Defrosting process for a fluid distribution system

Abstract

The invention relates to a method for defrosting a fluid pipeline equipped with fins arranged projecting from its outer periphery, which has surface frost. The method comprises a step of positioning a defrosting device comprising at least one defrosting blade cooperating with the fins, and a step of moving the defrosting device along the pipeline so as to remove at least a portion of the frost by mechanical action of the defrosting blade over at least a portion of the surface. Abstract figure: Fig. 1

Description

Title of the invention: Defrosting method for a fluid distribution system

[0001] The present invention relates to a method for defrosting a cryogenic fluid distribution system, and more particularly to defrosting an atmospheric heat exchanger or heater in such a fluid distribution system. The invention further relates to a defrosting device.

[0002] In order to be used in gaseous form, the fluid must be heated. This is done using a heat exchanger, for example, an atmospheric heater / exchanger. This type of heater draws the energy necessary for vaporizing the cryogenic liquid from the ambient atmosphere by means of an external exchange surface. During this heat exchange, frost can form on the coldest areas of the exchanger, particularly those located upstream of the cryogenic fluid flow. Frost significantly impairs the performance of the exchanger, even preventing the fluid from heating. Consequently, the fluid is no longer sufficiently heated, a liquid phase appears, and liquid then flows into the pipes.

[0003] Some systems are equipped with a first heat exchanger, a second heat exchanger, and an automatic switching system that allows the system to switch from one heat exchanger to the other when fluid is present. This switching allows the first heat exchanger to defrost, if the ambient temperature permits, while the system uses the second heat exchanger. However, the switchover must be performed at the right time, otherwise frost may form on both heat exchangers.

[0004] Some installations are equipped with defrosting devices, such as a scraper. EP 4083556 Al presents such a system with a scraper. The disclosed scraper has the disadvantage of not being suitable for more complex pipe geometries. Furthermore, the disclosed scraper tends to become blocked by frost against the pipe, rendering it inoperable.

[0005] The present invention aims to effectively overcome these drawbacks by proposing a method for defrosting a fluid pipeline equipped with fins arranged projecting on an external periphery of the pipeline, and comprising frost on the surface of the pipeline, the method comprising:

[0006] - a positioning step of a de-icing device comprising at least one defrosting blade cooperating with the fins, and

[0007] - a step of moving the de-icing device along the pipeline in order to remove at least some of the frost by mechanical action of the at least a defrosting blade of the defrosting device on at least part of the surface of the fins.

[0008] Depending on the case, the movement of the defrosting device is carried out in such a way as to eliminate at least part of the frost on the periphery of the pipe.

[0009] The invention further relates to a pipe de-icing device comprising:

[0010] - at least one defrosting blade configured to cover at least part of the surface of the pipe, and including a draft angle on at least one end,

[0011] - a motorized actuator for moving at least one defrosting blade.

[0012] Depending on the case, the invention may include one or more of the following features stated below.

[0013] The motorized actuator comprises:

[0014] - at least one threaded shaft carrying at least one defrosting blade,

[0015] - an oblique element to said threaded axis, and

[0016] - a motor enabling the rotation of the oblique element.

[0017] The defrosting device comprises at least four defrosting blades fixed together in pairs.

[0018] The invention further relates to a cryogenic fluid distribution installation comprising at least one atmospheric fluid heater equipped with at least one pipe comprising at least several fins, and the installation includes at least one de-icing device according to the invention arranged around at least one pipe.

[0019] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only to illustrate, but in no way limit, the invention.

[0020] [Fig-1] is a schematic representation of part of a defrosting device in an embodiment according to the invention;

[0021] [Fig.2] is a schematic and cross-sectional representation of a defrosting device positioned around a pipeline according to a specific embodiment; and

[0022] [Fig.3] is a schematic representation of a fluid distribution installation.

[0023] With reference to [Fig. 2], the de-icing device 1 according to a first embodiment of the invention is shown installed around a pipe 6. The pipe 6 is at least partially covered with frost. The pipe 6 to be de-iced is provided with fins 2. These fins 2 are arranged projecting from the outer periphery of the pipe 6.

[0024] The defrosting device 1 comprises at least one defrosting blade 4 shown in [Fig. 1]. This defrosting blade 4 is configured to cover at least a part of the pipe 6 equipped with fins 2. The de-icing blade 4 includes at least one protrusion. In one embodiment, the de-icing blade 4 includes at least three protrusions. These protrusions at least partially cover the external surface of the pipe 6 equipped with fins 2. These protrusions specifically cover the fins 2. Thus, thanks to its shape including protrusions, the de-icing blade 4 adapts to the surface of the pipe 6 equipped with fins 2.

[0025] The defrosting blade 4 also includes a so-called chamfer angle on one of its ends. This particular angle allows the blade 4 to remove frost more easily when the defrosting blade 4 is moved along the pipe. The defrosting blade 4 may, in one embodiment, include a recessed portion. This recessed portion prevents frost from blocking the defrosting device, i.e., the defrosting blade 4. The recess effectively prevents frost from accumulating over a large surface area of ​​the defrosting device 1. Thus, the blade 4 can always be moved along the pipe 6.

