WO1993012389A1

WO1993012389A1 - Quick operating heat exchanger device

Info

Publication number: WO1993012389A1
Application number: PCT/IT1992/000156
Authority: WO
Inventors: Giampaolo Bettelli
Original assignee: Cts S.R.L.
Priority date: 1991-12-09
Filing date: 1992-12-04
Publication date: 1993-06-24
Also published as: ITVR910107A1; ITVR910107A0; EP0640200A1; IT1253145B

Abstract

This heat exchanger comprises a pair of tubular containers (3, 7) adjacent to each other and connected by one end, suitable for containing a first fluid which is inlet at a predetermined pressure. Furthermore, each one of the containers houses a circuit (4, 5) in which a second fluid flows, in a direction which is generally in countercurrent in respect of the flowing direction of said first fluid. Both ends of the containers are tightly sealed by means of a suitable cover, of which the head cover (1) comprises the inlet and outlet connectors of both fluids, and the bottom cover (2) comprises the connectors by means of which the fluids pass from one tubular container to the other one.

Description

QUICK OPERATING HEAT EXCHANGER DEVICE * * * * *

TECHNICAL FIELD

The present invention relates to a quick operating heat exchanger device.

More particularly, the present invention relates to a heat exchanger device having a relatively large surface of thermal exchange allowing a quick thermal exchange between two fluids to be carried out, thereby keeping the loss of pressure at a very low level.

The invention may be maily applied in the field of thermo-mechanical industry.

BACKGROUND ART

The known heat exchangers are devices which are normally used in various hydraulic circuits (e.g. for producing hot water for sanitary an heating use by means of a boiler or a tele-heating network, or in cooperation with heat pumps, systems for cooling induction furnaces, co-generation systems etc. ), and inside of refri erat in /heat ing machines.

By way of example, tube-nest heat exchangers are known, in which the tube nest may assume various configurations inside of the device, in accordance with design requirements also known are plate-type heat exchangers, which are formed by a stack of corrugated plates superimposed to each other in order to form circuits for heat exchange between two different fluids, which are generally flowing in countercurrent .

All known heat exchangers involve disadvantages and drawbacks which are essentially due to the fact that the loss of pressure of the fluids are, in operation, relatively high; consequently, these exchangers need high-power pumps and their operation causes a relatively high energetic consumption.

Furthermore, all known heat exchangers are generally delivered in different dimensions in accordance with the required thermal exchange energy, and they are not formed by modular and/or composable elements.

As a consequence, a large series of different types of heat exchanger has to be produced in order to fulfil

10 all the different possible design requirements, and the production costs feel this effect.

Document DE-A-2,236, 954 discloses a heat exchanger characterised by a large thermal exchange surface and by a low speed. - _ The fluid circulating into this exchanger does not contact the whole thermal exchange surface, but only the central portion thereof; the apparatus may not then achieve good performances.

Document EP-A-0,057,850 discloses an apparatus 0 constituted by a pair of heat exchanger which are connected in parallel, and therefore the water flow is distributed in parallel over said exchangers.

The water flow is not forced, and then the water amy flow only in the inner part of the serpentine. 5 As a consequence, this apparatus may only be used as water collector.

Document DE-U-8, 912, 339 discloses a heat exchanger in which the primary fluid flows in the central portion of the exchanger. 0 The secondary fluid does not flow countercurrent in respect of the water fluid, as it may be seen in fig. 1 of said DE document; on the contrary, the water fluid is lateral, and the exchanger has an overall low performance.

DESCRIPTION OF THE INVENTION

The present invention aims to obviate to the disadvantages and drawbacks mentioned above, and to provide for a device for heat exchanging between two fluids which features a great exchange speed, low losses of pressure, and which is at the same time provided with a modular and/or composable structure.

This is achieved by a heat exchanger device having the features disclosed in claim 1.

The dependent claims describe advantageous forms of embodiment of the invention.

The quick-operating heat exchanger device according to the present invention may generally be used inside of any type of hydraulic circuit for the most different kinds of application, in cooperation with any machine suitable for producing thermal or frigorific energy.

