1、 Large opening work

Let the regulating valve work at a high opening from the beginning, such as 90%. In this way, damage such as turbidity and erosion occurs on the head of the valve core. As the valve core is damaged and the flow rate increases, the corresponding valve is closed a little more. This continues to damage and gradually closes, allowing the entire valve core to be fully utilized until the root and sealing surface of the valve core are damaged and unusable.

At the same time, the large opening has a larger throttling gap and reduces erosion, which increases the lifespan of the valve by more than 1-5 times compared to working at intermediate and small openings from the beginning. If a certain chemical plant adopts this method, the service life of the valve has been doubled.

2、 Reduce the valve resistance ratio (or pressure drop ratio) S

Reducing S means increasing the losses of the system except for the regulating valve, reducing the pressure drop distributed to the valve. In order to ensure that the flow passes through the regulating valve, the opening of the regulating valve must be increased. At the same time, the pressure drop on the valve decreases, reducing cavitation and erosion.

The specific methods include: setting an orifice plate behind the valve to throttle and consume pressure drop; Close the manual valves connected in series on the pipeline until the regulating valve achieves the desired working opening. This method is very simple, convenient, and effective for workers who choose a large valve with a small opening at the beginning.

3、 Reduce the aperture and increase the working opening

The specific methods for increasing the working opening by reducing the diameter of the valve include:

① Replace a valve with a smaller caliber, such as DN32 with DN25;

② The valve body remains unchanged, and the valve core and seat with a smaller diameter will be replaced. During a major overhaul of a chemical plant, replacing the throttling component dg10 with dg8 doubled its lifespan.

4、 Transfer the damaged location

Move the severely damaged areas from critical positions to secondary positions to protect the sealing and throttling surfaces of the valve core and seat. It can improve the service life of the valve.

5、 Change the flow direction

The flow opening type flows towards the direction of the valve core opening, and cavitation and erosion mainly act on the sealing surface, causing the root of the valve core and the sealing surface of the valve core seat to be quickly damaged;

The flow closed type flows in the direction of closure, and cavitation and erosion act below the sealing surface of the valve seat after throttling, protecting the sealing surface and the root of the valve core, and extending the service life.

Attention: After changing the flow opening to flow closing, there may also be a jumping phenomenon (when the regulating valve is open), and there is a vortex effect during the regulation process, which makes the control system unable to adjust smoothly. The use of this method must be approached with caution and comprehensive consideration.

6、 Use special materials instead

To resist cavitation (damage to honeycomb shaped small dots) and erosion (streamlined small grooves), special materials that are resistant to cavitation and erosion can be used to manufacture throttling components.

This special material includes 6YC-1, A4 steel, Steller, hard alloy, etc. To resist corrosion, materials that are more corrosion-resistant and have certain mechanical and physical properties can be used instead.

This type of material is divided into two categories: non-metallic materials (such as rubber, PTFE, ceramics, etc.) and metallic materials (such as Monel, Hastelloy, etc.).

7、 Correct selection of valve structure

By changing the valve structure or selecting valves with longer lifespan, the goal of improving lifespan can be achieved, such as using labyrinth valves, multi-stage valves, anti cavitation valves, corrosion-resistant valves, etc.

The advantages of regulating valves during use are:

1. Agile movements, able to complete various adjustment commands in a timely manner;

2. When used in conjunction with a large cylinder, it has a greater torque thrust force;

3. Stable performance and normal operation in harsh working environments;

4. High security performance.

The normal operation and agility of regulating valves have a direct impact on production quality and efficiency. Therefore, it is particularly important to analyze the factors affecting the failure of regulating valves during use and provide solutions.