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Flow Meter

Trouble Shooting For Common Used Flow Meter

Flow meter is one of the mostly used instruments in industry. Only mastering the common handling measures of faults towards flow meter can we make a judgment to solve the problems coming cross in the process of production.

Common faults and its handling measures towards flow meter

1、positive—displacement flow meter

positive—displacement flow meter

roots flow meter



handling measures

the waist wheel does

not run

1、 The dirt blocks the pipes

2、The tested liquid is frozen

1、 To clean the pipe、filter and flow meter

2、 To resolve the liquid

The waist wheel runs

but the needles do not move or stop at times

1、The fork of gauge outfit is out of line

The dirt goes into the

speed charger of gauge

2、The needles or counter is jammed

3、The speed charger disjoints

To discharge the gauge outfit and to use hands to run the fork.If the instrument moves, it proves that the connection of gauge outfit and bearing is broken; if not, we have to check step by step.

Turning to sealed

coupling shaft with oil leakage

The gasket wears down

To tighten the gland or replace the gasket

The difference between the compensator and the small flow is partial

to be negative

The waist wheel collides with the shell, along with the abrasion of bearing or the immobilization to the main body of drive gear moves the position

To change the bearing and check the drive gear to see if the wheel body works; to fasten the

screw of gear to see whether it loosens or not

The error changes greatly

1、 The pulsing of liquid is rather big

2、 It contains gas

1、To reduce the pulsing

2、To add the getter device

oval gear flow meter



handling measures

Rotor does not rotate

1. The filter is blocked

2.The impurities enter into the flow meter, causing the rotor jams

1、To clean the filter
2、To check whether the filter is good or not and clean the interior of flow meter

Rotor runs normally

but the counter does not work

1、 Variable gear is meshing Badly

1. Each connecting part take off the riveting or the pin falls off

1、To demount the counters to inspect all or different levels of Speed chargers and counters

2、Do not make magnetic coupler bear over torque; otherwise it will produce the wrong poles and to degauss

Turning to sealed coupling shaft with oil


Sealed gasket wears down

To screw up the gland or change the gasket

Contact sealed

coupling shaft with


1、Glandloosens too much
2、Gasket wears down

To replace the sealed gasket and put some sealing oil into it

Indicated value is

smaller than actual


1、The flow excesses the regulated range

2、The viscosity of medium is relatively small

3、Some parts like rotor are rigid

1、To make flow to move within theregulated range or change the specification of flow meter

2、To re—mark the  standard, and to change as well as adjust the gear for the purpose of correction
3、To check the rotor、bearing and gear; to change the wearing parts

Indicated value is

bigger than actual


1、The flow pulses much
2、Some gases sneak into the medium

3、The viscosity of medium is rather big

1、 To reduce the pulsing of flow in the pipe
2、To install the degasser
3、To re—mark the  standard, and to change as well as adjust the gear for the purpose of correction

2、 Differential pressure type flow meter



handling measures

It indicates zero or has minimal


1、The balance valve is not close totally or leaks

2、The high and low pressure valves of the bottom in throttling gear do not open

3、The throttling valve is not accessible to differential pressure gauge valve and pipes

4、The steam guiding pipe is not whole cooling down

5、The liner between throttling valve and process pipe lacks sealing

6、Differential pressure gauge has internal fault

1、To close thebalance valve; to repair or renew it

2、To open the high and low pressure valve

3、To wash the line; to

repair or change the valve

3、 To open the instrument when it is totally cooling down

4、To screw up the bolt or replace the process pipe

5、To check and renovate

It indicates below


1、 The high and low voltage line reverse

2、Signal circuit reverses

3、High-pressure side line leaks or ruptures seriously


To inspect and access


3.To change the element or change the pipe

The indication is on the low side

1、High-pressure side line is lack of precision

2、Balance valve is not closed wholly or close tightly

3、The air of high-pressure side line is not emptying

4、Differential pressure gauge or secondary meter’s zero position lose balance or deflect

5、The throttling valve does not Match.The differential pressure gauge and discord with design requirements.

