Back Pressure Relating To Venturi Injector Method

Posted by Brialle Veldman on June 6, 2017 under Ozone for Beginners | Be the First to Comment

When it comes to introducing ozone gas into water, there is more than one method. Venturi injector is probably the most common when it comes to handling higher concentrations of ozone. Venturi injectors work by forcing water through a conical body, which initiates a pressure differential between the inlet and outlet ports. This creates a vacuum inside the injector body, which initiates ozone suction through the suction port. This leads us to have to understand back pressure. For example, a pump delivering 18 GPM at 15 PSI can inject a maximum of 20 SCFH (10 LPM) of air if 7 PSI of back pressure exists.

If more suction is needed two options exist:

  1. Increase the size of the pump
  2. Decrease the injector outlet pressure by increasing the diameter of the pipe, reducing the number of elbows or lowering the height of the delivered water.

The greater the pressure differential, the more suction you will have.

 

Venturi Injector picture

(Venturis require a constant pressure differential to initiate ozone injection (15 PSI in this example).

When it comes to comparing two different types of generators, there are differences to keep in mind when you’re using a venturi injector method.  First, depending on the pump, your flow will be different. Our TG-Series is able to withstand higher pressures and is a popular choice because of that exact reason, which means it creates higher concentrations of ozone. If you maintain 10-25 PSI back pressure, you will achieve the ideal ozone concentration ranges. If it is above 35 PSI, you will not achieve as high of concentrations. Our OZV-Series is not able to withstand high pressures, (lower than 5 PSI) but is still a popular choice for applications with concerns to having lower concentrations for a cost-effective solution. Therefore, when utilized with a contact tank, back pressure is required to remove off-gas. When the water pressure is above 50 PSI, the concentration of ozone dissolved into the water decreases due to ozone off-gas. We highly recommend having a minimum of 5 PSI and a maximum of 50 PSI on your contact tank. The importance of this pressure range is to remove large undissolved ozone gas and not forcing the dissolved ozone to leave the solution.

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