Venting appts. for mixing and conveying device

摘要

The venting appts. has a compressor connected to a mixing vessel (10), which is switched off, after the transfer of mixed material from it is complete. The venting device is held shut by internal pressure, as long as the latter remains above a pre-set threshold. The appts. comprises a non-return valve (NRV) (30), closed by a lever (36), and spring biased to open when the pressure drops below the threshold. When this occurs, the NRV or its link (36) operates the switch (48), switching off the compressor. Conversely, when the NRV is re-closed, the compressor is switched on.