Our company is installing flow meters on an old polyurethane foam machine. After some research, ultrasonic flow meters were chosen as they have no moving parts and are easy to clean. Polyurethane foam is produced by mixing polyol with isocyante (not as bad as it sounds) at a fairly precise ratio. However, the ultrasonic flow meter will not work with the polyol. The polyol we are using is the polyether type.
According to the manufacturer any polyol should not be a problem, nor should the viscosity be a problem. Apparently they have used the same flow meters for honey and glycerin and they work well in those applications.
Why would the flow of polyether polyols not be able to be measured in an ultrasonic flow meter?