Bellows pump device

A bellows pump device comprising:

• a pair of bellows expandable/contractible independently of each other and configured to suck a transport fluid thereinto by expansion thereof and to discharge the transport fluid therefrom by contraction thereof;
• a pair of driving units each having a suction-side fluid chamber and a discharge-side fluid chamber and configured to cause the respective bellows to expand to a predetermined expanded state by supplying a pressurized fluid to the suction-side fluid chambers and to cause the respective bellows to contract to a predetermined contracted state by supplying the pressurized fluid to the discharge-side fluid chambers;
• a pair of fluid pressure adjustment units configured to adjust fluid pressures of a pressurized fluid to be supplied to the suction-side fluid chambers of the respective driving units;
• a pair of detection units configured to detect expanded/contracted states of the respective bellows;
• and
• a control unit configured to control the pair of driving units and the pair of fluid pressure adjustment units on the basis of respective detection signals of the pair of detection units, wherein
• the control unit performs drive control of controlling the pair of driving units such that, before one bellows out of the pair of bellows comes into the contracted state, the other bellows is caused to contract from the expanded state,
• the control unit performs pressure decrease control of performing a pressure decrease determination of determining whether or not the other bellows has continued to be in the expanded state for a predetermined time or longer when the one bellows contracts to a mid-contraction state before the contracted state, and when a determination result of the pressure decrease determination is positive, outputting a pressure decrease command to the fluid pressure adjustment unit corresponding to the driving unit for causing the other bellows to expand, such that the fluid pressure at next expansion of the other bellows is decreased, and
• the control unit counts a number of times the pressure decrease control has been consecutively performed, and when the counted number of times has exceeded a predetermined number of times, the control unit determines that the fluid pressure adjustment unit is abnormal.