Fluid pumps with increased pumping efficiency

Abstract

A fluid pump includes a piston disposed within a compartment and defining therewith a fluid-charging chamber on one side of the piston and a fluid-pumping chamber on the opposite side of the piston. The piston is formed with an opening therethrough establishing communication between the chambers. A one-way valve carried by the piston is effective to close the opening through the piston during the forward-pumping strokes and to open the opening during the return strokes. Further valve means are provided effective: to open the inlet with respect to the fluid-charging chamber during the forward-pumping strokes, to close the inlet with respect to the fluid-charging chamber during the return strokes, to open the outlet with respect to the fluid-pumping chamber during the forward-pumping strokes, and to close the outlet with respect to the fluid-pumping chamber during the return strokes. The arrangement is such that during the return strokes, pressurized fluid from the fluid-charging chamber flows through the opening through the piston into the fluid-pumping chamber to thereby supercharge the fluid-pumping chamber before the start of the forward-pumping strokes.

What is claimed is:  
     
         1 . A fluid pump, comprising: 
 a housing having an inlet, an outlet, a passageway connecting said inlet to said outlet, and a compartment in said passageway;    a piston disposed within said compartment and defining therewith a fluid-charging chamber on one side of the piston and a fluid-pumping chamber on the opposite side of the piston; said piston being reciprocatable in said compartment through forward-pumping strokes and return strokes;    said piston being formed with an opening therethrough establishing communication between said chambers, and including a one-way valve effective to close said opening during the forward-pumping strokes and to open said opening during the return strokes;    and further valve means effective: to open said inlet with respect to said fluid-charging chamber during said forward-pumping strokes, to close said inlet with respect to said fluid-charging chamber during said return strokes, to open said outlet with respect to said fluid-pumping chamber during said forward-pumping strokes, and to close said outlet with respect to said fluid-pumping chamber during said return strokes; such that during said return strokes, pressurized fluid from said fluid-charging chamber flows through said opening through the piston into said fluid-pumping chamber to thereby supercharge said fluid-pumping chamber before the start of said forward-pumping strokes.    
     
     
         2 . The fluid pump according to  claim 1 , wherein said compartment is of cylindrical configuration.  
     
     
         3 . The fluid pump according to  claim 1 , wherein said piston further includes a cylindrical section of smaller diameter than said piston and located in said fluid-pumping chamber such that the effective volume of said fluid-pumping chamber is less than that of said fluid-charging chamber.  
     
     
         4 . The fluid pump according to  claim 1 , wherein said piston includes a plurality of said opening therethrough, and a said one-way valve for each of said openings.  
     
     
         5 . The fluid pump according to  claim 1 , wherein said further valve means comprises: 
 a second one-way valve effective to open said inlet with respect to said fluid-charging chamber during said forward-pumping strokes, and to close said inlet with respect to said fluid-charging chamber during said return strokes;    and a third one-way valve effective to open said outlet with respect to said fluid-pumping chamber during said forward-pumping strokes, and to close said outlet with respect to said fluid-pumping chamber during said return strokes.    
     
     
         6 . The fluid pump according to  claim 5 , wherein said second one-way valve and said third one-way valve are carried by said housing.  
     
     
         7 . The fluid pump according to  claim 6 , wherein said housing includes a plurality of said second one-way valves and a plurality of said third one-way valves.  
     
     
         8 . The fluid pump according to  claim 1 , wherein said housing outlet is formed axially through a transverse wall of said housing.  
     
     
         9 . The fluid pump according to  claim 1 , wherein said housing outlet is formed radially through a circumferential wall of said housing.  
     
     
         10 . The fluid pump according to  claim 1 , wherein said housing further includes an inlet chamber communicating with said fluid-charging chamber for damping the pressure fluctuations and sounds of the inletted fluid, and/or an outlet chamber communicating with said fluid-pumping chamber for damping the pressure fluctuations and sounds of the outletted fluid.  
     
