Manual
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0. List of contents
1. Design and Function
1.1. Description
1.2. Function
1.3. Meter sizes
1.4. Dimensions
1.5. Construction
1.5.1. Main housing
1.5.2. Measuring cartridge
1.5.3. Counter head
1.5.4. Flow conditioner
1.6. Materials
1.7. Measurement and pulse outputs
1.7.1. Counter head
1.7.2. NF-Reed-Contacts
1.7.3. NF-NAMUR-Pulse sensors
1.7.4. HF-NAMUR-Pulse sensors
1.7.4.1. HF1 and HF2
1.7.4.2. HF3
1.7.5. Link specification of the electrical pulse sensors
1.7.5.1. Pulse sensors in the counter head
1.7.5.2. Pulse sensors in the meter body
1.7.5.3. Technical data of the Reed-Contacts
1.7.5.4. Technical data of the NAMUR-Pulse sensors
1.7.6. Pressure measurement
1.8. Designation and signs
2. Measuring values
3. Measuring accuracy
3.1. Error of the measurement principle
3.2. Error of the installation
4. Pressure loss
5. Transport and storage
6. Installation
7. Putting into operation
8. Maintenance
9. Seals
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1. Design and Function
1.1. Description
The industrial quantometer CPT serve for the volume measurement of flowing gases. They
were developed by the company COMMON in close co-operation with the oil and gas
industry. The standard version is appropriate for the gases in table 1 for pressure rates up to
20 bar. The operating pressure amounts to thus 0 to pmax the appropriate pressure rate of the
meter.
Table 1.
List of appropriate gases for the measurement with industrial quantometers in standard
version
Gas
Argon
Ethylene
Butan
Ethan
Natural gas
Helium
Carbon dioxide
Carbon monoxide
Air
Methan
Propane
Nitrogen
Hydrogen
Symbol
(chemical
formula)
Ar
C2H4
C4H10
C2H6
He
CO2
CO
CH4
C3H8
N2
H2
Density ρn*
[kg/m³]
Density
relating to air
1,78
1,26
2,71
1,36
~0,83
0,18
1,97
1,25
1,29
0,72
2,01
1,25
0,09
1,38
0,98
2,09
1,06
~0,64
0,14
1,53
0,97
1,00
0,55
1,56
0,97
0,07
*(ρn at 1,01325 bar and 273,15 K)
The gas meters are specified by the following parameters:
Nominal size DN, maximal operating pressure pmax, as well as maximum flow Qmax and
minimum flow Qmin under operating pressure and operating temperature.
The admissible error between Qmax and Qmin under operating conditions is designed according
to the margins of error of turbine gas meters as per EEC guideline for volume gas meters. The
minimum flow results from the calibration of the meter.
1.2. Function
The measurement principle of the quantometer is based on the proportionality of the linear
gas rate for the rotating speed of the turbine wheel in the defined annular space of the
measuring cartridge. This area of the gas meter was designed according to the laws of the
mechanical measuring technique of liquids and gases. Counter sums up the passed gas volume
and brings it to the display.
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1.3. Meter sizes
The standard sizes of the COMMON industrial quantometers are arranged in table 2.
Table 2.
Standard sizes of the industrial quantometers CPT
DN
mm
G-Size
maximum
flow Qmax
minimum
flow Qmin
40
65
100
160
250
160
250
400
400
650
1000
[m³/h]
65
100
160
250
400
250
400
650
650
1000
1600
[m³/h]
6
10
8
13
20
13
20
32
32
50
80
inch
50
2
80
3
100
4
150
6
Measure NF1 – NF4
ment
Counter head
range
pulse rate Ua m³/Imp.
1:10
0,1
1:20
1
1:20
1
1:20
1
10
1.4. Dimensions
figure 1:
External dimensions of the industrial quantometer CPT
HF1 – HF2
Counter head
m³/Imp.
HF3
Turbine wheel
m³/Imp.
1,84929E-04
3,69858E-04
9,24645E-04
1,18519E-03
2,12954E-03
7,22932E-04
1,44586E-03
2,58587E-03
2,58587E-03
4,57365E-03
7,75761E-03
6,10862E-06
1,01810E-05
2,34947E-05
3,26246E-05
5,86196E-05
3,40498E-05
5,95871E-05
1,06569E-04
1,06569E-04
1,50792E-04
2,55766E-04
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The external dimensions of the industrial quantometers can you take from the table 3. An
allocation of the parameters takes place according to the figure 1. The dimensions are to be
considered when planning from measuring systems.
