Pump

Abstract

To provide a pump capable of discharging gas bubbles and thus maintaining a discharging ability, even when the gas bubbles stay inside a pump chamber, a pump includes a primary pump chamber whose volume can be varied by driving a diaphragm, an inlet passage to allow a working fluid to flow into the primary pump chamber, an outlet passage to allow the working fluid to flow out of the primary pump chamber, and check valves to open and close at least the inlet passage. A resultant inertance value of the inlet passage is set to be smaller than a resultant inertance value of the outlet passage. A bubble discharging device to discharge gas bubbles remained in the primary pump chamber is further provided. As a result, it is possible to provide a pump capable of discharging gas bubbles with the bubble discharging device and thus maintain a discharging ability, even when the gas bubbles stay in the primary pump chamber.

1 . A pump, comprising: 
 a pump chamber whose volume can be varied by driving a piston or a movable wall;    an inlet passage to allow a working fluid to flow into the pump chamber;    an outlet passage to allow the working fluid to flow out of the pump chamber,    a fluid resistance element to open and close at least the inlet passage, a resultant inertance value of the inlet passage being set to be smaller than a resultant inertance value of the outlet passage; and    a bubble discharging device to discharge gas bubbles remaining in the pump chamber.    
   
   
       2 . The pump according to  claim 1 , 
 the pump chamber including a primary pump chamber which communicates with the outlet passage and whose volume can be varied by driving a piston or a movable wall, and a secondary pump chamber which communicates with the inlet passage and functions as the bubble discharging device and whose volume can be varied by driving a movable wall.    
   
   
       3 . The pump according to  claim 2 , further comprising: 
 a primary pump chamber inlet passage to allow the working fluid to flow into the primary pump chamber;    a primary pump chamber outlet passage to allow the working fluid to flow out of the primary pump chamber;    a secondary pump chamber inlet passage to allow the working fluid to flow into the secondary pump chamber; and    a secondary pump chamber outlet passage to allow the working fluid to flow out of the secondary pump chamber, the primary pump chamber inlet passage also functioning as the secondary pump chamber outlet passage.    
   
   
       4 . The pump according to  claim 3 , further comprising: 
 a fluid resistance element to open and close the primary pump chamber inlet passage;    a fluid resistance element to open and close the secondary pump chamber inlet passage; and    a fluid resistance element to open and close the secondary pump chamber outlet passage,    the fluid resistance element to open and close the primary pump chamber inlet passage also functioning as the fluid resistance element to open and close the secondary pump chamber outlet passage.    
   
   
       5 . The pump according to  claim 2 , 
 the movable wall provided in the secondary pump chamber being a diaphragm in which a piezoelectric element is attached to at least one surface thereof, and the secondary pump chamber and the diaphragm including a unimorph pump or a bimorph pump.    
   
   
       6 . The pump according to  claim 2 , further comprising: 
 a driving switch control unit to switch the driving between the secondary pump chamber and the primary pump chamber.    
   
   
       7 . The pump according to  claim 5 , 
 a driving electrode and a detecting electrode are formed in the piezoelectric element.    
   
   
       8 . The pump according to  claim 2 , further comprising: 
 a pressure detecting section to detect an inside pressure of the primary pump chamber.    
   
   
       9 . The pump according to  claim 1 , further comprising: 
 a pressurizing mechanism serving as the bubble discharging device to raise and maintain the pressure of the working fluid existing in the pump chamber.    
   
   
       10 . The pump according to  claim 9 , 
 the pressurizing mechanism, comprises:    a variable-volume chamber and a flow passage to allow the variable-volume chamber and the outlet passage to communicate with each other.    
   
   
       11 . The pump according to  claim 10 , 
 the variable-volume chamber being formed of an elastic member.    
   
   
       12 . The pump according to  claim 10 , 
 the pressurizing mechanism, further comprises:    a volume varying mechanism to apply a pressure to vary the volume of the variable-volume chamber.    
   
   
       13 . The pump according to  claim 9 , 
 the pressurizing mechanism, comprises:    a passage switching section to switch between a first mode where the working fluid flowing out of the pump chamber is introduced into the variable-volume chamber, and a second mode where the working fluid flowing out of the pump chamber is isolated from the variable-volume chamber.    
   
   
       14 . The pump according to  claim 10 , further comprising: 
 a pressure detecting section to detect an inside pressure of the variable-volume chamber.    
   
   
       15 . The pump according to  claim 9 , 
 a pressure detecting device being provided in the pump chamber.    
   
   
       16 . The pump according to  claim 12 , 
 the inside pressure of the variable-volume chamber, which is pressurized by the pressurizing mechanism, ranging from about one atmosphere to about five atmospheres in a gauge pressure.    
   
   
       17 . The pump according to  claim 9 , 
 the pressurizing mechanism, comprises:    a variable-volume chamber;    a flow passage communicating with the outlet passage; and    an opening and closing member to open and close the flow passage, and    the pressurizing mechanism being detachable from the outlet passage, and the variable-volume chamber and the outlet passage being allowed to communicate with each other by fitting the pressurizing mechanism into the outlet passage.    
   
   
       18 . The pump according to  claim 1 , 
 a heating section serving as the bubble discharging device being provided in the pump chamber.    
   
   
       19 . The pump according to  claim 18 , 
 the heating section being received inside the wall of the pump chamber, or being arranged in a comer portion of the pump chamber.    
   
   
       20 . The pump according to  claim 18 , 
 a plurality of the heating sections being provided.    
   
   
       21 . The pump according to  claim 18 , further comprising: 
 a pressure detecting section to detect an inner pressure of the pump chamber.    
   
   
       22 . The pump according to  claim 18 , 
 when the piston or the movable wall is being driven, a heating signal being input to the heating section.    
   
   
       23 . The pump according to  claim 18 , 
 a pulse-shaped heating signal being input to the heating section, and the piston or the movable wall being driven in synchronism with the heating signal.    
   
   
       24 . The pump according to  claim 19 , 
 the heating section heating the working fluid to change the phase of the working fluid in contact with the heating section.