Roadheader Knowledge (Part 2)

(1) The temperature rise of the fuel tank is serious

The fuel tank of the tunneling boring machine acts as a "hot flywheel", which can absorb heat in a short period of time and can also prevent the hydraulic system in a cold environment from being over-cooled when it is idling. The main contradiction of the fuel tank is temperature rise. When the temperature rises to a certain range, the balance no longer rises. Severe blast will cause various failures of the hydraulic system.

The reasons for the serious temperature rise of the fuel tank are:

①The fuel tank is set near the high temperature heat radiation source, and the ambient temperature is high;

②Various pressure losses in the hydraulic system (such as overflow, decompression, etc.) produce large energy conversion;

③Insufficient heat dissipation area when designing the fuel tank;

④ The viscosity of the oil is not selected properly, too high or too low.

The solution to the serious temperature rise of the stain box is:

① Avoid heat sources as much as possible;

②Design the hydraulic system correctly: For example, the system should have an unloading circuit, adopt high-efficiency hydraulic systems such as pressure adaptation, power adaptation, and accumulator to reduce high-pressure overflow loss and reduce system heat;

③Select hydraulic components correctly, strive to improve the processing precision and assembly accuracy of hydraulic components, and reduce leakage loss, volume loss and heat generation caused by mechanical loss;

④Correct piping: reduce the local pressure loss caused by too thin, too long, too much bending, improper branching and confluence;

⑤ Correctly select oil viscosity;

⑥ Sufficient heat dissipation area and tank capacity should be considered when designing the fuel tank. Generally, the capacity of the fuel tank should be selected at 2~6 times the pump flow rate (l/min). For systems with large flow rates, take the lower limit, otherwise the upper limit; for low-pressure systems, take the lower limit, and vice versa.

⑦When the floor space does not allow to increase the volume of the fuel tank or near the high temperature heat source, an oil cooler can be installed.

Roadheader For Mining

(2) Oil contamination in the oil tank of the roadheader for mining

The reasons for oil contamination in the tank are:

①There are paint stripping attendant sheets, welding slag stripping sheets, etc. in the fuel tank;

②The dust-proof measures of the fuel tank are not good, and the dust and corrosive gas have entered from the outside air;

③Due to the temperature difference, the water droplets condensed on the top cover of the fuel tank enter the oil cooler and break and cause water leakage.

Solution:

①The paint in the fuel tank should be compatible with the hydraulic oil. Pay attention to the paint process in the fuel tank. For example, the inner surface of the fuel tank should be painted after strictly removing the oil and rust.

②The fuel tank cover should be dust-proof and sealed. Only the air filter installed on the tank cover (often doubled as a fuel injection port) is allowed to communicate with the atmosphere to prevent dust in the air from being brought into the tank and used for air filtration on the same tank. The device has two functions: preventing large particles from mixing into the fuel tank during the refueling process and preventing dust from the air in the fuel tank when the system is working. Standard parts (EF type) have been sold;

③Check the leaking parts and remove them.