Grassland specific intelligent switch electric actuator with altitude ≥ 4500m

Grassland specific intelligent switch electric actuator with altitude ≥ 4500m

Grassland specific intelligent switch electric actuator with altitude ≥ 4500m1. Overview

1) The electric actuator is a driving device with a two position 90 ° rotation control. This project uses intelligent electric actuators. The supplier should be responsible for the correct operation and model selection of the electric actuator. The selection of stroke/torque for any given valve's electric actuator depends on:

Valve and stem dimensions

Valve type environmental temperature

Maximum ground temperature

Maximum working torque of valve

The maximum torque that the valve can withstand

The full stroke time of the valve

The maximum working torque and maximum bearing torque of the selected valve should be obtained from the valve supplier.

Valves and couplings should be able to withstand the maximum torque generated by electric actuators.

The connecting sleeve between the actuator and the valve is provided by the actuator manufacturer.

The supplier of the actuator shall provide the rated torque and maximum stalling torque of the electric actuator.

The actuator should be selected according to the operating conditions under which the valve operates.

The overall assembly of the actuator should be sealed and suitable for outdoor operation.

2) The selection of electric actuators should meet the valve operation requirements under the operating conditions specified in the technical documents of this project, and the torque of the electric actuators should adopt a torque coefficient of 1.5 times.

3) When the diameter of the electric actuator is ≥ DN400, the fully open/close time must be ≤ 60s; when the diameter of the ball valve is ＜ DN400, the fully open/close time must be ≤ 30s, and the fully open/close time of the inlet and outlet buried shut-off valve actuator must be ≤ 45s.

4) The maximum torque of the actuator should be less than the maximum bearing torque of the valve, and the minimum torque should be greater than the maximum working torque of the valve. The output torque of the valve should be adjustable on site.

5) The electric actuator should be intelligent, double sealed, non-invasive, and integrated. Any external adjustment, debugging, fault diagnosis, and modification of the set value of the actuator can be carried out through external operations without the need to open the sealed end cover of the actuator. The motor starter should be inside the actuator. The surface of the actuator should have a durable anti-corrosion and UV resistant paint layer.

6) The intelligent electric actuator has an automatic inspection function after each power on, and the inspection time should be less than 25 seconds to ensure the normal operation of the equipment. At the same time, intelligent actuators have data and event recording functions, which can securely download and upload data in real-time within the explosion-proof area.

7) The supplier shall ensure that the normal service life of the electric actuator provided is not less than 30 years.

8) When the control system of the valve is damaged, it should not affect the manual operation of the valve. And the maintenance and replacement work of the actuator does not affect the valve position status.

9) The actuator and valve should be supplied as a whole after assembly, and the upper and lower limits and position limit switches of the actuator have been set up in the factory. The overall assembly and commissioning of the actuator and valve shall be completed by the valve manufacturer.

10) The power supply for the actuator should prioritize 380VAC, 50Hz, three-phase AC power supply, and the voltage withstand level of its internal electrical components and assemblies should not be lower than 500VAC.

11) The motor should be enclosed as a whole and cooled naturally. At the same time, it has "H" level insulation, which can meet the climatic conditions of the stations along the line.

12) The actuator should prevent the generation of condensate. The protection level of the motor should not be lower than IP68, and the explosion-proof level of the electrical enclosure should not be lower than Exd Ⅱ BT4Gb, and it should have certification from an authorized laboratory.

13) The terminal block connected to the outside should be placed in a sealed junction box. When connecting cables on site, the internal control circuit should be isolated from the outside (i.e. secondary sealed). There should be a wiring diagram inside the junction box, and the wiring terminals should be clearly marked. There should be grounding terminals inside and outside the junction box.

14) The junction box should be equipped with 3 cable connection holes (2 of which are 1 "NPT (F) holes and 1 is 1.5" NPT (F) hole), and each hole should be sealed with a metal plug. The installation direction of the holes must not face upwards.

2 Mechanical characteristics

1) The actuator should include a motor, gear reduction mechanism, coupling, valve position sensor, torque sensor, handwheel, handwheel automatic disconnection device, and junction box. The overall assembly of the actuator should be sealed and suitable for outdoor use, and meet the environmental requirements outlined in Part II of this specification.

2) The gears of the actuator should be lubricated with lubricating oil or grease, and the supplier should provide the brand and main indicators of the lubricating oil (grease) used. For stations with lower ambient temperatures, heaters should be considered, but adding heaters cannot lower the explosion-proof rating of the actuator. The lubrication system should have maintenance free performance.

3) A handwheel device should be installed at a location on the actuator that is convenient for manual operation, and it should be ensured that handwheel operation is still easy at maximum differential pressure. The rotation of the handwheel should be clockwise to close, and there should be an on/off arrow indication on the handwheel. During the operation of the handwheel, the maximum operating force should not exceed 250N.

4) During on-site manual operation, the motor is disengaged through the clutch of the manual and electric switching devices.

5) At a distance of 1m from the actuator, the noise level generated by the actuator cannot exceed 75dB.

6) The motor should have an overheat protection device. When the valve can still be opened even if it is partially stuck, the short-term stalling torque of the motor should be able to reach twice the rated torque. At the same time, the locked torque output by the actuator should not cause damage to the gearbox.

3. Characteristics of shut-off valve

1) The motor should be a squirrel cage induction motor. The voltage fluctuation of the power supply is ± 10%, and the frequency is ± 4%.

2) Under normal operation and rated voltage conditions, the temperature of any part of the motor shall not exceed 135 ℃.

3) The electric actuator is of the switch type.

4) The valve position signal output should be a passive contact, and the contact capacity should not be less than 1A24VDC.

5) The standard configuration of the actuator should have programmable 6 single pole single throw and 1 single pole double throw contacts

4. Characteristics of regulating valve

1) The internal control circuit power supply of the actuator is DC 24V, which can be provided by the electric actuator itself.

2) The actuator receives a 4-20mADC analog control signal from the control system, automatically adjusts the valve opening based on the signal, and can output a 4-20mADC valve opening feedback signal.

3) The accuracy of the internal controller of the electric actuator should be higher than ± 1%, and the maximum signal change required to make the electric actuator operate in the same direction should be ± 1.0%.

4) The valve position indication of the electric actuator should be continuous, with an increasing amount of 1%.