Where the RXMD differs from other peristaltic pumps is the ability to produce high pressures — far higher than the 30 psi maximum of typical peristaltic pumps. Standard RXMD models are rated up to 90 psi, and custom configurations can achieve up to 130 psi. At high pressures, predictability and control is essential, and the RXMD can be tuned to meet a specific flow profile. For example, in RF ablation cooling, the pump must produce consistent flow at a high target pressure, but the flow must drop away once that target pressure is met. Figure 3 shows this performance with pumps set for three different target pressures. The figure shows the predictable “knee” shape of the graphs, which describes the flow profile.

What allows this extreme pressure performance and control is a robust track mechanism supported by two heavy duty coil springs. In addition, a new factory adjustment mechanism enables the pressure and flow profile to be tuned.

Other enhancements include a larger opening for tube loading and a new tube holder that ensures rapid, trouble-free tube loading and minimizes the risk of human error. The sprung dual holder design grabs the tube firmly and effectively without creating flow restrictions. The tube holder’s 90 angle centers the tube in the holder for optimal performance every time the safety cover is closed. The tube holder’s coil springs compensate for variations in tube dimensions and shore hardness within allowable tolerances.

Support beyond the Product

A purpose-designed off-the-shelf pump is a good start, but it is not sufficient to provide an effective solution. A company designing a new medical device must work with a supplier experienced with OEM medical device applications — one that will give access to their engineering staff and take the time to understand the unique requirements of the customer’s application. The customer/supplier team will work on designing custom configurations, testing them, and agreeing to a written specification. The end result of this process is an optimal pump solution that meets the customer’s precise flow and pressure requirements.

It is equally important that the supplier has strong quality systems in place, giving product traceability and change control. The product must meet the requirements — exactly — with the first order, and with orders placed years into the future.

RF ablation is an important technique in medical procedures that helps improve the lives of patients. For systems that require cooling or temperature control, the proven and enhanced RXMD peristaltic pump is ideally suited to these applications.

This article was written by Rodd Turnquist, Sales Manager OEM Division, and Christian Skantze, Product Manager, at Watson-Marlow Fluid Technologies Group, Wilmington, MA. For more information, click here .