US3258203A

US3258203A - Hot-water heating system

Info

Publication number: US3258203A
Application number: US386625A
Authority: US
Inventors: Kurz Adolf; Heinz Van Lier
Original assignee: Junkers and Co GmbH
Current assignee: Junkers and Co GmbH
Priority date: 1963-08-01
Filing date: 1964-07-31
Publication date: 1966-06-28
Anticipated expiration: 1983-06-28
Also published as: CH425139A; GB1080553A; BE651305A; NL6408794A

Description

June 28, 1966 A. KURZ ETAL HOT-WATER HEATING SYSTEM 4 Sheets-Sheet l Filed Ju'ly 31. 1964 P pwz www www Z l Wad f. mkv

June 28, 1966 A. KURZ ETAL 3,258,203

HOT-WATER HEATING SYSTEM Filed July 51, 1964 4 Sheets-Sheet 2 June 28, 1966 A. KURZ ETAL 3,258,203

HOT-WATER HEATING SYSTEM Filed July 51, 1964 4 Sheets-Sheet 5 June 28, 1966 A. KURZ ETAL HOT-WATER HEATING SYSTEM Filed July s1. 1964 FVG. 6

4 Sheets-Sheet 4.

United States Patent O 3,258,203 HOT-WATER HEATING SYSTEM Adolf Kurz and Heinz van Lier, Wernau, Germany, assignors to `lunkers & Co. G.m.b.H., Wernau, Germany Filed July 31, 1964, Ser. N0. 386,625 Claims priority, application Germany, Aug. 1, 1963, J 24,173 17 Claims. (Cl. 237-8) rIhe present invention relates to lcentral heating systems in gener-al, and more particularly to an improved hotwater heating system. Still more particularly, the invention relates to improvements in hot-water heating systems which operate on the principle of forced circulation created by a motor-driven circulating pump controlled by outside thermostats or room fthermostats.

In many presently known hot-water heating systems wherein the source of hea-t comprises a gasJheated heat exchanger, the heat exchanger normally comprises one or more packages of laminations or fins which surround a length of the water containing coil and are heated by flames or gaseous products of combusti-on produced by a gas burner. A serious drawback of such hot-Water heating systems is that the spaces between the ns of the heat exchanger :become clogged after short periods of use to thereby reduce the efficiency of the heat exchanger. The reason for clogging of the heat exchanger is that such hot-water heating systems normally comprise a motordriven circulating pump ywhich operates intermittently in response to impulses received from a room thermostat or from another starting device to cause circulation of water through the coil. When the pump is started, it begins to circulate a stream of cold water, or comparatively cold water, which ows through the heat exchanger. Since the rate at which the water is circulated in response to operation of the pump is determined in advance, the quantity of water flowing through the heat exchanger is constant and the latter transmits to such water `a certain quantity of heat energy. Consequently, the heating effect is low when the circulating pump is started, which means that the exposed surfaces of the fins are coated with a layer of condensate which is drawn from the surrounding -air and promotes the clogging of spaces between the adjoining fins.

In order to reduce such deposition of condensate, it was already proposed to return a certain quantity of freshly heated water into a portion of the coil immediately upstream of the heat exchanger so that hot water blends with colder water and the heat exchanger receives a preheated mixture rather than a stream of cold or comparatively cold liquid. Such blending -is continued until the water temperature in the entire coil rises to a predetermined value at which no further precipitation of condensate takes place or at which the deposition of condensate is negligible. Of course, the apparatus for effecting such mixing of hot and cold water contributes greatly to the bulk, initial cost and maintenance cost of the hotwater heating system. In addition, such blending `apparatus normally comprises complicated control devices which are prone to malfunction and must lbe serviced by highly skilled persons.

Therefore, it was already proposed to replace such blending apparatus by the provision of a main heater Iand an auxiliary heater which latter is used -to prevent the water temperature from descending below a predetermined value, i.e., the -auxiliary heater insures that the water temperature remains ybetween a predetermined minimum value land a predetermined maximum value. Of course, this means that -the hot-water heating system must comprise two heaters, two burners and a correspondingly Patented June 28, 1966 ICB kincreased number of valves, piping, control elements and other accessories which Vadd to the bulk, cost and complicatedness of the assembly.

