Patent ID: 7963211

Claim:
A reciprocating compression installation ( 1 ) for compressing a useful gas, comprising: at least one cylinder determining a compression chamber provided with at least one intake and at least one outlet for the compressed useful gas; a piston collaborating with the cylinder, with an operating rod emerging therefrom; a cylinder end a passage through which the piston rod can pass in a linear and reciprocating manner; a sealing device, of the stuffing-box type, sealing between the piston rod and the cylinder end, with respect to the useful gas, comprising a stack along the axis of the rod, of the stuffing-box type, of, on the one hand, a multitude of annular packings and, on the other hand, at least one insert ring designed to form a radial passage from an internal annular gap adjacent to the piston rod to at least one external peripheral cavity adjacent to the internal face of the passage in the cylinder end or in the body of the sealing device; and at least one port formed in the cylinder end or in the body of the sealing device and communicating in a sealed manner with the cavity of the sealing device; wherein, in collaboration: a) there is a source of insulating gas, which is separate from the useful gas but is under pressure; b) the stack of the sealing device comprises two insert rings, one of them, the anterior ring, some distance from the cylinder, and the other, the posterior ring, closest to said cylinder; and c) the cylinder end or the body of the sealing device has two ports, an anterior port and a posterior port, which are formed in communication, on one side, with the two external peripheral cavities of the two insert rings, namely the anterior and posterior rings respectively, and, on the other side, at least in the case of the anterior port, with the source of insulating gas so as to generate, from an internal annular gap, a tubular insulating gas path for the insulating gas, along the piston rod, practically from one end of the sealing device to the other.