Powder cutting valve(HY-industry technical centre)

This valve is China’s CHUANWU, INSTRUMENT, CHONGQING CO., LTD. is a slide-cut valve for the pulverized coal cutting occasion produced by Hebi Coal and Electricity. This type of valve has been successfully used on the Shell furnace and has achieved a maintenance-free performance for 27 months of continuous operation. Compared with the 9-month operating life of foreign ball valves, it is three times that of foreign ball valves. Moreover, foreign valves often appear to be stuck, and the core is washed away by high-speed pulverized coal particles, causing leakage and other unfavorable production situations. Maintenance takes a lot of time, manpower and material resources.

Valve parameters:

  • Nominal diameter: 12”

  • Nominal pressure: Class600

  • Connection flange: 12″ Class600

  • Fluid medium: CO2+ pulverized coal

  • Pre-valve pressure: 5.01MPa

  • Operating temperature: 100 ° C

  • Maximum pressure difference: 5.61MPa

  • Leakage level: above level VI

  • Control method: pneumatic cylinder

  • Body material: WCB

  • Valve plate material: 17-4PH+ spray welding WC

  • Operating frequency: 20min/time

This type of valve has the following advantages over the ball valve structure:

1. The inner trim material is made of integral 17-4PH+ spray-welded WC alloy material. WC alloys have a higher hardness than Stellite 6. At the same time, the sealing surface is subjected to grinding treatment, the roughness can reach the mirror level, and the flatness is controlled below 0.2 micron to achieve leakage above level VI. The materials are the best materials for domestic certification and are provided by Shanghai HY Industry Co., Ltd.

2. The flow direction of the medium is 90° with the valve action direction. When working, it forms a strong shear force and directly cuts the solid particulate matter at the valve core and the valve plate. It will not scratch the sealing surface. When the ball valve is small, the solid particles are easily scratched or crushed to seal the inner parts.

3. Concealed sealing surface design, when the valve is fully open, the sealing surface is completely hidden, and the sealing surface is not subject to friction and wear; at a small opening degree, the flow direction of the medium is perpendicular to the sealing surface, which does not affect the service life of the valve. . As shown in the simulation flow diagram below, when the ball valve is at a small opening degree, the pulverized coal particles flow at high speed along the surface of the sphere (sealing surface), and the pulverized coal particles directly act on the sealing surface, so that the sealing surface is severely washed and worn, although The ball core and the seat material are specially hardened, but they cannot withstand the scouring wear of the high-speed granular medium. The service life of the valve is directly determined in the severely illustrated part. When the sliding valve is small opening, the flow direction of the medium is 90° to the sealing surface, the medium passes directly, and friction and wear are not generated with the sealing. Even if there is some wear at the corner of the sealing, the valve adopts the surface sealing structure and the sealing surface. There is a certain width.

4. The direction of movement of the valve is perpendicular to the flow direction of the medium, and the valve stem is pressed and pulled. The stem is subjected to several times the force of the ball valve (the tensile stress of the material is several times the torsional stress).

5. The sealing surface can produce self-healing effect during use, automatically repair unbalanced wear, and the valve sealing performance is better.

As shown in the figure below, it is the sealing surface after 27 months of valve use:

As can be seen from the figure, after 27 months of operation, the sealing surface can be smooth and flat like a mirror, and can be clearly imaged. Compared with the reflection at the factory, the flatness of the sealing surface and the roughness are further improved, and the ideal mirror level flatness is truly achieved. This situation is also unexpected. The reason for the analysis is that the valve plate and the valve seat are in relative motion, and self-grinding is formed under the action of the nano-sized powder, which is the same principle as the mirror polishing. In the medium, nano-sized powders often enter the micron-scale gap, and the entry of nano-sized powder can not only fill the micron-level defects, but also make the sealing surface and the valve seat completely fit, which helps the sealing function. Under the relative movement of the valve plate and the valve seat, it can also act as a grinding sand, automatically repair the friction damage, make the valve plate and the valve seat fit more tightly, the more the valve is used, the higher the sealing level.

6. Add a cavity purge interface to prevent the cavity from accumulating pulverized coal.
a Opening the DN25 purging hole on the inlet side of the valve body medium, and purging the cavity with high pressure N2, effectively preventing the valve from being stuck due to the accumulation of pulverized coal in the cavity.
b Purge mode is automatically controlled. When the valve is closed, the purge valve is opened and the purge valve setting is delayed by 5S.
As shown below:

Valves of this type have successfully solved the problem of cutting and permanent sealing in the case of powders, gases or liquids containing solid particulate matter. It has a longer service life and sealing performance than the imported ball valve and is an effective substitute for such imported ball valves.

Through the production practice, valves of this type can also be used in steam cutting applications. It is used in high temperature, high pressure steam, and requires tight sealing, which can highlight the advantages of this valve structure. To achieve the VI leakage level, the ball valve must adopt a soft sealing structure, and the soft sealing material can only withstand temperatures below 230 °. Even if it is aerospace engineering PEEK material, it can only be used below the peak temperature of 300 ° C. long-term use. The metal seal structure used in the slide-off valve is not affected by the operating temperature. Under the action of the medium pressure, the sealing surface is firmly adhered to the valve seat. The greater the pressure, the better the sealing performance.

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We have more than twenty years experience in kind of High temperature alloy production.

Inconel 718, Monel 400,Stellite 6,Stellite 12,Incoloy 800ht,Incoloy 901,Nimonic 80A,Kovar,Invar 36,Inconel 625,Hastelloy C276, Incoloy 825 are mature productes of us.

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