What You Should Know About the Phoenix Controls Venturi Valve

History of the Venturi Valve

Throughout history, laboratory airflow control has evolved through various approaches. Initially, the constant volume (CV) method was the standard approach. Subsequently, efficiency improvements were sought through the implementation of two-state controls, which involved reducing laboratory airflow during specific conditions, like night setback.

A more comprehensive strategy to laboratory airflow control emerged with the advent of the variable air volume (VAV) approach. In this method, sash positioning plays a crucial role in determining the airflow rate. This innovation allowed for greater adaptability and precision in regulating airflow within laboratory settings.

Another significant advancement is the employment of usage-based controls (UBC). With UBC, the airflow rate is maintained at safe minimum levels and increases only when necessary, triggered by the presence of a user at a workstation. By employing either the VAV or UBC options, both safety and energy efficiency can be optimized.

In the 1980s, Phoenix Controls made a notable contribution to the field by introducing the venturi valve, which further enhanced the capabilities of laboratory airflow control systems. Today, the combination of these approaches has led to sophisticated and efficient laboratory airflow control systems - allowing for a safer, more economical, and environmentally friendly operation.

What is a venturi valve?

A venturi valve is a variable air volume control device, but operates differently, and more efficiently, than a traditional VAV terminal box. VAV boxes utilize dampers, which use a butterfly/blade device to regulate the airflow and volume of heated or cooled air. They work with controls and sensors within an environment and receive signals that indicate when they need to change the valve’s position to adjust airflow. As a result, all VAV boxes work in tandem to adapt to their space’s airflow requirements.

One shortcoming of traditional VAV boxes is the reliance on other components within the system to maintain airflow, leading to what is known as “signal latency”. In spaces where safety requirements call for adequate ventilation, the amount of time it takes to send out and process return signals among the BAS and actuator can lead to increased exposure to hazards.

A venturi valve reimagines VAV capabilities in a modern, powerful design. The valve is characterized by its dynamic cone and spring assembly that automatically shifts backward or forward in response to air pressure changes (within a 5 percent accuracy margin), effectively regulating airflow. This cone moves parallel to the body of the valve, which consists of a constricted-neck, hourglass-shaped tube.

Due to the cone’s instant adjustment to airflow and pressure changes it can be classified as a mechanically pressure independent device. Mechanical pressure independence means that it does not require the use of sensors to prompt it with a signal for proper operation. As mentioned, this is oftentimes a drawback when operating with a VAV box, particularly in critical spaces. Phoenix Controls valves are also factory characterized, calibrated precisely to connect the cone assembly’s position on the shaft to the volume of airflow. What exactly does this mean? In a field context, it means providing correct and accurate airflow over a wider span, with no overshooting or undershooting the setpoint. Both exclusive characteristics help promote optimal environments for worker safety and integrity of results, making the venturi valve the superior choice for a variety of applications.

Watch our PAINTS Video Series to learn more about what makes the Phoenix Controls Venturi Valve unique: https://buildings.honeywell.com/us/en/brands/our-brands/phoenix-controls/resources/video-library

What is a venturi valve used for?

VAV boxes work well in some environments; for example, “In an office building, precise airflow control is not a matter of life or death, as occupants usually don’t notice the airflow variance.” However, in a lab or other crucial environment, lack of precise airflow control have detrimental effects on results, and the safety of occupants.. That’s why venturi valves are increasingly being used for labs and other critical environments.” ^[I]

In recent years, venturi valves have emerged as a necessity for maintaining optimal and safe environmental conditions in critical spaces, as well as facilities that rely on process-oriented systems. While not always a matter of life and death, having control of the airborne environment in these specialized spaces can significantly impact the integrity, output, and quality of results. This makes the use of the valve versatile - driving impact that ranges across several applications.

Below we’ll cover in more detail how venturi valves are used in critical areas including laboratory environments, healthcare spaces, and high purity manufacturing facilities.

