1. Basic definition
The wedge gate valve is a valve that uses a wedge-shaped gate to achieve sealing. Its sealing surface forms a specific angle (wedge shape) with the vertical center line, and the gate and the valve seat are forced to form a seal through the thrust of the valve stem. It is widely used in petrochemical, power system and other scenarios, especially suitable for the cut-off control of high-pressure and high-temperature media (such as steam and oil products).
2. Core structure and classification
Sealing surface design
The sealing surface is wedge-shaped. When closed, the thrust of the valve stem is decomposed into positive pressure on the valve seat to enhance the sealing effect.
Gate types are divided into three categories:
Rigid single gate: The overall wedge structure relies on machining accuracy to ensure sealing, with low cost but weak adaptability.
Elastic gate: An annular groove is opened in the middle of the gate to allow slight elastic deformation to compensate for machining errors or thermal expansion and contraction to avoid jamming.
Double gate: Two gates are hinged through the top center of the spherical surface, which can automatically adjust the fit of the sealing surface and have better sealing performance.
Drive mode
Main types include manual, electric (such as wedge-type electric gate valve), and pneumatic (such as the pneumatic with manual design in the patent).
3. Working principle
Seal formation mechanism
Low pressure conditions: The valve stem thrust presses the wedge gate against the valve seat to generate self-enhanced sealing force.
High pressure conditions: The medium pressure pushes the gate close to the outlet valve seat to enhance the sealing effect.
Switching characteristics
The gate quickly detaches from the valve seat at the moment of opening to reduce the wear of the sealing surface; forced sealing ensures reliability when closed.
4. Applicable scenarios
Harsh working conditions
High temperature and high pressure pipelines: such as oil and natural gas transportation (in accordance with API 600 standards), thermal power plant steam systems.
Medium type
Oil, water vapor, natural gas and other clean media, scenes with high sealing requirements.
5. Advantages and disadvantages analysis
Advantages
Forced sealing adapts to high and low pressure environments, and has strong low pressure leakage prevention capabilities.
The elastic gate design resists thermal deformation and avoids high temperature jamming.
Limitations
High processing accuracy is required, and wedge angle deviation can easily lead to opening and closing jams.
Not suitable for medium containing particles or viscous media (easy to block the wedge gap).
