Weak current College】 【valve electric device.

<br> <br> Valve electric device electricactuator driven hoist or control valve gate device. <br> Valve electric device is the realization of the program-controlled, automatic control valves and remote-controlled indispensable driving device, its movement by stroke, torque .or axial thrust of size to control. Because valve electric device characteristics and utilization of the work depends on the type of valve, installation work specifications and valve in the pipeline or location on the device. <br> General Electric appliance consists of the following parts .<br> First, private motor, characterized by overload ability is strong, starting torque, rotational inertia small, short-term, intermittent work <br> Second, the reduction gear to reduce motor output speed <br> 3. stroke control agency to .regulate and accurate control valve open and close position <br> 4. torque limiting bodies to regulate torque (or thrust) and not exceeding the predetermined value <br> 5. manual or electric switch bodies, for manual or electric operation of interlocking institutions < .br> 6. opening of the indicator, which shows the valves in the process of opening and closing the position <br> <br> And compared to other valve drive unit, electric drive unit with a power source, operation quickly, convenient, and .easy to meet a variety of control requirements. Therefore, in the valve drive, the electric appliance. <br> ◆ Valve electric device as input into Rotary-type (Z) and part of the Rotary type (Q-type), the former .is used for lifting lever valves, including: gate valve, globe valve, throttle valves, diaphragm valve and so on; the latter is used for Rotary lever valves, including ball valve, plug valve, butterfly valve and so on, usually in the 900 .range and close. <br> Valve electric device type as protection is divided into ordinary and special protective type two categories <br> ◆ Ordinary electric devices use environment as follows: <br> 1. ambient temperature: -25 ~ 40 ¡ .æ <br> 2, the ambient relative temperature ≤ 90% (25 ° c) <br> 3. altitude ≤ 1000m <br> 4. working environment requirements do not contain corrosive, flammable, explosive media <br> ◆ If valve working .environment conditions than ordinary electric device has the ability, use exceptional protection product, such product depending on the work environment and have a case type <br> <br> Special protection of electric device main technical characteristics <br> Type main features <br> .Outdoor-1, environment temperature: -40 ~ 40 ¡ .æ <br> 2, maximum rainfall: 50mm/10min <br> 3, the maximum intensity of solar radiation: 1.4J / (cm2 · min) <br> 4, sand, snow, Frost, dew <br> High temperature type .the highest ambient temperature up to 80 ° c <br> Minimum ambient temperature low temperature-to-55 c <br> Anti-corrosion type has one or more containing a certain concentration of environmental chemistry corrosive media <br> High speed shaft rotational speed .up to 70r/min <br> Explosion-proof should be on explosive media work <br> Ship type applies to vessels on the water or salt present environment <br> Fire-resistant type should be able to fire (eg temperatures up to 1300 .° c) environment, in a certain time (eg 15min) range still normal to open or close <br> Two-speed-type two-speed range up to 60: 1 <br> Diving-water resistant type suitable for short-time .immersed in the work environment (10mm, 72h); water resistant type ⅱ is suitable for long-term immersion depth of the work environment can be greater than 10m <br> Radiation protection-apply to the special requirements of occasions of nuclear power plants < .br> <br> Protection type code <br> Code protection type <br> B explosion-proof <br> R-resistant type <br> BWF outdoor, anti-corrosion, explosion-proof <br> <br> Valve electric device .is the realization of the program-controlled, automatic control valves and remote control of the necessary equipment, its movement by stroke, torque or axial thrust of size to control. Because valve electric device characteristics and utilization of the work depends on the type of valve ., installation work specifications and valve in the pipeline or location on the device, therefore, the correct choice valve electric device, to prevent overload phenomena (working torque than control torque) is essential. Typically, proper selection of valve electric device basis as follows: .<br> <br> Operating torque: operating moment is select valve electric device for the main parameter output torque of the electric device for valve operation maximum torque of 1.2 ~ 1.5 times. <br> Operation of the thrust: valve electric device host structure .has two kinds: one is not configured, the thrust plate directly output torque; the other is to configure the output torque thrust plate, plate by thrust of stem nut converted to output thrust. <br> Output shaft rotating coils: valve electric device output .shaft rotating coils of how much the valve of nominal diameter, valve stem pitch, thread heads, to press M = H / ZS calculation (M-electric devices should meet the total number of rotating ring, h is the height of valve opening, S .-stem drive screw pitch, z is the stem thread heads). <br> The stem diameter: multi-turn class rising stem valve, if the electric device allows a maximum diameter of the stem could not be passed with the valve stem will not .be able to build a electric valve. Therefore, the electric appliance hollow output shaft bore diameter must be greater than that of the valve stem diameter. On the part of the rotary valve and multi-turn valve of dark pole valve, regardless of the diameter .of the stem through the issues, but also in matching should take full account of the stem diameter and the dimensions of the keyway, make the Assembly works. <br> Output rotating speed: valve open and close speed if the fast, easy to produce .the phenomena of water hammer. Therefore, you should use under different conditions, choose the appropriate speed of opening and closing. Valve electric device have specific requirements that must be able to limit the torque or axial force. Usually valve electric device used to limit the .torque of the axle. When the electric device specification determines, in its control torque also determines. Generally predetermined time running, the motor will not be overloaded. But if the following conditions may cause Overload: one is the power supply voltage is low, not .the required torque, the motor stop rotation; the second is incorrectly set torque limiting bodies, making it larger than the stop of torque, Due to continuous large torque, the motor stop rotation; third, intermittent use, generate heat savings of more than a .motor of the raised temperature allowed; fourth, for some reason torque limit body circuit failure, making the torsion is too large; fifth, the ambient temperature is too high, the relative decline in the motor heat capacity. <br> <br> In .the past on motor protection would be to use fuses, overcurrent relays, thermal relays, thermostats, etc, but these disadvantages. The electric device this variable load equipment, absolutely reliable protection is not. Therefore, you must take a variety of combinations that can .be summarized in two ways: first, on motor input current judgment changes; the second is on the motor itself fever situation. This two ways, whether it should take into account the motor heat capacity given time allowance. <br> Typically, basic overload .protection: continuous operation of the motor or move operation overload protection, using the thermostat; protection for motor stalling, thermal relay; the short circuit fault, uses the fuse or overcurrent relays. <br> <br> <br>.