What is a Venturi Injector?
The Mazzei Venturi Injectors are small and simple. They have no moving parts and function from a pressure differential being created between the inlet and outlet of the injector body. The patented design, featuring internal mixing vanes, optimizes efficiency, suction capacity, and mixing capabilities.
The Mazzei injector is easy to install in new or existing irrigation systems. Often these are installed inline and sufficient pressure differential is achieved. If not, a simple bypass line can be used and a pressure reducing valve can be installed between the inlet/outlet for achieving better suction. In a low pressure water system a booster pump might be used to increase water pressure allowing for better pressure differential. In almost any application a Mazzei Venturi Injector is a great cost effective solution for fertigation or chemigation.
Manufactured in a variety of materials for non or low acid additives or for harsher chemicals.
Mazzei Polypropylene Injectors
How does the Mazzei Venturi Injector work?
Pressurized water enters the inlet and the Venturi design constricts the flow and creates a higher velocity stream of water. The high velocity actually decreases the pressure creating a vacuum that draws the additive through the suction port, mixing it into the water stream.
As the constricted area in the Venturi widens back out, the velocity is reduced and the mixture flows with reduced energy than when it entered the injector Venturi.
If you want to see it in action, here are some animated videos of the operation. Please click these video links:
How a Mazzei Venturi Injector Works
Fertilize through Drip Irrigation with Venturi Injectors
Mazzei venturi injectors operate over a wide range of pressures and only require a small pressure differential between the inlet and outlet. We highly recommend using Mazzei’s free Injector Selector Tool to assist in choosing the best model for your injection needs. You can create an account right on their website and it will store all the information and recommendations for several scenarios.
You will need some specific information about your system and your additive(s) to input into the Selector Tool.
Total Flow in GPM (gallons per minute) - Flow volume the system will use.
Suction in GPH (gallons per hour) - How much solution you want to inject.
Elevation - Feet above sea level at injector location.
Liquid Weight of additive(s) in pounds per gallon.
Injector Position in feet - Where will the injector be in relation to liquid being injected? Above, Below, Same Level
Upstream Pressure (PSI) - Inlet pressure before any pressure reducing valve(s).
Downstream pressure (PSI) - Pressure after any pressure reducing valve(s).
Pressure Regulator - Manual (ex. ball valve) or Automatic (Pressure Regulator or Pressure Reducing Valve).
Once this information is entered into the Injector Selector Tool, it will calculate the information given and recommend one or more model options. Should you need further assistance please reach out to Mazzei for tech support. See the contact information at the end of this article.
Another method is using the Mazzei Performance Tables. To use the tables you must understand what the four columns mean.
The first column is the pressure at the inlet or upstream of the injector.
The second column is the outlet or downstream pressure.
The third column is the “motive flow”, which is how much water must flow through the injector to maintain suction.
The fourth column is the suction rate. This would be aligned with the outlet pressure.
An additional number noted in blue print is the zero suction point. This happens when the outlet pressure no longer has sufficient pressure differential to create suction.
Please note that some measures are noted in GPM (gallons per minute) and others in GPH (gallons per hour).
Use this link so you can actually see the details of the injectors by model number: Mazzei Injector Performance Data.
Click here to view the Guide to Injector Performance Tables.
Another great video from Mazzei - Chemical Fertilizer Application with Mazzei® Venturi Injectors - ENG
Installation of the Mazzei Venturi Injector
The injector can be installed directly inline as long as there is sufficient pressure differential between the injector inlet and the injector outlet to create the required suction. If not, it is recommended to install the injector on a bypass line with a pressure reducing valve in the mainline to create sufficient pressure differential. On the off chance that your inlet pressure is very low, a booster pump can be used to increase the pressure on the inlet side of the injector.
See the illustrations below for examples.
Inline Installation can be used when all the mainline water will be the injector’s motive flow. You will need to match the injector’s flow and pressure to your system‘s operating requirements. The injector acts as the restriction that creates the pressure differential which then creates suction of the additive.
Bypass Installation w/Manual Valve would use a bypass line for the injector installation and a manual ball valve on the mainline. This allows you to fine tune the pressure differential by adjusting the valve to create optimal pressure reduction to create the required suction. The bypassed water draws in the additive and the mixture is then reintroduced into the mainline water flow.
Bypass Installation w/Pressure Reducing Valve is the same as with a manual valve but the pressure reducing valve is set to control the pressure as needed by opening and closing the valve hydraulically as the pressure fluctuates.
Booster Pump Installation would be used if the inlet pressure is too low to achieve the desired pressure differential for proper suctioning of the additive. The booster pump would be installed on a bypass line followed by the injector. The mixture of bypass water and additive would then be reintroduced back into the mainline water flow.
Additional Installation Tips can be found here.
Important
Any time chemicals are injected into irrigation water that is a shared water source, backflow protection is required. This would include municipal water systems, drilled wells, and surface water sources such as ponds or streams. Please research this with your local authorities as environmental regulations vary with every district.
Assistance Needed?
If at any time you feel overwhelmed with trying to make your selection, the folks at Mazzei are extremely helpful and will work with you to make the optimal selection for your system. If we do not carry the model you need we are happy to work with you and Mazzei to get what you need. Please reach out to our wonderful Drip Depot Customer Support staff for assistance. Or you can contact Mazzei directly for assistance.
Mazzei Customer Technical Support:
500 Rooster Dr.
Bakersfield, CA 93307
661-363-6500
Email : info@mazzei.net
Mazzei’s website offers all kinds of helpful information not only for selecting the right injector, but for installing, troubleshooting, and technical info.
Knowledge Center - Irrigation and Air Injection
Installation and Troubleshooting