Accordingly, it is an important object of the present invention to provide a very simple, reliable and compact -hot-water heating system which avoids the drawbacks of conventional heating systems and wherein the deposition of condensate on the fins of the heat exchanger is eliminated in a novel way.

Another object of the invention is to provide a hotwater heating system whose operation is automatic and wherein a small number of comparatively simple auxiliaries suliices to prevent clogging of spaces between the fins of the heat exchanger.

A further object of the invention is to provide `a hotwater heating system wherein the heating of the heat exchanger produces little noise and wherein the admission of -fuel to the burner or burners may take place in a fully automatic way and at low water pressure.

With the above objects in view, one feature of ou present invention resides in the provision of a hot-water heating system which comprises a coil defining an endless path for a supply of water, a pump which circulates water in :the coil, a =burner for heating the water which circulates in the coil, a normally closed regulating valve provided in a con-duit which supplies gas or yanother fuel to the burner, means for producing a pressure dilferential in two spaced portions of the coil when the pump operates to circulate the water, a safety device comprising a pair of water-iilled chambers each communicating with one of the two spaced portions of the coil so that the water pressure in one of the chambers exceeds the Water pressure in the other chamber, actuating means operatively connected with the regulating valve to initiate :the admission of fuel to the burner in response to a predetermined pressure differential in the chambers, and a throttling device comprising a thermostat valve which is mounted in the coil upstream of the point where the other chamber communi-V cates with the coil. This thermostat valve serves to throttle the flow of water at least at such times when the waiter temperature in the coil is below a predetermined va ue.

The burner heats the tins of a heat exchanger which is provided along la length of the coil, and the throttling action of the 4thermostat valve is suchthat the spaces between the tins cannot accumulate condensate 4from surrounding air because the flow of water is throttled Suthciently to insure rap-id heating of water in the heat eX- changer to a temperature which is so high that the exchange of heat between the ns and water'does not result in cooling of fins to a temperature at which the deposition of condensate can take place.

The novel features which are considered as characlteristic of the invention are set forth in particular in the appended claims. The improved heating system itself, however, yboth as to its construction and its modeI of operation, together with additional features and advantages thereof, will be best understood upon perusalof the following detailed description of certain specific embodirnents with reference to the accompanying drawings, in which:

FIG. 1 is a somewhat schematic view of a forcedc1rculation hot-water heating system which is constructed in accordance with a first embodiment of the present invention, certain portions of the heating system being shown in section;

FIG. 2 is -a central vertical sec-tion through la throttling device which is utilized in the heating system of FIG.` 1;

FIG. 3 i-s a horizontal section as seen in the direction of arrows from the line IV-lV of FIG. 2;

FIG. 4 is a Vertical section through the thermostat valve of the throttling device a-s seen in the direction of arrows from line 1V-IV of FIG. 2;

FIG. 5 is a schematic view of a modified hot-waterheating system; 1and FIG. 6 is a similar schematic view of a third hot-water heating system.

Referring to FIG. 1, there is shown a hot-Water heating system including a

coil

11, 12 which defines a closed path fora supply of water, a circulating pump 14, a heat exchanger 15 having -fins 15a surrounding a length of the coil, a gas burner 16 which is located beneath and heats the fins 15a, `and heat dissipating elements in the form of radiators 10,v only one such radiator being actually shown in the drawing. The radiator 10 is installed downstream of the heat exchanger but upstream of the pump 14. The flow of fuel to the burner 16 is controlled by a safety device 19 which is responsive to a pressure differential between the interior of the clod-water (return) section 12 and the hot-water section 11 of the coil. Upstream of the pump 14, the return section 12 communicates with an expansion line 13 leading to an expansion tank 13a.

