Manual Lining Rubber Wafer Desulfurization Butterfly Valve D71J/D371J

D71J/D371J manual rubber lined wafer desulfurization butterfly valve for limestone slurry and gypsum slurry desulfurization is a special butterfly valve for power plant flue gas desulfurization. The main structure consists of valve body, valve disc, valve seat, valve stem, and transmission operating mechanism. The valve seat adopts a detachable structure, and corresponding materials that are resistant to high temperature, low temperature, corrosion, light, and aging can be selected according to the physical and chemical characteristics of different media. Traditional butterfly valves often require pins or screws to fix the valve plate and valve stem, while desulfurization butterfly valves are usually made of special stainless steel or nickel based corrosion-resistant alloys. In order to avoid point corrosion and crevice corrosion caused by ordinary material pins or screws, traditional pins or screws cannot be used to connect the valve plate and valve stem. Therefore, desulfurization butterfly valves often adopt a non pin structure design. The inner and outer surfaces of the ductile iron shell of the valve can be coated with high-temperature electrostatic spraying epoxy resin powder, which has high corrosion resistance and extremely high bonding strength with the ductile iron matrix. The coating degree is 0.2-0.5mm. The desulfurization and denitrification butterfly valve is specially designed for power plant desulfurization and denitrification projects, fully considering the corrosion and wear of desulfurization slurry on the valve, ensuring that the valve plate lining is the only component that can come into contact with the slurry, while other components are not corroded by limestone (or lime paste) slurry. Therefore, the valve body and stem do not require expensive alloy materials (2205, 2507, 1.4529), greatly saving costs. The unique valve seat design of the desulfurization butterfly valve completely separates the valve body from the fluid medium. Compared with other similar valves, it has a better way to secure the valve seat, quick on-site replacement of the valve seat, zero leakage of the valve, and low friction. The butterfly valve plate is made of high-performance alloy materials (2205, 2507, 1.4529), which effectively resist the corrosion and wear of the slurry. Desulfurization dedicated butterfly valves can be widely used for regulating and intercepting flow in fluid pipelines such as water and electricity, sewage, construction, air conditioning, petroleum, chemical industry, food, medicine, light textile, paper making, water supply and drainage, etc. They can be modified by material to be suitable for different media such as water, gas, oil, etc., with a suitable temperature of -20 to 80 ℃. By replacing the valve plate sealing ring, O-ring, butterfly plate, shaft and other materials, it can be suitable for various media and different temperatures. The valve automatic control equipment is equipped with high-quality electric actuators or double acting pneumatic actuators, which can achieve automatic and manual dual opening and closing functions.
Product features:

1. Flexible selection of operating mechanism for butterfly valves;
2. The butterfly valve has a beautiful appearance and good corrosion resistance;
3. Reasonable design, compact structure, simple installation and disassembly, and easy maintenance;
4. The flow characteristics of the valve plate sealing surface are linear, with a small flow resistance coefficient, resulting in a small valve flow resistance;
5. The rubber sealing surfaces on both ends of the valve protrude from the ductile iron flange surface, and the valve does not require additional rubber sealing gaskets during pipeline installation;
6. Adopting a medium linear structure with no eccentricity design, it has a significant feature of low operating torque and significant economic efficiency when configuring electric devices;
7. Adopting a rubber lined structure, the butterfly plate’s circumferential sealing surface is precision machined to a high smoothness, resulting in extremely low friction coefficient for the rubber valve seat and a longer service life of the valve;
8. The uniquely designed molded rubber valve seat has excellent balance and support, effectively avoiding damage to the rubber caused by uneven force. When the valve is in the fully closed position, the rubber is in the best compression state to maintain zero leakage.

Main component materials:
Valve body: gray cast iron, ductile iron, carbon steel
Butterfly plates: carbon steel coated with rubber, carbon steel coated with fluoroplastics, stainless steel, duplex stainless steel plates 1.4529, 2507, C276
Valve seat: natural rubber (NBR), ethylene propylene diene monomer (EPDM)
Valve stem: stainless steel, 2Cr13, 304

Product external and structural size:

