Performance requirements of Italian ATOS proportional valves

Brand

ATOS/Italian Atos

Performance Requirements of Italian ATOS Proportional Valves

ATOS Piston Pumps, ATOS Gear Pumps, ATOS Axial Piston Pumps, ATOS Vane Pumps, ATOS Hydraulic Cylinders

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Italian ATOS Proportional Valves - Electro-Proportional Valves

Automatic control can be divided into intermittent control and continuous control. Intermittent control is on/off control. Pneumatic control systems use 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 an output that changes proportionally to the input, with a certain proportional relationship between the two. Proportional control can be divided into open-loop and closed-loop control.

**ATOS Proportional Valve Structure and Principle (Italy)**

**ATOS Proportional Valve (Italy)**

When the input signal increases, the pilot valve 1 of the supply solenoid valve switches, while the exhaust solenoid pilot valve 7 is in the reset state. The supply pressure then enters the pilot chamber 5 from the SUP port through valve 1. The pressure in the pilot chamber 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 input signal. Because there is no nozzle-baffle mechanism, the valve is insensitive to impurities and has high reliability.

Features of Italian ATOS proportional valves:

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

2) Enables remote and program control.

3) Simplifies the system and greatly reduces the number of components compared to intermittent control.

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

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

The main valve of an Italian ATOS proportional valve is generally a spool valve structure, similar to a directional valve. However, the valve core is not driven by an electromagnet, but by the hydraulic pressure output from the pre-stage valve. This is similar to an electro-hydraulic directional valve, except that the pre-stage valve of an electro-hydraulic directional valve is an electromagnetic directional valve, while the pre-stage valve of a servo valve is a nozzle-flapper valve or jet valve with better dynamic characteristics.

In other words, the main valve of the Italian ATOS proportional valve is controlled by the output pressure of the pre-stage valve, and the pressure of the pre-stage valve comes from the inlet p of the servo valve. If the pressure at port p is insufficient, the pre-stage valve cannot output enough pressure to actuate the main valve spool.

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 pre-stage valve to actuate the main valve spool, and the entire servo valve fails. 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 pre-stage valve.

The Italian ATOS proportional valve actually has many disadvantages: high energy consumption, prone to failure, poor resistance to contamination, high price, etc. Its only advantage is that its 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 the dominant choice.

Generally speaking, Italian ATOS proportional valves are more commonly used in open-loop control systems than servo systems. Secondly, proportional valves offer a wider variety of types, including proportional pressure and flow control valves, providing more flexible control than servo valves. Internally, servo valves typically have zero override, while proportional valves have a certain dead zone, resulting in lower control accuracy and slower response. However, looking at development trends, especially in proportional 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.

Our business scope includes:

Hydraulic components:

Solenoid directional valves, directional valves, check valves, stack valves, relief valves, counterbalancing valves, proportional valves, manual directional valves, flow valves, pressure reducing valves,

Throttle valves, pressure control valves, back pressure valves, filling valves, flow dividers, shuttle valves, pressure relays, cartridge valves, pneumatic valves, piston pumps,

Gear pumps, vane pumps, cycloidal hydraulic motors, oil coolers, hydraulic cylinders, etc.;

Pneumatic components:

Air source processor assemblies, filters, pressure regulating valves, oil feeders, solenoid valves, pneumatic valves, angle seat valves, manual valves, hand-operated valves, foot valves,

Mechanical valves, check valves, vacuum generators, cylinders, magnetic switches, shock absorbers, pressure gauges, quick couplings, floating couplings,

Pressure gauge switches, water coolers, electric positioners, PU tubing, vacuum suction cups, oil filters, vibrators;

Electrical components:

Relays, sensors, converters, proximity switches, encoders, programmable logic controllers (PLCs); The company maintains a large inventory, with standard parts readily available. To better serve customers across various industries, the company also distributes other spare parts, utilizing professional sourcing channels and offering reasonable prices.

The company's products are widely used in industrial machinery, machine tools, plastics machinery, shoe machinery, brick machinery, metallurgy, mining, chemical industry, papermaking, coal industry, shipbuilding, power generation, construction machinery, environmental protection machinery, and many other fields.