There are many ways to integrate fertilizer substances or products into the irrigation water to protect the crop. We recently told you about fertilizer pumps, in which we explained that you could introduce fertilizers and other products and that there were different types of them. Today we want to introduce you to the Venturi injector system that offers different advantages, all very interesting, which should be known in depth.
Table of Contents
What is a Venturi injector?
This system works over a wide range of pressures and only requires a minimum pressure differential between the inlet and outlet ends to initiate emptying at the suction port.
This, together with its high efficiency and the affordable price at which it can be purchased, makes this system highly recommended for urban gardens and other types of crops. It should also be noted that this system does not require any electrical connection, which is a great advantage. On the other hand, it is quite safe because it works with the vacuum that the pressures create inside.
How does the Venturi injector work?
The operation of Venturi, although simple, is quite particular. This device is made up of two funnels that are joined at their narrowest part. The water, when passing through what we can identify as the throat, increases its speed causing a negative pressure that is used to inject the desired solution.
Explained in a more detailed way, what happens in the Venturi system is that a contraction of the system inlet is caused by the passage of pressurized water that causes a high speed jet to form. This increase in speed through the injection chamber generates a decrease in absolute pressure creating a vacuum and causing the substance to be drawn towards the suction port where it mixes with the water.
What is important to keep in mind is that Venturi works by sucking or aspirating the solution, be it a nutrient, a fertilizer, a pest or disease control product; so that it mixes with the water in the pipe. It could not work if it were not through this change in pressures, although it must be remembered that it is the vacuum that finally achieves the expected effect.
How to use venturi?
The injector starts working when the auxiliary valve that has been installed in the suction hose opens. To achieve that the suction effect is generated, we must partially close the valve that regulates the pressure of the main line until the device's own flow has been generated. If we tried to close the valve after this point, the pressure in the irrigation system would decrease. If what we want is for the system to end, it is only necessary to fully open the pressure regulating valve and close the auxiliary valve.
You can see our injectors here
Do you have any doubt? Ask us.
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Hi, good morning
I contact you because I have an installation with a venturi to introduce ozone into the water
But after a while the venturi stops working and does not suck
I turn off the installation for a little while, I turn it on again, it works fine for a while but again it does not suck
What can this be due to?
Good,
We are sorry but we have no experience of installing Venturis for ozone aspiration directly.
But it is possible that ozone generates a problem at the mixing point between water and gas since ozone is a powerful oxidant and generates some type of residue that obstructs the gas inlet.
Sincerely,
The Mundoriego team.
Good morning, the same thing happens to me, but I'm injecting fertilizer. The point is that the pressures equalize after a while and it stops working. I have tried to close and open the keys but the output ends up getting the same pressure as the input
Good,
The problem is due to pressures, the venturi must be installed parallel to the motive pipe making a bridge, in the motive pipe in the middle of the bridge a valve must be installed that guarantees a constant pressure difference between the inlet to the venturi and the outlet to the venturi, if the flow rates vary, it is advisable to install a pressure reducing valve to guarantee the pressure difference.
If the inlet and outlet pressure of the venturi are equalized the venturi will have no potential energy to cause suction.
Sincerely,
The Mundoriego team.
Goodnight.
My question is the following. I have an irrigation pump that begs me with three sprinklers. And I would like to put an injector on it. I don't know if one for all three or one for each sprinkler. But I do not know how I have to calculate the diameters of the tubes.
Good morning,
In the article you can download the technical sheet of the venturi and check the flow and pressure difference requirements for its correct operation:
https://mundoriego.es/producto/inyector-venturi-pp-34/
Sincerely,
The Mundoriego team.
Good evening, what does the self-priming ability on the Venturi injectors mean?
Self-priming capacity: 34-279L / h
If it refers to the flow, it is the amount to be paid in liters / hour.
hello I would like to put a venturi injector, I have the irrigation by exudating tape
that feeds from a 5000L cistern raised 1 meter from the ground, could it work?
If it will work, which model would be the most recommended?
kind regards
For a venturi injector to work, it needs a pressure much greater than 1 mwc (0.1 bar).
You need a pressure before the venturi inlet twice that of the outlet.
If you need 1 bar of pressure to irrigate, you will need the venturi to receive 2 bar, 20 mwc
The venturi system for fertilizer injection is placed before the filter or after the filter?