At the same time, the heat exchanger according to the invention allows a quick thermal exhange with low losses of pressure to be carried out between any kind of fluids, e.g. water/gas, water/oil, oil/oil, glycol /water , gas/gas, water/water, etc. .

According to a form of embodiment, the heat exchanger according to the invention comprises a pair of tubular containers adjacent to each other and connected by one end, suitable for containing a first fluid which is inlet at a predetermined pressure.

Furthermore, each one of the containers houses a circuit in which a second fluid flows, in a direction which is generally in countercurrent in respect of the flowing direction of said first fluid. Both ends of the containers are tightly sealed by means of a suitable cover, of which the head cover comprises the inlet and outlet connectors of both fluids, and the bottom cover comprises the connectors by means of which the fluids pass from one tubular container to the other one.

ILLUSTRATION OF DRAWINGS

Other features and advantages of the invention will become apparent from reading the following description of a form of embodiment of the invention, given as a non-limiting example, with the help of the figures shown in the attached drawings, in which:

- figure 1 shows a schematical side section of a heat exchanger device according to the invention;

- figure 2 shows a schematical plan view of the device shown in fig. 1, and

- figure 3 shows a schematical side section of a combined water and air heating apparatus embodying the heat exchanger according to the invention.

In the figures, a quick-operating hat exchanger device according to the invention comprises a pair of tubular elongated containers 3, 7 having a generally cylindrical shape and which are disposed adjacent to each other.

Inside of each of said containers 3, 7 a pipeline is placed which, in the shown case, has a serpentine- like configuration, whereby the diameter of each coil is variable.

At the upper end of the pair of containers 3, 7 a first, generally metallic cover 1 is present; said cover 1 performs the triple functions of: tightly sealing said upper end; forming an element for connecting and reciprocally holding positioned both containers, and building up a connector element for the inlet and outlet conduits of the fluids into/from the heat exchanger .

Similarly, a second cover 2 is located at the lower end of the containers 3, 7; said second cover performs the triple functions of: tightly sealing said lower end; forming an element for connecting and reciprocally holding positioned both containers, and building up a connector element allowing the passage of the fluids from one container to the other one.

In the illustrated case, the cover 1, which is placed upon containers 3, 7 with the interposition of a suitable sealing gasket 8, comprises a series of peripheral holes which are suitable for receiving tie rods 6 connecting cover 1 to cover 2, said tie rods being placed outside of the pair of containers 3, 7.

The mentioned connection between the covers is carried out, in operation, by means of selflocking nuts 16; in this way, a rigid assembly is obtained, which comprises both containers 3, 7 and both covers 1, 2.

Furthermore, cover 1 comprises a first pair of holes that are suitable for sealingly house, with the interposition of suitable gaskets 9, the connecting elements 11, which are fastened by means ot nuts 10, for the respective pipes 4, 5 which are placed inside of the container s 3 , 7. Finally, cover 1 still comprises at least two inlet and outlet holes 12, 13 (figure 2 shows four holes) of the fluids into/from the containers 3, 7.

The bottom cover 2 has a structure which is identical to that of cover 1; however, in this case, holes 11 are suitable for housing the connectors foτ a pipeline 14 which connects pipes 4 and 5 to each other, while holes 12, 13 are suitable for housing the connectors for at least one pipeline 15 suitable for allowing the passage of a fluid from container 3 to container 7 or vice versa.

The exchanger device is completed by a suitable insulating material 17 which is placed roundabout the assembly containers/covers .

In operation, a primary fluid is inlet into pipeline 5 which is housed inside of container 7, it flows out of said container 7, it flows within pipeline 14, it is inlet into pipeline 4 which is housed within container 3 and it finally flows out from upper connector 11. Similarly, a secondary fluid is inlet, in counterc rient in respect of said primary fluid, into container 3 through inlet holes 12, it fills up said container, it flows out by means of pipeline 15 and it fills up container 7.

Finally, the secondary fluid flows out of the exchanger by means of holes 13.

