Selection criteria for ATOS solenoid valves

The performance of ATOS proportional directional valve is between servo valve and proportional valve.

ATOS proportional directional valve is a type of proportional valve used to control flow and direction.

Extended information - Automatic control of electrical proportional valves can be divided into intermittent control and continuous control. Intermittent control refers to switch control. In pneumatic control systems, on-off directional valves with lower operating frequencies are used to control the on/off of the pneumatic circuit. Adjust the required pressure with a pressure reducing valve and adjust the required flow rate with a throttle valve. This traditional pneumatic control system requires multiple pressure reducing valves, throttle valves, and directional valves in order to have multiple output forces and multiple motion speeds. In this way, not only do the components need to be numerous, the cost is high, and the system is complex, but many components also require manual adjustment in advance. Electric proportional valve control belongs to continuous control, which is characterized by the output quantity changing with the input quantity, and there is a certain proportional relationship between the output quantity and the input quantity. Proportional control can be divided into open-loop control and closed-loop control.

Structure principle of ATOS proportional directional valve

As the input signal increases, the supply solenoid valve pilot valve 1 changes direction, while the exhaust solenoid pilot valve 7 is in the reset state. The supply pressure enters the pilot chamber 5 through valve 1 from the SUP port, and the pilot chamber pressure rises. The air pressure acts on the top of diaphragm 2, and the supply valve core 4 connected to diaphragm 2 opens, while the exhaust valve core 3 closes, generating output pressure. This output pressure is fed back to control circuit 8 through pressure sensor 6. Here, a quick comparison correction is made with the target value until the output pressure is proportional to the input signal, thereby obtaining a change in output pressure proportional to the change in input signal. Due to the absence of a nozzle baffle mechanism, the valve is insensitive to impurities and has high reliability.

Characteristics of ATOS proportional directional valve

1) It can achieve infinite adjustment of pressure and speed, avoiding the impact phenomenon when the normally open switch air valve changes direction.

2) Can achieve remote control and program control.

3) Compared with intermittent control, the system is simplified and the components are greatly reduced.

4) Compared with hydraulic proportional valves, they have smaller volume, lighter weight, simpler structure, and lower cost, but their response speed is much slower than hydraulic systems and they are also more sensitive to load changes.

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

6) No fire, no pollution to the environment. Less affected by temperature changes.

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

ATOS proportional directional valve means that the main valve of the servo 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 push the main valve core to move.

We know that when the load is zero, if the four-way spool valve opens, the p-port pressure=t-port pressure+valve port pressure loss (ignoring other pressure losses on the oil circuit). If the valve port pressure loss is very small and the t-port pressure is zero, then the p-port pressure is not enough to supply the pre stage valve to push the main spool, and the entire servo valve fails. So the valve port of the servo valve is made too small, 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 ATOS proportional directional valve actually has many disadvantages, such as high energy consumption and waste, easy failure, poor pollution resistance, high price, etc. The only benefit is that its dynamic performance is the highest among all hydraulic valves. With this advantage, servo valves have to be used in many situations that require high dynamic characteristics, such as servo control of aircraft rockets, turbine speed regulation, and so on. Those with lower dynamic requirements are basically dominated by proportional valves.

Generally speaking, ATOS proportional directional valves are used for closed-loop control in servo systems, while proportional valves are mostly used for open-loop control; Secondly, there are many types of proportional valves, such as proportional pressure and flow control valves, which are more flexible in control than servos. From their internal structure, servo valves are mostly zero covered, while proportional valves have a certain dead zone, low control accuracy, and slow response. But from the perspective of development trends, especially in the aspect of proportional flow control valves and servo valves, the performance difference between the two is gradually narrowing. In addition, the cost of proportional valves is much lower than that of servo valves, and their anti pollution ability is also strong!

The difference between ATOS proportional directional valve and servo valve is not strictly regulated, because the performance of proportional valve is getting better and gradually approaching servo valve, so proportional servo valve has emerged 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-to- 173 -l 5 / by-m / 7

DKZO-A-151-S5

DKZO-A-171-L5

DKZO-A-173-S5

Dkzor-a- 151 -s 5

Dkzor-a- 151 -s 5 / 18 40

DKZOR-A-151-S5/B

DKZOR-A-153-L5/B

DKZOR-A-171-D5 40

DKZOR-A-171-L5

Dkzor-a- 171 -s 5

Dkzor-a- 171 -s 5 / 18

DKZOR-A-173-D5

DKZOR-A-173-L5

DKZOR-A-173-L5/18 40

DKZOR-A-173-L5/Y

Dkzor-a- 173 -s 3

Dkzor-a- 173 -s 5

Dkzor-a- 173 -s 5 / 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 -l 5 40

Dkzor-te- 171 -l 5

DKZOR-TE-171-L5/I 40

DKZOR-TE-171-S5

Selection criteria for ATOS solenoid valves：

　　ATOS solenoid valveSelection criteria:

1. Select the solenoid valve based on pipeline parameters: diameter specification (i.e. DN), interface method

1) Determine the diameter (DN) size according to the on-site pipeline inner diameter size or flow requirements;

2) Interface method, generally>DN50 requires flange interface, ≤ DN50 can be freely selected according to user needs.

2. Select the material and temperature group of the solenoid valve based on fluid parameters

1) Corrosive fluids: corrosion-resistant solenoid valves and all stainless steel should be selected; Edible ultra clean fluid: It is recommended to use food grade stainless steel solenoid valves;

2) High temperature fluid: It is necessary to choose electromagnetic valves made of high-temperature resistant electrical materials and sealing materials, and to choose piston type structures;

3) Fluid state: up to gaseous, liquid, or mixed state, especially when the diameter is greater than DN25, it must be distinguished;

4) Fluid viscosity: Usually below 50cSt, it can be freely selected. If it exceeds this value, a high viscosity solenoid valve should be used.

3. Selecting solenoid valves based on pressure parameters: principles and structural types

1) Nominal pressure: This parameter has the same meaning as other general valves and is determined based on the nominal pressure of the pipeline;

2) Work pressure: If the work pressure is low, the principle of direct action or step-by-step direct action must be selected; When the low working pressure difference is above 0.04Mpa, direct acting, step-by-step direct acting, and pilot operated can all be selected.

4. Electrical selection: The voltage specifications should preferably be AC220V or DC24, which are more convenient.