Gas injection device

Abstract

To provide a gas injection device capable of suppressing the entry of liquid from an injection part into the device.SOLUTION: The gas injection device includes a cylinder having the injection part at one axial end, a piston capable of reciprocating along the axial direction, an energizing member for energizing the piston to come close to the injection part, a drive part for moving the piston to go away from the injection part, and a sealing member arranged in a region where the piston is opposed to the injection part while expanding in the radial direction, th cylinder having an opening part expanding in the radial direction until leading to the injection part, in one axial end at its inner end wall expanding in the radial direction, the sealing member having an annular protrusion part arranged on the radial outer periphery part while extending to the inner end wall for contacting the inner end wall outside of the radial outer peripheral edge of the opening part when neighboring the inner end wall, and serving for closing the opening part.SELECTED DRAWING: Figure 6

Claims

[Claim 1] A cylinder having an injection nozzle at one end in the axial direction, A piston disposed within the cylinder and capable of reciprocating along the axial direction, A biasing member that biases the piston in a direction that brings it closer to the injection part, A drive unit that moves the piston in a direction away from the injection unit, A sealing member made of an elastic material, positioned on the end face of the piston on one axial end side, in the region of the piston facing the injection portion in the axial direction, and extending radially in a direction intersecting the axial direction, Equipped with, The cylinder has an inner end wall that extends radially at one end in the axial direction, and an opening that extends radially and continues to the injection section. The sealing member is arranged on the radial outer circumference and extends toward the inner end wall, and has an annular projection that contacts the inner end wall outside the radial outer edge of the opening when adjacent to the inner end wall, and the projection is sandwiched between the inner end wall of the cylinder and the end face of the piston by the biasing member to close the opening, the gas injection device. [Claim 2] The gas injection device according to claim 1, wherein the projection has an annular planar portion facing the inner end wall in the axial direction. [Claim 3] The gas injection device according to claim 1, wherein the projection has an annular curved portion that faces the inner end wall in the axial direction and protrudes toward the inner end wall. [Claim 4] The gas injection device according to claim 1, wherein the projection has an annular triangular prism portion that faces the inner end wall in the axial direction and protrudes toward the inner end wall. [Claim 5] The gas injection device according to claim 1, wherein the piston is positioned inside the radial outer edge of the sealing member and has a gas flow path that penetrates axially and through which gas can flow. [Claim 6] The drive unit is equipped with a control unit that controls the operation of the drive unit, The gas injection device according to any one of claims 1 to 5, wherein the control unit brings the piston adjacent to the inner end wall when the operation of the drive unit stops.

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