In the case described above, a double thermal exchange takes place between the respective primary and secondary fluids, once in container 7 and another time in container 3, thereby achieving the scopes of the invention, since the thermal exchange is carried out in a very short time.

Furthermore, the energy which is necessary for driving - the respective primary and secondary fluids is extremely low, and the losses of pressure of the heat exchanger are extremely small, while keeping a large exchange surface.

In this context, it has been remarked that, considering a thermal power of e.g. 40.000 Kcal, the losses of pressure of a plate-like heat exchanger may be set to about 5 metres, while the losses of pressure of a heat exchanger according to the invention range between 0,3 and 0,5 metres.

The heat exchanger according to the invention may practically be used for any application requiring a thermal exchange to be carried out between two fluids of any kind, either gases or liquids.

Thus, it may be employed in heating or refrigerating circuits, thermal or frigorific machines.

According to another important feature of the invention, such a heat exchanger is modular.

It may actually be remarked that, while keeping the dimensions of the upper and lower covers unchanged, the thermal power of the heat exchanger may be modified by simply increasing or decreasing the length of containers 3, 7, what involves a remarkable saving during the production steps of the heat exchanger.

Figure 3 shows a particularly advantageous application of the invention, according to which the heat ecxhanger is used for building a combined water and air heating apparatus.

Apparatus 20 is housed within a receptacle 21 and comprises a pair of tubular elongated containers 3, 7 as previously described.

A first pipeline 4 is placed inside of container 3, while a second pipeline 5 is placed inside of container 7. According to the invention, the containers 3, 7 are provided with common upper and lower covers 1, 2.

Furthermore, pipelines 4, 5 are serially connected to each other by means of a pipeline 15 in the area of bottom cover 2. Moreover, bottom cover 2 includes the inlet and outlet connectors of respective pipelines 4, 5, while upper cover 1 includes inlet connectors 22 for the fluid which fills containers 3, 7.

According to this form of embodiment, upper cover 1 carries a series of connectors 23, 24, 25, 26 belonging to a fluid collector 27 which is generally placed on the top of upper cover 1.

The upper part of fluid collector 27 connected to a serpentine-like pipeline 28 belonging to an air/fluid heat exchanger 29,. on top of which a sucking fan 30 is placed.

Finally, a pair of electrical heating resistors 31, 32 are housed within respective containers 3, 7.

In operation, a first fluid (e.g. water) is inlet into apparatus 20 through connector 33 and it flows through pipeline 4, pipeline 15, pipeline 5 and connector 34.

A second fluid is inlet into container 3 through connectors 22, and it fills up said container 3, it flows through connectors 23, 24, it fills up fluid collector 27, it flows through pipeline 28, then through connectors 25, 26 and it fills up container 7. In the case where resistors 31, 32 are connected to an electrical power supply, said resistors warm up the second fluid, and the heat is transferred by conduction to the same fluid which is present in collector 27 and in pipeline 28.

At the same time, a heat exchange takes place between said first and second fluids, and the first fluid, which flows inside of pipelines 4 and 5 is heated. In the case where sucking fan 30 is on, warm air is sucked from heat exchanger 29 and distributed in the environment through suitable air outlets.

Apparatus 20 has a second operating way, in the case where there are no resistors, and where the first fluid is inlet inside of the apparatus in a hot state, as coming from a boiler.

In this case, the apparatus is provided with another pair of serpent ine-1 ike pipelines (not shown in the drawings) in which a third fluid flows, said first fluid heating up by thermal exchange the third fluid.

According to another form of embodiment, the resistors may also be replaced by burners.

The invention has been previously described with reference to an advantageous form of embodiment, according to which the heat exchanger is provided with a pair of containers, each of them housing a serpentine¬ like pipel ine.

However, the invention comprises several other forms of embodiment which fall within its scope. For instance, the invention comprises a form of embodiment according to which there is only one container inside of which the thermal exchange is carried out.

The shape and the dimensions of the container(s) may be modified relative to those which are illustrated in the figures, in accordance to the equivalents' principle.

