Flow heater

2,808,034

J. CERNY

FLOW HEATER

Oct. 1, 1957

Filed May 25, 1954

Sheets-Sheet 1

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INVENTOR.

^OSep C-ER.ri'/

<img file="US2808034A_D0002.tif" />

J. CERNY

FLOW HEATER

Oct 1, 1957

Filed May 25, 19542,808,034

Sheets-Sheet 2

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INVENTOR.

J'oS.ef C^Rriy

BY

2,808,034

Patented Oct. 1, 1957

United States Patent Office effected by means of the heat exchanger within the heating-steam or hot-water reservoir whereas the room heating installation with its delivery and return lines may be connected in parallel to that cycle. A further measure 5 according to the invention and of essential significance for the function of the flow heater resides in that the heat exchanger lies in the heating-steam or hot-water reservoir between the inlet for the steam or hot water and its return line and the delivery line of the room heating 10 installation is attached to the heating-steam or hot-water reservoir at a distance from the heating-steam or hotwater inlet, for the interposition of part of the heat exchanger serving as a temperature-reducing resistance, and that close to or directly at the fresh-water inlet of 15 the heat exchanger and the beginning of the return line for the hot water a thermostat is arranged, which operates a control member controlling the fuel supply to the burner in dependence on the temperature variation in the inlet range of the cold water and effective immediately 20 when a temperature drop in the heating-steam or hotwater reservoir results from a taking of water for consumption, in order to compensate that temperature drop by setting the heating to a higher energy stage. Thus a heating appliance for warm water and water for con25 sumption is provided, which automatically adjusts itself and very flexibly responds to all conditions of demand and which utilizes the expended heat energy in a degree not hitherto achieved.

In the drawing the invention is shown in an illustra30 tive embodiment in its essential features in Fig. 1 in conjunction with the use of a warm-water reservoir, in vertical section, and in Fig. 2 in a side view of the return-line side, with the casing and jacket in section. Figs. 3 and 4 show the boiler and burner in plan, according to hori35 zontal sections C—D and E—F, respectively, of Fig. 5. Fig. 5 shows the arrangement of the pipe coil in conjunction with the use of a steam reservoir.

The flow heater serving for preparing warm water and for heating water for consumption has a radiator-type 40 heater, which consists, e. g., of six heating elements 1 having small flow cross sections and large heat absorbing surfaces. Each of the heating elements 1 consists of a flat casting, which is divided, e. g., by five vertically extending passage slots 2, into six water carrying conduits 45 3, which open at top and bottom into common collecting spaces. Each of said collecting spaces has a central connection fitting 4 and 5, respectively. These heating elements 1 are connected in parallel in a hot-water flow cycle, their lower connection fittings 4 being firmly and 50 tightly fixed in direct succession on a pipe length 7 directly connected to the return pipe 6, and their upper connection fittings 5 being firmly and tightly fixed in a similar manner on a delivery pipe 8. The pipe length 7 and the delivery pipe 8 have radial bores through which they 55 are in flow-communication with the cavities of the heating elements 1. The delivery pipe 8 is bent upwardly and opens at the top into the end of a hot-water reservoir 9 effective as a heat accumulator. That hot-water reservoir consists of an outer shell 9 and an inner shell 10 60 of much smaller diameter, which encloses a water-free cavity 11 and together with the outer shell 9 forms a reservoir space 12 of annular cross section, into which flows the hot water from the delivery pipe 8. At the other end of the hot-water reservoir 9, 12 the outlet pipe ⁶⁵ 13 is attached in the form of a fork continued in a single pipe which opens into one end of the pipe length 7 connected to the return pipe 6 to complete the closed hotwater cycle.

The return pipe 6 of the hot-water cycle lies horizontally in the same plane as the burner tube 14 just above the supporting base of the flow heater. The burner tube 14 is forked and intended, e. g., for gas firing.

