Wear-resistant combined valve head

Abstract

The invention belongs to the technical field of a valve and particularly relates to a wear-resistant combined valve head. The wear-resistant combined valve head serves as a main part of an adjusting valve and is used cooperatively with a valve rod and a valve seat; and the wear-resistant combined valve head comprises a valve head assembly, a coating sleeve assembly and a valve head base. Through reasonable material selection and optimized cooperation of the valve head base, a compensating bushing and a hardening sleeve in the valve head assembly, the wear-resistant combined valve head can be guaranteed to work reliably within the operating temperature range, and overcomes the phenomenon that the existing combined structure is bound to increase the interference magnitude at room temperatureto guarantee interference connection at the operating temperature to cause that parts exceed the yield limit to be damaged. In a similar way, the phenomenon that the existing combined structure reduces the interference magnitude at high temperature to guarantee that the parts are not yielded at room temperature to cause that the grasping force among the parts is insufficient, even gap occurs andthe valve head is vibrated to fall off is overcome.

Description

technical field [0001] The invention belongs to the technical field of valves, in particular to a wear-resistant combined valve head. Background technique [0002] Regulating valves are often used in some extreme operating conditions, such as high temperature, high pressure difference, and working medium containing hard particles, which will cause wear, corrosion or erosion of the valve head, resulting in cracking and breaking of the valve head, thereby causing The adjustment ability of the valve is weakened or even lost. Integral valve heads made of cemented carbide materials in the early days, such as silicon carbide (SiC), tungsten carbide (WC), silicon nitride (Si3N4), aluminum oxide (corundum Al2O3) and titanium nitride (TiN), have great High hardness, often used in high temperature, high pressure, strong corrosion, strong erosion, strong flashing or mud, it has incomparable wear resistance of commonly used surface hardening valve heads. [0003] However, the overall ...

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Problems solved by technology

It is difficult to choose the interference between the cemented carbide valve head and the steel valve stem with a large difference in linear expansion coefficient. If the selection is unreasonable, the following problems will occur: to ensure that the valve head and the valve stem maintain a reliable interference at the operating temperature When working, the material interference will increase at room temperature and cause the steel valve stem to yield. If the steel valve stem has a reasonable interference at room temperature and does not yield, the valve head and the valve stem will be too tight at the operating temperature. Insufficient surplus or gaps are formed, and the connection will fail under the influence of vibration under long-term use

[0006] 2. Due to the high molding density of the cemented carbide material itself, the center of gravity of the cemented carbide valve head and the valve stem is shifted to the valve head after the connection, so that the deformation of the valve stem is too large, the position of the sealing surface changes, and the sealing is difficult to achieve

[0007] 3. In order to reliably connect the valve head and the valve stem, parts such as snap rings or clamping sleeves are used. These parts are wrapped outside the valve head, which increases the radial size of the valve head assembly. If other structures restrict the radial size of the valve body If it cannot be increased accordingly, the flow area of ​​fluid in the valve body will decrease accordingly, resulting in increased flow resistance and weakened flow capacity.

In addition, the increased radial size of the valve head will further shift the center of gravity of the item to the valve head, which will further increase the difficulty of sealing

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