BZR-300 – Pressure Regulator Zero Governor 300°F/150°C

Industrial Combustion

The BZR-300 Pressure Regulators are designed to operate at elevated termperatures up to 300°F/150°C. They are designed for use as proportional gas/air control valves on burners and mixers.

Part Ref: ES111

Product Details

  • ¾" to 4" Valve sizes
  • Max. operating pressure: 140 mbar
  • Max. differential pressure: 36 mbar
  • Max. operating temperature: 150°C (300°F)
  • Turn-down range: 200:1
  • Sensitivity: 0.1 mbar
  • Accuracy: Low flow: ± 0.25 mbar, full flow: ± 0.76 mbar

They are double diaphragm Regulators. The first diaphragm, also called balancing diaphragm, is meant to divide the inlet gas chamber of the valve from the chamber under the main diaphragm; the second diaphragm balances out the outlet pressure of the lower chamber of the diaphragm itself and the pressure in the top chamber.

A compression spring loads the main diaphragm with an adjustable force which places the valve in an open position. When the outlet pressure under the main diaphragm equals the spring load, a balance of forces occurs to move the diaphragm and the valve assembly towards the closed position. The seal diaphragm is designed so that its area equals the effective area of the valve disc. Fluctuations in inlet pressure are thus counter-balanced by these two equal areas.

The upper diaphragm chamber is normally open to atmosphere while the lower diaphragm chamber, by means of the impulse connection, is subject to outlet pressure. With equal pressures in both chambers the valve stays closed; when there is an unbalance between the pressures of the lower and upper chambers (positive pressure in the upper chamber due to the charge or negative in the lower chamber due to the suction of a Venturi mixer) the valve moves downward letting more gas flow into the system. As changes in flow are required by the connected system, there will be slight changes in the outlet pressure and a minor unbalance in forces on the main diaphragm.



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