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Pressure Reducing Regulator Model 80 / 829s and 81 / 829s

NOMINAL SIZE RANGE (mm) : 25, 100 TO 300 (80/829s) or 40 TO 80 (81/829s)
PN100 (80/829s) or PN50 (81/829s)
ANSI CLASS 600 (80/829s) or ANSI CLASS 300 (81/829s)

Application :

The model 80/81 regulator / pilot combination reduces pressure in gas or liquid systems. The pilot, a small spring loaded diaphragm regulator, establishes the reduced pressure setting.
Ainsworth model 80 ( or model 81 ) Regulator :
The Ainsworth model 829s pilot works with both types of regulators. The regulator consists of a body, closures, an elastic tube, and a core.
The valve position (open, partially open or closed) is determined by the position of the tube. If the tube is seated tightly around the core, the valve is “closed”. If the tube is pushed out, against the body, the valve is “wide open”. When the tube is between the “closed” and “wide open” positions, the valve is “partially open” or “throttling”. The “Jacket” is the (annular) space between the tube and the body. The relationship of the “Jacket” to “Inlet” pressure determines the position of the tube. If the Jacket is vented to atmosphere or to downstream with sufficient differential pressure, the inlet pressure will stretch the tube against the body. If the jacket pressure is equal to the inlet pressure, the initial tension (from stretching the tube over the core) will keep the tube seated against the core.
The regulator body and closures have ports (bosses) to access the inlet (I-boss), downstream (D-boss), and jacket (J-boss) pressures.

Ainsworth model 829s Pilot :

The pilot is an adjustable spring loaded, diaphragm actuated regulator with an integral inlet variable orifice. Increasing the spring force, raises the pressure setting of the pilot. To increase the pressure setting turn the adjusting screw on the top of the spring barrel clockwise. The pilot has six springs available, each for a different control pressure range.

Principle of Operation

The regulator – pilot combination maintain a constant downstream line pressure by controlling the amount of fluid or gas passed through the regulator. When outlet line pressure is above the set pressure of the pilot, the pilot remains closed. The closed pilot seals the regulator jacket from the downstream line, so the jacket pressure (Pj) equalizes with the inlet pressure (Pi), closing the regulator.
When outlet line pressure falls below the set pressure of the pilot, the pilot opens and allows the fluid in the jacket to flow out to the downstream line. At the same time, the fluid flowing from the inlet into the jacket is choked by the restricting orifice, so the flow into the jacket is less than the flow out, and the jacket pressure drops, opening the regulator.
While the line is flowing the pilot remains open, but as the downstream pressure starts to rise, the pilot starts throttling, and the flow out of the regulator jacket is balanced by the flow in.
During this action, the jacket pressure is still lower than inlet line pressure, and the regulator valve will also be throttling.
When downstream pressure rises to equal the set pressure of the pilot, the pilot stays at an equilibrium throttling position so that flow into jacket through the restricting orifice equals flow exiting through the pilot. The regulator pilot combination stay in their equilibrium position until the flow conditions change.

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Contact Details:

Tel: (011) 433-3968
Fax: (011) 433-9107

Physical Address:

44 Harry Street
Johannesburg South