Magnetic Flow Meter Installation
Tue, Oct 04 by ATO.com
Usually, the magnetic flow meter housing protection is extremely IP67 and has the following requirements for the installation site. Let's follow ATO to learn more about it.
Installation Site Specifications
- When measuring mixed-phase fluids, pick a location that won't lead to phase separation; when measuring two-component liquids, stay away from installing in the downstream of an uneven mix; when measuring chemical reaction pipelines, install them in the downstream of the reaction's fully finished section.
- As much as possible, prevent the measurement tube from going into negative pressure.
- Choose a location with minimal vibration, particularly for one-piece instruments.
- Keep large transformers, motors, and other electrical equipment away from the area to prevent electromagnetic field interference.
- It is simple to identify the location where each meter is grounded separately.
- Steer clear of any environment that has a lot of corrosive gas concentrations.
- Ambient temperature must not exceed -25/-10 to 50/600 °C; a body-shaped structure's temperature must not exceed this range because it contains electronic components, which have a smaller temperature range.
- Do your best to stay out of the sun.
Installation requirements for straight pipe sections
- Firstly, take note that the flow meter itself cannot be utilized as a load support point; instead, a clamp must be applied to the load-bearing pipe next to it. The magnetic flow meter upstream also needs a specific length of the straight pipe section to acquire a normal measurement degree, but its length is shorter than that of the majority of other flow meters.
- To prevent the butterfly valve flange from entering the meter measuring tube, use a 90o elbow, T-shaped pipe, concentric reducer, fully open gate valve after the meter that is 5 times the diameter of the flange connection surface from the inlet end (5D) length of the straight pipe section, and a downstream straight pipe section for (2–3) D. The upstream and downstream straight pipe length standards or calibration techniques are also inconsistent, with some electromagnetic flowmeter requirements that are higher than the typical high requirements. This is to guarantee that the current 0.5 level of instrument accuracy criteria are met.
Installation position and flow direction
- There are no constraints on the meter installation directions, which can be horizontal, vertical, or inclined (fluid must flow in a horizontal or inclined upward direction). Nonetheless, to guarantee that the processing pipeline and the measurement tube are coaxial. Axis deviation shouldn't be more than 2MM. Bottom-up flow, good vertical installation, measuring solid-liquid two-phase fluid.
- This can prevent solid phase precipitation at low flow rates as well as the drawbacks of horizontal installation when the lower portion of the lining is locally significantly deteriorated.
- In order to protect the lining of the flow meter next to a pipeline from heat and to ensure that the instrumentation converter signal line is not connected, it must be installed horizontally with the electrode axis parallel to the horizon rather than perpendicular to it because the top electrode is more likely to have liquid on it and the electrode in the ground to be covered by sediment.
Installation of the negative pressure pipe system
- Negative pressure pipe systems must carefully apply a fluorine plastic lining meter; positive pressure pipe systems should be prevented from producing a negative pressure, such as when a liquid system's temperature is higher than room temperature; in this case, shut off the meter's upstream and downstream shut-off valves to stop operation;
- The meter should be installed close to the negative pressure prevention valve.
- Separate grounding of the flow meter is required (10 ohms or less grounding resistance). In theory, the flow meter side should have a separate grounding, and the converter grounding should be at the same grounding point. If the meter is installed in a cathodic corrosion protection pipeline, it should be grounded along with the grounding ring and thicker copper wire (16mm) installed on the two connecting flanges of the pipeline to isolate the cathodic protection current from the meter.
- When the stray current becomes excessive, like when the leakage current from the electrolytic tank along with the electrolyte influences the normal measurement of EMF, the flow meter can be removed and connected to the electrical isolation process. The pipeline has cathodic protection, which can also be used; cathodic protection current impacts EMF measurement.