Patent ID: 8763711

Claim:
A dry pipe sprinkler system comprising: at least one sprinkler head; a control valve operable to supply an extinguishant to the sprinkler head; a system of pipes interconnecting the control valve and the sprinkler head, the pipe system comprising a control column and a riser pipe; and a means for controlling pressure located downstream of the control valve and upstream of the sprinkler head; wherein the pipe system is arranged to form a manometer which contains a quantity of extinguishant up to a predetermined level in the control column and in the riser pipe; wherein the manometer is arranged such that the creation of a pressure differential across the means for controlling pressure results in a reduction in the extinguishant level in the control column and a rise in the extinguishant level in the riser pipe; and wherein the control valve is adapted to open to supply extinguishant to the sprinkler head when there is a change in the predetermined level of extinguishant in the control column and/or the riser pipe.