SYRINGE BARREL WIPER FOR LIQUID DISPENSING
A syringe for syringe pumps or like instruments is disclosed, having a modified plunger disposed with a barrel wiper for enhancing seal life of the syringe. The syringe comprises a cylindrical barrel that is slideably engaged to a plunger via a seal. The syringe barrel wiper provides for enhanced seal life by extended controlled lubrication to inhibit debris adherence and reduced seal friction by wiping the inside of the barrel to remove debris buildup and egress of debris. The wiper comprises a lubricant-permeated porous polymer material shaped as a cylindrical tubular member.
1 . A syringe for dispensing fluids, comprising:
a cylindrical barrel having a distal end and a proximal end;
the barrel having a chamber emanating at an opening at the proximal end and terminating near the distal end;
a plunger configured to reciprocate axially inside the chamber;
the plunger comprising a distal end having a seal, and a proximal end comprising an arm terminating at a location outside the chamber;
wherein the seal is configured to slideably engage an inside wall of the chamber; and
a wiper disposed on the plunger proximal to the seal;
wherein the wiper holds a volume of lubricant;
wherein the wiper is sized to engage the inner surface of the chamber so that the lubricant is disposed on the inner surface as the plunger reciprocates in the chamber.
2 . A syringe as recited in claim 1 , wherein the wiper comprises a porous polymer permeated with the volume of lubricant.
3 . A syringe as recited in claim 1 , wherein the wiper has a cylindrical outer surface that forms an interference fit with the inner surface of the chamber when installed in the chamber.
4 . A syringe as recited in claim 3 :
wherein the wiper is slideably disposed on the plunger so that a gap is formed between the distal end of the wiper and the proximal end of the seal as the plunger travels distally in the chamber; and
wherein the gap is configured to collect debris from the inner surface of the chamber.
5 . A syringe as recited in claim 4 :
wherein the wiper has a central channel configured to be disposed over a step-reduced section of the plunger;
the step-reduced section extending a specified length between the proximal end of the seal and the arm of the plunger;
wherein a recess is formed between the wiper and the step-reduced section; and
wherein the recess facilitates migration of the debris proximally along said plunger.
6 . A syringe as recited in claim 5 :
wherein the length of the step-reduced section is longer than the length of the wiper so that distal reciprocation of the plunger in the chamber causes the wiper to slide axially to the plunger arm at the proximal end of the step-reduced section to form the gap at the distal end;
said gap being in fluid communication with said recess.
7 . A syringe as recited in claim 6 , wherein proximal reciprocation of the plunger in the chamber causes the wiper to slide axially to the seal at the distal end of the step-reduced section to form a gap between the proximal end of the wiper and the plunger arm to facilitate egress of the collected debris out of the chamber.
8 . A syringe as recited in claim 7 , wherein the wiper is tubular having an inner diameter defined the central channel; and
wherein the step reduced section comprises a diameter that is smaller than the inner diameter of the wiper to create said recess.
9 . A syringe as recited in claim 5 , wherein the wiper has a slit running axially down the length of the wiper;
wherein the slit allows the wiper to be installed on the step-reduced section.
10 . A syringe assembly for dispensing fluids, comprising:
a cylindrical barrel having a distal end and a proximal end;
the barrel having a chamber emanating at an opening at the proximal end and terminating near the distal end;
a plunger configured to reciprocate axially inside the chamber, comprising:
a distal end having a seal configured to slideably engage an inside wall of the chamber;
a proximal end comprising an arm extending to a location outside the chamber; and
a neck disposed between the seal and the arm;
the neck having a smaller cross-section than the arm and the seal; and
a wiper disposed on the plunger proximal to the seal;
wherein the wiper is disposed over the neck via a central channel in the wiper;
wherein the central channel of the wiper is shaped to form a recess between the wiper and the neck said recess running axially along the length of the wiper;
wherein the wiper has an outer diameter configured to engage the inner wall of the chamber to scrape debris from the wall;
wherein the recess allows migration of the debris to a location outside the chamber.
