EP-4737817-A1 - CONNECTION DEVICE FOR A GEOTHERMAL PROBE AND METHOD FOR FORMING A CONNECTION DEVICE

EP4737817A1EP 4737817 A1EP4737817 A1EP 4737817A1EP-4737817-A1

Abstract

The disclosure provides a connection device for supply and return lines of heat transfer fluid of a geothermal probe. The connection device includes an inlet connection designed to connect to a supply line of heat transfer fluid, and an outlet connection intended for a return line. It features a first tubular portion connected to the inlet connection and a second tubular portion connected to the outlet connection. Additionally, a third tubular portion is connected to either the first or second tubular portion. The first tubular portion includes a tubular bending section that connects to the second tubular portion, forming a tubular U-shape, allowing fluid to flow from the inlet through the first and second tubular portions to the outlet. The first tubular portion extends longitudinally beyond a central transversal plane located centrally between the inlet connection and the outlet connection. The third tubular portion acts as a tubular appendix to the U-shape. The connection device is formed as a single piece. The disclosure also provides a method for forming the aforementioned connection device in a single step, preferably through injection moulding using a mould with a collapsible core.

Inventors

DE BOER, Pascal
HESSELING, Thomas Jan
EEK, JOHANNES EVERARDUS

Assignees

Dyka B.V.

Dates

Publication Date: 20260506
Application Date: 20251008

Claims (15)

Connection device (20) for connecting supply and return lines of heat transfer fluid of a geothermal probe, the connection device comprising: - an inlet connection (21) intended to be connected to a supply line of heat transfer fluid; - a first tubular portion (22) connected to the inlet connection (21); - an outlet connection (26) intended to be connected to a return line of the heat transfer fluid; - a second tubular portion (25) connected to the outlet connection; - a central transversal plane (P) located centrally between the inlet connection (21) and the outlet connection (26) wherein the first tubular portion comprises a tubular bending section, wherein the tubular bending section is connected to the second tubular portion (25) so that the first tubular portion (22) and the second tubular portion (25) together form a tubular U-shape and fluid can flow from the inlet connection (21) through the first tubular portion (22) to the second tubular portion (25) and through the outlet connection (26); wherein the connection device further comprises a single third tubular portion (24), connected to the first tubular portion (22) and/or the second tubular portion (25), wherein the third tubular portion (24) forms a single tubular appendix to the tubular U-shape (23), placed asymmetrically with respect to the central transversal plane (P); and wherein the first tubular portion (22) extends longitudinally from the inlet connection (21) beyond the central transversal plane (P) up to the third tubular portion (24).
Connection device (20) according to claim 1, wherein: - the single third tubular portion (24), forms a single tubular appendix to the tubular U-shape (23), placed only at a single side of the central transversal plane (P); or - the single third tubular portion (24), forms a single tubular appendix to the tubular U-shape (23), placed only at a the same side of the central transversal plane (P) as the outlet connection (26).
Connection device (20) according to claim 1 or 2, wherein the first tubular portion (22) is formed using injection moulding, wherein the injection moulding comprises using a mould with a core (57).
Connection device (20) according to claim 3, wherein the core (57) is a collapsible core (57) comprising a plurality of segments (52-56), wherein the collapsable core (57) is configured to: - be in a collapsed state inside the mould during at least a part of the injection moulding, in which the plurality of segments (52-56) are tightly connected to each other and the collapsible core (57) forms a robust form for the single moulding; and - be in an extended state for removal from the mould, in which the plurality of segments (52-56) are flexibly connected to each other so that the plurality of segments (52-56) are movable with respect to each other.
Connection device (20) according to any one of the preceding claims, wherein the third tubular portion (24) is aligned with the first tubular portion (22) or the second tubular portion (25), preferably with the second tubular portion (25).
Connection device (20) according to any one of the previous claims, further comprising a tab portion (30) connected to one or more of the first tubular portion (22), the second tubular portion (25), and the third tubular portion (24), wherein the tab portion (30) is tapering from a location proximal to the U-shape to a location distal from the U-shape, preferably wherein the tab portion (30) comprises at least one reinforcing rib (31, 32, 33), more preferably two reinforcing ribs, most preferably 3 reinforcing ribs.
Connection device (20) according to claim 6, wherein the tab portion (30) comprises at least one reinforced through hole (34, 35) configured for being connected to a pulling weight.
Connection device (20) according to any one of the preceding claims, wherein the connection device comprises, preferably consists of, thermoplastic material, such as polyethylene, PE.
Connection device (20) according to any one of the preceding claims, wherein the connection device is asymmetrical and includes visible indications on or near the inlet connection (21) and/or outlet connection (26) indicating an intended flow direction of heat transfer fluid.
Connection device (20) according to any one of the preceding claims, wherein the third tubular portion (24) comprises at least one traverse rib (29) spanning the tubular portion.
Connection device (20) according to any one of the preceding claims, wherein the connection device is a single piece, preferably wherein the connection device is moulded as a mono block.
Geothermal probe (100) comprising a supply line of heat transfer fluid (104) and a return line of heat transfer fluid (105), characterized in that it further comprises a connection device (20) according to any one of claims 1-11, the inlet connection (21) being connected to the supply line of heat transfer fluid and the outlet connection (26) being connected to the return line of heat transfer fluid.
Method for forming a connection device (20) according to any of claims 1-11, the method comprising: - providing a mould with a collapsible core (57) for the tubular bending section, wherein the collapsible core (57) comprises a plurality of segments (52-56); - injecting moulding material into the mould; - forming the connection device (20) in a single moulding step, - removing the formed connection device (20) from the mould, wherein the collapsible core (57) is in a collapsed state inside the mould during the single moulding step, in which the plurality of segments (52-56) are tightly connected to each other; wherein the collapsible core (57) is in an extended state during removal from the mould of the formed connection device (20), in which the plurality of segments (52-56) are flexibly connected to each other so that plurality of segments (52-56) are movable with respect to each other.
Method for forming a connection device (20) according to claims 12 or 13, comprising injection moulding using a thermoplastic, preferably polyethylene.
Method for forming a connection device (20) according to any one of claims 12-14, wherein forming the connection device (20) is done in a single operation without the need for subsequent welding connections.

