temperature controlled valve element 35 which allows water to pass from the bypass 31 to the return duct 19. This flow is closed off as the temperature at the valve 34 increases and instead liquid is drawn from an outlet 36 of the manifold 11. In this way on startup of the furnace while the liquid is not yet heated to the required temperature, all of the flow bypasses the manifold 11 through the bypass duct 31 allowing the temperature of the heat transfer liquid to be rapidly increased by circulation through the heat exchanger 12. Only when the temperature in the transfer liquid increases does the valve 34 open to gradually close off flow through the bypass duct 31 while gradually increasing the flow from the outlet duct 36 of the manifold 11. When operating at full temperature, the bypass duct 31 is fully closed by the valve 34 and all flow passes through the manifold 11.

This boiler protection valve 34 thus protects the boiler by avoiding continual low temperatures within the heat exchanger 12 which could damage the heating system. However the boiler protection valve 34 is the only such valve within the systems of the loops 26 and 27 contained no similar boiler protection valve as this is not required as explained hereinafter.

The manifold 11 comprises a chamber 37 which is formed as a square or rectangular duct closed at both ends are 38 and 39. The duct is divided into two separate areas by a transverse wall 40 so as to form a second area of 41 above the wall 40 and the first area 42 below the wall 40. As best shown in FIG. 7 and eight, the wall 40 is a diagonal wall extending from an apex between walls 43 and 44 of the chamber diagonally to an apex between walls 45 and 46 of the chamber. Thus each of the areas 41 and 42 is generally triangular in cross-section and extends partly along the chamber from the end of 38 to a position spaced from the end of 39.

The end of the dividing wall 40 is shown best in FIG. 4 where to be noted that the end 47 is located in a position spaced from the end 39 of the chamber so as to form a transfer area 48 in the chamber 37 which is defined by the full extent of the chamber 37.

In this way the manifold is divided into the second area 41 defined by the front wall 43, the top wall 45 and the dividing wall 40. The manifold also is divided into the first area 42 defined by the bottom wall 44, the rear wall 46 and the dividing wall 40.

As best shown in FIG. 7, the outlet ducts 22 and 23 are connected to the bottom wall 44 buddies into the first area 42. Also the return openings 30A and 30B are connected into the front wall 43 of the manifold that is into the second area 41 above the dividing wall 40.

The manifold 11 is thus divided by the diagonal dividing wall 40 into the first area 42 at which the discharge openings are connected, the second area 41 into which the return openings are connected and the transfer area 48 at the position in the chamber 37 beyond the end 47 of the wall 40. The discharge openings 22 and 23 are located at spaced positions along the first area spaced from the end 47 of the wall and thus spaced from the transfer area. In the embodiment shown there are two such discharge openings corresponding to two transfer loops for heating two zones. However it will be appreciated that more than two discharge openings can be provided in this first area at spaced positions along the area. Symmetrically the return openings 30A and 30B are connected at the front wall 43 again at spaced positions along the length of the second area spaced from the transfer area defined by the end 47 of the transverse wall. Again that there can be more than two such return openings to correspond to the number of discharge openings. The discharge and return openings are longitudinally offset along the manifold, that is the discharge and return openings are staggered each from the next, to provide space for suitable couplings of an arrangement well known to a person skilled in the art.

As best shown in FIG. 4, the heated water from the pump 17 passes into the outlet 32 which communicates the heated liquid either to the bypass duct 31 or to a transfer duct 50 which communicates the heated water to the manifold 11. The transfer duct connects to a communication duct 51 which carries the heated water along the rear of the manifold chamber 37 to communicate the heated water into the first area 42 at the rear wall 46 where an opening 53 is provided. Thus the opening 53 for the heated water into the manifold is located in the rear wall 46 communicating with the first area 42 at a position spaced longitudinally of the outlet openings 22 and 23 in a direction toward the end 47 of the dividing wall 40. Thus the inlet opening 53 is located within the first area 42 at a position spaced from the transfer area 48.

The cooled liquid entering the return duct 19 through the valve 34 passes along an inlet coupling 54 of the valve 34 from the top wall 45 of the chamber 37 out of position within the transfer area 48. The inlet coupling 54 includes a collar 55 surrounding a discharge opening 56 in the top wall 45 so the collar projects downwardly into the manifold undefined and open mouth 57 of the collar at a position adjacent the transverse wall 40. However it will be appreciated that in other arrangements the collar may not protrude downwardly as described hereinbefore.

