Pressurized diaphragm pump and directional flow controller therefor

A valve for fluid comprising:

• a chamber having at least first and second fluid conduits;
• means, located within said chamber and operating in conjunction with said first fluid conduit, for regulating a first pressure within said chamber at a different level than a second pressure without said chamber;
• a first plate mounted within said chamber, said plate including said second fluid conduit;
• a second plate having a surface, said surface having a slot, said surface sealingly engaged with said first plate, said slot immersed in fluid within said chamber at the first pressure;
• and
• means for moving said second plate against said first plate alternately to permit and prevent passage of fluid at the first pressure through said slot and between said second fluid conduit and said chamber;
• wherein said first plate includes a vent extending without said chamber;
• and wherein said surface of said second plate includes a hollow located in fluid communication with said vent, and said second plate surface seals said vent and hollow from said chamber;
• and wherein, as said second plate moves, said hollow periodically brings said vent and said second fluid conduit into fluid communication.