Pump and method of manufacturing same

Abstract

A compact pump has a pump chamber, inlet and outlet channels communicating with the pump chamber, and a pair of check valve units between the pump chamber and the inlet and outlet channels. Each check valve unit has a thin film check valve membrane, and a check valve body with a channel opened and closed by the check valve membrane due to a pressure difference.

What is claimed is:  
     
         1 . A piezoelectric pump for sucking fluid to a pump chamber and discharging fluid from the pump chamber by changing a volume of the pump chamber by action of a piezoelectric actuator, said piezoelectric pump comprising: 
 a casing having inlet and outlet flow channels both communicating with the pump chamber;    first and second check valve units each having a thin-film check valve membrane and a check valve body having a channel opened and closed by the check valve membrane; and    the first and second check valve units being disposed between the pump chamber and the inlet and outlet flow channels, respectively.    
     
     
         2 . The piezoelectric pump according to  claim 1 , further comprising a diaphragm comprising a piezoelectric actuator and a thin metal plate joined together, wherein the diaphragm is mounted to the casing to form the pump chamber between the diaphragm and the casing.  
     
     
         3 . The piezoelectric pump according to  claim 1 , wherein the first and second check valve units are identically configured and installed to the casing in inverse positions.  
     
     
         4 . The piezoelectric pump according to  claim 1 , wherein the first and second check valve units are installed to the casing from a side opposite the diaphragm side.  
     
     
         5 . The piezoelectric pump according to  claim 1 , wherein the casing comprises a first casing part to which the diaphragm is disposed and a second casing part that is separate from the first casing part and to which the first and second check valve units are installed.  
     
     
         6 . The piezoelectric pump according to  claim 5 , wherein a fitting structure is used at least between the casing and the first and second check valve units or between the first and second casing parts, and the fitting structure is an interference fitting assembled by press fitting.  
     
     
         7 . The piezoelectric pump according to  claim 5 , wherein a fitting structure is used at least between the casing and the first and second check valve units or between the first and second casing parts, and the fitting structure is a transition fitting or clearance fitting completed with adhesion or welding.  
     
     
         8 . The piezoelectric pump according to  claim 5 , wherein a fitting structure is used at least between the casing and the first and second check valve units or between the first and second casing parts, and the fitting structure has screw threads formed therein for screw fitting.  
     
     
         9 . The piezoelectric pump according to  claim 1 , wherein the check valve membrane is positioned to cover the channel in the check valve body, and the check valve membrane is joined to the check valve body.  
     
     
         10 . The piezoelectric pump according to  claim 9 , wherein the check valve membrane has at least one vent formed therein and is disposed so as to cover the channel in the check valve body, and the check valve membrane around the vent is joined to the check valve body.  
     
     
         11 . The piezoelectric pump according to  claim 10 , wherein the check valve membrane has two vents formed at positions on opposite sides of the channel.  
     
     
         12 . The piezoelectric pump according to  claim 10 , wherein the check valve membrane has a single vent parallel to a tangent to the outside circumference of the channel, the single vent being formed at a position removed from the channel.  
     
     
         13 . The piezoelectric pump according to  claim 10 , wherein the check valve membrane has a plurality of vents each parallel to a tangent to an outside circumference of the channel, the plurality of vents being formed circumferentially to the channel at positions removed therefrom.  
     
     
         14 . The piezoelectric pump according to  claim 10 , wherein the vent in the check valve membrane is shaped into a continuous curve.  
     
     
         15 . The piezoelectric pump according to  claim 9 , wherein the check valve membrane is disposed so as to cover the channel, and two sides thereof on opposite sides of the channel are joined to the check valve body.  
     
     
         16 . The piezoelectric pump according to  claim 9 , wherein the check valve membrane has one openable side and is disposed so as to cover the channel, the check valve membrane being joined to the check valve body surrounding the channel except on the one openable side.  
     
     
         17 . The piezoelectric pump according to  claim 9 , wherein the check valve membrane is disposed so as to cover the channel and joined in spots around the circumference of the channel to the check valve body, and intervals between the joined spots are vents.  
     
     
         18 . The piezoelectric pump according to  claim 17 , wherein the check valve membrane is shaped into a polygon and placed so as to cover the channel, and each corner of the polygon is joined to the check valve body.  
     
     
         19 . The piezoelectric pump according to  claim 9 , wherein the check valve membrane has a flap formed by removing a part of a thin film, and the check valve membrane is joined to the check valve body around the perimeter of the flap.  
     
     
         20 . The piezoelectric pump according to  claim 19 , wherein the channel opened and closed by the flap is formed from a plurality of openings separated a specific interval, and a support part for supporting the flap is formed in a center of the plurality of openings.  
     
     
         21 . The piezoelectric pump according to  claim 9 , wherein the check valve membrane is formed into a rectangular strip and is joined on only one side thereof perpendicular to a long side thereof to the check valve body.  
     
     
         22 . The piezoelectric pump according to  claim 9 , wherein the check valve body is formed with first and second spacers having a fitting structure, and the check valve membrane is inserted between and joined to the first and second spacers.  
     
     
         23 . The piezoelectric pump according to  claim 22 , wherein the first and second spacers are bonded.  
     
     
         24 . The piezoelectric pump according to  claim 9 , wherein the check valve membrane and the check valve body are welded together.  
     
     
         25 . The piezoelectric pump according to  claim 9 , wherein the check valve body is formed with first and second spacers, the check valve membrane is disposed between the first and second spacers, and the first and second spacers and the check valve membrane are welded together.  
     
     
         26 . A method of manufacturing a pump, comprising: 
 forming a vent in a check valve membrane made of a thin film;    forming a channel in a check valve body;    placing the check valve membrane so as to cover the channel;    joining the check valve membrane around the vent to the check valve body to form a check valve unit in which the channel is opened and closed by the check valve membrane due to a pressure differential; and    installing the check valve unit in a casing.    
     
     
         27 . The method according to  claim 26 , wherein the vent in the thin film is formed with an excimer laser.  
     
     
         28 . A method of manufacturing a pump, comprising: 
 forming a channel in a check valve body;    placing a check valve membrane so as to cover the channel;    joining the check valve membrane to the check valve body around the channel;    forming a vent in the check valve membrane at a position between a joint and the channel to form a check valve unit in which the channel is opened and closed by the check valve membrane due to a pressure differential; and    installing the check valve unit in a casing.    
     
     
         29 . The method according to  claim 28 , wherein the vent in the thin film is formed with an excimer laser.  
     
     
         30 . A method of manufacturing a pump, comprising: 
 forming a channel in a check valve body;    placing a check valve membrane so as to cover the channel;    pressing the check valve membrane to the check valve body with a glass plate while a laser beam is emitted to weld the check valve membrane to the check valve body to form a check valve unit in which the channel is opened and closed by the check valve membrane due to a pressure differential; and    installing the check valve unit in a casing.    
     
     
         31 . The method according to claim  30 , wherein an iris having an aperture is used for laser welding to simultaneously weld specific parts of the check valve membrane to the check valve body.