Analysis of Hydraulic Circuit Design and Development of Gear Pump Function (2)

Priority Flow Control Regardless of pump speed, working pressure or branch flow required size, the value of a flow control valve can always ensure the required flow of equipment. In this circuit, the pump output flow must be greater than or equal to the required flow of the oil circuit, the secondary flow can be used for it or back to the tank. Setting a flow valve (proportional valve) will be a combination of control and hydraulic pump, eliminating pipelines and eliminate external leakage, so reduce the cost. A typical application of such a gear pump circuit is the steering mechanism often found on truck cranes, which eliminates the need for a pump. Load sensing flow control valve function and set a value of flow control function is very similar: no matter the pump speed, working pressure or branch pumping demand flow size, provide a flow. However, the required flow rate is only provided to the primary circuit through one port up to its maximum adjustment. This circuit replaces the standard primary flow control loop for maximum output flow. Due to no-load circuit pressure is lower than the value of a flow control program, so the loop temperature low, no load power consumption. Load sensing than the flow control valve and a flow control valve, its typical application is power steering. Bypass Flow Control For bypass flow control, the pump always supplies fluid to the system at a predetermined maximum regardless of pump speed or operating pressure, with the excess drained to the tank or pump inlet. This scenario limits the amount of traffic that enters the system to give it the best performance. This has the advantage of reducing the cost by controlling the maximum flow rate through the loop size; combining the pump and the valve and bypassing the pump to minimize the loop pressure, thereby reducing tubing and leakage. The bypass flow control valve can be designed with a medium-duty load-sensing control valve that defines the range of working flows (operating speeds). Gear pump circuits of this type are commonly used in landfill trucks or power steering pump circuits that limit the hydraulic operation for optimum engine speed and also for stationary machinery. Dry Suction Valve Dry Suction Valve is a pneumatic control hydraulic valve used to pump into the oil throttling, when the device is under no-load hydraulic flow, only a very small flow (<18.9t / min) through the pump; With load, full flow suction pump. This circuit eliminates the need for a clutch between the pump and the prime mover, reducing costs and reducing no-load power consumption by maintaining the plant's prime mover power with minimal flow through the circuit. In addition, it also reduces the pump noise at no load. Dry suction valve circuit can be used in any vehicle driven by the internal combustion engine hydraulic system, such as refuse trucks and industrial equipment. The choice of hydraulic pump solution At present, the working pressure of the gear pump is close to that of the piston pump, and the combined load sensing scheme offers the possibility of variable gear pump. This means that the originally clear boundary between the gear pump and the piston pump More and more fuzzy Reasonable choice of one of the decisive factors in the hydraulic pump solution is the cost of the entire system. Compared with the expensive piston pump, the gear pump is feasible in many applications due to its low cost, simple circuit and low filtration requirements The choice of program.