Sliver density sensing apparatus

An apparatus for sensing the density variation of a sliver, including a sliver funnel through which the sliver passes and which has an intake portion including an outlet opening having a diameter, a discharge portion adjoining the outlet opening of the intake portion and a chamber formed as an enlarged part of the discharge portion;

• the chamber having an inlet, an outlet and a lateral opening;
• the chamber being in communication with a source of pressurized air and a pressure sensing device through the lateral opening;
• the pressure sensing device receiving pneumatic signals as a function of the variation of pressure in the chamber dependent upon the density of the sliver portion momentarily present in the chamber;
• the improvement wherein said sliver funnel is arranged at an output of a carding machine for receiving a web discharged thereby and for combining it into a sliver passing through said chamber;
• said pressure sensing device comprising a pressure-responsive precision sensor including converter means for converting said pneumatic signals into digital signals;
• said converter means including means for emitting a first digital signal when the pneumatic signal exceeds a maximum predetermined value and means for emitting a second digital signal when the pneumatic signal falls below a minimum predetermined value;
• the value range between said maximum and minimum values representing a predetermined tolerance range of the density variation of the sliver.