Suspended hydraulic props are used as supporting equipment in coal mines, and underground mines are relatively dangerous places. Suspension hydraulic props is a kind of external injection type hydraulic props. During liquid injection, the three-purpose valve does not rise with the rise of the movable prop , which is convenient to operate, safe and reliable. Below we mainly explain the cavity-free oil hydraulic pressure of the single hydraulic props. Let's follow the China Coal Group editor to take a look.
The hydraulic double-acting prop is based on the original DZ-type hydraulic prop, and an additional injection valve is added to the body part of the handle. When injecting liquid into the three-way valve, the leg raises the leg and moves the frame. Suspension type monolithic piston adopts a high-sealing performance sealing device, which not only increases the width of the seal line, but also directly introduces the working fluid into the seal ring, and uses its automatic compensation to produce a sealing effect that is completely different from the traditional hydraulic prop. The sealing performance is good. long lasting. Large lifting force. For soft floor with low compressive strength, it can be equipped with a large base with ironing function-iron shoes.
Suspension monolithic cylinder adopts copper plating, and the living cylinder adopts galvanized nickel alloy and high corrosion-resistant passivation process. In theory, when pressure oil enters the rodless cavity of the cylinder, a thrust F is formed on the piston, so that the piston has a tendency to move to the cavity with a rod. The hydraulic prop for mining is shut off because the oil cylinder has a rod cavity to return the oil, and the oil in the cavity quickly forms a back pressure, which causes the two ends of the piston to be balanced and stand still. At this time, F has = F is not, and the pressure of the cavity-free oil is different due to the different bearing area of the piston, that is, P is> P is not. In the practice of a single hydraulic prop, as the two chambers of the oil cylinder form a gap to communicate, the pressure oil in the oil chamber cavity tends to flow from the high pressure area to the low pressure area. As soon as the flow occurs, the pressure P in the cavity decreases, and P does not increase. If the thrust F at both ends of the piston is not> F, the piston loses its balance and moves to a cavity with a rod to find a new equilibrium point. This reciprocation will stop the piston until it is blocked by external force.
Because it is an internal leak, the miner cannot detect it with the naked eye, so the internal leak is an uncontrollable safety hazard, which has caused a lot of roof accidents. The working fluid uses an emulsion; the DWH prop cylinders and live cylinders use zinc-nickel alloy plating technology. The working fluid can directly use medium-sized water, which can eliminate pollution to groundwater and is environmentally friendly. At the same time, the company's newly developed floating disk and double floating type monomers have made certain breakthroughs in strengthening the support of soft floors and avoiding the phenomenon of column breakage caused by the increase of roof pressure. The domestic advanced EDA anti-corrosion technology has been adopted to double the surface anti-corrosion capacity of the living cylinder.
Inspecting all suspension monolithic control elements, especially the speed control elements, found no problems. Some of the speed control valves were replaced, and the fault has not been eliminated. Later, after disassembling the oil cylinder, it was found that the piston "O" seal was severely worn, which caused the hydraulic oil in the two chambers of the oil cylinder to channel each other. Analyze the reason. After the "O" seal is worn, the gap between the rod cavity and the rodless cavity of the oil cylinder increases. When the speed regulating valve 3 or the shut-off valve 2 is closed, the oil return path of the rod cavity of the oil cylinder is cut. .
