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FAQ: What is the SuperPump pressure limit?

The SuperPump pressure limit will depend on several variables, such as the beat rate, stroke volume and pressure profile generated by the system.  As a guideline, refer to the plot below showing the pressure limits of the SuperPump AR based on a 50% sine wave with pressure loading centered on 0mmHg (i.e. the pump generating both positive and negative peak pressures each cycle).  Actual peak pressures that the system can produce will vary depending on application.

Will I damage the SuperPump AR if I operate it past the pressure limits?

No.  The SuperPump AR motor controller uses a current limit to prevent any damage to the motor or actuator.  If the system is over-pressurized, the current output to the motor will be regulated resulting in the stroke volume being limited.

How do I know if I have reached the pressure limit of the SuperPump?

There are two ways to determine if the pressure limit is reached.  This will depend on whether the SuperPump has reached the instantaneous current limit, or the continuous current limit.

• If the instantaneous current limit is reached, the Stroke Volume [mL/stroke] displayed on the Controller screen will stop increasing even though the percent gain [% Gain] value continues to increase while turning the Amplitude knob.
• If the continuous current limit is reached, the Stroke Volume [mL/stroke] displayed on the Controller screen will begin to drop after a short period of operation. This will be accompanied with a noticeable drop in peak pressure as well as a ‘clipping’ of the peaks of the dl/dt signal from the Controller.

How can I prevent reaching the current limit?

To prevent reaching the current limit when using a SuperPump AR, unnecessary pressure drops should be avoided in the flow loop.  This would include:

• Avoid using excessively small tubing in the flow loop. Minimum ½” ID tubing is recommended.
• Avoid unnecessary joints in tubing, such as reducers, tees, and elbows. If possible, place them after the point of pressure measurement in the flow loop.
• Ensure there is sufficient compliance, and/or a reservoir in the flow loop to accommodate the volume displacement of the SuperPump piston’s stroke volume.

If it is suspected that the current/pressure limit is being reached, it is recommended to monitor the pressure being generated at the outlet of the piston.  This will help establish whether the system is being operated near conditions shown on the graph above.