Device for securing a leak, premises equipped with such a device and associated leak-securing method

Abstract

The invention relates to a device for securing a leak of fluid from equipment containing a pressurised fluid. The device comprising a gas-tight containment device disposed around the equipment and defining a volume, Vconf, between the inner surface of the sealed containment device and the outer surface of the equipment. A vent is formed by one or more ports in the sealed containment device, each port being defined by its cross-section and shape. According to the invention, the volume, Vconf, the cross-section and the shape of each port are configured such that, in the event of a leak of flow rate Qf, the fluid is discharged through each port in the form of a turbulent jet.

Claims

1. A device for securing a leak of a fluid that may occur in a pressure equipment containing that fluid, in which the device for securing a leak is configured to secure a leak having a given leakage flow rate a fluid Q.sub.f said securing device comprising: a fluidtight containment device, arranged around the pressure equipment and defining a volume V.sub.conf between an internal surface of said fluidtight containment device and an external surface of the pressure equipment; a vent made up of one or more orifice(s) in the fluidtight containment device, each orifice being defined by its cross section and by its shape; and in which the volume V.sub.conf, and the cross section and the shape of each orifice are configured so that in the event of a leak with a flow rate Qf, the fluid is discharged through each orifice in the form of a turbulent jet and in which at least one orifice in the fluidtight containment device is extended in a direction of discharge of the jet of fluid by a dilution device able to dilute the fluid of the jet using a gas situated beyond the external surface of the fluidtight containment device.

2. The device for securing a leak of a fluid as claimed in claim 1, in which the fluid is a gas.

3. The device for securing a leak of a fluid as claimed in claim 1, in which the fluid is a liquid.

4. The device for securing a leak of a fluid as claimed in claim 1, in which the fluidtight containment device is formed essentially of a wall placed on a plinth on which the pressure equipment rests, and in which the wall is made of a deformable material.

5. The device for securing a leak of a fluid as claimed in claim 1, in which the shape of the orifice in the fluidtight containment device is multilobed.

6. The device for securing a leak of a fluid as claimed in claim 1, in which the dilution device is a Venturi-effect mixer or a succession of Venturi-effect mixers.

7. The device for securing a leak of a fluid as claimed in claim 1, in which one or more component(s) of the dilution device is/are extended in a direction of discharge of the jet of fluid by a grating that generates a turbulence in the fluid of the jet.

8. A premises equipped with at least one device for securing a leak of a fluid as claimed in claim 1.

9. The premises equipped with at least one device for securing a leak of a fluid as claimed in the claim 8, comprising a plurality of walls and, in at least one wall, an opening device that can be actuated by a thrust exerted by the turbulent jet of fluid during the leak.

10. A method for securing pressure equipment in the event of a leak of a pressurized fluid therefrom, the method comprising: implementing a device for securing a leak of a fluid as claimed in claim 1; allowing the fluid to spread out in the gastight containment device; and allowing the fluid to discharge in the form of a turbulent jet through each orifice of the vent.

11. The securing method as claimed in claim 10, comprising the following additional step: allowing the fluid to become diluted beyond an orifice in a direction of discharge of the jet of fluid by virtue of a dilution device so as to dilute the fluid of the jet with a gas situated beyond the external surface of the fluidtight containment device.

12. A method for calculating the characteristics of a device for securing a leak of a fluid as claimed in claim 1, implemented by computer processing means in which: inputting a fluid leakage flow rate Qf; inputting the geometric characteristics of the pressure equipment; calculating by iteration and/or by optimization the geometric characteristics of a gastight containment device and of the vent such that the fluid is discharged through each orifice of the vent in the form of a turbulent jet are calculated by iteration and/or by optimization.

13. The securing method as claimed in claim 10, wherein the use of at least one leak securing device is under conditions in which the outdoor temperatures are below or equal to −40° C.

14. The device for securing a leak of a fluid as claimed in claim 4, in which the deformable material is a composite material containing carbon fiber and/or aramid fiber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The following examples illustrate the present invention.

