Tube 1 is made of a material with a larger coefficient of linear expansion than that of rod 2 inside the tube. The outer end of rod 2 is rigidly attached to tube 1 and the inner end slides in guide bushing 3. This end of rod 2 contacts the tip of screw 4 which is screwed into lever 5. Lever 5 has two supports 6 on which it turns. On its other end, lever 5 has shutter 8, opposite which is cylindrical nozzle 9. Fluid delivered to nozzle 9 flows in through the clearance between the shutter and nozzle and out through port 7. The thermoelement is immersed into the medium whose temperature is to be controlled. When the temperature increases, tube 1 expands more than rod 2 which is pulled into the tube. At this, lever 5 turns counterclockwise and shutter 8 approaches nozzle 9, reducing the clearance through which the fluid flows. This raises the pressure in the cylinder of a servomotor (not shown) which makes the necessary changes in the item being controlled. When the temperature drops, the elements of the regulator operate in the reverse direction.
$3902$LHP,Rg$