Linear displacement sampling valve and a device for fixing same

In a linear displacement sampling valve and a device for fixing the elements thereof formed essentially by a central mobile element with at least one transverse passage orifice and adapted for effecting a sliding movement under the action of a drive means of the cylinder and piston kind, so that the transverse orifice is aligned with one or the other of several opposite orifices provided on fixed guide parts placed on each side of said central element, said central sliding element and its two fixed lateral guide parts are profiled and chamfered so as to have bearing faces with a reduced friction area and form a substantially parallelepipedic assembly which is held in position on four of its faces by fixed members forming a cradle therefor, and which is held in position on a fifth face thereof by a manual release locking flange and on its sixth face by a clamping member of the quick release pivoting type.