I have 3 I2C flow sensors, but I can't change their address. What can I do to realize the communication? There is some multiplexer shield of 3 inputs?

 

I have 3 I2C flow sensors, but I can't change their address. What can I do to realize the communication? There is some multiplexer shield of 3 inputs?

Yes, you can look for an I2c port extender chip. Send a select signal to the port extender and it will route your bus to the right sensor.

 

For example, a I2C expander similar to:
MCP23008 - i2c 8 input/output port expander : ID 593 : $1.95 : Adafruit Industries, Unique & fun DIY electronics and kits

 

No mention of the microcontroller used. I2C can easily be implemented in software if not already...You just need two pins for each separate I2C bus.

 

The MCP23008 is GPIO extender, you need a i2c multplexer