The present invention relates to a device for the production of foam (1) of a liquid, particularly of a food liquid such as milk, coffee or the like, comprising:
- a source of a liquid (13),
- a source of air (11) or another gas,
- a mixing device (3) in fluid communication with said liquid source (13) and with said air source (11) adapted to mix said liquid coming from said liquid source (13) with said air coming from said air source (11) to generate a foam of said liquid,
- a duct (7) in fluid communication with said mixing device (3) downstream of said mixing device (3), said foam flowing along said duct (7) in a flow direction (S) .
According to the invention, the device for the production of foam (1) comprises a foam sensor (100) associated with said duct (7). The foam sensor (100) comprises a radiation source (101) adapted to generate a radiation (103) which strikes said duct (7) along an irradiation direction (R) incident to said flow direction (S).
The foam sensor (100) further comprises:
- a first photodiode (105) placed on said irradiation direction (R) from a side opposite to said radiation source (101) with respect to said duct (7), said first photodiode (105) generating a first electrical signal (106) dependent on the radiation portion (107) which passes through said foam which flows along said duct (7), or
- a second photodiode (109) placed along a diffusion direction (D) substantially orthogonal to said irradiation direction (R), said second photodiode (109) generating a second electrical signal (110) dependent on the radiation portion (111) which is diffused by said foam along substantially said diffusion direction (D).