Table 3.
Dimensions and weights of the industrial quantometer CPT
DN
mm
50
80
100
150
inch
2
3
4
6
Pressure rate
PN10/16
ANSI150
A
mm
100
120
150
180
B
mm
65
80
100
127
C
mm
18
21
29
50
D
mm
32
38
53
76
E
mm
140
150
165
190
F
mm
65
77
91
116
G
mm
199
211
225
243
H
mm
252
278
305
351
Weight
kg
3,6
5,3
7,4
11,6
1.5. Construction
The industrial quantometer consists of 4 main components:
Figure 2:
Sectional view of the industrial quantometers CPT
1.5.1. Main housing
The main housing is manufactured from extruded aluminium.
The dimensions and weights of the meters are indicated in table 3.
The housing of the meter owns no flanges. The installation of the meter will be done between
DIN or ANSI flanges the pipe installation, by using of long bolt screws. For detecting of the
operating pressure at the meter, is at the front side one pr - connecting piece in form of a
tapped hole M 12 x 1,5 available.
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1.5.2.Measuring cartridge
The measuring cartridge contains the turbine wheel, which is hold by self lubricated ball
bearings on the main shaft. The rotating motion of the main shaft will be reduced by gear
wheels and transferred to the magnetic coupling.
A direct detecting of the rotating motion of the turbine wheel as high frequency impulse is
additionally possible by the optional installation of one HF sensor.
1.5.3. Counter head
The transfer of the angular momentum from the main housing loaded by pressure into the
counter head is made by a gas tight magnetic coupling. In the counter heading a further
reduction of the rotating speed of the waves is made by snail and gear wheels up to the drive
of the 8-digit roll counter. A gear set is to be implemented changeable to realise an adjustment
of the roll counter.
To pick up electrical impulses is given a possibility by up to two HF Namur sensors, up to
two NF Namur sensors and up to two NF Reed contacts. As standard, each counter is
equipped with one NF Reed contact. The electrical connection, to take the impulses from the
counter head can take place over up to two sockets, whereby one socket is installed as
standard. The output signals of the HF sensors in the counter operate adjustmentindependently proportionally to the optionally HF sensor on the turbine wheel of the meter.
1.5.4.
Flow conditioner
The quantometer has an integrated flow conditioner on the upstream site. To fulfil the
requirements for the stated accuracy of the meter in the gas installation, a straight and
undisturbed upstream pipe of minimal 5 x DN in front of the meter has to be planned.
1.6. Materials
All by the construction of the industrial quantometers CPT used materials guarantee the
necessary stability and corrosion resistance. The meters are material-technically checked
before distribution. Appropriate certificates in accordance with DIN EN 10204 can be
requested.
The meter bodies are manufactured from aluminium. They are galvanised and outside coated
with varnish paint.
The integrated flow conditioner is manufactured from plastic.
The turbine wheel, the measuring cartridge, the meter body, as well as the oil pump are
manufactured from aluminium alloys.
Moved parts like shafts, snails or bearings consist of stainless steel.
Gear and snail wheels are manufactured from plastic.
The transparent parts like counter displays consist of polycarbonates.
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1.7. Measurement and pulse outputs
Figure 3:
Measurement outputs of the industrial quantometer CPT
1.7.1. Counter head
The mechanical 8-digit roll counter head is the main counter of the industrial quantometer
CPT. It displays the passed gas volume at operating pressure and operating temperature.
Depending of the meter size, the display value corresponds to the lowest place 0.01 m³ up to
1 m³. The counter head is rotatable around 345°, so that it is configurable into almost all
directions, in order to ensure a good readability in all installations.
1.7.2. NF-Reed-Contact
In the counter head Reed-Contacts (NF1 and NF2) are available depending upon execution up
to two, whereby one Reed-Contact NF1 is equipped as standard. They are adjusted like the
mechanical roll counter and output pulses, which are in direct relation to the mechanical
display. This type of contacts is electric potential free and has a high long-term reliability.
Mostly by Reed-Contacts battery powered devices are connected such as volume correctors or
tariff devices. You find a representation of the position as well as the connection possibilities
in the figures 6 and 7, as well as the specification of the pulse values in table 2. The technical
data please take from the paragraph: „Technical data of the Reed-Contacts“.
1.7.3. NF-NAMUR-Pulse sensor
NF-NAMUR pulse generators are optionally possible up to two slot initiators (NF3 and NF4)
in the counter head They are adjusted like the mechanical roll counter and the Reed-Contacts
and output pulses, which are in direct relation to the mechanical display. The use of such
active pulse generators is possible due to increased requirement of electric power
consumption generally only with line power devices. Thus however pulses can be transferred
over larger distances up to approximately 200 m surely. You find a representation of the
position as well as the connection types in the figures 6 and 7 as well as the specification of
the pulse values in table 2. The technical data please take from the paragraph: „Technical data
of the NAMUR-Pulse sensors“. All pulse generators are certified for hazard areas and possess
a EEx conformance certificate.
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1.7.4. HF-NAMUR-Pulse sensor
HF NAMUR pulse generators are optionally possible in the counter heading (HF1 and HF2)
and at the turbine wheel (HF3). The quantometer can be equipped with these sensors
according to demand of the customer. The output signals are in fixed relation to the rotation
of the turbine wheel and can not be changed by the adjustment gear wheels. They serve
generally the control of line powered volume correctors, flow computers or data storage
devices. The pulses can be transferred over larger distances up to approximately 200 m surely.
The specifications in the table 2 are approximate values, whereby the exact impulse values of
an each sensor and meter are determined during the calibration and can deviate from the
indicated value in table 2. The technical data please take from the paragraph: „Technical data
of the NAMUR-Pulse sensors“. All pulse generators are certified for hazard areas and possess
an EEx conformance certificate.
1.7.4.1.HF1 and HF2
This both pulse sensors are positioned in the counter head. There existing reference wheel
generates the pulses in up to two approximation initiators (see fig.4). You find a
representation of the position as well as the connection possibilities in the figures 6 and 7.
Figure 4:
Representation of the HF-pulse sensors HF1 and HF2 in the counter head
1.7.4.2. HF3
The pulse sensors HF3 is positioned in the meter body (see fig.3). The pulses of the turbine
wheel are generated by the sensors HF3.
The sensor is an approximation initiator and possess a separate plug (see fig.5).
Figure 5:
Pattern of the connector of the HF pulse sensor HF3 in the meter body
1.7.5. Link specification of the electrical pulse sensors
Whether a pulse sensor is available and which impulse value of these possesses, you can take
from the pulse generator sign of the industrial quantometer (fig.13).
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Figure 6:
Position of the NF and HF pulse sensors in the counter head of the quantometer CPT
NF1
Socket 1
Socket 2
Pin
1
4
2
5
3
6
1
4
2
5
3
6
Polarity
−
+
−
+
−
+
−
+
−
+
−
+
x
x
Figure 7:
1
x
2
x
Socket 3
NF3
3
4
x
x
x
x
HF1
5
NF2
6
7
8
x
Socket 4
NF4
9
10
11
x
x
x
HF2
x
12
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
- Standard connection of the complete version
- Alternative connections
Diagram of connections of the pulse sensors in the counter head of the quantometer CPT
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1.7.5.1. Pulse sensors in the counter head
The position and the connectors of the possible pulse generators in the counter head are
represented in the figures 6 and 7. The standard version contains only the NF Reed contact
NF1. All other sensors can be installed on customer's request. The connection of the electrical
pulses to the installation for clients is made by the sockets So1 and So2, whereby So2 is
installed optionally with more than 3 sensors or on customer's request in the counter head.
The electrical connection to the socket is to be implemented over a plug of the company
Tuchel with the designation C091 31 H006 100 6. An information plate (see fig.14) of the
electrical specification of the socket is positioned on the rear side of the counter head.
1.7.5.2. Pulse sensors in the meter body
The position of the optionally pulse generator in the meter body is represented in the figure 3.
The detection of the electrical impulses is made by the respective plug at the sensor. The
electrical connection could be realised to the 4-pin plug by a coupling socket of the company
Tuchel with the designation C091 31 D004 100 2. An equipment of the meter with this sensor
has to be required in the meter order. A retrofitting can be done by the manufacturer only, or
executed by assigned technical personnel.
Figure 8:
Assembly hole for the HF-pulse sensor HF3 in the meter body
1.7.5.3. Technical data of the Reed-Contacts
The Reed-Contacts are passive sensors and used for low-frequency output signals only. They
have the following technical data:
max switching voltage
24 V
max switching current
100 mA
contact resistance
0,15 Ω
max switching frequency
500 Hz
1.7.5.4.Technical data of the NAMUR-Pulse sensors
The NAMUR-Pulse generators are active sensors and used for low or high frequency output
signals. They have the following technical data:
supply voltage
8,2 V
supply current inactive (low)
< 1,2 mA
supply current active (high)
> 2,1 mA
load resistance
1 kΩ
max switching frequency
5 kHz
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The circuitry of the electrical connection is represented in figure 9 and the output signals
which can be expected in figure 10.
Figure 9:
Diagram of connections of the inductive NAMUR initiators
inactive state: UL < 1,2 V, active state: UH > 2,1 V
Figure 10:
Output signals of the inductive NAMUR initiators
1.7.6. Pressure measurement
The measurement of the operating pressure of the quantometer can be done by the reference
measuring tap pr. This is available at the front side of the meter (see fig.3). In that way it will
take place at the front without attention of the installation position. The thread dimensions for
the connection of a screw connector is represented in the figure 11.
Figure 11:
Dimensions of the reference measuring tap
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1.8. Designation and signs
The technical basic parameters of the industrial quantometer are noted on the type plate
(fig.12). It is equipped on the front of the counter head.
The specification concerning pulse outputs and their value can be taken from the pulse
generator sign on the top side of the counter head (fig.13).
The flow direction is indicated by arrows (fig.15) on the front and rear side of the meter body.
The marking of the pressure measuring point takes place at the meter body according to the
representation in figure 16. In similar manner also the pulse generator HF3 is marked.
Figure 12:
type plate
Figure 13:
Pulse sensor sign
Figure 14:
Sign for the connector identification of the pulse generators in the counter head
Figure 15:
Arrow on the meter body for the
specification of the flow direction
Figure 16:
Information designation for
the pressure measurement
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2. Measuring values
The gas volume, which flows through a quantometer, is displayed by the counter concerning
the operating or line conditions pressure, temperature and compressibility only. In order to
determine a comparable value independently to the respective operating conditions for
accounting purposes, a conversion of the volume to standard conditions Vn is used. The
standard volume determines itself from the following calculation:
Vb pb Tn
Vb 273 * (pü + 1)
Vn = — * — * — ≈ — * —————
k pn Tb
Z
(t + 273)
Definition:
Vb – operating volume [m³/h]
Tb
Vn – standard volume [m³/h]
Tn
pb – operating pressure at the meter [bar] k
pü – operating over pressure at the meter [bar]
pn – standard pressure [bar] (1,01325 bar) Z
t – operating gas temperature [°C]
Zn
(1)
where k = Z/Zn
– standard gas temperature abs. [K] (273,15 K)
– operating gas temperature abs. [K]
– compressibility factor k (constant or
calculation by GERG 88)
– real gas factor
– real gas factor (standard condition: Zn ≅ 1)
The operation volume Vb of a measuring period determines itself from the difference of the
counter statuses of the quantometer the at the beginning and to the end of the period. The
operation over pressure pü is determined on the reference pressure point pr of the meter as
average value. The operation gas temperature t can be measured by a temperature sensor in
the down stream pipe of the meter in accordance with PTB test rules Volume 20. The
compressibility factor is determined by using the gas quality, at systems up to 10 bar as
constant or at higher pressures than variable over calculation methods in accordance with G
486.
