The apparatus 3 wherein {TAIL ~ said inner sidewall} extends from a region above said conveyor past an outer edge of said conveyor to a region below {HEAD ~ said conveyor}, and said second airlock means comprises a bottom wall extending beneath said conveyor and connecting with said outer wall 
The apparatus 3 wherein { TAIL ~ said inner sidewall } extends from a region above said conveyor past an outer edge of said conveyor to a region below { HEAD ~ said conveyor } , and said second airlock means comprises a bottom wall extending beneath said conveyor and connecting with said outer wall
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH