LIFE-SAVING FLOTATION DEVICE

Abstract

Lifesaving devices for providing flotation support to their users, and comprising a pressurized gas container, a flotation balloon and a valve for releasing the pressurized gas into the flotation balloon. The method of designing the devices comprises selecting a gas charge for the pressurized gas container, having a high molecular weight, such that, for a specific lifesaving device, the diffusion of the gas charge through the walls of the pressurized gas container are reduced, as compared with a gas charge having a lower molecular weight. The device therefore has a longer shelf life before the need to recharge the gas fill. The use of such a high molecular weight gas also reduces the diffusion of the gas charge through the walls of the flotation balloon, such that the device fulfils its purpose of supporting the user in water for a longer period of time.

Claims

1. A method for increasing the shelf life of a life-saving flotation device, comprising the steps of: providing a life-saving flotation device comprising: a pressurized gas container; at least one flotation chamber; and an actuating valve connecting the pressurized gas container to the at least one flotation chamber; and selecting a gas fill for the pressurized gas container, the gas having a molecular size such that the diffusion rate of the gas fill out of the pressurized gas container is sufficiently low that the pressurized gas container maintains a predetermined charge of gas for a predetermined minimal time requirement.

2. A method according to claim 1, wherein the gas fill selected has a molecular weight of more than 100 gm/mole.

3. A method according to claim 1, wherein the gas fill selected has a molecular weight of more than 60 gm/mole.

4. A method according to claim 1, wherein the pressurized gas container comprises a single polymer layer.

5. A method according to claim 1, wherein the gas fill selected further results in the at least one flotation chamber maintaining a volume of the gas sufficient to support the user of the device for a predetermined minimum time requirement.

6. A method according to claim 1, wherein the gas fill selected comprises at least one of R1234ze(E), R1234yf, R1224yd(Z) or R515B mixture.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which FIG. 1 shows a schematic representations of a prior art flotation appliance or device, which benefits from the use of gases having large molecular dimensions to ensure low diffusibility through the gas containers of the device.

DETAILED DESCRIPTION

[0029] Reference is made to FIG. 1 which illustrates schematically, a typical flotation device in the form of a life-vest 1, such as is used on aircraft or ships, having a compressed gas container 2, and a flotation chamber or chambers 3, the compressed gas container being connected to the flotation chamber(s) by means of an actuation valve 5, which can be operated either by the user of the device, such as using an activation trigger cord 4 or a lever (not shown in FIG. 1), or which can be operated automatically, using a controller 6, by means of a sensor, when the flotation device finds itself located in a water volume, such that the sensor is operated.

[0030] The compressed gas container 2 can be formed of a vessel having thin metallic walls, or, more advantageously to provide a lighter and more readily storable, a vessel formed with polymer walls, manufactured at low cost by a plastic forming operation, on condition that the polymer vessel can withstand the pressure of the gas charge even at very high environmental temperatures. The inflatable flotation chamber or chambers 3 can be in the form of one or more pouches as shown in FIG. 1, or envelopes or an inflatable collar, or the like, as is well known in the numerous references for such devices. Like the compressed gas container 2, the flotation chambers 3 can be manufactured either from a thin metallic foil, or more practically, of a bag-like vessel constructed of a thin polymer layer. The actuation valve 5 should advantageously have a polymer seating closure, such as a plate or needle-like cone, which could be metallic to ensure good closure, interfacing with a soft polymer seat, such as an O-ring, to ensure minimal leakage or permeation of the charge gas through the valve, before actuation of the device is needed. Although the simplest form of the life-vest may be manually operated without any electronic control, there has been described an Intelligent Inflatable Life Vest in WO 2020/133684 to Shenzhen Qizhen Security Technology Ltd., in which the controller 6 operates the inflation valve mechanism, optionally based on a water depth sensor or a user operated switch.

[0031] Although the flotation device of FIG. 1 may be used with any compressible gas suitable for the purpose, all other things being equal, the use of a compressed gas fill having a large molecular size, generally resulting from a large molecular weight, results in a lower level of diffusion of the gas out of the pressurized gas container, than a gas having a smaller molecular size. The same advantage applies to the gas fill of the flotation chambers 3 when the device is actuated, with the gas remaining in the flotation chambers for a longer period of time than a gas having a smaller molecular size. As is known from published WO 2020/208636 for Emergency Flotation Device using Compressed Gas, and from other prior art sources, such large molecular weight gases can include a gases developed for refrigeration and air conditioning applications, such as R1234ze(E) or R1234yf, R1224yd(Z) or the mixture known as R515B. The gas R-12234z(E) has a molecular weight of 114 gm/mole, and a corresponding molecular size, and that of the mixture R-515B has a molecular weight of 117.5 gm/mole, and a corresponding molecular size, as compared to the molecular weight of carbon dioxide, which is 44 gm/mole, with a corresponding substantially smaller molecular size. Because of the lower pressures to which these gases must be pressurized, their use provides another advantage in that the gas container may be manufactured with a much thinner wall dimension, and of polymer material, than the gas container of a low molecular weight gas fill.

[0032] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. Furthermore, it is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.