Device for Receiving and Dispensing Liquids

Abstract

The invention relates to a device for receiving and dispensing liquids, the device comprising a plurality of piston-cylinder units ( 1, 1′, 1 ″) which are respectively arranged on a piston plate ( 2 ) and a cylinder plate ( 3 ). According to the invention, the liquid is received and dispensed by displacing the pistons ( 1 ′) in the cylinders ( 1 ″) by changing the distance between the plates ( 2, 3 ), perpendicularly to the plate planes, by means of a drive mechanism ( 6 ) and a plate guiding system. The volume can be determined by an upper abutment ( 4 ) and a lower abutment ( 5 ), at least one of said abutments being regulatable by a regulating means ( 8 ). The aim of the invention is to render one such device suitable for handling precise volumes of a larger number of piston-cylinder units ( 1, 1′, 1 ″) in a technically simple manner. To this end, the same receiving and dispensing volumes of the piston-cylinder units ( 1, 1′, 1 ″) are ensured with low requirements in terms of the surface parallelism of the plate planes during the movement in the plate guiding device, by structuring and arranging the abutments ( 4, 5 ) in such a way that the parallelism of the plates ( 2, 3 ) is obtained in the upper ( 9 ) and lower ( 10 ) abutment positions.

1 - 30 . (canceled)  
   
   
       31 . A device for receiving and dispensing liquids, the device comprising: 
 a piston plate having a plurality of pistons;    a cylinder plate defining a plurality of cylinders, wherein each piston engages one cylinder;    a drive mechanism cooperating with at least one of said piston plate and said cylinder plate to receive and dispense the liquids by changing a separation between said piston plate and said cylinder plate to displace said pistons in said cylinders;    a plate guidance to direct relative motion between said piston plate and said cylinder plate in a direction substantially perpendicular to planes of extension thereof;    an upper stop having an upper stop position;    a lower stop having a lower stop position; and    a liquid volume adjusting means cooperating with at least one of said upper stop and said lower stop to cause said piston plate and said cylinder plate to assume a mutually parallel configuration at abutment with said lower stop and said upper stop, independent of a degree to which said piston plate and said cylinder plate maintain said mutually parallel configuration at varying separations from said upper stop and said lower stop, to precisely define equal dosed liquid volumes for all pistons and cylinders.    
   
   
       32 . The device of  claim 31 , wherein each of said upper and said lower stops defines at least three stop points which abut an outer surface area of a respective said piston plate and said cylinder plate.  
   
   
       33 . The device of  claim 32 , where said upper and lower stops comprise means for adjusting a parallelism of stop positions.  
   
   
       34 . The device of  claim 32 , wherein said liquid volume adjusting means is designed such that stop points of said upper and lower stops can be simultaneously adjusted in height.  
   
   
       35 . The device of  claim 34 , wherein said stop points can be adjusted by stepping motors.  
   
   
       36 . The device of  claim 34 , wherein said stop points are simultaneously adjusted using a transmission.  
   
   
       37 . The device of  claim 31 , wherein said piston plate, said cylinder plate, said upper stop, and said lower stop are disposed in a pipetting head which is suspended on a stand using a vertical guidance.  
   
   
       38 . The device of  claim 37 , wherein said stand has means for positioning said pipetting head towards a working plate which serves for pipetting and aligning a grid arrangement of said pistons and cylinders with a grid arrangement of positions on said working plate.  
   
   
       39 . The device of  claim 38 , wherein said positioning means cooperate with at least one said working plate for motion thereof into alignment with said grid arrangement of said pistons and said cylinders.  
   
   
       40 . The device of  claim 39 , wherein said positioning means are disposed on a rotary disc.  
   
   
       41 . The device of  claim 39 , wherein said stand comprises a horizontal guidance for said pipetting head and several mutually adjacent positioning means, disposed below said horizontal guidance, for working plates and with positioning aids for grid alignment.  
   
   
       42 . The device of  claim 39 , wherein several positioning means for working plates are structured for displacement, using at least one horizontal guidance, to positions defined by positioning aids, such that associated working plates can be aligned with said grid arrangement of said pistons and said cylinders.  
   
   
       43 . The device of  claim 38 , wherein at least one lower stop defines a vertical motion of said pipetting head.  
   
   
       44 . The device of  claim 43 , wherein said at least one lower stop adjusts an immersion depth into liquid receptacles of said working plate.  
   
   
       45 . The device of  claim 43 , wherein each positioning means for said working plate has an associated stop.  
   
   
       46 . The device of  claim 37 , wherein said vertical guidance of said pipetting head has a weight balancing means which is structured for smooth vertical motion using little force.  
   
   
       47 . The device of  claim 46 , wherein said vertical guidance of said pipetting head has an associated lift stop, which responds to excessive acceleration.  
   
   
       48 . The device of  claim 31 , wherein a drive mechanism for said pistons and said cylinders can be operated by a hand lever having a transmission.  
   
   
       49 . The device of  claim 48 , wherein said drive mechanism acts on said piston plate.  
   
   
       50 . The device of  claim 49 , wherein said drive mechanism moves said piston plate into said lower stop position and restoring springs return said piston plate to said upper stop position.  
   
   
       51 . The device of  claim 31 , wherein said pistons are sealed from said cylinders.  
   
   
       52 . The device of  claim 51 , wherein said cylinder plate is divided in a horizontal direction and elastic sealing material is embedded in such a fashion that means for compressing the plate parts can adjust cylinder diameters at sealing locations, wherein said pistons move in an area of said sealing locations.  
   
   
       53 . The device of  claim 37 , wherein lower ends of said cylinders have receiving means for disposing liquid receptacles or pipette tips thereon.  
   
   
       54 . The device of  claim 53 , wherein said receiving means have elastic rings.  
   
   
       55 . The device of  claim 53 , wherein, for receiving said liquid receptacles or said pipette tips, a force transmission effects relative pressing movement between said pipetting head and a liquid receptacle support or a pipette tip support located in a positioning means.  
   
   
       56 . The device of  claim 55 , wherein said force transmission comprises a transmission lever which acts between said stand and said pipetting head, forcing the latter against said liquid receptacle support or said pipette tip support.  
   
   
       57 . The device of  claim 53 , further comprising a liquid receptacle or pipette tip wiper.  
   
   
       58 . The device of  claim 57 , wherein said liquid receptacle or pipette tip wiper is a perforated plate which can be operated by a lever, is disposed below said cylinder plate, and can be vertically displaced, said plate having holes which are larger than said receiving means but smaller than said liquid receptacles or pipette tips.  
   
   
       59 . The device of  claim 31 , wherein said lower stop comprises a latch, by means of which a moved plate can be moved further by overcoming a retaining force forming a stop position of a stop or by effecting release of said latch, in order to blow out residual liquid.  
   
   
       60 . The device of  claim 31 , further comprising at least one adjustable grid-like intermediate stop disposed between said upper and said lower stops for dosing received liquid, wherein said intermediate stop also effects parallel alignment of said piston and cylinder plates and can be overcome by an increased force or by releasing a latch.