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Oxygen Flow Meter
Jan 10, 2019

Oxygen flow meter

1 Brief

Oxygen flow meter,A flow meter used to measure the instantaneous and cumulative flow of fluids (liquids, gases, and vapors) through a closed conduit. It can indicate local and remote signal output.

The oxygen flow meter utilizes the dynamic action of the fluid to move the float upwardly in the vertically mounted measuring tube. The displacement of the float is proportional to the flow rate. Through the magnetic drive system, the float displacement is transmitted to the indicator in a non-contact manner to directly indicate the flow rate. It can also be equipped with a flow PCB board, output two-wire 4-20mA signal, HART protocol communication, low flow and high flow alarm.

Oxygen flow mete

2 Main feature:

Oxygen flow mete

◆ Stainless steel stamping and surface polishing;

◆ Mechanical pointer on-site flow indication, light and beautiful structure.

◆The explosion-proof local flow indicator and alarm switch combination are optional;

◆ Modular design, intrinsically safe + explosion-proof safety function, two-wire system 4-20mA\HART.

◆ The alarm switch optimization combination is optional.

Typical application:

Flow measurement and process control of liquid, gas and steam media in petroleum, chemical, metallurgy, electric power, food, pharmaceutical, paper and other industries.

3 Working principle

The oxygen flow meter is shown in Figure 2-1 and consists of a flow sensor and a flow indicator. The float is mounted vertically in the conical measuring tube and can float freely up and down in the conical tube due to the action of the fluid. A high-performance* magnet is embedded inside the float. As the float floats up and down, the magnetic field generated by the magnet changes. When the flow rate is stable and the float is in dynamic equilibrium, the magnetic field distribution around it is also fixed. Through the flow indicator mechanically connected to the cone measuring tube, the magnetic signal of the float can be transmitted in a non-contact manner, that is, the indicator can detect and process the flow value of the fluid by magnetic transfer. Finally, the flow rate is indicated by the pointer, indicated on the indicator's dial, and the LCD also reads the instantaneous and cumulative flow values, and outputs the standard two-wire 4-20 mA signal / HART protocol 2.1 gas measurement for gas flow measurement, When the valve is suddenly opened on the pipeline, or when the pressure is unstable, the flow of the flow will form a pulsating state, which will cause the float to move up and down in the measuring tube, and the pointer will also oscillate continuously, and the electrical signal will be output. Therefore, it is affected. As the floating signal of the float rises and falls, the system will not change and the system cannot be controlled and adjusted. To prevent this state from happening, a damping device is installed in the measuring tube as shown in Figure 2-2. The gas damping device is specially designed and manufactured by a CNC machining center to become a self-positioning anti-seize gas damping device. , Three-alumina ceramic material, which can reach a purity of 99.99%, has a long service life, corrosion resistance, novel structure, excellent practical performance, etc.


4 Basic parameters

Measuring medium: liquid, oxygen, steam,

Measuring range: (converted to standard medium, 100% value)

Water: 20 ° C (10-300000) L / h, special according to user requirements

Air: 0.1013MPa, 20°C (0.7-3000) m3/h, special according to user requirements

Range ratio: 10:1

Mechanical pointer indicates 1.5, 2.0, 2.5

Digital display (battery-powered, 2 years of use) 1.0, 1.5, 2.0, 2.5

Remote transmission type: simultaneous indicator indication, digital display (battery-powered, 2 years of use) 1.0, 1.5, 2.0, 2.5

Mechanical pointer indicates -80 ° C ~ +300 ° C, high temperature type 400 ° C

Digital display (battery-powered, 2 years of use) -40 ° C ~ +120 ° C, high temperature 400 ° C

Remote transmission type: simultaneous indicator indication, digital display (battery-powered, 2 years of use) -40°C~+120°C, high temperature type 400°C

