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Installation Tips For The Orifice Flow Meter

Aug 15, 2019

Ten precautions before installation of orifice flowmeter

1. Before the instrument is installed, the process pipeline should be purged to prevent the ferromagnetic substances retained in the pipeline from adhering to the instrument, affecting the performance of the instrument and even damaging the instrument. If it is unavoidable, a magnetic filter should be installed at the entrance of the meter. The meter itself does not participate in the air sweep before the production, so as not to damage the meter.

2. The instrument should be inspected for damage before it is installed in the process piping.

3. The installation form of the instrument is divided into vertical installation and horizontal installation. If it is vertical installation, the angle between the center vertical line and the vertical line of the instrument should be less than 2°; if it is horizontal installation, the horizontal center line of the instrument should be the horizontal line angle is less than 2°.

4. The upstream and downstream pipelines of the instrument shall be the same as the diameter of the instrument. The connecting flange or thread shall be matched with the flange and thread of the instrument. The length of the straight pipe upstream of the instrument shall be at least 5 times the nominal diameter of the instrument, and the length of the downstream straight pipe segment shall be greater than equal to 250mm.

5. Since the instrument transmits signals through magnetic coupling, in order to ensure the performance of the instrument, at least 250px around the installation, no ferromagnetic substances are allowed.


6. The instrument for measuring gas is calibrated at a specific pressure. If the gas is directly discharged to the atmosphere at the outlet of the meter, a pressure drop will occur at the float and cause data distortion. If this is the case, install a valve at the outlet of the meter.

7. The instrument installed in the pipeline should not be subjected to stress. The inlet and outlet of the instrument should have appropriate pipe support to keep the instrument under minimum stress.

8. be especially careful when installing PTFE (polytetrafluoroethylene)-lined instruments. Since the PTFE will deform under the action of pressure, the flange nut should not be over tightened at will.

9. The instrument with liquid crystal display should avoid direct sunlight when installing, and reduce the service life of the liquid crystal.

10. When measuring low temperature media, you need to select the jacket type.


Twenty-eight precautions in the installation process of orifice flowmeter

1. The opening of the meter should avoid opening holes in the forming pipe.

2. Pay attention to the length of the straight pipe before and after the flowmeter.

3. If there are electromagnetic, quality and other flowmeters with grounding requirements, grounding should be carried out according to the instructions.

4. When the process pipeline is welded, the grounding wire should avoid the instrument body to prevent the grounding current from flowing into the ground through the instrument body and damage the instrument.

5. When welding the process, avoid the grounding current flowing through the capillary pressure guiding tube of the single and double flanged instruments.

6. The medium and high pressure impulse pipe can be argon arc welding or socket welding, and argon arc welding or socket welding should be adopted. Wind speed > 2m / s, there should be wind-proof measures, otherwise the coating wire should be used, wind speed > 8m / s, must have wind-proof measures, otherwise the welding should be stopped.

7. Pay attention to the installation direction of the flow port of the flowmeter throttling device.

8. Stainless steel pressure pipe is strictly prohibited; it is strictly prohibited to flatten the pressure pipe.

9. The installation position of the instrument's impulse piping, air duct and threading pipe should avoid the process production operation in the future, should avoid the high temperature corrosion place, and should be fixed firmly; the lowest lead end of the threading pipe from the upper side should be lower than the lower lead end The wiring inlet end of the connected instrument; the lowest end of the threading pipe should be added with a drip tee; the Y-type or tapered explosion-proof sealing joint should be added near the instrument side; the lowest point of the main wind line of the instrument should be a condensing (soil) valve.

10. The copper gasket used in the instrument, if not annealed, should be annealed before use, and pay attention to the allowable temperature, medium and pressure of various material gaskets.

Leaf dividing line

11. In the field instrument junction box, the grounding of different grounding systems cannot be mixed. The shielding wires of all instruments should be connected separately to the upper and lower shielding layers. It is forbidden to screw them together to connect the upper and lower shielding.

12. When the instrument is in an unobservable and inspected position, change the position or install the platform.

13. The joint is forbidden in the middle of the instrument line, and the hidden record is made. The compensation wire joint should be welded or crimped.

14. Stainless steel welds should be pickled, passivated, and neutralized.


15. Instruments and fittings that need to be degreased should be degreased in strict accordance with the specifications, and the sealing and storage of the instruments and fittings after degreasing should be carried out to prevent secondary pollution during storage and installation.

16. Stainless steel pipelines are strictly prohibited from direct contact with carbon steel.

17. Galvanized and aluminum alloy cable trays are strictly prohibited from being cut and opened by electricity, gas welding, and similar mechanical cutting and opening should be used without tooth saws and special hole openers.

18. Stainless steel pipes are strictly prohibited from being cut and opened by electricity or gas welding. Plasma or mechanical cutting or opening should be used.

19. Instrument threading pipes, cabinets, discs, etc. larger than 36V should be grounded, grounding instrument threading pipe threading wire should be treated with conductive paste; instrument threading pipe thread buckle of 36V or less should have at least anti-rust treatment; exposed thread buckle should not be larger than one wire buckle.

20. Instrument Threading Pipes in Explosive Hazardous Areas shall maintain electrical continuity.

21.100 volts are measured using a 250V shaker to measure the line insulation resistance and ≥ 5 MΩ.

22. The aluminum alloy bridge should be short-circuited across the short-circuit. The galvanized bridge should be tightened with not less than two anti-loose screws. The length should be reliably grounded within 30 meters. If it exceeds 30 meters, a grounding point should be added every 30 meters.

23. When the instrumentation line of different grounding systems shares a slot with the power supply line, they are separated by a metal partition.

24. It is strictly forbidden to use the gas welding method in the installation and processing of the instrument panel, cabinet, box, and table. The welding method should not be used for installation and fixing. The mechanical opening method should be adopted for the opening.

25. The blind end of the instrument for heating and returning water should not exceed 100mm.

26. The lower part of the transmitter drain valve should be equipped with a cap that prevents leakage of the valve (especially in the explosion-proof area).

27. The instrument and its threading pipe and pressure pipe are fixed at one end in the thermal expansion zone (such as the tower, the accessory moving with the thermal expansion of the tower), and one end is fixed in the non-thermal expansion zone (such as labor protection room). When connecting the instrument, it should be based on the actual situation on site. The flexible pipe, the threading pipe and the pressure pipe must have a certain thermal expansion margin.

28. The tower bridge and the threading pipe shall be provided with thermal expansion joints or flexible connections according to the actual situation on site.