AU2005100115A4

AU2005100115A4 - Inflation Medium

Info

Publication number: AU2005100115A4
Application number: AU2005100115A
Authority: AU
Inventors: Gregory J Moore
Original assignee: JADEFOIL
Current assignee: JADEFOIL
Priority date: 2005-02-09
Filing date: 2005-02-09
Publication date: 2005-03-24
Anticipated expiration: 2013-02-09

Description

DESCRIPTION

Brief Description of Invention The invention relates to a more reliable and safer gas or liquid propellant for use in borehole plugs.

The invention is a gas or liquid propellant that is non flammable, non toxic and has a low vapour pressure and thus a higher working temperature.

Brief Description of Drawings Embodiments of the present invention will now be described with reference to the accompanying drawings wherein: Figure 1 is a plan view of an inflatable borehole plug consists of a gas tight bladder or bag figure 1 with a pressure can or aerosol can sealed inside the gas tight bladder usually by means of heat sealing or welding of the gas tight bladder.

The pressure canister or aerosol can is filled with a suitable propellant and in some cases a further liquid that may delay the release of propellant or increase the density of the propellant. The inflatable borehole is operated via a latch on the pressure canister or aerosol can. Thereby releasing the inflating agent and thus inflating the borehole plug.

After operation of the latch the inflatable borehole plug is usually lowered into the borehole on a string or similar device and held in place until the inflatable plug inflates and secures itself against the walls of the borehole.

Detailed Description of Preferred Embodiment This invention is for a low vapour pressure non flammable propellant to be used in an inflatable borehole plug which uses a pressurised canister such as an aerosol can to inflate the borehole plug.

Inflatable borehole plugs are described in AU 656051 Typically refrigerant gases are used as non flammable propellants HFC-134a, 1, 1, 1, 2tetrafluoroethane, HFC-152a, HFC 125 and alike. There are also those propellants that have been deemed to affect the ozone layer such as CFC-12, R-1 1,R-12, R-500, Dichlorodifluoromethane, HCFC-22,HFC-22, HFC-123, HFC-227 and alike. Other non flammable gases that are available but not practical for use are carbon dioxide, nitrogen, helium.

Typically at 20 Degrees Celsius the vapour pressure of HFC-134a is over 480 Kilopascals and further increasing to over 1200 Kilopascals at 50 degrees Celsius. Similarly most of the non flammable gases have higher vapour pressures with the exception of some of the older refrigerant gases such as R12 which are being phased out due to effects on the earth?s ozone layer.

First Preferred Embodiment A lower vapour pressure can be obtained with HFC-134a, 1, 1, 1, 2-tetrafluoroethane by mixing the 1, 1, 1, 2-tetrafluoroethane with the lower alcohols, ketones chlorinated solvents. A typical mixture will comprise of 5 percent by weight of the lower alcohols mixed with the 1, 1, 1, 2tetrafluoroethane. Mixtures in other proportions may also be used to lower the vapour pressure of 1, 1, 1, 2-tetrafluoroethane and other non flammable gases.

Typically the vapour pressure of the can be lowered so that at 20 degree Celsius the vapour pressure is less than 460 Kilopascals and at 50 degrees Celsius less than 1200 Kilopascals A common mixture comprising of 6 percent ketones/chlorinated solvents will reduce the vapour pressure of to 460 Kilopascals at 20 degrees Celsius and 1120 Kilopascals at 50 degrees Celsius.

The above describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope and spirit of the present invention.

Claims

1. An inflatable borehole plug with a non flammable inflation liquid or gas having a vapour pressure of less than 1200 Kilopascals at 50 degrees Celsius.

2. An inflatable borehole plug as in Claim 1 where the propellant is a blend of 1, 1, 1, 2- tetrafluoroethane and lower alcohols, ketones or chlorinated solvents.

3. An inflatable borehole plug with a non flammable inflation liquid or gas having a vapour pressure of less than 470 Kilopascals at 20 degrees Celsius.

4. An inflatable borehole plug as in Claim 3 where the propellant is a blend of 1, 1, 1, 2- tetrafluoroethane and lower alcohols, ketones or chlorinated solvents. A method of inflating a borehole plug by a non flammable flow of gas with a vapour pressure of less than 1200 Kilopascals at 50 degrees Celsius from a canister sealed within a gas tight bag or bladder; said method including the steps of: a) Operating the pressure release mechanism b) Lowering or moving inflatable borehole plug into position c) Waiting until the inflatable borehole plug has inflated and engaged the walls of the borehole.