1. To examine、exclude and prevent leakage

2. To examine、close or repair

3. To free the air

4. To examine and adjust

5. To replace the matched differential pressure gauge

The indication is on the high side

1、 low-pressure side line is not precise

2、 High-pressure side line stores up gas

3、The pressure of steam is below the design value

1、Differential pressure gauge’s zero position moves

2、The throttling valve mismatches the differential pressure gauge

1、To check and exclude the leakage

2、To free the air

3、To amend according to the actual density

4、To check and adjust

5、To change the matched differential pressure gauge

The indication has

great fluctuation

1、The fluctuation of flow related parameter is too big

2、Pressure element is sensible to the fluctuation of parameter

1、To turn down the high and low pressure valve appropriately

2、To adjust the damping effect duly

The indicator does not move

1、Anti—freezing facilities are ineffective, resulting in the frozen of differential pressure gauge and the liquid in connecting pipe

2、The high and low pressure valve are not open

1、To strengthen the effect of anti—freezing facilities

3、 To open the high pressure valve

3. metal variable—area flow meter

metal variable—area flow meter



handling measures

The needles of

variable—area flow meter shake

1、The pulsing of medium

2、Unsteady pressure

1、To increased damping effect

2、To adopt stabile volt or vortex stabilizer

The needles stop at some position and do not move any


1、To open the valve too fast, causing the variable—area blocked

2、The variable—area‘s the guide rod is not aligned with its snap ring

1、To slow down the speed of opening the valve

2、To discharge the instrument and readjust

Large measurement error

1、The installation does not conform to the requirements

2、The density of liquid medium changes rather greatly

3、The temperature pressure has great effect

4、The pipe vibrates

1、To install with an angel that is not bigger than 20 degree vertically or horizontally

2、To calculate the error and amend the coefficient; to multiply the readings  and turn them into actual flow

3、Using warm pressure to compensate

4、To look for professional stuff to correct the positions of components

4. vortex flow meter

vortex flow meter



handling measures

It has no display when the flow

works normally

1、 Power line or fuse is broken or has bad contact

2、 The interior of display the device has bad contact

3、There is a disconnection of the coil

4、There is a fault in the channel of the sensor

1、To check with an ohmmeter

2、To take advantage of replacing“alternative” method

3、To check the coil is whether disconnecting or soldered dot loses wielding

4、To remove the foreign matter in the sensor and to clean or replace the damaged part

The display of

flow has been

gradually down

1、The filter is jammed

2、The spool from tabulation's valve of sensor is loose, reducing the valve opening

3、Impeller of the sensor is impeded by sundries

1、To clean the filter

2、To judge effectively if the spool losses through adjusting the valve wheel

3、To discharge the sensor and clean the sundries.It is necessary to check it again

The flow does

not move and the display of flow

does not turn to


1、 The transmission line shields and has an imperfect grounding

2、 The pipe vibrates, along with impeller shaking

3、The cut—off valve is not closed

4、The connection between a breadboard with another one of interior in display device or  electronic component deteriorates

1、To check if it is perfect grounding

2、To reinforce the pipeline or install a bracket in the front of or in the rear of the sensor

3、To check and repair or change the valve

4、To use“shortcircuit” method or inspect step by step to find out inference resource in order to detect the default point

Indicating value is largely different

From empirical

evaluation value

1、The internal passageway of the sensor breaks down

2、The backpressure of sensor is inadequate, appearing

air pockets and influencing the wheeling of the impeller

3、 Some reasons of the flowing in the pipe

4、 Something wrong happens

in the internal display device

5、Effectiveness for a given period of time for the materials that are permanent magnetism has loss of excitation in the detector

6、The actual flow in the sensor surpasses the prescribed limit

1-4.To figure out the reasons of default and  look for the solutions by aiming at the specific reasons

5、To replace the loss of magnetic cell

6、To change a proper sensor

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