Systems and methods related to fluid pumping

Systems for a plastic pump/actuator capable of containing and pumping organic solvents and lubricants and having a more desirable lubricity within the system. The system has at least two cylinders, with plungers therein, oppositely disposed from each other and configured to operably connect to a pump.

BACKGROUND

This invention relates generally to a plastic reciprocating actuator with closure container for use with pumps requiring low resistance during pumping, for example for use with fluid dispensing systems and actuators. Generally, dispensers and actuators used in the medical field are metal, glass, or plastic and employ standard lubricants such as liquid, gel, or spray deposition lubricants, and utilize a rigid or compression gasket. The chemistry of the standard lubricants attack non-metal pumps, actuators, and seals (e.g., non-olefin plastics, thermoset plastics, liquid silicone rubber, polyisoprene, and some glass). Therefore, in circumstances in which organic solvents or other chemicals are used, certain silicone-based lubricants are incompatible and will damage or destroy the actuator cylinder, the pump, and the seals.

Further, metal actuators and pumps are incapable of providing visibility within the equipment; glass equipment may delaminate after usage and silicone-based lubricants cannot be used under harsh environments. Previously, plastic has not been used due to higher-than-desired static and kinetic friction within the system. Therefore, the field of medical devices is in need of a plastic pumping/actuating system that can contain and pump organic solvents and lubricants and has a more desirable surface tension within the system.

SUMMARY OF THE INVENTION

The present invention relates to improved systems and methods for a plastic pumping/actuating system capable of containing and pumping organic solvents and lubricants and has a more desirable lubricity within the system.

One aspect of the present invention is directed to a reciprocating actuator assembly with a first cylinder, a first plunger with a piston, a second cylinder configured to be coupled to and in fluid communication with the first cylinder, a second plunger with a piston configured to translate within the second cylinder, and a fluoropolymer coating applied within the first cylinder, within the second cylinder, and to the piston of the first plunger and the piston of the second plunger. Either or both of the first and second cylinders may comprise cyclic olefin copolymer (COC) or cyclo-olefin polymer (COP).

The first cylinder may have approximately a 1 cc capacity or a 3 cc capacity and whereby the static friction between the first cylinder and the first piston is less than about 2.5N. Alternatively, the first cylinder may have approximately a 3 cc capacity and whereby the static friction between the first cylinder and the first piston is less than about 4.0N.

The actuator assembly may also be configured to be operatively coupled to a pump, and wherein the first plunger may have a first end and a second end, wherein the first end of the plunger is received within the first cylinder and the second end of the plunger is received within a pump cylinder.

The actuator assembly may also have a check valve coupled between the first cylinder and the second cylinder, and the check valve may be configured to be removably coupled to a third cylinder with a third plunger.

Another aspect of the invention is directed to a method comprising the steps of providing a first plunger with a piston in a first cylinder containing a first substance, providing a second plunger with a piston in a second cylinder containing a second substance, whereby the first cylinder is in fluid communication with the second cylinder, transferring the second substance from the second cylinder to the first cylinder through movement of the first plunger, whereby the second substance mixes with the first substance and forms a mixture, and transferring the mixture from the first cylinder to the second cylinder through movement of the second plunger; whereby the first cylinder, the first piston, the second cylinder, and the second piston have a fluoropolymer coating. Whereby, the first substance may be a dry medicine and the second substance may be a liquid, and the first and second cylinders may comprise cyclic olefin copolymer (COC) or cyclo-olefin polymer (COP).

The first cylinder may have a capacity of approximately 1 cc and whereby the static friction between the first cylinder and the first piston is less than about 2.5N. Alternatively, the first cylinder may have a capacity of approximately 3 cc and whereby the static friction between the first cylinder and the first piston is less than about 4.0N.

The first plunger may have a first end and a second end, and the first end of the plunger may be received within the first cylinder and the second end of the plunger may be received within a pump cylinder.

The method may further comprise the steps of providing a check valve, coupling the check valve between the first cylinder and the second cylinder, providing a third cylinder with a third plunger, and coupling the third cylinder to the check valve.

