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.

1 . A peristaltic pump having a piece of tubing in a fluid communication with a reservoir containing a fluid, the peristaltic pump comprising a two-stages linear peristaltic pump mechanisms, wherein one stage linear peristaltic pump mechanism ensures a crushed area of the tubing on which the other stage pump mechanism operate to return to its original cross sectional area and to provide a consistent flow rate of the fluid. 
     
     
         2 . A peristaltic pump as recited in the  claim 1 , wherein the two-stages linear peristaltic pump mechanism comprising a charging mechanism along the upstream portion of the tubing—a charging section of the tubing and a pumping mechanism along the downstream portion of the tubing—a pumping section of the tubing, wherein when a 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, wherein 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 comprising a charging shaft and a plurality of peristaltic charging fingers sized around the charging shaft, wherein the pumping mechanism comprising 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, wherein 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, wherein 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 , wherein further comprising a charging occluder mechanism positioned at the downstream of the charging section of the tubing. 
     
     
         6 . A peristaltic pump as recited in  claim 5 , wherein the charging occluder mechanism comprising at least one finger of the plurality of peristaltic charging fingers at the downstream of the charging section of the tubing. 
     
     
         7 . A peristaltic pump as recited in  claim 4 , wherein further comprising a pumping occluder mechanism positioned at the downstream of the pumping section of the tubing. 
     
     
         8 . A peristaltic pump as recited in  claim 7 , wherein the pumping occluder mechanism comprising at least one selected from the group consisting of at least one finger of the plurality of pumping fingers, an occluder finger at the downstream of the pumping section of the tubing, or any combination thereof. 
     
     
         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 drivers 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 connected to so said motor turn 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 turn 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, wherein said second direction is opposite said first direction. 
     
     
         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 to and turning said charging mechanism, and at least one second gear coupled with the second roller clutch in connection to 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 positioned in the contact with an outer wall of the pumping section of the tubing, wherein when the transducer indicates 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, the charging mechanism ceases operation and the pumping mechanism starts running. 
     
     
         21 . A peristaltic pump as recited in  claim 20 , wherein the transducer is a force sensing resister or a piezo electric sensor. 
     
     
         22 . A peristaltic pump as recited in  claim 3 , further comprising a rapid charging mechanism. 
     
     
         23 . A peristaltic pump as recited in  claim 22 , wherein the rapid charging mechanism comprising at least one selected from the group consisting of a sufficient short pumping shaft, sufficient fast turning rate of the charging shaft, a total surface of the plurality of peristaltic charging fingers is, which are in the contact with the charging section of the tubing, larger than that of the plurality of peristaltic pumping fingers, or any combination thereof. 
     
     
         24 . A peristaltic pump as recited in  claim 7 , further comprising a buffer mechanism positioned over the pumping occluder mechanism to prevent the pumping occluder mechanism from doing damages to the tubing and to provide compliance adjustment. 
     
     
         25 . A peristaltic pump as recited in  claim 24 , wherein the buffer mechanism comprising at least one selected from the group consisting of an occluder backer, a spring held in place by a holding member, or any combination thereof, wherein the occluder backer is made of a resilient material. 
     
     
         26 . A peristaltic pump as recited in  claim 20 , wherein two-stage linear peristaltic pump mechanism further comprising a motor processor to operate the peristaltic pump, wherein rotary positions of the charging mechanism and the pumping mechanism relative to the rotary positions of the motor shaft are prestored in the motor processor, wherein the transducer and the encoder are operatively connected with the motor processor to control the turning speed and direction of the motor. 
     
     
         27 . A peristaltic pump having a piece of tubing in a fluid communication with a reservoir containing a fluid, and a two-stage linear peristaltic pump mechanism—a charging mechanism and a pumping mechanism—to ensure a crushed area of the tubing to return to its original cross sectional area, the peristaltic pump comprising a two-stage pumping mechanism program to operate the two-stage linear peristaltic pump mechanism. 
     
     
         28 . A peristaltic pump as recited in  claim 27 , wherein the two-stage pumping mechanism program directs the charging mechanism and the pumping mechanism to act in successive series. 
     
     
         29 . A peristaltic pump as recited in  claim 28 ,
 (a) wherein the two-stage pumping mechanism program directs the charging mechanism to operate on the upstream portion of the tubing—a charging section of the tubing, after directing a pumping occluder mechanism to close the downstream portion of the tubing—a pumping section of the tubing, to fill the pumping section of the tubing;   (b) wherein when a transducer positioned in the contact with the outer wall of the pumping section of the tubing indicates that the pumping section of the tubing has been fully extended or has been filled to an extent as specified, the two-stage pumping mechanism program directs the pumping mechanism to operate on the pumping section of the tubing after directing a charging occluder mechanism to close the downstream of the charging section of the tubing to move the fluid further along; and   (c) wherein when the pumping mechanism finishes a requested pumping task indicated by the transducer, the two-stage pumping mechanism program directs the pumping occluder mechanism to close up the downstream of the pumping section of the tubing and then start the operation of the charging mechanism, and another pumping cycle starts.   
     
     
         30 . A peristaltic pump as recited in  claim 29 , wherein when the transducer detects a pressure greater than an occlusion value, the two-stage pumping mechanism program instructs the peristaltic pump to stop running. 
     
     
         31 . A method of ensuring a crushed area of a piece of tubing in a fluid communication with reservoir containing a fluid, on which a peristaltic pump presses, to return to its original cross sectional area and to provide equal volume of the fluid in each pumping cycle comprising
 (a) providing the peristaltic pump comprising two separately controlled pumping stages, a charging mechanism and a pumping mechanism, successively along the upstream portion of the tubing—a charging section of the tubing and the downstream portion of the tubing—a pumping section of the tubing;   (b) operating the charging mechanism on the charging section of the tubing to fill the pumping section of the tubing with the fluid when the pumping mechanism is not operating; and   (c) operating the pumping mechanism on the pumping section of the tubing to move the fluid further along when the charging mechanism is not operating.   
     
     
         32 . The method as recited in  claim 31 , further comprising providing at least one motor, wherein the at least one motor is connected to turn at least one from the group consisting of the charging mechanism and the pumping mechanism. 
     
     
         33 . The method as recited in  claim 32 , wherein a single motor is connected to turn both the charging mechanism and the pumping mechanism. 
     
     
         34 . The method as recited in  claim 33 , further comprising providing at least two clutches wherein said at least two clutches connected to so said motor turns said charging mechanism to operate on the charging section of the tubing when the motor rotates in a first direction while disengaging said pumping mechanism, and wherein said motor turns 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, wherein said second direction is opposite said first direction. 
     
     
         35 . The method as recited in  claim 34 , further comprising providing a transducer positioned in the contact with the outer wall of the tubing beyond the pumping section of the tubing, wherein when the transducer indicates the pumping section of the tubing has been fully filled with the fluid and has been fully extended or has been filled to an extent as specified, the charging mechanism ceases operation and the pumping mechanism starts running.