Two-Stage Linear Peristaltic Pump Mechanism

Abstract

This invention discloses a peristaltic pump composed of a two-stage linear peristaltic pump mechanism, which engages in different functions, charging and pumping a fluid to a patient. This peristaltic pump is capable of restoring the crushed tubing, caused by repeated compression or crushing of the tubing by peristaltic fingers, to its original circular cross sectional area so that it can provide a precise flow rate. The two-stage linear peristaltic pump mechanism substantially improves the consistency of a flow rate over time and extends the usefulness of peristaltic pumps to applications where they could not otherwise be used.

What is claimed is: 
     
         1 . A peristaltic pump configured to act on a piece of tubing in fluid communication with a reservoir containing a fluid, the peristaltic pump comprising a two-stage linear peristaltic pump mechanism, wherein one stage of the two-stage linear peristaltic pump mechanism ensures a crushed area of the tubing on which the other stage of the two-stage linear peristaltic pump mechanism operates is returned to an original cross sectional area and to provide a consistent flow rate of the fluid through said piece of tubing. 
     
     
         2 . A peristaltic pump as recited in  claim 1 , wherein the two-stages of the linear peristaltic pump mechanism comprise a charging mechanism configured to be positioned along an upstream charging section of the piece of tubing and a pumping mechanism configured to be positioned along a downstream pumping section of the piece of tubing, the charging mechanism and pumping mechanism cooperating such that when the pumping mechanism is not operating, the charging mechanism operates on the charging section of the tubing to fill the pumping section of the tubing with the fluid, and such that when said charging mechanism is not operating, the pumping mechanism operates on the pumping section of the tubing to moves said fluid further along. 
     
     
         3 . A peristaltic pump as recited in  claim 2 , wherein the charging mechanism comprises a charging shaft and a plurality of peristaltic charging fingers sized around the charging shaft, wherein the pumping mechanism comprises a pumping shaft and a plurality of peristaltic pumping fingers sized around the pumping shaft. 
     
     
         4 . A peristaltic pump as recited in  claim 3 , further comprising a backing member cooperating with the charging mechanism and the pumping mechanism such that when the charging mechanism is operating, the charging shaft turns the plurality of peristaltic charging fingers to compress the charging section of the tubing against the backing member, and when the pumping mechanism is operating, the pumping shaft turns the plurality of peristaltic pumping fingers to compress the pumping section of the tubing against the backing member. 
     
     
         5 . A peristaltic pump as recited in  claim 4 , further comprising a charging occluder mechanism positioned to act downstream of the charging section of the tubing. 
     
     
         6 . A peristaltic pump as recited in  claim 5 , wherein the charging occluder mechanism comprises at least one finger of the plurality of peristaltic charging fingers downstream of the charging section of the tubing. 
     
     
         7 . A peristaltic pump as recited in  claim 4 , further comprising a pumping occluder mechanism positioned to act downstream of the pumping section of the tubing. 
     
     
         8 . A peristaltic pump as recited in  claim 7 , wherein the pumping occluder mechanism comprises at least one finger of the plurality of pumping fingers, or an occluder finger downstream of the pumping section of the tubing. 
     
     
         9 . A peristaltic pump as recited in  claim 8 , wherein the occluder finger, fitting around the pumping shaft, is connected with a bias element with an end fixed onto the peristaltic pump, wherein the occluder finger is pulled away from the tubing by the bias element when the pumping mechanism is in operation. 
     
     
         10 . A peristaltic pump as recited in  claim 3 , wherein the pumping shaft is a crank shaft or a cam shaft, wherein the charging shaft is a crank shaft or a cam shaft. 
     
     
         11 . A peristaltic pump as recited in  claim 2 , further comprising at least one driver, wherein said at least one driver is connected to turn at least one from the group consisting of said charging mechanism and said pumping mechanism. 
     
     
         12 . A peristaltic pump as recited in  claim 11 , wherein the at least one driver is at least one motor. 
     
     
         13 . A peristaltic pump as recited in  claim 12 , wherein a single motor is connected to turn both the charging mechanism and the pumping mechanism. 
     
     
         14 . A peristaltic pump as recited in  claim 13 , further comprising at least two clutches, wherein the at least two clutches are connected to said motor turning said charging mechanism to operate on said charging section of the tubing when said motor rotates in a first direction while disengaging said pumping mechanism, and turning said pumping mechanism to operate on said pumping section of the tubing when said motor rotates in a second direction while disengaging said charging mechanism. 
     
     
         15 . A peristaltic pump as recited in  claim 14 , wherein said at least two clutches are roller clutches. 
     
     
         16 . A peristaltic pump as recited in  claim 15 , further comprising a first roller clutch and a second roller clutch, wherein said first roller clutch is connected for turning said charging mechanism, wherein said second roller clutch is connected for turning said pumping mechanism. 
     
     
         17 . A peristaltic pump as recited in  claim 16 , comprising at least one first gear coupled with the first roller clutch in connection with and turning said charging mechanism, and at least one second gear coupled with the second roller clutch in connection with and turning said pumping mechanism. 
     
     
         18 . A peristaltic pump as recited in  claim 2 , wherein the charging mechanism and the pumping mechanism are operated in a successive series. 
     
     
         19 . A peristaltic pump as recited in  claim 14 , further comprising an encoder controlling the turning speed and direction of the motor. 
     
     
         20 . A peristaltic pump as recited in  claim 19 , further comprising a transducer configured and positioned on said pump to be in contact with an outer wall of the pumping section of the tubing, the transducer configured to indicate when the pumping section of the tubing has been fully filled and is fully extended, or has been filled to an extent as specified with the fluid, said transducer cooperating with the motor and charging mechanism to cease charging mechanism operation and start the pumping mechanism in response to such indication.