During high-pressure grouting construction, at the end of grouting, the flow resistance of cement slurry is very high (usually 5MPa), and the working pressure of the hydraulic system is very high. A large amount of hydraulic oil flows back to the oil tank through the bypass, with the reversing valve in the 0 position. At this time, when restarting, the motor and oil motor will rotate, but the hydraulic cylinder will not move, resulting in a “crash”. This is the result of the action of the equipment safety protection device. The plug wire located in the center of the reversing valve end cover must be removed, the valve core moved with a steel bar, and then the plug wire tightened to allow normal operation. In actual construction, whether grouting termination or pipe plugging accidents occur, there will be a “crash”.
The above operations are not only a waste of time and oil, but also inconvenient. Therefore, we tried to replace the blocked wire with the stop valve (valve switch) in the liquefied gas pipeline. In the event of a “crash”, rotate the stop valve core by 90 °, and the small hole is unblocked. Insert 8 # iron wire (or copper welding rod) into the reversing valve to reset the valve core, pull out the iron wire, and close the stop valve to resume operation. This greatly simplifies operation and facilitates specific use.
When grouting is interrupted due to grouting termination or pipe plugging accidents, in order to prevent deposition in the pump or high-pressure hose, it is necessary to drain the slurry in the high-pressure hose and flush the grouting pump and high-pressure hose with clean water.
The traditional method is to remove the high-pressure rubber hose connector and directly empty it. Due to the high pressure of cement slurry in high-pressure rubber pipes, spraying and swinging of rubber pipes are prone to injury accidents, which also cause site pollution and affect civilized construction.
According to the analysis, we believe that the evacuation valve can better solve this problem, so a tee with a shut-off valve is installed at the cement slurry outlet of the high-pressure grouting pump. When the pipe needs to be evacuated due to choking, open the shut-off valve on the tee to relieve pressure, and then remove the rubber pipe, avoiding various dangers of directly unloading the joint, simplifying the operation.
The above transformation was carried out on the construction site, and the workers’ feedback was good after comparison. In the pile foundation task undertaken, high-pressure grouting technology was used in the foundation pit slope protection, and two types of valves played their due role in the grouting construction. When handling accidents, it is easy to operate, saves time and effort, has a clear location for oil and slurry drainage, and has flexible control, ensuring site hygiene. This is in sharp contrast to the scene of other construction teams randomly screwing and arranging grout in a first-class manner. The equipment has not been changed much, but the effect is obvious, which has been praised by the owner and supervisor.
Post time: Apr-03-2023