Description
overview
The Extension Stem Butterfly Valve Dn600 150lb that uses a disc-type opening and closing member to reciprocate about 90° to open, close and adjust the fluid channel.
The butterfly valve is not only simple in structure, small in size, light in weight, low in material consumption, and small in installation size, but also has a small driving torque, is easy and quick to operate, and can also have good flow regulation function and closing and sealing characteristics at the same time. It is one of the fastest-growing valve varieties in the past decade. Especially in industrially developed countries such as the United States, Japan, Germany, France, and Italy, butterfly valves are widely used, and their varieties and quantities are still expanding, and they are developing in the direction of high temperature, high pressure, large diameter, high sealing, long life, excellent adjustment characteristics and one valve with multiple functions. Its reliability and other performance indicators have reached a high level, and it has partially replaced stop valves, gate valves and ball valves. With the advancement of butterfly valve technology, in the foreseeable short term, especially in the field of medium and low pressure use of large and medium-sized ports, butterfly valves will become the dominant valve form.
The technical requirements for the extended stem of the extended stem butterfly valve mainly include the following aspects:
Material selection: The extended stem is usually made of stainless steel, chrome-molybdenum steel and other materials to ensure its strength and corrosion resistance. For example, the valve stem can be made of 2Cr13, 1Cr13 stainless steel or chrome-molybdenum steel.
Structural design: The extended stem butterfly valve adopts a three-eccentric sealing structure, the valve seat and the butterfly plate are almost wear-free, and it has a sealing function that becomes tighter as it is closed. This design enables the valve to maintain good sealing performance in both low and high temperature environments
Sealing performance: The sealing ring is made of stainless steel, which has the dual advantages of metal hard sealing and elastic sealing, and has good sealing performance regardless of low and high temperatures. The sealing surface is made of surfacing cobalt-based cemented carbide, which is wear-resistant and has a long service life
Applicable media and temperature range: The extended stem butterfly valve is suitable for media such as air, water, sewage, steam, gas, oil, etc., with a wide range of medium temperature, and is suitable for various industrial pipelines. For example, the medium temperature can reach 425℃
Installation and maintenance: During installation, the valve disc should be stopped in the closed position, and the open position should be determined according to the rotation angle of the butterfly plate. For butterfly valves with bypass valves, the bypass valve should be opened before opening. Installation should be carried out according to the manufacturer's installation instructions. Heavy butterfly valves should be installed on a solid foundation.
Reasonable design
The structure is compact, easy to assemble and disassemble, and convenient for maintenance.
Eccentric structure
Reduce the friction of the sealing ring and extend the service life of the valve
Flow characteristics
Flow characteristics tend to be linear, with good regulation performance
Completely sealed
Zero leakage. It can be used in ultra-high vacuum conditions
Change material
Replace the valve plate seal ring, butterfly plate, shaft and other materials to suit a variety of media and different temperatures.
Installation Steps
The installation of the extended stem butterfly valve on the pipeline mainly follows the standard butterfly valve installation steps, and it is necessary to pay attention to the specific installation requirements brought by the extended stem. The following are the detailed installation steps:
Preparation before installation:
Install the valve in time after unpacking, and do not loosen any fastening screws or nuts on the valve at will1.
Check whether the extended stem is intact and has no damage or deformation.
Confirm the installation position and direction. The butterfly valve can be installed on the pipeline at any angle, but for the convenience of maintenance, it is recommended not to install it upside down. At the same time, it is recommended to place the valve shaft horizontally to prevent the mud and sand in the medium from entering the bearing.
Flange connection (assuming flange connection):
Place the valve between the two pre-installed flanges, and pay attention to the alignment of the bolt holes.
Place a gasket between the flange and the valve (if necessary), and ensure that the gasket is in the correct position.
Gently insert the bolts and nuts into the flange hole and tighten them slightly to correct the flatness of the flange surface.
Fix the flange:
Fix the flange to the pipeline using spot welding.
Remove the valve and then completely weld the flange to the pipeline. Pay attention to protecting the elastic valve seat from damage during welding.
Install the valve:
After the weld has cooled, install the valve back on the flange to ensure that the valve has enough room to move in the flange.
Correct the valve position and tighten all bolts. Be careful not to overtighten to avoid damaging the valve or flange.
Inspection and commissioning:
Open the valve to ensure that the valve plate can open and close freely, and open the valve plate slightly.
Tighten all nuts crosswise and evenly.
Confirm again that the valve can open and close freely and that the butterfly plate does not touch the pipe.
Specific precautions (for extended stem butterfly valves):
During installation, ensure that the extension stem does not interfere with the pipe or other components.
The extension rod may increase the overall weight of the valve, so pay special attention to the support and stability of the valve during installation and fixing.
If the extension stem is long, it may need to be additionally fixed or supported during installation to prevent it from shaking or deforming during use.
