Types of Multi-Stage Pressure Reducing Control Valves

 
In the modern industry, multi-stage pressure reducing control valves play a crucial role in controlling fluid pressure and flow rates. Different types of multi-stage pressure reducing control valves, such as cascade, multi-layer sleeve, and labyrinth types, each have their unique designs and application advantages. Cascade control valves reduce pressure differences step by step through multiple series-connected throttling areas; multi-layer sleeve control valves handle high pressure differences with a stacked sleeve design; labyrinth control valves achieve strong pressure reduction and excellent anti-cavitation performance with complex labyrinth flow paths. This article will provide a detailed introduction to the structural features and application scenarios of these control valves, helping you make informed choices when facing different fluid control requirements.

Cascade Control Valves

 
Cascade control valves are a type of multi-stage pressure reducing control valve that utilizes a multi-stage throttling structure. The core design involves breaking down a single throttling area into multiple series-connected throttling areas. This design can convert a large pressure difference into several smaller pressure differences, with each pressure reduction controlled above the saturated vapor pressure, effectively preventing cavitation. These control valves are widely used in the control of liquid media, with the following main features:

1. Stepwise Pressure Reduction

 
Each throttling port operates with a delay behind the previous one, reducing the high pressure acting on the valve port step by step during the opening and closing process. This distributes the pressure on the first-stage throttling port, thereby reducing the pressure burden on the valve.

2. Low Flow Resistance

 
Due to its design characteristics, cascade control valves can handle applications with lower fluid cleanliness, even handling solid-liquid two-phase flows. The low flow resistance is conducive to improving the overall efficiency of the system.

3. Anti-Erosion and Cavitation Resistance

 
The cascade valve core is usually hardened with tungsten carbide spray coating, providing good resistance to erosion and cavitation. It is suitable for handling fluid media that can easily cause cavitation.

4. Limitation on Pressure Reduction Stages

 
The general number of pressure reduction stages for cascade control valves is three to four, suitable for occasions with lower pressure differences. In applications with high pressure differences, other types of control valves may be needed to meet the requirements.

Multi-Layer Sleeve Control Valves

 
The design feature of multi-layer sleeve control valves lies in the valve core part, which is composed of multiple sleeves with small holes. A certain gap is left between each layer of sleeves, allowing the fluid to be buffered when flowing through the sleeves, controlling the fluid velocity. The main features multi-layer sleeve control valves include the following aspects.

1. Strong Pressure Reduction Capability

 
Multi-layer sleeve control valves can be designed with a larger number of pressure reduction stages, compared to cascade control valves, they have a stronger pressure reduction capability and can handle high pressure difference applications.

2. Flow Assurance

 
This structure not only meets the requirements for high pressure drop but also ensures a large flow rate during operation, suitable for applications that require high flow and high pressure drop.

3. Anti-Cavitation Performance

 
In the application of liquid media, the fluid flows from the outermost sleeve to the innermost, reducing pressure step by step, reducing the occurrence of cavitation. The fluid finally sprays from the small holes on the inner sleeve to the central valve cavity area, causing bubbles to burst in the center of the sleeve, protecting the valve metal surface.

4. Noise and Vibration Resistance

 
When used in gas media, the gas expands step by step as it passes through the sleeves, reducing noise and vibration. The hole diameter and gap of the sleeves increase step by step, effectively reducing the impact of noise and vibration on the system.

Labyrinth Control Valves

 
The core design of labyrinth control valves is composed of multiple metal discs stacked with labyrinth grooves. The fluid undergoes multiple collisions and turns in the labyrinth flow path, gradually reducing pressure and controlling flow velocity. Labyrinth Control Valves exhibit major features as follows.

1. Excellent Pressure Reduction Capability

 
The number of turns in the labyrinth flow path determines the number of pressure reduction stages, generally reaching several to tens of stages, with some foreign products reaching up to 40MPa. This makes the labyrinth control valve have the strongest pressure reduction capability among all multi-stage pressure reducing control valves.

2. Anti-Cavitation and Noise Reduction

 
The labyrinth structure can effectively control the flow velocity of the fluid, preventing cavitation, noise, and vibration. The multi-stage turning labyrinth flow path design effectively alleviates these issues, ensuring smooth fluid flow.

3. Flow Characteristic Adjustment

 
Different forms of labyrinth disc combinations can achieve different flow characteristic adjustment curves to meet various process requirements.

4. Manufacturing Precision and Maintenance

 
Labyrinth discs require high precision manufacturing, usually using Stellite alloy cladding, and have a long service life. Although the manufacturing cost is higher, installation and maintenance are relatively simple, and the discs are easy to replace.

5. Cleanliness Requirements

 
The labyrinth flow path has higher cleanliness requirements for the fluid medium. If the fluid medium is not clean enough, it can easily cause the labyrinth flow path to be blocked, affecting the normal operation of the valve.
 
Choosing the right multi-stage pressure reducing control valve is crucial for enhancing the efficiency and reliability of industrial systems. Whether it is a cascade control valve, a multi-layer sleeve control valve, or a labyrinth control valve, each type has its unique advantages and best application scenarios. Understanding the characteristics of these valves can help you make the most suitable decisions in complex fluid control tasks, ensuring stable system operation and optimizing performance. It is hoped that this article will provide valuable reference for you when choosing the appropriate control valve.