Applicable situation for butterfly valves
Butterfly valves are suitable for flow regulation. Due to the significant pressure loss of butterfly valves in pipelines, which is about three times that of gate valves, when selecting a butterfly valve, the impact of pressure loss on the pipeline system should be fully considered, and the robustness of the butterfly plate to withstand the pressure of the pipeline medium when closed should also be considered. In addition, it is necessary to consider the limitations of the working temperature that the elastic valve seat material can withstand at high temperatures.
The structural length and overall height of butterfly valves are small, with fast opening and closing speeds, and good fluid control characteristics. The structural principle of butterfly valves is most suitable for making large-diameter valves. When using butterfly valves for flow control, the most important thing is to choose the correct size and type of butterfly valve so that it can work properly and effectively.
Usually, in throttling, regulating control, and mud media, short structural length and fast opening and closing speed (1/4 turn) are required. Low pressure cutoff (small pressure difference), it is recommended to use butterfly valves.
Butterfly valves can be used in channels with dual adjustment, contraction, low noise, cavitation and gasification phenomena, small leakage into the atmosphere, and corrosive media.
When using butterfly valves under special operating conditions such as throttling adjustment, strict sealing requirements, severe wear, low temperature (deep cold) etc., special triple eccentric or double eccentric butterfly valves with specially designed metal sealing belt adjustment devices need to be used.
The mid line butterfly valve is suitable for fresh water, sewage, seawater, saline water, steam, natural gas, food, medicine, oil, various acid tanks, and other pipelines that require complete sealing, zero gas leakage during gas testing, high service life requirements, and operating temperatures between -10~150 ℃.
Soft sealed eccentric butterfly valves are suitable for bi-directional opening and closing and adjustment of ventilation and dust removal pipelines, and are widely used in gas pipelines and waterways in metallurgical, light industry, power, petrochemical systems, etc.
Metal to metal wire sealed double eccentric butterfly valves are suitable for urban heating, steam supply, water supply, gas, oil, acid-base and other pipelines as regulating and shut-off devices.
Metal to metal face sealed triple eccentric butterfly valves are not only used as program control valves for large pressure swing adsorption (PSA) gas separation devices, but also widely used in fields such as petroleum, petrochemical, chemical, metallurgical, and electric power. They are good substitutes for gate valves, globe valves, and so on.

The selection principles of butterfly valves

1. Due to the relatively large pressure loss of butterfly valves compared to gate valves and ball valves, they are suitable for pipeline systems with less stringent pressure loss requirements.
2. Since butterfly valves can be used for flow regulation, they are suitable for use in pipelines that require flow control.
3. Due to the limitations of the structure and sealing materials of butterfly valves, they are not suitable for high temperature and high pressure pipeline systems. The general working temperature is below 300 ℃, and the nominal pressure is below PN40.
4. Due to the short length of the butterfly valve structure and its ability to be made into a large diameter, it is advisable to choose a butterfly valve in situations where the structural length is required to be short or for large diameter valves (such as DN1000 or above).
5. Due to the fact that butterfly valves can be opened or closed by only rotating, it is advisable to choose butterfly valves in areas with fast opening and closing requirements.

Installation precautions:

1. Before installation, the specifications, pressure, temperature, and corrosion resistance of the butterfly valve should be checked to ensure that they meet the requirements for use. Each component should be checked for damage or looseness.
2. This butterfly valve can be installed on pipelines at any angle and should be closed for installation; When welding pipeline flanges, the valve sealing port should be blocked with a plate to prevent particles and debris from damaging the sealing surface. After welding, remove the valve, clean the valve sealing surface and pipeline cavity, and then install and fix the valve.
3. Please pay attention to the pressure direction when installing when the valve is closed.
4. Before installation, the sealing surfaces (sealing surfaces at both ends, butterfly plate sealing surfaces, and valve seat sealing surfaces) should be thoroughly wiped clean to remove dust and dirt.
5. Before installation, the butterfly valve should be air tested, with flexible opening and closing, and the opening and closing positions should match the indicated positions of the pointer.
6. Manually operate clockwise to close and counterclockwise to open. Do not apply force to open or close the valve after the pointer indicates it is in place.
7. When conducting pressure tests on valves, it is not allowed to use a single flange for installation and pressure testing. Double flange installation and pressure testing must be used. The test pressure should comply with the provisions of GB/T13927-92 standard.
8. When tightening bolts, they should be tightened symmetrically and alternately, and individual tightening in sequence is not allowed.
9. The limit screw has been adjusted before leaving the factory and should not be easily adjusted. If the drive device is configured as electric or pneumatic, please refer to the accompanying drive device manual.
10. The opening and closing stroke of the control mechanism has been adjusted when the electric butterfly valve leaves the factory. To prevent incorrect direction when the power is turned on, the user should manually turn it on to the half open position before the first power connection, then press the jog switch, and check that the direction of the indicator panel is consistent with the direction of the valve opening.

If the valve is found to have abnormal opening and closing, the cause should be identified for repair and elimination to prevent damage to the valve caused by using force to open and close the valve.