The flow of fuel to the burner 16 is controlled by a normally closed regulating valve 17 which is mounted in a supply conduit 18. This regulating valve 17 is a gas valve of known design and is operated by the safety device 19 which comprises a casing accommodating an actuating element here shown as a deformable diaphragm 20 so as to divide its interior into `

chambers

21, 22. The diaphragm 20 is connected with and serves as a means for moving the valve member 17a of the valve 17 away from its seat 17b. The valve member 17a is biased by a spring 17C. The chamber 21 is connected with the return section 12 by a high-pressure pipe 23 which communicates with the section 12 at the downstream side of the pump 14, and the chamber 22 is connected with a low-pressure pipe 24 leading to the hot-water section 11. The chamber 21 is the high-pressure chamber and the chamber 22 is the low-pressure chamber. When the pump 14 is started, the heat exchanger 15 offers a certain resistance to the flow of water through the coil so that pressure prevailing in the chamber 21 exceeds th-e pressure in the chamber 22. The pressure differential causes the diaphragm 20 to move `the valve member 17a away from the seat 17b and to admit gaseous fuel from the supply conduit 18 into the burner 16. Such fuel is ignited by an automatic igniter device -of any known design, not shown in the drawings.

In -accordance with the presen-t invention, the rate at which Water may circulate through the coil is controlled by a throttling device 25 which is installed in the hotwater section close to and upstream of the point where this section communicates with the low-pressure pipe 24. The throttling device 25 is operative when the valve 17 admits fuel to the burner 16 and when the water temperature in the coil is below a predetermined value. The device 25 lthen insures that the flow of water through the hot-water section 11 is throttled whereby the burner 16 heats a small quantity of water per unit of time. The throttling action of the device 25 is proportional to the temperature of water and decreases in response to rising water temperature. When the entire supply of water in the

coil

11, 12 is heated to a predetermined temperature, the throttling device 25 is fully opened and allows for maximum (normal) circulation of water. In accordance with a preferred embodiment of our invention, the throttling device 25 comprises a thermostat valve which regulates the cross-sectional area of the passage in the hot-Water section 11. `-It will be noted that Ithe device 25 is installed upstream of the point Where the chamber 22 communicates with the section 11 of the coil and upstream of the point where the chamber 22 communicates with the pipe 24.

FIGS. 2 to 4 illustrate the construction of throttling device 25. This device comprises a housing 30 including two open-ended

tubular portions

31, 32. The open lower end of the upper portion 31 is connected to the open upper end of the lower portion 32 by a joint 33 which is llocated in a horizontal plane and supports a thermostat valve 34. The valve 34 comprises an annular valve member 36 which is biased by a resilient element here shown as a helical spring 35. The periphery of the valve member 36 is adjacent to an annular valve seat 38 having an annular flange 37 which is clamped between the

tubular portions

31, 32. When the water temperature in the hot-water section 11 of the coil descends to or below a predetermined minimum value, the spring maintains the valve member 36 in the axial position of FIG. 4 so that the valve member 36 and the seat 38 define between themselves an annular gap 39 which allows a minimum quantity of water to flow from the heat exchanger 15 to the radiator 10. The fiange 37 is conneet-ed with a lower carrier or yoke 40 and with an upper carrier or yoke 41. These yokes partially enclose the valve member 36 and the yoke 40 carries an upwardly extending projection or pin 42 secured thereto by a nut 42a. The pin 42 is slidable in an aperture provided in the bottom wall of a jacket here shown as a cylinder 43, and this cylinder is formed with a circumferential shoulder 44 `for Ithe valve member 36. The upper end portion of the cylinder 43 extends through 4and beyond an aperture provided in the median portion of the yoke 41, and the internal space of the cylinder accommodates an annular sealing member 45 which is adjacent to the apertured bottom wall and forms a fluid-tight seal around the pin 42. The upper por-tion of the internal space in the cylinder 43 is filled with a material 46 which expands in response to a rise in temperature Iof the cylinder such as is brought about by changes in the temperature of water which flows in the hot-water section 11. The upper leg 11a of this hot-water section is connected to the cylindrical wall of the upper tubular portion 31 and the lower leg of the section 11 comprises a nipple 11b which i-s secured to the bottom wall `of the lower tubular portion 32 so that water flowing through and beyond the heat exchanger 15 may enter the upper portion 31 to flow around the cylinder 43, through the gap 39, through the lower portion 32 and into the nipple 11b.

The material 46 has a predetermined coefficient of expansion and allows the valve member 36 to remain in the lower end position of FIG. 4 when the Water tempera-ture in the section 11 reaches or descends below a predetermined minimum value. The valve member,36 is then held in such lower end position by the spring 35 which forces the pin 42 to penetrate into the material 46 by operating between the upper yoke 41 and the valve member, i.e., between the yoke 41 and the shoulder 44 of the cylinder 43. The latter is slidable in the centrally located aperture of the yoke 41.

