Brand

ATOS

ATOS proportional directional valves offer performance between servo valves and proportional valves.

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

Extended Information—Automatic control of electro-proportional valves can be divided into intermittent control and continuous control. Intermittent control is 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 is adjusted by pressure reducing valves, and flow rate is adjusted by throttle valves. 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, but also requires many components to be manually adjusted in advance. Electro-proportional valve control is a type of continuous control, characterized by output changing with 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 increases, the pilot valve 1 of the supply solenoid valve switches, 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 the air pressure acts on the diaphragm 2, causing the supply valve core 4 connected to diaphragm 2 to open, while the exhaust valve core 3 closes, 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.

ATOS Proportional Directional Valve Features

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

2) Enables remote control 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 hydraulic systems, 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.

The main valve of an ATOS proportional directional valve is generally a spool valve structure, similar to other directional valves. However, the valve core is not driven by an electromagnet, but by the hydraulic pressure output from the pilot valve. This is similar to electro-hydraulic directional valves, 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-flapper valve or jet valve with better dynamic characteristics.

In other words, the main valve of an ATOS proportional directional 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 p is insufficient, the pilot valve cannot output enough pressure to drive the main valve core.

The ATOS proportional directional valve, as we know, when the load is zero, 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 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 pilot valve.

The ATOS proportional directional valve actually has many disadvantages: high energy consumption, prone to failure, poor contamination resistance, high price, etc. Its only advantage is its highest dynamic performance 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, ATOS proportional directional valves are similar to servo valves, which are mostly used for closed-loop control, while proportional valves are primarily 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 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 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 ATOS proportional directional valves and servo valves is not strictly defined. As the performance of proportional valves improves, they are gradually approaching that of servo valves, leading to the emergence of proportional servo valves in recent years.

ATOS proportional directional valve model table:
DHZO-TE-051-L5/Y 40
DHZO-TE-071-L5
DHZO-TE-071-S5 40/PE
DHZO-TE-073-S5
DKZA-A-173-L5/PA-M/7
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

DKZOR-T-171-L5

DKZOR-T-171-S5

DKZOR-T-171-S5/Y

DKZOR-T-173-L5 40

DKZOR-TE-170-L5 40

DKZOR-TE-171-L5

DKZOR-TE-171-L5/I 40

DKZOR-TE-171-S5

ATOS Solenoid Valve Selection Criteria

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ATOS Solenoid Valve

Selection Criteria: 1. Selecting a Solenoid Valve Based on Pipeline Parameters: Nominal Diameter (DN) and Connection Type

1) Determine the nominal diameter (DN) based on the inner diameter of the pipeline or flow requirements.

2) For connection type, generally, valves with a diameter > DN50 should be selected; for diameters ≤ DN50, the choice is flexible based on user needs.

2. Selecting a Solenoid Valve Based on Fluid Parameters: Material and Temperature Group

1) Corrosive fluids: Corrosion-resistant solenoid valves and all-stainless steel valves are recommended; Ultra-clean edible fluids: Food-grade stainless steel solenoid valves are recommended.

2) High-Temperature Fluids: Solenoid valves made with high-temperature resistant electrical and sealing materials should be selected, and piston-type valves are preferred.

3) Fluid State: Fluids can be gaseous, liquid, or mixed, especially for diameters greater than DN25, where differentiation is crucial.

4) Fluid Viscosity: Generally, any choice is acceptable below 50 cSt; if this value is exceeded, a high-viscosity solenoid valve should be selected. 3. Selecting Solenoid Valves Based on Pressure Parameters: Principle and Structural Types

1) Nominal Pressure: This parameter has the same meaning as other general-purpose valves, determined by the nominal pressure of the pipeline;

2) Working Pressure: If the working pressure is low, a direct-acting or step-direct-acting principle must be selected; when the minimum working pressure difference is above 0.04 MPa, direct-acting, step-direct-acting, and pilot-operated valves can all be selected.

4. Electrical Selection: For voltage specifications, AC220V and DC24V should be prioritized for convenience.