2,808,034

FLOW HEATER

Josef Cerny, Vienna, Austria, assignor to Fa. Gas-, Wasser- nnd Elektrische Anlagen Swatek &amp; Cerny, Vienna, Austria

Application May 25, 1954, Serial No. 432,259

Claims priority, application Austria June 9,1953

Claims. (Cl. 122—32)

The invention relates to a flow heater which can be utilized, if desired, also as a hot-water or stem heating appliance, with a boiler which is heated by a gas- or oilburning device, if desired also by a pulverized-coal burning device, and whose counterflow apparatus (reservoir) is arranged together with the boiler in a hot-water cycle, which either heats a heat exchanger, provided in the counterflow apparatus, for water for consumption to be taken as required, or supplies warm water to one or several warm-water radiators which serve for room heating and which with their supply and discharge lines are connected to the delivery and return lines of the hot-water cycle and can be turned on and off as required. In those known flow heaters the reservoir is connected by conduit pipes to the boiler and is not heated. The heat transfer to the heat exchanger carrying the water for consumption is effected by the hot water contained in the reservoir, which is supplied from the boiler through freely extending lines. In many cases a pump is used to maintain the circulation of hot water. Depending on its direction of rotation that pump conveys the hot water from the boiler either for heating the heat exchanger or for feeding the warm-water heating installation. Flow heaters are known in which the hot-water reservoir and the counterflow apparatus are combined in a single set. In that case too the counterflow apparatus is not swept by the heating gases but is only flown through by the hot water; thus it is not heated additionally. The absence of an additional heating of the reservoir or counterflow apparatus has the result that when relatively large quantities of water for consumption are taken the heat exchanger takes from the reservoir such an amount of heat energy that after the water for consumption has been taken the warm-water heating system returns only very slowly to the previously adjusted heat output.

For this reason the main idea underlying the invention is to utilize the heat of the boiler primarily for heating the counterflow apparatus or reservoir and thus to increase the heating effect to a maximum not achieved so far, and further to combine the heating of the water for consumption and the room heating by means of the counterflow apparatus in such a manner that the heating of the water for consumption and the room heating operate independently of each other but also simultaneously with the closest flexible adaptation possible regarding the respective conditions of demand, without requiring for this purpose special shut-off means or drive means such as pumps or the like.

According to the invention this idea is carried into effect by arranging the boiler, consisting of hollow heating elements having a large heat absorbing surface and small flow cross section, in the heating-gas stream in series with a heating-steam or hot-water reservoir which functions as a counterflow apparatus and contains the heat exchanger for heating the water for consumption, the boiler and the heating-steam or hot-water reservoir being included in a closed cycle of the steam or hot water, in which cycle the heating of the water for consumption is

2,808,034

By the pipe 15 it is connected through a gas-burner cock 16 to the gas pressure control 17, which through the pipe length 18 is connected to the known safety cock 20 having a push button 19 and possessing the pilot burner 21 burning with a small flame and enabling the supervi- 5 sion of the supply of gas from the supply line 22.

To avoid the formation of water of condensation the heater consisting of the heating elements 1, as well as the hot-water reservoir 9, 12 are arranged almost directly one above the other in a firebox space 23, which being 10 enclosed by a downwardly opening casing 24, surrounds the hot-water reservoir 9 with a slight clearance and has at the top an offtake 25. That casing 24 is surrounded with a clearance by a jacket 36, which permits scavenging air to flow from below through the smoke flue 37 and 15 thus cools the casing 24 from the outside. That firebox casing 24 extends down to a horizontal plane just above the burner tube 14 to conduct the combustion gases upwardly along the heater 1 and the hot-water reservoir 9. To achieve a good utilization of the hot combustion gases, 20 the heating elements 1 have in their upper part below the connection fittings 5 horizontal baffles 26 in a rooflike arrangement, which guide the heating gases from the interspace between two heating elements through the oblong slots 2 into the adjacent interspace. Thus the heat- 25 ing gases are somewhat dammed up and deflected in the upper portion of the heating elements and are thus forced to deliver the largest possible part of their heat to the heater.

For the operation of a warm-water heating installation 30 having several radiators for room heating, the hot-water reservoir is provided at its top with a riser pipe 27, an expansion vessel 28 and an overflow pipe 29 connected thereto. The supply line 30 to the radiators (not shown) is connected to the riser pipe 27. The return line (not ³⁵shown) from the radiators opens at the bottom into the return pipe 6.

A pipe coil 31 arranged in the hot-water reservoir 9, 12 serves for heating water for consumption. The inlet 32 to and the outlet 33 from that coil are provided at that 40 reservoir end wall .which is adjacent to the outlet 13 for hot water from the reservoir 9. That pipe coil 31 is always maintained at the temperature desired at a given time, e. g. 80 deg. C., by the hot water in the reservoir 9, 12, and can deliver at any time hot water for consumption, . _re. g. for cooking and washing purposes. That pipe coil ^4t&gt;31 is dimensioned in cross section and length so as to occupy a substantial part of the hot-water reservoir space, at least more than half thereof, to be able quickly to transfer the heat from the hot water of the reservoir to the fresh water in the pipe space.

