System, method, and apparatus for infusing fluid
A peristaltic pump, and related system method are provided. The peristaltic pump includes a cam shaft, first and second pinch-valve cams, first and second pinch-valve cam followers, a plunger cam, a plunger-cam follower, a tube receiver, and a spring-biased plunger. The first and second pinch-valve cams are coupled to the cam shaft. The first and second pinch-valve cam followers each engage the first and second pinch-valve cams, respectively. The plunger cam is coupled to the cam shaft. The plunger-cam follower engages the plunger cam. The tube receiver is configured to receive a tube. The spring-biased plunger is coupled to the plunger-cam follower such that the expansion of the plunger cam along a radial angle intersecting the plunger-cam follower as the cam shaft rotates pushes the plunger cam follower towards the plunger and thereby disengages the spring-biased plunger from the tube. A spring coupled to the spring-biased plunger biases the spring-biased plunger to apply the crushing force to the tube.
1. A peristaltic pump, comprising:
a cam shaft;
first and second pinch-valve cams coupled to the cam shaft;
first and second pinch-valve cam followers configured to engage the first and second pinch-valve cams;
a plunger cam coupled to the cam shaft;
a plunger-cam follower configured to engage the plunger cam;
a tube receiver configured to receive a tube;
a spring-biased plunger coupled to the plunger-cam follower, wherein:
the plunger cam engages with the plunger-cam follower such that as the plunger-cam follower is actuated away from a center axis of the cam shaft via the plunger cam, the spring biased plunger actuates away from the tube receiver and the tube,
the plunger cam follower is configured to disengage from the plunger cam, and
a spring coupled to the spring-biased plunger biases the spring-biased plunger to apply a crushing force to the tube;
a position sensor operatively coupled to the spring-biased plunger configured to determine a position of the spring-biased plunger when the plunger-cam follower is disengaged from the plunger cam and the spring applies the crushing force from the spring-biased plunger against the tube; and
a processor coupled to the position sensor, wherein the processor is configured to estimate fluid flow utilizing the position of the spring-biased plunger as indicated by the position sensor when the plunger-cam follower is disengaged from the plunger cam and the spring applies the crushing force from the spring-biased plunger against the tube.
2. The peristaltic pump according to claim 1 , further comprising an angle sensor operatively coupled to the cam shaft configured to determine an angle of rotation of the cam shaft.
3. The peristaltic pump according to claim 1 , wherein the processor compares a first static region of the position sensor to a second static region of the position sensor to estimate the fluid flow.
4. The peristaltic pump according to claim 3 , wherein the processor determines the first static region by identifying the first static region within a predetermined range of angles as indicated by an angle sensor.
5. The peristaltic pump according to claim 4 , wherein the processor determines the second static region by identifying the second static region within a second predetermined range of angles as indicated by the angle sensor.
6. The peristaltic pump according to claim 3 , wherein the processor determines the first and second static regions by measuring position sensor at predetermined angles as indicated by the angle sensor.
7. The peristaltic pump according to claim 1 , wherein the processor compares a first static region measured by the position sensor to a second static region measured by the position sensor to estimate the fluid flow.
8. The peristaltic pump according to claim 6 , wherein the processor determines the first static region by identifying a peak movement of the spring-biased plunger as measured by the position sensor and identifies the second static region to be after the identified peak.
9. The peristaltic pump according to claim 6 , wherein the processor determines the second static region by identifying an end of the first static region.
10. The peristaltic pump according to claim 1 , further comprising:
a balancer cam;
a balancer-cam follower; and
a balancer spring configured to apply a force against the balancer-cam follower and thereby apply a force from the balancer-cam follower to the balancer cam,
wherein the balancer cam is shaped to reduce a peak torque of the cam shaft as the cam shaft rotates around its axis of rotation.
11. The peristaltic pump according to claim 1 , further comprising an electric motor operatively coupled to the cam shaft to apply a rotational torque to the cam shaft.
12. The peristaltic pump according to claim 11 , wherein the electric motor is one of a stepper motor, a DC motor, a brushless DC motor, a brushed DC motor, an AC motor, a polyphase induction motor, an electric motor with at least one permanent magnet coupled to a stator or a rotor, and an induction motor.