Buffer tank and heat exchanger

Abstract

The invention relates to a buffer tank and a heat exchanger, in particular a buffer tank and a heat exchanger for household and industrial water-heating systems, comprising a container base (16) for receiving a container (1), consisting of a thermoplastic liner (2) and a fibre-reinforced outer covering (3) wound around the liner (2), wherein the liner (2) consists of a shell (4) and end faces (6, 7) with moulded-on semicircular end plates (19, 20). The shell (4) of the liner (2) contains pipe-attachment points (5) with plastic load-bearing internal threads (12) and connectors (10) integrally formed by plastics moulding processes, in particular rotary sintering or casting, and an opening (9) which is located in the end plate (19) of the end face (6) of the liner (2), can be sealed pressure-tightly by a cover (8) and serves as an inspection opening or as an opening for the installation of a heat source (25), in particular a heating register (24), wherein a metal ring (13) with rivet nuts (14) and with a sealing seat (15) is integrally formed around the opening (9) in the end plate (19) of the liner (2) by plastics moulding processes, in particular rotary sintering or casting. The pipe-attachment points (5) are formed in such a way that they can receive heat sources (25), in particular heating cartridges.

Description

[0001] Buffer tank and heat exchanger

[0002] The invention relates to a buffer tank and a heat exchanger, in particular a buffer tank and heat exchanger for domestic and industrial hot water treatment systems.

[0003] The buffer tanks or containers known from the state of the art in domestic water heating systems are predominantly made of stainless steel or copper and are usually surrounded by a thermal insulation layer. Tanks made of enameled or galvanized sheet steel were also offered. Such containers are subject to severe corrosion. Depending on the aggressiveness of the water, the service life of even copper containers can be very short. To slow the corrosion and deposition process, sacrificial anodes are used as cathodic protection.

[0004] Also known from the prior art are liquid containers which are manufactured from thermoplastic material using the blow molding or rotational melt molding process, but which are not suitable for these purposes because they cannot withstand the required water pressure, especially when heated.

[0005] Plastic containers are also known in which an outer shell made of glass-fiber-reinforced synthetic resin is wrapped over an inner wall made of thermoplastic. This initially creates a generally circular hollow body with a more or less large opening at each end. The edges of the inner wall, thickened at these openings, are designed as flange rings, each of which has threaded holes at regular intervals on its end face to allow the opening to be closed with a screwed-on lid. These lids are then also used for attaching pipe connections and fittings.

[0006] High-pressure vessels for gaseous media are also known from the prior art. These vessels consist of a thermoplastic liner and a glass-fiber-reinforced casing. Metal connectors, in particular connectors for valves, are incorporated into the liner and form a material bond with the thermoplastic of the liner. DE 24 25 424 A1 discloses a plastic hot water tank in which an outer wall made of glass-fiber-reinforced thermosetting resin is wrapped over an inner wall made of thermoplastic.The inner wall is closed on one end, known as the container base, and open on the other end and provided with a short, cylindrical extension, with a flange ring fitting over the cylindrical extension on the open side, with threaded holes arranged at regular intervals in the end face and a collar-like edge resting on the outer surface of the container's inner wall, the latter being covered by the outer wall of the container.

[0007] The flange ring has threaded holes arranged at regular intervals on its end face, which serve to attach a cover with screws. The cover is provided with connections for pipes and fittings. DE 43 16 219 B4 discloses a water heater made of a temperature-resistant plastic material. The water tank is composed of two half-shells, with the connecting pieces for the cold water inlet and the hot water outlet formed on one end face. An opening is provided on the other end face of the water tank, the projecting edge of which is equipped with a thread for screwing in a cover.

[0008] The invention according to WO 2015 014 615 A1 relates to a water heater having a base tank for holding water. The base tank has at least one inlet for water to be heated and at least one outlet for heated water. The water heater further comprises a housing made at least partially from a heat-insulating polyurethane material and at least partially surrounding the base tank. The outlet extends through the housing and has at least one section that extends vertically downwards within the housing substantially from the top of the base tank. The inlet is designed as a straight pipe and is connected or attached to the base tank near the bottom and extends through the side wall of the base into the interior of the base tank.

