the inner chamber 70 defined above and is retained therein by the cap nut 5 and the bushing 101 as with the ism 100 unlike the ism 100 shown in fig3 with a single piece plunger 103 the plunger of the ism 300 is segmented for ease of manufacturing and built out of two or more parts coupled together as desired as above the keys or pins and corresponding grooves and bores possibly used for the coupling of jointly rotating parts and for relative translation displacement are not mentioned for the sake of simplicity only functional features of the machine parts are depicted and described with reference to fig7 the segmented plunger 301 is a made for example of two separate sections coupled together namely a plunger base 301 and a separate opening cone 303 resembling the rod head 211 of the ism 100 in fig8 the plunger base 301 is shown with a front plunger pipe 305 and a plunger main body 307 both connected on the inside by an axial bore 309 of constant or variable inner diameter accommodated for the passage of fluid the axial bore 309 extends from a flange inlet 311 opened in a hollow flange 313 at.