Material and Technical requirements of valve Electric actuator for power station valve (1)

Material and Technical requirements of valve Electric actuator for power station valve (1)

First of all, in terms of valve selection, in the early days of the establishment of the Special Zone, the water supply pipe network was less than 10 km, and most of the pipe network used gate valves. Due to the simple pipe network and good tightness of gate valves, the role of valves in the pipe network was not very important. Soft seal butterfly valve. The sealing surface is usually made of butadiene rubber and epDM rubber, etc. Reclaimed rubber is strictly prohibited. Sealing material must meet the requirements of health indicators, and to indicate the anti-aging test and wear resistance test data;
First of all, in terms of valve selection, in the early days of the establishment of the Special Zone, the water supply pipe network was less than 10 km, and most of the pipe network used gate valves. Due to the simple pipe network and good tightness of gate valves, the role of valves in the pipe network was not very important. And into the early 1990s, the use of butterfly valve nationwide vigorously, at that time, China’s butterfly valve production just started, in the body casting strength is not high, valve plate apron sealing performance is poor, the quality of butterfly valve problems are more and more obvious exposed. The valves used in the pipe network are classified by caliber: gate valve is used when DN≤400mm, butterfly valve is used when DN400mm. The main basis of classification is that 90% of the maintenance management work in the pipe network occurs in the small-caliber pipe network below DN400mm, so it requires good tightness of the opening and closing of the valves in the pipe network. And because the caliber is small, the labor intensity of valve opening and closing is not large. However, the frequency of pipe burst in DN400mm pipe network is much lower than that in small-caliber pipe network, and the labor intensity of opening and closing after using butterfly valve is decreased.
The current problem in the valve procurement link our company also put forward the corresponding technical requirements:
1, valve material requirements
The valve body and valve plate should be made of ductile iron.
(2) stem material. Gate valves shall be stainless steel stem (2Cr13), butterfly valves shall be stainless steel stem inserts;
Nut material. It should be made of cast aluminum brass or cast aluminum bronze, whose hardness and strength are greater than the valve stem;
The material of sealing surface
A, common wedge gate valve. The copper ring shall be cast aluminum brass or cast aluminum bronze;
B, soft seal butterfly valve. The sealing surface is usually made of butadiene rubber and epDM rubber, etc. Reclaimed rubber is strictly prohibited. Sealing material must meet the requirements of health indicators, and to indicate the anti-aging test and wear resistance test data;
Valve shaft packing. V rubber ring or carbon fiber impregnated polytetrafluoroethylene packing, should ensure good sealing performance, no leakage; When opening and closing frequently, the packing is not active, not aging, and the sealing effect should be maintained for a long time, which should be guaranteed for at least ten years or longer.
2. Technical requirements of variable speed transmission box
The body material should be consistent with the body material;
(2) The transmission box is required to be sealed and can withstand not less than 3 meters of water depth without leakage;
(3) There is no sundries in the box, and grease should be used to protect the closest part of the gear.
3, soft seal butterfly valve structure and technical requirements:
(1) The valve should be closed clockwise rotation;
② The valve body should be provided with a butterfly plate limit block, its strength must be greater than the opening torque of the valve;
The sealing ring should be fixed on the valve body, and the sealing ring pressing plate should be dovetail pressing plate with reliable anti-loosening measures;
(4) the valve opening and closing operating end should be square tenon, and the size of standardization, and face the ground;
The scale line of the valve opening and closing degree should be cast on the gearbox cover or the display plate shell after the conversion direction, uniform surface, and the scale line is brushed with fluorescent powder to show eye-catching.
4, contact water flow in the valve body part and valve plate should be anticorrosive measures, such as sand cleaning and rust spraying powder non-toxic epoxy resin.
5, requirements for valve signs
When the valve leaves the factory, the valve factory should give each valve a fixed number, its number and valve model, caliber, nominal pressure, valve number, manufacturer, production date and other valve label content should be fixed on the valve body.
Introduction of electric actuators for power station valves (1) This standard specifies all kinds of electric actuators for power station valves (hereinafter referred to as electric actuators), including terms, types, technical requirements, type selection, test methods, inspection rules, marks, packaging, transportation and storage technical requirements for power control. This standard is applicable to different types of electric actuators such as shut-off valves, regulating valves and baffles driven by motors. *** versions of undated references apply to this international Standard.
1, scope,
This standard specifies the electric actuators for all kinds of power station valves (hereinafter referred to as electric actuators), including the terms, types, technical requirements, type selection, test methods, inspection rules, marks, packaging, transportation, storage and other technical requirements for power control.
This standard is applicable to different types of electric actuators such as shut-off valves, regulating valves and baffles driven by motors.
2. Normative reference documents
The provisions of the following documents are incorporated into this international standard by reference. All subsequent amendments (excluding errata) or revisions to dated references do not apply to this international Standard. However, parties to an agreement under this International Standard are encouraged to investigate the availability of *** versions of these documents. *** versions of undated references apply to this international Standard.
GB 755 Rating and performance of rotary motors
GB/T 997 motor structure and installation type code
GB/T 3797 Electronic control equipment — Part 2: Electronic control equipment equipped with electronic components
GB 4208 Enclosure protection class (IP code)
GB/T 12222 Connection of multi-turn valve drive device
GB/T 12223 Connection of partial rotary valve drive device
GB/T 13306 signs
JB/T 8218 actuator terminology
JB/T10308.3 Field bus for measuring and controlling digital data communication industrial control systems
3. Terms and Definitions
The following terms and definitions apply to this International Standard; Other terms and definitions used in this international Standard refer to JB/T 8218
3.1 rated torque Normal Torque
Torque design given value.
3.2. Control the torque tripping torque
In the two directions of open and close, the torque control mechanism can control the torque range value, also known as cutting torque.
The control torque can be divided into large control torque and small control torque. Relatively large control torque is the torque control mechanism can control relatively large control torque is the torque control mechanism can control the minimum torque.
Locked torque
Torque output by the electric actuator when the rotor of a motor is blocked.
3. Set the torque setting torque
According to the requirements of users, the torque value is controlled by the electric actuator adjusted before delivery.
3. 5. Output speed
DL /T 641-2005
The design set value is the rotation speed of the output shaft of the electric actuator.
6. 6
Is the time required by the electric actuator to run from the “full off” position to the “full on” position or from the “0%” stroke to the “100%” stroke.
Intrinsic error
Under the specified reference conditions, the large difference between the actual stroke characteristic curve and the specified stroke characteristic curve is expressed as a percentage of rated stroke.
3. Hysteresis plus Dead band
The larger difference between two corresponding stroke values of the same input signal rising and falling within the rated stroke range, expressed as a percentage of the rated stroke.
3.9 dead Bend
A finite interval within which a change in the direction of the input signal does not cause any change in stroke, expressed as a percentage of the signal value range.
3.10. Power Control Component
An electrical device that converts and amplifies input electrical signals to control the starting, stopping and rotating directions of a motor.