Sheet-type regenerative heat exchanger and manufacturing method thereof, and regenerator and refrigerator using the same

Abstract

A high-performance, long-lasting, and inexpensive sheet-type regenerative heat exchanger suitable for a refrigerator for achieving low temperature cooling, and a regenerator or a refrigerator using the same are provided. The sheet-type regenerative heat exchanger includes a very thin sheet-like holding base, and at least one layer of numerous granules such as balls, chips, and fine particles having a relatively uniform particle size bonded to one or both surfaces of the sheet-like holding base. An alignment substrate may be used for bonding the granules in alignment to the sheet-like holding base. Alternatively, numerous minute holes may be drilled in the sheet-like holding base at intermediate positions between adjacent small apertures formed in the alignment substrate, for enhancing gas flow efficiency.

What is claimed is:  
     
         1 . A sheet-type regenerative heat exchanger, comprising: 
 a thin, elongated sheet-like holding base coated with an adhesive on one surface or both surfaces thereof;    numerous granules such as balls, chips and fine particles having a relatively uniform particle size which are made of one or a plurality of heat storing materials, and bonded continuously on one surface or both surfaces of the sheet-like holding base along its length over a range of predetermined width to form at east one layer.    
     
     
         2 . A sheet-type regenerative heat exchanger, obtained through the steps of: 
 providing an alignment substrate formed with numerous, precisely aligned small apertures which are constituted by through holes or dimples;    placing numerous granules such as balls, chips and fine particles having a relatively uniform particle diameter or size, which are made of one or a plurality of heat storing materials, into said small apertures such that each piece of the balls, chips, or fine particles is received in each one of the small apertures in the alignment substrate; and    bonding said balls, chips, or fine particles onto one or both surfaces of a very thin, elongated sheet-like holding base such as a cloth or film having an adhesive layer on one or both surfaces thereof, over a predetermined widthwise range along the length thereof.    
     
     
         3 . A sheet-type regenerative heat exchanger, obtained through the steps of: 
 providing an alignment substrate formed with numerous, precisely aligned small apertures;    placing numerous granules such as balls, chips and fine particles having a relatively uniform particle diameter or size, which are made of one or a plurality of heat storing materials, such that each piece of the balls, chips, or fine particles is received in each one of the small apertures in the alignment substrate; and    bonding said balls, chips, or fine particles onto one or both surfaces of a very thin, elongated sheet-like holding base such as a cloth or film having an adhesive layer on one or both surfaces thereof, over a predetermined widthwise range along the length thereof; wherein during the bonding step, numerous minute holes having a diameter equal to or less than a half of the particle diameter or size of the balls, chips, or fine particles are drilled in the sheet-like holding base at intermediate positions between adjacent small apertures formed in the alignment substrate by minute hole drilling means such as a laser electron beam.    
     
     
         4 . The sheet-type regenerative heat exchanger according to  claim 3 , wherein the diameter of said numerous minute holes formed in said alignment substrate is 80% or lower of the particle diameter or size of said granules such as balls, chips, and fine particles.  
     
     
         5 . The sheet-type regenerative heat exchanger according to any one of  claims 1  to  4 , wherein said granules are made of one or more of Cu alloy, stainless steel, Fe—Ni alloy and Pb—Zn alloy, with or without plating of Pb or an alloy thereof, and have a particle size of 40 to 800 μm.  
     
     
         6 . The sheet-type regenerative heat exchanger according to any one of  claims 1  to  4 , wherein said granules are made of one or more of an alloy, which has high specific heat at low temperatures, such as Nd, DyNi 2 , Er 3 Ni, Er 6 Ni 2 Sn, ErNi 0.9 Co 0.1 , Gd 5 Al 2 , HoCu 2 , GdAlO 3 , and Nd 2 Fe 17 Al, a magnetic oxide, and a magnetic substance and have a particle size of 40 to 800 μm.  
     
     
         7 . The sheet-type regenerative heat exchanger according to any one of  claims 1  to  6 , wherein said holding base is a woven cloth having a thickness of 10 to 100 μm, made from a fiber selected from the group consisting of para-aramid fiber, high tenacity polyarylate fiber, PBO fiber, polyethylene fiber, Teflon™ fiber, polyester fiber, Kevlar™ fiber, natural fiber, and glass fiber, and has so small a mesh that said granules do not pass therethrough.  
     
     
         8 . The sheet-type regenerative heat exchanger according to any one of  claims 1  to  6 , wherein said holding base is formed of film made of polypropylene, polyimide, capton, or the like, and has a thickness of 10 to 100 μm.  
     
     
         9 . The sheet-type regenerative heat exchanger according to any one of  claims 1  to  6 , wherein said holding base is formed of either paper or non-woven cloth made of either artificial fiber or natural substance as a base material, and has a thickness of 10 to 100 μm.  
     
     
         10 . A regenerator including the sheet-type regenerative heat exchanger according to any one of  claims 1  to  9  wound in multiple layers around a core which is constituted by either one piece or divided pieces, formed in either a columnar shape or other shapes, and made of a material having an extremely low expansion coefficient and thermal conductivity.  
     
     
         11 . The regenerator according to  claim 10 , wherein said core formed in a columnar shape or other shapes is a pulse tube for a pulse-tube refrigerator.  
     
     
         12 . A method for manufacturing a sheet-type regenerative heat exchanger including: 
 a first step of randomly arranging, within a frame on a flat plate having extremely high flatness, at least one layer of numerous granules such as balls, chips, and fine particles which are made of a material having high specific heat per unit volume in a range of temperatures employed and have a relatively uniform particle size;    a second step of putting a sheet-like holding base coated with an adhesive, upon the granules; and    a third step of moving a roller under pressure on said sheet-like holding base to bond at least one layer of said granules onto said sheet-like holding base so that the granules sink into the adhesive by a depth equal to or lower than 30% of the height of said granules.    
     
     
         13 . A method for manufacturing a sheet-type regenerative heat exchanger including: 
 a first step of arranging numerous granules such as balls, chips, and fine particles which are made of one or a plurality of heat storing materials and have a relatively uniform particle diameter or size, onto an alignment substrate formed with numerous, precisely aligned small apertures, such that each piece of the balls, chips, or fine particles is received in each one of the small apertures;    a second step of putting a very thin sheet-like holding base such as cloth or film coated with an adhesive thereon; and    a third step of moving a roller under pressure on said sheet-like holding base to bond said granules onto said sheet-like holding base with a compressive strain inclined to the adhesive equal to or lower than 30% of the height of said granules.    
     
     
         14 . A method for manufacturing a sheet-type regenerative heat exchanger including: 
 a first step of arranging numerous granules such as balls, chips and fine particles which are made of one or a plurality of heat storing materials and have a relatively uniform particle diameter or size, onto an alignment substrate formed with numerous, precisely aligned small apertures such that each piece of the balls, chips, or fine particles is received in each one of the small apertures;    a second step of putting a very thin sheet-like holding base such as a cloth or film coated with an adhesive thereon;    a third step of moving a roller under pressure on said sheet-like holding base to bond said granules onto said sheet-like holding base with a compressive strain inclined to the adhesive equal to or lower than 30% of the height of said granules; and    a fourth step of drilling numerous small holes having a diameter equal to or less than a half of the particle diameter or size of the granules such as balls, chips and fine particles in the sheet-like holding base at intermediate positions between adjacent small apertures formed in the alignment substrate by small hole drilling means such as a laser electron beam.    
     
     
         15 . A refrigerator using the sheet-type regenerative heat exchanger according to any one of  claims 1  to  9  for a regenerator.