Common hydraulic terms and specialized terms for hydraulic accessories

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A hydraulic circuit is a component of a hydraulic system that consists of various hydraulic components and possesses certain functions; its schematic diagram is represented using hydraulic graphic symbols. A hydraulic station is a hydraulic power source device composed of a hydraulic pump, a drive motor, an oil tank, a relief valve, etc., or a hydraulic device that includes control valves. The rated pressure is the highest pressure at which the system can operate continuously. Back pressure refers to the pressure acting in the opposite direction of the oil return side or the pressure acting surface within the hydraulic circuit. Pressure shock is the maximum pressure increase that occurs during transitions. The opening pressure is the pressure at which a valve such as a check valve or relief valve starts to open when the pressure rises to a certain level; the closing pressure is the pressure at which such a valve starts to close when the inlet pressure drops to a certain level, causing the flow rate to decrease below a specified value. Rated flow rate refers to the flow rate that can be ensured under certain conditions. Flow rate generally refers to the volume of fluid discharged by a hydraulic pump per unit of time. For positive-displacement hydraulic pumps (or motors), it refers to the volume of fluid discharged (or absorbed) per rotation. Fluid power is the power possessed by a fluid; in the case of hydraulics, it is actually expressed as the product of flow rate and pressure. Pipelines and piping systems are used to convey working fluids; the main pipelines include the oil suction pipeline, the pressure pipeline, and the oil return pipeline. The oil drain pipeline refers to the pipeline through which oil is returned to the oil tank. Channels for conveying fluids exist inside components, either through machining or casting. Port openings are the openings in components through which fluids pass. Throttling is a mechanism that reduces the cross-sectional area of flow, thereby creating resistance inside pipelines or channels. This can be achieved through long-channel throttling or thin-edge throttling. In slide valve types, the valve core (cylindrical valve core) interacts with a cylindrical sliding surface; as it moves axially, it controls the opening and closing of the flow path. Oil drainage refers to the oil that returns from the channels (or pipes) within hydraulic components to the oil tank or collector. Leakage refers to a small amount of oil that escapes from areas that should remain sealed under normal conditions. Static seals are used in stationary parts to prevent fluid leakage, while dynamic seals are used to seal parts that move relative to each other. Fluid jamming occurs inside slide valve types due to uneven flow, resulting in an uneven pressure distribution on the central axis, which presses the valve core against the valve body (or sleeve), preventing it from functioning properly. Cavitation occurs when the pressure of the flowing fluid drops to the saturation vapor pressure or air separation pressure in certain areas, leading to the formation of bubbles due to the generation of vapor and the separation of dissolved air. When bubbles collapse during flow, extremely high pressures occur in localized areas, leading to phenomena such as noise and flow rate fluctuations. In speed control valves (flow control valves with pressure compensation), when fluid starts to flow, the flow rate momentarily exceeds the set value; this phenomenon is known as fluttering. To reduce the effects of friction and fluid sticking on slide valve-type valves and to improve their performance, higher-frequency vibrations are applied. Hydraulic balancing uses hydraulic pressure to balance the loads (including the equipment itself). Fluid power transmission devices are those that use fluid as a medium to transmit power. There is the inlet throttling method, where the throttle valve is installed in the pipeline on the inlet side of the actuator, and the operating speed is adjusted through throttling. There is also the outlet throttling method, in which the throttle valve is placed in the pipeline on the outlet side of the actuator, again using throttling to adjust the operating speed. The bypass throttling method involves directing a portion of the flow toward the actuator, with the rotor pump returning fluid to the tank through a throttle valve installed in the bypass pipeline, thereby adjusting the operating speed of the actuator. The electro-hydraulic method combines electrical components such as electromagnets with hydraulic controllers. The pilot control method relies on pressure introduced by pilot valves for control. Hydraulic power transmission devices are those that utilize the pressure energy of fluids to transmit power. In such devices, positive-displacement hydraulic pumps and hydraulic actuating elements (hydraulic cylinders or hydraulic motors) are used. Common hydraulic terms – hydraulic accessories and other specialized terms: Filters are components that use filtration to remove solid particles from fluids. Pipe filters are used in pipelines; tank filters fall into this category as well, aside from those used in pressure pipelines and vent lines. Accumulators are containers that store liquid under pressure, with this stored liquid dapat be used as a temporary source of power. Pressure relays are components that cause electrical contacts to activate when the fluid pressure reaches a predetermined value. Hose assemblies consist of pressure-resistant hoses with hose fittings at both ends; these fittings are used to connect pipelines or attach them to hydraulic elements. They represent a general term for connectors that can be installed and removed within fluid pathways. Hydraulic tanks are containers used to store hydraulic oil. The connections between the tank bottom plate and pipelines are concentrated on one side, and control valves are mounted there using seals. Auxiliary plates, also known as circuit boards (integrated blocks), have channels that serve as pipelines inside them, with hydraulic components installed on the outside, along with various connection ports. Working fluid refers to the liquid used in hydraulic equipment or systems. Hydraulic oil is the fluid used in hydraulic equipment. There are also other types of liquids. Flame-retardant hydraulic oil is a type of hydraulic oil that is difficult to ignite, thereby helping to prevent fires to the greatest extent possible