Mechanical pointer indication -40 ° C ~ +120 ° C

Digital display (battery-powered, 2 years of use) -20 ° C ~ +60 ° C

Remote transmission type: simultaneous indicator indication, digital display (battery-powered, 2 years of use) -20°C~+60°C

Protection level: IP67

Nominal pressure:

DN15~DN50 Standard type: 1.6 MPa~4.0MPa (zui large DN15:42MPa, DN25:42MPa, DN50:32MPa)

DN65~DN250

Standard type: 1.6MPa (zui large DN 80:10MPa, DN100: 6.4MPa, DN125: 4.0MPa,

DN150: 4.0MPa, DN200: 2.5MPa, DN250: 2.5Mpa)

Process connection:

Flange connection, standard: DIN2501, ANSI, JIS (can choose Chinese standard, it is recommended to choose DIN first).

Sanitary clamps, threaded connection installation form when ordering.

Electrical connection M20×1.5 1/2"G 1/2"NPT 3/4"G 3/4"NPT

Installation method:

Vertical (downward and up), horizontal (horizontal pipeline; left to right, right to left), up and down (for vertical pipeline), lower side, side entry

Inlet straight pipe section ≥5D

Straight pipe section ≥250mm

Protection class IP67 (other instructions must be specified separately)

Explosion-proof mark:

Ex ia II CT5

Ex d II CT6

Intrinsically safe parameter: Ui=28V Ii=93mA Pi= 0.65W Ci≤ 5nF Li =0mH

Safety barrier parameters: Uo ≤ 28V Io ≤ 93mA Po ≤ 0.65W Co ≥ Ci + Cc Lo ≥ Li + Lc

5 Dimensions

Flange connection dimension drawing

Oxygen flow mete

Oxygen flow mete

Oxygen flow mete

Flange size

Oxygen flow mete

   


Caliber 

 Flange size (standard ANSI B 16.5 150 lb RF)

DN      

D

k

d3

f

n

d2

1/2"     

88.9

60.5

35.1

1.6

4

15.7

3/4"      

98.6

69.9

42.9

1.6

4

15.7

1"      

108.0

79.2

50.8

1.6

4

15.7

1-1/4"     

117.3

88.9

63.5

1.6

4

15.7

1-1/2"     

127.0

98.6

73.2 

1.6

4

15.7

2"     

152.4

120.7

91.9

1.6

4

19.1

2-1/2"    

177.8 

139.7 

104.6

1.6

4

19.1

3"      

190.5

152.4

127.0

1.6

4

19.1

4"   

228.6

190.5

157.2

1.6

8

19.1

5"      

254.0

215.9

185.7

1.6

8

22.4

6"      

279.4

241.3

215.9

1.6

8

22.4

8"    

342.9 

298.5 

269.7

1.6

8

22.4

10"    

406.4

362.0 

323.9

1.6

12

25.4



6.Process connection form, installation matters


6.1 Process Connection


Vertical form: as shown in Figure 6-1


When installing, ensure that the center perpendicular of the flowmeter and the vertical line are less than 2°.


The outlet and inlet of the oxygen flow meter shall be installed with a straight pipe section, and the straight pipe section shall be connected to the pipe diameter of the flowmeter.


Similarly, the flange or thread of the connection should match the flange or thread of the flowmeter.


Straight pipe requirements: L1 inlet straight pipe section: L1 = 5 × DN (5 times inlet diameter),


L2 outlet straight pipe section: L2 = 250 mm,


L3 magnetic filter: installation size see 6.2


Oxygen flow mete


Bottom side out form


As shown in Figure 6-2, the installation should ensure that the levelness and verticality are better than 1%. There are no special requirements for straight pipe sections.


Oxygen flow mete


Side entry side form


As shown in Figure 6-3, the installation should ensure that the levelness and verticality are better than 1%. There are no special requirements for straight pipe sections. There are no special requirements for straight pipe sections.


