Introduction
Multi-circuit commutation valve is a combination valve for two and more reversing valves. The reversing valve is a valve class that is connected to the airway of the valve body by means of a relative movement between the spool and the valve body. According to different work requirements, an accessory valve such as a safe relief valve, a one-way valve, and a fuel valve can be combined. Compared to other types of valves, the multi-circuit commutation valve has a small structure of compact pressure, and there is no advantage in the slider moving resistance, multi-bit function, long life, simple manufacturing.
Structure Type
Multi-circulation valve is combined with two or more valve blocks to manipulate a plurality of exercise of the actuette. It can combine the safety valve, overload valve, fuel valve, split valve, brake valve, a single-way valve, etc. according to the requirements of different hydraulic systems, so it is compact, simple line, and the pressure loss is small. Simple installation, therefore in engineering machinery, lifting machinery, and other required operations of multiple implementation element movements.
Multi-channel replacement valve has two types of integral and fragmentation (combined); according to oil connection, multi-channel valves can be divided into parallel, series, string parallel and composite oil; uninstalled There are two ways to uninstall the median unloading and safety valve.
Basic control strategy
Two basic control strategies of double-valve core multi-circuit commutation valves. Due to the flexibility of the multi-circuit commutation valve double valve core to two oil port control, the two port can be taken separately by flow control, pressure control or flow pressure control.
(1) Multi-channel replacement valve load direction remains unchanged throughout the operation
We know that for automotive cranes, excavators, loaders, etc. The tank is always unchanged during the entire working process. The following is the control strategy of the dual-valve core as an example with a crane becoming hydraulic cylinder.
Crane becomes in the working process, the load direction always remains the same, so we can take the hydraulic cylinder with a rod-resistant pressure control, a control strategy for flow control.
The rod-free flow control is calculated by detecting the pressure difference between the two sides of the non-rod-free side valve, and then calculates the size of the spool opening size according to the required flow or flowing flow; there is a rod cavity The side is controlled, so that the side maintains a low value pressure, making it more energy efficient and efficient.
Since we use traffic control in the rod-like cavity, the balancing valve used in the original control system can be replaced with a hydraulic one-way valve. This eliminates the system stability due to the unstable system caused by the balancing valve.
(2) Multi-channel replacement valve load direction changes during operation, in this case, "oil-type pressure control, oil-side flow control", in the hydraulic cylinder The side is controlled by pressure, and there is flow control on the rodless side side. If the load direction is unchanged, due to the flow control side, we can replace the two-way balance valve with a hydraulic check valve, thereby increasing the stability of the system. The oil side is used to maintain a lower reference pressure, on the one hand, improve system efficiency, and on the other hand, the system does not occur.
Multi-channel replacement valve In order to make a working mechanism that changes in the load direction can be well controlled, another PI controller will be applied to a pressure controller with a rod cavity, and after the load direction changes, The pressure of the rod cavity will be reduced; if there is still a rod cavity to maintain a low pressure, the hydraulic cylinder will move in the opposite direction when the load is large. At this time, we can use the added PI controller to monitor changes in the rod pressure. When the PI controller detects that the non-rod-free pressure is lower than the set reference value, the multi-channel commutation valve will increase the rod cavity pressure control. The pressure set by the device ensures the normal operation of the system.