Bellows pump device

Abstract

A bellows pump device includes: a first electropneumatic regulator 51 that adjusts a first air pressure of pressurized air in a first discharge-side air chamber 21A of a first air cylinder unit 27; a second electropneumatic regulator 52 that adjusts a second air pressure of pressurized air in a second discharge-side air chamber 21B of a second air cylinder unit 28; and a control unit 6 that controls the first electropneumatic regulator 51 such that the first air pressure is continuously decreased during a period from a time when a second bellows 14 starts contracting until a first bellows 13 comes into a most contracted state, and controls the second electropneumatic regulator 52 such that the second air pressure is continuously decreased during a period from a time when the first bellows 13 starts contracting until the second bellows 14 comes into a most contracted state.

1 . A bellows pump device comprising:
 a pump head having a suction passage and a discharge passage for a transport fluid;   a first bellows and a second bellows mounted on the pump head so as to be expandable/contractible independently of each other and configured to suck the transport fluid from the suction passage thereinto by expansion thereof and discharge the transport fluid therefrom to the discharge passage by contraction thereof;   a check valve configured to permit flow of the transport fluid in one direction in the suction passage and the discharge passage and block flow of the transport fluid in another direction in the suction passage and the discharge passage;   a first driving unit having a first suction-side fluid chamber and a first discharge-side fluid chamber and configured to supply a pressurized fluid to the first suction-side fluid chamber thereby causing the first bellows to expand to a most expanded state, and supply the pressurized fluid to the first discharge-side fluid chamber thereby causing the first bellows to contract to a most contracted state; and   a second driving unit having a second suction-side fluid chamber and a second discharge-side fluid chamber and configured to supply a pressurized fluid to the second suction-side fluid chamber thereby causing the second bellows to expand to a most expanded state, and supply the pressurized fluid to the second discharge-side fluid chamber thereby causing the second bellows to contract to a most contracted state, wherein   the second bellows contracts from the most expanded state before the first bellows comes into the most contracted state, and the first bellows contracts from the most expanded state before the second bellows comes into the most contracted state, the bellows pump device further comprising   a first fluid pressure adjustment unit configured to adjust a first fluid pressure of the pressurized fluid in the first discharge-side fluid chamber of the first driving unit,   a second fluid pressure adjustment unit configured to adjust a second fluid pressure of the pressurized fluid in the second discharge-side fluid chamber of the second driving unit, and   a control unit configured to control the first fluid pressure adjustment unit such that the first fluid pressure is decreased stepwise or continuously during a period from a time at which the second bellows starts contracting to a time at which the first bellows comes into the most contracted state, and control the second fluid pressure adjustment unit such that the second fluid pressure is decreased stepwise or continuously during a period from a time at which the first bellows starts contracting to a time at which the second bellows comes into the most contracted state.   
     
     
         2 . The bellows pump device according to  claim 1 , wherein the control unit controls the first fluid pressure adjustment unit such that the first fluid pressure reaches zero before or when the first bellows comes into the most contracted state, and controls the second fluid pressure adjustment unit such that the second fluid pressure reaches zero before or when the second bellows comes into the most contracted state. 
     
     
         3 . The bellows pump device according to  claim 2 , wherein the control unit controls the first fluid pressure adjustment unit such that the first fluid pressure reaches zero at the time at which the first bellows comes into the most contracted state, and controls the second fluid pressure adjustment unit such that the second fluid pressure reaches zero at the time at which the second bellows comes into the most contracted state.