1. Phoenix Accel II Venturi Valve 101
+/- 5% of Signal/Position 192 / 48 Pt.
NIST Flow Characterization
Accuracy, Safety, Repeatability, Reliability
Protection by maintaining correct airflows.
Critical areas require volumetric offset to assure pressurization.
10% of total exhaust room offset requires accurate airflow control.
Maintains a constant volume offset in VAV and CVV applications.
Total Supply + Offset = Total Exhaust
Maintains neg/pos airflow and constant offset with doors open.
Exiting/entering velocity through door decreases when door is opened.
Correct flow and pressurization with filter load.
Correct flow and pressurization regardless of duct design.

2. Pressure Independence
Cone Performs Pressure Compensation
500 Pa
625 Pa
750 Pa
750 Pa
375 Pa
500 Pa
625 Pa
375 Pa
250 Pa
125 Pa
250 Pa
Some venturi valves measure flow for control, while others, like the Theris valve, use the flow metering approach.
When there is low static pressure, less force is applied to the cone, which causes the spring inside to expand and pull the cone away from the venturi. As static pressure increases force on the cone such as in filter loading, the spring compresses and the venturi cone moves reducing the open area to compensate for the pressure change.
Cone square function, spring square function for flow and pressure, spring clips on either side of the spring prevent the spring from over extending or compressing.
.3 to 3.0 in w.c. pressure independence
+/- 5% signal whereas boxes are to flow range
Speed of response— Theris valves respond to airflow changes in less than one second without the aid of flow measurement devices. This performance is unmatched by any valve with flow measurement, because these devices need more time to react to airflow changes.
Because there are no pressure or velocity sensors, we do not need continuous fine tuning or calibration. Additionally our air metering device is not susceptible to clogging from excessive lint.
Theirs VV also compensates for HEPA load.
Pressure response delays and measurement inaccuracies due to flow cross contamination such as those that occur with VAV Boxes can affect the room’s containment and compromise stability and safety.
Accuracy +/- 5% signal, full flow range
192 pt calibration to 48 pt lookup table
Maintains safe & constant flow

3. Factory Characterization Factory Characterization
Immediate and Accurate Flow Tracking
In order to meter flow, every Theris valve must be characterized in the airstream of our manufacturing air stations. We have millions of dollars invested in air stations that go way beyond NIST traceable. We have six air stations like this and every valve that leaves our factory is characterized.
This process uses multiple NIST traceable devices, resulting in an error rate of typically less than 2% for a flow range of CFM.
Venturi fixture assemblies sent to Colorado Engineering Experiment Station Inc. (ceesi.com)
NIST references and multiple NIST devices used to deliver the highest degree of accuracy.
We go above and beyond the minimum requirements for NIST traceability.
In addition, each product line has been life-cycle tested for 20 years of trouble-free operation.
Additionally our factory is certified ISO 9001