Patent ID: 11859600
Assignee: HITACHI HIGH-TECH CORPORATION
Field: Measurement (Instruments)
Classification: CPC F  G | IPC F  G

Claim 0:
1. A liquid feed pump which sucks or discharges a liquid, comprising:
a first plunger pump which sucks or discharges the liquid by sliding of a first plunger;
a second plunger pump which sucks or discharges the liquid by sliding of a second plunger; and
a liquid replacement mechanism which replaces the liquid to be introduced into the liquid feed pump, wherein
the first plunger pump and the second plunger pump are connected in series in a channel in which the liquid moves,
the first plunger is structured to be able to move between a first lower limit point and a first upper limit point in the first plunger pump,
the second plunger is structured to be able to move between a second lower limit point and a second upper limit point in the second plunger pump,
in the second plunger pump, a second plunger seal for sealing between a main body of the second plunger pump and the second plunger is located at a position nearer to the second lower limit point than to the second upper limit point,
when the liquid in the liquid feed pump is replaced, the first plunger slides back and forth in a space between the first lower limit point and the first upper limit point, and
when the liquid in the liquid feed pump is replaced, the second plunger stops at least temporarily at a position nearer to the second upper limit point than to the second lower limit point or slides back and forth for a shorter distance than when the liquid feed pump sucks and discharges the liquid.