(2) The invention will be better understood if reference is made to the attached drawings in which:

(3) FIG. 1 schematically depicts a side view of one embodiment of a leak securing device according to the invention protecting equipment;

(4) FIG. 2 schematically depicts a plan view of one embodiment of a leak securing device according to the invention protecting equipment;

(5) FIG. 3 schematically depicts a view in section on III-III of one embodiment of a leak securing device according to the invention protecting equipment;

(6) FIG. 4 schematically depicts a view in section on IV-IV of one embodiment of a leak securing device according to the invention protecting equipment;

(7) FIG. 5 schematically depicts a front elevation of one embodiment of a leak securing device according to the invention protecting equipment;

(8) FIG. 6 schematically depicts an isometric view of one embodiment of a leak securing device according to the invention protecting equipment;

(9) FIG. 7 schematically depicts part of an embodiment of a leak securing device according to the invention, in plan view.

(10) It should be noted that the components of the device depicted have not necessarily been drawn to scale and that the sole purpose of the figure is to make the present invention easier to understand.

DETAILED DESCRIPTION OF THE DRAWINGS

(11) In the example depicted in FIGS. 1 to 6 pressure equipment 1 is illustrated, protected by a securing device according to the present invention, in which said securing device comprises a gastight containment device 3 arranged around the equipment 1 on a plinth 2.

(12) This fluidtight containment device 3 comprises a vent 4 situated in its upper part.

(13) For the purposes of the present description, the line corresponding to the bottom of the plinth 2 on which the pressure equipment 1 rests is defined as a horizontal reference line; this line may notably correspond to the ground on which the plinth 2 rests. An up-and-down direction is defined along a line perpendicular to said horizontal line, where the top is situated above the vent 4 and the bottom under the plinth 2.

(14) A first component is considered to be situated above or higher up than a second component if the first component is positioned closer to the top than the second component; likewise, a first component is considered to be below or lower down than a second component if the first component is positioned closer to the bottom than the second component.

(15) In order to dimension the securing device according to the present invention, consideration is given to a given leakage flow rate Q.sub.f of pressurized fluid. This leakage flow rate Qf is defined as a function of the characteristics of the equipment that is to be protected and is generally defined by services responsible for the safety of pressure equipment. Some of the parameters taken into consideration in defining the leakage flow rate Qf include, for example: the type of fluid, the dimensions of the equipment that is to be protected, the pressure of the fluid when the equipment is in operation, the temperature of the fluid when the equipment is in operation.

(16) The volume V.sub.conf is defined between the internal surface of said fluidtight containment device 3 and the external surface of the pressure equipment 1 containing that fluid.

(17) The vent 4 is made up of one or more orifice(s) in the fluidtight containment device, each orifice being defined by its cross section and by its shape. In the case depicted, there is one single circular orifice in the fluidtight containment device and the vent and the orifice are therefore the same thing. However, numerous other forms of embodiment may be envisioned, notably in which the vent 4 is made up of several orifices and/or in which the orifices are not circular but may have other shapes, such as notably the shape of an ellipse, a square, a parallelepipedal slot. More complex shapes may also be chosen.

(18) The volume V.sub.conf the cross section and the shape of the orifice of the vent 4 are configured so that in the event of a leak with a flow rate Qf, the fluid discharges through the orifice in the form of a turbulent jet. In the event of there being a plurality of vent orifices, the volume V.sub.conf, the cross section and the shape of the orifices of the vent are configured so that in the event of a leak with a flow rate Qf, the fluid discharges through each orifice in the form of a turbulent jet.

(19) In the event of a leak of a fluid from a component of the pressure equipment 1 implementing the leak securing device described hereinabove: the pressurized fluid extends into the gastight containment device 3; then the pressurized fluid discharges in the form of a turbulent jet through the orifice of the vent 4.

(20) The volume V.sub.conf allows the pressurized fluid first of all to expand into the volume; the pressurized fluid is therefore not in the presence of the environment surrounding the gastight containment device; it very rapidly fills the volume V.sub.conf and is confined in the first few moments after a leak; as soon as the volume V.sub.conf is full, the pressurized fluid discharges in the form of a turbulent jet through each orifice of the vent 4.

