AN APPARATUS AND PROCESS FOR RECOVERING PROPELLANT AND

PRODUCT FROM AEROSOLS Technical Field This invention relates to an apparatus and process for - 5 recovering propellant and product from aerosols, which propellant and product may be in a gaseous form. In this 'i specification gaseous or gaseous materials means existing as a gas or a liquid which evaporates into a gas. Moreover, reference to aerosols is reference to a pressurized container 10 having gaseous materials therein under pressure so that upon opening a valve the contents, or a part thereof, of the container are emitted under pressure.

With the ever increasing demands for the protection of the environment from waste materials emitted during the 15 manufacture of various products, it has become necessary to ensure that such waste materials are released into the environment in an environmentally friendly condition.

During the production of aerosol cans of the type used in hair sprays, insect killers, and paint sprays, for 20 example, it is the usual practice to test cans which have been prepared for sale to the general public so that the safety of the public is ensured both from overpressurising of containers and leaky containers. Any rejected aerosol containers have in the past been fed to a shredding machine 25 which shredded the cans releasing the contents thereof into the atmosphere or into water which is released into the drainage system. Whilst some products within aerosol containers may be harmless, particularly to human beings, the chemicals when released into the environment are extremely 30 toxic to fish and other wildlife.

Summary This invention relates to an apparatus for recovering f the contents of an aerosol container comprising means for supporting a rejected aerosol container, cutting means i 35 located in the region of the container for creating an aperture in the body of the container and means for collecting discharged propellant gas and product emitted from the container upon the piercing thereof.

Disclosure of Invention In one embodiment of the present invention the means for connecting discharged propellant gas and product emitted from the container comprises a collection tank having an extractor for immediately removing the propellant gas. The product is collected in the tank and subsequently pumped from the tank into a reclamation unit. The tank is conveniently provided with a float switch to energize a pump to pump out the product when the product reaches a predetermined level. Preferably, the rejected aerosol containers are supported in a chute of circular cross section. The chute is preferably provided with a plurality of stops and a slit through which the piercing device, conveniently a rotary device, extends through the slit and pierces a container held in the correct position in the circular chute by one of the stops. Conveniently, a sealing pad is located to force a can in the region of the ducting against the chute wall so that propellant gas and product within the container is emitted, upon piercing of the container, directly into the ducting and subsequently the collection tank.

According to another aspect of the present invention there is provided a process for recovering the contents of an aerosol container, including locating an aerosol container adjacent a piercing device, container which are discharged from the container under pressure.

Brief Description of the Drawing The present invention will now be described by way of example with reference to Figure 1 which is a diagrammatic side elevational view of one form of apparatus according to the present invention.

Best Mode for Carrying Out the Invention The aerosol recovery apparatus shown in Figure 1 comprises a container chute 1, a collection tank 2, ducting 3 located between the container chute and recovery tank 2 and a piercing device 4 located in the ducting adjacent the container chute.

The container chute 1 is an elongate tube of circular crosssection having an internal diameter which is sufficient to allow standard aerosol container 5, to slide there through

under the force of gravity. To achieve the gravitational movement the chute is located at approximately 45° to the horizontal. The container chute is provided with at least two stops 6, 7, for securing aerosol containers in a particular location within the chute during operation of the apparatus. Stop 6 serves to hold a container within the chute adjacent the ducting 3 so that when a container is pierced by the piercing device 4, the gas and product discharged upon piercing passes through a slit (not shown) in the chute wall into the ducting 3. Simultaneously, stop 7 is operated to prevent the next adjacent container from passing into the ducting region and engaging with a container which has just been pierced. Conveniently stop 7 is adjustable along the length of the container chute to accommodate containers of varying heights.

In addition to the stops 6, 7, the container chute is also provided with a sealing pad 8 and a roller switch 9, both of which are located between the stops 6 and 7. The pad 8 is operable to push a container against the wall of the container chute so that when a container is pierced the contents of the container are emitted directly through the slit (not shown) in the chute wall and into the ducting 3. The roller switch 9 is effective to actuate the piercing device 4. Once a container is correctly located in the chute against stop 6 the piercing device which is a rotary device is energized and rotates to make a small slit in the wall of the container.

When the contents of a container have been discharged into the ducting 3, stops 6 and 7 are removed and the emptied container is allowed to slide out of the outlet 10 of the container chute and into a collection bin 11 such as a skip. The next adjacent container meanwhile is allowed to pass stop 7 until it reaches stop 6 and is held in position against the chute wall for piercing and discharge of gas into the ducting 3.

As previously described the ducting 3 feeds the discharged contents of a pierced container to the collection tank 2 which is vented to the atmosphere through a tube 12 to provide air to balance a vacuum effect upon discharge of a

container. When the discharged propellant gas and product enter the tank 2, the gas is immediately removed by an extractor fan 13 and fed to a standard gas reclamation unit not further described. The liquid product collects within the tank 2 which is provided with a float switch 14 so that when the product rises within the tank to a predetermined level a pump 14 located within the tank is energized and pumps the product from the tank into another standard product reclamation unit not further described. The apparatus and process disclosed advantageously allows rejected aerosol containers to be destroyed safely and efficiently by collecting and reintroducing into the filling process for aerosol containers propellant gas and product whilst simultaneously avoiding entry of the propellant gas and products into the atmosphere or into water which may be discharged into a conventional drainage or other water systems such as rivers. Therefore, there is provided an environmentally friendly process of producing aerosol containers which substantially reduces the cost of disposing of rejected aerosol containers and hence the overall manufacturing process of such aerosol containers.

Industrial Applicability The present invention is useful in the manufacture of products packaged in aerosol cans and in particular in the recovery of both the propellant and product contained in scrap aerosol cans in a manner which minimizes the release of these materials to the environment.