Sonotrode (10) and device (20) with at least one sonotrode (10) for generating an ultrasonic field in industrial production processes such as chemical, food, petroleum, pharmaceutical, beverage or mining-related processes for reducing and eliminating foaming of liquid products with a compact one-piece form of the sonotrode body, wherein the sonotrode (10) is provided with a main body part (1) having connecting means for connection with a high frequency generator and having a front face (2) from which the ultrasonic field is directed to the desired spot or area of the product (3) to be de-foamed, wherein the main body part (1) has the shape of a compact block element and in that the front face (2) is concave in shape in relation to a product surface such that the ultrasonic field is focused and directed to a specific area of a product foam (3) to be treated in a concentrated form compared to a non-focused ultrasound.
