Method for making welded hollow plastic plate heat exchangers

Claim 1

A method for making a welded plastic hollow plate heat exchanger comprising the steps of: (a) stacking two or more hollow plastic plates open at two opposite edges and closed at the other two edges alternately with hollow spacer strips running parallel to the open edges of the hollow plastic plates with at least two spacer strips, each one adjacent to the open edges of the hollow plastic plate, said hollow spacer strips having at least one septum running the full length of the strip, (b) holding the array of plates and spacers in place with a mechanical or adhesive means or both, (c) providing melt sealing means, such as a taut hot wire, (d) heating the melt sealing means to a temperature substantially above the melting point of the plastic forming the array, (e) passing the hot sealing means in a place parallel to the open edge of the sheet and bisecting the spacer strip thereby cutting and melting together the skin on the bottom of the hollow plate to the skin of the top of the adjacent spacer and the skin of the bottom of the spacer to the skin on the top of the hollow plate immediately below the spacer until the entire array is melted together, (f) removing the thin sheet formed from the cut-off edges and spacer to prevent it from rewelding to the cut-off face, (g) allowing the array to cool to a temperature below the melting point of the plastic to form a welded together face, (h) repeating the step (d), (e), (f), and (g) on the opposite side face of the array to form a welded monolithic hollow plastic plate heat exchanger.

Claim 2

A method for making a welded plastic hollow plate heat exchanger comprising the steps of: (a) stacking two or more hollow plastic plates open at two opposite edges and closed at the other two edges alternately with hollow spacer strips running parallel to the open edges of the hollow plastic plates with at least two spacer strips, each one adjacent to the open edges of the hollow plastic plate, said hollow spacer strips having at least one septum running the full length of the strip, (b) holding the array of plates and spacers in place with a mechanical or adhesive means or both, (c) providing melt sealing means, such as a taut hot wire, (d) heating the melt sealing means to a temperature substantially above the melting point of the plastic forming the array, (e) passing the hot sealing means in a place parallel to the open edge of the sheet and bisecting the spacer strip thereby cutting and melting together the skin on the bottom of the hollow plate to the skin of the top of the adjacent spacer and the skin of the bottom of the spacer to the skin on the top of the hollow plate immediately below the spacer until the entire array is melted together, (f) removing the thin sheet formed from the cut-off edges and spacer to prevent it from rewelding to the cut-off face, (g) allowing the array to cool to a temperature below the melting point of the plastic to form a welded together face, (h) repeating the step (d), (e), (f), and (g) on the opposite side face of the array to form a welded monolithic hollow plastic plate heat exchanger.