MXPA00009511A - Peristaltic pump and cassette - Google Patents

Abstract

A peristaltic pump and cassette assembly comprises a pump having a rotatable roller head (12,14,16) adapted to engage and pinch a portion of a flexibly walled fluid channel (26) contained in the cassette (18) and to be in operative association therewith to push fluid contained therein along the channel. The roller head (14) is attached to a rotatable shaft (24) and has one or more rollers (16) with longitudinal axes, the longitudinal axes of the rollers being generally normal to the axis of the shaft. The flexibly walled fluid channel is formed by at least one molded channel (26) defined in a flexible sheet (20) attached to a planar exterior substrate (22) on the cassette (18).

Description

PERISTALTIC PUMP AND CASSETTE BACKGROUND OF THE INVENTION The present invention relates generally to peristaltic pumps and more specifically to peristaltic pumps used in ophthalmic surgical equipment. Most peristaltic pumps work by compressing or squeezing a stretch of flexible tubing (sometimes between a fixed stroke) that uses a rotating roller head As the roller head the rollers hold a portion of the tubing and push any fluid trapped in the tubing between the rollers in the direction of rotation Peristaltic pumps are widely used in medical applications because of their properties constant flow, predictable These prior art systems, however typically require manual connection of the pump tube segment around the rotating roller head. The prior art peristaltic pumps using rotating roller heads also typically impart pu Undesired pressure reactions Various pulsation damping devices have been developed to address this problem (see v. US Patent No. 4921,477 (Davis)). Consequently, there continues to be a need for a peristaltic pump that reduces pressure pulsations and that It is simpler and cheaper to manufacture and use.

Brief Summary of the Invention The present invention improves the peristaltic pumps of the prior art by providing a peristaltic pump having a molded flow channel contained in an elastomeric sheet that is mechanically bound or fixed to a rigid substrate. The pump head rollers are mounted radially from the axis d? rotation of the pump motor and compress the elastomeric flow channels against the rigid substrate. An object of the present invention is to provide a peristaltic pump that uses molded metal flow channels. Another object of the present invention is to provide a peristaltic pump having radially oriented pump rollers. Still another object of the present invention is to provide a peristaltic pump having rollers d? pump compressing the elastomeric flow channels against a rigid substrate These and other advantages and objects of the present invention will become apparent from d? the following detailed description drawings and claims that follow BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 TS shows a schematic top plan view of a first embodiment of the present invention with the motor and head d? roller removed for clarity Figure 2 is a schematic side elevational view d? a first modality d? the present invention, with the motor and the head d? roll removed for clarity Figure 3 is a cross sectional view of the first embodiment of the present invention, taken on line 3-3 in Figure 1; Figure 4 is a schematic top plan view d? a second mode d? the present invention, with the motor and the roller head removed for clarity Figure 5 is a schematic side elevational view of a second embodiment of the present invention with the motor and the roller removed for clarity Figure 6 TS a view in schematic front elevation of a second embodiment of the present invention, with the motor and the roller head removed for clarity Detailed Description of the Invention As best seen in Figures 1, 2 and 3, in a first embodiment of the present invention, the pump 10 of the present invention generally includes the pump motor 12, the roller head 14, which contains one or more rollers 16 and cassette 18 having an elastomeric sheet 20 applied to the outside of a relatively rigid body or substrate 22 The motor 12 d? The preferred pump is a C D servo or stepping motor. The roller head 14 is fixed to the -15 arrow 24 of engine 12 so that engine 12 makes ^ turn the roller head 14 in a plane generally normal to the axis of the arrow 24, and the longitudinal axes of the rollers 16 are generally radial to the ee of the arrow 24 20 The sheet 20 contains the molten fluid channel 26 which is generally flat, arched in configuration (inside flat) and having a radius that approaches that of the rollers 16 around the arrow 24 The fluid channel 26 connects to fluid the Scuttles 28 and 30 The sheet 20 can be made of any appropriately flexible, easily molded material such as silicone rubber or thermoplastic elastomer. The sheet 20 is fixed or bonded to the substrate 22 by any suitable technique such as adhesive, thermal fusion or mechanical embossing. The substrate 22 is preferably made of a material that is rigid with respect to the sheet 20, such as a rigid thermoplastic, and can be made by any suitable method, such as machining or injection molding In use the cassette 18 is kept in close proximity to the head 14 d? roller so that the rollers 16 compress the channel 26 against the substrate 22 as the roller head 14 rotates. The longitudinal rolls are arranged so that the roller 16 in contact with the channel 26 is generally parallel to the roller. flat channel 26 Said arrangement eliminates the need to link a length of flexible tubing over the pump roller head and thereby simplifies loading of the pump channel 26 against the pump roller head 14 The rollers 16 may be tapering along its axial length to accommodate the difference in path length traveled by the inner and outer sections of the rollers 16 as the head 14 d rotates? The unwanted pressure pulsations could be minimized by providing channel transition regions 46 and 47 having internal cross sections that taper from zero to the full cross section of the channel 26. These regions minimize the abrupt change in volume displaced to As the rollers 16 transition into and out of the channel 26 As best seen in Figures 4-6, in a second embodiment of the present invention, the cassette 18 'may contain additional fluid channels that provide irrigation fluid control as well as suction fluid For example, the cassette 18 'may contain the inlet port 32 d? suction and suction outlet port 34 which are connected through channel 26 'Upstream of port 32, cassette 18' may contain pressure sensor 36, which may be any of a variety of non-invasive pressure sensors such as as those described in U.S. Patent No. 5,910,110 (Bastable) and U.S. Patent No. 5,470,312 (Zanger, et al), the entire contents of which is incorporated herein by reference. Cassette 18 'may also contain a vent fastening valve site 38 for allow the venting of any vacuum from the channel 26 'The irrigation fluid enters the cassette 18' through the port 40 and leaves the cassette 18 'through the gate 42 and is controlled by valve or site 44 of the clamping valve, which it can be actuated by a plunger (not shown) Ventilation 38 can be operated in a similar method Also, between port 40 and site 44 d? valve d? Irrigation fastener, the cassette 18 'may contain the irrigation pressure head 50 The pressure head 50 may be made of a thin molded membrane contained within the elastomeric sheet 20' on a fluid chamber (not shown) in a manner non-invasive using a surface contact pressure transducer or calibrated load cell This description is provided for purposes of illustration and explanation It will be apparent to those skilled in the related art that modifications to the invention can be made as described herein without abandoning your reach or spirit