DETAILED DESCRIPTION

Although the disclosure hereof enables those skilled in the art to practice the invention, the embodiments described merely exemplify the invention which may be embodied in other ways. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. It should be noted that like part numbers represent like parts among the various embodiments.

FIGS.1-4provide various views of an exemplary first embodiment100of a reciprocating actuator assembly. According to the present invention, the reciprocating actuator assembly100preferably comprises a first cylinder110; a first plunger116; a second cylinder130opposite the first cylinder110; and a second plunger136.

The reciprocating actuator system100is preferably configured to be operably connected to a pump10having a pump cylinder12(seeFIGS.9and10). The pump cylinder12is preferably configured to be receive the first or second plunger116,136.

The first cylinder110preferably comprises a first end portion112and a second end portion114. The first end portion112is preferably configured to removably attach to a first end portion132of the second cylinder130; whereby the first and second cylinders110,130are configured to be in fluid communication with each other. The second end portion114is preferably configured to receive the first plunger116therein and therethrough.

The first plunger116preferably comprises a first end portion118and a second end portion122. The first end portion118preferably comprises a first piston120. As shown inFIG.2, the first piston120is a separate element attached to the first end portion118of the first plunger116; however, it is contemplated that the first piston120and the first plunger116may be a unitary piece. The first piston120is preferably sized and configured to translate back and forth within the first cylinder110and prohibit blow-by when exposed to predetermined pressures. The second end portion122of the first plunger116is preferably configured to facilitate the transfer of at least one of an input force and an output force.

The second cylinder130preferably comprises the first end portion132and a second end portion134. The second end portion134is configured to receive the second plunger136therein and therethrough.

The second plunger136preferably comprises a first end portion138and a second end portion142. The first end portion138preferably has a second piston140. As shown inFIG.2, the second piston140is a separate element attached to the first end portion138of the second plunger136; however, it is contemplated that the second piston140and the second plunger136may be a unitary piece. The second piston140is preferably sized and configured to translate back and forth within the second cylinder130and prohibit blow-by when exposed to predetermined pressures. The second end portion142is preferably configured to facilitate the transfer of at least one of an input force and an output force.

The first and second cylinders110,130and the pump cylinder12preferably comprise cyclic olefin copolymer (COC) or cyclo-olefin polymer (COP). These polymers have similar barrier properties to glass but are not as fragile. COC and COP provide more resistance to the effects of organic solvents and provide superior optical clarity than glass. Forming the first and second cylinders110,130and the pump cylinder12from COC and COP also promotes mass production via injection molding and allow for tighter tolerances to be achieved than is possible with glass. It is contemplated, however, that other polymers may be used provided they have comparable properties.

Preferably a fluoropolymer coating50is applied as a dry lubrication within the first and second cylinders110,130and within the pump cylinder12(seeFIG.10). The fluoropolymer coating50promotes a reduction in the static friction between the first and second plungers116,136and the first and second cylinders110,130, respectively, and the pump cylinder12to less than or equal to about 2.5 Newtons for a 1 cc cylinder and less than or equal to about 4.0 Newtons for a 3 cc cylinder.

The first and second pistons120,140preferably comprise thermoplastic elastomer (TPE). However, it is contemplated that other polymers may be used provided they have comparable properties. Similar to the first and second cylinders110,130and the pump cylinder12, the fluoropolymer coating50is preferably applied as a dry lubrication to the first and second pistons120,140. The fluoropolymer coating50is preferably applied in a tumbler, whereby the duration of tumbling is directly proportional to the thickness of the coating.