When the temperature -of water flowing through the section 11 begins to rise, the material 46 expands gradually and expels a portion of the pin 42 from the internal space Iof the cylinder 43 whereby the cylinder begins to move upwardly, as viewed in FIG. 4, and the cross-sectional area of the gap 39 between the valve member 36 and valve seat 38 increases proportionally so that the water may circulate at a higher rate. The expansion coefficient of the material 46 is such that Ithe bias of the spring 35 is overcome only at the time the temperature of water flowing in the section 11 rises above a predetermined minimum value. Also, in the initial stage of expansion of the material 46, the cross-sectional area of the gap 39 preferably remains unchanged or increases very little (see FIG. 6 which shows that the peripheral portion of the valve member consists of a short cylinder which is surrounded by a concentric cylindrical portion of the valve seat 38 so that the cross-sectional area of the gap 39 remains unchanged as long as the cylindrical portion of the valve member 36 is actually surrounded by the cylindrical portion of the valve seat). In other words, 4the cross-sectional area of the gap 39 begins to increase gradually when the temperature of w-ater in the section 11 rises to a value which is necessary to bring about a predetermined compression (shortening) of the spring 35 so that the cylindrical portion of the valve member 36 rises to a level above Ithe cylindrical portion of the valve seat 38.

It will be seen that the 4throttling device 25 allows for circulation of a smaller quantity of water when the water temperature is below a preselected value whereby the water filling that length of the coil which is surrounded by the Iins a of the heat exchanger 15 remains in longerlasting heat-exchanging contact with the tins 15a and is rapidly heated to a temperature at which the device responds to allow for increased circulation of water through the coil. The thermostat valve 34 causes the throttling device 25 to open fully at the time the water temperature reaches or rises above a predetermined maximum value.

It is a rather simple procedure to selec-t the minimum cross-sectional area of the gap 39 and the material 46 in such a way that water circulating in the

coil

11, 12 may be heated without causing any (or by causing negligible) deposition of condensate on the fins 15a. As a rule, the valve member 36 will be biased to the position of FIG. 6 whenever they flow of gaseous fuel to the burner 16 is shut off and whenever the water temperature drops below a predetermined minimum value so that the abovedescribed operation begins as soon `as -the valve 17 admit-s fuel t-o the burner 16 4and the latter begins to heat the ns 15a.

FIG. 5 illustrates a somewhat modified` hot-water heating system wherein the high-pressure chamber 21 of the control device 19 is connected to a high-pressure pipe 223 leading to the hot-water section 11 at a point upstream of the throttling device 25. The low-pressure pipe 24 communicates with the throat portion of `a Venturi 26 which is provided in the sec-tion 11 downstream of the throttling device 25, i.e., the inlet of the Venturi receives water which has passed through the gap 39 of the thermos-tat valve 34 in the housing 30 of the device 25. In FIG. 5 the Venturi 26 produces the pressure differential which is necessary to keep the gas valve 17 in open position.

It will be seen that the throttling device is again located upstream of the point where the chamber 22 communicates with -the pipe 24.

FIG. 6 illustrates a third hot-water heating system which differentiates from the systems of FIGS. 4 and 5 in that the lhigh-pressure pipe 323 connects the chamber 21 with the section 11 at a point downstream of the point where the pipe 24 communicates with this section 11. The pres-l sure differential necessary to operate the control device 19 is produced mainly by a Venturi 326 which is provided in the section 11 and whose throat portion communicates with the intake end of the pipe 24. A modified throttling device 27 is located upstream of the Venturi 326 and cooperates therewith to regulate'the flow of water through the section 11. This throttlingdevice 27 comprises a thermostat which controls the axial position of a needle-shaped valve member 27a extending into and eyond the inlet of the Venturi 326. Changes in axial position of the valve member 27a will bring about changes in the cross-sectional area of the annular orifice in the Venturi 326 so that the rate of water How may be regulated in .a manner analog-ous to that described in connection with FIGS. l to 4. The thermostat which regulates the axial position of the valve member 27a comprises Va sensing element 27b which is in contact with water owing toward the Venturi 326.

