Single piston foundation bag-in-box (BIB) pump

A pump (10) comprising:

• a gas housing (20) having a first gas chamber (21a), a second gas chamber (21b), a gas exhaust fitting (60) configured to provide inlet gas to the first gas chamber (21a), and a gas inlet fitting (62) configured to provide outlet gas from the second gas chamber (21b);
• a liquid housing (30) having a liquid chamber (31a), a liquid outlet fitting (64) configured to provide liquid from the liquid chamber (31a), and a liquid suction fitting (66) configured to provide the liquid to the liquid chamber (31a), having a single piston/diaphragm assembly (32) with a spring (36) and being arranged between the second gas chamber (21b) and the liquid chamber (31a), the single piston/diaphragm assembly (32) drawing the liquid from the liquid inlet fitting (66) into the liquid chamber (31a) during a suction stroke and providing the liquid from the liquid chamber (31a) to the outlet fitting (64) during a pressure stroke;
• the spring (36) being configured in the liquid chamber (31a) to store energy during the pressure stroke and provides the suction stroke;
• and
• a slide valve assembly (22) being arranged in the first gas chamber 21a and being movable between a pressure stroke state and a suction stroke state for alternately providing pressurized gas to the second gas chamber (21b) so that the liquid passes from the liquid chamber (31a) to the liquid outlet fitting (64), and providing gas from the second gas chamber (21b) to atmosphere, so that the spring (36) provides the suction stroke and liquid is drawn from the liquid inlet fitting (66) into the liquid chamber (31a), characterized in that
• the slide valve assembly (22) comprises a block or housing assembly (22a) and an actuator assembly (22b);
• the block or housing assembly (22a) comprises a slide valve housing (22a1) configured with a cavity;
• the actuator assembly (22b) comprises a slide block (22b1) configured to slide in the cavity of the slide valve housing (22a1);
• the actuator assembly (22b) having a slide spring (22b3) arranged between a lower retainer (22b2) and an upper retainer (22b4) forming an actuator combination under compression, and a yoke (22b5) configured with an opening to contain the actuator combination under compression;
• a piston shaft/actuator slide assembly (26) coupling the yoke (22b5) and the single piston/diaphragm assembly (32) causing the slide valve assembly (22) to change between the pressure stroke state and the suction stroke state;
• and
• the single piston/diaphragm assembly (32) comprises a piston (32a) and a diaphragm (32b), the piston (32a) being coupled to the slide valve assembly (22) via a piston shaft/actuator slide assembly (26), and the diaphragm (32b) being coupled between the gas housing (20) and the liquid housing (30).