A tubing pump is a simple yet efficient pump design which relies on a sequential constriction of a length of flexible tubing to move fluids through a process of positive displacement. There are two basic forms of these devices, namely rotary and linear, both of which achieve the same result by restricting the tubing in different ways. Tubing pumps are particularly effective at pumping sterile or dangerous fluids where the liquid needs to be completely isolated from the surrounding environment and vice versa. The tubing pump, or peristaltic pump as it is also known, is suitable for pumping low or high viscosity fluids, and is commonly used in the chemical, medical, and cleaning industries where high flow rates are not required.
A rotary tubing pumps consists of a length of flexible tubing with one end connected to a fluid reservoir and the other forming the pump's discharge point. The pump mechanism consists of a circular casing with a lobed rotor in the center fitted with round wheels or shoes on the end of each lobe. The tubing is placed around one half of the casing in such a way that the lobe wheels press against and constrict it as they pass that half of the casing. As this happens, positive displacement forces fluid in the tube ahead of the constricted point to flow along the tube in the direction the rotor is turning. At the same time, the tube returning to its open state as the rotor shoe passes draws more fluid into the pipe to be moved forward in turn by the next passing shoe.
The less common linear type of tubing pump features a similar tube reservoir and discharge arrangement as the rotary pump with the tube laid out flat in a straight line. A number of flat plates stacked against one another are positioned just above the tube. Each plate has an identical profiled hole in its upper half with all the holes lining up with each other. A sequential cam is passed through these holes which, when rotated, causes the plates to move up and down, constricting the tube sequentially. This pulsing constriction of the tube moves fluid through the system via the same positive displacement principle seen in the rotary tubing pump.
The tubing pump is an ideal system for pumping fluids of varying viscosities at moderate rates and with highly predictable discharge values. The closed circuit design of the pump makes it ideal for moving sterile or hazardous fluids where any cross-contamination between the fluid and environment is unacceptable. These features make this pump system a good choice for certain chemical processes and for pumping intravenous fluids or drugs into infusion systems. Tube pumps are also frequently used in cleaning systems where they are utilized as dosing mechanisms for detergents and water softeners.