Claims (11)

1 - . 1 - A cassette for use with a peristaltic pump having a roller head, comprising a) a body having an exterior, b) a sheet fixed to the body, the sheet containing at least one molded fluid channel, the channel fluid being generally arcuate

2 - The cassette according to claim 1 wherein the roller head contains one or more arcuately spaced rollers and the arcuate configuration of the fluid channel approximates a radius of the rollers

3 - The cassette of conformity with claim 1, wherein the sheet comprises a molded suction fluid channel and a molded irrigation fluid channel

4 - The cassette according to claim 1 wherein the sheet comprises a flexible, easily molded material

5 - The cassette according to claim 4, wherein the sheet comprises silicone rubber or thermoplastic elastomer

6 - The cassette in accordance with the Claim 1, wherein the fluid channel is flat

7 - The cassette according to claim 1, wherein the fluid channel has at least one transition region

8 - The cassette according to claim 1, wherein the channel fluid has at least one clamping valve site

9 - The cassette according to claim 1, wherein the substrate has at least one molded membrane pressure interface

10 - A peristaltic pump comprising a) a pump roller head , a roller head fixed to a rotating shaft and having one or more rollers with longitudinal axes of the rollers that is generally normal to the axis of the arrow b) a cassette having a body having an exterior, c) a fixed plate to the body, the sheet containing at least one molded fluid channel, the fluid channel being retained in operative association with the rollers in the roller head

11 - The pump c according to claim 10, wherein the fluid channel TS arcuate and remains in one plane and the longitudinal axes of the rollers are arranged so that the roller makes contact with the fluid channel is generally parallel with the fluid channel. 12, - The pump according to claim 10, wherein the rollers are generally tapered.