The LRP actuator drive shaft rotates through a full 90° segment with approximately 3° overtravel at each end of travel. Rotation is accomplished by feeding supply air into the center chamber, forcing the two opposing pistons apart, resulting in a counter-clockwise rotation of the drive shaft to the “open” position. For double-acting actuators, closure is obtained by feeding supply air into the end cap chambers, which forces the pistons together, resulting in a clockwise rotation of the drive pinion. For spring-return actuators, closure is accomplished by means of springs contained within the end caps which force the pistons together when the supply air to the center chamber has been interrupted. If rotation opposite to that described above is required, refer to the section on Installation for the proper procedure to reverse the rotation.
The accurate rotation of the actuator pinion is controlled through the adjustment of two hexagon headed bolts on the end cap. Each bolt will control either the open or closing stroke (based on how the actuator has been orientated on the valve). The adjustment of each bolt is shown on the end cap. Actuators are factory set to provide a 90 ̊ operation. If adjustment needs to be made the lock nut will need to be backed off, the adjustment screw rotated to provide correct positioning and the lock nut retightened. For size 10 to 35 turn screw clockwise to decrease rotation and counterclockwise to increase rotation. For size 40 the reverse applies. It is critical to retighten to ensure an effective seal of thewasher. Care should be taken to secure
travel stop setting when tightening lock nut.
• Balanced double rack and pinion provides a linear torque curve with a large range of sizes for efficient torque matching
• Mounting to ISO 5211 pattern and DIN 3337 female star drive provides common and simple actuator to valve attachment
• Position indicator – provides highly visible external indication of valve position
• Foolproof location pin for correct assembly
• Multi-spring concept – allows variable torque/air pressure requirements from the same actuator by changing spring quantity
• Namur VDI/VDE 3845 top mounting pattern – for easy fitting and interchangeability of switches, positioners, etc
• Namur VDI/VDE 3845 end-cap solenoid mounting pattern – facilitates interchangeability of solenoids or direct port connections
• Compact fail-safe size as per double-acting – minimizes space requirements
Reduced maintenance and Longer Service life
• Anodised aluminium construction – for anti-corrosion and superior wear performance on internal surfaces, plus stainless steel fasteners and corrosion-protected springs
• One piece steel pinion drive with full width piston tooth engagement – for greater operational life
Increased plant and personnel safety
• For fail-safe operation in a fire, polished support rods retain fire-safe capability even if bearings are fire damaged
• Blow-out proof pinion – eliminates risk of pinion ejection even after pinion retaining ring is removed
• Unique unrestricted air flow through support rods gives fast operation speeds as standard – and also provides greater safety (center chamber cannot be pressurized with end cap removed)
• Long end cap screws allow complete release of spring energy for safe removal of end caps.