一、Introduction
1.1 What Is an ML Series Electric Valve Actuator?
The ML Series Electric Valve Actuator is an electric drive device designed for industrial valve operation and automation. It can be used for valve opening and closing, on-site adjustment, remote operation, and bus control.
The actuator is suitable for a variety of valves, including gate valves, globe valves, throttle valves, diaphragm valves, plunger valves, and sluice gates. With a suitable worm gear reducer, it can also be adapted for 90-degree rotary equipment such as ball valves, butterfly valves, and dampers.
1.2 Typical Industrial Applications
ML Series electric actuators are used in industrial automation systems where reliable valve operation and centralized control are required.
Typical industries include:
- Power generation
- Steel manufacturing
- Petrochemical
- Metallurgy
- Water treatment
- Paper production
1.3 Available Product Types
The ML Series is available in several functional configurations, including:
- Standard outdoor type
- Explosion-proof type
- Integrated type
- Smart non-intrusive bus control type
二、Main Features of the ML Series
2.1 Protection Performance
The ML Series is designed with dustproof, rainproof, and light corrosion-resistant construction.
Standard protection ratings include:
- IP65
- IP67
- Optional IP68 for special orders
2.2 Torque and Travel Protection
The actuator is equipped with both travel limit protection and overload torque protection.
This dual protection system helps prevent damage to the actuator and valve when the actuator reaches the preset valve position or encounters excessive resistance during operation.
2.3 Manual and Electric Operation
The ML Series uses a semi-automatic manual-electric switching mechanism.
During manual operation, the handwheel can be used to operate the valve. When electric operation is restored, the mechanism automatically returns to electric drive. This allows valve operation to continue even when electrical power is unavailable.
2.4 Valve Position Indication
The actuator can be equipped with a mechanical or LCD valve position indicator, depending on the configuration.
The indicator allows operators to check the valve opening position directly, while certain configurations also support remote valve position indication.
三、Actuator Structure and Working Principle
3.1 Main Components
The ML Series electric valve actuator is composed of six main parts:
- Motor
- Reducer
- Control mechanism
- Manual-electric switching mechanism
- Handwheel
- Electrical section
3.2 Motor and Reducer
The actuator uses an outdoor-type three-phase asynchronous motor.
The motor transmits power through a reducer consisting of gears and a worm wheel system, transferring the motor output to the actuator output shaft.
The standard motor is designed for short-time operation, with a rated continuous working time of 10 minutes.
3.3 Torque Control Mechanism
The torque control mechanism monitors the resistance acting on the actuator output shaft.
When the output torque reaches the preset value, the mechanism activates a microswitch, cuts off the motor power supply, and stops the actuator.
This helps protect the actuator and connected valve against excessive mechanical load.
3.4 Travel Control Mechanism
The travel control mechanism is used to control the opening and closing travel of the valve.
As the actuator moves toward the preset valve position, the internal gear and cam system activates the microswitch, stopping the motor when the required travel is reached.
四、ML Series Model Range
4.1 Available Models
The ML Series includes a wide torque range with multiple actuator sizes:
| Model | Rated Torque | Maximum Control Torque | Output Speed | Motor Power | Approx. Weight |
|---|---|---|---|---|---|
| ML05 | 50 N·m | 75 N·m | 18 r/min | 0.12 kW | 17 kg |
| ML11 | 100 N·m | 150 N·m | 18 r/min | 0.18 kW | 17.5 kg |
| ML16 | 150 N·m | 225 N·m | 18 r/min | 0.25 kW | 18 kg |
| ML21 | 200 N·m | 300 N·m | 18 r/min | 0.37 kW | 25 kg |
| ML31 | 300 N·m | 450 N·m | 18 r/min | 0.55 kW | 26 kg |
| ML47 | 450 N·m | 675 N·m | 24 / 36 r/min | 1.1 / 1.5 kW | 100 kg |
| ML62 | 600 N·m | 900 N·m | 24 / 36 r/min | 1.5 / 2.2 kW | 103 kg |
| ML93 | 900 N·m | 1350 N·m | 24 / 36 r/min | 2.2 / 3.0 kW | 128 kg |
| ML123 | 1200 N·m | 1800 N·m | 24 r/min | 3.0 kW | 132 kg |
| ML184 | 2500 N·m | 3000 N·m | 24 / 36 r/min | 4.0 / 5.5 kW | 245 kg |
| ML254 | 2500 N·m | 3000 N·m | 24 r/min | 5.5 kW | 250 kg |
| ML355 | 3500 N·m | 4200 N·m | 18 r/min | 7.5 kW | 450 kg |
| ML505 | 5000 N·m | 6000 N·m | 18 r/min | 10 kW | 460 kg |
The model range covers rated output torque from 50 N·m to 5000 N·m, allowing selection for different valve sizes and operating requirements.
五、Power Supply and Operating Conditions
5.1 Standard Power Supply
The standard ML Series power supply is:
- Three-phase 380 V
- ±10%
- 50 Hz
Special-order power options include:
- Three-phase 660 V
- Three-phase 415 V
- Single-phase 220 V / 60 Hz
5.2 Ambient Conditions
The standard operating conditions include:
- Relative humidity: up to 95% at 25°C
- Ambient temperature: -20°C to +60°C
- Special-order temperature range: -40°C to +100°C
5.3 Duty Cycle
The standard actuator uses a short-time working system with a continuous operating time of approximately 10 minutes.
A 30-minute duty option can also be supplied for special orders.
六、Control and Configuration Options
6.1 Functional Codes
The ML Series model coding system includes several configuration options:
- S — Standard
- E — Explosion-proof
- W — Integrated
- A — Adjustable
- I — Smart non-intrusive
- B — Bus control
- D — Special configuration
6.2 Control Functions
Available control function codes include:
- S — Standard
- F — 4–20 mA signal feedback
- R — Remote control
- K — Standard type with push buttons
- D — Special type
6.3 Output Speed Options
The model coding system provides several output speed selections:
- 12 r/min
- 18 r/min
- 24 r/min
- 36 r/min
- 48 r/min
- 72 r/min
七、Connection and Installation
7.1 Connection Types
The ML Series supports multiple connection arrangements, including:
- Flange connection
- Thrust connection
- Special connection configurations
7.2 Thrust-Type Flange Options
The thrust-type connection range includes:
- ML05 / ML11 / ML16 — F10
- ML21 / ML31 — F14
- ML47 / ML62 — F16
- ML93 / ML123 — F25
- ML184 / ML254 — F30
- ML355 / ML505 — F35
7.3 Installation Requirements
The actuator can be installed vertically or horizontally.
During installation, the actuator should be positioned to allow convenient wiring, commissioning, maintenance, and manual operation. The axial clearance between the actuator and valve connection should not be less than approximately 1–2 mm.
八、Commissioning and Adjustment
8.1 Torque Adjustment
Torque adjustment should begin from a lower setting and gradually increase until the valve closes correctly.
The required opening and closing torque should be adjusted according to the operating characteristics of the valve.
8.2 Travel Adjustment
The travel control mechanism should be adjusted separately for the closing and opening positions.
After adjustment, the actuator should be electrically operated several times to verify that the valve travel meets the required operating position.
8.3 Position Indicator Adjustment
The valve position indicator should be adjusted after the torque and travel settings have been completed.
The indicator and potentiometer are then matched to the actual valve opening position to provide accurate local or remote valve position indication.
九、Maintenance
9.1 Routine Inspection
For valves that are not frequently operated, regular inspection and operation are recommended.
The manufacturer recommends checking the actuator approximately once a month, with each test operation lasting no more than 10 minutes.
9.2 Service Life and Spare Parts
Under normal operating conditions, the actuator is generally designed for approximately 10,000 operations.
Available maintenance parts include:
- Microswitches
- Oil-resistant rubber seals
- Skeleton oil seals
- Springs
- Belleville springs
- Travel control mechanism
- Adjustable opening indicator
十、How to Select an ML Series Electric Actuator
10.1 Confirm the Required Torque
The actuator rated torque should be selected according to the valve operating torque.
The ML Series provides multiple models from 50 N·m to 5000 N·m, allowing the actuator size to be matched to the valve load.
10.2 Confirm Valve Type and Connection
The valve type, stem diameter, flange size, and connection arrangement should be confirmed before actuator selection.
For quarter-turn valves, a suitable worm gear reducer may be required.
10.3 Confirm Control Requirements
The required control mode should also be determined, such as:
- Standard operation
- Remote control
- 4–20 mA feedback
- Integrated control
- Smart non-intrusive control
- Bus control
- Explosion-proof configuration
10.4 Confirm Power Supply and Environment
Voltage, frequency, ambient temperature, humidity, protection rating, and explosion-proof requirements should be confirmed according to the installation environment.
十一、Conclusion
The ML Series Electric Valve Actuator provides a broad range of torque capacities and control configurations for industrial valve automation.
With models ranging from ML05 to ML505, rated torque from 50 N·m to 5000 N·m, manual-electric switching, travel and torque protection, multiple control options, and several connection configurations, the series can be selected for a wide range of industrial valve applications.
