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Part-turn
A Part-turn actuator is an actuator which transmits torque to the valve for less than one revolution.
It does not have to be capable of withstanding thrust.
A combination of a multi-turn actuator plus a part-turn gearbox can also be considered as a part-turn actuator.Associated valves
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Butterfly valves
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Ball and plug valves
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Dampers and louvers
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Other valves
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Multi-turn
A Multi-turn actuator is an actuator which transmits torque to the valve/gearbox for at least one revolution.
It may be capable of withstanding thrust.
A combination of a multi-turn actuator plus a multi-turn gearbox can also be considered as a multi-turn actuator.-
Globe valves
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Knife gate valves
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Gate and wedge gate valves
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Penstock valves
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Other valves
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Linear
A Linear Actuator is an actuator which transmits thrust to the valve for a defined linear stroke.
A combination of a multi-turn actuator plus a linear drive can be considered as a linear actuator.-
Globe valves
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Other valves
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IP / NEMA Weatherproof enclosures
- EN60529 Standard defines IP indicator to specify the weatherproofness of a device. First digit refers to protection against solid objects: number 6 corresponds to dust tightness. Second digit refers to protection against moisture/watertightness. Electric actuators are not designed for permanent water submersion; however, temporary immersion is possible from IP67 upwards.
- IP65: Protected against water jets
- IP67: Protected against the effects of immersion (max. 1m deep & 30 min long)
- IP68: Protected against submersion (time lapse & depth to be specified,
ex: 5m/72h or 10m/96h) - American Standard NEMA proposes another classification for actuator weatherproof enclosure protection: NEMA 4, 6, 6P and 6X according to working environment, up to protection against submersion.
- EN60529 Standard defines IP indicator to specify the weatherproofness of a device. First digit refers to protection against solid objects: number 6 corresponds to dust tightness. Second digit refers to protection against moisture/watertightness. Electric actuators are not designed for permanent water submersion; however, temporary immersion is possible from IP67 upwards.
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Protection for explosive atmosphere
- Electric actuators working in explosive atmosphere require a specific enclosure protection submitted to dedicated certification.
- According to market areas, there exists several types of explosion proof certifications:
- European ATEX
- International IECEx
- US NEMA 7 & 9
- Customs Union for Belarus, Kazakhstan and Russia
- INMETRO for Brazil
- CQST for China...
Focus on ATEX European Directive
The European directive 94/9/CE states the conditions to be met for equipment items used under potentially explosive atmosphere. It classifies the installation areas according to groups and categories:
Ex de
OR
Equipment with electric connection in increased safety "e" (tight terminal box). The remaining parts of the electric equipment are in explosion proof "d" enclosure.
Explosion proof actuator. Ex de
Ex d
Protection by explosion proof enclosure. Connection is achieved inside the enclosure. Enclosure is resistant to internal explosion without flame path.
Explosion proof actuator. Ex d
II B
Group I : Equipment for underground mining.
Group II : Equipment for explosive atmosphere other than mining.A: butane, propane,...
B: ethylene,...
C: hydrogen, acetyleneT4
Maximum surface temperature.
T1 = 450 °C
T2 = 300 °C
T3 = 200 °C
T4 = 135 °C
T5 = 100 °C
T6 = 85 °COur explosion proof products have been designed for use in GROUP II, Category 2 G (D) areas.
These products shall, among other requirements, undergo a CE type examination corresponding to the sections of the CENELEC standards EN 60079, 61241, 13463 applicable for each product.
BERNARD CONTROLS can offer different levels of protection such as : Ex de, Ex d, IIB, IIC, T4, T5, T6.Focus on North American standards: NEMA ratings
NEMA
Class
Group
Division
T
7
I
Combustible
gases and vapoursGroup B: Hydrogen
Group C: Ether, Ethylene,...
Group D: Butane, Propane,...1
Normal conditionsMaximum surface temperature.
9
II
Combustible dustsGroup E: Metal dust
Group F: Coal dust
Group G: Flour and other dusts2
Abnormal conditionsT1 = 842 °F
T2 = 572 °F
T3 = 392 °F
T4 = 275 °F
T5 = 212 °F
T6 = 185 °FExplosion proof actuator NEMA 7 or NEMA 9
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Cx : Corrosion standard
In addition to weatherproofness level which determines actuator enclosure protection, corrosion level specifies painting type of the actuator. Corrosion level is defined in ISO12944-2 standard and goes from C2 (weak) to C4 (high) and C5 (very high, either C5-I for Industrial areas with high humidity and aggressive atmospheres or C5-M for marine/coastal areas with high salinity).