[0009] EP 0 565 782 A1 describes a storage heater or tank for domestic boilers, consisting of a substantially elliptical, cylindrical or similar shell with partially spherical ends provided with a bottom flange and an inlet flange for access and fixing, such a plastic shell intended to ensure a watertight seal and lined with one or more layers of high-strength fibers arranged in a circumferential direction with different inclinations to the generatrix or to the axis of the shell, such lining layers being able to withstand the axial and radial stresses generated by the contents and by the pressure inside the shell, the end flanges also being formed by a part of the lining of fibers having a lower inclination to the axis.are integrated into the casing and bonded with synthetic adhesive resin to reduce the tensile and shear stresses to which said fibers are subjected. The casing is described as a blow-molded casing made of plastic material, e.g., high-density polyethylene or the like. The invention EP 2 592 361 A1 relates to a plastic storage container for a fluid medium, in particular for heated heating water or heated drinking water, wherein at least one mounting opening of the storage container is closed with a lid for a head-end mounting opening of the storage container to be closed and / or with a base for a foot-end mounting opening of the storage container to be closed, and the storage container is at least partially reinforced or wrapped on the outside with a fiber composite material.

[0010] The walls of the storage container, and in particular the walls of the lid and base, are made entirely or essentially entirely of plastic. The plastic is advantageously a thermoplastic polymer. It is recommended that the thermoplastic polymer be a polyolefin, and advantageously a polyethylene and / or polypropylene.

[0011] The storage container has a barrier layer made of metal, plastic, or a lacquer, which prevents corrosive gases from diffusing into the interior of the storage container and which is arranged between the storage container and the fiber composite material. The lid and the base each have a connecting element, to which the extraction device and the feed device are preferably connected. The invention according to DE 10 2020 001 135 B3 relates to a pressure vessel and a method for producing a pressure vessel made of plastic for a pressurized, flowable or gaseous medium for pressures up to 700 bar and above.The pressure vessel consists of an inner container made of plastic with connecting pieces arranged on the end faces for accommodating valves and of an outer shell made of a fiber-reinforced reinforcement, wherein the connecting pieces are molded, in particular rotated, into the wall of the end faces of the inner container and are surrounded by the fiber-reinforced reinforcement of the outer shell.

[0012] The connecting pieces consist of a hub, a cylindrical center piece and a flange, whereby the hub is provided with a bore carrying an internal thread, an external thread arranged at the lower end of the hub reaching into the interior of the inner container, the center piece with anti-twist devices distributed around the circumference and threaded bores arranged on the front side of the cylindrical center piece and the flange is provided with undercuts and anti-twist devices.

[0013] WO 2014 118 338 A1 presents a heating system comprising one or more heat sources, a tank, and one or more heat users. The tank contains a heat transfer medium and an energy storage medium that defines a thermal energy store. The energy storage medium comprises a phase-change material, and the phase-change material is packaged in bags, and the bags are arranged in the tank such that heat transfer occurs. The medium can flow at least partially around the bags to charge and discharge it. The tank is provided with several connection pieces attached to the shell of the tank and to the top of the tank for the supply and discharge of media for various heat sources and heat users. The tank and the connection pieces, as well as their attachment to the tank, are not disclosed.

[0014] CN 10 295 934 A1 describes a pressure-resistant and heat-resistant tank made of plastic, which has a container wall surface section consisting of a multi-layer structure with an inner layer made of polyphenylene ether resin, an outer layer made of polyamide resin and an intermediate layer made of a polyphenylene ether resin composition arranged between the inner layer and the outer layer and containing polyphenylene ether resin and polyamide resin.

[0015] US 2015 345 827 A1 describes a buffer water storage tank that integrates hot water and heating and has a tank body covered with a thermal insulation layer, such as thermal insulation cotton. This buffer water storage tank is used to connect hot water connections from heat sources to heat sinks. WO 2022 229 477 A1 describes a pressurized plastic hot water storage tank for hot water preparation or heating, which is made of plastic material, in particular PERT material. The storage tank consists of a cylindrical body consisting of a cylinder, tube, or rigid SDR tube made of PERT material and two curved ends, preferably in the form of spherical caps, which are attached to the respective ends of the tube by welding with a molecular bonding system or butt welding.

[0016] The cold water inlet connections, water outlet connections and connections for the heat sources are connected to the plastic storage tank by welding.

[0017] All buffer tanks or containers known from the state of the art are made of stainless steel or copper, encased in a thermal insulation layer of foam or thermal insulation cotton. The cold water inlet connections, water outlet connections, and heat source connections are welded to the buffer tank. Enameled or galvanized sheet steel versions are also available.

