Venturi 4091

Black Kynar (PVDF) Mazzei Venturi injector for ozone injection into water.  Model 4091, for water flows from 150 to 530 GPM.

1 week lead time from the manufacturer

Model 4091 Venturi Injector uses 4" Male NPT connections inlet and outlet. Venturi is made from Black Kynar (Polyvinylidene Fluoride) material for maximum ozone resistance resulting in longevity on all ozone systems.  For other materials, including stainless steel please contact us.

The Mazzei venturi injector is the most widely used method of dissolving ozone gas into water, and, for good reason.  This is the most efficient and simple method to get ozone gas to dissolved into water.

 Most ozone injection systems will use a Mazzei venturi to dissolve ozone into water.  If you are replacing a venturi injector check the center of the bottom of the venturi (below the suction port) for a part number.  It will be 3 or 4 numbers long.  If you cannot find this, or if you are building your own system and need help sizing a venturi, please give us a call.

Venturi Injectors use a pressure differential of the water to pull ozone gas into the water.  Using internal mixing vanes, water and gas are further mixed in the outlet of the venturi. 


How a Venturi Injector Works

Click HERE to see a video on how the venturi injector works

A venturi injector pulls ozone/oxygen gas into the water stream under a vacuum and dissolves that ozone/oxygen gas into water very efficiently.  A pressure differential across the orifice in the venturi creates a high-velocity jet stream of water.  This high velocity of water results in a decrease in absolute pressure and creates a vacuum on the third leg, or gas suction let.  This gas is quickly and efficiently dissolved into the water directly after this venturi.


Ozone/Oxygen gas is pulled into the water.  The gas fills the void created by the suction action of the venturi to entrain the gas bubbles into water very efficiently.

 Venturi injector in action



Venturi Injector Performance

A venturi injector will operate over a wide range of pressures and water flows, however, each ozone injection application should be evaluated to ensure the right injector is chosen for your specific application.  Below is a performance chart for air/ozone suction into water based on water flow and pressure on the venturi.

Click HERE for complete Mazzei Venturi Injector Performance Tables (all mazzei venturi's are in one table)

Mazzei Venturi performance Chart


For questions on how to size the right venturi injector for your specific application call our application engineers.  We would be glad to help.


Diagram of Mazzei Venturi Injector Parts

Model 4091 Venturi Injector

 The Mazzei Venturi Injector is sold with an integrated check valve assembly.  The parts used are all ozone resistant and will hold up to both ozone and hydrogen peroxide injection into water quite well.  There is a barbed connection on the end of the check valve assembly to connect tubing to.  Also, there is a threaded section that can be used for a threaded connection by cutting the barb off the fitting.  This is a great option for a more leak proof connection.


Tech Tip:

When we install venturi's on systems we remove the entire check valve assembly and thread a stainless steel check valve directly to the threaded body of the venturi.  This eliminates the entire check valve assembly provided by Mazzei.  We have found these to be failure prone, along with a light duty plastic threaded connection that can leak over time.  By using a stainless check valve both potential ozone leaks, and back flow to your ozone generator are prevented.


Mazzei Venturi Injector Dimensions

Model 4091 Venturi Injector


Check Valve:

The larger Mazzei venturi's (2" and larger) are provided with an open port.  A check valve should be placed on this port to ensure there is no back-flow of water into your ozone generator.  

Click HERE for Mazzei's recommendations on supplemental check valvesCheck valve used on venturi


By-Pass Assembly:

Installing the venturi injector into a by-pass assembly is suggested in some applications.  When total flow rates of water are greater than the venturi chosen can handle a by-pass may be required.  Also, if the specific suction and water flows are unknown the by-pass will allow for some flexibility in the venturi operation.  See image below for details on a by-pass assembly.

Click HERE for By-Pass Installation bulliten

If required a by-pass assembly can be provided with your venturi purchase.

OZone venturi in by-pass asembly


Mazzei Injector with By-Pass Assembly for applications where total water flow are greater than the venturi can handle


Ozone Solubility Information:

    -O3 Solubility in Water

    -Fundamentals of Ozone Solubility

    -O3 Dosage vs. O3 Dissolved

    -Compare Venturi to Diffusers

    -Bubble Diffuser to Dissolve O3

    -Venturi Injector to Dissolve O3

    -Static Mixer to Dissolve O3

    -How to Read Venturi Charts


Tech Notes:

    -Complete Mazzei Venturi Injector Performance Tables (all mazzei venturi's are in one table)

    -Tech Note - Injector Troubleshooting Guide

    -Tech Note - Injector Ozone to Water Mixing

    -Tech Note - Correction Factor for Gas Flow When Gas is Under Pressure

    -Tech Note - Injector by-Pass Assembly

    -Tech Note - Supplemental Check Valves

    -Tech Note - Handling Solids During Injector and Nozzle Mixing 

    -Tech Note - Installation Notes

    -Tech Note - Pressurized Sprinkler Applications

    -Tech Note - Pressurized Water Line Applications

    -Tech Note - Removal of Hydrogen Sulfide by Aeration

    -Tech Note - Removal of Iron and Manganese by Aeration

    -Tech Note - Water-Well/Pressure Tank Applications


More Information
Manufacturer Mazzei
Call For Price No
Typical Water Flow 150 to 530 GPM
Thread Size 4" Male NPT
Max Pressure 150 PSI
Material of construction Black Kynar
Lead Time 1-week
Dimensions (LxWxH) 11-inches long x 1.9-inches wide x 4.5-inches tall
Country of Origin USA
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