Could you tell me what are the types of unloading valve?
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Release Time：2021-05-21
The unloading channel and pressure valve are set up separately. During unloading, each spool is in the neutral position, and the oil from the oil source is discharged back to the oil tank through a special oil passage that runs through each valve, and the unloading oil passage runs through each reversing valve. When any one of the valves is working (I. e., cut off the unloading oil passage). The oil from the oil source enters the controlled actuator from the reversing valve, and the working pressure is limited by the pressure valve in the figure.
Through
The unloading channel and pressure valve are set up separately. During unloading, each spool is in the neutral position, and the oil from the oil source is discharged back to the oil tank through a special oil passage that runs through each valve, and the unloading oil passage runs through each reversing valve. When any one of the valves is working (I. e., cut off the unloading oil passage). The oil from the oil source enters the controlled actuator from the reversing valve, and the working pressure is limited by the pressure valve in the figure. The advantage of using this kind of unloading method is that when the valve stem moves from the neutral position to the working position, the unloading oil passage is gradually closed, the amount of oil entering the actuator gradually increases, the system pressure gradually increases, and the actuator starts smoothly, no impact, and has certain speed regulation performance, and the pressure valve structure is simple. The disadvantage is that the unloading oil channel is long and the pressure loss is large, especially when the number of reversing valves is large, the disadvantages are more prominent, and the unloading method is mostly used in occasions with fewer roads.
unloading type
This kind of unloading method is divided into two kinds
1. Unloading through controlled unloading valve
Unloading valve and safety valve as a whole, the composition of the pilot pressure valve, the valve is the unloading valve is a safety valve, sometimes is the overflow valve. During unloading, the control oil passage runs through each reversing valve, which is the same as the aforementioned unloading oil passage. When each directional valve is in the neutral position, the control oil passage of the unloading valve runs through each directional valve and communicates with the oil tank. When unloading, most of the oil is unloaded, the passage is short, and the pressure loss is low. When any road valve is reversed, the control oil passage is cut off, and the oil from the oil source enters the actuator from the reversing valve to work, and the working pressure is controlled by the pilot valve. At this time, the system pressure is the pilot valve adjustment pressure. This kind of unloading mode, even if the number of reversing valves increases, only the control oil passage increases, the unloading pressure increases little, and the unloading pressure is always kept low. This unloading mode is mostly used for manual reversing valves, and the unloading is reliable.
2, Solenoid valve controlled unloading valve unloading
This kind of unloading method is different from the previous one in that it controls whether the oil passage and the oil tank are on or off. It is controlled by a solenoid valve. The unloading oil passage is short, the pressure loss during unloading is low, and it is convenient for automatic control, but the reliability of unloading is low., Mostly used in the occasion of electromagnetic multi-way valves.
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2026/02/28
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