WENK Pneumatic AT Pneumatic Actuator

1. Product Introduction

The AT series pneumatic actuator is a new generation of rack and pinion pneumatic actuator developed by WENK Pneumatic. It is designed by comprehensively applying new technologies, new materials, new processes and innovative concepts from home and abroad. The product is divided into two types: double-acting and single-acting (spring return), suitable for switching and regulating control of quarter-turn control valves (such as ball valves, butterfly valves), and can also be used in other occasions requiring rotary motion.

The AT pneumatic actuator has the following features:

• Extruded aluminum alloy cylinder, hardened anodized treatment, hard surface, strong wear resistance
• Compact double piston gear and rack structure, precise meshing, smooth transmission, symmetrical installation position, constant output torque
• Piston, rack and output shaft moving parts are installed with F4 guide rings to achieve low friction, long life, avoiding metal-to-metal contact
• Cylinder, end cover, output shaft, spring, fasteners, etc. are all anti-corrosion treated
• The spring of single-acting actuator is installed after pre-compression, which can be safely and conveniently disassembled and assembled
• Two-way stroke adjustment of 0° and 90° ±5° can be performed at both fully open and fully closed positions
• The installation connection size complies with ISO5211, DIN3337, VDI/VDE3845 and NAMUR standards, ensuring interchangeability between actuators and convenient installation of solenoid valves, limit switches and other accessories

3. Installation and Commissioning

Preparation before Installation

1. Confirm that the actuator model matches the valve, and check if the actuator appearance is intact
2. Prepare necessary installation tools and accessories, including connecting bolts, nuts, etc.
3. Ensure the installation environment meets the working conditions of the actuator
4. Check if the compressed air system is clean, dry, and the pressure meets the requirements

Installation Steps

1. The pneumatic actuator can be directly connected to the valve, or can be installed and connected through brackets and joints. The connecting fasteners must not be loose
2. Ensure the coaxiality of the actuator output shaft and valve stem installation, and rotate flexibly without crawling
3. Connecting pipes, joints, accessories, etc. should be clean
4. The exhaust port of the solenoid valve should always face downward. When facing upward or horizontally, a elbow should be connected to make the exhaust port face downward
5. The installation connection size complies with ISO5211 standard to ensure interchangeability and versatility

Commissioning Method

1. Before commissioning, confirm that the air pipeline is unobstructed, and the air pressure, voltage, signal, etc. meet the requirements
2. Compressed air should be filtered, dried, and dehumidified when the dew point is below -15°C
3. The solenoid valve should be set to automatic position during commissioning
4. When operating pneumatically, the manual device should be disconnected; when operating manually, the pneumatic device should be disconnected
5. Various accessories installed on the actuator should be debugged with reference to the instruction manual
6. The valve opening and closing positions can be precisely adjusted through two separate adjustment screws on the external side. For full stroke adjustment, longer adjustment screws are configured at the two end covers

5. Troubleshooting

Pneumatic Valve Cannot Act

1. Check if the solenoid valve is normal, if the coil is burned out, or if the solenoid valve core is stuck by dirt

   • Solution: Replace the solenoid valve, replace the coil, remove dirt

2. Check if the actuator cylinder piston is leaking, or if there is air leakage at the cylinder body and end cover or rotating shaft

   • Solution: Disassemble the actuator to check if the seals are damaged, if the cylinder inner hole surface is damaged, replace the damaged seals, replace the cylinder or piston

3. Check if there are impurities in the valve that jam the ball core

   • Solution: Remove impurities and replace damaged valve parts

4. Check if the handle of the manual operating mechanism is in the manual position

   • Solution: Move the handle to the pneumatic automatic position

5. Check if the pipeline is twisted or flattened

   • Solution: Correct or replace the pipeline

6. Check if the medium or ambient temperature is too low, causing the pipeline to freeze

   • Solution: Timely remove condensate water, add water removal equipment

Pneumatic Valve Acts Slowly or Crawls

1. Insufficient air source pressure

   • Solution: Increase air source pressure, set up air storage tanks on the way to reduce pressure fluctuations

2. Insufficient flow or other devices with large air consumption working at the same time

   • Solution: Add air storage tanks, add air compressors to reduce pressure fluctuations

3. Pneumatic actuator torque is too small

   • Solution: Increase the size of AT pneumatic actuator

4. Valve load is too large, valve core or other valve parts are assembled too tightly and unreasonably

   • Solution: Re-fit and adjust valve torque

5. Cylinder friction changes greatly

   • Solution: Perform appropriate lubrication

Other Faults

1. Valve action starts to jump, load is too large

   • Solution: Increase the size of AT pneumatic actuator

2. Valve action jumps at the end, action is too fast, inertial energy is too large

   • Solution: Add speed control valve or external buffer

3. No signal from positioner

   • Solution: Repair power line, readjust cam to correct position, replace micro switch