Description

Field of the invention The present disclosure relates to a connection device for supply and return lines of heat transfer fluid of a geothermal probe, and a geothermal probe comprising such a connection device. The disclosure also relates to a method for forming such a connection device. Background of the invention A geothermal probe comprises a supply line of heat transfer fluid and a return line of heat transfer fluid arranged vertically in a borehole of 30 - 300 meters or more. The supply and return lines of heat transfer fluid are connected at the bottom by a connection device, generally in a Y-shape, allowing a flow of heat transfer fluid from the supply line to the return line. At the top, the lines are connected to pipes arranged to connect the lines to a heat pump installed in a technical room of a building. The operating principle of a geothermal loop, of which the geothermal probe is a part, consists of capturing calories stored in the ground through the supply and return lines of heat transfer fluid which constitute vertical heat exchangers, and transferring them to the heat pump which extracts these calories from the heat transfer fluid and returns them to a heating circuit of the building. In the context of this application, the geothermal loop is the entirety of the system, including pumps, tubes and connection device. The geothermal probe is the part of the geothermal loop that is, in installation, in a bore hole in the ground, comprising supply and return tubes or lines and a connection device connecting the tubes or lines. The connection device is used to change the flow 180 degrees upwards again through the return line, with pressure loss as low as possible. The supply and return lines of heat transfer fluid, the heat pump and the pipes connecting the latter form a closed circuit, the geothermal loop, in which the heat transfer fluid circulates. Figure 1 is a perspective view of a prior art Y-shaped connection device. Figure 2 is a perspective view in longitudinal section of the prior art connection device of figure 1. Figures 1 and 2 show a connection device (2) for supply and return lines of heat transfer fluid of a geothermal probe. The connection device (2) comprises a substantially rectilinear first tubular portion (3) and a substantially rectilinear second tubular portion (4), the first and second tubular portions being inclined relative to each other and extending in the same plane. The first tubular portion (3) is longer than the second tubular portion (4) and extends below the point where the two portions meet, so that the connection device (2) thus has substantially the shape of the letter Y. The first tubular portion (3) of figure 2 has a first end (5) intended to be connected to a return line of heat transfer fluid and a closed second end (6). The second tubular portion (4) has a first end (7) intended to be connected to a supply line of heat transfer fluid and a closed second end (8). The second tubular portion (4) includes an opening (9) provided in its side wall at its second end (8), said opening (9) opening into the first tubular portion (3) upstream of the closed second end (6) of the latter. The connection device (2) of figures 1 and 2 further comprises a tab (11) arranged at the closed end (6) of the first tubular portion (3), the tab (11) extending in the extension of the first and second lines (3, 4). The tab (11) has two through openings (12) arranged to allow the attachment of a weight and/or a protection device to pull the connection device into the bore hole. Such a prior art device can be formed as a single piece of plastic such as polyethylene (PE) using conventional injection moulding. For example, such a device can be made as a single piece in one step through injection moulding where the core is pushed in and then retracted. However, due to the somewhat abrupt way in which the first and second rectilinear tubular portions (3) and (4) are connected through opening (9) as shown in figure 2, the flow through the connection device (2) is not optimal. This results in higher demands for the pump that pumps the heat transfer fluid, leading to increased costs and higher chances of malfunction. As a result, there is a need for a connection device with improved flow characteristics. Summary of the invention The disclosure provides a connection device for connecting supply and return lines of heat transfer fluid of a geothermal probe, the connection device comprising an inlet connection intended to be connected to a supply line of heat transfer fluid; a first tubular portion connected to the inlet connection; an outlet connection intended to be connected to a return line of the heat transfer fluid; a second tubular portion connected to the outlet connection; a central transversal plane located centrally between the inlet connection and the outlet connection; a third tubular portion, connected to the first tubular portion and/or the second tubular portion; wherein the fi