Otherwise, the construction of the systems shown in 6 FIGS. 5 and 6 corresponds exactly to that of the system shown in FIG. 1.

It will be readily understood that, even though the drawings illustrate hot-water heating systems whose burners operate with gaseous fuel, such burners may be replaced by other types of burners which utilize liquid or solid fuel. Also, while the drawings show heating systems wherein the regulating valve 17 is controlled by a safety device 19 which opens the valve 17 in response to a differential in water pressure, this safety device 19 may be replaced by other types of safety devices, for example, by a magnetic valve which regulates the admission of fuel in response to impulses furnished by a thermostat or in response to operation of the circulating pump 14. All that counts is to provide a thermostatic-ally regulated throttling device which controls the rate of water circulation in such a way that the rate of flow depends on the temperature of water so as to prevent the deposition of condensate on the heat exchanger whereby the spaces between the fins 15 remain free and allow for eicient exchange of heat between the fins and the products of combustion or llames of the burner 16. This is due to the fact that small quantities of water which circulate through the heat exchanger 15 when the throttling device reduces the rate of flow undergo a very intensive heating action and the water temperature rises rapidly. Consequently, the fins 15a are maintained at a temperature which is high enough to prevent deposition of condensate. As soon as the deposition of condensate is prevented, there is no danger that the spaces between the iins 15a would become clogged.

FIGS. l, 5 and 6 show that, when the hot-water heating system comprises a safety device 19, the throttling

device

25 or 27 is preferably positioned in that section of the coil in which the pressure differential exists, i.e., in the hot-water section 11, whereby the throttling device may be installed upstream of the low-pressure pipe 24 but downstream of the high-pressure pipe 23 or 223 (FIGS. l and 5) or upstream of the pipes 24, 323 (FIG. 6). In FIG. l, the pressure differential is produced solely by the Vresistance to water flow which is offered by the heat exchanger 15. In FIG. 5, such pressure differential is produced mainly by the Venturi 26, and in FIG. 6 ghe pressure differential is produced mainly by the Venturi Another very important advantage of our hot-water heating system is that the system is practically'noiseless which is attributable to the fact that the throttling

device

25 or 27 allows water to circulate at a rate which increases in proportion to rising water temperature. In many conventional hot-water heating systems, water which is overheated in the heat exchanger will produce a hissing sound which is unpleasant to human ears.

Furthermore, the throttling

device

25 or 27 insures that the resistance to ow is rather high when the water temperature is low whereby the gas valve 17 may open in response to low water pressure and remains open when the resistance which the throttling device olfers to ow of water decreases at elevated temperatures. The throttling device is reliable in operation and requires little attention. Also, by effecting certain minor adjustments ad system utilizing our improved throttling device may be used with advantage in heating systems which operate with boiling water.

The material 46r used in the cylinder 43 of the throttling device 25 may be a wax like product.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specic aspects of this invention and, therefore, such adaptations should and are intended to he comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a hot-water heating system, in combination, a coil defining an endless path for a supply of water; pump means for circulating the water in said coil; .a burner arranged to heat the water in said coil; a conduit for suppling fuel to said burner; a normally closed regulating valve provided in said conduit; means for producing a pressu-re differential in two spaced portions of said coil when the water is circulated by said pum-p means; a safety device comprising a pair of water-filled chambers each communicating with one of said spaced portions of the coil so that the water pressure in one of said chambers exceeds the water pressure in the other chamber, and actuating means operatively connected with and arranged to open said regulating valve in response to such pressure differential in said chambers; and a throttling device comprising a thermostat Valve mounted in said coil upstream ofthe point where said other chamber communicates with the corresponding portion of said coil and arranged to throttle the ow of water at least when the water temperature in said coil is below a predetermined value.

