What are the functions of the hydraulic tank? What should I pay attention to when designing?

The hydraulic tank is a container used to store the oil needed to ensure the work of the hydraulic system. It is one of the indispensable components of the hydraulic system. Any hydraulic system can not work properly without the tank. Pay attention to the public number "hydraulic said" to get more hydraulic knowledge.

01

The function and structure of the Fuel Tank
In the hydraulic system, the oil tank is a functional component, and its functions are mainly:

Equilibrium pressure

When working, the oil volume in the hydraulic system will change, such as differential cylinder, thermal expansion and cold contraction, external leakage, etc. If you have a completely closed system, the pressure will drastically change. The oil tank holds the oil, directly or indirectly communicated with the atmosphere (see the figure below), which can keep the system's oil inlet and return pressure constant.

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1 filter screen, 2 partitions, 3 exhaust screen, 4 ventilation filter, 5 hydraulic system,

A suction port, B discharge port, C return port

Fuel tank

Store oil, distribute oil heat;

Separating bubbles in the oil, eliminating foam and precipitating impurities;

For the installation location of system components, there are many auxiliary components installed on the tank, such as coolers, heaters, air filters and level gauges. Pay attention to the public number "hydraulic said" to get more hydraulic knowledge.

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1 tank 2 cooler 3 High pressure filter 4 liquid level thermometer 5 High pressure pump

Medium power station

According to the structure, the fuel tank has two kinds of integrated and separate.

Integral hydraulic tank: Together with the mechanical equipment body, the cavity part of the main engine is used as the hydraulic tank. It is characterized by compact structure and easy recovery of various oil spills. However, the heat dissipation condition is not good, which is easy to cause thermal deformation of adjacent components, affecting the accuracy of mechanical equipment; The complexity of the main engine is increased, and the maintenance is inconvenient.

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Separate hydraulic tank: set separately from the main engine. Flexible layout, easy maintenance, can reduce the impact of fuel tank heating and hydraulic vibration on the working accuracy of the main engine, widely used, often used in walking machinery and fixed machinery system. Pay attention to the public number "hydraulic said" to get more hydraulic knowledge.

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02

How the fuel tank is installed

Independent tank is a very widely used type of tank, often used in industrial production equipment, usually made of rectangular shape. According to the different installation position can be divided into upper type, side type and lower type.

Top type

The hydraulic pump and other devices are installed on the upper cover plate with good stiffness, which is compact in structure and widely used. Heat fins can be cast on the tank shell to strengthen the heat dissipation effect, that is, to improve the service life of the hydraulic pump.

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Side mounted

The hydraulic pump and other devices are installed next to the tank, although the area is large, but the installation and maintenance are very convenient, usually used when the system flow and tank capacity are large, especially when one tank is used to supply oil to multiple hydraulic pumps. Because the oil level of the side-mounted tank is higher than the suction port of the hydraulic pump, it has a better suction effect.

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Bottom type

The hydraulic pump is placed under the tank, which is not only easy to install and maintain, but also greatly improves the suction capacity of the hydraulic pump.

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03

Design and selection of fuel tank

Custom hydraulic tanks have advantages over off-the-shelf tanks because they can be designed to fit the exact space and technical requirements required for optimal performance. Cost, size and weight can be minimized while maintaining performance and efficiency. Here are some factors to consider:

1. Fuel tank volume calculation

In order to better heat dissipation, the tank should have enough volume. In order to ensure that the oil in the hydraulic system will not leak when it flows back to the tank, the effective volume of the tank refers to the volume when the oil level is 80% of the tank height.

The effective volume of the tank should be calculated according to the principle of heat and heat dissipation balance of the hydraulic system. In order to better precipitate impurities and separate air, the effective volume of the tank is generally 2-7 times the volume of oil discharged by the hydraulic pump per minute. When the system is a low pressure system, take 2-4 times, when the system is a medium pressure, take 5-7 times, when the system is a high pressure, take 10-12 times, that is, you must ensure that there is enough oil.

Generally, the empirical formula V= (1.2~1.25) × ((0.2~0.33) ×Qb+Qg) is used, where Qb is the flow rate of the pump and Qg is the capacity of the hydraulic cylinder.

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2. Calculation of pressure drop

The pressure drop calculation is critical: at maximum pressure drop, enough fluid should be retained in the tank to provide a reasonable residence time for the fluid passing through the tank. The residence time gives the pollutants a chance to settle down and allow the bubbles to coalesce. A good rule of thumb is to keep the total capacity fixed at one-third of the maximum pump output when down.

3. Thermal expansion

When determining the size of the tank, the increased fluid volume due to heat must be taken into account. Fluid expansion must be considered between the tank filling with cold fluid and the fluid reaching its maximum operating temperature. Care should be taken to avoid overfilling when servicing the tank.

4. Location

The location of the tank is very important, and the main job of the tank is to supply oil to the pump. Therefore, the ideal location is close to the inlet of the pump and directly above it. Pay attention to the public number "hydraulic said" to get more hydraulic knowledge.

5. Oil port position

Another important design consideration is the location and size of the fuel tank inlet and outlet. Pump oil intake ports and system oil return ports should be located at opposite ends of the tank to allow the returned oil to lose heat before being sucked into the system again.

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To further maintain the temperature of the heater, keep the return oil away from the pump inlet and help prevent sloshing, the tank may be equipped with partitions. The spacer should be positioned to direct the returned oil to the tank wall, where the heat can be transferred to the atmosphere. The oil should take the longest possible route to the outlet of the tank. To prevent settling contaminants from entering the system, the tank outlet should be raised slightly from the bottom of the tank.