| 摘要 |
<p>The invention relates to a vacuum pumping circuit comprising: an upper chamber (34) and a lower chamber (36) that communicate via a connecting orifice (38), and comprising a valve (40) provided with a stem guided so as to slide along a vertical axis (A1) in order to close the connecting orifice (38), which circuit is characterized in that the valve stem (48) is provided with a section forming a piston (52) which constitutes the mobile upper wall of a control chamber (54) communicating with the upper chamber (34), the piston (52) having an upper face (56) at atmospheric air pressure and a lower face (58) on which the pressure is that present in the control chamber (54).</p> |
