High Pressure Labyrinth Control Valve

OMAT High Pressure Labyrinth Control ValveOverview

OMAT high-pressure labyrinth control valve adopts a labyrinth cage combined with a balanced plug design. The labyrinth sleeve consists of multiple coaxial cylindrical discs, each featuring intricate labyrinthine paths. Depending on the medium's process parameters, the valve cage is designed with varying labyrinth path specifications and stacking layers. The cage divides the total flow path into numerous small,迂回甚至阶梯状分布的 throttling channels, forcing the fluid to continuously change direction and flow area, gradually reducing the fluid's pressure to prevent flashing and cavitation, thereby extending the service life of the valve trim. The balanced sleeve plug ensures extremely low leakage through tight配合 with the valve seat. This type of valve trim is suitable for various conditions prone to阻塞流动 causing cavitation.

For ordinary single-stage pressure-reducing valves, when the medium enters with pressure p1 and velocity v1, it reaches the plug section where throttling by the plug and seat causes necking, rapidly increasing velocity to v2 and decreasing pressure to p2, often below the medium's saturation vapor pressure Pv. Under these conditions, the medium vaporizes, forming bubbles. After passing through the necking section formed by the plug and seat, changes in the channel alter the operating conditions, pressure increases, kinetic energy converts to potential energy, pressure recovers to P3, and velocity recovers to v3. When pressure exceeds the medium's saturation vapor pressure Pv, the previously formed bubbles collapse, generating intense local pressure. The enormous energy from bubble collapse can severely damage throttling components like the plug and seat instantly, causing所谓的 cavitation. Cavitation inevitably leads to valve damage, leakage, severe noise, and vibration of valve internals, affecting the entire system's safety and efficiency.

OMAT High Pressure Labyrinth Control ValveFeatures

Since cavitation can generate surface impact pressures as high as thousands of atmospheres on throttling components, simply increasing the surface hardness of the plug and seat cannot fundamentally solve the cavitation problem. The anti-cavitation design of the labyrinth control valve utilizes the multi-stage pressure reduction principle of the labyrinth core package, forcing the medium through a series of right-angle bends to fully control velocity and achieve step-by-step pressure reduction. Regardless of the pressure drop size, the resistance of these bends limits the medium's exit velocity from the core package. Through multi-stage pressure reduction, the medium's pressure is always maintained above its saturation vapor pressure pv, avoiding cavitation and eliminating unsafe factors. The labyrinth core package is formed by bonding multiple labyrinth discs under special conditions (using adhesive). Each labyrinth disc is processed with specialized forming methods to create numerous channels, each allowing a certain amount of medium to pass, with a series of right-angle bends providing flow resistance. Based on precise calculations according to user requirements, different numbers of bend stages are selected to ensure the medium's velocity through the labyrinth core package remains within a certain range. Referring to international成熟经验, when velocity is less than or接近 30m/s, the erosive impact on throttling components is minimized. Since the flow rate and number of bends per labyrinth disc can be varied, and the disc thickness can be designed very thin (e.g., 2.5mm), the valve can be customized to meet specific user requirements for precise flow control. Depending on the valve's application and user needs, the control valve's flow characteristic curve can be designed as linear, equal percentage, modified equal percentage, or other special curve forms. As the working medium in power plant valves is essentially fluid (mainly water), labyrinth control valves generally adopt a flow-to-close structure. In this structure, the medium entering the valve body first passes through the core package, then the plug, and finally exits through the valve seat. The flow direction is indicated by a标记 on the valve body.

OMAT High Pressure Labyrinth Control ValveDetailed Parameters

Diameter DN15～300mm

Pressure PN1.0～PN42mpa

Applicable Temperature -30～+425℃

Applicable Medium Water, oil, gas, etc.

Connection Method Flange or welded

Valve Body Material WCB, 304, 316

Stem Material 304, 316

Sealing Material PTFE packing, 304, 316

Flow Direction Unidirectional

Purpose Regulation

Actuation Method Electric

Type Straight-through