Low flow constant rate pump

• US 4,468,220 A
• Filed: 04/05/1982
• Issued: 08/28/1984
• Est. Priority Date: 04/05/1982
• Status: Expired due to Fees

• Current Assignee: Milliken Research Corporation
• Original Assignee: Milliken Research Corporation
• Inventors: Willbanks, Charles E.
• Primary Examiner(s): Pellegrino, Stephen C.
• Application Number:
  US06/365,316
• Time in Patent Office: 876 Days
• Field of Search: 604/890, 604/891, 604/140, 604/145, 604/131, 604/133, 604/30, 222/386.5, 222/399
• US Class Current: 604/140
• CPC Class Codes: A61M 31/002 Devices for releasing a drug at a continuous and controlled rate for a prolonged period of time artificial gland structures or devices A61F2/022; intra-uterine contraceptive devices A61F6/14; tampons for introducing into the vagina A61F13/20, A61L15/00; suppositories or bougies for intra-vaginal or intra-uterine application A61K9/02; physical forms of medicinal preparations for sustained or differential drug release A61K9/20, A61K9/50
• CPC Class Codes: F16N 11/10 by pressure of another fluid

Abstract

A low flow, constant rate pump is provided which comprises a fixed volume container, the inner walls of said container defining a receptacle for a liquid to be dispensed, said container being provided with means to form an unobstructed opening through which said liquid may be caused to flow continuously at a low-flow, constant rate, a propellant chamber within said container formed of a material which is permeable to vapor from a propellant of the liquid-vapor type, a supply of propellant of the liquid-vapor type confined within said chamber, said propellant initially being under pressure sufficient to maintain a major portion thereof in liquid form at normal temperatures.

Claims

1. A low flow, constant rate pump which comprises a fixed volume container, the inner walls of said container defining a receptacle for a liquid to be dispensed, said container being provided with means to form an unobstructed opening through which said liquid may be caused to flow continuously at a low-flow, constant rate, a propellant chamber within said container formed of a material which is permeable to vapor from a propellant of the liquid-vapor type, a supply of propellant of the liquid-vapor type confined within said chamber, said propellant initially being under pressure sufficient to maintain a major portion thereof in liquid form at normal temperatures, and wherein said propellant chamber within said container is itself encompassed by a flexible diaphragm impermeable to said propellant vapor and to said liquid to be dispensed, thereby separating said propellant vapor from said liquid.