The working principle of pneumatic valves
Time: 2023-11-18
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| Model representation | |
| WH→ Weiheng brand | —P22→ output shaft hole size→LD=Parallel bevel output hole H = parallel diagonal output hole W = two keyway output holes |
| —AT → pneumatic actuators | —10→ number of springs→ number of springs at both ends 5-12 |
| D→ size, size, action form→ actuator size, 52-300 action form D=double-acting, E = Single Acting (Spring Return) |
—HT→ operating temperature→ST=standard operating temperature, nitrile rubber O-rings -20Cto+80°C HT = high temperature fluoroelastomer O-ring -15Cto + 150°C LT = Low temperature silicone rubber O-ring -40°Cto +80°C |
| —090→ rotation angle → 90/120/180° 0°-90/0°-180° full stroke mechanical adjustment 3P-0°-45°-90/3P-0°-90°-180° three positions |
—A→ anti-corrosion grade→ anti-corrosion grade A, B |
| —F10→ connection size→ in accordance with international standard ISO5211 (F03-F25) | |
overview
- Rack and pinion double piston symmetrical structure design, fast and stable action, high precision, high output power, by simply changing the piston assembly position can get the opposite direction rotation.
- Extruded high-quality aluminum alloy cylinder block, hard anodized (anodized + Teflon coating in special cases) on the precision machined inner bore and outer surface, for longer service life and lower coefficient of friction.
- The one-piece design, with all double-acting and single-acting actuator models, has the same block and end cap, making it easy to change the mode of action by adding a spring or removing the spring.
- The combined preload safety spring set can easily and safely install or increase or decrease the number of springs during the assembly process or in the use site.
- The two separate adjusting screws on the outer side are more accurate and convenient for actuators that are already mounted on the valve, adjusting the opening and closing positions of the valve, and if full stroke adjustment is required, the additional two end caps are equipped with longer adjusting screws.
- Multi-function position indicator, visual indication on site, VDI/VDE3845, NAMUR standard slot, installation and output of all accessories such as limit switch box, electrical positioner, position sensor (Turck).
- The air supply connection is in accordance with NAMUR standards and can be directly installed with NAMUR standard solenoid valves.
- The composite bearings on the back of the rack, the piston guide rings, and the bearings of the output shaft prevent metal-to-metal friction and increase lubrication to ensure low friction and long life.
- All fasteners are made of stainless steel for long-term corrosion resistance.
- The connection part conforms to the new international standard specification ISO5211, and the DIN3337 (F03-F25) makes the product installation interchangeable and versatile.
Double-Acting Operating Principle (WHATD)
When the air source pressure enters the middle cavity between the two pistons of the cylinder from the air port (2), the two pistons are separated and move to the direction of the two ends of the cylinder, and the air of the air cavity at both ends is discharged through the air port (4), and the two piston racks are synchronously driven to rotate the output shaft (gear) in the counterclockwise direction. On the contrary, when the air source pressure enters the cylinder both ends of the air cavity from the air port (4), make the two pistons move to the middle direction of the cylinder, and the air of the middle air cavity is discharged through the air port (2), and make the two piston racks synchronously drive the output shaft (gear) to rotate in the clockwise direction simultaneously. (If the piston is mounted in opposite directions, the output shaft becomes reversed, which is a double-acting reverse rotation.) ）
Single-Acting Operating Principle (WHATD)
When the air source pressure enters the middle cavity between the two pistons of the cylinder from the air port (2), the two pistons are separated and move in the direction of the two ends of the cylinder, the springs at both ends are forced to compress, and the air of the air cavity at both ends is discharged through the air port (4), and the two piston racks are synchronously driven to rotate the output shaft (gear) in the counterclockwise direction simultaneously. After the air source pressure is reversed by the solenoid valve, the two pistons of the cylinder move to the middle direction under the elastic force of the spring, and the air of the middle air cavity is discharged from the air port (2), and the two piston racks are synchronously driven to drive the output shaft (gear) to rotate in the clockwise direction simultaneously. (If the piston is installed in the opposite direction, the output shaft becomes counter-rotating when the spring is returned, which is a single-acting reverse rotation)
Example of a double-acting actuator
Actuator selection
When selecting pneumatic actuators, the safety value is increased to the torque of the determined valve, and the safety value of water vapor or non-lubricated liquid medium is increased by 25%; 30% increase in safety value for non-lubricated slurry liquid media; The safety value of non-lubricated dry gas medium is increased by 40%; The safety value of granular powder medium conveyed by non-lubricating gas is increased by 60%; For clean, low-friction lubricating media, increase the safety value by 20% (the above safety value is the company's theoretical recommendation, for reference only).
