US 6,162,030 AGranted

Zero leakage valveless positive fluid displacement device

AssigneeEncyNova International, Inc.

InventorMichel A. Pierrat

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Abstract

A Positive Fluid Displacement Device (PFDD) with a removable Fluid Displacement Module (FDM) having two opposing pistons connected to a drive block. The drive block slides over a crankpin bearing in assembly to provide orbital piston motion. Opposing cylinders are held within a carriage for reciprocating motion. An opening in the reciprocating cylinder head allows fluid communication to the displacement chamber through inlet and outlet ports in a floating port plate. The flat surfaces of the port plate and cylinder head wipe across each other during cylinder head movement. The piston head carries a protrusion sized to fill the cylinder head opening. Micro-adjustment mechanisms for the position of the cylinder head together with compliant piston and compliant cylinder mechanisms can provide near zero dead volume. Different sized opposing cylinders enable the delivery of pumped fluids in precise ratios. By connecting the outlet of each cylinder to the inlet of the opposing cylinder, the differential displacement of the two cylinders can be pumped, enabling the delivery of very small quantities of fluid. High vacuum may be delivered by series connection of cylinders. The device may incorporate a dual lip piston seal which is wear compensated over the life of the seal. The PFDD is leakage free and can be driven by stepper motors to deliver a precise fluid amount at low speed even to an exact portion of a piston stroke. A sensor is provided for sensing cylinder head position.

Claims53

Dependent claims

A positive fluid displacement device (PFDD) for delivering a fluid comprising

a housing for said device;
a crankshaft mounted within said housing, said crankshaft for coupling to the driveshaft of a motor;
a crankpin connected to said crankshaft to provide an orbital movement around said crankshaft;
a fluid displacement module (FDM) for quick and easy assembly with said housing and said crankpin, said FDM having a first piston/cylinder assembly comprising
a piston having a connecting end and a piston head, said connecting end connected to said crankpin to operably provide said piston with a circular motion;
a cylinder having a cylinder head, said cylinder head having a side enclosing one end of a displacement chamber, said cylinder for holding said piston, said piston head enclosing a second end of said displacement chamber;
said cylinder head having a flat surface on a side opposite to the side enclosing said displacement chamber;
and
an opening in said cylinder head, said opening allowing fluid communication to and from said displacement chamber, said piston head having a protrusion sized to fill said opening;
a first port plate having a flat surface which in assembly is in sealing engagement with the flat surface of said cylinder head, said port plate having two ports for fluid communication through said opening to said displacement chamber, one port being an inlet port to said displacement chamber and one port being an outlet port from said displacement chamber, in assembly said housing acts to hold said port plate from any substantial movement in two dimensions while allowing movement in one dimension;
a port plate spring located in assembly between said housing and said port plate to urge the flat surface of said port plate in said one dimension into sealing engagement with the flat surface of said cylinder head wherein said port plate is urged against said cylinder head in floating engagement therewith;
wherein in operation, the circular movement of said crankpin imparts a reciprocating movement to said cylinder, the flat surface of said cylinder head moving back and forth across the flat surface of said port plate once per revolution of said crankpin wherein said opening is successively brought into fluid communication with said inlet port and said outlet port;
said FDM having a second piston/cylinder assembly identical to said first piston/cylinder assembly, the second piston having a connecting end connected to said crankpin to provide an opposing piston/cylinder assembly;
and
a second port plate associated with said second piston/cylinder assembly, said second port plate identical to said first port plate.

12 more elements

A method of eliminating valves and achieving near dead volume in a positive fluid displacement device (PFDD) employing pistons to draw fluid into displacement chambers and expel fluid therefrom, and to eliminate internal leakage in said PFDD, said method comprising

providing a PFDD housing with a crankshaft and a crankpin, said crankpin providing circular motion around said crankshaft;
providing at least two pistons capable of being driven by said crankpin in a circular motion;
providing at least two cylinders, each cylinder having a cylinder head, said cylinders capable of being driven by said crankpin in a reciprocating motion;
providing an opening in each cylinder head for allowing fluid communication to and from the displacement chambers;
providing a protrusion on each piston, said protrusion sized to fill said opening when the piston is at top dead center to achieve near zero dead volume in the displacement chamber;
providing inlet and outlet ports for allowing alternating fluid communication through the opening to fill the displacement chamber on an intake stroke of the piston and to empty the displacement chamber on an exhaust stroke of the piston to achieve valveless operation;
providing a port plate containing said inlet and outlet ports, said port plate having a flat surface for mating with a flat surface on said cylinder head to provide a sealing relationship therebetween;
providing for a port plate mounting arrangement that allows said port plate to move in one dimension to maintain the sealing relationship with said cylinder head and to accommodate sufficient clearance of said cylinder head in two other dimensions to allow for movement in said one dimension;
and
providing for the maintenance of sufficient force on said port plate in a dimension perpendicular to the plane of reciprocating motion to maintain said sealing relationship and thereby eliminate internal leakage in said PFDD.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/096,519Filed 12 Jun 1998
Granted: 19 Dec 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

F04B 1/0472
With actuating or actuated elements at the outer ends of the cylinders: with cam-actuated distribution members
F04B 1/07
Control: by varying the relative eccentricity between two members, e.g. a cam and a drive shaft
F04B 27/0472
With an actuating element at the outer ends of the cylinders: with cam-actuated distribution members
F04B 49/128
By changing the eccentricity of one element relative to another element: by changing the eccentricity of the cylinders, e.g. by moving a cylinder…