[0018] Depending on the aggressiveness of the water, the lifespan of even copper tanks may be very short. To slow the corrosion and scaling process, sacrificial anodes are used as cathodic protection.

[0019] The use of sacrificial anodes and the welding of the connections to the buffer tank result in increased manufacturing costs and there is a risk that leaks may occur through the welded connection in the event of load changes and pressure changes.

[0020] The object of the invention is to create a buffer tank and heat exchanger, in particular a hot water buffer tank and heat exchanger, for domestic and industrial hot water treatment systems and for domestic and industrial central heating systems, which eliminates the disadvantages of the prior art, consists of a plastic tank and thus reduces the risk of corrosion and has no welded joints that can lead to leaks due to load changes. The object of the invention is achieved by a buffer tank and heat exchanger, in particular a hot water buffer tank and heat exchanger for domestic and industrial hot water treatment systems, with a tank base 16 for receiving a tank 1, wherein the tank 1 consists of a liner 2 made of thermoplastic material and a fiber-reinforced outer shell 3 wound around the liner 2, and the liner 2 consists of a jacket 4 and end faces 6, 7 with molded-on semicircular bottoms 19, 20.

[0021] In the casing 4 of the liner 2, pipe receptacles 5 with a supporting plastic internal thread 12 and molded-in connecting pieces 10 are arranged, and in the base 19 of the end face 6 of the liner 2, an opening 9 which can be closed pressure-tight with a cover 8 is arranged as an inspection opening or as an opening for the installation of a heating register 24, wherein a metal ring 13 with rivet nuts 14 and with a sealing seat 15 is arranged around the opening 9 in the base 19 of the liner 2.

[0022] The connecting pieces 10 consist of a head 17 and a cylindrical shaft 18 and are provided with an internal thread 21 which corresponds to the plastic internal thread 12 of the pipe holder 5.

[0023] The connecting pieces 10 with their head 17 and with their shaft 18 and the metal ring 13 arranged in the base 19 of the liner 2 with rivet nuts 14 and the sealing seat 15 are completely molded into the liner 2 during the plastic forming process. The connecting pieces 10 are incorporated into the pipe receptacles 5 of the shell 4 of the liner 2 with threaded bolts 11 that can be subsequently removed from the connecting pieces 10 to form a supporting plastic internal thread 12 molded into the pipe receptacles 5 for the pipe connections of heat sources 25 and heat users 26 during the plastic forming process, wherein after completion of the plastic forming process of the liner 2, the threaded bolt 11 is removed from the pipe receptacles 5 and the connecting pieces 10 so that the supporting plastic internal thread 12 for receiving pipe connections has been formed in the pipe receptacles 5.

[0024] The liner 2 with the pipe receptacles 5 and the opening 9 is then wrapped with the fiber-reinforced outer shell 3, wherein cutouts 22 for the pipe receptacles 5 and a cutout 23 for the opening 9 are formed in the outer shell 3. The internal thread 21 of the connecting pieces 10 serves as a guide for mounting the pipes in the plastic internal thread 12 during the installation of pipes in the pipe receptacles 5. This prevents the pipes from tilting during installation of the pipes in the pipe receptacles and thus prevents the load-bearing plastic internal thread 12 from being destroyed, since the load-bearing plastic internal thread 12 not only supports the pipe connections but also has a sealing function with respect to the pipe connections.

[0025] In one embodiment of the invention, a heating register 24 can be arranged in the container 1 as a heat source 25 in the buffer tank and heat exchanger, which is fastened to the metal ring 13 with its rivet nuts 14.

[0026] The heating register 24 can be connected to a heat pump, a solar collector or a burner for gaseous or liquid media to generate the heat

[0027] In a further embodiment of the invention, the pipe receptacles 5 with their portable plastic internal thread 12 can be designed to accommodate heating cartridges as heat sources 25.

[0028] The heating cartridges can be connected to a photovoltaic system. Using the threaded bolt 11, the supporting plastic internal thread of the pipe holder can be variably designed in terms of length, thread type, and thread size, and adapted according to customer requirements. Different heat sources and heat users can be connected to the buffer tank and heat exchanger simultaneously.

[0029] The connecting pieces 10 and the metal ring 13 with the rivet nuts 14 can be rotated or cast into the liner 2 made of thermoplastic material.

[0030] The connecting pieces 10 and the metal ring 13 are made of metal, in particular of structural steel, stainless steels, aluminum alloys, brass or other copper alloys and are subjected to a surface treatment by means of a heat treatment before being processed as an insert in the plastic forming process.

