Air canopy ventilation system

A canopy system for use in combination with equipment producing fumes whose escape into the environment is not desired, said system comprising in combination:

• means defining a volume for receiving said fumes and an access opening for affording access to said volume from said environment, said access opening having an upper edge, a lower edge and opposite side edges;
• means having an inlet communicating with said volume, filter means and an outlet, said inlet extending lengthwise of and in spaced relationship to said upper edge;
• suction means communicating with said outlet for drawing fumes and air from said volume successively through said inlet, said filter means and said outlet and discharging under pressure air filtered by said filter means;
• a discharge for discharging a portion of said filtered air to said environment;
• means receiving an other portion of said filtered air for creating an air curtain directed upwardly from adjacent said lower edge and across said access opening between said side edges towards said inlet;
• and
• means for supplying air to said volume from said environment incident to a decrease in pressure existing within said volume relative to the pressure existing in said environment, and
• said means defining said volume includes a vortex chamber extending lengthwise adjacent said upper edge and opening towards said inlet, and a wall extending between said vortex chamber and said inlet, said wall dividing fumes rising within said volume for flow rearwardly within said volume towards said inlet and forwardly within said volume towards said vortex chamber, and said vortex chamber imparts downwardly and rearwardly movement to said fumes.

A canopy system for use in combination with equipment producing fumes whose escape into the environment is not desired, said system comprising in combination:

• means defining a volume disposed above said equipment for receiving said fumes and an access opening adjacent one side of said equipment for affording access to said volume from said environment, said access opening having an upper edge, a lower edge and opposite side edges;
• having an inlet, filter means and an outlet, said inlet and said access opening communicating with said volume adjacent horizontally opposed sides of said equipment with said lower edge being disposed vertically adjacent said equipment and said inlet being disposed vertically remote from said equipment;
• suction means communicating with said outlet for drawing fumes and air from said volume successively through said inlet, said filter means and said outlet and discharging under pressure air filtered by said filter means;
• a discharge for discharging a portion of said filtered air to said environment;
• means receiving an other portion of said filtered air for creating an air curtain directed upwardly from adjacent said lower edge and across said access opening between said side edges towards said inlet;
• and
• means for receiving a further portion of said filtered air for creating a filtered air flow directed from adjacent said lower edge towards said inlet and intermediate said air curtain and said equipment.

A method of preventing escape into the environment of fumes generated by equipment, said method comprising:

• providing an enclosure defining a volume for receiving said fumes and an access opening for affording access to said volume, said access opening having an upper edge, a lower edge and opposite side edges;
• providing air filtering means having an inlet communicating with said volume remotely of said access opening, air filter means and an outlet;
• providing suction means connected to said outlet for drawing said fumes and air from said volume through said inlet and through said filter means and for discharging filtered air under pressure;
• conducting a portion of said filtered air to said environment in an amount exceeding a maximum volume of fumes expected to be generated by said equipment;
• conducting a remaining portion of said filtered air in an amount less than said portion to said lower edge for creating an air curtain extending upwardly across said access opening between said opposite side edges for flow into said volume and to said opposite side edges for creating flows of filtered air into said volume adjacent opposite sides of said air curtain disposed adjacent said opposite side edges;
• providing a makeup air inlet means extending along said lower edge for creating a flow of air from said environment into said volume between said air curtain and said equipment in response to reduction in pressure within said volume incident to withdrawal of said fumes and air from said volume in an amount exceeding an amount of said remaining portion of said filtered air introduced into said volume.

A method of preventing escape into the environment of fumes generated by equipment, said method comprising:

• providing an enclosure defining a volume for receiving said fumes and an access opening for affording access to said volume, said access opening having an upper edge, a lower edge and opposite side edges;
• providing air filtering means having an inlet arranged to communicate with an upper extent of said volume, air filter means and an outlet, said inlet being disposed remotely of and extending lengthwise of said upper edge;
• providing suction means connected to said outlet for drawing said fumes and air from said volume through said inlet and through said filter means and for discharging filtered air under pressure;
• providing a filtered air discharge opening for discharging a portion of said filtered air to said environment;
• providing means for conducting an other portion of said filtered air for creating an air curtain extending along said lower edge and directed upwardly across said access opening between said opposite side edges for receipt within said volume and for creating air flows into said volume from adjacent said opposite side edges;
• providing a makeup air inlet extending lengthwise of said lower edge for permitting flow of air from said environment into said volume adjacent an inner boundary of said air curtain facing away from said environment;
• correlating the amount of said filtered air discharged from said suction means, the amount of said portion of said filtered air discharged to said environment, the amount of said other portion of said filtered air conducted for creating said air curtain and said air flows and the size of said makeup air intake to prevent movement of said air curtain from engagement with said upper edge incident to fluctuations in the volume of said fumes generated by said equipment.

A method of preventing escape into the environment of fumes generated by equipment, said method comprising:

• providing an enclosure defining a volume for receiving said fumes and an access opening for affording access to said volume, said access opening having an upper edge, a lower edge and opposite side edges;
• providing air filtering means having an inlet arranged to communicate with an upper extent of said volume, air filter means and an outlet, said inlet being disposed remotely of and extending lengthwise of said upper edge;
• providing suction means connected to said outlet for drawing said fumes and air from said volume through said inlet and through said filter means and for discharging filtered air under pressure;
• discharging a portion of said filtered air to said environment in an amount exceeding the maximum amount of fumes expected to be generated by said equipment;
• conducting an other portion of said filtered air for creating an air curtain extending along said lower edge and directed upwardly across said access opening between said opposite side edges for receipt within said volume and for creating air flows into said volume from adjacent said opposite side edges;
• and
• conducting a further portion of said filtered air for creating a flow of filtered air extending along said lower edge and directed into said volume intermediate said air curtain and said equipment.