Fine adjustable firing valve

A finely adjustable firing valve for rapidly discharging compressed air or compressed gas, for the purpose of generating a pressure wave in silos or containers of granular materials, comprising

• a pneumatic main valve (1) presenting a valve body (2) with an inlet (3) and a discharge (5) connected together via a main actuation chamber (8),
• a main access (26) connecting the inlet (3) to the main actuation chamber (8), and
• a main port (6) connecting the main actuation chamber (8) to the discharge (5),
• said main valve (1) also comprising
• a main valving element (7) arranged to move within said main actuation chamber (8) to alternately connect the inlet (3) to the discharge (5) or the inlet (3) to a first connection conduit (11) which opens into the main actuation chamber (8),
• said firing valve further comprising a pneumatic secondary valve (9), arranged to control the main valve (1) by acting on said main valving element (7), and comprising
• a secondary actuation chamber (15) of volume less than the main actuation chamber (8), and connected by said first connection conduit (11) to the main actuation chamber (8),
• a secondary discharge (12) connected to the secondary actuation chamber (15), a secondary access (10) connecting the first connection conduit (11) to the secondary actuation chamber (15), and
• a secondary port (13) connecting the secondary actuation chamber (15) to the secondary discharge (12),
• said secondary valve (9) also comprising a secondary valving element (14) arranged to move within said secondary actuation chamber (15) to alternately connect the first connection conduit (11) to the secondary discharge (12) or the first connection conduit (11) to a second connection conduit (18) which opens into the secondary actuation chamber (15),
• said firing valve further comprising a pilot valve (16), arranged to control the secondary valve (9) by acting on said secondary valving element (14) via said connection conduit (18),
• characterised in that
• said main valving element (7) is of membrane type, it is fixed to the centre of the main actuation chamber (8), and it can move within the main actuation chamber (8) by rising and falling peripherally.