2. In a hot-water heating system, in combination, a coil defining an endless path for a supply of water; pump means for circulating the water in said coil; a burner arranged to heat the water -in said coil; a conduit for supplying fuel to said burner; a normally closed regulating valve provided in said conduit; means for producing a pressure `differential in two spaced portions of said coil when the water is circulated by said pump means; a safety de-vice comprising a pair of water-filled chambers eac-h communicating with one of said spaced portions of the coil so that the water pressure in one of said chambers exceeds the water pressure in the other chamber, and actuating means operatively connected with and arranged to open said regulating valve in response to such pressure differential in said chambers; and a throttling device comprising a thermostat valve mounted in said coil between said spaced portions thereof and arranged to throttle the ow of water at least lwhen the weiter temperature in said coil is below a predetermined va ue.

3. A structure as set forth in claim 2, wherein that one of said spaced portions which communicates with said other chamber is located downstream of the other spaced portion.

v74. In a hot-water heating system, in combination, a coil defining an endless path for a supply of water; pump means for circulating the water in said coil; a burner arranged to heat the water in said coil; a conduit for supp-lying fuel to said burner; a normally closed regulating valve provided in said conduit; means including a Venturi for producing a pressure differential in two spaced portions of said coil when the water is circulated by said pump means whereby .the portion containing water whose pressure is higher is located upstream of said Venturi; a safety device comprising a pair of water-filled chambers each communicating with one of said spaced portions of the coil so that the water pressure in that one of said chambers which is connected with the portion located upstream of said Venturi exceeds the water pressure in the other chamber, and actuating means operatively connected with and arranged to open said regulating valve in response to such pressure differential in said chambers; and a throttling device comprising a thermostat valve mounted in .said coil upstream of said Venturi and downstream of the portion containing water whose pressure is higher, said thermostat valve being arranged to throttle `the flow of water vat least when the water temperature in said coil is below a predetermined value.

5. A structure as set forth in claim 4, wherein said Venturi comprises a throat portion and wherein said other chamber communicates with said throat portion.

6. In a hot-water heating system, in combination, a coil defining an endless path for a supply of water; pump means for circulating the water in said coil; a burner arranged to heat the water .in said coil; a conduit for supplying fuel to said burner; a normally closed regulating valve provided in said conduit; means including a Venturi for producing la pressure differential in two spaced portions of said coil when the water is circulated by said pump means whereby the portion lcontaining water whose pressure is higher is located downstream of the other portion and downstream of said Venturi; a safety device comprising a pair of water-filled chambers each communicating with one of said spaced portionsof'the coil whereby the water pressure in that one of said chambers which is connected with the portion containing water whose pressure is higher exceeds the Water pressure in the other chamber, and actuating means operatively connected with and arranged to open said regul-ating valve in response to such pressure differential in said chambers; and a throttling device comprising a thermostat valve mounted in said coil upstream of said Venturi, said thermostat valve having a reciprocable valve member adjacent to said Venturi and a temperature-responsive sensing element pro-vided in said coil and operatively connected ywith said valve member to reciprocate the latter in response to changes in water temperature so that said Valve member throttle-s the flow of water through said Venturi at least when the water temperature in said coil is -below a predetermined value.

7. A .structure as set lforth in claim 6, wherein said valve member is a needle which extends through the inlet of said Venturi.

8. A structure as set forth in claim 6, wherein said Venturi comprises a .throat portion and the `other chamber communicates with said throat portion.

9. In a hot-water heating system, in combination, a coil defining an endless path yfor a supply of water; pump means yfor circulating the water in said coil; a burner arranged to heat the water in said coil; a conduit for supplying fuel to said burner; a normally closed regulating valve provided in said conduit; means for producing a pressure differential in two spaced portions of said coil when the water is circulated by said pump means; a safety device comprising a pair of water-filled chambers each communicating with one of said spaced portions of the coil so that the water pressure in one of said chambers exceeds the water pressure in the other chamber, and actuating means operatively connected with and lar-ranged to open said regulating valve in response to such pressure differential in said chambers; and a throttling device comprising a housing having two tubular housing portions connected in said coil upstream of the point where said other chamber communicates with the corresponding portion of said coil so that the circulating water flows through said housing portions, said housing portions having open ends adjacent to each other, a joint sealingly connecting said open ends with each other, and a thermoi stat valve provided in said lhousing and including an annular seat secured to said joint, a valve member reciprocable in and defining with -said seat -an annular gap of variable cross-sectional area, and means responsive to water temperat-ure in said housing and operatively connected with I-said valve member to reciprocate :the valve member with reference to said seat and to increase the cross-sectional area of sa-id gap when `the water temperature in said yhousing rises above a predetermined value.

