Medical fluid therapy machine including pneumatic pump box and accumulators therefore

A medical fluid delivery machine comprising:

• a medical fluid pump including a pneumatically actuated pump chamber and first and second pneumatically actuated medical fluid valve chambers located respectively upstream and downstream of the pneumatically actuated pump chamber;
• a pneumatic regulator for regulating positive pressure air;
• and
• an accumulator storing the positive pressure air for delivery to a destination having an operating pressure set by the pneumatic regulator, the destination including at least one of the pneumatically actuated pump chamber, the first pneumatically actuated medical fluid valve chamber, or the second pneumatically actuated medical fluid valve chamber, the accumulator holding an elastic bladder constructed with a wall thickness that is selected based on the set operating pressure and a pressure of the positive pressure air supplied to the accumulator for storage, wherein the elastic bladder inflates from a resting shape at a bladder inflation pressure, which is a positive pressure greater than the operating pressure set by the pneumatic regulator and less than the pressure of the positive pressure air supplied to the accumulator for storage, thereby creating additional positive pressure such that when the pressure in the bladder falls to the bladder inflation pressure from an initial pressure greater than the bladder inflation pressure, the bladder supplies the bladder inflation pressure until the bladder reaches its resting shape, wherein the accumulator includes an outer rigid housing holding the elastic bladder, wherein the bladder is held in a sealed relationship with the outer rigid housing, and wherein the outer rigid housing includes a vent port that is configured to enable air to escape the outer rigid housing as the bladder inflates.