Pumping apparatus having a piston with a diamond-like carbon coating

Abstract

A pumping apparatus is provided, which comprises a piston ( 1 ) for reciprocation in a pump working chamber ( 3 ), a valve, coupled to said pump working chamber ( 3 ) in order to permit liquid flow only unidirectional and a drive unit for reciprocating said piston ( 1 ). The liquid in said pump working chamber ( 3 ) is compressed to a high pressure, at which compressibility of the liquid becomes noticeable. The piston ( 1 ) is at least partially coated with a diamond-like carbon coating ( 2 ), adapted to provide a reduced abrasion of said piston ( 1 ).

1 . A high performance liquid chromatography pumping apparatus adapted to perform liquid pumping in a high performance liquid chromatography device, the pumping apparatus comprising: 
 a first piston for reciprocation in a first pump working chamber,    a valve, coupled to said first pump working chamber, to permit only unidirectional liquid, and    a drive unit for reciprocating said first piston,    wherein:    the liquid in said first pump working chamber is compressed to a high pressure, at which compressibility of the liquid becomes noticeable, and    said first piston is at least partially coated with a diamond-like carbon coating, adapted to provide a reduced abrasion of the first piston.    
   
   
       2 . The pumping apparatus of  claim 1 , wherein the first pump working chamber has an inlet port and an outlet port.  
   
   
       3 . The pumping apparatus of  claim 1 , wherein the valve is an inlet valve.  
   
   
       4 . The pumping apparatus of  claim 1 , wherein the drive unit comprises a piston holder to which the first piston is mounted.  
   
   
       5 . The pumping apparatus of  claim 1 , comprising: 
 a second piston, wherein the first and second pistons are arranged in one of a dual serial or dual parallel mode, adapted to provide a continuous pumping by performing pump cycles,    
   
   
       6 . The pumping apparatus of  claim 1 , wherein the first piston is made of one of the following: sapphire, ceramics and metals.  
   
   
       7 . The pumping apparatus of  claim 6 , wherein the metal is steel.  
   
   
       8 . The pumping apparatus of  claim 1 , wherein the diamond-like carbon coating has a coating thickness ranging from 0.1 to 10 micrometers.  
   
   
       9 . (canceled)  
   
   
       10 . The pumping apparatus according to  claim 1 , wherein said high pressure ranges from 200 to 2000 bar.  
   
   
       11 . The pumping apparatus according to  claim 1 , wherein the liquid is pumped at a selectable flow rate.  
   
   
       12 . (canceled)  
   
   
       13 . The pumping apparatus of  claim 1 , comprising a second piston for reciprocation in a second pump working chamber having a second inlet port and a second outlet port, wherein the first pump working chamber includes a first inlet port and a first outlet port.  
   
   
       14 . The pumping apparatus of  claim 13 , comprising a conduit coupling between the first outlet port of the first pump working chamber and the second inlet port of the second pump working chamber to provide a liquid communication from the first pump working chamber into the second pump working chamber.  
   
   
       15 . The pumping apparatus of  claim 13 , comprising a first inlet valve connected to the first inlet port of the first pump working chamber to permit only unidirectional liquid flow into said first pump working chamber.  
   
   
       16 . The pumping apparatus of  claim 13 , comprising a first outlet valve connected to the first outlet port of the first pump working chamber to permit only unidirectional liquid flow into said second pump working chamber.  
   
   
       17 . The pumping apparatus of  claim 13 , wherein the drive unit is operable to reciprocate the first and the second piston, 
 wherein: 
 the liquid in the first pump working chamber is compressed to said high pressure before delivery of the compressed liquid into the second pump working chamber, and  
 at least one of said first and second pistons that are reciprocated into said first and second working chambers, respectively, is at least partially coated with a diamond-like carbon coating, adapted to provide a reduced abrasion of the piston.  
   
   
   
       18 . The pumping apparatus of  claim 1 , wherein the diamond-like carbon coating has a coating thickness ranging from 0.2 to 5 micrometers.