After a survey of the existing Coriolis mass flowmeters, all based upon the elastic deformation of the resonant sensor, this paper describes a new type of Coriolis mass flowmeter realised, in a prototypal way, in the DIME laboratories. The flowmeter prototype is composed of two attached elements: a stiff tube and an original system of independent elastic suspension which lets the whole sensor vibrate. In such a way, the new type of elastic suspension permits measurement independent from the elastic properties of the tube, not subject to deformation, realising a new mass flow sensor. The DIME prototype, which is described in the present paper, was studied and realised with the main aim of checking the mechanical behaviour of the new type of uncoupled elastic suspension. Being the prototype and not a production-engineered version, for which it is possible to provide the metrological performances, the DIME flowmeter was tested on the DIME calibration facility, and the experimental results, which prove the linear behaviour of the prototype, are reviewed.