Venturi Valve Applications

Laboratory and Research Settings

Venturi Valves have a critical presence in lab environments that require control and accuracy to produce reliable outcomes. Several elements need to be considered when assessing the needs of the space and creating a safe environment that protects occupants from fume hazards, as detailed below:

Operator Safety: Capturing and containing fumes is pivotal in ensuring safe practices for workers. This stems from a stable airflow that maintains face velocity and resilience in rapid response times.
Room Pressurization: Achieving net negative airflow is ideal for preventing contamination of spaces. This is done by employing tracking pairs, where the supply valve tracks the exhaust valve to maintain some predefined offset.
Ventilation and Comfort: To provide prompt dilution and evacuation of fumes, a minimum ventilation rate must be established first. Several factors feed into this, including air supply volume and the exhausting excess supply air via the lab control system to maintain proper pressurization.

In results-oriented environments, having a controlled and stable airflow can help translate into reliable, impactful findings. It first begins with a solution that can meet and exceed the criteria needed in maintaining a safe and comfortable facility, which Venturi Valves are equipped to take on.

For more information on our valve’s capabilities in lab spaces, visit our pages on Airflow Control in Labs and Fume Hood Safety.

Healthcare Spaces

By nature, a variety of healthcare buildings- general hospitals, urgent care, ambulatory care, outpatient clinics, medical office buildings- are easily exposed to bacterial and viral transmission and need to be equipped to contain such matters.

In fact, a driving principle of ventilation system design in healthcare settings is control of Healthcare Associated Infections, termed HAI. Surgical site infections (SSIs), a subcategory of HAIs, are reported to account for 20% of all infections and are associated to a 2-to 11-fold increase [II] in the risk of mortality according to the CDC. Consequently, extensive research and guidelines surrounding the construction of systems have been created to mitigate this. Having spaces that are properly designed to reduce this liability and promote patient healing begins with ensuring that airflow, along with contamination risk, is sufficiently controlled with the implementation of the Venturi Valve system.

Additionally, healthcare environments also house a variety of critical spaces that require both positive and negative pressure to be utilized depending on the area. For example, isolation rooms that contain infectious diseases must be maintained at a negative pressure, to prevent infectious particles from escaping, while operating rooms require positive pressure to prevent contaminants from entering the sterile space. With these interdependent relationships, venturi valves are the optimal choice for providing airflow and pressure control where lives depend on it.

Read more about how Phoenix Controls can help create healthier patient environments here.

High Purity Manufacturing

Specialized production industries such as battery manufacturing, semiconductor fabrication, and pharmaceutical production require high levels of cleanliness due to product characteristics and quality assurance guarantees. To maintain sterility, facilities must adhere to the appropriate ISO Class standards, which identify the maximum particulate concentration allowable in a space to minimize risk and ensure output is of the highest quality.

The primary way to control particulate and contamination is via the HVAC system – ensuring proper air exchange, pressurization, and temperature and humidity control. Traditionally, this is done by employing constant volume airflow control strategies, which means a constant flow of air is provided to a space, regardless of the actual conditions. It is no secret that this requires excessive amounts of energy to maintain, and results in high operational costs.

Because of this, many organizations are turning to demand-based control strategies that use air quality sensors to sense the particulate count in the room, or occupancy sensors to determine if people are present - as people, equipment, and processes are often the main source of particle generation. Then, a variable air volume device is used to adjust the airflow to a space based on the sensor readings. The Phoenix Controls venturi valve does this with accuracy and precision, while maintaining tight pressure control to prevent cross-contamination. Given that this is a demand-based approach, systems are not running 24/7, resulting in decreased energy consumption without sacrificing the cleanliness of a space.

Read more about how we help control airflow in cleanroom environments here.

^[I]Source: Surgical Site Infection (cdc.gov)

^[II]Source: https://www.facilitiesnet.com/hvac/contributed/Venturi-Valves-for-Airflow-Control-in-Labs-An-Alternative-to-VAV--41367

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