『How to Clean Flow Meter: Flush the piping with a compatible chemical solvent or use soft brushes to clear deposits from internal linings.』Related information(v cone flow meter|rotary gas meter|gallon meter|gear meter|metal tube rotameter|glass tube rotameter|nutating disk meter|transit time ultrasonic flow meter|wedge flow meter|pd meters|hydraulic flow meter|ultrasonic water flow meter|water flow meter|air flow meter|magnetic water flow meter|oxygen flow meter|gas flow meter|argon flow meter|air velocity meter|gasoline flow meter|fuel flow meter|ultrasonic water meter|digital water meter|nitrogen flow meter|solid flow meter|Oxygen tank flow meter|digital water flow meter|diesel fuel flow meter|steam flow meter|02 flow meter|compressed air flow meter|oil flow meter|liquid flow meter)
How to Clean Flow Meter: Flush the Piping with a Compatible Solvent or Use Soft Brushes
Quick Answer: Flush the piping with a compatible chemical solvent or use soft brushes to clear deposits from internal linings. Match the cleaner to the liner material and deposit type. Do not use metal brushes on any liner. Send your fluid type, pressure, temperature, pipe size, and deposit type to Silver Automation Instruments for a model specific procedure.
Cleaning a flow meter is simple if you check the wetted parts first. We have seen operators damage a PTFE liner with a metal scraper. Small scratches can shift the 4-20 mA output on an electromagnetic flow meter.
Here is the thing. Solvent flushing does most of the work. Manual brushing is only the second step. Most engineers skip the chemical compatibility check and then damage EPDM liners with solvent. In practice, a 5 percent citric acid solution at 40 degree Celsius handles scale in water and wastewater meters. For oil and grease, use isopropyl alcohol or a warm detergent solution.
Step 1: Isolate and Inspect
Depressurize the line before removing any flow meter. Use lockout tagout procedures. Check the flange rating and process condition. For a DN80 electromagnetic flow meter in a water treatment plant, close the isolation valves before pulling the meter. Look at the deposit before choosing a cleaner. Black iron oxide from steel pipe is not the same as white calcium scale. A customer in Vietnam had a DN50 magnetic flow meter with brown manganese deposits from groundwater. A citric acid flush restored the reading within one shift.
Step 2: Chemical Solvent Flush
Flush the piping with a compatible chemical solvent. Start at a low flow rate. Do not exceed the meter maximum velocity. For a DN40 Coriolis meter, start at 1 m/s and stay below 10 bar line pressure. A small diaphragm pump works better than a centrifugal pump because it gives controlled flow.
The solvent depends on the liner and deposit. PTFE and PFA liners tolerate most acids, alkalis, and solvents below their temperature limits. EPDM is limited to mild acids and alkalis. For water scale, use 5 percent citric acid. For oil and grease, use isopropyl alcohol or warm detergent solution. For food and beverage meters, use 1 percent sodium hydroxide at 70 degree Celsius and then a clean water rinse. Check the outlet pH before returning the meter to service. Hard deposits may need 30 to 60 minutes of circulation. A 45 minute citric acid flush removed lime slurry scale that a quick 10 minute rinse did not touch.
Step 3: Soft Brush Cleaning
Use soft nylon brushes to clear deposits from internal linings. Do not use wire brushes or metal scrapers. For a vortex flow meter bluff body, use a bottle brush without a metal core. For an oval gear flow meter, remove the cover and use a soft brush on the gears. Soak the gears first if the oil has turned into varnish.
A paint manufacturer in Southeast Asia cleaned an oval gear meter with a brass brush. The meter lost 12 percent accuracy on a 200 cP resin because the gear clearance changed. Silver Automation Instruments replaced the gear set.
Thermal mass flow meters are different. Do not brush the sensor elements. Use compressed air below 2 bar to blow loose dust off the probes. For oil film, remove the probe and clean with isopropyl alcohol on a soft cloth.
Magnetic Flow Meter Electrode Cleaning
Electromagnetic flow meter electrodes are sensitive. Do not use abrasive pads. For calcium scale, dip a cotton swab in diluted acetic acid an
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A desalination plant in Oman had a DN100 electromagnetic flow meter with seawater scale on the electrodes. A soft brush with 5 percent citric acid cleaned the electrode surface and the 4-20 mA signal stabilized.
Cleaning by Process Industry
In oil and gas, wax deposits can block a turbine or oval gear meter. Flush with diesel or kerosene at low velocity then purge with nitrogen. In water and wastewater, iron and manganese deposits respond well to citric acid or oxalic acid. In food and beverage, clean-in-place systems handle flow meters daily. Use hot caustic at 80 degree Celsius and then an acid rinse. In marine service, ultrasonic flow meter transducers collect marine growth. Clean the transducer face with a soft cloth and water. Do not scratch the coupling surface.
What Not to Do
Do not use a metal brush on any flow meter liner. Do not use high pressure air on an assembled positive displacement meter. Do not use solvent that swells polyurethane liners. Check the chemical compatibility chart first. Do not exceed the liner temperature rating. EPDM typically handles up to 120 degree Celsius. PTFE handles up to 150 degree Celsius. At high temperature, the liner softens. Do not remove a flow meter from a pressurized line without isolation. ATEX Zone 1 installations need extra care with static discharge.
Contact Silver Automation Instruments
If the meter reading does not return to normal after cleaning, check the zero point and flow calibration. Some meters need a new liner or gear set. Silver Automation Instruments supplies electromagnetic flow meters, Coriolis mass flow meters, ultrasonic flow meters, vortex flow meters, oval gear flow meters, and thermal mass flow meters.
Send us your fluid type, flow range, pipe size, pressure, temperature, and deposit type. We will provide a step by step cleaning procedure for your meter model. Contact Tel: +86-25-68650347. WhatsApp: +86-25-52155837. WeChat: +86 15365082610. Send your pressure in bar, temperature in degree Celsius, pipe size in DN, and flow range in kg/h or m3/h.
Frequently Asked Questions
Can I clean a magnetic flow meter without removing it from the pipe?
Yes, if the meter has clean-in-place ports or if the process piping allows a chemical flush. Isolate the meter, flush with a compatible solution, and rinse. For heavy scale, remove the meter and use a soft brush.
What solvent is safe for a PTFE liner flow meter?
Most acids, alkalis, and solvents are safe for PTFE below 150 degree Celsius. For water scale, use 5 percent citric acid at 40 degree Celsius. Avoid molten alkali metals and some fluorine compounds.
Can I use a metal brush to clean an oval gear flow meter?
No. Metal brushes change the gear profile and the clearance. Use a soft nylon brush after soaking. If deposits are hard, replace the gears instead.
How often should process flow meters be cleaned?
It depends on the service. In lime slurry or heavy crude oil service, clean every 1 to 3 months. In clean water service, a yearly inspection is enough. Use pressure drop changes or signal drift to set a schedule.
Does Silver Automation Instruments provide cleaning procedures for its flow meters?
Yes. We send a procedure based on your meter model, liner material, fluid type, and process conditions. Contact us by Tel or WhatsApp and include your pipe size and flow range.
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