1. Selection of installation environment
(1) stay away from equipment with strong phenol water field, such as large motor, large transformer, etc.;
(2) there should be no strong vibration in the installation site, the pipes should be firmly fixed, and the ambient temperature should not change much;
(3) the installation environment shall be easy to install and maintain.
2. Selection of installation location
(1) the installation position must ensure that the pipeline is always filled with the measured flow;
(2) choose the place where the fluid flow pulse is small, that is, it should be far away from the pump, valve, elbow and other local resistance;
(3) when measuring two-phase (solid, liquid or gas, liquid) fluid, the place which is not easy to cause phase separation should be selected;
(4) negative pressure should be avoided at the measuring site;
(5) it is easy to measure the diameter or circumference of the pipeline and the ellipticity should be small.
3. Requirements for direct pipe segment
The length of the straight pipe section on the upstream side of the sensor installation pipeline shall be greater than or equal to 10D, and the length of the downstream side shall be no less than 5D (D stands for the measured pipe diameter).
4. Flow control valve and regulating valve
The flow control valve shall be installed on the pipeline under test on the upstream side of the sensor, and the flow control valve shall be installed on the downstream side of the sensor. When measuring, the flow control valve shall normally be in a fully open state.
5. Installation of sensors
(1) the sensor shall be installed vertically with the measuring pipe (see FIG. 1). When the sensor is inserted into the pipe, the included Angle with the vertical diameter of the pipe section shall be less than 5°.The sensor insertion point has two methods: one is inserted into the central axis of the pipeline under test (that is, 1/2 of the pipe diameter);Two is inserted into the pipe wall is 1/4 of the pipe.
(2) turn off the upstream flow control valve or use low pressure water supply.
(3) install DN50 ball valve to the seat, pay attention to the ball valve long cavity up, check whether the ball valve can be fully open, fully closed, if there is a problem can be repaired.Install the compacting screw base, the compacting nut and the rubber seal ring on the ball valve, loosen the positioning screw and the compacting nut, and insert the sensor insert rod into the pipeline under test through the ball valve.The insertion depth is calculated from 6.4.4 and measured by a vernier caliper or a steel tape measure. After meeting the requirements, tighten the nuts and positioning screws. Meanwhile, it should be noted that the direction of the sensor marker rod should be pointed in accordance with the flow direction of the fluid.
(4) use a vernier caliper or a steel tape measure to measure the distance between the sensor electrode and the direction marker bar. Suppose the length of the sensor electrode and the direction marker bar measured is H.For D < 400 mm diameter, E=H-0.121D
6. Welding of mounting base
(1) the axis of the installed base pipe is perpendicular to the axis of the pipeline under test;
(2) the conventional stainless steel flange is welded flat with stainless steel electrode, and the PVC pipe can be welded with hot melt adhesive strip. After welding, the flange end face shall be parallel to the pipe axis, the weld shall be firm, and the flange can withstand 1.6mpa without leakage.
(3) the hole size of the pipeline under test is the same as the size of the mounting base.
The flow signal generated by the sensor is very weak, usually in microvolts or millivolts.Therefore, preventing the influence of external electrical interference is an important factor to use the flow meter well, and grounding is a very effective measure to solve the influence of electrical interference.