     
         11 . The fluid pump according to  claim 1 , wherein said pump is a two-stage pump, including a first stage at one end of said housing and constructed as defined, and a second stage at the opposite end of the housing and of the same construction as said first stage; the fluid-pumping chamber of said first stage communicating with the fluid-charging chamber of said second stage such that, during each forward stroke of the pump, fluid from the fluid-pumping chamber of the first stage is pumped into the fluid-charging chamber of the second stage.  
     
     
         12 . The fluid pump according to  claim 1 , wherein said housing further includes a linear drive for reciprocating said piston through said forward-pumping and return strokes.  
     
     
         13 . The fluid pump according to  claim 11 , wherein said drive is an electromagnetic linear drive coupled to said piston to reciprocate it through linear forward-pumping and return strokes.  
     
     
         14 . The fluid pump according to  claim 13 , wherein said electromagnetic linear drive comprises: 
 a core of magnetically permeable material having a longitudinal axis, a central section coaxial with said longitudinal axis, an outer section spaced outwardly from said central section, and a bridging side section bridging the outer and central sections at one side of the core, the opposite side of the core being open;    a coil in the space between said central and outer sections of said core and spaced inwardly of the open side of the core such that the coil is completely recessed within the core, and the outer and central sections of the core define an extension extending laterally past the recessed coil;    a movable armature of magnetically permeable material facing and aligned with said extension in the core, said armature being movable towards and away from said coil and being formed with a central recess;    and a pair of springs on the opposite ends of said core and coaxial with the longitudinal axis of the core, said pair of spring mounting said armature for straight-line reciprocatory movements parallel to said longitudinal axis of the core;    said armature and its recess being configured and located such that during the movement of the armature towards and away from the coil: 
 (a) the recess receives said central section of the core;  
 (b) the outer surface of the armature defines a first working gap with the inner surface of the core outer section at said extension;  
 (c) and the inner surface of the armature at said recess defines a second working gap with the outer surface of the core central section at said extension.  
   
     
     
         15 . A fluid pump, comprising: 
 a housing having an inlet, an outlet, a passageway connecting said inlet to said outlet, and a compartment in said passageway;    a piston disposed within said compartment and defining therewith a fluid-charging chamber on one side of the piston and a fluid-pumping chamber on the opposite side of the piston; said piston being reciprocatable in said compartment through forward-pumping strokes and return strokes;    said piston being formed with an opening therethrough establishing communication between said chambers;    a drive for reciprocating said piston through said forward and return strokes;    a first one-way valve, carried by said piston, effective to close said opening through the piston during said forward-pumping strokes and to open said opening during said return strokes;    a second one-way valve effective to open said inlet with respect to said fluid-charging chamber during said forward-pumping strokes, and to close said inlet with respect to said fluid-charging chamber during said return strokes;    and a third one-way valve effective to open said outlet with respect to said fluid-pumping chamber during said forward-pumping strokes, and to close said outlet with respect to said fluid-pumping chamber during said return strokes;    the arrangement being such that, during said return strokes, pressurized fluid from said fluid-charging chamber flows through said opening through the piston into said fluid-pumping chamber to thereby supercharge fluid-pumping chamber before the start of said forward-pumping strokes.    
     
     
         16 . The fluid pump according to  claim 15 , wherein said housing further includes a linear drive for reciprocating said piston through said forward-pumping and return strokes.  
     
     
         17 . The fluid pump according to  claim 15 , wherein said housing outlet is formed axially through a transverse wall of said housing.  
     
     
         18 . The fluid pump according to  claim 15 , wherein said housing outlet is formed radially through a circumferential wall of said housing.  
     
     
         19 . The fluid pump according to  claim 15 , wherein said piston further includes a cylindrical section of smaller diameter than said piston and located in said fluid-pumping chamber such that the effective volume of said fluid-pumping chamber is less than that of said fluid-charging chamber.  
     
     
         20 . The fluid pump according to  claim 15 , wherein said pump is a two-stage pump, including a first stage at one end of said housing and constructed as defined, and a second stage at the opposite end of the housing and of the same construction as said first stage; the fluid-pumping chamber of said first stage communicating with the fluid-charging chamber of said second stage such that, during each forward stroke of the pump, fluid from the fluid-pumping chamber of the first stage is pumped into the fluid-charging chamber of the second stage.