P C McKenzie Company

Industrial Boiler and Natural Gas Compressor Sales

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Axelson Actuator Pneumatic Diaphragm Actuator

Axelson - Pneumatic Diaphragm ActuatorAxelson Actuator  – Pneumatic Diaphragm Actuator

The AUD pneumatic actuator is designed for simplicity, ease of maintenance and adaptability.  Its modular design and few components help improve field performance.

This actuator is designed to close upon loss of control pressure (fail-safe). The actuator’s nylon-reinforced diaphragm has a large piston area allowing for a low control pressure.

The maximum control pressure is 150 psi. Due to it’s fail safe design, the actuator is ideally suited for wellhead, flowline, header, pipeline system, and casing relief blowdown valve applications.

Actuators are available for API gate valve sizes from 1-13/16 in. through 12 in. and larger upon request.

actuator-size

Benefits

  • Less maintenance – Rolling diaphragm design eliminates moving o-ring seals and leads to longer seal life.
  • Proven reliability – API 6A, PR2 Appendix F qualified packing
  • Lightweight – Easy to install and maintain. Can be redressed without special tools or external pressure sources.
  • Quick disconnect – Actuator can be removed from the valve without the use of special tools or an external pressure source.
  • Large diaphragm area – Permits use of a low pressure air or gas control system. A relief valve on the cylinder acts to protect against damage to the diaphragm in case of excessive pressure increases.
  • Visual open – close indication – Upper stem extension indicates gate position at a glance.

actuator-design3Actuator Design and Principle of Operation

Pneumatic control pressure enters the cylinder. The extended stem travels downward indicating the valve is open. The adjustable downstop prevents further downward movement. The gate valve is now fully open. The actuator is designed to maintain the valve (reverse-acting) in the open position with pneumatic pressure on top of the diaphragm.

Loss of pneumatic pressure allows pressure in the valve body and spring force to move the stem and gate into the closed position. The extended stem indicates the valve is closed. The metal-to-metal seat between the actuator bonnet and lower stem serves as a secondary seal. Upstream valve body pressure helps to hold the gate in the closed position. The spring allows the gate to close with less than 100 psi in the valve body.

 

Pneumatic Diaphragm ActuatorA surface safety valve is a full-opening, pressure-actuated, normally closed gate valve.

When control pressure is released, the valve is designed to close even when subjected to high flow line pressure.

It closes completely and rapidly as the control pressure is released.  Flowline fluid does not enter the operator mechanism, nor exhaust to the atmosphere when the valve operates.

The surface safety valve assembly consists of a hydraulic or pneumatic actuator which operates a reverse-acting gate valve.  The actuator design makes it an integral part of the valve assembly by adapting directly to the valve bonnet.

Pressure applied above the piston pushes the piston, stem, and gate down.  This downward movement opens the gate in reverse-acting gate valves.

Pressure in the valve body is sealed at the lower stem and prevented from entering the actuator assembly.  The area below the piston is vented to the atmosphere.

When control pressure above the piston is exhausted by the operation of the pilot system, the valve closes.  Valve body pressure works across the area of the lower stem to force it out of the valve body, drawing the gate into the closed position.

With no pressure (less than 100 psi) in the valve body, the spring returns the valve to the closed position.

A visual indication the valve is in the open position is when the stem is protruding approximately 1/4 inches above the cylinder.  If the stem is protruding visually 1/4 inch more than the stroke of the valve, this is an indication the valve is closed.

STANDARD WELLHEAD ACTUATORS

Pneumatic
AUP – Pneumatic Piston Actuator
AUD – Fail Safe Pneumatic Diaphragm Actuator
Axelson MHA – Pneumatic Actuator suited for higher pressures
Axelson MHA-1A – Pneumatic Actuator – pressures are 10K or less
Axelson AM-1A –  Pneumatic Actuator with built-in manual override

Hydraulic

actuator-accessoriesACTUATOR ACCESSORIES

  • Limit Switch (see information below)
  • Valve Position Indicator
  • Lockout Caps – Fusible and Standard
  • Transparent Stem Protectors
  • Mechanical Opening Assembly
  • Hydraulic Opening Assembly

Axelson Limit Switch or Proximity Switch for Actuator Applications

axelson-limit-switch

 

AUD AND AUP ACTUATOR APPLICATIONS

axelson-limit-switch-chart

axelson-limit-switch-position-indicator

 


 

Actuator Accessories

Limit Switch
Valve Position Indicator
Lockout Caps – Fusible Lockout Caps and Standard Lockout Caps – Fusible Lock Open Caps Axelson
Transparent Stem Protectors
Mechanical Opening Assembly
Hydraulic Opening Assembly

Natural Gas for Our Future
Natural Gas an ideal fuel source for many reasons, including safety. Natural Gas is lighter than air. This means that it will not puddle (like gasoline) or sink to the ground like propane, which is heavier than air. Instead, Natural Gas will rise and dissipate in the atmosphere. Natural gas also has a higher ignition temperature. This means that it is much harder to ignite. Also the storage systems used for compressed natural gas are infinitely stronger that the gasoline tanks found on cars and trucks today.
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CONTACT US

Toll Free: 1-877-244-4883
Fax: 412-257-8890
Phone: 412-257-8866

SHIPPING ADDRESS
P.C. McKenzie Company
1365 McLaughlin Run Road
Pittsburgh, PA 15241

MAILING ADDRESS
P.C. McKenzie Company
P.O. Box 112638
Pittsburgh, PA 15241

- P.C. McKenzie Company is located South of Pittsburgh, Pennsylvania -

P. C. McKenzie Company

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