The formation of foam in the hydraulic oil tank significantly affects the stability and lifespan of the hydraulic system. The root cause lies in the air mixed in the oil forming bubbles during flow, which are difficult to dissipate quickly. Optimizing the tank design through structural innovation can achieve systematic improvements in three aspects: bubble suppression, flow guidance, and accelerated defoaming. The following analysis focuses on key structural innovations.
Traditional oil tank return port designs often result in oil directly impacting the liquid surface, exacerbating air entrainment. New oil tanks optimize the return path by employing a structure combining a return oil filter and a spiral flow channel, allowing the return oil to flow along a specific path, avoiding direct impact on the bottom or surface of the tank. For example, the return oil filter can be designed for vertical installation, with the oil flowing from bottom to top and then from the inside to the outside into the return chamber, before entering the suction chamber through a notch at the top of the baffle. This design not only reduces bubbles generated by oil impact but also extends the oil circulation time within the tank, providing sufficient time for bubbles to rise naturally, thereby reducing the bubble content in the suction zone.
The baffle is a key structure within the oil tank separating the suction and return zones. Traditional baffles are mostly vertically designed, offering limited efficiency in separating fine air bubbles. The innovative design employs an inclined baffle, with its upper part tilted 15°~20° towards the oil suction chamber, creating a guiding channel for rising bubbles. This inclined baffle significantly improves bubble rising efficiency, allowing more bubbles to float to the surface before entering the oil suction zone. Furthermore, a gap is maintained between the lower end of the baffle and the bottom plate of the tank, facilitating the removal of tank deposits while preventing the baffle from completely blocking oil flow, ensuring smooth circulation.
The tank capacity and shape directly affect the oil flow pattern. Increasing the tank capacity reduces the oil flow rate and decreases bubbles generated by turbulence, but sacrifices equipment compactness. The innovative design achieves similar effects within a limited capacity by optimizing the internal structure of the tank. For example, a return oil chamber extends the oil circulation path, allowing the oil to flow fully between the return and suction chambers, enabling bubbles to rise naturally during this process. Simultaneously, the tank shape can be designed as a cuboid or near-cubic shape to avoid dead zones caused by sharp corners, ensuring uniform oil circulation.
Rapid bubble elimination relies on its efficient separation from the oil. The new oil tank incorporates a multi-layered purification structure between the oil inlet and outlet. For example, a first purification structure is fixed to the inner surface of the return pipe, and a second purification structure is installed at the top of the outlet pipe, performing multiple filtrations and defoaming processes on the oil. Furthermore, a metal mesh can be installed at the bottom of the tank to capture and break bubbles. The pore size and density of the metal mesh need to be optimized to balance the defoaming effect with oil flow resistance, preventing excessive resistance from causing a rise in system pressure.
The tank's sealing and breather design are crucial to preventing external air from entering. Traditional breathers are easily clogged by contaminants, leading to negative pressure inside the tank and exacerbating poor pump suction. The innovative design uses a high-efficiency air filter and optimizes the breather's position and structure to ensure efficient air separation. For example, the breather can be installed on top of the tank via a flange connection for easy disassembly and cleaning. Simultaneously, a sealing ring is used between the tank cover and the tank body; regular inspection and replacement of the seals prevent air from seeping in through gaps.
The ease of cleaning and maintenance of the hydraulic oil tank directly affects its long-term defoaming performance. An innovative design places both the return and suction ports on the bottom plate of the tank, serving as both oil inlet/outlet and cleaning port. This design facilitates the thorough removal of accumulated impurities and moisture from the tank, preventing contaminants from disrupting the oil's surface tension and causing stable foam formation. Furthermore, observation windows or level gauges can be installed on the tank sidewalls for real-time monitoring of the oil status, allowing for timely detection and intervention of foaming issues.
Reducing foam generation and defoaming time in hydraulic oil tanks through structural innovation requires a comprehensive approach, including optimizing the return path, improving baffle design, optimizing tank capacity and shape, strengthening bubble separation structures, upgrading seals and breather design, and enhancing cleaning and maintenance convenience. These innovative designs not only significantly reduce the impact of foam on the hydraulic system but also improve system efficiency and reliability, ensuring the long-term stable operation of hydraulic equipment.
