Hand 2, turning about fixed axis A, is linked to Bourdon tube 1 which is connected to the item whose pressure is to be regulated. Link 12 is connected by turning pairs B and C to hand 2 and to shutter 3, which turns about fixed axis D and approaches nozzle 4. Compressed air is delivered through tube 5 and flow-control valve 6 to nozzle 4. The nozzle is also connected to bellows 7 to which the ball of valve 8 is linked. The air delivered to valve 8 through flow-control valve 9 is at the same pressure as that delivered to nozzle 4. The chamber of valve 8 is connected to the atmosphere and to the membrane chamber of servomotor 10. When the pressure rises above normal, hand 2 turns counterclockwise, shutter 3 is retracted from nozzle 4, the pressure in bellows 7 drops, and the ball of valve 8 is raised, closing off air discharge to the atmosphere. After this, the pressure on the membrane of the servomotor increases and valve 11 is closed to some extent, reducing the supply of the heat-carrying agent to the system. When the pressure in the system drops, hand 2 turns clockwise, shutter 3 approaches nozzle 4, restricting the flow. This raises the pressure in bellows 7, lowering the ball of valve 8 and reducing the flow of air to the servomotor whose membrane chamber is connected to the atmosphere. Valve 11 is opened by the weight and it increases the supply of heat-carrying agent to the system.
$4087$EHP,Rg$