Valves Processed by Diamond Special Spraying

Valves Processed by Diamond Special Spraying


Diamond super wear-resistant ball valves are used in harsh working conditions in polysilicon, coal chemical, petrochemical and other industries, such as high temperature, high pressure, high flow rate media, high frequency opening and closing and a large number of solid particles. The diamond coating with special spraying process has high hardness (greater than and equal to HRC80), and also has good self-lubricating, friction resistance, and erosion resistance. The service life of the valve is 2 to 3 times that of supersonic sprayed tungsten carbide valves.
 
With the rapid development of the economy, people have put forward new requirements and expectations for the rational use of energy. It is very important to develop and utilize a new generation of clean and efficient new energy. Coal gasification technology is one of the key technologies to achieve clean coal conversion. Chemical industry and energy systems based on coal gasification have become a hot spot for efficient, clean and economical utilization of coal resources worldwide. As the leader of the coal chemical industry, coal gasification equipment requires great investment. Most of the valves with high requirements for special purposes are imported, which are expensive and have long delivery cycles. The quality of the valves in such working conditions is directly related to safe production and operation of the gasification equipment.
 
Technical improvement
According to the special working conditions of coal gasification, a special surface treatment process called diamond high vacuum laser cladding process is introduced and developed. Its surface hardness is HRC78 or above, operating temperature 650℃ to 750℃, friction coefficient 0.03 to 0.05, making the service life of the wear-resistant ball valve on the coal gasification equipment 2 to 3 times that of the supersonic coated tungsten carbide metal seated ball valve. The spherical surface treated by the diamond process also has good friction resistance, erosion resistance and self-lubricating properties. Diamond super wear-resistant diamond ball valves are used in very harsh coal gasification conditions, such as high temperature and high pressure, high flow rate media, high frequency opening and closing and a large number of solid particles.
 
According to the special working conditions of coal gasification, the following improvements have been made to the design structure of traditional metal seated ball valves:
1. Solution to external leakages
Position the valve stem accurately to avoid uneven wear of the packing caused by its lateral displacement. The combined stuffing box consisting of leaf spring preloaded packing gland and elastically compensated double sealing rings provides excellent sealing performance for stems and avoid external leakage in extreme environments and working conditions.
 
2. Excellent sealing performance
Using a unique ball grinding process, the ball and grinding tools rotate in different directions to achieve absolute roundness and smoothness on the ball surface. The valve seat’s sealing surface adopts a wider spherical sealing structure, which can reduce possible scratches and minimize the damage rate of the valve seat. The valve’s sealing performance fully meets or exceeds the standard requirements, and the sealing grade reaches level VI (zero leakage).
 
3. The ball and valve seat meeting the requirements of self-shearing and self-cleaning
The sealing pair adopts a full O shaped sphere, double valve seats, and a leaf spring loading structure; the valve seat sealing surface is designed with a scraper structure, which can be removed when the valve is opened and closed.
 
4. Silicon powder bonded to the spherical surface
It has self-shearing and self-cleaning functions; the leaf spring adopts a double graphite sealing structure. When the valve is sealed, the leaf spring is also sealed. The medium will not enter the leaf spring deformation chamber, and the leaf spring will not be blocked and fail. It can be used for a long time. Meet loading requirements and improve durability of sealing performance.
 
5. Preventing the valve stem from blowing
The valve stem adopts an anti-blowout structure design, which ensures that the valve stem will not be removed by the medium even in extreme situations such as abnormal pressure increase in the valve cavity and failure of the packing pressure plate. The valve stem adopts a bottom-mounted structure design with an inverted seal. The sealing force of the inverted seal increases with the increase in the medium pressure, so reliable sealing of the valve stem can be ensured under various pressures.
 
Prevent the valve from swelling at high temperatures. Under high temperatures, the thermal expansion surface can easily cause the ball and valve seat to swell, causing the valve to fail to open. The metal seated ball valve adopts a leaf spring-loaded utility model patented sealing structure. In this case, the thermal expansion between components can be absorbed by the leaf spring or spring, so it can ensure that the valve will not be swollen at high temperatures and can be opened flexibly at high temperatures.
 
6. Perfectly optimized structural design
Fire protection: The sealing surface of the valve adopts a metal seated sealing structure; the filler adopts flexible graphite, and the gasket adopts a structure of stainless steel and flexible graphite. Therefore, reliable sealing can be ensured even in fire situations.
Anti-static effect: All parts of the valve are well connected, naturally forming an electrostatic channel. There is no need to design a separate electrostatic channel to protect the valve.
Double blocking effect: Diamond ball valves generally adopt a ball front seat sealing structure. The two valve seats of the ball valve can independently cut off the medium at the inlet and outlet ends to achieve double blocking effect.
Prevent misoperation: An opening and closing positioning piece with a lock hole at an angle of 90 is provided, which can be locked as needed to prevent misoperation.
 
Set up the installation platform: Diamond ball valves are all equipped with a bracket platform for installing the drive device. The worm gear device, pneumatic device or electric device can be easily installed through the driving bracket.
Surface treatment: Diamond coated tungsten carbide POD morphology
Wear rate: 6.00E-17 2.40E-15
Microhardness: (load 50g)
Equipment: MH-6 Microhardness Tester 2776HV 1472HV 6
 
Conclusion
The hardness of diamond coating is higher, about 2 times that of sprayed WC; the POD wear testing machine shows that the wear marks of sprayed WC are obviously deeper, while the diamond coating has almost no wear depth after 1800s of wear, and the wear resistance is good.