The confi uration too, as well as the material constituting the pipeline which is placed inside of the container(s) may be widely modified.

In fact, the invention comprises forms of embodiment according to which the serpentine constituting said pipeline may for instance be finned, or have the shape of a square conduit, and be made of a metallic material like copper, or of a synthetic material such as metacrylate. The latter form of embodiment is particularly advantageous in the case where the heat exchanger would operate in a strongly acid environment, as in the case of electrical accumulator batteries.

It may finally be remarked that, due to the extremely simple structure of the heat exchanger, its surfaces may be treated by means of, e.g., enamel or resin; the invention comprises a form of embodiment according to which the surface of each container and cover which contacts the fluid is provided with a teflon (TM) layer.

In this way, the heat exchanger is made to be particularly resisting against the action of chemical agents, whereby its use as water heater inside of boilers for producing hot water for heating and/or sanitary use becomes particularly interesting.

In fact, the water heater's constituting elements (container, covers) are treated before the ultimate assembly, while state-of-the-art water heaters are internally glazed after the whole assembly having been previously welded.

The use as water heater of a heat exchanger according to the present invention allows such problems to be avoided, since there are no welding points and the elements constituting the water heater are treated before the ultimate assemblying operation.

Contrary to the known water heaters, such water heater is characterised by a very easy upkeep and by the possibility of quickly replacing any eventually damaged element s .

Claims

1. Quick operating heat exchanger device, comprising a vessel having at least one pair of inlet and outlet holes for a first fluid and one pair of inlet and outlet holes for a second fluid, said vessel housing a pipeline (4,5) in which said first fluid flows, characterised in that said vessel comprises at least one elongated container (3,7) provided with a pair of openings disposed in correspondence of two portions of said container, and a pair of covers (1,2) suitable for enabling a tightly sealed closure of said openings, said inlet and outlet holes for said first and second fluids being disposed on at least one of said covers (1,2).

2. Device according to claim 1, characterised in that said at least one container (3,7) has a tubular con iguration, whereby both its upper and lower ends are open.

3. Device according to claim 2, characterised in that it comprises a pair of adjacent containers (3,7), and in that each of said covers (1,2) is suitable for simultaneously closing the respective upper and lower ends of said containers (3,7).

4. Device according to claim 3, characterised in that said covers (1,2) are connected to each other by means of tie rods (6) which are disposed outside of said containers (3,7).

5. Device according to anyone of claims 3 and 4, characterised in that the upper cover (1) comprises the inlet and outlet holes for said first and second fluids.

6. Device accoding to anyone of claims 3 to 5, characterised in that the lower cover comprises connector elements for connecting pipelines suitable for allowing said first and second fluids to pass from one container to the other one.

7. Device according to anyone of the preceding claims, characterised in that the pipeline (4,5) housed within said at least one container (3,7) has a serpent ine-1 ike configuration.

8. Device according to anyone of the preceding claims, characterised in that it comprises an insulating material disposed outside of said device.

9. Device according to anyone of the preceding claims, characterised in that the surfaces of said at least one container (3,7) and of said covers (1,2) which are in contact with one of said fluids are suitably treated in order to resist to the action of chemical agents.

10. Device according to claim 9, characterised in that said surfaces are provided, before assemblying said device, with a teflon (TM) layer.

11. Water heater for boilers suitable for producing hot water for sanitary and/or heating use, characterised in that it is constituted by a heat exchanger device according to anyone of the preceding claims.

12. Combined air and water heater apparatus (20), comprising a device according to anyone of the preceding claims, wherein said upper cover (1) is connected to a fluid collector (27) and said fluid collector (27) is connected to a air/fluid heat exchanger (29), a sucking fan (30) cooperating with said air/fluid heat exchanger for distributing heated air to the environment.

13. Apparatus (20) according to claim 12, wherein the fluid contained in said containers (3, 7) is warmed up by means of electrical resistors (31, 32) and/or burners and/or by the the fluid flowing in the pipelines (4, 5) housed within said containers (3, 7)