Regulators - Siemens
Nullmatic 40, 41, 42 precision regulators
The series 40, 41, 42 Nullmatic® Pressure Regulator range uses the null-balance principle, which holds the output pressure constant regardless of wide changes in flow or supply pressure. Each regulator is in essence a self-contained pressure controller.
A fine-turn, precision screw is used to manually load the range spring which sets the regulated pressure.
When the adjusting knob is turned clockwise, the increased spring force is exerted on the top diaphragm assembly which decreases the nozzle clearance and increases the pilot pressure. The source for pilot pressure is supply air flowing to the pilot pressure chamber through the restriction screw. The increased pilot pressure forces the exhaust diaphragm assembly downward, closing the exhaust port, contacting and moving the valve plunger and thereby opening the supply port. This increases the regulated output which also feeds back to the top diaphragm assembly. The regulator locks-up or throttles at the new output value when the feedback force of the top diaphragm assembly equals the range spring force.
A safety release valve is incorporated in the top diaphragm assembly of the -2 through -50 models. The safety release operates if the regulated pressure becomes 3 to 5 psig more than the set pressure. It exhausts air through the atmospheric vent in the top housing. An over-pressure causes the diaphragm to move upward, opening the safety release valve when the valve motion is stopped by the stripper plate
The series 40, 41, 42 Nullmatic® Pressure Regulator range uses the null-balance principle, which holds the output pressure constant regardless of wide changes in flow or supply pressure. Each regulator is in essence a self-contained pressure controller.
A fine-turn, precision screw is used to manually load the range spring which sets the regulated pressure.
When the adjusting knob is turned clockwise, the increased spring force is exerted on the top diaphragm assembly which decreases the nozzle clearance and increases the pilot pressure. The source for pilot pressure is supply air flowing to the pilot pressure chamber through the restriction screw. The increased pilot pressure forces the exhaust diaphragm assembly downward, closing the exhaust port, contacting and moving the valve plunger and thereby opening the supply port. This increases the regulated output which also feeds back to the top diaphragm assembly. The regulator locks-up or throttles at the new output value when the feedback force of the top diaphragm assembly equals the range spring force.
A safety release valve is incorporated in the top diaphragm assembly of the -2 through -50 models. The safety release operates if the regulated pressure becomes 3 to 5 psig more than the set pressure. It exhausts air through the atmospheric vent in the top housing. An over-pressure causes the diaphragm to move upward, opening the safety release valve when the valve motion is stopped by the stripper plate
