In the high-pressure grouting construction, the cement slurry flow resistance is very big when the grouting is finished (usually 5MPa), the hydraulic system working pressure is very high, a lot of hydraulic oil flows back to the tank through the bypass, and the reversing valve is in 0 position. At this time, restart, there will be a motor, oil motor rotation, but the hydraulic cylinder does not move, “dead”. This is the result of the action of the equipment safety protection device. You must remove the plug wire located in the center of the end cover of the reversing valve, use the steel stick to move the heart of the valve, and then screw the plug wire, in order to operate normally. In actual construction, no matter whether it is slurry termination or pipe blocking accident, “dead” will occur.
The above operation is not only a waste of time and oil, but also inconvenient. So we tried to replace the blocking wire with the shut-off valve (valve switch) in the LPG pipeline. When “dead” occurs, turn the shut-off valve 90°, the small hole will be open, insert the reversing valve with No.8 wire (or copper welding rod) to reset the valve, pull out the wire and close the shut-off valve to resume work. This greatly simplifies the operation and facilitates the specific use.
When grouting is interrupted due to grouting termination or pipe blocking accident, in order to prevent deposition in the pump or in the high pressure hose, the slurry in the high pressure hose must be drained and the grouting pump and high pressure hose must be flushed with clean water.
The traditional method is to remove the high-pressure hose joint and empty it directly. Due to the high pressure of cement slurry in the high-pressure hose, the injection and hose flinging can easily cause injury accidents and also cause site pollution, which affects civilized construction.
According to the analysis, we believe that the emptying valve can better solve this problem, so in the high pressure slurry pump cement slurry outlet installed an additional tee with a shut-off valve, the need to hold the pipe emptying, open the tee on the shut-off valve (switch valve) for pressure relief, and then take off the hose, avoiding the various dangers of directly unloading the joint head, simplifying the operation.
The above-mentioned transformation was carried out at the site of the Post and Telecommunications Bureau, and the workers reflected well after the before-and-after comparison. The pile foundation task of the building undertaken adopted high-pressure grouting technology in the slope protection of the foundation pit, and the two valves played their proper role in the grouting construction. When dealing with accidents, it is easy to operate, saves time and effort, and the location of oil discharge slurry is clear and flexible to control, which ensures the hygiene of the site. This is in sharp contrast to the scene of other construction teams screwing and discharging indiscriminately during slurry injection. The equipment modification is not big, but the effect is obvious, which is praised by the owner and the supervisor.