The filter must go before the venturi injector, so that the water reaches the dosage with the fertilizer as clean as possible.
Well I have a question for it to work well the venturi must have a half inch inlet or it must have 1 inch.
I have the problem if I open the 1-inch key, it works well, but if I open the half-inch key, it does not absorb, why is it?
Good,
The Venturi needs a minimum of flow and pressure to operate, possibly the flow supplied by the ½ ”valve is not sufficient to operate the Venturi.
Sincerely,
The Mundoriego team.
Hello! How could I get the air suction flow in a venturi to aerate a basin?
With a pump of about 20 m3 / h and 15 mca
Thank you!
With the performance table of the Mazzei venturis you can estimate the air suction flow, but there is no statistical data on the measurement you require.
We do not have air meters or air flow meter.
I would like to know, if I have automation knowledge but have never done an irrigation, where should I start? I want to plant a vegetable
We advise you to go to an agricultural technician or local installation company where they have professionals for advice, depending on the type of vegetable and terrain.
We cannot provide this service online, it is advisable in person in the field.
GOOD MORNING I HAVE A 120LH BELLY BUT I JUST GET IT SUCK ME ABOUT 60LH
COULD YOU EXPLAIN TO ME WHAT IT IS DEVICED?
AND THAT I HAVE TO ACHIEVE TO RAISE THE FLOW RATE.
THE DIFFERENTIAL IS 2K.
THANK YOU.
Good Morning.
With that differential it should work fine, provided it is properly installed. Tell us your customer name, and we will see the venturi model that we have sent you.
For the venturi to work well there can be no back pressure from the drippers by installing a buffer tank or can this be avoided?
For a venturi injector to function properly it must meet the requirements according to the operating table, that is, there must be a difference between the pressure before the venturi and after the venturi. From experience it works well when the pressure difference is at a 2: 1 ratio. For example, if you have 3atm at the venturi inlet you must have 1.5atm at the venturi outlet. Another point to take into account is that the flow indicated in the table, 500, 1000, 3000, etc., must pass through the venturi. depending on the flow to be sucked.
Hello, good morning I have a venturi and when I disassembled it I lost the molle and the ball. The thing is kea now I have it but I do not know the order to mount it. I mean the ball goes first or the molle. Thank you.
Good,
We need to know the Venturi model that you tell us to be able to tell you.
Sincerely,
The Mundoriego team.
Hello, good night, I have a venturi installed and it only sucks me at the beginning of connecting, for and as if it will equalize pressures, I have the bypas made with the same section of pipe as the general one and output to drippers, will it be a problem.
Thank you
A greeting.
Good morning,
That the section is the same there is no problem, the problem comes because the pressure of entry to the venturi and exit from the venturi cannot be the same. It has to generate a pressure difference and enough flow must pass to generate the suction effect, as indicated in the manufacturer's table.
Sincerely,
The Mundoriego team.
Good morning, I have a 1" venturi and the motor outlet pipe is 1" the same, the motor is also 1". But it does not suck.
Good morning,
For the Venturi effect to occur, a minimum pressure difference of 1 bar must be generated between the inlet and outlet of the venturi. If you already have it, check that you have enough irrigation flow for it to work properly.
You can consult the technical data sheet of your venturi to know the minimum and maximum irrigation flow that you must have. We attach the link for the assembly of a Venturi system, so you can check if there is an error in the installation.
https://youtu.be/kkICYepDt_w
Sincerely, the Mundoriego Team.
What system can I do to fertilize with drip irrigation with a 20000-liter tank 3 meters high? I don't think it has enough pressure for the venturi, what system do you recommend?
Good afternoon,
For drip irrigation you need a pressure of at least 1 bar (10 mca), if you do not have it, you can install a pumping equipment.
As for the Venturi system, if you cannot provide the pressure you need, you can use a fertilizer spreader, since these equipments do not require pressure for their operation.
Greetings.
Y'a-t- il une position idéale par rapport de l'injecteur venturi par rapport à la ligne principale pour que ça fonctionne?
The venturi injector is generally installed in a bypass system, in a vertical position. You can see its operation and installation in the following videos on our website: How to mount a Venturi injector? Installation of a Venturi system fertigation equipment . A greeting.
