Ovens

Claim 2

A heat exchange apparatus comprising: a. a body of low thermal mass forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, b. first manifolds located between said side walls, c. ports in said manifolds for admitting gas to the zone of the tunnel between the manifolds, d. means for varying the temperature of gas admitted into said zone, e. first drive means for driving gas past said temperative varying means and through said manifolds, f. outlet means positioned opposite said ports to permit flow of gas across said zone and from said tunnel, g. second drive means for drawing gas from said zone through said outlet means and for driving that gas to the input os said first drive means and to exhaust means, and h. conveying means for conveying atricles through said tunnel, said conveying means including a flexible endless conveying surface and supporting means therefor provided on each manifold.

Claim 3

Apparatus as claimed in claim 1 comprising second manifolds mounted between said side walls and connected with said outlet means and said second drive means.

Claim 4

Apparatus as claimed in claim 1 comprising control means for controlling the proportion of gas from said second drive means which is fed to the inlet of said first drive means and to said exhaust means.

Claim 5

Apparatus as claimed in claim 3 comprising means for feeding fresh gas to the inlet of said first drive means at a rate which is substantially equal to the rate at which gas is fed to said exhaust means.

Claim 6

Apparatus as claimed in claim 3 wherein said control means includes a control valve connected between said first and second drive means.

Claim 7

Apparatus as claimed in claim 5 wherein said control valve is a fluidic valve which includes means for feeding fresh gas to the inlet of said first drive means.

Claim 8

Apparatus as claimed in claim 6 wherein said control means includes a water vapour detector in said zone and connected to control said valve.

Claim 9

Apparatus as claimed in claim 1 wherein said first and second drive means and said heating means are positioned within said tunnel.

Claim 10

Apparatus as claimed in claim 1 wherein said ports are positioned to admit gas into said zone both above and below said conveying surface, said ports being adapted to admit different amounts of gas above said conveying surface as below said conveying surface.

Claim 11

An oven comprising first and second modules each comprising: a. a body of low thermal mass forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, b. first manifolds located between said side walls, c. ports in said manifolds for admitting gas to the zone of the tunnel between the manifolds, d. heating means for gas admitted into said zone, e. first drive means for driving gas past said heating means and through said manifolds, f. outlet means positioned opposite said ports to permit flow of gas across said zone and from said tunnel, g. second drive means for drawing gas from said zone through said outlet means and for driving that gas to the inpUt of said first drive means and to exhaust means, and h. conveying means for conveying articles through said tunnel, said conveying means including a flexible endless conveying surface and supporting means therefor provided on each manifold, said oven also including means provided on said first and second modules for detachably connecting an open end of one module to an open end of the other module and wherein said conveying surface is common to both modules and said ports of each said manifold are positioned to admit gas both above and below said conveying surface and are adapted such that gas will be admitted predominantly below said conveying surface in said first module and predominately above said conveying surface in said second module.

Claim 12

An oven comprising first and second modules each comprising: a. a body of low thermal mass forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, b. first manifolds located between said side walls, c. ports in said manifolds for admitting gas to the zone of the tunnel between the manifolds, d. heating means for gas admitted into said zone, e. first drive means for driving gas past said heating means and through said manifolds, f. outlet means positioned opposite said ports to permit flow of gas across said zone and from said tunnel, g. second drive means for drawing gas from said zone through said outlet means and for driving that gas to the inpUt of said first drive means and to exhaust means, and h. conveying means for conveying articles through said tunnel, said conveying means including a flexible endless conveying surface and supporting means therefor provided on each manifold, said oven also including means provided on said first and second modules for detachably connecting an open end of one module to an open end of the other module and wherein said conveying surface is common to both modules and said ports of each said manifold are positioned to admit gas both above and below said conveying surface and are adapted such that gas will be admitted predominantly below said conveying surface in said first module and predominately above said conveying surface in said second module.

Claim 13

An oven as claimed in claim 10 wherein each module comprises control means for controlling the proportion of gas fed to said respective exhaust means and to the input of said respective first drive means.

Claim 14

An oven as claimed in claim 11 wherein each control means includes a water vapour detector in said respective zone and connected to control valve means between said respective first and second drive means.