As a non-limiting example, one proposed use for the reciprocating actuator assembly100is for mixing a dry medicine (not shown) with a liquid (not shown) to provide a mixture (not shown) to be administered to a patient (not shown). For example, the dry medicine is provided in the first cylinder110and a liquid to be mixed with the dry medicine is provided in the second cylinder130. The second plunger136is moved in the direction of the first cylinder110thereby injecting the liquid of the second cylinder130into the first cylinder110. The first plunger116is moved in the direction of the second cylinder130and the mixture of dry medicine and liquid is injected into the second cylinder130. This process is repeated until the mixture is adequately mixed. The first and second cylinders110,130may then be separated and the cylinder containing the mixture may be used to administer the mixture to the patient.

A second embodiment200of a reciprocating actuator assembly is shown inFIGS.5-8. The reciprocating actuator assembly200comprises many elements similar to those provided in the first embodiment100including a first cylinder210; a first plunger216with a first piston220; a second cylinder230opposite the first cylinder210; and a second plunger236with a second piston240. The reciprocating actuator assembly200preferably comprises a check valve260joining the first cylinder210and the second cylinder230, wherein the check valve260is configured to provide fluid communication between the first and second cylinders210,230and possibly a third device, for example a third cylinder with a third plunger (not shown). The reciprocating actuator assembly200is also preferably configured to be operably connected to the pump10shown inFIGS.9and10.

Also, similar to the first embodiment100, the first and second cylinders210,230and the pump cylinder12preferably comprise cyclic olefin copolymer (COC) or cyclo-olefin polymer (COP); however, it is contemplated that other polymers may be used provided they have comparable properties.

Like the first embodiment100described above, a fluoropolymer coating50is preferably applied as a dry lubrication within the first and second cylinders210,230and within the pump cylinder12. The fluoropolymer coating50promotes a reduction in the static friction between the first and second plungers216,236and the first and second cylinders210,230, respectively, and the pump cylinder12to less than about 2.5 Newtons for a 1 cc cylinder and less than about 4.0 Newtons for a 3 cc cylinder.

The first and second pistons220,240preferably comprise thermoplastic elastomer (TPE). However, it is contemplated that the other polymers may be used provided they have comparable properties. The fluoropolymer coating50is preferably applied as a dry lubrication to the first and second pistons220,240. The fluoropolymer coating50is preferably applied in a tumbler, whereby the duration of tumbling is directly proportional to the thickness of the coating.

The reciprocating actuator system200may be used in a similar manner as that of the first embodiment100, that is to facilitate the mixing of substances (not shown) to form a mixture (not shown). The reciprocating actuator system200is further configured to output the mixture and/or input an additional substance (not shown) through the check valve260.

As provided above, the reciprocating actuator systems100,200are preferably configured to be operably connected to the pump10(seeFIGS.9and10). The pump10has a pump cylinder12, a pump inlet14preferably with a check valve16, and a pump outlet18preferably with a check valve20, whereby the pump inlet14and pump outlet18facilitate movement of a substance (not shown) into and out of the pump cylinder12, respectively. As shown inFIG.10, the fluoropolymer coating50is provided on the inside surface of the pump cylinder12.

InFIGS.9and10the first plunger216of the reciprocating actuator assembly200is shown received within the pump cylinder12. The first plunger216further comprises a second piston224and is configured to translate back-and-forth within the pump cylinder12in directions A1and B1. When the first plunger216moves in direction A1, the substance (not shown) is drawn into the pump cylinder12through the inlet14, whereby the check valve16only allows the substance to flow in a flow direction A2. When the first plunger216moves in direction B1, the substance is pushed out of the pump cylinder12through the outlet18, whereby the check valve20only allows the substance to flow in a flow direction B2.

It is further contemplated that a check-valve (not shown) be provided either within the pump10or outside of the pump10and configured to promote substance flow in only flow direction A2when the first plunger216moves in direction A1and only in flow direction B2when the first plunger216moves in direction B1.

Although the pump10provides a reference of use for the reciprocating actuator systems100,200, it should not be viewed as limiting the capability of the reciprocating actuator systems100,200nor the pump10to these configurations.

The foregoing is illustrative only of the principles of embodiments according to the present invention. Modifications and changes will readily occur to those skilled in the art, so it is not desired to limit the invention to the exact disclosure herein provided. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.