Research And Application Of A High Stability Driving Device In New-type Differential Pressure Densimeter

Based on principle of density measurement by differential pressure method, through investigating the problems of common differential pressure densimeter arising in site operating and theoretical analysis of them and then research of experiments, draw a conclusion that slurry flow rate and the stability of dynamic pressure imposed on the pressure sensor of the measurement container is the key problem. Develop a high stability driving device make sure that all kinds of water cement ratio slurry go through the measurement container at a constant velocity. Developed a diversion valve which can be used in cement slurry at low velocity, high-density state and realize that all kinds of water cement ratio slurry overflow along the top export edge of the measurement container. Specific research ideas and contents are as follows:Consider of differential pressure densimeter installed in the grout pipe, effected by frequent regulator and changes of plasma absorption volume in the irrigation formation, the slurry flow rate in the measuring tube is transient, resulting in transient dynamic pressure imposed on the pressure sensor of the measurement container which is even more than the pressure of the slurry. However, the regulation and control of pressure in grouting and plasma absorption in the irrigation formation are basic operations and conventional response, which is an insurmountable technical problems of the common differential densimeter. The most feasible approach is to remove the densimeter out of the grouting pipeline and provide it with a high stability driving device to complete the slurry density testing.Choose the sewage pump which can pump cement slurry and transform its core components-reducing the impeller diameter, to ensure a head tube match with the height of the measurement container. Equip the pump with common three-phase asynchronous motors and make use of the mechanical hard features of this motor-speed of the three-phase asynchronous motor keep constant when the load changes, to ensure that speed of the pump is almost constant. To ensure the safe operation of the motor, put to use the double mechanical seal technology at the shaft between the motor and pump, protecting the test motor and pump from the slurry with an effective separation.Improved the abnormity three-way pipe,30°angle diversion, making sure a minimum flow pressure loss and a reasonable distribution of the slurry, to ensure all kinds of water cement ratio slurry flow through the measurement container. Also developed the no-ventileinheit wedging transmutable volume control valve, no-ventileinheit solving the problem interference of slurry state by overcurrent element, moving of the wedge slide in the valve chamber solving the control of flow volume,45°slant section of the wedge ensuring the stability of the flowing slurry state. Through the adjustment of the valve, ensure all kinds of water cement ratio slurry overflow along the top export edge of the measurement container further.