ATOS proportional valve DHZO-A-071-L1 available in Shanghai.

Brand

ATOS/Italian Atos

ATOS proportional valves from Italy control flow in two ways: On-off control and Continuous control. On-off control means the valve is either fully open or fully closed, with the flow rate either at its maximum or minimum, without intermediate states. Examples include common solenoid direct-flow valves, solenoid directional valves, and electro-hydraulic directional valves. Continuous control allows the valve to open to any desired degree, thus controlling the flow rate. These valves can be manually controlled (e.g., throttle valves) or electrically controlled (e.g., proportional valves and servo valves). Therefore, the purpose of using proportional or servo valves is to achieve throttling control of flow rate electrically (and, with structural modifications, pressure control, etc., can also be achieved). Since it's 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 upstream control circuit.

ATOS Proportional Valve Overview:

ATOS Proportional Valve Product Advantages and Disadvantages

The main valve of a servo valve generally has a spool valve structure, similar to a directional valve. However, the valve core's switching 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 electromagnetic directional 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. As 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.

ATOS proportional valve features:

1) Enables stepless adjustment of pressure and speed, avoiding the shock phenomenon during switching of normally open on/off pneumatic 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 than hydraulic systems, and it is more sensitive to load changes.

5) Low power consumption, low heat generation, and low noise.

6) No fire hazard and no environmental pollution. Less affected by temperature changes.

Commonly used models of ATOS proportional valves are as follows:

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

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We also have companies in the US, such as ASCO, VICKERS, MAC, PARKER, MOOG, FAIRCHILD, DENISON, ROSS, UE, MTS, and GEFRAN. We have the agency rights for Japanese brands, such as CKD, TOYOOKI, NACHI, DAIKIN, SMC, KOGANEI, TACO, NOK, TOKIMEC, and other brands.