It is common practice across numerous industries to store a volume of fluid ready for use upon the turn of a tap. The fluid may be stored remote from the outlet and piped to the outlet, or may be stored in close proximity to the outlet.
In one application the stored fluid is required for use in flushing stations. Flushing stations are used for the emergency treatment of the eyes and body of a person who has been exposed to materials and or environments which may cause injuries. A flushing station typically comprises an eye bath, or a face wash basin or a deluge shower or a combination of these elements. These flushing stations are a necessary safety installation in many industries, and are critical in areas where an operator may be exposed to materials or environments which may cause injuries.
In some jurisdictions Governments provide standards which industries are recommended to comply with in relation to the number and placement of the flushing stations. These standards also recommend a tepid temperature range for the fluid exiting the flushing station. For instance, Australian Standard AS4775-2007 Emergency eyewash and shower equipment advises “there is no medically or industry accepted standard for the temperature range of fluids that may be defined as tepid. The term is used to allow the acceptable temperature range for a particular workplace environment to be decided based on factors such as the geological location of the equipment, the location of the equipment within the facility and the types of hazardous materials to which the person may be exposed. A recommended temperature range for tepid fluids is 15.6° C. to 37.8° C.
Flushing stations are essential at all worksites where hazardous materials may exist. Numerous worksites are located in regions throughout the world where ambient temperatures exceed the upper limit of the temperature range described as tepid. These high ambient temperatures heat the fluid in the fluid piping and storage system, especially if the fluid is in a pipe exposed to direct sunlight.
A person exposed to a flushing fluid delivered at a temperature above the upper limit for a tepid fluid is in danger of being injured by the heat contained in the flushing fluid. Australian Standard AS4775-2007 states in clause D5 Flushing Fluid Temperature “Continuous and timely irrigation of affected tissues for the recommended irrigation period are the principal factors in providing first aid treatment. Providing flushing fluid at temperatures conducive to use for the recommended irrigation period is considered an integral part of providing suitable facilities. Medical recommendations suggest a flushing fluid at tepid temperatures be delivered to affected chemically-injured tissue. Temperatures in excess of 38° C. have proven to be harmful to the eyes and can enhance chemical interaction with the eyes and skin. During design and installation, the effects of exposure of piping to sun, radiant heat or other heat sources should be considered, and suitable control measures should be introduced to avoid any risk of scalding.”
Currently there are no suitable systems available which will ensure tepid fluid is available to the flushing station as and when required when the temperature of the flushing fluid in the supply pipework to the flushing station is above the recommended range of temperatures for tepid fluids.
One system which has been in use utilises a relief valve positioned close to the flushing station outlet. The relief valve is typically set to purge fluid within the pipe when the fluid reaches 39′C. The valve will remain open until the temperature drops to 29° C. In hot environments, this often means that the relief valve is open all day, constantly discharging fluid from the pipe. It is undesirable and often a safety hazard to discharge fluid, generally water, in this way. If the relief valve is subsequently shut off the fluid in the pipe can often be heated above the recommended range of temperatures for tepid fluids.
Another system uses a chiller unit placed in-line with a pipeline. As the fluid passes through the pipe the chiller acts as a heat exchanger to chill the fluid. As the chiller requires significant power it must be wired back to a main electrical board which in itself can be a costly process. Furthermore, as the pipework servicing the flushing station is generally exposed to atmospheric conditions, a chiller unit will take a few minutes of operation before the fluid held in the pipework is discharged and the chilled fluid within the recommended range of temperatures for a tepid fluid can be delivered This system does not mitigate the risk of a person injuring themselves as the initial fluid delivered to the flushing station may be at a temperature which is above the recommended range of temperatures for a tepid fluid, possibly leading to further injury.
Another system uses a refrigerated pressure vessel to deliver cooled fluid to a flushing station. These vessels are quite large and often difficult to accommodate in the areas where flushing stations are required. Furthermore, the need to pressurise and insulate a large vessel is both difficult and expensive. In addition, it is difficult to control the temperature of the fluid being delivered to the flushing station as the fluid supplied to the pressure vessel during operation of the flushing station will mix with the cooled fluid in the tank in a non-uniform manner. As a result, the fluid delivered to the flushing station may fluctuate in temperature and may exceed the recommended range of temperatures for a tepid fluid.
The preceding discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.