2. Installation requirements for connecting pipelines horizontally installed sensors require that the pipelines should not have an inclination that can be perceived by naked eyes (generally within 5), and the verticality deviation of vertically installed sensor pipelines should also be less than 5. Where continuous operation is required and the flow cannot be stopped, a bypass pipe and a reliable stop valve should be installed to ensure that the bypass pipe has no leakage during measurement. Insert a short pipe to replace the sensor at the position where the sensor is installed in the newly laid pipeline. After the "line sweeping" work is completed and the pipeline is confirmed to be clean, formally connect the sensor. Because this work is neglected, it is not uncommon for the sensor to be damaged by scanning line. If the fluid contains impurities, a filter should be installed on the upstream side of the sensor. If the flow cannot be stopped, two sets of filters should be installed in parallel to remove impurities in turn, or the filters should be automatically cleaned. If the measured liquid contains gas, a getter should be installed on the upstream side of the sensor. The sewage outlets and degasifiers of filters and degasifiers should lead to a safe place. If the sensor is installed at the low point of the pipeline, in order to prevent the impurities in the fluid from settling and staying, a discharge valve should be installed in the pipeline behind it to discharge the settled impurities regularly. The flow regulating valve should be installed downstream of the sensor, and the cut-off valve on the upstream side should be fully opened when measuring. These valves should not vibrate and leak outward. Check valves should be added in the process of possible backflow to prevent fluid backflow. The sensor should be concentric with the pipeline, the gasket should not extend into the pipeline, and the liquid sensor should not be installed at the highest point of the horizontal pipeline, so as to avoid the gas accumulated in the pipeline (such as mixed air when the flow is stopped) staying at the sensor, which is not easy to discharge and image measurement. The front and rear pipelines of the sensor should be firmly supported without vibration, and thermal insulation measures should be taken for the sensor of easy-to-condense fluid and its front and rear pipelines.
3. In order to open and close the flow sensor without bypass pipe, first open the upstream valve of the flow sensor with a moderate opening, then slowly open the downstream valve and run for a period of time with a small flow (for example, 10 minute), then fully open the upstream valve, and then open the large and small downstream valves to adjust the required normal flow.
For the flow sensor equipped with bypass pipe, first fully open the bypass pipe valve, moderately open the upstream valve, slowly open the downstream valve, and turn down the opening of the bypass valve, so that the instrument can run at a small flow rate for a period of time, then fully open the upstream valve and fully close the bypass valve (to ensure no leakage), and finally adjust the opening of the downstream valve to the required flow rate.
4. Start-up of low-temperature and high-temperature fluids Before the low-temperature fluid pipeline flows through the pipeline, the water in the pipeline should be drained first. When flowing through it, it should run at a small flow rate of 15 minutes, and then gradually increase to normal flow rate. Do it slowly when stopping the flow, so that the temperature of the pipeline and the ambient temperature are gradually close, and the operation of high temperature fluid is similar.