[0031] After being wrapped with the fiber-reinforced outer shell 3, the container 1 can additionally be provided with a thermal insulation layer.

[0032] The invention is explained in more detail using an example, wherein Fig. 1 shows the buffer tank and heat exchanger with tank base 16, Figs. 2 and 3 are a schematic sectional view of the tank 1, Fig. 4 is a sectional view of the detail A with the pipe receptacle 5 of the tank 1, Fig. 5 is a sectional view of the detail A of the pipe receptacle 5 of the tank 1, Fig. 6 is a view of the connecting piece 10 with threaded bolt 11, Fig. 7 is a view of the connecting piece 10, Fig. 8 is a sectional view of the detail B with the lid 8 and opening 9 of the tank 1, and Fig. 9 is a schematic example of the application of the buffer tank and heat exchanger, wherein

[0033] 1 container

[0034] 2 liners

[0035] 3 fiber-reinforced outer shell

[0036] 4 coats

[0037] 5 Pipe holder

[0038] 6 Front side with floor 19

[0039] 7 Front side with floor 20

[0040] 8 lids

[0041] 9 Opening

[0042] 10 connector

[0043] 11 threaded bolts

[0044] 12 Plastic internal thread of the pipe holder 5

[0045] 13 metal ring

[0046] 14 rivet nut

[0047] 15 Sealing seat

[0048] 16 Container base

[0049] 17 Head of the connector 10

[0050] 18 Shaft of the connecting piece 10

[0051] 19 Bottom of the front side 6

[0052] 20 Bottom of the front side 7

[0053] 21 Internal thread of the connectors 10

[0054] 22 Clearance for pipe receptacles 5 in the fiber-reinforced outer shell 3

[0055] 23 Clearance for opening 9 in the fiber-reinforced outer shell 3

[0056] 24 heating registers

[0057] 25 Heat source

[0058] 26 heat users. Examples

[0059] 1. The connecting pieces 10 are manufactured from stainless steel by machining processes such as turning, milling, drilling and form erosion, whereby the connecting pieces 10 consist of the head 17 and the cylindrical shaft 18 and are provided with an internal thread 21 which corresponds to the supporting plastic internal thread 12 of the pipe holder 5.

[0060] The connecting pieces 10 are then subjected to a surface treatment with an adhesive and a heat treatment. The connecting pieces 10, with the threaded bolts 11 screwed into the connecting pieces 10, are then inserted and secured into a mold for a rotational sintering process in such a way that the connecting pieces 10 are rotated into the PE plastic material in the shell of the liner 2 during the production of the liner 2 by rotational sintering. The connecting pieces 10, including their head 17 and their shaft 18, and the metal ring 13 arranged in the base 19 of the liner 2, with the rivet nuts 14 and the sealing seat 15, are molded into the liner 2 using the plastic forming process.

[0061] After completion of the plastic forming process of the liner 2, the threaded bolt 11 is removed from the pipe receptacles 5 and the connecting pieces 10, so that the supporting plastic internal thread 12 for receiving pipe connections has been formed in the pipe receptacles 5.

[0062] The liner 2 with the pipe receptacles 5 and the connecting pieces 10 arranged in the pipe receptacles 5 and the opening 9 with the metal ring 13 molded into the liner 2 is then wrapped with the fiber-reinforced outer shell 3, wherein openings 22 for access to the pipe receptacles 5 and a opening 23 for the opening 9 and the rotated-in metal ring 13 with rivet nut 14 and sealing seat 15 are incorporated into the outer shell 3.

[0063] The threaded bolts 11, which extend from the connecting pieces 10 into the interior of the liner 2 formed by the plastic forming process, in this case rotational sintering, are used to form the supporting plastic internal threads 12 onto the connecting pieces 10 during the plastic forming process, in this case rotational sintering. The supporting plastic internal threads 12 of the pipe receptacles 5 extend into the interior of the liner 2. By varying the length of the threaded bolt 11, the length, type, and size of the thread of the supporting plastic internal thread 12 can also be varied as required.

[0064] 2. The container 1 according to example 1 is, as shown in Fig. 9, equipped with a heating register 24 as heat source 25 and with a heating cartridge accommodated in a pipe holder 5 as heat source 25 as well as with heat users 26 shown as radiators and shower heads, wherein the heating register 24 is connected to a heat pump or a solar collector and the heating cartridge is connected to a photovoltaic system via a converter.

