Liquid supply system

1. A liquid supply system, comprising:

a vessel configured to suck in a liquid from a first path communicating with an outside of the system and transmit the liquid that has been sucked in to a second path communicating with the outside of the system;

first and second bellows arranged in series in an expanding/contracting direction thereof in the vessel and having first end portions respectively, which are relatively close to each other and fixed to an inner wall of the vessel, and also having second end portions respectively, which are relatively distant from each other and movable in the expanding/contracting direction; and

a shaft which is inserted into the vessel and to which the respective second end portions of the first and second bellows are fixed, the shaft being reciprocally moved in the expanding/contracting direction by a drive source to expand/contract the first and second bellows, wherein

a first inner space of the vessel located outside the first bellows defines a first pump chamber provided with a first inlet port through which the liquid is sucked from the first path into the first pump chamber and a first outlet port through which the liquid that has been sucked in is transmitted from within the first pump chamber to the second path,

a second inner space of the vessel located outside the second bellows defines a second pump chamber provided with a second inlet port through which the liquid is sucked from the first path into the second pump chamber and a second outlet port through which the liquid that has been sucked in is transmitted from within the second pump chamber to the second path, and

a shared sealed space is formed inside each of the first and second bellows, wherein the internal pressures of the shared sealed space acting on the first and second bellows do not change even when the first and second bellows expand and contract.

2. The liquid supply system according to claim 1 , wherein the sealed space is in a vacuum state in which the pressure acting on the first and second bellows is only an external pressure.

3. The liquid supply system according to claim 1 , wherein the sealed space is filled with a gas.

4. The liquid supply system according to claim 1 , further comprising:

an internally evacuated outer vessel, wherein

the vessel is placed in the outer vessel so as to be surrounded by a vacuum space, and

the shaft is inserted into the vessel so as to extend from outside the outer vessel and reach the inside of the vessel.

5. The liquid supply system according to claim 1 , further comprising:

a third bellows disposed in series to the second bellows in the expanding/contracting direction and having one end portion fixed to the vessel such that an inside of the third bellows is open to the outside of the vessel and also having the other end portion coupled to the second end portion of the second bellows, wherein

the third bellows expands/contracts in conjunction with the expansion/contraction of the second bellows, and

the shaft is inserted through the inside of the third bellows and coupled to the respective second end portions of the first and second bellows.

6. The liquid supply system according to claim 5 , wherein the third bellows has an outer diameter smaller than an inner diameter of the second bellows and is disposed so that at least a part thereof is located inside the second bellows.

7. The liquid supply system according to claim 2 , further comprising:

an internally evacuated outer vessel, wherein

the vessel is placed in the outer vessel so as to be surrounded by a vacuum space, and

the shaft is inserted into the vessel so as to extend from outside the outer vessel and reach the inside of the vessel.

8. The liquid supply system according to claim 3 , further comprising:

an internally evacuated outer vessel, wherein

the vessel is placed in the outer vessel so as to be surrounded by a vacuum space, and

the shaft is inserted into the vessel so as to extend from outside the outer vessel and reach the inside of the vessel.

9. The liquid supply system according to claim 2 , further comprising:

a third bellows disposed in series to the second bellows in the expanding/contracting direction and having one end portion fixed to the vessel such that an inside of the third bellows is open to the outside of the vessel and also having the other end portion coupled to the second end portion of the second bellows, wherein

the third bellows expands/contracts in conjunction with the expansion/contraction of the second bellows, and

the shaft is inserted through the inside of the third bellows and coupled to the respective second end portions of the first and second bellows.

10. The liquid supply system according to claim 3 , further comprising:

a third bellows disposed in series to the second bellows in the expanding/contracting direction and having one end portion fixed to the vessel such that an inside of the third bellows is open to the outside of the vessel and also having the other end portion coupled to the second end portion of the second bellows, wherein

the third bellows expands/contracts in conjunction with the expansion/contraction of the second bellows, and

the shaft is inserted through the inside of the third bellows and coupled to the respective second end portions of the first and second bellows.

11. The liquid supply system according to claim 4 , further comprising:

a third bellows disposed in series to the second bellows in the expanding/contracting direction and having one end portion fixed to the vessel such that an inside of the third bellows is open to the outside of the vessel and also having the other end portion coupled to the second end portion of the second bellows, wherein

the third bellows expands/contracts in conjunction with the expansion/contraction of the second bellows, and

the shaft is inserted through the inside of the third bellows and coupled to the respective second end portions of the first and second bellows.