ATOS proportional directional valve DPZO-LES-PS-271-D5/IQ in stock

Brand

ATOS/Italian Atos

ATOS Piston Pumps, ATOS Gear Pumps, ATOS Axial Piston Pumps, ATOS Vane Pumps, ATOS Hydraulic Cylinders, ATOS Relief Valves, ATOS Proportional Valves

ATOS proportional directional valves control flow in two ways: One is on/off control: either fully open or fully closed, with flow either at its maximum or minimum, without intermediate states, such as ordinary solenoid direct-flow valves, solenoid directional valves, and electro-hydraulic directional valves. The other is continuous control: the valve port can open to any degree as needed, thereby controlling the flow rate. These valves can be manually controlled, such as throttle valves, or electrically controlled, such as proportional valves and servo valves. Therefore, the purpose of using proportional or servo valves is to achieve flow throttling control electronically (of course, pressure control can also be achieved through structural modifications). Since it is throttling control, there is inevitably energy loss. Servo valves differ from other valves in that their energy loss is greater because they require a certain flow rate to maintain the operation of the pre-stage control circuit.

Advantages and disadvantages of ATOS proportional directional valves:

The main valve of an ATOS proportional directional valve is generally a spool valve, similar to a directional control valve. However, the valve core is not driven by an electromagnet, but by the hydraulic pressure output from the pilot valve. This is similar to an electro-hydraulic directional control valve, except that the pilot valve of an electro-hydraulic directional control valve is an electromagnetic directional control valve, 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 core.

We know that when the load is zero, if the four-way spool valve is open, the pressure at port p = the pressure at port t + the 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 core, and the entire servo valve fails. Therefore, servo valves have relatively small orifices, requiring a certain pressure loss even when fully open to maintain the normal operation of the pre-stage valve.

Servo valves actually have many disadvantages: high energy consumption, prone to failure, poor contamination resistance, high price, etc. Their only advantage is their highest dynamic performance among all hydraulic valves. This single advantage makes them indispensable in many applications with high dynamic performance requirements, such as aircraft and rocket steering, and turbine speed control. 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 offer more variety, including proportional pressure and flow control valves, providing 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 contamination resistance!

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 has improved, they are gradually approaching that of servo valves, leading to the emergence of proportional servo valves in recent years.

The difference between ATOS proportional directional valves and servo valves:

ATOS proportional directional valves are mainly distinguished by the following points:

1. Different drive devices. The drive device for proportional valves is a proportional solenoid; the drive device for servo valves is a force motor or torque motor;

2. Different performance parameters. 2.1 Servo valves have no dead zone in the neutral position, while proportional valves do. Therefore, their applications differ. Servo valves and servo proportional valves are mainly used in closed-loop control systems, while other proportional valve structures are mainly used in open-loop control systems and closed-loop speed control systems.

2.2 Servo valves have a higher frequency response (response frequency), reaching up to around 200Hz, while proportional valves generally have a maximum frequency of tens of Hz.

2.3 Servo valves have higher requirements for hydraulic fluid, requiring fine filtration to prevent clogging, while proportional valves have lower requirements.

3. Valve core structure and machining precision differ. Proportional valves use a valve core + valve body structure, with the valve body also serving as the valve sleeve. Servo valves and servo proportional valves use a valve core + valve sleeve structure.

4. Neutral position functions differ. Proportional directional valves have neutral position functions similar to ordinary directional valves, while servo valves only have an O-type neutral position function (E-type for Rexroth products).

5. Rated pressure drop differs.

The performance of ATOS proportional directional valves falls between that of servo valves and proportional valves.

ATOS proportional directional valves are a type of proportional valve used to control flow rate and direction.

Further information---Automatic control of electro-proportional valves can be divided into intermittent control and continuous control. Intermittent control is also known as on-off control. Pneumatic control systems use on-off (ON-OFF) directional valves with low operating frequencies to control the opening and closing of the air path. Pressure reducing valves regulate the required pressure, and throttle valves regulate the required flow rate. This traditional pneumatic control system requires multiple pressure reducing valves, throttle valves, and directional valves to achieve multiple output forces and multiple movement speeds. This not only increases the number of components, raising costs and complicating the system structure, but also requires many components to be manually adjusted in advance. Electro-proportional valve control is a type of continuous control, characterized by the output changing with the input, and a certain proportional relationship exists between the output and input. Proportional control is divided into open-loop control and closed-loop control.

ATOS Proportional Directional Valve Structure and Principle

When the input signal to the ATOS proportional directional valve increases, the pilot valve 1 of the supply solenoid valve switches direction, while the exhaust solenoid pilot valve 7 remains in the reset state. The supply pressure then enters the pilot chamber 5 from the SUP port through valve 1. The pilot chamber pressure rises, and this pressure acts on the diaphragm 2, opening the supply valve core 4 connected to diaphragm 2 and closing the exhaust valve core 3, generating output pressure. This output pressure is fed back to the control loop 8 via pressure sensor 6. Here, a rapid comparison and correction is performed with the target value until the output pressure is proportional to the input signal, thus demonstrating that the output pressure changes proportionally to the change in the input signal. Because there is no nozzle-baffle mechanism, the valve is insensitive to impurities and has high reliability.

DKZO-A-151-S5

DKZO-A-171-L5

DKZO-A-173-S5

DKZOR-A-151-S5

DKZOR-A-151-S5/18 40

DKZOR-A-151-S5/B

DKZOR-A-153-L5/B

DKZOR-A-171-D5 40

DKZOR-A-171-L5

DKZOR-A-171-S5

DKZOR-A-171-S5/18

DKZOR-A-173-D5

DKZOR-A-173-L5

DKZOR-A-173-L5/18 40

DKZOR-A-173-L5/Y DKZOR-A-173-S3

DKZOR-A-173-S5

DKZOR-A-173-S5/18

DKZOR-AE-171-L5 10

DKZOR-AE-171-S5

DKZOR-AE-171-S5 10/WG

DKZOR-AE-171-S5/Y 10

DKZOR-AE-173-D5 10

DKZOR-AE-173-L5 10

DKZORC-A-151-S5/18

DKZOR-T-151-L5

DKZOR-T-151-L5/Y

DKZOR-T-153-L5

DKZOR-T-171-D5

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

2) Enables remote and program control.

3) Compared to intermittent control, the system is simplified, with a significant reduction in components.

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

5) Requires less power, generates less heat, and produces less noise.

6) Does not cause fires and does not pollute the environment. Less affected by temperature changes.