The Ventilator Control Unit works on the flow-time principle. An inspiratory airflow is delivered to the animal for a known time resulting in a known air volume. This approach provides great flexibility. A wide range of volumes, breaths/minute and Inspiration/Expiration ratios are possible without additional hardware and using just three controls: respiration rate, percent inspiration and flow rate.

The MR-compatible Valve Assembly incorporates two high speed, miniature pneumatically activated, non-metallic valves to direct air between the animal and vent ports. Locating the valves close to the animal in the magnet bore improves performance by minimizing dead space and tubing compliance.

The MR-compatible Valve Assembly allows inspiratory air or anesthetic gas to be delivered to the animal during inspiration. During expiration, the valves switch to vent the inspiratory airflow and to allow the lungs to vent passively to the atmosphere. The valves allow inspiratory air to flow continuously preventing pressure transients that would result from starting and stopping the flow of air.