together also function as a transfer coater in yet another embodiment papermaking machine 60 fig3 includes a semipermeable membrane 62 and a permeable membrane 64 for carrying a paper web 66 an air press 68 a cleaning fluid applicator 70 and conveyor rolls 72 air press 68 includes a box arrangement 74 mounted adjacent a suction roll 76 box arrangement 74 and suction roll 76 coact to form an entrance nip 78 and an exit nip 80 therebetween respectively through which semipermeable membrane 62 permeable membrane 64 and paper web 66 are fed into and out of air press 68 box arrangement 74 and suction roll 76 together define an air pressure chamber 82 box arrangement 74 has an air inlet line 84 associated therewith for introducing air under pressure into air pressure chamber 82 conversely suction roll 76 is provided with a vacuum line 86 for creating a negative pressure therein cleaning fluid applicator 70 is positioned prior to entrance nip 78 relative to a web travel direction 87 and adjacent semipermeable membrane 62 cleaning fluid applicator 70 includes a sprayer 88 and an applicator roll 90 sprayer 88 delivers cleaning fluid 92 onto applicator roll 90 which in turn transfers cleaning fluid 92 to semipermeable membrane 62 alternatively or additionally to cleaning fluid applicator 70 a cleaning fluid dispenser not shown could be provided within air pressure chamber 122 in a manner similar to cleaning fluid sprayer 42 b in fig2 a further embodiment of the invention is shown in fig4 specifically papermaking machine 100 includes a semipermeable membrane 102 and a permeable membrane 104 for carrying a paper web 106 an air press 108 a cleaning fluid sprayer 110 and conveyor rolls.