In the event that the total volume of liquid drawn from the manifold by the two or more loops is different from the amount of liquid entering and leaving the manifold in the heating circuit, this difference is accommodated by movement of liquid in the manifold between the areas 41 and 42 and through the transfer area 48.

In a situation where the sum of the volumes pumped by the loop pumps 28 and 29 is greater than the volume of liquid entering the manifold from the inlet 53, this difference is taken up by liquid being pulled into the first area 42 from the second area 41 through the transfer area 48. This liquid is drawn from the return openings 30A and 30B so this extra liquid passes along the second area 41 to the transfer area and then enters the first area 42 to be pulled out of the discharge openings 22 and 23 by the pumps 28 and 29.

As best shown in FIG. 4, the position of the inlet 53 is such that the cooled water turning from the second area 41 around the end 47 of the dividing wall 40 passes the inlet 53 before it reaches the discharge openings 23 and 22. In this way the cooled water which enters the area 42 from the return openings is mixed with the heated water from the inlet 53 before it reaches the discharge openings at 23 and 22. On reaching the first discharge opening 23 just beyond the inlet 53, the liquid is mixed to a constant temperature so that the liquid discharging through the opening 23 is at the same temperature as the liquid discharging through the opening 22.

In this way the manifold balances the liquid flow between the two or more loops while ensuring that neither of the loops is starved of heat. This occurs whether the initial installation is arranged so that the total volume of the loops is greater than the total volume of the heating circuit or whether the volume of the heating circuit is temporarily reduced by the operation of the boiler protection valve 34.

The arrangement described herein and therefore provides a simple manifold arrangement which effectively balances and controls the liquid movement while providing a simple construction which can be readily manufactured.

The arrangement can be readily and simply installed as the individual loops are of a simple construction without any necessity for control valves.

The arrangement provides for a temperature difference between the supply and return of up to 50° on the primary distribution loops to deliver heat load at a much lower rate. The arrangement can ensure adequate flow and water temperature into the heat exchanger. The arrangement can eliminate the need to make manifold using plumbing fittings when setting up the multiple distribution loops for different buildings all zones. In one embodiment the construction provides two supply ports and two return ports. However three or more ports cannot be used. The arrangement herein can enable the use of 1 inch underground pipe for much longer primary distribution lines and still deliver the required heat load. The arrangement herein can allow much smaller more economical pumps to be used on the distribution loops. The simple construction can enable a significant reduction in the plumbing time and therefore the cost of installation. These simple construction of the manifold may enable the installation without professional assistance again reducing the cost.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

Claims

1. A furnace for heating a heat transfer liquid comprising:

a furnace heat exchanger having a heated liquid outlet and a cooled liquid return so that cooled liquid returned to the return passes through the furnace heat exchanger to be heated and discharged through the heated liquid outlet;

a heating system in the furnace for applying heat to the furnace heat exchanger to heat the liquid;

a furnace pump for pumping the liquid in a circuit through the furnace heat exchanger;

a manifold connected in the circuit between the liquid outlet and liquid return;

the manifold having a heated liquid inlet for receiving the heated liquid from the heated liquid outlet and a cooled liquid outlet for supplying cooled liquid to the liquid return;

the manifold having a plurality of discharge openings and a plurality of return openings;

the discharge openings being collected in adjacent positions in a first area of the manifold and the return openings being collected in adjacent positions in a second area of the manifold with the first and second areas being connected by a transfer area of the manifold for transfer of liquid therebetween;

each discharge opening being associated with a respective return opening for connection to a respective supply loop including a respective loop pump and a respective output heat exchanger for heating a respective zone with liquid being extracted from the manifold by the loop pump through the respective discharge opening and returned to the respective return opening;

the heated liquid inlet of the manifold being connected to the manifold in the first area with the plurality of discharge openings at a position between the plurality of discharge openings and the plurality of return openings.

