General principles for electromagnetic flowmeter selection
(1) Whether the medium to be tested is a conductive liquid or slurry, thereby determining whether an electromagnetic flow meter is selected;
(2) The conductivity of the measured medium determines the type of electromagnetic flowmeter—whether it is high conductivity or low conductivity;
(3) The nominal diameter of the large, small and common flow process pipelines required by the process, determine whether the flow rate of the medium is at a more economical flow point, whether the pipeline needs to be reduced, and then determine the diameter of the flowmeter;
(4) Determine whether to use an integrated or split flowmeter, and the degree of protection of the flowmeter, etc., based on the layout of the process piping.
(5) Selecting the electrode type according to whether the measured medium is easy to crystallize or crusting;
(6) selecting an electrode material according to the corrosiveness of the measured medium;
(7) The corrosiveness, wear and temperature of the measured medium determine the lining material to be used;
(8) The high working pressure of the measured medium determines the nominal pressure of the flow meter;
(9) The insulation of the process piping determines the type of grounding ring.
Electrode material
Corrosion resistance and wear resistance
Stainless steel: 0Crl8Nil2M02Ti is used for industrial water, domestic water, sewage and other weakly corrosive media. It is suitable for petroleum, chemical, steel and other industrial sectors as well as municipal, environmental protection and other fields.
Hastelloy B: has good corrosion resistance to hydrochloric acid at all concentrations below the boiling point, and is also resistant to corrosion by non-chlorinated acids, bases, non-oxidizing salts such as sulfuric acid, phosphoric acid, hydrofluoric acid, and organic acids.
Hastelloy C: resistant to non-oxidizing acids, such as nitric acid, mixed acid, or corrosion of mixed media of chromic acid and sulfuric acid, and also resistant to oxidizing salts such as Fe, ", Cu" or other oxidants, such as Corrosion of hypochlorite solution and seawater above normal temperature
Titanium: It is resistant to seawater, various chlorides and hypochlorites, oxidizing acids (including fuming sulfuric acid), organic acids and alkalis. It is not resistant to the corrosion of relatively pure reducing acids (such as sulfuric acid or hydrochloric acid), but if the acid contains an oxidizing agent (such as nitric acid, Fc++, Cu++), the corrosion is greatly reduced.
钽: Excellent corrosion resistance and glass are very similar. In addition to hydrofluoric acid, fuming sulfuric acid, alkali, it is almost resistant to the corrosion of chemical media (including boiling point of hydrochloric acid, nitric acid and sulfuric acid below 50 ° C). Antimony in alkali; corrosion resistant.
Platinum/titanium alloy
Almost resistant - cut chemical media, but not for aqua regia and ammonium salts.
Stainless steel coated tungsten carbide
For non-corrosive, strong abrasive media.
Note: Due to the wide variety of media, its corrosiveness is affected by complex factors such as temperature, concentration and flow rate, so this table is for reference only. The user should make his own choice according to the actual situation. If necessary, the corrosion resistance test of the material to be selected, such as the coupon test.
Third, gas turbine flowmeter daily inspection
1. Look at the display: Observe the total amount, instantaneous, temperature, pressure, and battery power. If the abnormality is reported in time.
2. Listen to the running sound of the flowmeter. (Method) The flowmeter should have no noise when it is running normally. If there is a large abnormal noise, it can be judged as damage to the movement of the movement (for example). It needs to be reported and processed in time.
3, data comparison, the output of the first 3 to 5 days before the statistics, if there is no major change, the flowmeter runs normally, such as the successive decrement phenomenon, the gas turbine flowmeter impeller (shaft, shaft core), filtration There is a problem with the device. Need to be reported in time for processing
4, gas turbine flowmeter filling lubricant
(1) Instrument refueling is an important part of the daily maintenance work of the instrument. Lubricating oil is mainly for instrument bearing; lubricating oil can protect the instrument bearing, reduce friction, reduce wear and prolong the operation cycle of the instrument;
(2) Regularly adding lubricating oil can effectively reduce the maintenance rate of the instrument and reduce the maintenance cost;
(3) Ensure the measurement accuracy of the flowmeter. "Measuring is counting money." why would you said this? The management of production and operation accounting, energy saving, cost accounting, etc. is an important production link of enterprise management. If the measurement is not in place, it will affect the economic efficiency and reputation of the enterprise. Therefore, the daily maintenance of the instrument is very important.