Development Trends of Screw Insert Valve Technology

The development trend of threaded plug-in valves largely represents the development trend of hydraulic   valves, but it also   has its own characteristics.

1. Continuous increase in pressure
One of the biggest advantages of hydraulic technology is its high energy to capacity ratio, with the most important being high pressure. The working pressure of 2.5-6.3MPa in the last century has risen to 35-42MPa and even 48MPa today. However, in most application fields, it is still between 21-35MPa. The working pressure of pumps today has reached 42MPa, with a peak pressure of 48MPa, which requires the valve pressure to be above 42-48MPa. Both threaded and two-way plug-in valves are the most capable of   withstanding this pressure. And it is also possible to withstand higher pressure. From the perspective of materials and applications, 35-42MPa is currently moving towards economic rationality.

2. Development of increasing and decreasing valve diameter
An increase in valve diameter means a continuous increase in valve flow. The maximum diameter of the threaded plug-in valve is M48 × 2, and the flow rate of the throttle valve can reach 1600l/min; The flow rate of the logic valve reaches 800l/min; Check valve flow rate of 640l/min; Balance valve, flow valve, etc. 200-480l/min. This diameter is currently the largest among all threaded plug-in valves. The other direction is that the   valve can be reduced in a smaller direction for small flow ranges, such as less than 5l/min, which is already difficult in other valve types.
There are generally three measures for the development of threaded plug valves towards high flow rates: first, increase the diameter of the hole, but it is limited by the electromagnetic attraction of the electromagnet, so the development of the electromagnet is also necessary to strengthen the threaded plug valve; The second is to adopt a structure with a pilot valve and a logic main valve, and the flow amplification relies on the logic valve of the main valve; The third option is to use a higher working pressure difference, but this is the last resort.

3. Increase in variety of specialized valves with comprehensive functions
One of the biggest advantages of threaded plug-in valves over other types of valves is   that they   are   easy to develop and have a short cycle. The development in this area has evolved with the requirements of hydraulic applications. If the designers in the host industry are not only familiar with the process requirements of the host, but also have a better understanding of hydraulic threaded plug-in valves.

4. Improve the control accuracy of the control valve
At present, the best control accuracy of proportional control, balance valve, diversion valve, etc. for threaded plug-in valves is not as good as that of plate valves. From the thread insertion proportional   valves produced by most thread insertion valve manufacturers, the hysteresis loop is between 3-10%, the frequency response (-3dB) is below 10-25Hz, and the linearity is poor, which is one order of magnitude lower than that of plate valves. This is because currently, the main market for threaded plug-in valves   is still engineering machinery, and their load control accuracy is not high, which can meet   basic   requirements.However,threaded plug-in valves need to enter the field of industrial hydraulic   control,and   this control accuracy cannot meet the requirements, so there is still a lot of room   for   development.

5. Propose more material research requirements and enter the field of hydraulic engineering
The material selectivity of threaded plug-in valves is closely related to product performance and   lifespan, unlike plate valves that have already been standardized. Further research is needed. Develop materials or processes such as stainless steel, non-ferrous metals, and surface treatment to bring threaded plug-in valves into the field of hydraulic engineering. Due to the freedom of the valve body, threaded plug-in valves have a greater range of applications in terms of material, making them a good choice for future use in hydraulic and other applications.

6. New technologies such as bus technology entering electromagnetic control valves
The era of bus technology has come. At present, multinational enterprises have developed bus communication control systems that can be used for all hydraulic components, making the hydraulic control system more advanced and reliable in terms of electronic control. This is particularly important in engineering technology, as it is one of the directions for the development of construction machinery. At present, there is a significant gap in awareness among Chinese enterprises in this area.

7. Development of Digital Control Technology
At present, most digital valves adopt a threaded insertion structure because digital valves are mainly used as pilot valves with smaller diameters, making them more suitable for threaded insertion structures. It is also one of the directions in the future to seek new control methods that are easier to combine with computer technology and more reliable and cost-effective.

8. Challenges of threaded plug-in valves to production management technology
The parts of threaded plug-in valves have many small specifications and thousands of varieties,   and the   overall value of each individual is limited. Therefore, there are different production management methods and new requirements compared to plate valves. Especially for the existing foreign professional factories, the maximum annual output of a factory is 6 million pieces, which is equivalent to the production quantity of hydraulic components in China in 1998.