The opposite side of the carriage is fixedly fitted with a compressible silicone rubber or other resilient valve member in sealing engagement with {HEAD ~ a port plate} to carry out {TAIL ~ vacuum valving functions} 
The opposite side of the carriage is fixedly fitted with a compressible silicone rubber or other resilient valve member in sealing engagement with { HEAD ~ a port plate } to carry out { TAIL ~ vacuum valving functions }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL