Turbine gas meter

LWQZ Model





Professional In Systems Analysis

THECO turbine gas meter is a precision measuring instrument which has high accuracy and good reliability. It can measure all kinds of single-phase gas and be widely applied to measure gas in oil, chemical industry ,metallurgy. electricity power and combustion gas in cities,

  • High precision, good repeatability and wide measuring scale ratio, to 1:20 (or wider)
  • equipping integrative two-stage rectifier, the length of straight pipe requirement is larger than 2 times of nominal diameter before the flow meter and larger than nominal diameter behind the flow meter.
  • Wall-connected reaction structure and distinctive sealing structure are to make sure the reliability of the bearing working long time,
  • Using two kind of bearings, self-lubricating and stainless-teel oiling according to users demanding.
  • The technical parameter complies with 1S09951. the length of the instrument’s case is 3 times of nominal diameter and the performance of the whole is advanced in the world,
  • The intelligent volume corrector of the flow meter could be turned 340 free and the users can read it expedientig under various installations.
  • Detect the temperature, pressure and flow rate of the medium and automatically calculate the flow rate compensation and compression factor adjustment by integrating high precision temperature, pressure, accurate flow sensor and intelligent volume corrector.
  • Possess real time database, form network by telephone line using RS-485 communication interface or special MODEM made in our factory, which is very convenient for centralized data sampling and real time management.
  • Compact structure, strong anti-interference ability and high reliability of the circuit board by using surface mounting technology.
  • Employs high performance MCU and the modern digital filtration technology embedded powerful and superior performance software.
  • Floating calculation and five segment coefficients for self-correcting and with automatically detecting troublesome and alarming functions.
  • Very low power consumption and operating with inner battery or external power by using advanced micro- power consumption technology.
  • Display flow rate on the pot and attached multi-outputting functions.
  • Several measurement values such as standard volume accumulation, standard volume flow rate, volume rate percentage under operating condition, medium temperature, pressure and power capacity percentage of battery, can be
displayed directly on a high contrast three-lined LCD with Europeian character indicatooe

.Real time data storage function prevents data from loss when power disappears or exchange battery, all instrumental parameters can be kept permanently.
  • Possess explosion-proof function; the explosion-proof grades are ExdIIBT4 and ExiaIIBT4
  • The defend grades are IP54 (explosion-proof type) and IP65 (securiy type)

3.1 Principle of the turbine flow meter

The fluid is rectified and accelerated in the deflector ahead (or the flow conditioner)when it enters the meter. Because turbine vanes make an angle with the fluid,the turbine begin to swirl after it overcome rub moment and fluid obstruction moment. The angular frecquency is proportional to the volume flow rate within a certain scope of fluid velocities. The pulse signal is derived from the coil terminals of the magneto-sensor according to the principle of electro magnetic induction; the frequency of signal is proportional to the fluid volume flow rate. Th signal is delivered to the smart volume corrector after having been amplified, filtered and shaped, Then the pulse signal

together with temperature signal and pressure signal are displayed on the LCD screen after signals processing computed by the corrector. The Structure and principle is shown in picture .1.

Figure 1. Structure schematic of the turbine gas meter

3.2 Principle of the smart volume corrector

The intelligent volume corrector include analogue signal channel of temperature and pressure, digital signal channel of flow rate, microprocessor unit, driver circuit of Liquid crystal Display (LCD), interface of the output signals and other auxiliary circuit. Figure 2 shows the principle of operation. Multi-channel signals from sensors are transformed and sent to the microprocessor to calculate according to the gas equation. The results can he displayed locally or transmitted to remote hosts.

Gas equation is defined as follows:


Vo—Volume under standard conditions (m3 )

V—Volume under operation conditions (m3)

P=Pa+Pg—Absolute pressure of the medium at the pressure detecting point (kPa)

Pa- Local atmosphere pressure (kPa)

Pg- Meter pressure of the flow meter at the measure point (kPa)

Po- Standard atmosphere pressure (101.325 kPa)

To-Absolute temperature under standard conditions        (293.15K to be changed to 273. 15k,if necessary)

T- Absolute temperature of the medium (273.15+t) K

t- Temperature of the medium (C)

Fz= (Zn/Zg)1/2—gas compression factor, for nature gas,  it is calculated using the formula in SY/T6143 standard made by oil and nature gas Coporation.

Zn—gas compression factor under standard conditions.

Zg—gas compression factor under operating conditions.

Fig.2 Principle diagram of the intelligent volume corrector

  1. Technical specifications
4.1 standard

The technical specifications of LWQZ-Ill intelligent gas turbine flow meter comply with 1S09951 and the flow meter is made according to the enterprise standard of Q/ZCY-06-2003 "LWQZ-II1 intelligent gas turbine flow meter".

4.2 precision grade

Using the high repeatability of the turbine flow rate sensor can correct five segment coefficients of the instrument, and then the precision grade in the scale is 1 grade and 1.5 grade. Without correcting five segment coefficients, the precision grade is according to  the ISO9951 international standard.

1 grade:0.2Qmax- -Qmax: ± 1%; Qmin —O.2Qmax 2%

1.5 grade:0.2Qmax - Qmax: ± 1.5%: Qmin- ---O.2Qmax: ± 3%

4.3 Electrical specifications

4.3.1 Power supply
  • Inner power supply: 3.6 VDC, lithium battery. Real-time display capacity percentage of the battery in the screen to remind user's to change battery.
  • External power supply: (6~24)VDC, rippling voltage50 mv. When the external power supply is connected, the inner battery is automatically disconnected immediately, and the flow meter is powered by the external power supply.
4.3.2 Power consumption
  • Inner power supply: the total average power consumption0.8mw, When meter is active, a piece of 2" Lithium battery can continuously work more than two years. The power consumption 0.2mw, When meter is sleeping.
  • External power supply: total power consumption 1W.
4.3.3 Input signals
  • Flow rate signal: (0~5) KHz pulse signal Vpp=2.5V
  • Temperature signal: Resistant signal from temperature sensor.
  • Pressure signal: Voltage signal (mV) from pressure sensor.
4.3.4 Output signals
  • Pulse signal (three-wire configuration): outputs the amplified pulse signal that is directly from the flow rate sensor, the maximum amplitude is about (Vo-2)V ,(Vo is 6VDC ~24VDC of externd suplly),the transportation distance50m.Operating with external power.
  • (4-20)mA standard analog signal; (4—20) mA is linear corresponding to (0~ Qmax) m3/h (standard flow rate signal), the range is determined by setting instrument parameters FL and FH. Transportation distance 200m, connection is two-wire or three-wire configuration, power supply is+24VDC external power supply.
  • Standard flow tate signal: outputs pulses in serial mode (output of OC gate at the open’s circuit, Vo<I6VDC electric source), the normal state is low, transportation distance 20m. Pattern 1;the pulse period is 5ms; each pulse stands for 0.1 m3 standard volume. Pattern 2; the pulse’s width of high electrical level is 1 each pulse stands for 1m3 standard volume and equipped two-stage insufficient voltage alarming output of the inner battery. when the battery voltage is below 3.2 volt, VL2’s output is high and when the battery voltage is below 3.1 volt, VL1’s output is high: when the battery voltage is above 3.2 valt,the outputs of VL1 and VL2 are low. It is suitable to control system with IC card.
  • RS-485 communication signal: It can be used to directly connect to remote host computers and to transmit the data of temperature, pressure, instantaneous flow rate, standard volume accumulation of the medium and the meter’s parameters, malfunction codes, operation
states real time data, etc. The flow meter can communicate with the host through telephone network when it works together with the special MODEM that can support eight flow meters at most.
  • ReaI time database: To fit the requirement of data management, the function of real time data storage is carefully designed. The data include:
  1. a) 400 points of start/stop time of the meter and the corresponded data of accumulation recently;
  2. b) Accumulation recorders at fixed time of recent 48 months;
  3. c) 360 recent state records (including time, temperature, pressure, instantaneous flow rate and accumulation). The record interval can be set to from I to 9999 min.
The stored data can be read by a notebook PC or a table PC through RS-485 interface, and can be displayed in reports or graphs that would he very helpful in analysis work.
  • Telephone network communication and management software; When the meter works together with the special modem using telephone line to transmit data, the software can read historical data, malfunction state and instrument parameters of any remote flow meter linked to the phone net. The telephone communication management software could get the perfect auto-management function according to user’s demanding.
4.4. Mechanical specifications

4.4.1 Table 1: Type Basic parameters

4.4.2 Typical characteristic curve

Figure 3 shows the typical charactristic curve of the flow meter. Y coordinate axis stands for basic error of the flow meter, X coordinate axis is percentage of the maximum flow rate of the flow meter.

Fig 3. Typical characteristic curve

4.4.3 Pressure loss of the flow meter

The pressure loss relates to the turbin's running, the friction in the pipe, The speed and director of the 1iquid. Pressure lose  can be calculated by the following formula under the operating conditions:


- pressure loss of the biggest flow rate under standard conditions ,when         the medium is dry air(20C,101.325 Kpa, ρ=1.205) , see table 1

— medium density under standard conditions

Pa —local atmospheric pressure(kPa)

Pg —pressure of the flow meter at the measuring point (kPa).

Po — standarst atmospheric pressure 101 .325kPa)

To- absolute temperature under standard conditions (293.15K, and it can be changed to 273.15K if necessary)

Tg- absolate temperature of the medium under operating conditions (273, 15+1)K

Q- flow rate under operating conditions ()

Qmax- the biggest flow rate under operating condition's (m3/h)

5.Outline dimensions and installation

5.1 Outline dimensions

Outline dimensions of the flow meter are shown in Figure 4, no marking dimensions in the Figure 4 are Listed in Table 2. The flow meter are connected with flanges; flange size complies with the standard of GB/T9112~9113-2000.

Figure 4. Outline dimension diagram of the turbine flow meter

5.2 Installation
  • lnspect the ambient operating conditions with the meters requirements before installation; avoid external strong magnetic jamming and strong, mechanical oscillation near the flow meter, in order to ensure the flow meter work properly.

  • in applicably to operate the meter under the conditions of flow rate’s changing is frequent and pulsating flow is high or pressure pulsation exists.
  • Flow meter must be installed horizontal, the fluid direction must be same as direction mark on the meter. strainght pipe with the length of 2DN and I DN should be reserved upstream and downstream of the installed flow meter respectively.
  • •Install a corresponding specification filter (provided by factory) at the distance larger dam 2DN ahead of flow meter
  • Flexible pipe and bellows should be considered to install when install the meter and measure pipes. Laying pipes upstream and ci downstream of the flow meter according to its actual dimension to make meter’s strains minimal that caused by the pipes’ strains
  • flow meter should be installed with the same central axis of the pipe, and prevent seal gasket and butter into the pipe.
  • Flow meter must connect with the ground of reliably, please do not use the ground of high electric voltage system. Please do not connect
the ground of melting system with that of the flow meter when install or maintain pipes.

  • User is not allowed to arbitrary change the connecting mode of the explosion—proof system and the interface of leading wires. Any changes should comply with relative requirements in the standard of’ GB3836.1-2.
  • Slowly open valve, gradually increase flow rate, when starting meter to prevent instantaneous gas shock from damaging turbine vanest (Opening time 15s).
  • External supply ( 24 VDC) should be connected complying with the Electric specifications strictly when the measurement signal needs remote transmission. Inhibit from connecting power supply (220VAC or 380VAC) to measurement signal output terminals.
  • lnhibit from electric melding flanges at inlet or outlet of the flow meter directly in case damaging components of the flow meter during installation, Take down the instrument to avoid damaging the measurer seriously during cleaning the pipes and doing the static pressure experiment of all the liquid
  • Flow meter cannot be installed until all sundries it pipe are removed by blowing pipe when it is first used or just finished maintenance.
  • Please take care of the pressure tolerant rating of the flow meter when processing leakage test after installation, in case damaging the pressure sensor.
  1. Operation and installation
6.1 Ambient conditions
  1. a) Ambient temperature: -~+
  2. b) Relative humidity: 5% ~ 95%.
  3. c) Atmosphere pressure: 86kPa~106kPa

6.2 Flow conditions
  1. a) Range of the flow temperature: -~+
  2. b) The flow how should be no swirling single—phase flow (include air), without sundries stich as grandles and fibre.
  3. c) Range of the flow temperature and pressure should be within the specifications of the flow meter 6.3 Operating methods
6.3.1 Displaying mode of set parameters

Each input parameter is displayed on 10 digits LCD by pressing keys. The definition indictor and format arc listed in Table 3.


Double passwords of the flow meter can prevent from changing instrumental parameters hostility and affecting measuring accuracy.

each password has its privilege of modifying correlation parameters. The password must be confirmed before modifying parameters. Parameters can be modified only passing the confirmation, A digit will flashes at an interval of 1 second if it is allowed to change. Password confirmation

Press the set key (K1) till the password state displayed, then press the number key (K3) and the shift key (K2) in order Set digits according to the c correspondent original password one by one from the right side to the left side. Finally press the set key (K1) to confirm. Set parameters

After the password is confirmed properly, the parameters are ready to be set or modified Press the set key (K1) till modifying or setting state, then press the number key (K3) and the shift key (K2) in order. Set digits one by one from the right side to the left side. After setting appropriate values, press the key K1 to confirm the operation. After all parameters are set press the reset key (K4) to return to setting slats and the flow meter will return to initial operation stats (After operation of modifying or setting parameter, the flow meter will return to initial operation stat automatically if reset key is not pressed and no other keys are pressed within 2 minutes).

Warning: To avoid  impairment of the precision of the meter and normal operation of the meter, users are not allowed to change at will the parameters behind the factory password (PP)which have been already properly when the meter leaves factory.

6.4 Connection wire method

6.4.1 External power supply of intelligent valum corrector and connection wire are showed in figure 6. The definitions and functions of the connectors are as follows:

EX-V- Positive pole of external power supply

GND- Negative pole of inner and external power supply

PULSE- Pulse signal output under operation state;

FOUT- Pulse signal output under standard state;

Io+-Output positive terminal in two or three- wire configuration

Io- -Output negative terminal in two- wire configuration

VL1, VL2- Output alarming signal under insufficient voltage.

A, B- RS- 485 communication connecting terminals.


The markers of the external power supply and the signal below output are on the back shell of meters, The connections of the inner sensors have been already finished before the meter leaves factory. Please do not change them arbitrarily. You can connect them according to figure 6 and markers of the battery box if necessary.

Figure 6 external power supply and output Connection
of the intelligent volume corrector

6.4.2 system connections The connections of the system showed in figure 7.

(a) 4mA— 20mA output, two- wire connection diagram

(b) 4Ma-20Ma output, three- wire connection diagram

(c) pulse signal output at working condition, three- wire connection diagram

(d) Pulse signal output standard condition, three- wire connection diagram

(e) RS- 485 communication output connection diagram

(f) alarming signal under insufficient  voltage(duoble circuit)

Figure 7. The system connection diagram of the flow meter

6.5 Application notes for (4~ 20)mA standard analog signal output

6.5.1 two- Wire configuration

The relationship between output voltage of (4~20)mA current circuit and the maximum resistant value of external load is as follows:


The load resistance RL550. The relationship between supply voltage and external load resistance refers to Figure 8. The load resistance should be selected within the operating range.

Figure 8. The relationship between supply voltage and external load resistance

6.5.2 three- wire configuration

The relationship between output voltage of (4~20)mA current circuit and the maximum resistant value at external load is as follows:

RL(max)= (Vs-2)/20mA=(24-2)V/20mA= 1100

The load resistance RL1100. The relationship between supply voltage and external load resistance refers to Figure 8. The load resistance should be selected within the operating range.

6.6 Application for inner battery

6.6.1 Battery capacity indicator

The trend value of battery electric quantity is displayed as percentage (%). the displayed value 40% indicates that user should pay attention to the inner battery, when 20% appears. the inner battery should be replaced within a month.

6.6.2 Method for replacing battery

Open the behind cover. put off two screws, open the battery proof cover, take out old battery, put into a new one (2"3.6V lithium battery) according to the polarity tag on the proof cover, use hand to press the proof cover without any looseness, then put on two screws tightly, fix the battery proof cover. At last close the behind cover.

6.7 numerical reading

6.7.1 Meter and count the flow rate directly because the measure parameters are displayed in the LCD screen of the smart volume corrector.

6.7.2 the one-off instrument of the meter and the volume corrcctor are connected by the special structure so that it could turn the smart volume corrector  free to count easily when the meter is limited by the installation ambient to influence normal counting.

7.lubrication and maintenance

7.1 lubricating system

7.1.1 the self-lubricating bearing and the stainless-steal bearing

To satisfy the user’s different demanding, our factory use two kind of bearings (self-lubricating and stainless- steal) in the LWQZ-III gas smart turbine flow meter. The self-lubricating bearing is used easily and needs no many mending, it can he used to measure the cleanin, dry and non-erodent medium. The stainless- steel bearing needs to be oiled by definite quantity in time to make sure the instrument’s good lasting usage.

7.1.2 Oiling system

The stainless-steel bearing needs oiling by definite quantity in time to make its working performance's best. So LWQZ-lll gas intelligent turbine flow meter is equipped with special oiling installation system when the bearing is stainless steel. The oiling installation is equipped on the basis of the turbine flow meter’s DN, As shown in figure 9.

Figure 9 the Special oil installation equipped in the turbine flow meter

The oiling frequency is based on the operating conditions and the measured mediums when oil the stainless- steel bearing and usually oil 3-4 times one year. The demanding oiling quantity at one time of the different DN turbine flow meter is shown in table 4

NOTE: the stainless-steel bearing needs oiling by definite quantity in time, not too much or little to avoid influencing the measuring accuracy of the flow meter.

7.2 Safety and reliability

To get the expected accuracy and normal working life, the turbine flow meter should operate in the allowance flow rate range and under the authorized running conditions. Overspeed turning of the turbine and the solid in the pipes could make the flow meter attrite and damage ahead of time. So selecting proper specifications, correct installation and suitable operation and maintenance could make sure the instrument run normally.

7.2.1 Filter

Because the impurity and scrape in the pipes could short the turhine flow meter working life, when the impurity in the measured mediums is bigger than 5Oum, must install the filter and monitor the pressure difference between the beginning and end in the filter to change or clean the filter’s core in time and make sure the filter work in good conditions to avoid flowing distortion.

7.2.2 overload

The flow rate pulsation usually appears and is high sometimes because the pressure pulses in the pipes under the operation of the turbine flow meter. LWQZ-III is designed on the basis of the maximum flow rate authorized by the 1SO 9951. The instrument wouldn't damage when the time of the overloading 120%Qmax is shorter than 30 minutes. Suggest install the flow snubber in the lower reaches of the instrument to make sure the flow rate overloading is below 120%Qmax under high pressure condition.

7.3 ability of anti-interference

The well-connected integrative two-stage rectifier equipped in the LWQZ-III intelligent gas turbine flow meter has been detected under the low and high interference conditions authorized by the 1SO 9951, the length of straight pipe requirement is larger than 2 times of nominal diameter before the flow meter and larger than nominal diameter behind the flow meter. As shown in figure 10.

Figure 10 the allowance installation of the turbine flow meter

  1. Package, transportation and storage
8.1 How meter should be put into a fastness wooden box (the meter that has middle or small diameter is used with foam and paper box), the meter should be motionless in box. The box should be conveyed with caution, not to he pushiness loading and unloading

8.2 Transportation and storage of the flow meter should fit the requirements in JB/T9392- 1999 (Basic environments and test methods for transportation and storage of instruments).

8.3 Storage of the flow meter should meet the following conditions:
  1. a) Avoiding rain and humidily
  2. b) Avoiding mechanical vibration and shock
  3. c) Temperature range: C~ C
  4. d) Relative humidity: not higher than90%
  5. e) No erosive gas in environment
  6. Unpacking and checking
9.1 Check whether the external easing is intact before unpacking, then the integrity of component quantity and type according to the packing list.

9.2 Documents and materiel.
  1. a) Packing list
  2. b) Instruction manual
  3. c) Product certificate ol appraisal.
  4. d) Product certificate of quality.
  5. e) Information feedback bill of using the product
  6. f) special oil (not equipping in the self-lubricating bearing system)
  7. Ordermg information
10.1 When order the product, user should select suitable type according to operating pressure, the highest pressure, temperature, flow rate range. of the measured medium kind and environment conditions and select proper electric gauge on the basis of practice.

10.2 The flow meter is normally field-displaying type. Demanding must be written into the ordering bill when other output functions are required.

10.3 example selecting

Known the actual working pressure is 1MPa~1.5MPa (pressure ot the gauge) the temperature range of the medium is -~+, the quantity of conveyed gas is (4000~9500)Nm3.h.Demanging: definte the flow meter’s DN.

Analyzing: the range of flow rate is given under the operating conditions, so must convert the flow rate under the standard conditions to the operation conditions, then select proper DN.

Calculating: when the medium’s pressure is the lowest and temperature is the highest (don’t consider the influence of the nature gas compression factor when estimate the type), then when air feed is at the peak the volume flow rate is maximum, so.

Similar, when the medium’s pressure is the lowest and temperature is the highest, then when air feed is at the valley, the volume flow rate is minimal,so

Then the flow rate range of the medium St operation conditions is (227.2~ 9337)m3/h. Look up table 1 and then select DNI50

If need a intelligent gas turbine flow meter with outputs of standard flow rate signal, pulse signal and RS-485 communication interface signal , equipped oil pump and with accuracy grade is 1.5,(4~20)mA output with three wire mode , wire length is 100m, the specification should be filled as follows:

10.4 Please fill information as following when order

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