Description   

The High Pressure Drop Minimum Flow Control Valve is a precision control valve specifically designed for extreme operating conditions. Its core function is to achieve precise regulation of minimal flow rates under high differential pressure conditions. Through a multi-stage throttling element design within its flow path, it effectively controls medium velocity, suppresses cavitation, and reduces high-speed erosion, vibration, and noise. This ensures stable valve operation and prevents damage.

   Technical Advantages   

I. Current Market Analysis

Most high pressure drop minimum flow control valves currently on the market adopt labyrinth or multi-hole structures to distribute pressure differential, reduce medium velocity, suppress noise, and achieve anti-cavitation effects. While the labyrinth throttling structure offers excellent regulation performance, it has an inherent drawback: susceptibility to clogging. Even very fine impurities can block the labyrinth channels, leading to reduced valve regulation accuracy, delayed control response, and even system pressure fluctuations or abnormal equipment shutdown. The high pressure drop minimum flow control valves designed and manufactured by Global Valve Group feature an optimized labyrinth channel design that effectively resolves clogging issues, significantly enhances valve stability, and extends service life.

II. Design Optimizations

1. Novel Labyrinth Throttling Structure: The flow channel of the new labyrinth structure is designed bottom-up, with the internal diameter gradually increasing stage-by-stage according to the flow curve characteristics. If the valve plug becomes clogged by impurities in the medium, the valve can perform rapid full-opening and full-closing cycles to flush the plug's channels. This allows impurities to be carried through the larger channels at the top of the plug downstream, ensuring regulation accuracy and stability.
2.  Tapered Restriction Orifice Design: Tapered restriction orifices are installed at both the inlet and outlet of the valve flow path. The conical surface design effectively prevents the accumulation and clogging of medium impurities at the throttling holes. Working in conjunction with the labyrinth throttling components, they form a multi-stage throttling system, enabling precise control of the medium velocity.
3.  Composite Packing Structure: The packing set utilizes a composite structure. The incorporation of soft steel sheets enhances rigidity. Compared to traditional structures that rely solely on gland compression for sealing, this design distributes the compressive force more evenly to each packing unit without compromising the packing's plasticity and sealing performance.

III. Working Principle

When high-pressure fluid (liquid or gas) flows through the valve, it first passes through the tapered restriction orifice at the inlet, then proceeds through the labyrinth throttling components, and finally exits through the tapered restriction orifice at the outlet. Throughout this process, the high differential pressure energy is gradually dissipated and converted through multi-stage pressure reduction, effectively avoiding destructive cavitation and high-speed erosion at any single pressure drop point. Simultaneously, minimal changes in the valve plug opening precisely regulate the fluid flow through the throttling orifices, enabling stable and controllable minimal flow rates to meet precise process requirements.

   Parameters   

l Nominal pressure: PN16-PN760 (150LB-4500LB)

l Nominal diameter: DN20-DN150 (3/4”-6”)

l Regulatory range: 10:1-100:1

l Hull material: WCB, A105, WB36, 12Cr1MoV

l Working temperature: --29℃~570℃

l Working environment: water

l Method of connection: flange, welded

l Control mode: electric, pneumatic

   Applications   

As an integrated precision device for "equipment protection and flow control," the High Pressure Drop Minimum Flow Control Valve delivers core value through:
① Maintaining the minimum safe flow rate of critical equipment such as high-pressure pumps and compressors, preventing failures caused by cavitation, overheating, and deformation at the source.
② Enabling precise regulation of ultra-low process media flow via a multi-stage labyrinth throttling structure, ensuring system operational safety under extreme differential pressure conditions.

Typical Industry Applications:

Ø Petrochemical Industry:
Suitable for hydrocracking units and high-pressure water injection pump systems. It controls the minimum recirculation flow at the pump inlet to prevent centrifugal pump cavitation.

Ø Power Industry:
Applicable in minimum flow protection systems for feedwater pumps in thermal power units. The valve automatically opens to maintain the minimum required flow when unit load drops abruptly, preventing pump damage from overheating. It is compatible with boilers using feedwater pumps in units ranging from 100MW, 200MW, 500MW, to 1000MW.

Ø Metallurgy and Coal Chemical Industries:
Used in blast furnace gas compressors and feedstock gas compressor systems in coal-to-hydrogen plants. It ensures minimum flow control for compressors to prevent surge-induced impeller damage.