Claim 15

An oven as claimed in claim 12 comprising a third module comprising: a. a low thermal mass body forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, b. conveying means for conveying articles through said tunnel, said conveying means comprising a flexible endless conveying surface and supporting means therefor, and c. a radiant heater situated above said conveying surface, wherein said conveying surface is common to said first, second and third modules and means are provided on said second and third modules for detachably connecting an open end of said third module to that open end of said second module remote from said first module.

Claim 16

Apparatus as claimed in claim 13 wherein said radiant heater comprises a plurality of heater strips, each strip comprising an electrical heating element of electrically resistive material and an electrically insulating body in which said heating element is embedded, said body incorporating fibrous alumino-silicate material.

Claim 17

An oven as claimed in claim 1 wherein said conveying surface is a belt of polytetrafluoroethylene coated woven material and locating means are provided on the lateral margins of the belt for locating the belt relative to said supporting means against transverse movement.

Claim 18

Apparatus as claimed in claim 15 wherein said locating means engage in said supporting means and are detachably provided on the lateral margins of said belt.

Claim 19

Apparatus as claimed in claim 1 wherein said body of said first module comprises panels of a light weight metal honeycomb structure, the cells of which extend between metal skins, the panel being covered on the inner surfaces therein with heat insulation material.

Claim 20

An oven as claimed in claim 10 wherein said body of each of said first and second modules comprises panels of a light weight metal honeycomb structure, the cells of which extend between metal skins, the panels being covered on the inner surfaces thereof with heat insulation material.

Claim 21

An oven as claimed in claim 13 wherein said body of said third module comprises panels of a lightweight metal honeycomb structure, the cells of which extend between metal skins, the panels being covered on the inner surfaces thereof with heat insulation material.

Claim 22

An oven as claimed in claim 13 comprising a plurality of at least one of the first, second and third mdoules.

Claim 23

An oven comprising a first module comprising: a. a body of low thermal mass forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, b. first manifolds located between said side walls, c. ports in said manifolds for admitting gas to the zone of the tunnel between the manifolds, d. heating means for gas admitted into said zone, e. first drive means for driving gas past sAid heating means and through said manifolds, f. outlet means positioned opposite said ports to permit flow of gas across said zone and from said tunnel, g. second drive means for drawing gas from said zone through said outlet means and for driving that gas to the input of said first drive means and to exhaust means, and h. conveying means for conveying articles through said tunnel, said conveying means including a flexible endless conveying surface and supporting means therefor provided on each manifold, and a second module comprising: i. a low thermal mass body forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, ii. conveying means for conveying articles through said tunnel, said conveying surface and supporting means therefor, and iii. a radiant heater situated above said conveying surface, wherein said conveying surface is common to said first and second modules and means are provided on said first and second modules for detachably connecting an open end of one module to an open end of the other module.

Claim 24

An oven comprising a first module comprising: a. a body of low thermal mass forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, b. first manifolds located between said side walls, c. ports in said manifolds for admitting gas to the zone of the tunnel between the manifolds, d. heating means for gas admitted into said zone, e. first drive means for driving gas past sAid heating means and through said manifolds, f. outlet means positioned opposite said ports to permit flow of gas across said zone and from said tunnel, g. second drive means for drawing gas from said zone through said outlet means and for driving that gas to the input of said first drive means and to exhaust means, and h. conveying means for conveying articles through said tunnel, said conveying means including a flexible endless conveying surface and supporting means therefor provided on each manifold, and a second module comprising: i. a low thermal mass body forming a top wall, a bottom wall and side walls defining a tunnel open at both ends, ii. conveying means for conveying articles through said tunnel, said conveying surface and supporting means therefor, and iii. a radiant heater situated above said conveying surface, wherein said conveying surface is common to said first and second modules and means are provided on said first and second modules for detachably connecting an open end of one module to an open end of the other module.

Claim 25

Apparatus as claimed in claim 1 wherein said temperative varying means is a heating means.

Claim 26

Apparatus as claimed in claim 4 wherein said temperative varying means is a heating means.

Claim 27

Apparatus as claimed in claim 7 wherein said temperative varying means is a heating means.

Claim 28

Apparatus as claimed in claim 9 wherein said temperative varying means is a heating means.