Environmental corrosion categories
Corrosion category
Typical environments
Exterior
Interior
C2 (low)
Atmospheres with low level of pollution.
Mostly rural areas.Unheated buildings where condensation may occur, e.g. depots, sport halls.
C3 (medium)
Urban and industrial atmospheres, moderate sulphur dioxide pollution.
Coastal areas with low salinity.Production rooms with high humidity and some air pollution, e.g. food-processing plants, laundries, breweries.
C4 (high)
Industrial areas and coastal areas with moderate salinity.
Chemical plants, swimming pools, coastal shipyards.
C5-I (very high - industrial)
Industrial areas with high humidity and aggressive atmosphere.
Buildings or areas with almost permanent condensation and with high pollution.
C5-M (very high-marine)
Coastal and offshore areas with high salinity.
Buildings or areas with almost permanent condensation and with high pollution.
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Nuclear site
- Nuclear Power Plants required special design of actuators which are qualified according to RCC-E or IEEE safety standards and can be installed either inside or outside containment area.
- The RCC-E and IEEE documents specify the rules for design, qualification and construction of electrical materials for nuclear power plants.
- Three main levels of requirements and qualification exist depending on the type of application. Please note that these three types of application exist in all standards but may be named differently.
- The three levels of requirements are :
- Non safety requirements (NC) : actuators designed for operation in normal environment for 30 years (referred as "NC" type in the RCC-E standard)
- Safety requirements outside containment (Nuc OC) : actuators designed for operation in normal environment for 30 years and during seismic accidents (referred as "K3" type in the RCC-E standard)
- Safety requirements inside containment (Nuc IC) : actuators designed for operation during 40 years in ionizing environment and remaining operational in case of seismic accidents and LOCA, Loss of Coolant Accident (referred as "K1" type in the RCC-E standard)
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Classification Standard EN15714-2
ON-OFF
Standard Duty Class ATorque
NmDuty performance
cycles per hourEndurance
number of cycles<126
15
10 000
126 à 1000
10
10 000
1001 à 4000
5
5 000
4001 à 32 000
5
2 500
>32000
5
1 000
INCHING / POSITIONING
Standard Duty Class BTorque
NmDuty performance
starts per hourEndurance
number of cycles<126
120
10 000
126 à 1000
60
10 000
1001 à 4000
30
5 000
4001 à 32 000
15
2 500
>32000
5
1 000
MODULATING
Standard Duty Class CTorque
NmDuty performance
starts per hourEndurance
number of starts<126 1 200 1 800 000
126 à 1000
600
1 200 000
1001 à 4000 300 500 000
4001 à 32 000
60
250 000
>32000 30 T.B.A
CONTINUOUS MODULATING
Standard Duty Class DTorque
NmDuty performance
starts per hourEndurance
number of starts<126 3 600 10 000 000
126 à 1000
1 800
10 000 000
1001 à 4000 600 5 000 000
4001 à 32 000
N.A.
T.B.A
>32000 N.A. T.B.A
ON-OFF
Standard Duty Class ATorque
NmDuty Performance
running time per hourEndurance
number of cycles<101 15 10 000
101 à 700
15
10 000
701 à 2 500 15 5 000
2501 à 10 000
15
2 500
>10 000 15 1 000
INCHING / POSITIONING
Standard Duty Class BTorque
NmDuty performance
starts per hourEndurance
number of cycles<101 30 10 000
101 à 700
20
10 000
701 à 2 500 15 5 000
2501 à 10 000
10
2 500
>10 000 5 1 000
MODULATING
Standard Duty Class CTorque
NmDuty performance
starts per hourEndurance
number of starts<101 1 200 1 800 000
101 à 700
600
1 200 000
701 à 2 500 300 500 000
2501 à 10 000
60
250 000
>10 000 30 T.B.A
CONTINUOUS MODULATING
Standard Duty Class DTorque
NmDuty performance
starts per hourEndurance
number of starts<101 3 600 10 000 000
101 à 700
1 800
10 000 000
701 à 2 500 600 5 000 000
2501 à 10 000
N.A.
