Concrete piston automatic returning device in closed type pumping system

Abstract

The invention relates to a concrete piston automatic returning device in a closed type pumping system. The closed type pumping system comprises at least two groups of main oil cylinders (6 and 6') with rodless cavities (601 and 601') and with-rod cavities (602 and 602') and an oil tank (T). Concrete pistons (8 and 10) are arranged at one ends of piston rods (501 and 501') in the with-rod cavities (602 and 602'). Preset oil pressure exists in the with-rod cavities (602 and 602'). The concrete piston automatic returning device comprises a first control valve arranged between the rodless cavities (601 and 601') and the oil tank (T). When the first control valve is in an open state, the rodless cavities (601 and 601') are communicated with the oil tank (T), the preset oil pressure in the with-rod cavities (602 and 602') pushes main oil cylinder pistons (5 and 5') to press the rodless cavities (601 and 601'), and the concrete pistons (8 and 10) are driven to contract back. The concrete pistons in the closed type pumping system can return automatically, and changing convenience is brought to an operator.

Description

technical field [0001] The invention relates to a closed pumping technology, in particular to an automatic return device for a concrete piston in a closed pumping system. Background technique [0002] Concrete pump truck is a kind of construction machinery for engineering construction that uses pressure to continuously transport concrete through pipelines. In the mechanical pumping system of the concrete pump truck, the concrete piston is a vulnerable part, which needs to be checked, cleaned and replaced frequently. Greater loss. [0003] Because the concrete piston is in the concrete cylinder during work, the concrete piston must be retreated from the concrete cylinder into the water tank before disassembly when replacing. Therefore, it is necessary to frequently retreat the concrete piston from the concrete cylinder into the water tank during use and maintenance, to check the wear condition of the concrete piston or to replace the concrete piston. It can be seen that wh...

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Problems solved by technology

[0011] It is the existence of this pressure that makes the concrete piston 8 return to the water tank 7, and during the power cut-off process, due to the gradual decrease in the speed of the main oil pump 2 and the power cut-off, the pressure at the working oil ports A and B of the main pump drops rapidly. After the pressure in the rod chamber 602 decreases, due to the existence of the pressure in the rodless chamber 601, the piston rod 501 of the main oil cylinder will be pushed out, which will cause the position of the concrete piston 8 to drift, making it more difficult to replace the concrete piston 8, and even failure to take it out. Condition of the concrete discharge piston 8

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