Selection of hydraulic oil pump scheme
In this article, I will talk to you about the selection of hydraulic oil pump solutions with Hehydraulic Xiaobian. One of the decisive factors for a reasonable selection of hydraulic pump solutions is the cost of the entire system. Compared with expensive piston pumps, gear pumps and vane pumps have become the most popular choice for many applications due to their lower cost, simple circuit, and low filtration requirements. practical options for the occasion.
Priority flow control:
Regardless of the pump speed, working pressure or flow required by the branch, the fixed-value primary flow control valve can always ensure the flow required for the equipment to work. In this circuit, the output flow of the pump must be greater than or equal to the required flow of the primary oil circuit, and the secondary flow can be used for other purposes or returned to the oil tank. The fixed-value primary flow valve (proportional valve) combines the primary control with the hydraulic pump, which saves the pipeline and eliminates external leakage, thus reducing the cost. A typical application of this kind of gear pump circuit is the steering mechanism commonly seen on truck cranes, which eliminates a pump.
The function of the load sensing flow control valve is very similar to that of the fixed value primary flow control: that is, the primary flow is provided regardless of the pump speed, working pressure or the flow required by the branch. But only through the primary oil port to provide the required flow to the primary oil circuit, up to its maximum adjustment value. This circuit can replace the standard primary flow control circuit to obtain the maximum output flow. Because the pressure of the no-load circuit is lower than the fixed value primary flow control scheme, the temperature rise of the circuit is low and the no-load power consumption is small. Load-sensing proportional flow control valves, like primary flow control valves, are typically used in power steering.
Bypass flow control:
For bypass flow control, regardless of the pump speed or working pressure, the pump always supplies fluid to the hydraulic system at a predetermined maximum value, and the excess is discharged back to the oil tank or the inlet of the pump. This scheme limits the traffic entering the system for optimal performance. Its advantage is that the maximum adjustment flow can be controlled through the scale of the circuit, and the cost can be reduced; the pump and the valve are combined into one body, and the pressure of the circuit can be reduced to the minimum through the bypass control of the pump, thereby reducing the pipeline and its leakage.
Bypass flow control valves can be designed with mid-range load-sensing control valves that limit the operating flow (operating speed) range. This type of gear pump circuit is often used in refuse trucks or power steering pump circuits where the hydraulic manipulation is limited to get the engine to optimum speed, and it can also be used in stationary machinery!