[0026] In one embodiment, the defrosting blade 4 has the shape of a quarter cylinder. The defrosting blade 4 extends, for example, partly around a longitudinal axis, and the protrusions extend perpendicularly to this longitudinal axis. The hollowed-out portion extends partly around the longitudinal axis.

[0027] The defrosting device 1 also includes a motorized actuator that moves the defrosting blade 4, for example along the longitudinal axis. This movement creates friction between the defrosting blade 4 and the frost, allowing it to detach or be torn away.

[0028] In one embodiment, the defrosting device 1 comprises only one defrosting blade 4. In another embodiment, the defrosting device 1 comprises at least four blades 4. The four blades 4 are then fixed together in pairs around the pipe 6, so that they can be moved simultaneously along the pipe 6. Such a configuration allows, in particular, easier maintenance. Indeed, only one defrosting blade 4 may require replacement or maintenance. Such a configuration also makes it possible to cover the entire periphery of the pipe 6.

[0029] In one embodiment, the actuator includes a threaded shaft 7. The de-icing blade 4 is then attached to the threaded shaft 7. For example, the blade 4 is attached by means of a support 5 or directly to the threaded shaft 7. The actuator includes an oblique element to the threaded shaft 7. The actuator also includes a motor that allows the oblique element to rotate. Thus, the threaded shaft 7 can rotate. The rotation of the threaded shaft 7 allows the de-icing blade 4 to move along the pipe 4. The actuator may include, for example, a means for transmitting power between the oblique element and the threaded shaft 7.

[0030] The invention also relates to a method for defrosting a fluid pipe 6 equipped with fins 2 by means of a defrosting device 1. This method then comprises a step of positioning a defrosting device 1 which includes at least one defrosting blade 4. This defrosting blade 4, as explained previously, cooperates with the fins, covering at least a portion of their surface. The defrosting blade 4 is not necessarily in direct contact with the surface of the fins 2 or the pipe 6. The defrosting blade 4 is sufficiently close to the periphery of the pipe 6 so that one of its ends can press against frost formed on the surface of the pipe 6 and / or the fins 2.

[0031] The method also includes a step of moving the defrosting device 1 along the pipe 6. During this movement, the frost is at least partially removed. This frost removal is achieved by the friction of the defrosting blade 4 against the frost or against the periphery of the pipe 6. This friction also allows some of the frost to detach. This frost removal can be achieved using a single defrosting blade 4 or several defrosting blades 4.

[0032] Thanks to the invention, frost can be eliminated on pipes 6 having complex shapes because the defrosting blade 4 cooperates with the pipe, in particular for example by means of protrusions described.

[0033] With reference to [Fig. 3], the invention also relates to a cryogenic fluid distribution system. In one embodiment, the system of the invention comprises at least one atmospheric heater 12. This heater 12 is equipped with at least one pipe 6 comprising several fins 2. The fins 2 are, for example, arranged projecting from an external periphery of the pipe 6. The system also includes the defrosting device 1 of the invention. The atmospheric heater 12 can be connected to a tank 11 storing the fluid. Thus, when a user draws fluid from the tank 11, the fluid then passes through the heater to reach the operating temperature. The defrosting device 1 ensures the efficiency of the atmospheric heater by preventing frost from accumulating around the pipes 6.

Claims

Demands

1. A method for defrosting a fluid pipeline (6) having fins (2) arranged projecting on an external periphery of the pipeline (6), and comprising frost on the surface of the pipeline (6), said method comprising: - a step of positioning a defrosting device (1) comprising at least one defrosting blade (4) cooperating with said fins (2), and - a step of moving said defrosting device (1) along said pipeline (6) so as to remove at least a part of the frost by mechanical action of said at least one defrosting blade (4) of said defrosting device (1) on at least a part of the surface of said fins (2).

2. De-icing device (1) for a pipe (6) comprising: - at least one de-icing blade (4) configured to cover at least part of the surface of the pipe (6), and comprising a draft angle on at least one end, - a motorized actuator for moving said at least one de-icing blade (4).

3. Defrosting device (1) according to claim 2, wherein said motorized actuator comprises: - at least one threaded shaft (7) carrying said at least one defrosting blade (4), - an oblique element to said threaded shaft (7), and - a motor enabling the rotation of the oblique element.

4. Defrosting device (1) according to claim 2 or 3 comprising at least four defrosting blades (4) being fixed together in pairs.

5. Cryogenic fluid distribution installation comprising: at least one atmospheric heater (12) of the fluid provided with at least one pipe (6) comprising at least several fins (2), characterized in that said installation comprises at least one defrosting device (1) according to any one of claims 2 to 4 arranged around said at least one pipe (6).

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