3. Measuring accuracy
Each real measurement is falsified by measurement inaccuracies. These errors can be divided
at the quantometer in two substantial categories:
1. Error by the physical characteristics of the measurement principle.
2. Error by the installation-conditioned influence of the gas flow.
3.1. Error of the measurement principle
The measuring characteristic of quantometers is represented in figure 17. Dependence to the
EWG guideline of volume gas meters the margins of error are determined on the following
values:
Qt – Qmax
Qmin – Qt
≤ ± 1,5 %
≤±3%
where at quantometers Qt = 0,2 Qmax
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Figure 18:
Error characteristic of a quantometer
 Low pressure error curve;
- - - - - - High pressure error curve
The measurement range of the COMMON quantometers is indicated in table 2. As more
highly the operating pressure rises, becomes the error curve more flatter (see fig.17) and the
minimum flow Qmin becomes more smaller within the admissible limits of error. Thus a larger
measuring range can be obtained with higher operating pressures, which could be up to a
relation of 1:50.
The on density depending minimum flow value Qmin,ρ can be calculated according to the
following relation:
Qmin,ρ = Qmin
* iρ = Qmin *
ρw
— = Qmin *
ρ
ρw * 1,013
Qmin
————— ≈ 1,1 * ——————
ρg * (p + pa)
ρg * (p + pa)
(2)
Definition:
Qmin,ρ – minimum flow value under operating pressure [m³/h]
Qmin – minimum flow value according to table 2 [m³/h]
iρ
– coefficient
ρw – density of the gas of the verification [kg/m³]
ρ
– density of the operation gas with operating pressure [kg/m³]
– density of the operation gas with atmospheric pressure according to table 1 [kg/m³]
ρg
p
– gas overpressure in front of the quantometer [bar]
pa
– atmospheric pressure [bar]
The figure 18 shows a diagram to the determination of Qmin,ρ with determined operating
pressure. Based on the operating pressure and the temperature it has to be determined the
density. In dependency of this density values, the coefficient iρ can be determined from the
right page of the diagram. Under help of the formula in the diagram (fig.18) it is possible to
calculate the appropriate Qmin,ρ under operating pressure by using the Qmin value from table 2.
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Figure 18:
Diagram for the determination of the Qmin - value at defined operating pressure and operating
temperature
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3.2. Error of the installation
Quantometers are inferential gas meters and therefore dependent on the direction, distribution
and the homogeneity of the gas flow.
The integrated flow conditioner allows with an upstream pipe length of 5xD a measurement,
mainly free of perturbations. An elimination of perturbations can be obtained with a
COMMON flow conditioner PS, installed in the upstream pipe.
In the case of pulsating or intermittent gas flows, which cause a run after of the turbine wheel
of over 1% in relation to the operation flow, a quantometer without special add-on modules is
not suitable. In these cases volume measuring instruments should be used, as for example the
COMMON rotary gas meters CGR.
4. Pressure loss
The gas meter causes an inevitable pressure loss. This is limited by the maximum value
according to DIN 33800. The pressure loss values of the individual nominal sizes at a gas
density ρ0 = 1kg/m³, that can be taken from the diagram of the figure 19.
The real pressure loss ∆pre is calculated according to the following formula:
ρ
∆pre = —
ρ0
*
pa + p
——— ∆p
pa
(3)
Definition:
ρ – gas density according to table 1
∆pre – operating pressure loss
ρ0 – reference gas density (ρ0 = 1kg/m³)
p – gas over pressure in front of the meter
∆p – pressure loss for gas density ρ0 (Abb.19) pa – atmospheric pressure (pa = 1bar)
Figure 19:
Pressure loss diagram of the quantometer CPT of a density ρ0 = 1 kg/m³
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5. Transport and storage
The quantometer CPT is a precise measuring instrument and is to handle with the utmost
caution.
The following points are to be considered:
During transportation the meter is not to be thrown or to expose strong vibrations.
The meter is to be transported and to be stocked in the appropriate installation position.
The gas meter should be transported in the original packaging up to the place of work.
Removing from fabrication catches and transportation covers is only recommendable at the
installation place.
A raising of the quantometer at the counter head is not admissible.
It is to be paid attention to as dry a storage as possible. The meter is to be protected against
precipitation and other humidity.
It is to be made certain that by the transportation and by remove of the packing no seal is
damaged or is removed.
For mentioned above transport damages the manufacturer does not take over a warranty.
6. Installation
Before the gas meter is installed, it should be checked again, if the meter meets the
requirements of the gas measuring system. Very important is the check of the pressure rate
PN of the installation, the maximum installation pressure pmax and maximum the flow rate
Qmax under operating conditions, as well as the right flow direction.
