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Magnetic Level Indicator
Pneumatic Temperature Controllers (Model: PTC-19)
Pneumatic Temperature Controllers
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PNEUMATIC TEMPERATURE CONTROLLERS Operation and Working Principle
 
The sensor element consists of a Bimetal combination having different thermal expansion coefficient. This difference in their thermal expansion coefficient produces a mechanical motion. The sensing element of the Controller is installed directly in the process vessel. The temperature changes inside the process will result in the following
  • Incase of a rise in temperature, the inner metal rod will expand and will contract incase of a decrease in temperature. The change in length is proportional to the change in temperature.
  • The outer metal tube has a low expansion coefficient and thus change in length is negligible. But since one end is attached to the inner metal tube, the inner rod moves as the outer tube changes length.
  • The opposite end of inner rod pushes against a floating link. It is held concentric with a spring loaded inner valve. When the temperature decreases, the inner rod applies pressure on the floating link, it causes pivot to move around the adjustment fulcrum point which tilts the inner valve plug thus the output signal increases. The temperature can be adjusted by moving the knob on the fulcrum.
 
PNEUMATIC TEMPERATURE CONTROLLERS Introduction
 
The instrument is provided with two adjustments (a) temperature set Point control and (b) Proportionality control. The temperature can be adjusted and where between - 50° F to + 750° F. The proportionality control is given to set the desirable temperature span. The proportionality control, calibrated from 5 to 60° F corresponds to produce 0.2 - 1 Kg / cm2 output.

The orifice in the seat is eccentrically drilled so that while rotating the seat it moves the rifice with respect to the adjusting serew. This regulates the orifice opening with respect to temperature changes.
 
PNEUMATIC TEMPERATURE CONTROLLERS Specifications
Connection ¾" NPT (M)
Thermowell MOC SS 316
Length 300 mm
Service Oil / Water
Operating Pressure 20 Bar or Kg / cm2
Temperature Range -50 to 750 Deg F
Supply Pressure 1.4 Kg / cm2
Output 0.2 to 1 Kg / cm2
Pneumatic Connection ¼" NPT
Action Reverse (Increase in temperature will decrease output)
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