According to Fig. 5 the hot-water reservoir 9, 12 of annular cross section may be replaced by a steam reservoir 34, in which the pipe coil 31 for the water for consumption is partly immersed into the hot reservoir water .-.and partly extends through the steam space, from which ⁰⁰the steam can flow through the riser pipe 27 into the heating line to the radiators.

It should be emphasized above all that the entire plant is controlled by a control member under control of a _f0thermostat 35 arranged in the hot-water reservoir 9 or “ low-pressure steam reservoir 34. That thermostat 35 is incorporated in the hot-water reservoir so as to be easily removable and adjacent to the cold-water inlet to pipe coil 31 and the reservoir outlet 13 and for this reason _e5is temperature-controlled by the inflowing cold water in the pipe, coil and by the cooled-down hot water of the reservoir. Where a hot-water reservoir is used, according to Fig. 1, the thermostat 35 is functionally connected through a control line 38 to a gas pressure control 17 70 of the gas burner 14 and controls the gas pressure control 17 in dependence on the degree to which the thermostat is cooled by the fresh water and/or the outflowing reservoir water. Where a low-pressure steam reservoir 34 is employed (Fig. 5), the thermostat 35 will influence 75 under the same conditions the steam pressure control (not shown) which is also connected through a control line to the gas pressure control 17 and operates the same to throttle it or to effect a greater or smaller increase of the heating effect of the gas firing. The location of the thermostat 35 in the hot-water or steam reservoir is of eminent importance for the ability of the flow heater quickly to respond to the respective conditions of demand for water consumption and room heating.

This means that the flow heater is capable of regulating itself fully automatically and to adapt automatically with highest economic efficiency to the heat consumption resulting at any time from the heating of water for consumption and from room heating, without being dependent on the pressure conditions in the local water supply.

The flow heater has the following mode of operation: It may be assumed that the heater 1 and the hotwater reservoir 9, 12 be filled with water and the burner be in operation. The heating gases flow within the firebox casing 24 upwardly along the heating elements 1 until they are deflected by the baffles 26 through the passages slots 2 into the respective adjacent interspace and can escape around the reservoir shell outwardly through the offtake 25 into the flue 37. The heat absorbed by the heating elements 1 is transferred to the water which flows through the conduits 3 and in the form of hot water or steam flows through the delivery pipe 8 to the hot-water reservoir 9, 12 or steam reservoir 34. Here the hot fluid brings the pipe coil 31 with its contents of water for consumption to the same temperature as the water contained in the reservoir 9, 12. When the reservoir water has been cooled because heated water for consumption has been taken from the pipe coil 31, that cooling is utilized by the thermostat 35 in the reservoir space 12 for controlling the gas pressure control 17, which is set to a greater heat output; that heat output is reduced immediately when the normal temperature has been reached in the reservoir. The heat output is regulated in the same way when a radiator is turned on which serves for room heating and is connected to the supply line 30. For this reason the room heating and the preparation of hot water for consumption can be effected with this flow heater simultaneously though completely independently of each other. It is of eminent importance that the flow heater according to the invention, owing to its design, is independent of the pressure conditions in the local water supply and for this reason can be reduced down to a minimum from a normal heat output without need for giving regard to the pressure conditions in the water supply. Thus it is achieved for the first time that a flow heater of relatively small size but high heat transfer rate can be used for winter and summer operation without requiring changes in the flow system of the hot-water cycle or in the burner system. Whereas in winter operation the riser pipe and the following supply line 30 supply hot water to the radiators for room heating, the riser pipe 27 will function in summer operation only as an expansion tube with overflow vessel and the hot-water reservoir 9, 12 will serve only for heating the water for consumption, which flows through the pipe coil 21 as required.

In addition, the heat output can be reduced or increased by a subdivision of the heating elements 1 into element groups that can be connected and disconnected. In order to increase the heating effect with unchanged reservoir 9, 12, it is possible to connect additionally instead of one group of heating elements a plurality of element groups of the same heat output and connected in parallel in the hot-water cycle.