The preferred position for the installation of the quantometer is an horizontal installation. The
counter head has to be above in each case. A vertical installation has to be adapt by the
production. Specially the flow direction from down upward is to be avoided and possible only
by special manufacturing.
The gas meter has not to be installed at the deepest point of the installation, because otherwise
condensate or contamination can settle in the meter and thus the function and measuring
accuracy can be affected.
The installation of quantometers should take place in closed rooms or cabinets if possible. In
open air installations the meter has to be protected by suitable measures from precipitation,
contamination or direct sun exposure. The area of application is with a gas temperature
between -10°C and +60°C. The lowest ambient temperature has to be not lower than -25°C.
The installation, into which the quantometer has to be installed, should be conceived
according to the technical guideline TR G 13, because otherwise by the manufacturer no
warranty for the adherence of the error limits can be given. To adherence the measuring
accuracy, normally an upstream pipe distance of 5 x DN is sufficient. It is to be made certain
too, that the gas flow does not indicate an intermittent or pulsating character, which can cause
a tracking error of ≥1%.
In order to achieve a very high measuring accuracy of the gas meter, the company offers also
complete meter runs with upstream and downstream pipe and a COMMON flow straighter.
This flow straighter is a Sprenkle Flow conditioner according to DIN EN ISO 5167-1. The
pressure loss thus increased is to be inferred from the paragraph of the same name.
The installation of the gas meter has to take place without tension into the piping. With larger
meters the pipe installation, or if necessary the meter, is to be supported. It is to be made
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certain that the meter is to be built concentrically into the piping and no seals loom into the
piping.
It has to be paid attention of possible contamination of the gas, which can damage the meter
and cause an influence of the measuring accuracy strongly. If possible, a filter has to be
installed in front of gas meter, which has a fineness of minimal 10µm. In the starting phase a
start sieve is recommendable, which avoids a damage of the meters by welding or installation
pollution. This is to be removed however after some time again from the pipe installation, in
the case of contamination which were held back by the start sieve, will generate a flow
disturbance, which can have an influence on the measuring accuracy. The manufacturer of the
quantometers does not take responsibility for damage to the gas meter, which from
insufficient filtering or contamination in the piping results.
The connection of volume correctors and add-on modules has to take place using the
prescribed plug connectors (paragraph "link specification of the electrical pulse generators").
7. Putting into operation
During the admission of the quantometer with operating pressure largest caution is required,
because by the difference of pressure for pressure-free subsequent installation briefly large
gas flows can occur, which can load then the gas meter over the permitted flow and destroy
the measuring cartridge. Filling the pipe installation by the installed quantometer should be
avoided. You find an example of the structure of a measuring system in
figure 20.
– case a bypass in the installation is available, is before opening the valves 1 and 2 pre and
behind the gas meter the following piping through to open the valve 4, to be filled.
Afterwards over a needle valve 5, if it is available, or by very slow opening of input valve
1 the meter can be set under operating pressure. After it the output valve 2 is only to open
slowly. As last step may not be forgotten to close the valves 4 and 5 again.
– with absence of the bypass at first the meter is by slow opening of the output valve 2 to
connect with that follows installation. Afterwards very slowly and carefully the input
valve 1 is to be opened, whereby the danger of the brief overload is very large here.
– for the purpose of the disassembly the meter installation has to be emptied. If a bypass is
available, the valve 4 is to open as the first one. The meter has to be separated from the
gas flow by slowly close from the input valve 1 and the output valve 2. Afterwards the gas
meter is to be emptied over the bleed valve 3 slowly.
Figure 20:
Pattern of a measuring system with bypass
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8. Maintenance and lubrication
Quantometers have to be serviced from instructed technical personnel only. Strong operation
noises or jerky run point on a damage of the gas meter.
The industrial quantometer require no lubrication. The bearings of the main shaft of the
turbine wheel are self lubricated.
9. Seals
The seal positions can be taken from the figure 21.
Figure 21:
Seal positions of the quantometer CPT
If a seal was damaged or removed, the guarantee goes out for the measurement accuracy of
the meter.
Seals for add-on modules are not marked. At special information it is pointed out, that blind
screw connections which are not be used by sensors, can be sealed too.
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