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 16 is connected by turning pairs C and D to hand 2 and to lever 3 which, in turn, is connected by turning pair B to the rod of bellows 13 and carries shutter a. When the pressure rises in the item being regulated, hand 2 turns counterclockwise, and shutter a is retracted from nozzle 4 to which compressed air is delivered through tube 5 and flow-control valve 6. Compressed air is also delivered throuigh flow-control valve 9 to the chamber of valve 8 whose ball is linked to bellows 7. The chamber of bellows 7 is connected to nozzle 4. The chamber of valve 8 is connected to the atmosphere and to the membrane chamber of servomotor 10. As shutter a 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, pressure on the membrane of servomotor 10 increases and valve 11 is closed to some extent, reducing the supply of heat-carrying agent to the system. The increase in air pressure is transmitted to feedback bellows 12 with a certain lag owing to the provision of flow-control valve 15 whose clear opening can be regulated. During this lag, the pressure on the membrane of servomotor 10 continues to remain more than it would be with ordinary operation of a feedback bellows, i.e. one without flow-control valve 15. With this arrangement, regulating valve 11 first greatly reduces the supply of heat-carrying agent, thereby tending to decrease a subsequent deviation of the parameter being regulated and reduce the length of the transient state. Upon deformation of bellows 12 and 13, the pressure of air in them increases. As a result, a part of the air is released through flow-control valve 14 to the atmosphere, and shutter a smoothly returns to its initial position. When the pressure in the system drops, the elements of the regulator operate in the reverse direction.
$4094$EHP,Rg$