The provided manual describes the ROTEX QTF Range Pneumatic Rack and Pinion Actuator, an industrial device designed for converting pneumatic pressure into rotational motion to operate valves.
Function Description
The QTF actuator operates on the principle of a rack and pinion mechanism. It utilizes compressed air to move pistons, which in turn engage with a pinion gear. This linear motion of the pistons is translated into rotational motion of the pinion, thereby providing the necessary torque to open or close a valve.
The actuator is available in two primary operating modes:
- Double Acting: In this mode, both ports (A and B) are used as inlet ports. When air is supplied to Port A, the pistons move away from each other, rotating the pinion counter-clockwise (CCW). When air is supplied to Port B, the pistons move closer, returning to their home position and rotating the pinion clockwise (CW). This mode requires air pressure for both opening and closing operations.
- Spring Return (Fail CW): In this configuration, Port A is the primary inlet. When air is supplied to Port A, the pistons move apart, compressing internal springs, and the pinion rotates CCW. When air is exhausted from Port A, the compressed springs return the pistons to their home position, rotating the pinion CW. This design ensures that the actuator returns to a safe, closed (CW) position in the event of air supply failure.
The actuator is designed for robust performance in various industrial applications, ensuring reliable valve operation.
Important Technical Specifications
The QTF range actuators are built to meet international standards and offer a range of sizes and configurations.
General Specifications:
- Mounting: In accordance with ISO 5211/DIN 3337/VDI/VDE 3845 (NAMUR), ensuring compatibility with a wide range of valves and accessories.
- Seal Material: NBR (Nitrile Butadiene Rubber) is the standard seal material, as indicated by "NBR" on the nameplate.
- Operating Temperature Range: Standard operating temperature is -20 °C to +80 °C (-4 °F to +176 °F). This range is crucial for ensuring the longevity and proper functioning of the seals and other components.
- Maximum Supply Pressure: The actuator should not be operated above 8 bars (116 psi or 8.1 kg/cm²). Exceeding this pressure limit can lead to damage.
- ATEX Compliance: The actuators are designed with ATEX considerations, and specific warnings regarding lifting and earthing are provided to prevent spark generation in hazardous environments. The label includes "II 2 GD T6" indicating its ATEX classification.
Speed Limitation Chart (for Single and Double Acting at 6 bar g):
The manual provides a speed limitation chart to ensure safe and optimal operation, especially in ATEX environments. Users are advised to use the slowest speed between ATEX limitations and ROTEX recommendations.
| Actuator Model |
Minimum Operating Time (seconds) (ATEX) |
Recommended Operating Time (seconds) (ROTEX) |
| QTF 32 |
0.02 |
0.3 |
| QTF 40 |
0.02 |
0.3 |
| QTF 50 |
0.02 |
0.3 |
| QTF 63 |
0.02 |
0.3 |
| QTF 80 |
0.03 |
0.4 |
| QTF 90 |
0.03 |
0.4 |
| QTF 100 |
0.03 |
0.6 |
| QTF 110 |
0.04 |
0.6 |
| QTF 125 |
0.04 |
0.6 |
| QTF 150 |
0.05 |
1.0 |
| QTF 175 |
0.06 |
1.0 |
| QTF 200 |
0.06 |
1.0 |
| QTF 250 |
0.09 |
1.5 |
| QTF 300 |
0.07 |
1.5 |
| QTF 350 |
0.09 |
2.0 |
The model designation on the label provides specific details:
- QTF: Actuator series.
- 50: Size of the actuator.
- E: Indicates a spring return actuator (absence implies double acting).
- 8: Spring set code (for spring return models).
Usage Features
Installation:
- Positioning: Rotex actuators can be mounted in any desired position, but aligning the centerline of the pneumatic actuator module along the pipeline is recommended.
- Lifting: For larger actuators (QTF 200 and above), lifting lugs are provided and should be used for lifting the actuator only, not the complete valve assembly.