'10. A structure as set forth in claim 9, wherein said thermostat valve yfu-rther comprises resilient mean-s for biasing said valve member to a position in which the cross-sectional area of said gap is reduced -to a minimum when the water temperature drops to said predetermined value.

il. In a hot-water heating system, in combination, a coil defining an endless path for a supply of water; pump means for circulating the water in said coil; a heat exchanger having fins exposed to a humidity containing atmosphere, said tins surrounding a length of the coil downstream of .said pump means; a burner arranged to heat said ns whereby the heat exchanger 'heats the water in said coil Iand said iins exhibit a tendency to collect conde-nsate from the surrounding -humidity containing atmosphere -when the water temperature in said length of coil is below a predetermined value; heat-dissipating means provided in said coil downstream of said heat exchanger but upstream of said pump means; a throttling v-alve for regulating the rate of water flow through said coil, said throttling valve provided in said coil adjacent to and downstream of said heat exchanger but upstream of said heat dissipating means; and thermostatic actuating means dependent upon the water temperature in the region of said throttling valve adjacent to and downstream of said heat exchanger -for reducing the rate of water flow, when the water temperature in the region of said ylength of the coil drops below said predetermined value below which condensate would tend to collect on said fins, so that the ow of water through said length of co-il is slowed down whereby the water temperature in said length of coil rapidly rises above said predetermined value to at least reduce the accumulation of condensate on said iins.

1'2. In a hot-water 'heating system, in combination, a coil defining an endless path for a supply of water; pump means lfor circulating the water in said coil; a heat exchanger having tins exposed to a humidity containing atmosphere, said ins surrounding a length of the coil downstream of said pump means; a burner arranged to heat said ns whereby the heat exchanger heats the water in said coil and said fin-s exhibit a tendency to collect condensate from the surrounding humidity containing atmosphere when the water temperature in said length -of coil is below a pre-determined value; a throttling Val-ve for regulating the rate of water ow through said coil, said throttling valve provided in said coil adjacent to and downstream of said heat exchanger but upstream of said pump means; and thermostatic actuating means dependent upon the water temperature in the region of said throttling valve adjacent to and downstream of sai-d heat exchanger =for reducing the rate of huid flow when -the water temperature in the `region of said length of the coil drops below said predetermined value below which condensate would tend to collect on said iins, so that the tow of water through said length of coil is slowed down whereby the water temperature in said length of coil rapidly rises above said ipredetermined value to at least reduce the accumulation of condensate on said ns.

13. In a hot-water heating system, in combination, a coil deiining an endless path `fora supply of water; pump means for circulating the water in said coil; a heat exchanger having fins surrounding a length of the coil downstream of said pump means; a burner arranged to heat said hns whereby the heat exchanger heats the water in said coil and said ns exhibit a tendency to collect condensate lfrom the surrounding air when the water temperature in said coil is below a predetermined value; a supply conduit arranged to supply fuel to said burner; a normally close-d regulating valve provided in said supply conduit; a safety device for opening said regulating valve in response to circulation of water in said coil; and a throttling device for regulating the rate of water flow through said coil, said throttling device comprising a thermostat Valve provided in said coil downstream of said heat exchanger but upstream of said pump means and arrange-d to reduce the rate of uid flow, at least when the water temperature is below said 'predetermined value, so that the water temperature in said length of coil rapidly rises above said predetermined value to at least reduce the accumulation of condensate on said `tins.

14. A structure as set tforth in claim 13, wherein said safety device is responsive to a pressure differential in two spaced portions of said coil and wherein such pressure differenti-al is produced at least in part by the resistance offered by said heat exchanger to the circulation of water through said length of coil.

