body 162 an actuating body 164 and a central stud 166 respectively replace the chamber 14 main body 16 the actuating body 18 and the central stud 24 of the first embodiment shown in fig1 and 2 in fig6 an alternative connecting means to that of the first embodiment shown in fig1 and 2 for connecting the main body 162 to the chamber 160 is shown which uses a plurality of screws 168 to attach the main body 162 to the chamber 160 the main body 162 comprises a lower part 170 with a smooth surface which fits in the chamber opening 172 which also have a smooth surface there is a flange 174 on the main body 162 with a plurality of openings 176 where the screws 168 can pass on the top edge surface of the chamber 160 there are plurality of threaded holes 178 matching the treads of screws 168 the screws 168 can pass through the openings 176 of the flange 174 and be screwed in the threaded holes 178 in the chamber 160 connecting the main body 162 into chamber 160 pushing the lower surface of the main body 162 against the step 40 and the sealing member 36 sealing the connection still referring to fig6 in case of using a material such as teflon which may.