2. The furnace according to claim 1 wherein there is provided a bypass in the circuit for liquid to bypass the manifold and a temperature controlled protection valve connected between the bypass and the manifold, the valve being operated to control flow between the manifold and the bypass such that when liquid at the cooled liquid return is below a predetermined temperature the valve operates to halt passage through the manifold and, as a temperature of the liquid increases, the valve is opened to allow passage through the manifold dependent on the increasing temperature.

3. The furnace according to claim 1 wherein there is provided no temperature controlled protection valve in the loops.

4. The furnace according to claim 1 wherein the heated liquid inlet of the manifold is connected to the manifold in the first area separate from the transfer area between the plurality of discharge openings in the first area and the plurality of return openings in the second area.

5. The furnace according to claim 1 wherein cooled liquid outlet is connected to the transfer area.

6. The furnace according to claim 1 wherein a sum of volumes pumped by the loop pumps is different from a volume pumped by the furnace pump.

7. The furnace according to claim 1 wherein a sum of volumes pumped by the loop pumps is greater than a volume pumped by the furnace pump and allowed to pass through the manifold by the protection valve.

8. The furnace according to claim 1 wherein the protection valve is connected between cooled liquid outlet of the manifold and the bypass.

9. The furnace according to claim 1 wherein the protection valve controls discharge of liquid from the cooled liquid outlet of the manifold.

10. The furnace according to claim 1 wherein the protection valve is connected to the manifold at the transfer area.

11. The furnace according to claim 1 wherein the manifold comprises a chamber divided longitudinally by a transverse wall into the first area on a first side of the wall and the second area on a second side of the wall and wherein the transverse wall terminates at one end at a position spaced from an adjacent end of the chamber to define an undivided portion of the chamber at said end which forms the transfer area.

12. The furnace according to claim 11 wherein the heated liquid inlet of the manifold is arranged on one side the transverse wall in the first area.

13. The furnace according to claim 9 wherein the chamber is rectangular in cross-section to define four walls at right angles with the discharge openings in a first wall and the return openings in a second wall.

14. The furnace according to claim 11 wherein the chamber is rectangular in cross-section to define four walls at right angles with the discharge openings in a first wall and the return openings in a second wall at right angles to the first wall with the transverse wall arranged diagonally to the first and second walls.

15. The furnace according to claim 14 wherein the heated liquid inlet is located in a third wall.

16. The furnace according to claim 15 wherein there is a transfer channel for the heated liquid along the third wall for carrying the heated liquid to the inlet therein.

17. The furnace according to claim 15 wherein the cooled liquid outlet is in a fourth wall.

18. A furnace for heating a heat transfer liquid comprising:

a furnace heat exchanger having a heated liquid outlet and a cooled liquid return so that cooled liquid returned to the return passes through the furnace heat exchanger to be heated and discharged through the heated liquid outlet;

a heating system in the furnace for applying heat to the furnace heat exchanger to heat the liquid;

a furnace pump for pumping the liquid in a circuit through the furnace heat exchanger;

a manifold connected in the circuit between the liquid outlet and liquid return;

the manifold having a heated liquid inlet for receiving the heated liquid from the heated liquid outlet and a cooled liquid outlet for supplying cooled liquid to the liquid return;

the manifold having a plurality of discharge openings and a plurality of return openings;

the discharge openings being collected in adjacent positions in a first area of the manifold and the return openings being collected in adjacent positions in a second area of the manifold with the first and second areas being connected by a transfer area of the manifold for transfer of liquid therebetween;

each discharge opening being associated with a respective return opening for connection to a respective supply loop including a respective loop pump and a respective output heat exchanger for heating a respective zone with liquid being extracted from the manifold by the loop pump through the respective discharge opening and returned to the respective return opening;

wherein the manifold comprises a chamber divided longitudinally by a transverse wall into the first area on a first side of the wall and the second area on a second side of the wall and wherein the transverse wall terminates at one end at a position spaced from an adjacent end of the chamber to define an undivided portion of the chamber at said end which forms the transfer area.

19. The furnace according to claim 18 wherein the heated liquid inlet of the manifold is arranged on one side the transverse wall in the first area.

20. The furnace according to claim 18 wherein the chamber is rectangular in cross-section to define four walls at right angles with the discharge openings in a first wall and the return openings in a second wall at right angles to the first wall with the transverse wall arranged diagonally to the first and second walls.