[0065] The inventive buffer tank and heat exchanger with a liner 2 made of thermoplastic material and a fiber-reinforced outer shell 3 wound around the liner 2 and with pipe receptacles 5 molded into the liner 2 of the plastic liner and a metal ring 13 molded into the bottom of an end face of the plastic liner for connecting the heat sources and users creates a buffer tank and heat exchanger that is significantly less expensive than the buffer tanks known from the prior art and that has a high durability due to less corrosion and deposits.

Claims

AMENDED CLAIMS received by the International Bureau on 18 April 2024 (18.04.2024) 1. Buffer tank and heat exchanger, in particular a hot water buffer tank and a hot water heat exchanger for domestic and industrial hot water treatment systems, comprising a tank base (16) for receiving a tank (1), consisting of a liner (2) as an inner tank made of thermoplastic material and a fiber-reinforced outer shell (3) wound around the liner (2), wherein the liner (2) consists of a casing (4) and end faces (6, 7) with integrally formed convex-shaped bases (19, 20), and pipe receptacles (5) with plastic internal threads (12) are arranged in the casing (4) of the liner (2), characterized in that the pipe receptacles (5) extending into the interior of the liner (2) consist of connecting pieces (10) molded into the pipe receptacles (5) and of supporting threaded pieces (11) made of thermoplastic material and having a supporting internal thread (12) extending into the interior of the pressure vessel.wherein the threaded pieces (11) are formed on the connecting pieces (10) and are provided with an internal thread (12) corresponding to the internal thread (21) of the connecting pieces (10), and an opening (9) is arranged in the bottom (19) of the end face (6) of the liner (2), and a molded-in metal ring (13) with rivet nuts (14) and a sealing seat (15) are arranged around the opening (9) in the bottom (19) of the liner (2).

2. Buffer tank and heat exchanger according to claim 1, characterized in that in the pipe receptacles (5) of the jacket (4) of the liner (2) the connecting pieces (10) are arranged with a threaded bolt (27) which can be subsequently removed from the connecting pieces (10) for forming a supporting plastic internal thread (12) formed in the pipe receptacles (5) for the pipe connections of heat sources (25) and heat users (26) during the plastic forming process. AMENDED SHEET (ARTICLE 19) 3. Buffer tank and heat exchanger according to claim 1, characterized in that the opening (9) is designed as an opening (9) which can be closed pressure-tight with a cover (8).

4. Buffer tank and heat exchanger according to claim 1 - 2, characterized in that a heating register (24) is arranged in the container (1) as a heat source (25), wherein the heating register (24) is fastened to the metal ring (13) with rivet nuts (14).

5. Buffer tank and heat exchanger (1) according to claim 1 - 2, characterized in that the pipe receptacles (5) with the supporting plastic internal thread (12) are designed to accommodate heating cartridges as a heat source (25).

6. Buffer tank and heat exchanger (1) according to claims 1 - 2 and 4, characterized in that the connecting pieces (10) consist of a head (17) and a cylindrical shaft (18) and are provided with an internal thread (21).

7. Buffer tank and heat exchanger (1) according to claims 1 - 6, characterized in that the connecting pieces (10) with their head (17) and with their shaft (20) and the metal ring (13) arranged in the bottom (21) of the liner (2) with rivet nuts (14) and the sealing seat (15) are molded into the liner (2) in a plastic forming process.

8. Buffer tank and heat exchanger (1) according to claim 7, characterized in that the connecting pieces (10) and the metal ring (13) with the rivet nuts (14) are rotated or cast into the liner (2) made of thermoplastic material.

9. Buffer tank and heat exchanger (1) according to claims 1 - 8, characterized in that the liner (2) is wrapped with the fiber-reinforced outer shell (3), wherein cutouts (22) for access to the pipe receptacles (5) and a cutout (23) for the cover (7) are formed in the outer shell (3).

10. Buffer tank and heat exchanger according to claims 1 - 9, characterized in that the connecting pieces (10) and the metal ring (13) are made of metal, in particular of structural steel, stainless steel, aluminum alloys, brass or other copper alloys, and before processing as AMENDED SHEET (ARTICLE 19) Insert in the plastic forming process is subjected to a surface treatment by means of heat treatment.

11. Buffer tank and heat exchanger according to claims 1 - 10, characterized in that the container (1) is provided with a thermal insulation layer after being wrapped with the fiber-reinforced outer shell (3). AMENDED SHEET (ARTICLE 19)

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