Pressure Pulse Generator

This device can be used to measure the dynamic performance of nozzles, orifices, check valves and flow meters. It also could be used to measure the dynamic compliance of hydraulic systems. It can supply accurate pressure and flow waveforms which duplicate those found in coronary arteries and the aorta.

The device uses a electromechanical actuator to control the fluid pressure inside a cylinder which is used to pressurize the fluid delivered to a nozzle or other fluid system component. The displacement of the piston and the pressure of the fluid are measured during the pressure pulse. The pressure is controlled by a feedback control system which maintains the proper power to the actuator. The time at a particular pressure is limited. This keeps the actuator from overheating, but it reduces the time that the maximum pressure can be sustained. A typical 200 psi pressure pulse can last up to 20 msec and the device can maintain 120 psi for about 100 msec. A model designed to provide 200 mmHg (3psi) Pressure pulses can run continuously. A modified version of the device can provide pressure/flow pulses of any given time.

A pressure versus time wave form may be created using the program or one can be read from data file. Also, the device can be used to measure the discharge coefficient of a nozzle etc.

The device is controlled by a PC based computer program. The program controls the power applied to the actuator and measures the pressure applied to the pump and the displacement of the piston. The program also plots the pressure versus time data from the test on the screen. The programmed pressure is also plotted. In addition the program allows the operator to save the data to a file which may be loaded into a spread sheet program for plotting and analysis.

Shown below is a system that is used to test catheter based pressure sensors.

We have buit systems to test nozzles, flowmeters, simulated arteries and pressure sensors.

Specifications for a typical system designed to test nozzles:

• Using water or alcohol as working fluid.(can use air as well)
• Maximum output pressure: 200 psi (higher pressures are available)
• Maximum delivered volume 1.0 cc @ 100psi 0.5 cc @ 140psi
• Maximum pressure pulse duration: 100 msec @ 100psi 50 msec @ 140 psi
• Rise time (to within 10% of input pressure) 2 msec
• Settling time (to within 3% of input pressure) 6 msec
• Pressure accuracy (1/2 sine wave 5 Hz) +/-(1.5%+1 psi)
• Materials in contact with fluid: Brass, Stainless Steel, Delrin, Buna-N and Tygon tubing(Low pressure circuits only)
• Note that the pressure and/or the volume can be increased for additional cost.