Example of a double-acting actuator
When controlling a ball valve that requires torque of 200Nm, the air source pressure is only 5 bar, the medium is non-lubricated water vapor, taking into account the safety factor, increase the safety value by 25% is equal to 250Nm, find the air source pressure 5 bar according to the double-acting output torque table, and then vertically search for the torque data equal to or similar along the column, select 277Nm, look for its model along the line to the left, and select the WHAT1250D type.
Example of single-acting actuator selection
Example of single-acting actuator selection
When controlling a butterfly valve that requires torque of 100Nm, the air source pressure is 4.5bar, and the medium is a non-lubricated dry gas, considering the safety factor, increasing the safety value by 40% is equal to 140Nm, and finding the end point of the spring return according to the single-acting output torque table to obtain a similar torque of 148Nm, Then along the line to the left to find the end torque of the air source pressure 4.5bar 158Nm, must consider the relative force balance of the air source pressure torque and the spring return torque, and then along the line to the left to find its model and the number of springs, select WH140E type, 9 springs.
| Actuator-related data | |||||||||||
| Model | Maximum air pressure | Rotation angle | Operating Temperature (°C) | Stroke adjustment per 1° turns | Cylinder diameter Φ(mm) | Cylinder capacity (L) Open and closed | Switching Time (Seconds) (A) | WEIGHT (KG) (B) | |||
| Open direction | Guan Xiang | Each spring | |||||||||
| WHAT52 | Dry or lubricated clean compressed air 8 bar | 90°±4° or full stroke 0°~90° | ST (standard) nitrile rubber 0-ring -20~80 HT (High Temperature) Viton 0-Ring -15-150 LT (low temperature) silicone rubber O-ring -40~80 |
1/6 | 52 | 0.1 | 0.2 | D0.2 | D0.3 | D1.1 | |
| E0.3 | E0.3 | E1.2 | 0.01 | ||||||||
| WHAT63 | 1/6 | 63 | 0.2 | 0.3 | D0.3 | D0.3 | D1.6 | ||||
| E0.3 | E0.4 | E1.8 | 0.02 | ||||||||
| WHAT75 | 1/5 | 75 | 0.3 | 0.5 | D0.3 | D0.4 | D2.8 | ||||
| E0.4 | E0.5 | E3.2 | 0.02 | ||||||||
| WHAT83 | 1/5 | 83 | 0.5 | 0.8 | D0.4 | D0.5 | D4.0 | ||||
| E0.5 | E0.6 | E4.7 | 0.06 | ||||||||
| WHAT92 | 1/5 | 92 | 0.7 | 1.1 | D0.5 | D0.6 | D5.9 | ||||
| E0.7 | E0.9 | E6.7 | 0.07 | ||||||||
| WHAT105 | 1/5 | 105 | 1.2 | 1.8 | D0.7 | D0.8 | D8.5 | ||||
| E0.9 | D0.8 | E10.0 | 0.13 | ||||||||
| WHAT125 | 1/4 | 125 | 1.5 | 2.3 | D0.9 | D1.1 | D10.7 | ||||
| E1.2 | E1.4 | E12.5 | 0.16 | ||||||||
| WHAT140 | 1/4 | 140 | 2.4 | 3.8 | D1.2 | D1.4 | D15.5 | ||||
| E1.5 | E1.8 | E18.3 | 0.55 | ||||||||
| WHAT160 | 1/4 | 160 | 3.1 | 4.9 | D1.5 | D1.7 | D19.5 | ||||
| E1.8 | E2.1 | E23.3 | 0.36 | ||||||||
| WHAT190 | 1/4 | 190 | 4.3 | 6.9 | D2.0 | D2.2 | D26.7 | ||||
| E2.4 | E2.8 | E32.8 | 0.5 | ||||||||
| WHAT210 | 1/4 | 210 | 5.9 | 9.5 | D2.7 | D3.2 | D35.6 | ||||
| E3.5 | E4.0 | E43.6 | 0.62 | ||||||||
| WHAT240 | 1/4 | 240 | 10 | 15.2 | D3.5 | D4.0 | D58.7 | ||||
| E4.1 | E4.6 | E71.0 | 1.12 | ||||||||
| WHAT270 | 1/4 | 270 | 14 1/2 | 21 2/5 | D4.0 | D4.5 | D78.8 | ||||
| E4.5 | E5.0 | E96.5 | 1.56 | ||||||||
| WHAT300 | 1/4 | 300 | 25 | 40 | D6.0 | D7.0 | D130 | ||||
| E7.5 | E8.5 | E163 | 2.95 | ||||||||
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