ATOS proportional directional valve QVHZO-A06-12 available in Shanghai.
$401.73
The purpose of Italian ATOS proportional directional valves or servo valves is to achieve flow throttling control through electronic means (of course, pressure control can also be achieved through structural modifications). Since it is throttling control, there will inevitably be energy loss. The difference between servo valves and other valves is that their energy loss is greater because they require a certain flow to maintain the operation of the pre-stage control circuit.
Brand
ATOS/Italian Atos
The main valve of an ATOS proportional directional valve is generally a spool valve, similar to a directional control valve. However, the valve spool 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 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 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 pilot valve to actuate the main valve spool, 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.
ATOS proportional directional 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 servo valves necessary 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 have more types, including proportional pressure and flow control valves, offering 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 structural principle of the ATOS proportional directional valve:
When the input signal to the ATOS proportional directional valve 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 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 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 Stock List:
Proportional Directional Valve DPZO-A-373-D5/E30
Proportional Directional Valve DPZO-AE-171-S5/E
Proportional Directional Valve DPZO-AE-171-S5/E
Proportional Directional Valve DPZO-AE-171-S5/G
Proportional Directional Valve DPZO-AE-171-S5/G +SP-ZH-7P
Proportional Directional Valve DPZO-AE-171-L5/E
Proportional Directional Valve DPZO-AE-173-S5
Proportional Directional Valve DPZO-AE-271-L5
Proportional Directional Valve DPZO-AE-271-L5
Proportional Directional Valve DPZO-AE-271-L5
Proportional Directional Valve DPZO-AE-273-L5
Proportional Directional Valve DPZO-AE-273-L5
Proportional Directional Valve DPZO-AE-373-S5
Proportional Directional Valve DPZO-AE-373-S5
Proportional Directional Valve DPZO-AES-PS-273-L5/IZ
Proportional Directional Valve DPZO-TE-173-S5/I
Proportional Directional Valve DPZ0-TE-271-L5/D
Proportional Directional Valve DPZO-L-271-L3
Proportional Directional Valve DPZO-L-273-L5
Proportional Directional Valve DPZO-LE-270-S5/G
Proportional Directional Valve DPZO-LE-271-L5
Proportional Directional Valve DPZO-LE-271-L5
Proportional Directional Valve DPZO-LE-271-L5/D
Proportional Directional Valve DPZO-LE-271-L5/D/I
Proportional Directional Valve DPZO-TE-271-S5 40
Proportional Directional Valve DPZO-A-271-L5/DEG
Proportional Directional Valve DPZO-A-273-D5/D/G
Proportional Directional Valve DPZO-A-273-D5/E30
Proportional Directional Valve DPZO-A-273-S5
Proportional Directional Valve DPZO-A-371-L5/DG
Proportional Directional Valve DPZO-A-373-D5/E30
Proportional Directional Valve DPZO-TE-171-L5
Proportional Directional Valve DPZO-AE-171-S5/E
Proportional Directional Valve DPZO-AE-171-S5/G
Proportional Directional Valve DPZO-AE-171-S5/G +SP-ZH-7P
Proportional Directional Valve DPZO-AE-171-L5/E
Proportional directional valve DPZO-AE-173-S5
Proportional directional valve DPZO-AE-271-L5
Proportional directional valve DPZO-AE-273-L5
Proportional directional valve DPZO-AE-273-L5
Proportional directional valve DPZO-AE-373-S5
Proportional directional valve DPZO-AES-PS-273-L5/IZ
Proportional directional valve DPZO-TE-171-L5
Proportional directional valve DPZO-TE-173-S5/I
Proportional directional valve DPZO-TE-271-L5/D
ATOS proportional directional valves can be divided into two types: one is on/off control: either fully open or fully closed, the flow rate is either maximum or minimum, with no intermediate state, such as ordinary solenoid straight-through valves, solenoid directional valves, and electro-hydraulic directional valves. Another type is continuous control: the valve port can be opened 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 valves or servo valves is to achieve flow control through electrical means (of course, pressure control can also be achieved through structural modifications). Since it is flow control, there will inevitably be 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.
The company mainly deals with European and American brands and can source brands from any European country. For example, our key German brands include: BURKERT, DEMAG, HAWE, REXROTH, HYDAC, PILZ relays, FESTO, IFM sensors, E+H, HEIDENHAIN, P+F sensors, SICK, TURCK, and HIRSCHMANN industrial switches. German brands: Hengstler, Murr, Schmersal, Samson, EPRO (Emerson Group)
American brands: MOOG, ASCO, MAC, NUMATICS, PARKER, VICKERS, ROSS
British brands: Norgren
Italian brands: OMAL, ATOS, CAMOZZI, UNIVER, Camozzi