15. In a hot-water heating system, in combination, a coil dening an endless path `for a supply of water; pump means for circulating the water in said coil; a heat exchanger having ns surrounding a length of the coil downstream of said pump means; a burner arranged to heat said tins whereby the heat exchanger heats the water in said coil and said Ifins exhibit a tendency to collect condensate from the surrounding air [when the water temperature in said coil is below a predetermined value; heat-dissipating means provided in said coil downstream of said heat exchanger Ibut upstream ot said pump means; and a throttling device yfor regulating the lrate of water flow through said coil, said throttling device comprising a thermostat valve provided in said coil downstream of said heat exchanger but upstream of said heat-dissipating means and arranged to reduce the rate of uid flow, at least when the water temperature is below said predetermined value, so that the water temperature in said length of coil rapidly rises above said predetermined value to at least reduce the accumulation of condensate on said fins, said thermostat valve comprising a Venturi provided in said coil and having an inlet, a valve member reciprocably extending through the inlet of said Venturi to thereby regulate the rate of water liow through the Venturi, and a temperature-responsive sensing element pro-vided in said coil and operatively connected to said valve member to reduce the rate of water how through said Venturi when the 'water temperature descends to said predetermined value.

16. In a heating system, in combination, a coil dening an endless path for a supply of fluid, a heat exchanger and at least one heat dissipating element provided in said coil; burner means arranged to heat said heat exchanger whereby the latter heats the fluid; means for circulating the uid in said coil; conduit means connected with Iand arranged to supply fuel to said burner means; a normally closed regulating valve provided in said conduit means; a safety device for opening said regulating valve in response to a pressure differential in two spaced portions of said coil; :and an adjustable throttling device Afor regulating the rate at which the fluid may circulate in said coil, said throttling device comprising a thermostat valve mounted in said coil and arranged to throttle the flow of duid at least when the huid temperature in said coil remains below a predetermined value.

17. A struct-ure as set forth in claim `16, wherein said heat exchanger comprises at least one package of flins dening between themselves spaces which collect condensate from the surrounding air when the temperature of `fluid in said coil drops to said predetermined value, said throttling device being arranged to prevent such accumulations of condensate in said spaces by throttling the ow of huid sutiiciently to insure tha-t huid contained in said heat exchanger is rapidly heated to above said predetermined temperature.

References Cited by the Examiner UNITED STATES PATENTS 1,061,635 5/1913 Ross 237-8 2,194,805 3/ 1940 Moore 237-8 2,340,844 2/ 1944 -Dillman 237-8 2,981,477 4/ 1961 Salmon 236-34 3,201,045 8/ 1965 Davidson et al 237-8 FOREIGN PATENTS 1,201,596 7/1959 France.

EDWARD I. MICHAEL, Primary Examiner.

Claims

1. IN A HOT-WATER HEATING SYSTEM, IN COMBINATION, A COIL DEFINING AN ENDLESS PATH FOR A SUPPLY OF WATER; PUMP MEANS FOR CIRCULATING THE WATER IN SAID COIL; A BURNER ARRANGED TO HEAT THE WATER IN SAID COIL; A CONDUIT FOR SUPPLING FUEL TO SAID BURNER; A NORMALLY CLOSED REGULATING VALVE PROVIDED IN SAID CONDUIT; MEANS FOR PRODUCING A PRESSURE DIFFERENTIAL IN TWO SPACED PORTIONS OF SAID COIL WHEN THE WATER IS CIRCULATED BY SAID PUMP MEANS; A SAFETY DEVICE COMPRISING A PAIR OF WATER-FILLED CHAMBERS EACH COMMUNICATING WITH ONE ONE OF SAID SPACED PORTIONS OF THE COIL SO THAT THE WATER PRESSURE IN ONE OF SAID CHAMBERS EXCEEDS THE WATER PRESSURE IN THE OTHER CHAMBER, AND ACTUATING MEANS OPERATIVELY CONNECTED WITH AND ARRANGED TO OPEN SAID REGULATING VALVE IN RESPONSE TO SUCH PRESSURE DIFFERENTIAL IN SAID CHAMBERS; AND A THROTTLING DEVICE COMPRISING A THERMOSTAT VALVE MOUNTED IN SAID COIL UPSTREAM OF THE POINT WHERE SAID OTHER CHAMBER COMMUNICATES WITH THE CORRESPONDING PORTION OF SAID COIL AND ARRANGED TO THROTTLE THE FLOW OF WATER AT LEAST WHEN THE WATER TEMPERATURE IN SAID COIL IS BELOW A PREDETERMINED VALVE.