PARKER proportional valve D31FBE01CC1NF00 in stock

Brand

PARKER/Parker (USA)

PARKER Proportional Valve Advantages and Disadvantages:

PARKER proportional valve spool structure: The main valve of a servo valve generally has a spool structure similar to a directional valve. However, the valve spool is not driven by an electromagnet, but by the hydraulic pressure output from the pilot valve. This is similar to an electro-hydraulic directional valve, except that the pilot valve of an electro-hydraulic directional valve is an electromagnet, while the pilot valve of a servo valve is a nozzle-flange valve or jet valve with better dynamic characteristics.

In other words, the main valve of a servo valve is controlled by the output pressure of the pilot valve, and the pressure of the pilot valve comes from the inlet (p) of the servo valve. If the pressure at port p is insufficient, the pilot valve cannot output enough pressure to actuate the main valve spool.

As we know, with zero load, if the four-way spool valve is open, the pressure at port p = pressure at port t + pressure loss at the valve port (ignoring other pressure losses in the oil circuit). If the pressure loss at the valve port is very small, and the pressure at port t is zero, then the pressure at port p is insufficient to supply the pilot valve to actuate the main valve spool, and the entire servo valve will fail. Therefore, the valve port of the servo valve is made relatively small, so that even when the valve port is fully open, there must be a certain pressure loss to maintain the normal operation of the pilot valve.

PARKER proportional servo valves actually have many disadvantages: high energy consumption, prone to failure, poor contamination resistance, high price, etc. Their only advantage is that their dynamic performance is the highest among all hydraulic valves. Because of this single advantage, servo valves are necessary in many applications with high dynamic performance requirements, such as aircraft and rocket servo control, and turbine speed regulation. For applications with lower dynamic requirements, proportional valves are generally preferred.

Generally speaking, servo systems seem to be closed-loop control, while proportional systems are mostly used for open-loop control. Secondly, proportional valves come in more types, including proportional pressure and flow control valves, offering more flexible control than servo valves. Internally, servo valves are mostly zero-overlap, while proportional valves have a certain dead zone, resulting in lower control accuracy and slower response. However, looking at development trends, especially in proportional directional flow control valves and servo valves, the performance difference between the two is gradually narrowing. Furthermore, proportional valves are significantly cheaper than servo valves and have stronger resistance to contamination.

The Difference Between Servo Valves and Proportional Valves: There is no strict definition of the difference between servo valves and proportional valves. Because the performance of proportional valves is constantly improving and gradually approaching that of servo valves, proportional servo valves have emerged in recent years.

Proportional Valves and

Characteristics of Proportional Valves

Characteristics of PARKER Proportional Valves:

1) Enables stepless adjustment of pressure and speed, avoiding the shock phenomenon during directional switching of normally open on/off valves.

2) Enables remote and program control.

3) Compared to intermittent control, the system is simplified, and the number of components is greatly reduced.

4) Compared to hydraulic proportional valves, it is smaller, lighter, simpler in structure, and lower in cost, but its response speed is much slower than that of a hydraulic system, and it is more sensitive to load changes.

5) It uses less power, generates less heat, and produces less noise.

6) It will not cause a fire and will not pollute the environment. It is less affected by temperature changes.

Working Principle of a Proportional Valve

The command signal is amplified by a proportional amplifier and the current is output proportionally to the proportional electromagnet in the proportional valve. This proportionally moves the valve core, thus controlling the flow rate and direction of the fluid, thereby achieving position or speed control of the actuator. For applications requiring high position or speed accuracy, a closed-loop control system can be constructed by detecting the displacement or speed of the actuator.

PARKER

The company primarily deals in European and American brands and can source brands from any European country. For example, its key German brands include: BURKERT, DEMAG, HAWE, REXROTH, HYDAC, PILZ relays, FESTO, IFM sensors, E+H, HEIDENHAIN, P+F sensors, SICK, TURCK, and HIRSCHMANN industrial switches. German brands: Hengstler, Murr, Schmersal, Samson, EPRO (Emerson Group)

American brands: MOOG, ASCO, MAC, NUMATICS, PARKER, VICKERS

British brands: Helon Norgren

Italian brands: OMAL, ATOS, CAMOZZI, UNIVER, Camozzi