So far, the hydraulic transmission and control technology has developed into the mature application technology. With advantages of high power density, flexible layout, steady transmission and continuously variable, the hydraulic transmission and control technology are widely applied in the industrial circle. As the control component of the hydraulic system, the development of hydraulic valve has two sides. On one hand, it restricts the development of fluid technologies. On the other hand, it plays a leading role in the development of hydraulic transmission and control technology.

Hydraulic valve has many types according to different applications. The hydraulic solenoid valve is a common type, and it is controlled by the solenoid.

History of hydraulic valve

Review the development of hydraulic valve, it has a long history. Learn the development law and summarize the development direction will be helpful to forecasts its developmental trend.

  1. The hydraulic valve is originally developed from the valve. The valve first appears in the hydraulic engineering and riparian work. At that time, the valve is mainly used to cut off the flow or change the flow direction. So the valve has no requirement of strict sealing and flows regulation, there is no a concept of pressure regulation.
  2. With the advent of the steam, for ensuring the safety of boiler, a device similar to safety valve appeared to achieve pressure-protection. At this point, the pressure regulation is introduced to the fluid technology.
  3. In the 1870s, the steam technology had achieved strategically progresses. The invention of steam engine leads the valve to the mechanical engineering field. The plug valve, relief valve, and check valve, even the butterfly valve were applied in the Watt’s steam engine. With incensement of fluid and pressure of the steam engine, existing types of the valve cannot meet the requirement, as a result, the slide valve appeared. Based on the function of direct control and fluid regulation, the slide valve is important for the hydraulic transmission technology.
  4. In the 19th century, the hydraulic and pneumatic technology developed into industrial application. The demand of the social industry since the industrial revolution stimulates the development of hydraulic and hydraulic elements. The traditional on-off valve is fully developed, producing pressure valve, fluid valve, and directional valve.
  5. In the 20th century, the development of manufacturing industry, metallurgy of steel and petroleum mining promote the hydraulic transmission and control technology to the top.
  • Harry Vickers invented the pipe series liquid control element marked by pilot control pressure valve in 1936. After that, the on-off hydraulic control valve came out, which provide the power source. For some special situation, these types of valve can’t meet the requirement of function, precision and action time.
  • In the 50s, linear control theory has great influence on hydraulic control technology. Due to the requirements of servo-control in the aerospace, hydraulic servo valve came out. The hydraulic servo valve is a combination of hydraulics and electronics, and it is suitable for the needs of automatic control.
  • In the late 60s, various civil engineerings have different needs of electro-hydraulic control technology. At this time, the hydraulic system is generally used in the simple electric installation, and they have a lower requirement for the response speed and control accuracy. The proportional control valve was published by this kind of need.
  • In the 70s, the hydraulic logic valve appeared, solved the problem of high-flow hydraulic application. the hydraulic logic valve achive motion requirement. Compared to common hydraulic valves, the hydraulic logic valve has advantages of lightweight, less area, and fast response speed. it is perfect for the high-flow hydraulic system. 
  • In the 80s, the largest improvement of this period is proportional cartridge technology. the proportional cartridge valve reduced the system, and greatly accommodate the technological preferences of high power engineering control. 
  • in the 90s, mechatronics became the future trend of engineering machinery development. the digital valve was created under such circumstances. The digital valve has a simple structure, great technology, lower cost and strong anti-pollution capacity. but the digital jas slow speed of development and narrow applications. In general, the digital valve is used in the pilot control and low flow control, Such as numerical electro-hydraulic servo valve and numerical proportional valve. 

6. In the 21st century, researchers made full use of the development of other disciplines to develop hydraulic technology, such as the simulation and design of computer application, computer integrated manufacturing, computer intelligent control, computer fuzzy control, to achieve the mechatronics and intelligentize of hydraulic technology. The development of hydraulic valve is closely related to the development of hydraulic technology.

Development trend of hydraulic valve

At present, the development trend of the hydraulic valve can be sum up to several aspects as below:

  1. Energy saving

It is necessary to develop efficient hydraulic valve like lower powered solenoid directional valve.

  1. Controllability

The wide application of computer, development of various sensors and control theory produce a chance for improving the hydraulic property and increasing controllability. To meet the need of microcomputer control system and digital control system, we can improve electro-hydraulic servo valve property and aboard its applications, develop high-performance electro-hydraulic proportional valve and digital control valve.

  1. Reliability

The development of hydraulic valve trends to high pressure and high speed, which lead to the high requirement of reliability and life. So there are some basic studies on the characteristics of the hydraulic valve. For example, study on the dynamic characteristic of fixed orifice and the variable orifice; a study on the transient flow force in the slide valve; calculation on the transient flow force of super speed electro-hydraulic servo valve;  study on the flow force in the converged flow cone valve; study on the cavitation of hydraulic valve.

  1. Intelligence

For achieving the telecontrol, the hydraulic widely adopt electric control, which means control the hydraulic valve by the electrical signal. Currently, there is a kind of intelligent combination valves, also called programmable electro-hydraulic control valve. The intelligent combination valve is an integration of electronic technique, computer control technique and general hydraulic valve.

  1. Greenization

With increasing ecological and environmental concerns, and proposing the idea of sustainable development, the medium, materials, and technology of hydraulics should meet requirements of eco-environment protection. The hydraulic valve must have to meet the concept of green design, green technology, and green product.