Oxygen flow mete


Horizontal form


As shown in Figure 6-4, the installation should ensure that the levelness and verticality are better than 1%. There are no special requirements for straight pipe sections.

Oxygen flow mete



6.2.1 Precautions before installation:


Oxygen flowmeters are precision instruments, so in the process of transportation, storage, installation and use, light rooms must be taken lightly to prevent barbaric transportation and over-stress installation. The overall position of the indicator and measuring tube must be guaranteed. Strict measurement, verification, and inspection are completed. Do not disassemble the indicator and measuring tube. If the indicator and measuring tube are disassembled at will, the measurement accuracy of the flowmeter will be affected. If the indicator and measuring tube need to be disassembled, the manufacturer must obtain it, or Under the guidance of the after-sales service personnel of the manufacturer, before installing the flowmeter to the process pipeline, disassemble all the inner packaging items, check the fillers required for transportation in the measuring tube, and whether there is any damage during transportation. When the flowmeter is installed, the process pipeline must be cleaned and 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. In order to prevent ferromagnetic particles and ferromagnetic impurities from adsorbing on the float in the pipeline, it is recommended to install a magnetic filter at the inlet of the flowmeter to prevent the float from getting stuck. The magnetic filter is shown in Figure 6-5:


Magnetic filter installation height dimension (length):


The flange standard is consistent with the flow meter, and the concave and convex sealing surface is selected; the flange sealing form is concave/lower convex.


(1) Installation height: 100mm


Caliber; DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100,


Pressure: PN1.6Mpa ~ 4.0MPa (4.0MPa does not contain DN80, DN100).


(2) Installation height: 120mm


Caliber; DN80, DN100


Pressure: PN2.5MPa~4.0MPa


(3) Installation height: 150mm


Caliber; DN125, DN150, DN200, DN250


Pressure: PN1.0MPa~2.5MPa


If the medium being measured is a gas, a valve should be installed at the outlet of the flow meter to allow the desired flow rate to be set. When the calibration pressure is maintained above the float, the gas will expand at the valve.


The instrument installed in the pipeline should not be subjected to stress. The outlet and inlet of the instrument should be supported by suitable pipes, which can make the instrument in a small stress state.


6.2.2 Precautions during installation


Since the measurement and conversion mechanism of the oxygen flowmeter adopts the form of magnetic transmission, the performance and accuracy of the flowmeter are ensured, and the surrounding environment of the flowmeter is within 200 mm, and iron and magnetic substances/items are not allowed to exist. Otherwise, the flowmeter will appear zero and not at zero, and the measurement will be biased. It can't be used when it is serious.


Special care should be taken when installing PTFE (polytetrafluoroethylene)-lined flowmeters. Even at low temperatures, PTFE will deform under the tightening pressure of the bolts. Therefore, the flange nuts must not be tightened at random. The way the angle of the conversion is gently tightened to avoid damage to the PTFE lining. When tightening, the large torque of the Zui Please refer to Table 6-1. When installing the pipe, do not have snowboard and iron and magnetic materials to wrap the flowmeter. If there is a parcel, the flowmeter will move at zero. Zero, the measurement is biased. It can't be used when it is serious.

Oxygen flow meter

6.2.3 Opening for the first time


Liquid measurement: In order to avoid sudden opening of the valve, forming a head impact and damaging the instrument during the process of opening the valve, it is necessary to open the valve slowly!


Gas measurement: Do not pressurize the pipe before opening the valve. Otherwise, if the valve (eg solenoid valve) is suddenly opened, the float will rush to the upper limit and may damage the instrument, so it is necessary to open the valve slowly.


The instrument for measuring gas can be equipped with a pneumatic damping device to reduce the fluctuation of the float to a large extent. To further ensure the stability of the float, a throttle or suitable orifice plate can be installed at the outlet of the meter.


For smart and HART type indicators, first ensure that the electrical wiring is correct and that power is not applied until the check is correct. Please refer to the operating instructions for the adjustment of the program.