Piezoelectric fluid injector

• US 4,345,595 A
• Filed: 03/27/1981
• Issued: 08/24/1982
• Est. Priority Date: 01/08/1979
• Status: Expired due to Fees

• Current Assignee: Douglass G. Whitney, John K. Martin III
• Original Assignee: Douglass G. Whitney, John K. Martin III
• Inventors: Whitney, Douglass G., Martin, John K. III
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US06/248,566
• Time in Patent Office: 515 Days
• Field of Search: 128/214 F, 128/214 R, 128/214 E, 128/213, 128/215, 128/218 A, 128/253, 128/260, 222/63, 222/70, 222/77
• US Class Current: 604/31
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61M 2005/14506 mechanically driven, e.g. spring or clockwork
• CPC Class Codes: A61M 2205/0294 Piezoelectric materials
• CPC Class Codes: A61M 39/04 having pierceable self-sealing members
• CPC Class Codes: A61M 5/1422 with double acting or multiple pistons
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/155 pressurised by gas introduced into the reservoir
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: Y10S 128/01 Motorized syringe
• CPC Class Codes: Y10S 128/12 Pressure infusion
• CPC Class Codes: Y10S 128/13 Infusion monitoring

Abstract

Method and apparatus for injecting fluids into patients at a controlled rate from an ampule containing the injecting fluid with a sliding piston therein to force the fluid from the ampule into the patient using a drive system which incrementally and successively advances the piston in the ampule to meter the fluid into the patient.

Claims

1. Apparatus for injecting fluid into a patient at an average prescribed rate over a prolonged period of time comprising:

carriage means defining a fluid chamber therein carrying fluid to be dispensed and an outlet from said fluid chamber connected to the patient;

a piston slidably mounted in said fluid chamber for forcing fluid from said outlet as said piston is moved toward said outlet;

an electrical power supply;

electrically operated driving means for moving said piston toward said outlet when said electrically operated driving means is connected to said power supply, said electrically operated driving means constructed and arranged to move said piston only a prescribed distance toward said outlet each time said electrical power supply is connected to said electrically operated driving means regardless of the length of time said electrical power supply is connected to said electrically operated driving means, said piston forcing a volume of the fluid from said outlet much less than the total volume of fluid to be injected over the prolonged period of time each time said piston is moved said prescribed distance; and

control means for selectively connecting said electrical power supply to and disconnecting said electrical power supply from said electrically operated driving means at a rate such that fluid is injected into the patient at the desired average rate over the prolonged period of time so that, if said control means fails so as to continuously connect said electrical power supply to said electrically operated driving means, said piston will be moved only said incremental prescribed distance toward said outlet to prevent overdosing the patient,

said driving means including a driving member exhibiting a piezoelectric effect and linkage means connecting said driving member to said piston so that the change in volume experienced by said driving member when said control means connects said power supply to said driving member moves said piston toward said outlet.