- Air Supply: The air supply must be clean, free from contamination, filtered according to ISO 8573-1, and regulated not to exceed 8 bars. Undersized tubing or fittings can restrict flow, leading to reduced pressure and intermittent operation.
- Earthing: When installed on a valve, the valve should be properly earthed to discharge static charges, especially in ATEX environments.
- Fastening: Ensure proper tightening of fasteners and mounting accessories to prevent loosening during operation. The manual provides a torque table for different bolt sizes.
Setting (Stroke Adjustment):
- Actuators are factory set to 0 and 90 degrees.
- Stroke adjustment screws (5A and 5B) allow for fine-tuning of the travel.
- Over Travel (Close): Loosen nut #13 and rotate screw 5A counter-clockwise (CCW).
- Under Travel (Close): Loosen nut #13 and rotate screw 5A clockwise (CW).
- Over Travel (Open): Loosen nut #13 and rotate screw 5B counter-clockwise (CCW).
- Under Travel (Open): Loosen nut #13 and rotate screw 5B clockwise (CW).
- Minor adjustments can significantly impact travel, so careful setting is required. The manual includes a table showing the number of bolt revolutions required for a 1° pinion travel for different actuator sizes.
Operation:
- Once installed and set, the actuator is ready for operation.
- Ensure all pneumatic connections are secure and free from leaks.
- The quality of the actuation media (air) is critical for performance and longevity.
Maintenance Features
Recommended Servicing:
The manual outlines a clear maintenance schedule based on the number of operating cycles:
- 500,000 Cycles:
- Clean and apply grease to seals (#1/6/11/12/14/16).
- Clean and apply grease to rack (#3) and pinion (#2).
- 1,000,000 Cycles:
- Replace all plastic parts (#7/12/15/18) and rubber parts (#6/11/14/16/23).
- Inspect springs for rust or deformity and replace if necessary.
Lubrication:
- ROTEX recommends specific greases: "5140120004" for the rack and "5140120005" for seals.
- Grease should be applied with a soft brush.
- Only original ROTEX spare parts and recommended lubricants should be used.
Disassembly and Assembly:
- Safety First: Always disconnect the air supply and ensure the actuator is depressurized before any disassembly. For spring return actuators, ensure springs are de-energized.
- Clean Environment: Disassembly and assembly should be performed in a clean, indoor area free from dust and water.
- Spring Tension: Special caution is advised when removing end caps on spring return actuators due to spring tension. It is recommended to use a press to ensure safe release.
- Piston Removal: Never attempt to remove pistons using air pressure once end caps are off.
- Inspection: All parts should be thoroughly inspected for wear, stress cracking, pitting, and damage to threads or sealing surfaces. Damaged parts must be replaced with new, original ROTEX parts.
- Pinion Alignment: During assembly, proper alignment of the pinion dot with the body's top pad dots (two dots for CCW, single dot for CW) is critical for accurate piston assembly.
- Spring Assembly: For spring return actuators, the body should be in a vertical position during spring and end cap assembly to ensure proper alignment.
- Post-Assembly Check: After reassembly, the actuator should be stroked several times to confirm proper function and safety, and to check for air leakage.
Storage:
- When not in use, actuators should be stored in a sealed plastic bag within a cardboard box to protect against moisture and dust.
- Store in a dry place, free from water and dust, at temperatures between 4°C and 49°C (40°F and 120°F).
- Avoid areas where the actuator could be damaged by impact.
General Safety Notes:
- Keep hands and clothing away from valve ports and the actuator pinion.
- Never remove end caps when the actuator is pressurized.
- Actuators must be accurately sized for proper operation.
- Operating outside temperature or pressure limits will cause damage.
- No metal should fall on the actuator body to prevent spark generation.
- All accessories should have explosion protection or be intrinsically safe.
- Any deviation from the manual's warnings voids Rotex's responsibilities.
The manual emphasizes the importance of adhering to instructions for safe and effective use, and recommends contacting ROTEX or an authorized distributor for any technical assistance or detailed warranty information.
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