11 . A syringe assembly as recited in claim 10 :
wherein the wiper is configured to retain a volume of lubricant; and
wherein the wiper distributes the lubricant to coat the inner wall of the chamber with the lubricant as the plunger reciprocates in said chamber.
12 . A syringe assembly as recited in claim 11 , wherein the wiper comprises a porous polymer that is permeated with the volume of lubricant and distributes the lubricant from contact with the inner wall of the chamber.
13 . A syringe assembly as recited in claim 10 :
wherein the wiper has a length that is smaller than the length of the neck;
wherein the wiper is slideably disposed on the neck of the plunger such that, the proximal end of the wiper abuts against the arm of the plunger when the plunger is travelling toward the distal end of the chamber; and
wherein a gap is formed between the distal end of the wiper and the seal, the gap allowing fluid communication from the inner wall of the chamber to the recess between the wiper and the neck.
14 . A syringe assembly as recited in claim 13 :
wherein the distal end of the wiper abuts against the seal when the plunger is travelling toward the proximal end of the chamber to form a gap between the proximal end of the wiper and the arm;
wherein the gap between the proximal end of the wiper and the arm allows debris egress from the recess to a location external to the chamber.
15 . A syringe assembly as recited in claim 10 , wherein the central channel of the wiper has a diameter that is larger than the diameter of the neck to form an annular recess between the wiper and the neck.
16 . A syringe assembly as recited in claim 10 , wherein the central channel of the wiper comprises a groove to facilitate migration of debris proximally out said chamber.
17 . A syringe pump assembly, comprising:
a cylindrical barrel having a distal end and a proximal end;
the barrel having a chamber emanating at an opening at the proximal end and terminating near the distal end;
a valve in fluid communication with the distal end of the chamber;
a plunger configured to reciprocate axially inside the chamber, comprising:
a distal end having a seal configured to slideably engage an inside wall of the chamber;
a proximal end comprising an arm extending to a location outside the chamber;
a neck disposed between the seal and the arm;
the neck having a smaller cross-section than the arm and the seal; and
a wiper disposed on the plunger proximal to the seal;
wherein the wiper is disposed over the neck via a central channel in the wiper; and
a reciprocating arm coupled to the proximal end of the plunger arm, the reciprocating arm coupled to a motor for driving motion of the plunger inside the chamber;
wherein the wiper holds a volume of lubricant;
wherein the wiper is sized to engage the inner surface of the chamber so that the lubricant is disposed on the inner surface as the plunger reciprocates in the chamber.
18 . A syringe pump assembly as recited in claim 17 , wherein the wiper comprises a porous polymer permeated with the volume of lubricant and has a cylindrical outer surface that forms an interference fit with the inner surface of the chamber when installed in the chamber to dispense a layer of lubricant on the inner surface.
19 . A syringe pump assembly as recited in claim 18 :
wherein the wiper has a length that is smaller than the length of the neck;
wherein the wiper is slideably disposed on the neck of the plunger such that, the proximal end of the wiper abuts against the arm of the plunger when the plunger is travelling toward the distal end of the chamber to dispense fluid out of said chamber and through said valve; and
wherein a gap is formed between the distal end of the wiper and the seal, the gap allowing fluid communication from the inner wall of the chamber to the recess between the wiper and the neck.
20 . A syringe pump assembly as recited in claim 19 :
wherein the distal end of the wiper abuts against the seal when the plunger is travelling toward the proximal end of the chamber to aspirate fluid through the valve into the chamber;
the wiper forming a gap between the proximal end of the wiper and the arm to allows debris egress from the recess to a location external to the chamber.
21 . A syringe pump assembly as recited in claim 20 , wherein the central channel of the wiper has a diameter that is larger than the diameter of the neck to form an annular recess between the wiper and the neck.
22 . A syringe pump assembly as recited in claim 18 , wherein the wiper has a slit running axially down the length of the wiper;
wherein the slit allows the wiper to be installed on the neck.
23 . A syringe pump assembly as recited in claim 18 , wherein the plunger is separable to install the wiper on to the neck.