Hello, good morning, I have a drip irrigation installation with a 50 mm main pipe. I installed a venturi with a 32 mm pipe. the fact is that there is no way for it to work, obviously I must do something wrong, but I don't know what it is,
The pump gives me a pressure of 5 Kgs, so it is more than enough and even if the valve in the main tube is completely closed, it does not give me the pressure differential at the outlet.
You should install such a non-return valve at the outlet of the main valve.
Thank you in advance
all the best
juan miguel
For the proper functioning of a Venturi system, you must take into account the pressure difference that is generated in the bypass, and the minimum and maximum irrigation flow that derives from the Venturi system and that is determined by the manufacturer.
If your installation has enough pressure to generate the pressure difference that the Venturi needs, you should check the flow with which you are working and compare it with that of the technical sheet to find out if it is adequate.
Sincerely, the Mundoriego team.
Good afternoon, I have a private garden of about 150 m2, I have it installed with tape drippers, these hold 1,2 bars of pressure, I had to mount a pressure reducer without a valve that drops to those pressures, the fact is that I install the venturi and it doesn't suck, the water comes from a well with a pump and I don't know exactly how much pressure I'll put in but it must be enough since the tape drippers were literally split in half, what's more, when reading that for the venturi to work there must be some pressure I decided to install a reducer at 2 bars, it still did not work and the drippers did not break but ended up being damaged, from what I have read there must be a specific pressure difference for it to work, not knowing how much pressure I have in the water from the well, which I estimate will be more than 4 bars.
Do you know if by installing a pressure reducer but with a valve, that oscillates between pressure, you can play with it until you find the appropriate difference between inlet and outlet and get said venturi to work.
Thanks in advance.
A greeting.
Hello, according to what you told us, the problem you may be having is that you are not supplying enough flow for the venturi to work.
We advise you to consult the technical data sheet of the venturi model you have and check that it works with the correct flow rate.
If it does, then you must regulate the inlet and outlet pressure using the general pipe key, until you reach the pressure difference indicated on the technical sheet.
You can install the pressure reducer before the venturi and regulate the pressure until you get the right difference in your venturi system and give you the difference you need for your irrigation system.
If you still need another pressure reducer, install it after the venturi system to get to the one that needs the irrigation tape.
Sincerely, the Mundoriego team.
Good morning, Almudena.
I already have the technical sheet of the venturi, I detail the data:
Flow range: 0,81 - 0,29 m3/h
Working pressure: 0,7 - 9,5 bar
Self-priming capacity: 3 - 37L/h
I have already installed a pressure reducer, I have 5 bar of pressure in the water coming from the well, I have put this before the venturi, then I have installed a fixed pressure reducer (it cannot be varied) at 1,2 bar of pressure , installed before the programmer, for the water that reaches the irrigation tape to go to the pressure that it needs.
I've been playing with the pressure reducer to see if lowering it would find the exact difference to start sucking, because nothing doesn't work.
The only way I have managed to make it work is with the maximum pressure of the well water, I completely close the venturi valve that closes the main pipe, because later I have a tap, if I open it completely the venturi sucks perfectly, but Of course, it is throwing the water on the ground, and I cannot take it with that pressure to the garden because the irrigation hoses burst, it is a bit confusing but I hope I have explained myself well.
Let's see if something similar has happened to you and you know how to solve it.
Thanks in advance.
A greeting.
For personal inquiries, we answer you through our email.
Sincerely, the Mundoriego team.
You have a professional, in Cantabria, it worked fine for me and it stopped working. Thank you.
For personal inquiries, we contact you through our email.
Sincerely, the Mundoriego team.
Hello friends!!! I write to you from Argentina. I have a park of approximately 600 m2 with a sprinkler irrigation system controlled by a Hunter system. The installation from the water pump to the solenoid valves in each irrigation area has 40mm pipes and the hose that goes from the solenoid valves to the sprinklers is 3/4... I would like to add a venturi injector to have the possibility of fertilizing and even fumigate through sprinklers. Could you help me by indicating, for that size of pipes, what size injector should I buy? Thank you so much!
The choice of venturi injector depends on the flow rate you work with and the pressure available in your installation.
You should keep in mind that the pressure at the outlet of the venturi will be approximately half the inlet pressure.
We advise you to consult a manufacturer/distributor in your area so they can help you.
Sincerely, the Mundoriego team.