(21) According to one exemplary embodiment, the fluid is a gas, notably selected from one or more gases of the list consisting of methane, propane.

(22) According to another exemplary embodiment, the fluid is a liquid, notably selected from one or more liquids of the list consisting of a liquefied gas.

(23) By way of example, the fluid is at a pressure of between 100 and 1000 bar in the equipment when the equipment is in operation.

(24) By way of example, the given leakage flow rate Qf is between 1 and 10 kilograms per second (kg/s).

(25) By way of example, the Reynolds number of the fluid discharging through the orifice in the form of a turbulent jet is between 10.sup.5 and 10.sup.6.

(26) According to one embodiment of the example depicted in FIGS. 1 to 6, the fluidtight containment device is formed essentially of a wall placed on a plinth 2 on which the pressure equipment rests, in which the wall is made of a deformable material, for example a composite material containing carbon fiber and/or aramid fiber, notably Kevlar® or Nomex®. Choosing a deformable material allows controlled deformation of the fluidtight containment device when the pressurized fluid is released; choosing a composite material containing carbon fiber and/or aramid fiber means that the high loadings to which the containment device may be subjected can be withstood. This is because these materials are capable of deforming to a large extent without tearing. The deformable material is, for example, supported by a metallic structure.

(27) Furthermore, the orifice in the fluidtight containment device is extended in the direction of discharge of the jet of fluid by a dilution device able to dilute the fluid of the jet using a gas situated beyond the external surface of the fluidtight containment device. The dilution device is a succession of two Venturi-effect mixers 51, 52. The surface of the Venturi-effect mixer(s) may be rough.

(28) These various means make it possible to increase the turbulence of the fluid in the jet and to increase the dilution of the pressurized fluid with the environment surrounding the gastight containment device.

(29) It is possible to increase the turbulence still further by adding to the dilution device a grating that is placed in the direction of discharge of the jet of fluid.

(30) In one embodiment depicted in FIG. 7, the shape of the orifice 4 in the fluidtight containment device is multilobed. The cross section of the two Venturi-effect mixers 51, 52 is also multilobed. These multilobed shapes make it possible to increase still further the turbulence and the dilution of the pressurized fluid with the environment.

(31) According to one embodiment that has not been depicted, the leak securing device according to the present invention and described hereinabove is installed in a premises, for example in the form of a shed, which comprises a plurality of walls. An opening device that can be actuated by the thrust exerted by the turbulent jet of fluid during the leak, for example a valve, is arranged in the wall situated in the direction of the turbulent jet of fluid leaving the orifice. This opening device is arranged in a wall in line with the orifice; the turbulent jet of fluid leaving the orifice actuates it by thrust when a leak occurs, thus allowing the pressurized fluid to be discharged from the premises.

(32) The present device is particularly well suited to cases in which the pressurized fluid is an explosive gas (for example methane or propane) because it first of all allows the gas to become concentrated, thereby avoiding the risks of explosion, and then allows the gas to be diluted with the environment surrounding the fluidtight containment device; this environment is generally made up of air. In this way it is possible to prevent the pressurized fluid from remaining in a critical concentration range within which the risks of explosion are at a maximum.

(33) However, the invention is not restricted to equipment containing a pressurized explosive gas but may find applications in equipment containing some other pressurized fluid.

(34) The embodiments above are intended to be illustrative and not limiting. Additional embodiments may be within the claims. Although the present invention has been described with reference to particular embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

(35) Various modifications to the invention may be apparent to one of skill in the art upon reading this disclosure. For example, persons of ordinary skill in the relevant art will recognize that the various features described for the different embodiments of the invention can be suitably combined, un-combined, and re-combined with other features, alone, or in different combinations, within the spirit of the invention. Likewise, the various features described above should all be regarded as example embodiments, rather than limitations to the scope or spirit of the invention. Therefore, the above is not contemplated to limit the scope of the present invention.