T.B.A
>10 000 N.A. T.B.A
ON-OFF
Standard Duty Class AThrust
kNDuty performance
running time per hourEndurance
number of cycles<21 15 10 000
21 à 70
10
10 000
71 à 150 5 5 000
151 à 325
5
2 500
>325 5 1 000
INCHING / POSITIONING
Standard Duty Class BThrust
kNDuty performance
starts per hourEndurance
number of cycles<21 30 10 000
21 à 70
15
10 000
71 à 150 10 5 000
151 à 325
10
2 500
>325 10 1 000
MODULATING
Standard Duty Class CThrust
kNDuty performance
starts per hourEndurance
number of starts<21 1 200 1 800 000
21 à 70
600
1 200 000
71 à 150 300 500 000
151 à 325
60
250 000
>325 30 T.B.A
CONTINUOUS MODULATING
Standard Duty Class DThrust
kNDuty performance
starts per hourEndurance
number of starts<21 3 600 10 000 000
21 à 70
1 800
10 000 000
71 à 150 T.B.A 5 000 000
151 à 325
T.B.A
T.B.A
>325 T.B.A T.B.A
- Modulating performance criteria
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Resolution
- The resolution is the smallest achievable step at the output shaft of the electric actuator.
- This is the most important performance criterion to ensure efficient modulating since it refers to the ability of the actuator to promptly operate the valve by little steps.
- Practically, if we have a minimum output change - resolution - equals to 2%, then:
- 2% means 2% of the total travel of the valve.
- Therefore, a resolution of 2% allows the actuator to reach 50 steps along the total travel. Similarly a resolution of 1% would allow the actuator to reach 100 steps along the total travel.
- For a Quarter-turn actuator: 2% of 90°= 1,8°(minimum output change would be a rotation of 1,8°)
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Dead band
- The dead band is the range through which an input signal may vary, upon reversal of direction, without triggering any observable change in the position of the valve
- For example, a dead band of ±1% means that, if the actuator receives the order to move to position x, it must finally stop within an interval of
[x-1%; x+1%] - Obviously, an actuator with a dead band of 1% will be more performant for modulating than an actuator with a dead band of 2%
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Response time
- The response time is the time needed by the actuator to reach the required position following an input signal change.
- Usually, the electric actuator piloting a valve must reach a specific position as quick as possible to ensure an optimal control of the process. This is even more relevant when it comes to small changes of valve position. Therefore, response time is a key performance criterion.
- In order to measure the level of performance of an actuator regarding response time, we usually compare « T63 ».
- T63 is the lapse of time needed by the actuator to reach 63% of the output step when it receives an input signal of 2%. This a reference time measurement called time constant.
- The response time is the addition of the dead time (time without any movement) and time constant T63.
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Linearity
- The linearity refers to the idea that the percentage of change in input signal must approximate the percentage of change at the output of the actuator.
- Indeed, a valve is called linear when the flow is proportional to the opening position of the gate.
- Most of modulating valves are linear. But depending on the type of valve, linearity may vary.
- In case of strong non-linearity of the valve, it may cause instability of the modulating process. Therefore, the valve must be operated only through its most linear portion to ensure modulating duty.
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What is Fail Safe ?
For all part-turn applications, spring return FQ range actuators ensure the immediate and automatic opening or closing of the valve even without any power supply, as soons as an emergency signal is activated.
This signal can be activated following:
- an abnormal event (fire, overflow ...)
- an automatic control
- an operator's action
- or the lack of power supply
Examples of applications: storage and distribution of gas and dangerous liquids, fire protection systems, protection of chemical facilities, air conditioning and ventilation of hazardous areas.
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SWITCH
Electromechanical control
The control unit is designed by the customer and located in a remote cabinet.
All information sent by the actuator sensors (travel limit, torque limit, thermal overload, position feedback, ...) have to be processed by user's control logic. -
INTEGRATED
Control integrated to the actuator
The control unit and power contactors are an integrated part of the actuators. It executes orders from the supervisor. In addition, it offers local controls that can be disabled locally or remotely. It can also be managed by fieldbus.Bernard controls offers the “LOGIC” integrated control on the new ranges (INTEGRAL on the former ones). This new control includes the main features expected from modern integrated control. To learn more about this new control, visit our website.
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INTELLI+ ®
Intelligent control
The INTELLI+® control allows easy commissioning thanks to its user friendly interface and the non-intrusive setting.
Numerous functions are available to the users helping them in their diagnostics and to schedule their valve maintenace operations. INTELLI+® also guarantees to the users an optimum availability of their industrial facilities. -
BC app’
Bernard controls is launches a unique mobile application that enables you to set-up and operate your valve in a few clicks. The app’ improves the reliability of your process thanks to valve activity data’ collection and keys features for your preventive maintenance plan.
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